Model Y/11DM Pneumatic Differential Pressure ... - Yokogawa

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A-1Appendix 1. 80A Pneumatic Amplifier(Part No. F9138YA)The function of the pneumatic amplifier is toconvert a small change in the input signal (anair pressure signal) to a large change in theoutput signal. Typically a 0.07 kgf/cm 2 (0.07 bar,7 kPa, or 1 psi) change in the input will produceapproximately a 0.8 kgf/cm 2 (0.8 bar, 80 kPa, or 12psi) change in the output.A1.1 Principles of OperationThe air supply enters the pneumatic amplifierthrough a port on the surface of the instrument onwhich the amplifier is mounted. The input signal(nozzle pressure) enters the amplifier throughanother port and acts on the diaphragm. Since thestem valve is mounted on the diaphragm, the twomove in unison.As the input signal increases, the stem pushesagainst a ball valve which in turn moves a flatspring, allowing the supply air to enter the amplifierbody. Further motion of the stem valve, causes itto close off the exhaust port. Thus, when the inputpressure increases, the stem (exhaust) valvecloses and the supply valve opens; when the inputdecreases, the stem valve opens and the supplyvalve closes. This varies the pressure to the output.Flat springmounting screwA1.2 Cleaning the PneumaticAmplifierShould the pneumatic amplifier require cleaning,remove it from the instrument. Loosen the twocover screws and the spring mounting screw todisassemble the pneumatic amplifier. Clean thedisassembled parts with a suitable solvent (do notallow solvent to contact the gasket) and dry themcarefully with compressed air. When reassemblingthe pneumatic amplifier, all corresponding holesmust line up and all outside edges must coincidewith other edge of the amplifier body casting.Tighten all screws.CoverscrewCoverFigure A2.GasketDiaphragmBodyExploded ViewCAUTIONBallFlat spring Flat springmounting screwF002.aiInputBall valveSupply airOutputExhaustDiaphragmFlat springExhaust valveStem valveSupply air valveAfter reassembling the amplifier, perform acalibration with the calibrator. (Refer to sectionA1.3)Tension adjustmentF001.aiFigure A1.Cross Sectional ViewIM02C01B06-01E
A-2A1.3 Calibration Procedure usingCalibrating FixtureThis procedure requires a Model 6971 calibrator,which is available from Yokogawa.(1) Mount the amplifier on the calibrator with theflat spring mounting screw to the left. (Be sureto mount the amplifier in the correct direction.)Fasten the amplifier with the two wing nuts.(2) Air supply.Apply air at 1.4 kgf/cm 2 or bar, 140 kPa, or20 psi to air supply coupling 2 .(3) Self-centering the stem valve.a. Seal nozzle 3 by manual contact forseveral seconds, until the nozzle pressure(diaphragm back-up pressure) is 1.4 kgf/cm 2or bar, 140 kPa, or 20 psi and confirm thatthe nozzle pressure exceeds 1.0 kgf/cm 2 orbar, 100 kPa, or 15 psi.b. Open nozzle 3 and manually close the aircheck valve, until the nozzle input pressure iszero (atmospheric pressure).c. Repeat steps a and b above.(4) Nozzle input pressure adjustment.Turn nozzle 3 with a wrench while observingnozzle input pressure gauge 5 , so the nozzleinput pressure is 0.25 kgf/cm 2 or bar, 25 kPa, or3.6 psi.(5) Output pressure confirmation.Read the output pressure on output pressureindicator 6 . When output pressure fallsbetween 0.55 and 0.60 kgf/cm 2 (0.55 and 0.60bar, 55 and 60 kPa, or 7.8 and 8.5 psi), applyair pressure at 0 and 1.4 kgf/cm 2 (0 and 1.4 bar,0 and 140 kPa, or 0 and 20 psi) by one cyclethe same as step (2). Next, confirm that outputpressure falls between 0.55 and 0.60 kgf/cm 2(0.55 and 0.60 bar, 55 and 60 kPa, or 7.8 and8.5 psi) under the same condition as step(4). When the output pressure falls within thisrange, output adjustment is completed, but if itdoes not, perform output pressure adjustmentas per step (6).(6) Output pressure adjustment.a. Close the air supply valve.b. Remove plug 9 using a 3/16" Allen wrench.c. Insert a screwdriver in the plug hole and turnthe tension adjustment (turn it clockwise todecrease output, and counterclockwise toincrease output).d. Install plug 9 .e. Repeat steps (2) through (6).Air checkvalveNozzleSupply aircouplingWrenchPlugFigure A3.Nozzle inputpressure gaugeFront viewRear viewOutput pressuregaugeModel 6971 Pneumatic AmplifierCalibratorAmplifiermounting studsF003.aiAir checkvalveKnobSupply aircouplingF004.aiNOTE: The above amplifier output pressureadjustment can be performed by removingthe amplifier from the calibrator.IM02C01B06-01E
Page 3 and 4: iiAppendix 1.5.9.1 Dashpot Removal.
Page 5 and 6: 1-21.1 Safety PrecautionsWARNING•
Page 7 and 8: 2.3 Standard SpecificationsSpan Lim
Page 9 and 10: 2-42.6 Dimensions118Allow clearance
Page 11: 4. Operation4.1 Zero Adjustment4.1.
Page 14 and 15: 5-35.1.3 To Change Range of Transmi
Page 16 and 17: 5-55.4 To Clean Nozzle AssemblyAn a
Page 18: 5-75.9 Further DisassemblyIMPORTANT
Page 21: 5-105.9.10 Flapper AlignmentThe fla
Page 25 and 26: 2Nov. 2012Subject to change without
Page 27: 4Item Part No. Qty DescriptionInteg

Model Y/11DM Pneumatic Differential Pressure ... - Yokogawa

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