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SAMPLE SENTRY®
SAMPLE CONDITIONING
MODULES
Installation, Operation and
Maintenance Manual
SPD 1.1.9
Rev. 2
02/04
Web: www.sentry-equip.com
e-mail: sales@sentry-equip.com
SPD 1.1.9 Rev. 2
Sample Sentry®
REVISION HISTORY
Rev. ID
Date
Notes
0
10/00
This is the initial release of the Sample Sentry® manual SPD
1.1.9. The previous manual is obsolete. Significant changes
have been made along with reformatting.
1
2
11/01
02/04
Page 27. 4-04771A and B changed to 6-02352F and E
Replaced old Warranty with new Warranty SPD 4006 Rev 0.
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
ii
SPD 1.1.9 Rev. 2
Sample Sentry®
TABLE OF CONTENTS
Technical Specifications
……………………………………………………………
Page
1-2
Quick Start Guide
……………………………………………………………
3
Principle of Operation
Automatic Mode
Manual Mode
Blow down
Alarms
……………………………………………………………
……………………………………………………………
……………………………………………………………
……………………………………………………………
……………………………………………………………
4
7
8
9
9
Setup and Calibration
Sampling System
Controller Setup & Calibration
Automatic Startup Switch
Flow Meter Setup
Pressure Reduction Valve Setup
Electrical
……………………………………………………………
……………………………………………………………
……………………………………………………………
……………………………………………………………
……………………………………………………………
……………………………………………………………
……………………………………………………………
10
10
11
14
15
16
17
Operation
Indicators
Controls
Valve Control
Automatic Operation
Manual Operation
……………………………………………………………
……………………………………………………………
……………………………………………………………
……………………………………………………………
……………………………………………………………
……………………………………………………………
18
18
19
20
20
21
Maintenance
Trouble Shooting Guide
Maintenance Report
……………………………………………………………
……………………………………………………………
……………………………………………………………
22
22
24
List of Components
……………………………………………………………
25
Warranty
……………………………………………………………
27
Appendix
Good Sampling Practices
Communications
Component Descriptions
High Pressure Solenoid Valve
Maintenance
……………………………………………………………
……………………………………………………………
……………………………………………………………
29
29
31
32
……………………………………………………………
37
Drawings
……………………………………………………………
40
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
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iii
SPD 1.1.9 Rev. 2
Sample Sentry®
TECHNICAL SPECIFICATIONS
Sample Sentry® Controller
Power Requirements….....……………
Sample Conditions
Max Flow Rate………………
Sample Inlet Temp.....…...…..
Ambient Conditions…..……...
Analyzer Sample Pressure…...
Flow Accuracy………………
Displays
Upper………………………...
Lower………………………...
Indicators.............….........…………….
Keypad.....................…......……………
Control Set points & Alarms
Controlled sample flow rate.…
Startup Pressure…………….
Blow down Duration..........…..
Temperature Alarm...........…...
Pressure Alarm Setpoint...…...
Valve Control…………………………
Measurements and Displays…………..
Serial Communications………………
115 or 230 VAC, 50/60 Hz, VA=150
0 to 4,000 cc/min
32 to 1000°F (0 to 532°C)
32 to 140°F (0 to 60°C)
Held constant at approximately 20 psig, depending upon grab
sample flow rate
+ 5% of flow reading when BPR/RV is controlling
4 digit, 0.6" High, green, 7-segment LED displays flow rate
(cc/min)
3 digit, 0.6" high, green, LED displays final sample, cooling
water-out and optional temperature (°F or °C) and reduced sample
pressure (psig)
Red LEDs light to indicate alarms, displayed parameters and
solenoid valve position
Six tactile feedback membrane switches for sample valve, blow
down valve, display, auto/manual, alarm reset and reset.
800 to 3,580 cc/min, switch selectable
0-1800 psig (POT adjustable) (0-124 bar)
0, 2, 4, or 6 minutes, switch selectable
120 or 140°F (49 or 60°C), switch selectable
220 psig (15 bar)
Single speed proportional control. 7 psi deadband
Final sample temperature
Cooling water outlet temperature
Sample flow rate
Conditioned (reduced) sample pressure
Optional third temperature
RS485 protocol at 2400 baud, 16 stations per serial port with
SAMPSEN™
Pressure Measurement
Accuracy……………………………..
Overpressure…………………………
Range………………………………...
Process Connection…………………..
Operating Temperature………………
+1% of full scale
Proof: 250% of FS
Inlet: 0 to 3000 psig
¼” NPT
-40 to 250°F
Burst: 750% of FS
Sample: 0 to 300 psig
Motor Data
Power…………………………………
Torque………………………………...
110Vac
9 in-lbs at 50 rpm
Temperature Measurement
Type…………………………………..
100Ω RTD
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
1
SPD 1.1.9 Rev. 2
Sample Sentry®
Accuracy……………………………...
Range…………………………………
+1°F
0 to 300°F
Design Goals
Obtain representative sample
• Pressure and temperature alarms on high conditions
• Adjustable alarm levels
Automatic sample flow control
• Motorized VREL® or needle valve
• Adjustable flow set-point
• Maintains constant flow in sample lines
Automatic sample startup
• Automatic startup as inlet pressure rises
• Auto shut off when sample flow is below set-point
• Pressure and temperature alarms stop sample flow
Automatic sample blow down
• At each restart
• Adjustable pressure setting
• Adjustable blow down duration
Network communications are provided for remote display, control and data acquisition
Modes and Switches
Controller Modes
Manual
Start
Run
Stop
Membrane Switch Buttons
Alarm/Reset
Display
Sample
Blow Down
Auto/Manual
Reset/Start
Throughout the text of the manual an italicized word will represent one of the modes of the
Sample Sentry®. A word in bold implies the use of a button on the membrane switch.
NOTE: Sentry reserves the right to change any specifications without notice.
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
2
SPD 1.1.9 Rev. 2
Sample Sentry®
QUICK START GUIDE
The following are a set of steps used to start up a Sample Sentry® panel. The guide should be used in
conjunction with the remainder of the manual to build a full understanding of Sample Sentry®.
•
Sample tubing - all field installed sample tubing must be blown out and hydrostatically tested before
initializing sample to the panel. A guide for choosing sample tube sizes is included in appendix A.
Sentry will assist in sizing and suggestions for sample tubing.
•
Cooling -Always ensure cooling water has been introduced to the panel. Make sure all the sample
cooler valves are open.
•
Initial power up - introduce power to the panel before any sample flow is initiated. All Sample Sentry®
displays will light up. Flow rate will be zero and the current temperature will show in the lower display.
•
Starting Sample Sentry®- when power is introduced to Sample Sentry® it will begin in automatic mode
and perform these steps. Do not introduce sample pressure to the panel. Leave the sample isolation
valve closed.
o
o
o
o
o
Sample Sentry® checks for complete closure of the pressure reduction valve (PRV). If the
valve is not closed the controller will close it automatically.
Once the PRV is closed the controller will open the sample valve. The PRV will open
attempting to introduce flow. The isolation valve is still closed; no sample flow should be
introduced to the panel.
Sample Sentry® will continue to open, until the valve reaches fully open. The sample valve
will close and the PRV will begin to close. The stop LED will light.
When the PRV fully closes the controller will wait in start mode. The start LED will be lit.
Each step will occur in this sequence any time a Sample Sentry® is powered down or reset.
Shutting off the isolation valve and running the controller through these steps is a good way
to periodically test correct operation. Please see the troubleshooting guide at the end of the
manual if the sequence of operations didn’t complete.
•
Sample Sentry® will wait in start mode until it sees sample pressure. Open the isolation valve to
introduce sample. Sample Sentry® begins the blow down sequence by opening the blow down valve
and starting to open the PRV. Preprogrammed blow down time counts down toward zero. The
PRV will either open all the way or stop when the sample temperature reaches 110°F.
•
When the blow down time reaches zero. The blow down valve and the PRV will close.
•
Sample Sentry® senses the PRV is closed and opens the sample valve. The controller turns the PRV
open until it reaches the preset flow set point.
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
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3
SPD 1.1.9 Rev. 2
Sample Sentry®
PRINCIPLE OF OPERATION
Sample Sentry® is designed to automate the sampling process. Today’s power plants ramp pressure and
come on and offline often. Changing plant conditions alter sample temperature, flow rate, and pressure.
Sample Sentry® measures sample conditions and delivers a constant flow rate, temperature, and reduced
pressure. Sample Sentry® is comprised of sensors, solenoid valves, and a controller. Sample temperature,
cooling water outlet temperature, sample flow rate and conditioned sample pressure are continuously
monitored. The controller uses sensor data to adjust flow rate and control solenoid valve position.
Normal operating characteristics are displayed. Abnormal conditions trigger visual alarms.
PRV
Figure 1: Typical piping and instrumentation diagram (P&ID) of a Sample Sentry®.
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
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4
SPD 1.1.9 Rev. 2
Sample Sentry®
Figure 1 is a typical P&ID of a Sample Sentry® system. Figure 2 shows a Sample Sentry® mounted on a
sampling rack. Common parts of the Sample Sentry® referred to in the text are labeled in figure 2.
Sample Sentry® measures two sample pressures, at the inlet (PT1) and after pressure reduction (PT2). In
automatic mode, Sample Sentry® controls the startup of the sample line based upon the inlet pressure.
Automatic startup will occur as long as Sample Sentry® is in start mode. When the controller is in start
(start LED is lit on the face of the controller) the Sample Sentry® has correctly shutdown and inlet
pressure is below the startup set point. If the controller is in stop the Sample Sentry® has shutdown but
there is still some pressure at the inlet. Sample Sentry® will not switch into start until the inlet pressure
drops below the startup set point. Upon sensing pressure the controller starts the blow down sequence.
Blow down’s purpose and operation is described in detail below. The startup pressure is programmable;
see setup and calibration for more details.
Figure 2: Picture of a full Sample Sentry® assembly in a sampling rack.
After pressure reduction valve (PRV), pressure transducer (PT2) indirectly measures flow rate. Sample
flow is calculated from differential pressure maintained over an orifice. PT2 is directly upstream of the
orifice; downstream of the orifice is a Sentry backpressure regulator (BPRV). The BPRV provides a
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
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5
SPD 1.1.9 Rev. 2
Sample Sentry®
constant backpressure and the other half of the differential pressure measurement. Any foreign objects
between the orifice and BPRV will skew flow rate readings. Orifice size determines the flow range
Sample Sentry® can control to. Sentry specifies two orifice sizes, one for low flow applications, and one
for high flow applications. A 0.041” orifice measures flow rates between 800 and 1760 cc/min. For flow
rates between 1560 and 3580 cc/min a 0.063” orifice is used. The low flow orifice is installed in the
factory and the high flow orifice is shipped along with the final product. Look in the setup and calibration
section for instructions on choosing orifice size and setting the flow control set point. If the reduced
pressure ever exceeds 225 psig Sample Sentry® will go into alarm. In alarm the sample or blow down
valve and PRV will close. All features of Sample Sentry® will be locked out until the alarm is cleared.
Pressure must drop below 225 psig to clear the alarm.
Sample flow rate is controlled to maintain constant sample flow regardless of fluctuations in inlet
pressure. Necessary sample flow is determined by summing together the flow needed in each analyzer.
Flow in excess of that required by the analyzers is routed to the sink for use as a grab sample. EPRI has
studied optimal flow velocities in a sample line. Typically 1200 cc/min of water in a ¼” sample lines
satisfies EPRI recommendations. A 3/8” line requires 3300 cc/min. Sizing a sample line for a steam
samples requires a more detailed analysis based on temperature, pressure, and length of line. Appendix A
is dedicated to determining line sizes. Please contact Sentry if there is any question on sample line size.
Temperature readings are taken downstream of the secondary cooler (TE1) and after pressure reduction
(TE2). Temperature element TE1 measures the sample sent to the analyzers. With quality secondary
cooling reduced sample temperature is consistent over time and from sample line to sample line.
Consistent sample temperature makes trending repeatable over time. Temperature element TE2 is used to
ensure the primary cooler is not overloaded. Sample temperature after the primary cooler should never
exceed 60°C. Temperature above 60°C causes boiling in the cooler shell. Boiling the cooling water will
create scaling and premature tube breakage. Optional temperature sensor (TE3) at the cooling water
outlet monitors shell water temperature. TE3 is optional and can be placed at any point less than 150°C.
The temperature alarm is active for all three sensors and programmable to 50 or 66°C. If any one sensor
exceeds the alarm set point temperature the controller shuts down the sample valve (SV-2) and closes the
PRV. The LED next to the temperature sensor in alarm flashes until the temperature is reduced below the
set point. During an alarm no features of Sample Sentry® are enabled. Valves cannot be opened. To
regain control reset the alarm by pressing alarm/reset. After a reset the controller is in manual mode. To
return the controller to automatic control press the auto/manual button.
A motor driver driven by the controller turns the PRV as the inlet conditions change. The controller
keeps the flow rate constant. The PRV is either a needle valve or a VREL®. A needle valve is used on
lines with inlet pressures less than 500 psig, a VREL® on lines between 500 and 3500 psig. The
controller calculates the flow rate from the reduced pressure measurement. Flow rate is kept constant by
adjusting the position of the PRV as inlet conditions change. Constant flow assures a representative
sample in applications where source pressure varies.
Sample Sentry® controls sample valve SV-2, and blow down valve SV-1. The blow down valve opens
automatically as pressure is introduced to the system. Blow down time is programmable at 0, 2, 4, and 6
minutes. Blow down is designed to clean the sample line; other types of blow down should be used to
clean the water at plant startup. If the quality of the sample water at startup is a problem, place the
Sample Sentry® in manual and open the blow down valve. In manual blow down continues indefinitely,
samples are taken from the blow down outlet. After blow down the sample valve opens to initiate sample
to the analyzers. Placing the controller in manual allows the user to actuate the valves from the display
panel. Caution should always be taken in manual. Opening the sample valve with the PRV open will
damage pressure transducers, flow meters, and analyzers. Both sample and blow down valves close if an
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
6
SPD 1.1.9 Rev. 2
Sample Sentry®
alarm condition is sensed by any of the temperature or pressure transducers. The valves cannot be opened
until the alarm is cleared.
Following is a synopsis of the abilities and features of Sample Sentry®
• Adjustable temperature alarms for sample temperature, cooling water outlet, and optional
temperature sensor.
• Pressure alarm on high-reduced sample pressure.
• Blow down at each restart with an adjustable pressure setting.
• Adjustable blow down duration.
• Network communications for remote display and control.
• Automatic sample flow control maintains main sample line velocity and flow.
• Automatic startup based on rising inlet pressure.
• Automatic sample shutdown when unable to maintain constant flow set point.
• Automatic sample shutdown when an alarm condition is sensed.
Automatic Mode
This is Sample Sentry’s® "normal" mode and the system can remain in this mode indefinitely. Sample
Sentry® enters automatic mode on power up, after reset, completion of startup, or from a communications
command. In automatic mode, Sample Sentry® controls total sample flow. Sample Sentry® holds total
flow rate constant while inlet conditions change. The sample and blow down valves are automatically
controlled. Blow down time is programmable to 0, 2, 4, or 6 minutes. Alarms automatically shut all
valves to protect instruments in the sample line.
Typical operation of Sample Sentry® in automatic mode begins with the unit in start. Start implies no
inlet pressure. During a plant startup sample pressure begins to build. When the inlet pressure reaches
the startup set point the controller initiates blow down. Blow down begins by opening the blow down
valve and starting to open the PRV. The PRV continues to open until it reaches full open. If the
temperature at TE2 exceeds 45°C the PRV will stop protecting the cooler from overload. An overloaded
primary cooler will push the sample temperature into alarm and shutdown the controller. After the PRV
is open the blow down time continues to countdown until the end of the programmed time. The PRV and
blow down valve close at the end of the programmed time. When the PRV reaches its closed position
Sample Sentry® switches into run. In run the sample valve opens and PRV starts to turn. Opening the
sample valve initiates flow; the PRV continues to open until the sample flow rate set point is maintained.
Sample Sentry® cycles the PRV to maintain the set point indefinitely. The flow rate at which Sample
Sentry® controls is set by dipswitch. Detailed setting information is included in the setup and calibration
section.
Sample Sentry® shutdowns if the flow control set point cannot be met. Generally a shutdown occurs as a
plant shuts down and sample pressure is lost. The PRV turns full open in an attempt to maintain flow. If
the PRV opens fully and flow cannot be maintained the sample valve closes and the unit goes into stop.
In stop the PRV closes. When the PRV reaches the closed limit, Sample Sentry® does one of two things.
One, the controller moves into start. The advance to start always occurs when the inlet pressure is
relieved. Two, the controller stays in stop. If for some reason the inlet pressure is still high but flow has
been lost (plugged sample line) the controller stays in stop until the inlet pressure is relieved. Once the
pressure is relieved the controller advances to start and is ready to begin the cycle again. Occasionally a
plugged sample line or a leak initiates shutdown.
Automatic control is interrupted by alarms. Alarms occur due to high pressure or high temperature. An
alarm condition signals the controller to shut the sample valve, close the PRV, and move into stop. The
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
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7
SPD 1.1.9 Rev. 2
Sample Sentry®
measurement in alarm flashes its LED. In alarm Sample Sentry® controller is locked. No user input is
accepted. Pressing the alarm/reset button on the front keypad resets the alarm. Alarms cannot be reset
until the pressure or temperature is reduced below the set point.
Below is an overview of the actions that occur in automatic control. The cycle begins and ends in start.
The controller indicates which mode it is in with LED’s next to the lower display. See Figure 4 for a
picture of the face of the controller.
Start
•
•
•
•
•
•
•
•
The PRV, sample valve, and blow down valve are closed.
Activated by inlet pressure (PT-1) rising above auto startup set point.
Blow down starts and the time is displayed in lieu of the flow rate.
If blow down time is zero, controller advances to run.
Blow down valve opens.
PRV opens.
Time counts down from set point to zero, in ten-second increments.
Blow down valve closes.
Run
•
•
•
•
•
Stop
•
•
•
•
PRV closes.
Sample valve opens.
PRV opens until flow equals set point.
PRV cycles to maintain constant flow.
Flow and sample temperature are displayed.
Flow is below set point with PRV fully open.
Sample valve closes.
PRV closes.
When the pressure falls below startup set point, controller advances to start.
Manual Mode
Manual mode is entered a couple of different ways. Pressing the auto/manual button on the front keypad
changes the controller to manual mode. If the controller is in run the sample valve and PRV close. The
operator will not have control until the PRV has fully closed. Sample Sentry® runs in manual only with
the auto startup pressure switch SWB1, Switch 3, OFF. In manual only mode, Sample Sentry® displays
temperature, pressure and flow. Alarms are still active. In manual the sample and blow down solenoid
valves are controlled from the membrane switch (see figure 4). The operator adjusts sample flow rate
using the motor driver switch.
Blow down
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
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8
SPD 1.1.9 Rev. 2
Sample Sentry®
Blow down begins the control sequence in automatic mode. The controller waits in start until the inlet
pressure exceeds the startup pressure set point. The controller opens the blow down valve and PRV. The
PRV either opens fully or stops when the reduced sample temperature reaches 110°F. Blow down is set
for 0, 2, 4, or 6 minutes; it is designed for cleaning the sample line only. At the end of the programmed
time the blow down valve and PRV will close. The controller advances to run.
Blow down can also be initiated by opening the blow down valve in manual mode. If the sample needs to
be cleaned for an extended length of time, Sentry recommends opening the blow down valve in manual
mode. Samples can be taken from the blow down line until the sample is clean. Once the sample is clean
the controller can be placed in automatic mode by pressing the auto/manual button.
Alarms
Alarms occur due to high temperature, and pressure. A time-out alarm happens from PRV drive failure.
An alarm overrides both manual and run modes. The purpose of alarms is to protect sample equipment
from high temperature and high pressure. A distinct set of actions occur during any alarm condition as
listed here:
•
•
•
•
•
The PRV closes.
Sample and blow down valves close.
The display of the sensor(s) in alarm flashes. Numerous alarms may be flashing.
Pressing alarm/reset will reset alarms that no longer exceed the set points.
On pressing alarm/reset the system will return to automatic control.
The controller’s functions are locked out from the user while an alarm condition exists. To recover
control the alarm condition must be cleared and the alarm/reset button pressed. After the alarm is
cleared the controller is in manual. To return to run press the reset button.
The set point of the temperature alarm is adjustable to either 50 or 60°C. Alarms for TE1 and TE3 are
always enabled; TE2’s alarm can be disabled. See the setup and calibration section for instructions on
setting and disabling the temperature alarm. PT2 actuates the pressure alarm. The pressure alarm set
point is 220 psig. PT1 does not have an alarm. The flow control driver includes a timed out alarm.
Timed out occurs if there is a failure in the PRV driver. The flow control driver times out if the fully
open limit switch is not made in a reasonable amount of time. Please see the troubleshooting guide for
information on clearing the timed out alarm.
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
9
SPD 1.1.9 Rev. 2
Sample Sentry®
SETUP AND CALIBRATION
Before operating a sampling system a set of startup conditions must be met. Before operating Sample
Sentry® the user needs to set up operating conditions of the controller. This section begins with steps to
ensure the sampling system is ready for use. The final portion of the section details preparing the Sample
Sentry® controller for use.
Sampling System
To startup a Sentry sampling system a few critical details must be attended to. This is a brief discussion
of the system please refer to the users manual for a detailed description of the sampling panel.
The first step towards commissioning the sample panel is to connect the sample tubing. Before
terminating the tubing at the panel each tube must be blown out or flushed with water. Stray metal
shavings or weld slag will lodge inside the panel plugging lines. Sentry recommends all sample tubing be
hydrostatically tested before sample is introduced. Please direct any questions about tubing size or
routing to Sentry. Sentry has the ability and expertise to help in any application.
The most critical part of the sampling system is cooling water. Cooling water is the first component
turned on and the last turned off. Operating a system without or with insufficient cooling water is a safety
risk and damages the coolers. Never allow the cooling water outlet temperature to exceed 140°F.
Temperatures above 140oF imply localized boiling within the cooler shell. Boiling weakens sample tubes
and eventually creates tube failure. To minimize localized boiling throttle cooling water on the
downstream side of the cooler. Throttling on the downstream side of the cooler ensures maximum
pressure inside the shell, minimizing the chance of localized boiling.
The last step is to close all the isolation valves and pressure reduction valves (PRV). Introduce sample in
steps. First release the root valves. This brings sample to the isolation valves. Check for leaks. Open the
isolation valve with the PRV closed and check for leaks. With Sample Sentry® on the sample line place
the controller in automatic. In automatic Sample Sentry® closes the PRV and automatically control the
sampling line.
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
10
SPD 1.1.9 Rev. 2
Sample Sentry®
Controller Set Up and Calibration
Sample Sentry® allows certain operational set points to be controlled via a dual set of dipswitches. The
dipswitches are located on the face of the display board (see Figure 3). The display board is accessible by
removing the front cover. Sample Sentry® allows the user to set the flow control range and set point. Two
temperature alarm set points are available as well as the ability to disable the alarm for TE2. Units of
measure, English or SI, can be set for temperature and pressure. The automatic startup switch can be
disabled. With automatic startup enabled a blow down duration can be chosen. A distinct
communications address is available for up to sixteen Sample Sentry’s®.
Figure 3: Picture of the display board inside the Sample Sentry®.
Use figure 3 to identify the positions of the dipswitches as well as control potentiometers. The following
tables detail the proper switch settings:
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11
SPD 1.1.9 Rev. 2
Sample Sentry®
Switch Bank 0 (S0)
S0-1 thru S0-4: Switches 1 to 4 set the flow control set point. A 0.041” orifice measures flow between
800 and 1760 cc/min. A 0.063” orifice is for high flow from 1560 to 3580 cc/min.
Switch 1
Switch 2
Switch 3
Switch 4
ON
ON
ON
ON
ON
ON
ON
ON
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
ON
OFF
OFF
OFF
OFF
ON
ON
ON
ON
OFF
OFF
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
Low Flow
cc/min
800
820
860
900
970
1030
1120
1180
1270
1350
1420
1490
1560
1620
1680
1760
High Flow
cc/min
1560
1560
1620
1700
1820
1980
2120
2200
2400
2560
2720
2880
3020
3160
3420
3580
Table 1:
S0-5: Enables or disables alarm conditions for temperature element 2. Referring to figure 1, TE-2 is the
temperature after primary cooling and pressure reduction. Enabling the alarm allows the sample flow to
shut down if the primary coolers are not performing. Sentry sizes coolers such that the sample
temperature and corresponding cooling water temperature is less than 140°F. Temperatures above the
alarm set point indicate the possibility of localized boiling which damages the cooler.
S0-5
OFF
ON
TE-2 Alarm Status
Alarm off
Alarm on
S0-6: Sets the threshold of the temperature alarms, TE-1, TE-2 (if enabled), and TE-3. The alarm is
factory set at 140°F, the maximum temperature recommended at the outlet of a cooler. A lower set point
is available for better protection.
S0-6
OFF
ON
Temperature alarm set point
120°F (49°C)
140°F (60°C)
S0-7: Sets the unit of measure for temperature and pressure.
S0-7
OFF
ON
Units
English: temperature in oF and pressure in psig
SI: temperature in oC and pressure in barg
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12
SPD 1.1.9 Rev. 2
Sample Sentry®
S0-8: Configures Sample Sentry® for use without a backpressure regulator. The backpressure is part of
the differential pressure for flow measurement. Sample Sentry® may be used without a backpressure
regulator as long as flow vents to atmosphere with minimal pressure drop.
S0-8
OFF
ON
Backpressure Valve
None
Present
Switch Bank 1 (S1)
S1-1 and 2: Blowdown duration
S1-1
ON
ON
OFF
OFF
S1-2
ON
OFF
ON
OFF
Blowdown Time (min)
0
2
4
6
S1-3: Disables automatic startup of the Sample Sentry®. Without automatic startup Sample Sentry®
controls flow but must be started up manually. Required for automatic control of a sample line.
S1-3
OFF
ON
Setting
No pressure switch option
Pressure switch active.
S1-4: Orifice size is chosen based on the required flow rate. Two orifices are available, 0.041” and
0.063”; the associated flow ranges are detailed above.
S1-4
OFF
ON
Setting
Low range orifice
High range orifice
S1-5 thru S1-8: Set the station number of each controller for use over a multidrop serial network. Up to
16 Sample Sentry’s® can be networked. Each controller must have a unique station number.
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13
SPD 1.1.9 Rev. 2
Sample Sentry®
Station No
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Switch 5
ON
ON
ON
ON
ON
ON
ON
ON
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
Switch 6
ON
ON
ON
ON
OFF
OFF
OFF
OFF
ON
ON
ON
ON
OFF
OFF
OFF
OFF
Switch 7
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
Switch 8
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
Table 2:
Automatic Startup Switch
To automatically control a sample line the startup switch compares the signal from the inlet pressure
transducer with the startup switch set point. When the inlet pressure increases above the set point,
Sample Sentry® begins to blow down the sample line. The set point is controlled with potentiometer R19. Figure 3 shows the location of the startup pressure adjustment potentiometer. Table 3 is the
relationship between the scale around the potentiometer and the inlet pressure. Three methods of setting
the startup pressure set point are listed below:
1.
To obtain an approximate startup set point, adjust R-19 using table 3 to set at the desired pressure.
2.
A more accurate method is to connect a digital voltmeter between test point TP-6 (+) and GND test
point (-). Set the startup pressure adjustment pot (R-19) to the proper voltage shown in table 3.
3.
The final option is to adjust the pot (R-19) to startup at the current system pressure. Start with the
pot fully clockwise. When the system reaches the desired startup pressure turn R-19 counterclockwise until the Sample Sentry® begins to blow down.
Approximate startup
Scale on startup pressure
Voltage between
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14
SPD 1.1.9 Rev. 2
Sample Sentry®
pressure (psig)
0
300
625
925
1250
1550
1850
2150
2450
2775
3075
3300
adjustment POT
1
2
2½
3
3½
4
4½
5
5½
6
6½
7
TP-6 and GND
0
0.4
0.75
1.0
1.34
1.65
1.95
2.25
2.55
2.85
3.16
3.46
Table 3:
Flow Meter Setup
The flow meter included with Sample Sentry® is made of three parts, orifice, pressure transducer, and
constant backpressure. The controller reads the signal from the pressure transducer and converts it into a
flow rate. Orifice size is dependent upon the required total flow rate. A 0.041” orifice produces flow
rates between 800 and 1760 cc/min. For higher flow rates, 1560 to 3580 cc/min, a 0.063” orifice is used.
The orifice is mounted in an assembly directly downstream of the pressure transducer. Install the orifice
with the part number facing downstream. Any foreign material between the pressure transducer and
orifice creates inaccurate flow readings. A clogged orifice results in high flow rates with low actual flow.
Cleaning the orifice will rectify the situation. Sample Sentry’s® flow meter is calibrated at the factory. If
necessary, re-calibration can be done in the field. The procedure following calibrates the controller and
pressure transducers for accurate flow rate. (see Figure 3 for potentiometer locations on board).
The reference voltage must be set to 2.55 VDC. Remove the controller cover and connect a digital
voltmeter between test points TP-3 (+) and GND (-) on the display board. Set the meter range for 0-5
VDC. Adjust VREF pot (R-8) to 2.55 VDC + 0.005 VDC. R-8 has been set and sealed at the factory and
should not be changed unless necessary.
The offset and gain of pressure transducer PT-2 are calibrated for accurate pressure readings. VREF must
be set before adjusting flow pots. Follow the steps below to calibrate the pressure transducer. The
pressure transducer is factory set and sealed, change only if necessary.
•
•
•
•
•
•
Remove the 0-300 psig pressure transducer (PT-2) from the system (it is the lower transducer
upstream of the orifice fitting). Connect it to a pressure source adjustable from zero to 225 psig.
Turn the system on and press the manual button on the controller. Push the display button to
display pressure.
Apply 20 psig to the transducer and adjust the flow offset pot (R-27) until the displayed pressure
indicates 20 psig.
Apply 200 psig to the transducer and adjust the flow gain pot (R-31) to obtain a displayed pressure
of 200 psig.
Repeat steps 3 and 4 several times until 20 and 200 psig are adjusted correctly. (Each setting affects
the other and requires this iterative procedure.)
Re-install the transducer in the system.
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15
SPD 1.1.9 Rev. 2
Sample Sentry®
Pressure Reduction Valve Setup
Sample pressure determines the type of pressure reduction valve (PRV) used in a sample line. A metering
valve is used on sample lines with inlet pressures less than 500 psig. A VREL is used for sample
pressures from 500 to 3000 psig. Both valves have Cv’s that vary linearly with the number of turns. The
controller indicates a motor drive problem by actuating the time-out alarm or by not advancing modes.
Sentry sets and tunes each motor drive in the factory. Periodically the drive may need to be adjusted.
There are two components in the motor drive setup, the number of turns of the motor, and the coupling
between the motor and PRV. Occasionally the coupling between the motor and the PRV loosens. To
drive a VREL, the motor driver board is adjusted to allow 50 turns of the motor. A VREL has 55 turns,
leaving 2.5 turns at the fully open and fully closed position. For a metering valve, the motor driver board
is adjusted to 10 turns of the motor. The metering valve has 12 turns, leaving one turn at each end of the
valve. The Sample Sentry® controller must remain in strict relationship to the actual position of VREL.
If the motor shaft is allowed to turn without also turning the VREL shaft, this relationship will be lost and
the system will not function properly. The following procedure ensures the controller agrees with the
actual position of the VREL. At the end of this procedure, both the controller and the VREL will be in
the fully closed position.
1.
2.
3.
4.
5.
Uncouple the motor and PRV.
Grasp PRV shaft and turn clockwise (closed) by hand until PRV shaft stops.
Turn PRV shaft back counterclockwise two full turns, for VREL, one turn for a needle valve.
Run motor closed, using rocker switch, until the motor stops.
Replace the connection between motor and PRV.
To accommodate different type of PRV’s the number of turns the motor makes is adjustable. On the motor
board is a set of optical switches. One switch indicates open the other closed. A metal flag is attached to the
motor and runs between the two switches. The closed switch is mounted on an adjustable slide. Moving
that slide changes the total turns of the motor. Refer to figure 4 and the procedure below to set the number
of turns.
•
•
•
•
•
•
•
•
•
•
Remove the cover over the motor driver board.
Ensure the shunts on the motor driver board (J4 and J6) are over the 1 and 2 positions. Positions
1 and 2 are toward the bottom of the board.
Uncouple the motor from the valve.
Turn the VREL two turns or needle valve one turn from fully open.
Using the motor switch, run the flag to the top (Open) limit. Let the limit stop the motor. Too
much background light will affect the limit operation. Shield from outside light or work in a dim
area.
Recouple the valve and motor.
Close the PRV until the motor stalls.
Open the VREL two turns or needle valve one turn.
Slide the lower limit on the motor driver board up to the flag. Leave the flag flush with the
bottom of the limit.
Check to see that the lower limit flag slot lines up with the circuit board slot and tighten the
screws until snug.
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16
SPD 1.1.9 Rev. 2
Sample Sentry®
Figure 4: Picture of the motor board with limit switch.
Electrical
Sample Sentry® is designed for operation on single phase 110 or 220 VAC at 50 or 60 HZ. The voltage
input for a Sample Sentry® without a motor driver and/or solenoid valves can be field selected. The
switch is located on the power supply board mounted underneath the display board (see drawing number
12-03252D). Voltage supply on units supplied with motor drivers and/or solenoid valves is factory set.
The components determine the voltage setting; do not change the voltage switch.
Route incoming power through a fused disconnect or circuit breaker. Size the fuse or breaker to handle
150 VA for each Sample Sentry®. Sentry recommends placing a surge suppressor/filter, such as an
Isobar® manufactured by Tripp Lite, between the fuse or breaker and the Sample Sentry®. Low pressure
solenoid valves have a coil inrush current of 3 A (Models 101L, 201L, 101M, 201M). High pressure
solenoid valve have a coil inrush current of 23 A lasting for 1/10 second.
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17
SPD 1.1.9 Rev. 2
Sample Sentry®
OPERATION
This section of the manual explains how to operate a Sample Sentry®. The section begins with the
operation of the front panel.
Figure 5: Picture of the front face of the Sample Sentry®. Shows both displays, status LED’s, and switches.
Indicators
Sample Sentry® continuously displays total flow in cc/min on the upper display panel. The lower display
panel allows the user to select between temperature or pressure display. The LED’s on the left side of the
lower display indicate the origin of the value currently shown. The membrane switch will have either
English or SI units printed on it. Dipswitch 7 of switch bank 0 sets units in the microprocessor. During
blow down, the upper display panel shows the amount of time remaining. After blow down the flow rate
is displayed.
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18
SPD 1.1.9 Rev. 2
Sample Sentry®
The controller cycles through different modes as it runs, an LED on the right side of the display indicates
the mode. Modes are labeled as manual, start, run, and stop. Flashing LED’s adjacent to each
measurement indicate an alarm condition. Wired in parallel with the sample and blow down valves are a
set of indicating lights. When a valve is open the light is on.
Controls
Six switches along the bottom of the Sample Sentry® control panel operate the controller. The action of
each switch is detailed below. Remember, during an alarm condition the user is locked out from all
switches but alarm/reset.
Alarm Reset
Depress the switch for one second to clear and reset an alarm. The alarm will not reset if the
measurement still exceeds the alarm level. During an alarm the controller advances to manual. Upon
reset the controller stays in manual until the user presses reset/start and returns to automatic control.
Display
Depressing the display switch steps the lower display panel through temperature and pressure values.
The LED on the left side will light next to the currently displayed value. The measurements are sample
temperature 1 (final sample temperature), sample temperature 2 (optional temperature sensor), cooling
water out temperature, and conditioned sample pressure. The controller defaults to sample 1 temperature
on start up or reset.
Sample
Works only in manual. This switch allows manual toggling of the sample valve. When the sample valve
is open, a red light near the valve indicates the valve is open. The sample valve closes whenever the
controller is switched to auto. The sample valve is normally closed on loss of power.
Blow down
Works only in manual. This switch allows manual toggling of the blow down valve. When the blow
down valve is open, a red light near the valve indicates the valve is open. The blow down valve closes
whenever the controller is switched to auto. The blow down valve is normally closed on loss of power.
Auto/Manual
The auto/manual switch alternates the controller between run and manual. The controller defaults to run
or start upon power up. Below is a description of what will occur when the user presses auto/manual.
Automatic to manual mode
• With controller in run the sample valve and PRV close. No control over sample, blow down, or
PRV until the PRV has completely closed.
• With controller in start or stop, manual control is available immediately after pressing the switch.
The PRV and control valves are already closed.
• While in blow down pressing the auto/manual switch closes the blow down valve and the PRV.
No control over sample, blow down, or PRV until the PRV has completely closed.
Manual to automatic mode
• The final mode depends upon the presence of inlet pressure. The first action upon pressing
auto/manual is the sample, blow down, and PRV closes.
• With inlet pressure above the startup set point the controller is in run controlling at the flow set
point.
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19
SPD 1.1.9 Rev. 2
Sample Sentry®
•
With inlet pressure below the startup set point the controller advances to start and waits for the inlet
pressure to build.
Reset Start
Resets the CPU. Use alarm/reset if the unit stops or operates erratically. The controller defaults to run.
Valve Control
A Sample Sentry® is supplied with either manual or automatic pressure reducing valve (PRV) control.
Automatic valve control maintains flow rate regardless of pressure fluctuations. The PRV is connected to
a motor with a belt. Sample Sentry® monitors the current flow rate and cycles the valve to maintain the
set point. The user is able to move the PRV manually with a switch. In manual mode the switch directly
controls the motor drive, the PRV can be completely opened and closed. In automatic mode the valve can
be temporarily moved, once the switch is let go the valve will adjust to maintain the control point.
The user is responsible for setting the flow rate with a manually controlled PRV. The Sample Sentry®
monitors and displays flow rate but will not keep the flow rate constant. The PRV must be closed before
opening the sample or blow down valves. If the PRV is not closed the pressure wave created from
opening a solenoid valve will damage components such as the pressure transducer.
Automatic Operation
At power up or after reset/start Sample Sentry® enters run or start depending on inlet pressure.
Advancing to start implies there is low inlet pressure. During plant startup sample pressure begins to
build. When the pressure reaches the startup set point Sample Sentry® initiates blow down. Blow down
begins by opening the blow down valve and starting to open the PRV. The PRV continues to open until
fully open or the temperature at TE2 exceeds 45°C. At 45°C the PRV stops opening to prevent
overloading the primary cooler. If the primary cooler is overloaded Sample Sentry® will go into alarm
and shutdown. After the PRV is open blow down continues to countdown until it reaches the end of the
programmed time. At the end of the programmed time the blow down valve closes and the PRV begins to
close. When the PRV reaches the closed position Sample Sentry® switches to run. The sample valve
opens and the PRV starts to open. Run initiates sample flow, the PRV continues to open until the sample
flow rate set point is met. Sample Sentry® cycles the PRV to maintain the set point indefinitely. The
flow rate at which Sample Sentry® controls is set by dipswitch. Dipswitch settings are included in the
setup and calibration section.
Sample Sentry® shuts down if the PRV is fully open and the flow control set point cannot be met.
Generally this occurs as the plant shuts down and sample pressure decays. Occasionally a plugged
sample line or a leak initiates shutdown. If the PRV does fully open and flow cannot be maintained the
sample valve closes and the controller goes to stop. The PRV begins to close. When the PRV reaches the
closed limit Sample Sentry® makes one of two choices. One, the unit advances to start. Start mode
always occurs with low inlet pressure. Two, the unit stays in stop. If the inlet pressure is high but flow
has been lost (usually due to a plugged sample line) Sample Sentry® stays in stop until the inlet pressure
is relieved. Once pressure is relieved the controller advances to start and is ready to begin the cycle
again.
Automatic mode is interrupted by alarms. Alarms occur due to high pressure or high temperature. Alarm
conditions always cause the controller to shut the sample valve, close the PRV, and move to stop. To
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20
SPD 1.1.9 Rev. 2
Sample Sentry®
determine the measurement in alarm a LED flashes. Pressing the alarm/reset button on the front keypad
resets the alarm. Alarms cannot be reset until the pressure or temperature is reduced below the set point.
Until the alarm is reset the Sample Sentry® will be locked. No user input is accepted during an alarm
condition.
A set of LED’s to the right of the bottom display panel shows the current operating condition. A
description of the actions that occur during each condition are listed here:
Start
•
•
•
•
•
Run
•
•
•
•
Stop
•
•
•
PRV, sample, and blow down valve are closed.
Activated by inlet pressure (PT-1) rising above startup set point.
Blow down begins; the time is displayed in lieu of flow rate.
Blow down valve opens; PRV begins to open.
After time is elapsed controller moves to run.
Always begins by closing PRV, sample, and blow down valve.
Sample valve opens.
PRV cycles to maintain constant flow.
Flow and Sample 1 temperature (TE-1) are displayed.
PRV has opened all the way without the ability to maintain the required flow rate.
PRV, sample, and blow down valves close.
Will wait until inlet pressure decays below startup set point.
Manual Operation
Manual mode is entered a couple of different ways. Pressing the manual button on the front keypad
during automatic operation changes the controller to manual mode. If the controller was in run the
sample valve and PRV will close before control is given to the user. If auto start up pressure switch
SWB1, Switch 3, is off, the controller goes to manual at reset or power up. In manual mode, Sample
Sentry’s® primary function is to provide temperature, pressure, and flow monitoring display and alarms.
If provided, the sample shut off and blow down solenoid valves are controlled by the controller
membrane switch. The operator adjusts sample flow rate manually using either the VREL® (high and
medium pressure) or needle valve (low pressure). Temperature and pressure alarms are active in manual
and shut all valves on actuation.
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21
SPD 1.1.9 Rev. 2
Sample Sentry®
MAINTENANCE
Troubleshooting Guide
Q1: Why is the time-out light on and I’m completely locked out from the control panel?
A1: The time-out alarm occurs when the motor does not reach the open limit switch. Something in the
operation of the motor driver has occurred such that the flag coupled to the motor driver is not tripping
the limit switch. To immediately regain control, uncouple the motor and PRV and press start/reset.
Place the controller in manual and follow the suggestions below. There are three components that cause
this problem.
The most common problem is the PRV is mistuned. The valve reaches full open and stops before the flag
on the motor has tripped the open limit switch. A complete tuning procedure is included in setup and
calibration. It is also possible the motor has too many revolutions. After uncoupling the motor and valve
use the manual open/close switch to run the motor. Count the number of complete revolutions of the
motor shaft from fully open to closed. A VREL motor shaft will turn 50 times, a needle valve will turn
10 times. If the revolutions need to be adjusted follow the procedure in setup and calibration.
The motor included with Sample Sentry® is not a continuous duty motor. It is designed to run for a few
minutes at a time and will overheat if run continuously for 15 minutes or more. An internal overload will
trip on overheating and shut down the motor. Allow the motor to cool down and press the start/reset
button to regain control of the Sample Sentry®.
If none of the above fix the problem, the trouble probably resides on the motor board itself. Check the
limit switch on top of the board (see figure 4) and ensure it is screwed down tightly. If nothing works
replace the motor board. The motor board part number is 6-02229A.
Q2: The Sample Sentry® begins to close but the motor locks up, the belt is taught, and the
controller stays in stop.
A2: This condition is caused by a misalignment between the valve and motor driver. Please see the
tuning procedure in setup and calibration.
Q3: The PRV has closed correctly but the controller stays in stop and won’t advance to start.
A3: The controller will only advance to start when the inlet pressure has reduced below the startup
pressure set point. Open the front face of the controller and turn R19 (startup set point adjustment) slowly
counter-clockwise (see figure 3). Once the set point goes below the inlet pressure the controller will
advance to start. If the controller will not go to start even with R19 fully counter-clockwise the pressure
transducer may be damaged. Unplug PT-1 from the bottom of the controller; this will advance the
controller to start. Plug the transducer into the PT-2 slot, if the transducer is damaged the pressure on the
controller will read 255 psig and the pressure alarm will come on.
Q4: The flow display is higher than the actual flow?
A4: Depending on the severity of the reading difference there is different solutions:
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22
SPD 1.1.9 Rev. 2
Sample Sentry®
If the difference is within 5% of actual the flow gain pot needs to be adjusted. Place the controller in
manual and find a steady flow rate. Adjust the flow gain (see figure 3) until the actual flow and the
measured flow are equal.
If the difference is greater than 5% it is generally an orifice problem. First, check the orifice for
contamination. The orifice is inside the assembly directly downstream of the pressure transducer, PT-2.
Any foreign material in the orifice housing will decrease the Cv and throw off the flow calibration.
Second, check the size of the orifice. The size is printed on the orifice. Ensure that dipswitch 4 of switch
bank 1 is set to match the orifice size installed.
Q5: The controller is in pressure alarm even without flow or inlet pressure.
A5: The flow transducer has been damaged from a pressure spike. The pressure transducer, PT-2, Sentry
part number 4-04771A, needs to be replaced. Opening the sample valve when the PRV is not closed
causes pressure spikes. Always close the PRV before opening the sample valve. In the short term the
transducer can be unplugged from the controller. Sample Sentry® can be operated in manual, there will
not be a flow reading.
Q6: In automatic mode the Sample Sentry® starts, blows down, attempts to sample but closes down
because it cannot maintain flow.
A6: Generally this occurs due to an occlusion in the sample line. The sample line is partially blocked,
but pressure builds up without any flow. The pressure build up is enough to trigger the startup pressure
switch but during sampling the block in the sample line does not allow enough flow. Often this can occur
on low pressure steam lines. With low pressure steam the sizing of the sample line is very important.
Please see appendix A or call Sentry for technical support.
Q7: None of the buttons on the controller will work, all the valves are closed and I cannot get any
sample.
A7: The Sample Sentry® is in alarm. Identify the source of the alarm. Either one of the four indicator
lights to the left of the lower display will be blinking or the time-out light above the display will be on. If
the time-out light is on see question/answer 1. For an alarm on one of the measured properties the
controller will not allow any interface until the measurement drops below the alarm value. See the
specification section for a list of the alarm values. Once below the alarm value use alarm/reset to reset
the alarm and auto/manual to return the Sample Sentry® to automatic mode.
Q8: I have high pressure solenoid valves and I hear a click when I press the button but the valve
does not open to let flow through.
A8: The high pressure solenoid valves require a 10ms 23A current surge to lift the plunger against
pressure. There is a valve driver board mounted next to the power supply that provides this quick pulse
of current. Both boards are located beneath the display board. There is a set of fuses on the board that
may need to be replaced. The click is caused by the hold coil pulling in but without the initial lift off
pulse the valve will not open.
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23
SPD 1.1.9 Rev. 2
Sample Sentry®
Maintenance Report
Affected
Parts
Date
Software
2-03775M
9/96
Display
Board
6-02175A
Motor
Driver
Board
6-02229A
Solenoid
Valve
4-04770A
3/97
3/98
4/98
VREL
7-00744E
10/97
Motor
Drive
Bearing
2-04433A
Plastic
Guard
2-03919F
Valve
Position
Flag
5/97
Pressure
Transducer
4-04771A
&B
Software
2-03775M
10/97
Problem and Solution
Problem: Sample Sentry® shuts down during blow down. The flow rate
available while the VREL is fully open overloads the cooler and trips the
temperature alarm
Solution: A new software revision. The new software stops the VREL from
opening more once a temperature set point is reached. The reduced flow rate
keeps the cooler from overloading. Software rev VREL896
Problem: The Sample Sentry® will not progress to start after shutting down.
Solution: A new revision of the board with a redesigned pressure switch analog
input. Changed rev from 2 to 3. R33 will not be installed in the new board.
Problem: The motor driving the valve acts erratically. The action is jumpy.
Solution: A new revision of motor driver board. The drive resistor for the
optical isolator is sized correctly. Newest revision is 4.
Problem: On a low pressure sample line, the solenoid valve drops most of the
pressure upstream of the flow control valve. The large pressure drop reduces the
dynamic range of the flow control valve making it impossible for the Sample
Sentry® to control the flow rate.
Solution: Replace the solenoid valve on any low pressure line (<150 psig) with
4-05117H. The solenoid valve has a larger orifice and a pressure rating of 150
psig.
Problem: The valve binds and stalls out the motor
Solution: The new VREL includes a bearing on the internal side of the threaded
shaft, greatly reducing the amount of torque required to turn the valve.
Problem: The brass spacer is unable to hold the belt tight enough to prevent
skipping. The spacer also wears quickly making the problem worse.
Solution: Moved the bearing from the front of the motor mount out onto a
bracket. The bracket slides along slotted holes so the belt tension can be adjusted.
Problem: The old guard does not fit over the new drive assembly
Solution: The guard was changed slightly to make it fit correctly.
9/93
Problem: Originally the flag was made of plastic. The flag broke easily.
Without a flag the motor driver does not know when to stop trying to close the
valve.
Solution: Install a new metal flag and retune the system.
Problem: Connector on top of the original transducer would leak water ruining
the transducer.
Solution: A new transducer with a watertight automotive type connector.
10/99
Problem: User is able to open the sample valve in manual mode while the
pressure reducing valve is open. Often this action will destroy the pressure
transducer.
Solution: A new software revision will not allow the user to open the sample
valve until the pressure reducing valve is in the closed position.
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
24
SPD 1.1.9 Rev. 2
Sample Sentry®
LIST OF COMPONENTS
Sentry Part
Number
Description
Drawing
Controller
6-02902A
6-02902B
6-02175A
6-02176A
6-02177A
6-02178A
4-01607B
4-04468B
4-04468C
2-03775M
2-03739A
2-03739B
Low pressure or air operated solenoid valve controller
High pressure solenoid valve controller. Includes auxiliary driver
board for Atkomatic valves
Display Board
Power Supply Board
Auxiliary Power Supply Board
Analog Connector Board
Power Supply Board Fuses F1 and F2, Fast Blow, 3A
Auxiliary Power Supply Fuses F1 and F2 Littelfuse 3136.25, 3AG,
Slo Blo, 6 1/4A
Power Supply Board fuse F3, Littelfuse 230.25, 2AG, 1/4A
Programmed microprocessor
Membrane switch, English units
Membrane switch, SI units
12-03252D
12-03252E
12-03252F
12-03252D,E
12-03252D,E
12-03252D,E
Motor Driver Board
Valve position flag for low pressure needle valve
Valve position flag for high pressure VREL
Motor Rocker Switch
Motor
Motor Run Capacitor
Motor Bearing (external)
VREL® Pulley
Motor Pulley
Needle Valve Pulley
Bore/Reducer for Needle Valve Pulley
Belt
Needle Valve Bearing Spring
Motor Bracket Spring
Motor Bracket Mounting Assembly, Rivnut
VREL®Safety Shroud
Needle Valve Safety Shroud
Motor Driver Board Shield
Motor Shaft Support Bracket
12-03252C
12-03252C
12-03252A
12-03252B
12-03252C
12-03252B
12-03252C
12-03252A
12-03252A,B
12-03252B
12-03252B
12-03252A,B
12-03252B
12-03252C
12-03252C
12-03252A
12-03252B
12-03252C
12-03252A
12-03252D,E
12-03252D,E
12-03252E
12-03252D,E
12-03252F
12-03252H
Motor Driver
6-02229A
6-02351D
6-02351C
4-04766A
2-03919L
4-04764A
4-02157B
4-03397E
4-03397D
4-03397F
4-04890A
4-03399E
4-04997A
4-01163D
4-01763S
2-03919F
2-03919G
2-04108A
2-04433A
Solenoid Valves
4-04770D
4-04770E
4-04770A
4-04770B
High Pressure
115Vac/60Hz
High Pressure
220Vac/50Hz
Medium Pressure
115Vac/60Hz
Medium Pressure
Atkomatic
sample
and
blow
down
valves,
12-03252A
Atkomatic
sample
and
blow
down
valves,
12-03252A
sample and blow down valves, 200 to 2000 psig,
12-03252A
sample and blow down valves, 200 to 2000 psig,
12-03252A
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
25
SPD 1.1.9 Rev. 2
Sample Sentry®
4-05117H
4-04020E
220/50 - 240/60
Low Pressure sample and blow down valves, <200psig
Sample & Blowdown Valve Indicator Lights
12-03252A
12-03252B
Pressure Reducing Valves
7-00744A
6-02302C
2-03748E
7-00744E
6-02302F
4-04745C
6-02303A
4-04791C
4-04791D
6-02457E
6-02457F
4-04745D
Manual VREL®
VREL® Seal Kit - Non-motorized Includes seal, back-up and thrust
washer with installation instructions.
Bronze Bushing
Motorized VREL
VREL® Seal Kit - Motorized
Ball Bearing for use in Motorized VREL
Taper Rod & Nut
Manual Needle Valve - Low Cv
Manual Needle Valve - High Cv
Motorized Needle Valve - Low Cv
Motorized Needle Valve - High Cv
Needle Valve Bearing, (2 required)
12-03252A
12-03252A
12-03252A
12-03252B
12-03252B
12-03252B
Transducers
4-04774E
4-04774F
4-04774A
6-02352F
6-02352E
6-02345A
6-02345B
Low Range Orifice, 0.041"
High Range Orifice, 0.063"
Orifice housing, .041 orifice
0-300 psig
0-3000 psig
Temperature Sensor Assembly, 8ft long, includes phone plug
Temperature Sensor Assembly, 3ft long, includes phone plug
12-03252K
12-03252K
12-03252K
12-03252K
12-03252K
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
26
SPD 1.1.9 Rev. 2
Sample Sentry®
WARRANTY
Seller warrants products manufactured by it and supplied hereunder to be free from defects in
materials and workmanship for a period of twelve months from date of shipment. If within such
period any such products shall be proved to Seller’s satisfaction to be defective, such products
shall be repaired or replaced at Seller’s option. Seller’s obligation and Buyer’s exclusive remedy
hereunder shall be limited to such repair and replacement and shall be conditioned upon
Seller’s receiving written notice of any alleged defect within 10 days after its discovery and, at
Seller’s option, return of such product to Seller, ex-works Sentry’s factory.
The foregoing warranties are exclusive and in lieu of all other express and implied warranties
except in title, including but not limited to implied warranties of merchantability and fitness for
purpose. Seller shall not be subject to any other obligations or liabilities whatsoever with respect to
products manufactured or furnished by it, or any undertakings, acts or omissions relating thereto.
Warranty Conditions & Limitations
This Warranty shall not apply to any Sentry product which, in the opinion of Sentry Equipment
Corp, has been (a) altered or repaired in a manner affecting the efficiency of performance of the
unit or (b) incorrectly installed or operated or (c) damaged in shipment or (d) damaged by flood
or fire or (e) if the serial number is missing, altered or defaced.
The owner shall be responsible for maintenance of his equipment. Wear or damage caused by
lack of normal maintenance or by misuse of the equipment shall not be considered as defective
workmanship and material.
Sentry reserves the right to make product design changes or improvements without notice and
without imposing any obligation upon itself to install these changes or improvements on its
products previously manufactured.
This warranty is for the sole benefit of the original purchaser and is not transferable unless
agreed to in writing by Sentry Equipment Corp.
Receiving Shipments (including loss or damage by transportation)
It is the customer’s responsibility to check for missing cartons and sign of damage to cartons. If
found, customer should note missing and/or damaged cartons on the delivery receipt and have
delivery receipt signed by the representative of the transportation company. If unpacking
discloses concealed damage from rough handling, the customer should request a concealed
damage inspection from the transportation company.
The Sentry Customer Service Department will aid your organization in any claim proceeding for
shortages or damages in shipment, but it is the receiver’s responsibility to file claim with the carrier
for damage or loss.
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
27
SPD 1.1.9 Rev. 2
Sample Sentry®
Customer Actions For Claims on Products During the Warranty Period
1. Contact the Customer Service Department, Sentry Equipment Corp., Oconomowoc,
WI, Telephone: 262-567-7256, to obtain a Return Material Authorization (RMA)
number.
2. You will be sent an “RMA” and a “Decontamination Statement” that is required to be
filled out and returned with the equipment.
3. The following information must appear on the outside of the package:
a.
RMA number marked on outside of box.
b.
Decontamination Statement filled out and attached to outside of box.
4. Return defective equipment FREIGHT PREPAID. Collect shipments will be refused.
5. The factory will not process warranty claims until the customer has properly
accomplished the above items.
6. The Sentry factory may accept the entire claim, a part of the claim or none of the
claim if our inspection of returned parts proves the failure was for reasons other than
defective material or factory workmanship.
Important Notes:
1. Sentry will not be responsible for damage incurred during the return shipment.
2. All returns subject to inspection and a $50.00 evaluation fee.
3. This RMA is not authorization for credit. Credits and/or replacements will be issued
upon evaluation of returned goods.
4. RMA is valid for thirty (30) days from issue date.
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
28
SPD 1.1.9 Rev. 2
Sample Sentry®
APPENDIX A
Good Sampling Practices
In addition to proper flow and temperature control in the Sample Sentry® conditioning module, upstream
piping/tubing which transfers the sample to the module is critical in helping assure a representative sample.
Water samples usually do not change state during sample transport and therefore a relatively constant sample
velocity should be maintained throughout the entire sample line. If the sample velocity is too slow upstream
of the Sample Sentry® module, constituent deposition increases, affecting sample representivity (see Figure
A-1). Also, the lag time between a current condition change at the sample source and recognition by
analysis is very long, since the new sample takes a considerable time to reach the conditioning and analysis
equipment. For example, a water sample flowing in a 200' long 0.25" O.D x .049" wall tube at 1200 cc/min
(6 fps) will take approximately 33 seconds to reach the Sample Sentry® module. The sample (1200 cc/min
controlled at Sample Sentry®) in a 200' long .375" O.D. x .049" wall tube will take approximately 110
seconds to reach the Sample Sentry® module. If a 1200 cc/min water sample is adequate to meet your entire
analysis requirements, then .25" OD x .049" wall tubing or stronger walled tubing with equivalent inside
diameter should be used for the sample line.
Selecting steam sample line sizes is a much more difficult proposition than water samples because of the
condensation that is occurring in the sample line as the steam passes through it. Two phase flow models
have been developed by Sentry and others to determine the relationship of steam and water velocities,
pressure drop and condensation in the steam sample line. Pressure drop per foot of line can be dramatic and
on lower pressure lines can use up available pressure before the sample reaches the Sample Sentry®
conditioning module.
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
29
SPD 1.1.9 Rev. 2
Sample Sentry®
A balance between the pressure loss, heat loss and velocities in the sample line must be found that gives a
reasonably representative sample. Sample line length and internal and external dimensions must be selected
to determine the best fit. Sometimes insulting the sample line can also improve representivity by reducing
heat loss and keeping the sample in a vapor state until it reaches the cooler. Sample Sentry® has the ability to
solve these problems in the best way possible because of its capability to be placed near the sample source
and monitored remotely. This assures that a steam sample can be taken and quickly converted to water at an
appropriate velocity for representative sampling.
If remote sampling near the steam source isn't feasible, then the following guidelines should be followed
when selecting steam sample lines.
1.
Keep the sample line as short as possible.
2.
Select an I.D. for the sample line that keeps the incoming steam velocity about 30 fps. Avoid
velocity above 40 fps on low pressure steam samples to avoid excessive pressure load in the tubing
prior to the Sample Sentry® module.
3.
Be sure the sample cooler selected is capable of condensing the steam flow. Most steam samples
below 1000 psi probably need a Sentry FLF or FXF cooler to fully condense the steam.
4.
If sample flows are too low or if sample lines are long, consider insulating the sample line to reduce
heat loss and premature condensation.
5.
Consider the following sample line sizes for the listed steam pressures.
Tubing Size
(OD x wall thickness)
.375" x .083"
.375" x .065"
.375" x 0.49"
.5" x 0.83"
Consult Sentry
Pressure Range (psi)
Above 1700
1100 - 1700
800 - 1100
500 - 800
Below 500
Calculations used in determining sample line pressure drop are estimates only, based on theoretical computer
analysis. They should be used with caution.
The sample isolation valve is only for shutting off the sample line. It must never be used to throttle sample
flow. When the pressure is reduced across a partly closed valve and the sample is at or near saturation
temperature, the sample will flash into a steam/water mixture. This will damage the valve seat and it may
not completely shut off sample flow when repairs require line isolation. It can also cause water hammer in
the sample cooler.
The cooling water must be throttled on the downstream side of the cooler, not the inlet side. This approach
gives the maximum cooling water pressure inside the cooler shell, helping eliminate localized boiling at low
cooling water pressure. Boiling should be eliminated since it not only encourages scaling, but also caused
tube vibration and eventual fatigue failures.
Larger diameter tubing can be used for strength but should have equivalent inside diameter to the
recommendations listed above.
Cooling water throttling valve is supplied on the outlet side of the cooler to allow full cooling water pressure
inside the sample cooler shell. This assures that maximum available water pressure will be seen inside the
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
30
SPD 1.1.9 Rev. 2
Sample Sentry®
shell to minimize localized boiling near the hot sample inlet. Always throttle sample cooler on the outlet
side with valved supplied.
Sentry has a variety of computer models to assist you in selecting sample line sizes. Contact the factory at
262/567-7256 for assistance.
APPENDIX B
Communications
Remote communications via an RS-485 network capable of high quality communications at distances up to
5000 feet exists on the controller. Sentry offers a communications software program, called SAMPSEN™,
to monitor, control, record and graphically display data.
An RJ11 (6-6) type modular connector is used for the communications interface and should be connected via
a twisted pair cable as shown in Appendix B. Up to 16 Sample Sentry® modules can communicate on one
network.
The RS-485 protocol network communications port on top of the controller can transmit and receive
information using a computer equipped with an RS-485 serial communications port. The PC-422/485 (part
number GP-IC030-C) board from Black Box 412/746-5565 has operated successfully with Sample Sentry®.
The IC-11 miniature interface RS-232/RS-485 converter from Omega also works with SAMPSEN™ and
Sample Sentry®. A central computer can work with 16 sample stations per port. The station number is
maintained with SWB1 switches 5-8. The baud rate is 2400. Continuous framing analysis. No interrupts.
One stop bit, no parity, 8 data bits. Connections can be made with simple twisted pair cable with stations up
to 5000' from the computer.
Protocol Commands
Station number identification command, 0-15. Begin Automatic Run Mode. Begin Blowdown Start Mode.
Begin Manual Mode. Send Status:
•
•
•
•
•
Position of all switches
Alarm status
Mode status
Temperature, pressure, and flow values
Position of sample and blowdown valves.
The central computer makes all requests, the stations only answer. Call Sentry for more information about
the protocol.
An IBM PC compatible program, SAMPSEN™, is available from Sentry to show status of 16 stations per
screen displaying all status information and allowing transmission of commands. It also graphs and stores
pertinent data. More sophisticated control and communications software is available at additional cost, or
special programming can be furnished.
APPENDIX C
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
31
SPD 1.1.9 Rev. 2
Sample Sentry®
Component Descriptions
Sample Isolation Valve - Low Pressure (V-1)
For samples where the pressure/temperature is less than 500 psig/450°F a globe type valve with 1/4"
compression fittings is supplied. The incoming sample line connects directly to this valve or through a
customer supplied reducer adapter.
Sample Isolation Valve - High Pressure (V-2)
For pressure/temperature up to 5000 psig/1000°F, a globe type valve with 1/4" socket weld connections is
supplied. Incoming sample line connects to the 1/4" socket weld fitting or to a customer supplied
reducer/adapter. A 3/8" socket weld connection is supplied if an FLF cooler is provided.
Sample Cooler (SC-1)
Basic models use the Sentry model TLF-4225 high efficiency sample cooler with removable shell. This
cooler incorporates 2.4 square feet of heat transfer surface. Larger coolers and/or special materials are
available, consult the factory.
Cooling Water Inlet Isolation/Drain Valve (V-3)
The 3-way isolation/drain valve protects the cooler shell side by eliminating the possibility of isolating the
cooler while the sample may still be flowing. If there was no drain vent, the water trapped in the shell and
heated by the hot sample could develop pressures exceeding the shellside rating. The drain valve discharge
is open to the sink. This eliminates the need for a shellside relief valve.
Cooling Water Throttling Valve (V-4)
The cooling water is throttled on the outlet side of the cooler using a globe type valve. This allows the
maximum available cooling water pressure to be seen inside the cooler to minimize the possibility of
localized cooling water boiling at the high temperature sample inlet/cooling water exit.
Flow Control Valve for Low Pressure (PRV-1)
A regulating type needle valve is used for pressure reduction and flow adjustment. Regulating stem type
needle valve provide adequate service with minimum erosion below 500 psig sample pressure. A low or
high Cv (flow coefficient) valve is available.
Flow Control Valve for High Pressure (VREL®)
For pressure above 500 psig a Sentry VREL® is used. The VREL® is a non-wearing rod-in-tube pressure
reducing/flow control device. A unique advantage of this type device is the ease with which crud can be
passed through the system. (See Maintenance Section for details.) This eliminates potential erosion
problems associated with needle valves at higher pressures.
Controller
The Sample Sentry® controller is the operational heart of Sample Sentry®. It includes all signal and power
control and display for the operation of the unit including:
1.
2.
3.
4.
5.
Total sample flow
Primary sample temperature (TE-1).
Secondary sample temperature (optional) (TE-2).
NOTE: If secondary cooling is not used, this temperature probe can be used for cooling water inlet
or other temperature readings - up to 300°F.
Cooling water outlet (TE-3).
Reduced sample pressure (PT-2).
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
32
SPD 1.1.9 Rev. 2
Sample Sentry®
All of the above parameters are displayed on the front face of the Sample Sentry® display panel and include
alarm set points (user programmed) for local indication of out of set point conditions. Operation of the flow
control valve motor driver, auto sample shutoff and auto blow down are also accomplished through the
Sample Sentry® controller when included as options.
Flow Control Valve Motor Driver (M)
An optional feature, the motor driver, in conjunction with the controller, positions the flow control valve to
maintain a constant sample velocity regardless of incoming pressure.
Secondary Cooling (SC-2)
Accurate and repeatable analysis can be dependent upon sample temperature being held consistently at 25°C
(77°F). To achieve this a secondary cooler is installed after the pressure reduction device. Temperature
controlled, chilled water from a refrigeration unit or other chilled water source must be supplied to the
shellside of the cooler to cool the sample to the required level. TE-2 is supplied standard with SC-2, and is
usually located after the flow control valve.
Auto Blowdown (BD) (SV-1)
In applications where Sample Sentry® is in automatic start and stop mode (cycling plants) automatic blow
down can be added to purge the sample line prior to each start up of the system. Blow down time is field
adjustable.
Auto Sample Shutoff (SV-2) (SAMPLE)
The Sample Sentry® controller contains all the appropriate circuitry to provide for automatic sample shutoff
in the event of high sample temperature, pressure or non-constant flow. This provides protection for
sensitive downstream analyzers and helps assure that representative samples are continuously provided. As
an added precaution this option requires manual reset after shutoff for high temperature. In cycling plant
operations the auto sample shutoff valve acts automatically for shutdown and restart based upon incoming
sample pressure. See operating instructions.
Temperature Elements (TE-1, -2, -3)
Accurate integrated circuit temperature elements TE-1 and TE-3 measure the temperature of sample after
pressure reduction, and cooling water outlet, respectively. TE-2 is available as an optional sensor for
customer selected locations less than 300°F. TE-2 is standard with secondary coolers.
Pressure Elements (PT-1, -2)
Pressure elements are state of the art transducers with vacuum brazed wetted section for pressure integrity.
They have excellent repeatability and thermal linearity. Housings are NEMA 3 with RFI protection and are
equipped with a DIN type removable connector. PT-1 has a 0-3000 psig range, PT-2 has a 0-300 psig
pressure range. PT-2 comes will all units. PT-1 is provided when the optional auto sample shutoff or auto
blow down solenoid valves are used.
Backpressure Regulator/relief Valve (BPR/RV)
The combination backpressure regulating and sample relief provides a constant pressure zone between the
flow control valve and the BPR/RV inlet. The relieving feature also assures sample line safety in that it is
designed to relieve the sample line at various pressures depending on flow rate. See figure 3. On-line
analyzers are connected to this constant pressure zone.
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
33
SPD 1.1.9 Rev. 2
Sample Sentry®
Orifice
All models contain an orifice inside a fitting immediately downstream of pressure element PT-2. The orifice
acts as the flow metering device to measure sample flow rate. Two sizes are available: A 0.041" orifice is
used for the low flow range (800-1760 cc/min), a 0.063" orifice is used for the high flow range (1480 - 3580
cc/min). Units are normally shipped with the 0.041" orifice installed. The 0.063" orifice is shipped loose.
Sink Assembly
An optional stainless steel sink assembly with drain is mounted on the panel under the grab sample line.
Dimensions are 10" long x 8" wide x 2 1/2" deep. Drain connection is a 1 1/4" tube/hose.
Filter
A screen filter is shipped loose with the unit. It may be installed in the orifice fitting if sample materials
continuously plug orifice. Use filter screen only when necessary because sample chemistry may be affected.
Cooling Water Sight Gauge
This option provides visual assurance that cooling water is flowing. A spinning impeller is visible through a
sight glass.
Cooling Water Headers - Multi Units
With this option, multiple panels are mounted on a common structure for wall or panel mounting. The
cooling water inlet and outlet manifolds are common, only a supply and drain connection are required. (The
manifold assembly is disassembled for shipping.)
Analyzer Panels
In addition to the Sample Sentry®, Sentry Equipment Corp can provide analyzer panels to monitor a wide
variety of chemical properties. Specific information on the operation and maintenance of these instruments
is provided in the instrument manufacturer's manual.
Sample Connections
Sample line tubing upstream of the Sample Sentry® module should be designed to provide the appropriate
sample flow to attain a representative sample. Variables include source sample pressure, temperature,
pressure drop in sample tubing, and length of sample tubing. See Appendix A for additional information on
sample line sizing or contact Sentry Equipment Corp at 262/567-7256, fax 262/567-4523.
Sample lines should be run with as many straight runs as possible minimizing excessive bends. Allowance
for expansion of the incoming sample line near the sample inlet is necessary.
Standard Unit Sample Line Connection Sizes:
Low temperature and/or pressure:
1/4" compression fitting
Medium and high temperature and/or pressure:
1/4" socketweld fitting
Analyzer line:
1/4" compression fitting
3/8" connections may be supplied on units with higher flow rates and optional F type coolers.
Sink Connections
Sink drain line (if sink is included) can be connected in two different ways:
1.
Clamp 1-1/4" rubber to Tygon tubing to pipe on sink and run tubing to nearest drain.
2.
Solder 3/4" copper tube to the pipe under the sink.
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
34
SPD 1.1.9 Rev. 2
Sample Sentry®
Sample Cooler:
The only service coolers normally require is occasional descaling of the shell side of the coil. This can be
done chemically or mechanically after removing the shell. The frequency of this cleaning depends on the
hardness level and the outlet temperature of the cooling water. When a significant increase in the approach
temperature occurs, it is time to descale the cooler. If the cooler is used in continuous stream service,
inhibited demineralized cooling water may be required to avoid frequent descaling.
VREL®/Needle Valve:
There is no normal maintenance required. In the even of a blockage, it can normally be cleared by retracting
the rods within the valve. Care must be taken to insure that live steam is not discharged during this process.
If after normal maintenance and adjustment the VREL® seals develop a leak and cannot be adjusted, a
VREL® seal kit is available, see VREL® Spare Parts List.
Isolation Valve Packings:
Occasionally during initial start-up or restart of the sample panel, the low pressure/high pressure inlet
isolation valve packing can leak. If this occurs, remove the handle and tighten the packing nut while valve is
in service, then replace handle. If packing continues to leak or other valves/o-rings require maintenance, see
Gaskets and Packing Spare Part List.
Back Pressure/Relief Valve:
The only serviceable part is the diaphragm. No pressure adjustment is available. See Sentry Parts List or
ordering information.
Motor Driver:
Tighten the helical coupling set-screws annually. Inspect coil for damage.
Controller:
Wipe controller dry if moisture drips on enclosure.
Pressure and Temperature Sensors:
Inspect cables and connectors annually.
Orifice:
Disassemble orifice fitting twice per year to inspect for wear and wipe clean. Replace if worn. Avoid
removing pressure transducer (PT-2) during orifice servicing (prevents accidental change in PT-2
calibration). Re-install orifice with part number facing downstream. The orifice fitting must be installed
such that the pressure transducer is upstream of the orifice.
Orifice Screen Filter:
If used, clean orifice screen filter approximately twice per year, depending on sample stream conditions.
SERIAL INTERFACE CONNECTION
RS-485 NETWORK
* RS-485 converters which have been operated successfully with Sample Sentry® and SAMPSEN™ include:
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
35
SPD 1.1.9 Rev. 2
Sample Sentry®
1.
2.
Black box serial interface card GP-ICU30-C (tel. 412/746-5565).
Omega IC-11 RS-232/RS-485 converter (tel. 1-800/226-6342).
APPENDIX D
HIGH PRESSURE SOLENOID VALVE MAINTENANCE
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
36
SPD 1.1.9 Rev. 2
Sample Sentry®
Red Lead
(Start of primary and secondary circuit)
Yellow Lead
(End of primary circuit)
Cylinder
Cap Tube
Black Lead
(End of secondary circuit)
Plunger
Operation of Double Wound Coil
As shown is a schematic view of the double wound coil, looking down. The primary winding is made of a
very heavy wire, and the secondary is made of a very fine wire. When power is applied, it is applied to all
three leads, but because the black and yellow leads are hooked up to the same side of the circuit, you can
only have a complete circuit from black to red and from yellow to red. There is one circuit, yellow to red,
consisting of the heavy wire with a high current affording a high magnetic pull, and the other circuit, black
to red, which has a low current and low magnetic pull.
When the relay cuts out the yellow lead (in less than 1/10 second), it breaks the high current, high pull circuit
(red to yellow) and leave only the low current, low pull circuit (red to black) which has sufficient strength to
hold the valve open.
The important thing is to connect the coil to the Sample Sentry® in such a manner as to insure cutting out the
yellow lead when power is applied. See Figure 5 for wiring instructions. The resistance of a 120VAC/60HZ
coil is 3 ohm across the primary (yellow to red) and 65 ohm across the secondary (black to red).
Maintenance
1.
Coil Replacement: Important Information: When necessary to replace coils on Atkomatic valves,
it is extremely important to replace all parts in the exact position and in the same order as they were
originally installed. Failure to do so will result in faulty valve operation and premature coil burnout.
Parts in different valve series will vary slightly, but all follow the same pattern of installation.
Please check the following drawing for proper parts location. Tubes on end plates must always
extend inside the coil core, and unless there is a yoke around the coil, there must be both a bottom
and a top plate. Coils with yokes do not use end plates. The coil hold down spring must be replaced
on top of the top end plate in series using this spring. Be sure name plate screw or nut is tight.
Please replace name plate. Serial number and operating data are necessary for ordering
parts. All housing parts are a part of the magnetic field. Failure to replace any part correctly will
result in coil failure. Do not turn on current and energize coil until all parts are
replaced and valve is completely reassembled. The new coil should be wired as shown in Figure 5.
One may conveniently splice into the old coil wires if desired.
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
37
SPD 1.1.9 Rev. 2
Sample Sentry®
FIGURE D1: High Pressure Solenoid Coil Disassembly
2.
Cleaning or replacement of parts: WARNING Shutoff power to coil and cut off line pressure.
Bleed pressure to 0 psi before attempting any disassembly.
ANGLE TYPE: Disconnect outlet pipe or tube from bottom nut, unscrew bottom nut from valve
body, and internal parts will drop out.
WARNING: Teflon O rings must always be replaced with new rings when reassembling. It is
recommended that other O rings be examined carefully and replaced if any sign of damage is noted.
Failure to do this can cause external leakage and be extremely dangerous.
Correcting Valve Problems
Normal coil operating temperature when valves are energized for long periods of time is quite high, and coil
assemblies become too hot to touch.
Valves should be handled carefully when installing, and care exercised to prevent damage to the cylinder cap
tube inside the coil housing. Under no circumstances should the valve be tightened on the line by using the
coil housing assembly as a lever or wrench.
When cleaning seat screw or timing orifices, care should be exercised to avoid reaming out to larger than the
original diameter, as this will upset the balance within the valve and prevent proper operation.
ELECTRICAL: Cut off pressure and apply current to coil. On normally closed valves, a metallic click will
be heard if the solenoid is operating. Absence of the click indicates either loss of power supply or a burned
out coil.
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
38
SPD 1.1.9 Rev. 2
Sample Sentry®
MECHANICAL: Excessive wear on internal parts can cause valve to malfunction. To check for wear,
follow instructions under Maintenance paragraph 2 for cleaning or replacement parts to disassemble valve.
Other causes for valve malfunction can include, but are not limited to the following:
1.
2.
3.
4.
5.
6.
7.
8.
WILL NOT OPEN
Cylinder cap tube bent or dented.
Coil housing not properly assembled.
Seat screw orifice clogged.
Foreign matter in valve.
Broken piston or lift spring.
Inlet pressure excessive.
Viscosity of fluid too high.
Valve not installed on fluid, voltage, or pressure specified.
1.
2.
3.
4.
5.
6.
7.
8.
9.
WILL NOT CLOSE
Cylinder cap tube bent or dented.
Back pressure greater than inlet.
Foreign matter in valve.
Seat screw worn or damaged.
Disc worn or damaged.
Piston rings (if used) distorted.
Broken or missing spring.
Viscosity of fluid too high.
Valve not installed on fluid, voltage, or pressure specified.
Normally Closed Valve Operation
This type remains in the closed position when the coil is de-energized. Energizing the coil raises the
plunger, which slides up the stem of the plunger assembly. The impact as it strikes the stem cap raises the
plunger off the seat and opens the valve.
When the coil is de-energized, the plunger assembly drops onto the seat, and closes off the flow. Gravity
and line pressure keep the valve closed. In some valves, a return spring mounted on top of the plunger may
assist in closing the valve.
High pressure Sample Sentry® units have double-wound (3-wire) coil and relay for operation. Maximum
cycle rate for relay-operated valves is 10 per minute. The operating principle of the valves is the same
whether equipped with the standard 2-wire coil or the 3-wire coil.
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
39
SPD 1.1.9 Rev. 2
Sample Sentry®
DRAWINGS
12-03252A
Sample Sentry® assembly with VREL and solenoid valves
12-03252B
Needle drive assembly with metering valve
12-03252F
Power supply board assembly
12-03252K
Flow meter assembly
Sentry Equipment Corp. Π856 E. Armour Road ΠP.O. Box 127 ΠOconomowoc, WI 53066 Π262/567-7256 ΠFAX: 262/567-4523
Web: www.sentry-equip. com Πe-mail: sales@sentry-equip.com
40