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Cameron 288A User Manual

Differential pressure indicating switch
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Contents
Safety ............................................................................................................ 2
Section 1-Introduction ................................................................................. 3
General ......................................................................................................... 3
Main Components ......................................................................................... 3
Indicating Switch ...................................................................................... 4
Relays ....................................................................................................... 5
Wiring ........................................................................................................ 5
Diff erential Pressure Unit (DPU) ............................................................... 5
Specifi cations ............................................................................................... 5
Nuclear Qualifi cations ............................................................................... 6
Section 2-Installation ................................................................................... 7
General ......................................................................................................... 7
Mounting/Piping/DPU Installation ................................................................. 7
Electrical Connection (Switches/Relays) ...................................................... 7
Switch Use .................................................................................................... 7
Startup .......................................................................................................... 8
Switch and Relay Wiring Diagrams............................................................... 9
Section 3-Maintenance and Calibration ................................................... 14
Tools............................................................................................................ 14
Bezel/Lens (or Cover) Installation and Removal......................................... 14
Calibration Check........................................................................................ 15
Pointer Installation and Removal ................................................................ 16
Pointer Installation .................................................................................. 16
Pointer Removal ...................................................................................... 16
Indicator Calibration .................................................................................... 17
Drive Arm Tightness Test ......................................................................... 19
Drive Arm Stop Adjustment .................................................................... 20
Switch Calibration ..................................................................................... 20
Calibration Setup ..................................................................................... 20
Calibration Procedure ............................................................................. 21
Changing Switch Set Point ........................................................................ 22
Defi nitions of Terms ................................................................................. 22
BARTON NUCLEAR MODEL 288A
DIFFERENTIAL PRESSURE
INDICATING SWITCH
User Manual
Part No. 9A-C10301, Rev. 08
AUGUST 2021

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  • Page 1: Table Of Contents

    BARTON NUCLEAR MODEL 288A DIFFERENTIAL PRESSURE INDICATING SWITCH User Manual Part No. 9A-C10301, Rev. 08 AUGUST 2021 Contents Safety ......................2 Section 1—Introduction ................. 3 General ......................3 Main Components ..................3 Indicating Switch ..................4 Relays ....................... 5 Wiring ......................5 Diff...

  • Page 2: Safety

    Best Practices for Set Points ..............22 Changing Set Point of an In-Service Instrument ........23 Changing Set Point of an Out-of-Service Instrument ......24 Range Changes ..................24 Parts Replacement...................25 Troubleshooting ..................26 Section 4—Assembly Drawing and Parts Lists ........28 Section 5—Dimensional Drawings ............

  • Page 3: Section 1-Introduction

    Section 1 Section 1—Introduction General The Barton* weatherproof Model 288A is a diff erential pressure indicating switch. The Model 288A has a NEMA-4 watertight die-cast aluminum case (fi nished with a weather-resistant black epoxy resin paint). The cover lens is secured in the bezel with an elastomer ring to reduce the possibility of acci- dental breakage.

  • Page 4: Indicating Switch

    Section 1 Model 288A Differential Pressure Indicating Switch Indicating Switch (refer to Figure 1.2, Figures 2.1 to 2.6, and Table 2.1) Rotation of the DPU torque tube shaft is coupled through connecting linkage within the switch case to move the pointer across the scale plate. An actuat- ing cam, directly connected to the torque tube shaft, rotates with the motion of the shaft.

  • Page 5: Relays

    Model 288A Differential Pressure Indicating Switch Section 1 Standard models can have one or two alarm switches. Each switch can be connected to operate normally-opened or normally-closed. The direct-set switch contacts are adjustable over a scale range of 5-95% nominal.

  • Page 6: Nuclear Qualifi Cations

    DPDT ..........±6% of full scale DP (max) Accuracy of Repeatability ....±0.25% of full scale DP Nuclear Qualifi cations The following nuclear qualifi cation applications are based on Cameron Engineering Report 9A-CR3-288A-13 and 50277306-C-0000193 with switch chatter sensitivity ad- dressed in Cameron Engineering Report 9A-CR3-288A-19: •...

  • Page 7: Section 2-Installation

    Model 288A Differential Pressure Indicating Switch Section 2 Section 2—Installation General The instrument should be inspected at time of unpacking to detect any dam- age that may have occurred during shipment. IMPORTANT: The DPU was checked for accuracy at the factory. Do not change any of the settings during examination or accuracy could be aff...

  • Page 8: Startup

    Section 2 Model 288A Differential Pressure Indicating Switch IMPORTANT: Arc suppression for inductive loads will prolong the life of the switch contacts. IMPORTANT: Due to their size, subminiature switches have small mechanical clear- ances; therefore, no rating above 250 VAC has been established.

  • Page 9: Switch And Relay Wiring Diagrams

    Model 288A Differential Pressure Indicating Switch Section 2 Switch and Relay Wiring Diagrams IMPORTANT: Figures 2.1 through 2.6 show: switch & relay contacts in the relaxed (shelf) condition, the low switch set to trip at a position below the pointer scale position, and the high switch set to trip at a position above the pointer scale position.
  • Page 10 Section 2 Model 288A Differential Pressure Indicating Switch Figure 2.2—Low/high DPDT switch diagrams (current confi guration color codes - see Table 2.1, page 8)
  • Page 11 Model 288A Differential Pressure Indicating Switch Section 2 Figure 2.3—3-switch diagram (current confi guration color codes - see Table 2.1, page 8) Figure 2.4—4-switch diagram (3 or 4 independently adjustable switches) (current confi guration color codes - see Table 2.1, page 8)
  • Page 12 Section 2 Model 288A Differential Pressure Indicating Switch Figure 2.5—Low/high switch(es) w/SPDT relay(s) diagrams (current confi guration color codes - see Table 2.1, page 8)
  • Page 13 Model 288A Differential Pressure Indicating Switch Section 2 Figure 2.6—Low/high switch(es) w/DPDT relay(s) diagrams (current confi guration color codes - see Table 2.1, page 8)

  • Page 14: Section 3-Maintenance And Calibration

    Section 3 Model 288A Differential Pressure Indicating Switch Section 3—Maintenance and Calibration The following checks are recommended for preventive maintenance: • Periodically inspect alarm switch mechanism to verify that all mounting screws are seated properly. • Inspect linkage for wear.

  • Page 15: Calibration Check

    Model 288A Differential Pressure Indicating Switch Section 3 Figure 3.1—Bezel and lens cover IMPORTANT: Ensure the bezel gasket is properly oriented before placing the instru- ment back in service. Incorrect gasket orientation will cause the instru- ment indicator to jam, resulting in inaccurate readings.

  • Page 16: Pointer Installation And Removal

    Section 3 Model 288A Differential Pressure Indicating Switch 3. To test for reverse travel, connect the pressure source to the LP housing and vent the HP housing. Apply pressures approximately 150% of the DP range. The pointer should move approximately 5% to 10% below zero.

  • Page 17: Indicator Calibration

    Model 288A Differential Pressure Indicating Switch Section 3 2. Gently turn the knurled head of the screw clockwise, pushing the pin against the movement shaft and lifting the pointer with the arms. Finger pressure should be suffi cient to pull the pointer free. If more pressure is required, an Allen wrench (inserted into head of the screw) can be used.
  • Page 18 Section 3 Model 288A Differential Pressure Indicating Switch 4. Check the pointer for zero indication. If necessary, set the pointer to zero by slipping the pointer on the hub, per Calibration Check, step 2, page 5. Apply 100% pressure. If the pointer exceeds full-scale, lengthen the movement range arm by adjusting the range adjust screw with a 1/8-in.

  • Page 19: Drive Arm Tightness Test

    Model 288A Differential Pressure Indicating Switch Section 3 2). The range arm is slipped by applying pressure to the range arm with thumb, while holding the gear fi rmly in place. Retest the pointer response at 50%, 0%, and 100% of full-scale diff erential pressure, and adjust the linkage until the readings are acceptable.

  • Page 20: Drive Arm Stop Adjustment

    Section 3 Model 288A Differential Pressure Indicating Switch Drive Arm Stop Adjustment 1. Apply suffi cient pressure to the high-pressure housing to defl ect the pointer against the full range stop snubber on the scale plate. 2. Slide the upper drive arm stop bracket against the drive arm and tighten the drive arm stop bracket screw.

  • Page 21: Calibration Procedure

    Model 288A Differential Pressure Indicating Switch Section 3 3. Unlock the switch plate and move the plate until the roller is positioned at the top of the cam. 4. Advance the plunger screw until the switch activates, then advance the plunger screw an additional 60°...

  • Page 22: Changing Switch Set Point

    Section 3 Model 288A Differential Pressure Indicating Switch 7. If the switch is to be fi eld-set at low diff erential pressure values (1% or 2% of pressure range), check the crank to prevent a top-dead-center posi- tion. Otherwise, the minimum set point position will be restricted and the set point may become reversed.

  • Page 23: Changing Set Point Of An In-Service Instrument

    Model 288A Differential Pressure Indicating Switch Section 3 itself. For example, the high switch (right side of scale) may be set at full scale, but should not be set near zero. The low switch may be set at zero, but should not be set near full scale. (Observe deadband values for specifi...

  • Page 24: Changing Set Point Of An Out-Of-Service Instrument

    Section 3 Model 288A Differential Pressure Indicating Switch IMPORTANT: The switch index has 10 divisions, marked 0, 5, and 10. These match the markings on the outer edge of the scale. Example: Scale has range of 0-60 psid. Set point is 24 psid, with decreasing pressure, (24/60 x 10 = 4).

  • Page 25: Parts Replacement

    Drive Arm and Switch & Plate Assemblies have been redesigned. These assemblies are not backwards compatible and have to be installed at the same time for proper operation of the Model 288A. Drive Arm and Switch & Plate Assemblies 1.

  • Page 26: Troubleshooting

    Section 3 Model 288A Differential Pressure Indicating Switch Troubleshooting For indicating switch troubleshooting tips, see Table 3.2 below. For informa- tion related to the Model 224 DPU, see Table A.3, page A-15. Table 3.2—Troubleshooting Tips Problem Possible Probable Cause Corrective...
  • Page 27 Model 288A Differential Pressure Indicating Switch Section 3 Table 3.2—Troubleshooting Tips Problem Possible Probable Cause Corrective Source Action Switch Calibration Failure to check set point after locking Verify set point Drifts Techniques repeatability after (set point locking switch plate not repeat-...

  • Page 28: Section 4-Assembly Drawing And Parts Lists

    Section 4 Model 288A Differential Pressure Indicating Switch Section 4—Assembly Drawing and Parts Lists Figure 4.1—Model 288A...
  • Page 29 Model 288A Differential Pressure Indicating Switch Section 4 Table 4.1—Parts List, Model 288A Indicating Switch Item Description Part No. Per Unit Diff erential Pressure Unit (not shown) See Appendix A Case Assembly 1/2 NPT Conduit 9A-C0288-0038B 3/4 NPT Conduit 9A-CS666-0050Z...
  • Page 30 Section 4 Model 288A Differential Pressure Indicating Switch Table 4.1—Parts List, Model 288A Indicating Switch Item Description Part No. Per Unit Screw, Bezel 9A-C0181-0007C Screw, Flat, Skt Cap, 10-32 x 1/2, SST (Riser/ 9A-C0240-0019J DPU) Spacer, DPU to case 9A-C0224-1547C...
  • Page 31 Model 288A Differential Pressure Indicating Switch Section 4 Table 4.1—Parts List, Model 288A Indicating Switch Item Description Part No. Per Unit Switch and Plate Assembly: (Tefzel Insulation-Radiation Resistant) see also item 26 High, SPDT 9A-CS666-1201B-N High DPDT 9A-CS401-0185B-N High Relay...
  • Page 32 Section 4 Model 288A Differential Pressure Indicating Switch Table 4.1—Parts List, Model 288A Indicating Switch Item Description Part No. Per Unit Washer, Flat, #3, SST (5 per switch) 9A-C0003-0045K Bezel Assembly (Bezel, Lens Cover, and Gasket) 9A-C0277-0018B Bezel (part of 9A-C0277-0018B)
  • Page 33 Model 288A Differential Pressure Indicating Switch Section 4 Table 4.1—Parts List, Model 288A Indicating Switch Item Description Part No. Per Unit Screw, Strap Hole Filler (if switch is not installed, 9A-C0119-0042J 1 per switch, not shown) Calibration Kit (not shown)

  • Page 34: Section 5-Dimensional Drawings

    Section 5 Model 288A Differential Pressure Indicating Switch S ection 5—Dimensional Drawings IMPORTANT: For DPU dimensional information, refer to DPU Dimensional Drawings, page A-19. Figure 5.1—Model 288A, rear view Pressure Housing Dim. A Dim. B Dim. C Dim. D Pressure Connection...
  • Page 35 Model 288A Differential Pressure Indicating Switch Section 5 Figure 5.2—Model 288A, side view (see table in Figure 5.1, page 34, for Dim. A measurements) Figure 5.3—Model 288A, front view...

  • Page 36: Appendix A-Model 224 Dpu

    Model 224 Differential Pressure Unit Appendix A Appendix A—Model 224 DPU DPU Description The Barton Model 224 Diff erential Pressure Unit (DPU) is a mechanical device that measures diff erential pressure relative to a gas or liquid fl owing through a process system, or to the level of a liquid contained in a process vessel.
  • Page 37 Appendix A Model 224 Differential Pressure Unit The BUA with 3/4-inch bellows accommodates diff erential pressures up to 400 psi. The range springs are grouped around the outside of the bellows and must be of a material that is compatible with the liquid being measured. The BUA with 5/8-inch bellows accommodates diff...

  • Page 38: Theory Of Operation

    Model 224 Differential Pressure Unit Appendix A Table A.1—Model 224 DPU Specifi cations BODY AVAILABLE DIFFERENTIAL PRESSURE RANGES Stainless Steel/Inconel Bellows Inconel Bellows psi (bar) Housing Material 1-5/8" (41.3 mm) O.D. 3/4" (19.1 mm) O.D. 5/8" (15.9 mm) O.D. Stainless Steel (316) 0-30"...

  • Page 39: Dpu Installation

    Appendix A Model 224 Differential Pressure Unit F igure A.2—Model 224 DPU components required to actuate process instruments, such as recorders, indicators, trans- mitters, controllers, and switches. If the bellows are subjected to a pressure greater than the range of the DPU, they move their normal travel range and a small amount of overtravel until the overrange valve seals against the valve seat.

  • Page 40: Mounting

    Model 224 Differential Pressure Unit Appendix A For applications requiring special cleaning/precautions, a polyethylene bag is used to protect the instrument from contamination. Remove this bag only under conditions of extreme cleanliness. Mounting Mount the instrument to a solid support with four 5/16-inch (8 mm) grade 5 or better bolts, and apply 17 ft-lb of torque.

  • Page 41: Piping Diagrams

    Appendix A Model 224 Differential Pressure Unit • Mount the DPU on a solid support to minimize vibration. Tighten all points, using a suitable sealant compound; leaks in piping can cause measurement errors. • Rotate the housing as necessary to place the pressure connection in the proper position.
  • Page 42 Model 224 Differential Pressure Unit Appendix A Figure A.5—Gas Flow, Hydrates Present Figure A.6—Steam Flow, DPU Below Run Figure A.7— Liquid Flow, DPU Above Run...
  • Page 43 Appendix A Model 224 Differential Pressure Unit Figure A.8—Liquid Flow, DPU Below Run Figure A.9—Corrosive Liquid Flow Figure A.10—Cool Non-Condensing Liquid, DPU Level with Tank Bottom...
  • Page 44 Model 224 Differential Pressure Unit Appendix A Figure A.11—Cool Non-Condensing Liquid, DPU Below Tank Figure A.12—DPU Bottom Tank with Reference Leg...
  • Page 45 Appendix A Model 224 Differential Pressure Unit Figure A.13—Liquid CO2 Figure A.14—Cryogenic Liquids A-10...
  • Page 46 Model 224 Differential Pressure Unit Appendix A Figure A.15—Bubbler System Figure A.16—Liquid Specifi c Gravity A-11...

  • Page 47: Startup

    If the instrument is used in services where solids or semi-solids may accumu- late inside the pressure housings, periodically inspect and clean the DPU. See DPU Cleaning and Inspection below. For calibration procedures for the Model 288A Diff erential Pressure Indicat- ing Switch, see Section 3. Required Tools A screwdriver is needed for adjusting screws in the mounting bracket, and a 50-lb torque wrench is recommended for adjusting pressure housing bolts.

  • Page 48: Dpu Cleaning/Inspection Procedure

    Model 224 Differential Pressure Unit Appendix A WARNING: The unexpected release of internal pressure from a DPU can result in severe personal injury, death or property damage. Before remov- ing DPU housing bolts, perform a pressure check. This is especially im- portant if the DPU is installed in a gas application with working pressures exceeding 200 psig.

  • Page 49: Changing The Dpu Range

    Notes: (1) Lubricant: Molykote G paste, graphite-base grease, or similar lubricants. Lube fi rst thread only. (2) Torque on bolts is accomplished in 3 or 4 steps. Tighten uniformly. (3) Cameron recommends using a torque wrench whenever installing housing bolts. Rotation of bolt head is measured after bolt is "snug"...

  • Page 50: Dpu Troubleshooting

    Table A.3 provides a description of commonly reported problems, probable causes, and corrective actions for use in troubleshooting issues involving the Model 224 DPU. See Table 3.2, page 27, for Model 288A Diff erential Indicating Switch trouble- shooting information. Table A.3—Troubleshooting Tips...
  • Page 51 Appendix A Model 224 Differential Pressure Unit Table A.3—Troubleshooting Tips Problem Possible Probable Cause Corrective Action Source Low or No Bellows Unit Housing fi lled with solids restricting bel- Clean out housing Indication lows movement Gas (liquid service) or liquid (gas service) Vent housing trapped in housing High pressure housing gasket leaks...

  • Page 52: Dpu Assembly Drawing And Parts List

    Model 224 Differential Pressure Unit Appendix A DPU Assembly Drawing and Parts List Figure A.17—Model 224 DPU assembly drawing A-17...
  • Page 53 Appendix A Model 224 Differential Pressure Unit Table A.4—Model 224 DPU Parts List Item Description Part No. Bellows Unit Assembly, 3/4" or 5/8" Bellows Unit Assembly, 1-5/8" O-Ring, Housing Gasket Viton 9A-C0001-0039R 9A-C0001-1054R Bracket, Mounting 9A-C0273-0001C Washer, ET Lock, 1/4" SST 9A-C0003-0068K Screw, Hex Hd.

  • Page 54: Dpu Dimensional Drawings

    Model 224 Differential Pressure Unit Appendix A DPU Dimensional Drawings Figure A.18—Model 224 DPU dimensional drawing Table A.5—Model 224 DPU Dimensions Dim "A" Dim "B" DIM "C" DIM "D" DIM "E" (psi) in. (mm) in. (mm) in. (mm) in. (mm) in.
  • Page 55 Cameron agrees to repair or furnish a replacement for, but not install, any product which within one (1) year from the date of shipment by Cameron shall, upon test and examina- tion by Cameron, prove defective within the above warranty.

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