DIGITAL PRESSURE INDICATORS

Transcription

1 TECHNICAL MANUAL MP-155 INSTRUMENT CALIBRATION PROCEDURE DIGITAL PRESSURE INDICATORS THIS PUBLICATION SUPERSEDES NAVAIR 17-20MP-155 DATED 1 MARCH 2002 DISTRIBUTION STATEMENT C. DISTRIBUTION AUTHORIZED TO U.S. GOVERNMENT AGENCIES AND THEIR CONTRACTORS TO PROTECT PUBLICATIONS REQUIRED FOR OFFICIAL USE OR FOR ADMINISTRATIVE OR OPERATIONAL PURPOSES ONLY. OTHER REQUESTS FOR THIS DOCUMENT SHALL BE REFERRED TO MEASUREMENT SCIENCE DEPARTMENT, CORONA DIVISION, NAVAL SURFACE WARFARE CENTER, P.O. BOX 5000, CORONA, CA MP-155 DESTRUCTION NOTICE - FOR UNCLASSIFIED, LIMITED DOCUMENTS, DESTROY BY ANY METHOD THAT WILL PREVENT DISCLOSURE OF CONTENTS OR RECONSTRUCTION OF THE DOCUMENT. PUBLISHED BY DIRECTION OF COMMANDER NAVAL AIR SYSTEMS COMMAND 1 JULY 2005

2 LIST OF EFFECTIVE PAGES The purpose of this list is to identify the pages in this document affected by any technical content changes made since the previous release of the document. : On a revised page, with the exception of the Title, the A, and the i pages, the technical changes are indicated by a vertical line in the outer margin of the page. Page No. ** Revision* Page No. ** Revision* Page No. ** Revision* Title 0 A 0 i 0 1 to A-1 0 B-1 0 *Zero in this column indicates an original page. R in this column indicates a revised page. **All pages not listed are blank pages. A

3 TABLE OF CONTENTS Section Page 1 Introduction and Description Equipment Requirements Preliminary Operations Calibration Process Pressure Indication Tests Using the Hydraulic DWT - Item Pressure Indication Tests Using the Pneumatic DWT - Item Pressure Indication Tests Using the PPS APC/PPS System Shut Down Navy Calibration Checklist Appendix A: Representative Test Instruments... A-1 Appendix B: Pressure Unit Conversion Factors... B-1 ILLUSTRATIONS Figure Page 1 Pressure Indication Test Setup No Pressure Indication Test Setup No Pressure Indication Test Setup No TABLES Table Page 1 Calibration Description Equipment Requirements... 2 i

4 SECTION 1 INTRODUCTION AND DESCRIPTION 1.1 This procedure describes the calibration of the Digital Pressure Indicators with any given pressure range from 0 to 5 psi up to 0 to 10,000 psi or as given in Table 1. Digital pressure indicators that may be calibrated using this procedure include, but are not limited to, the models and series listed in Appendix A. The instrument being calibrated is referred to herein as the TI (Test Instrument). 1.2 All comments concerning this procedure should be directed to the Measurement Science Department, Corona Division, Naval Surface Warfare Center, P.O. Box 5000, Corona, CA This procedure includes tests of essential performance parameters only. Any malfunction noticed during calibration, whether specifically tested for or not, should be corrected. TI Characteristics Pressure indication Table 1. Calibration Description Performance Specifications Ranges: 0 up to 10,000 psi 0 up to 3,000 in H 2 O 0 up to 300 in Hg 0 up to 10,000 mm Hg 0 up to 200 M Pa 0 up to 10,000 mb 0 up to 10,000 cm H 2 O 0 up to 10,000 mm H 2 O Tolerance: ±0.035% up to ±0.1% of range span, according to TI model Test Method Comparison to the true pressure generated by a dead weight tester of an appropriate pressure range. Alternatively (710A only), comparison to a precision pressure standard, using an automatic pressure calibrator and intensifier unit to control the pressure. SECTION 2 EQUIPMENT REQUIREMENTS S Minimum use specifications are the principal parameters required for performance of the calibration, and are included to assist in the selection of alternate equipment, which may be used at the discretion of the using laboratory. Satisfactory performance of alternate items shall be verified prior to use. All applicable equipment must bear evidence of current calibration. The instruments utilized in this procedure were selected from those known to be available at Navy calibration facilities, and the listing by make or model number carries no implication of preference, recommendation, or approval for use by other agencies. It is recognized that equivalent equipment produced by other manufacturers may be capable of equally satisfactory performance in this procedure. 1

5 Item 2.1 Dead weight tester (DWT) system Required components: Dead weight gauge with pistons and weights Table 2. Equipment Requirements Minimum Use Specifications See Required Components Range: 6 to 10,000 psi Uncertainty: ±0.01% iv or ±0.01 psi, whichever is greater Calibration Equipment Ruska Instrument Ruska Instrument Hydraulic hand pump To provide control of hydraulic pressure Ruska Instrument Reservoir pump To provide sufficient oil for test Ruska Instrument Filter To keep oil clean Ruska Instrument Connector block To connect a hydraulic TI to dead weight tester system Reference manometer To provide a reference pressure point at atmosphere Differential pressure null indicator To determine when hydraulic and pneumatic pressures are balanced at the differential pressure cell Differential pressure cell To provide a seal between the fluid and pneumatic pressures Ruska Instrument Ruska Instrument Ruska Instrument Ruska Instrument Pneumatic hand pump To provide fine control of pneumatic pressure Ruska Instrument Connector block To connect a pneumatic TI dead weight tester system Pneumatic pressure intensifier To intensify pressure from item 2.1 up to 10,000 psig Ruska Instrument Ruska Instrument Table To mount equipment Ruska Instrument Item 2.1 is required for a TI indicating above 600 psig, while item 2.2 is required for a TI with a maximum indication of 600 psig (or equivalent pressure in other units) or less. 2.2 Dead weight tester (DWT) See Required Components Ruska Instrument Required Components: Piston-cylinder assembly Piston-cylinder assembly Range: 0.2 to 15 psi Uncertainty: ±0.01% iv or ± psi, whichever is greater Range: 2 to 600 psi Uncertainty: ±0.01% iv or ± psi, whichever is greater Ruska Instrument Ruska Instrument Control pack To control pressure to TI and item 2.2 Ruska Instrument Nitrogen source Nitrogen, Military Specification MIL-PRF-27401*, Type 1, Grade A, 99.5% pure Local supply 2

6 Item Minimum Use Specifications Calibration Equipment Items 2.4 and 2.5 may be utilized instead of items 2.1 through if the TI is the 710A due to limitations of the calibration equipment. 2.4 Precision pressure standard (PPS) 2.5 Automatic pressure calibrator (APC) Range: 0 to 10,000 psi Uncertainty: ±0.025% iv or ±0.002 in Hg, whichever is greater Range: 0 to 10,000 psi Uncertainty: NA King Nutronics 3689A King Nutronics K3 Required Components: Intensifier Range: 0 to 10,000 psi Uncertainty: N/A Control unit Range: 0 to 10,000 psi Uncertainty: N/A Accessory case assembly Required components: Liquid trap (2 required) King Nutronics King Nutronics Container for accessories King Nutronics Max operating pressure: 10,000 psig Proof pressure: 15,000 psig 2.6 Pressure hose Max operating pressure: 10,000 psig Proof pressure: 15,000 psig 2.7 Pressure fittings and adapters High pressure quick disconnect Max operating pressure: 10,000 psig Proof pressure: 15,000 psig 2.8 Hydraulic pressure gauge Range: 0 to 1,000 psi or 0 to 3,000 psi Uncertainty: NA 2.9 Pressure regulator Min inlet pressure: 2,000 psig Outlet pressure: 1,000 psig Max Outlet resolution: 100 psig King Nutronics Local supply Local supply Local supply Standard Pneumatic Engineering LC-G2-CGA580 or Local supply 2.10 Cleaning solvent HCFC-141b Allied Signal Genesolv 2000; or other SYSCOM-approved gauge cleaning solvent 2.11 Commercial item description* Reference data; applies to non-oxygen system; follow all safety precautions in this document and in Material Safety Data Sheet for item 2.10 *It is the user s responsibility to ensure conformance to the latest issue of the reference document. Commercial Item Description A-A-50427: Cleaning Compound, Solvent, 1, 1-dichloro-1-fluoroethane, HCFC-141b, for Oxygen Systems, June 26,

7 SECTION 3 PRELIMINARY OPERATIONS WARNINGS THIS PROCEDURE INVOLVES PRESSURES THAT ARE HAZARDOUS TO PERSONNEL. USE ONLY APPROVED PRESSURE HOSES AND FITTINGS. USE EXTREME CAUTION WHEN USING HCFC-141B SINCE ITS PERMISSIBLE EXPOSURE LIMIT (PEL) IS ONLY HALF THAT OF TRICHLOROTRIFLUOROETHANE (FREON), MAKING IT TWICE AS TOXIC. OBSERVE THE SAFETY PRECAUTIONS AND HANDLING PROCEDURES OUTLINED IN ITEM 2.13 WHEN USING HCFC-141B. USE LOCAL EXHAUST AT FILLING ZONES AND WHERE GAUGE CLEANING OCCURS. USE GENERAL VENTILATION FOR STORAGE AREAS. REVIEW THE MATERIAL SAFETY DATA SHEET FOR HCFC-141B FOR ADDITIONAL DETAILS. Select the dead weight tester (item 2.1 or 2.2) that provides the most accurate and efficient TI calibration over the TI pressure range. The dead weight tester will be referred to as the DWT in this procedure. 3.1 Ensure that the TI is clean and free from defects that would impair its operation. Wipe excessive oil or grease from the TI, using a clean cloth and cleaning solvent (item 2.10) as required. 3.2 If applicable, ensure that the pneumatic side of the dead weight tester system (item 2.1) is completely free from oil or grease. Wipe with a clean cloth, using cleaning solvent to remove all visible oil spots or stains. 3.3 The checklists provided at the end of this procedure are representative of the type of TIs that can be covered by this procedure. For TIs without a checklist, select the calibration points as described below and record the selected calibration points in column (2) of the new checklist Select ten equally spaced points over the range of the TI, from 10% to 100% of the maximum TI indication Record the values listed in the preceding step, except for the highest value, in a decreasing order for the decreasing pressure tests. 3.4 Compute the pressures to be generated using the high or low range piston, weight adapter and weights that come as close as possible to the calibration points on the TI checklist, or to the points or values selected in step

8 3.5 Compute the required true pressure values using the following equation: P = M(g Ao (1 + bp ) [1 + (α + α ) (t 25)] p K L ) c = M(g Ao (1 + bp ) [1 + (α p K L ) + α ) (t 25)] c where P = True pressure, psig M = Combined mass of piston, weight adapter, and weights applied, lbs g L = Local gravity, gals A O = Effective piston area at 25 C and atmospheric pressure, in 2. (from Report of Calibration) b = Change in piston area due to elastic distortion under pressure, N/psig, where N is a dimensionless number P P = Selected pressure, psig α K = Co-efficient of thermal expansion of piston, (in 2 / in 2 )/ C α C = Co-efficient of thermal expansion of cylinder, (in 2 / in 2 )/ C t = Test temperature ( C) = Air Buoyancy Correction = 1 ρ air = Density of air, gm/cm 3 ρ brass = Density of brass, gm/cm 3 ρ ρ air brass = S Some Reports of Calibration will provide A o at 23 C instead of 25 C. If so, use (t 23) in the equation instead of (t 25). Also, the coefficient of the piston and cylinder combined, α, may be reported instead of separately as α K and α C. If the value of local gravity is unknown, compute the approximate value by using the formula: g L = sin 2 φ sin 2 2φ a where g L = local gravity in gals, absolute system φ = latitude in degrees and minutes a = elevation in feet above sea level 3.6 Record the true pressure values computed in step 3.5 in column (3) on the calibration checklist. Convert the values to the TI units using Appendix B, as necessary. Connect the TI to an appropriate source; allow 10 minutes for warm-up. If the TI is a Wallace and Tiernan model, allow 1 hour for thermal stabilization. 3.7 If item 2.1 is to be used connect the equipment as shown in Figure 1. If item 2.2 is to be used as the DWT, skip to step If item 2.4 is selected to calibrate a 710A series TI, skip directly to step

9 VALVE # RESERVOIR PUMP DIFFERENTIAL PRESSURE NULL INDICATOR TI (SIDE VIEW) VALVE #1 VALVE #3 VALVE #4 TEST POINT A OIL VALVE #5 VALVE #6 VALVE #7 VALVE #8 VALVE # DEAD WEIGHT GAUGE HYDRAULIC HAND PUMP FILTER CONNECTOR BLOCK REFERENCE MANOMETER DIFFERENTIAL PRESSURE CELL PNEUMATIC HAND PUMP CONNECTOR BLOCK 2.9 PRESSURE REGULATOR PNEUMATIC PRESSURE INTENSIFIER 2.3 NITROGEN SOURCE Figure 1. Pressure Indication Test Setup No. 1 S Install a cap or plug (item 2.7) in the connector block at Test Point A, Oil. The TI is connected to the connector block at Test Point B, Gas, using a pressure hose (item 2.6) and adapter (item 2.7) as required. Valve No. 8 vents to the atmosphere. 3.8 Ensure that the applicable DWT components are connected to an appropriate power source with the power switches set to off. 3.9 Purge the hydraulic side of the DWT system of any air as follows: Open valve No 2; ensure that valves No. 1, 3, 4, 5 and 6 are closed. Install a hydraulic pressure gauge (item 2.8) at Test Point A Turn the hydraulic hand pump fully ccw, then turn cw approximately two turns Close valve No. 2 and open valves No. 3 and Turn the hydraulic hand pump cw until an up scale indication is obtained on the gauge installed at Test Point A. If an up scale indication is obtained with only one turn of the hand pump, the system may be considered free of any air. 6

10 3.9.5 While maintaining a constant pressure on the hydraulic system with the hand pump, loosen the fitting at the gauge and purge the air from the system Continue purging the system until no more air bubbles are seen in the escaping fluid. Disconnect the gauge and cap or plug the connector block Open valve No. 2 and close valves No. 1, 3, 4, 5 and 6. Turn the hydraulic hand pump handle fully ccw, then turn cw approximately two turns Close valve No. 2 and open valves No. 3 and Ensure that the nitrogen source (item 2.3) is charged sufficiently for the pressure measurements; if not, refill as necessary. If the TI is a differential pressure indicator, ensure that the high pressure port is connected to the connector block using a pressure hose as necessary, and that the low pressure port is vented to the atmosphere Ensure that valves No. 5 and 7 are closed for TI exercising, isolating the TI from the DWT hydraulic system and null indicator. The TI should be exercised if it is used as a standard to calibrate other gauges; if not, skip to step Close valves No. 8 and 9; ensure that the pressure intensifier GAS CUT-OFF and CHARGE valves are closed and that the EXHAUST valve is open Open the nitrogen source valve slowly; ensure that the nitrogen source regulator outlet pressure gauge indication does not exceed the TI fullscale indication Exercise the TI as follows: If the TI maximum indication does not exceed the capacity of the nitrogen source, open the pressure intensifier GAS CUT-OFF valve, regulate nitrogen source pressure and open valve No. 9 to obtain a TI fullscale indication. Close valve No. 9 and open valve No. 8 slowly to vent TI pressure to zero. Close valve No. 8. Perform the charging and venting process two more times to complete the exercise If the TI maximum indication exceeds the capacity of the nitrogen source, pressure amplification is required to obtain fullscale pressure. Proceed as follows: Open the pressure intensifier GAS CUT-OFF valve, then close the EXHAUST valve Open the intensifier CHARGE valve slowly to intensify the pressure Open the valve No. 9 slowly to obtain a TI fullscale indication. Close the CHARGE valve and valve No. 9. If a fullscale indication is not reached, it will be necessary to repeat the charging process Open valve No. 8 slowly to vent TI pressure to zero, then close valve No Perform steps through two more times to complete the exercise Ensure that the TI indicates zero at the end of the exercise with valve No. 8 open and valve No. 9 closed; if not at zero, adjust the TI ZERO control as required Ensure valves No. 1, 3, 5, 6 and 7 are open. Turn the hydraulic hand pump handle as necessary to obtain a zero indication on the reference manometer. 7

11 3.17 Set the DWT null indicator to the maximum sensitivity that will provide good response without erratic movement of the meter pointer, using the SENS control or equivalent. Adjust the meter pointer for a zero indication, using the ZERO ADJ knob or equivalent. Close valves No. 6, 7, and 8. Skip to If item 2.2 is selected as the DWT to calibrate a TI up to 600 psig or 200 psid, connect the equipment as shown in Figure 2. If provided, the DWT bell jar is not required for the calibration. 2.6 PRESSURE HOSE 2.9 PRESSURE REGULATOR PRESSURE SUPPLY PORT OUTLET MANIFOLD PORT TI (SIDE VIEW) 2.6 PRESSURE HOSE or PISTON-CYLINDER ASSEMBLY 2.3 NITROGEN SOURCE CONTROL PACK Figure 2. Pressure Indication Test Setup No Ensure that steps 3.4 through 3.6 and step 3.10 have been performed Ensure that the DWT (item 2.2) is connected to an appropriate power source with the rocker switch set to off (middle position) Adjust the DWT level dial to indicate a level condition, using the two leveling screws, as necessary. If the TI is a differential pressure indicator, ensure that the high pressure port is connected to the pressure line and that the low pressure port is vented to the atmosphere Exercise the TI as follows: Load the dead weight tester with a piston, cylinder and weights which generate a pressure exceeding the fullscale indication of the TI by 10% to 20% Open the nitrogen source valve slowly; ensure that the nitrogen source regulator output pressure gauge indication exceeds the TI fullscale indication by approximately 5% Slowly adjust the control pack to obtain a fullscale indication on the TI Adjust the control pack to reduce system pressure to zero Perform steps and two more times to complete the exercise. Remove the load on the DWT Ensure that the TI indicates zero at the end of the exercise; if not at zero, adjust the TI ZERO control, as required. Skip to

12 3.24 If item 2.4 is selected to calibrate a TI of the series 710A, connect the equipment as shown in Figure PRESSURE REGULATOR PRESSURE PRESSURE HOSE HOSE TI (SIDE VIEW) LIQUID TRAP 2.3 NITROGEN SOURCE SUPPLY PORT DISCHARGE PORT SUPPLY PORT TEST PORT APC INTENSIFIER APC CONTROL UNIT TEST PORT 2.4 PPS TEST PORT Figure 3. Pressure Indication Test Setup No. 3 S The automatic pressure calibrator (APC) intensifier is utilized in this procedure. However, it is not required if the TI range is 2,000 psig or less. The precision pressure standard (item 2.4) will be referred to as the PPS in this procedure. Either PPS TEST port can be connected to the TI or to the APC control unit TEST port. If the TI is a differential pressure indicator, ensure that the indicator high pressure port is connected to the PPS TEST port and that the low pressure port is vented to the atmosphere Allow sufficient time for the PPS and APC control unit stabilization at the ambient temperature. A minimum of one hour is recommended for the PPS and for the APC before proceeding with TI exercise and TI calibration When the APC intensifier unit is used, recharge the nitrogen source when the pressure is down to approximately 500 psi. Lower pressure can be used, but the time used to boost the pressure may be excessive. Set the intensifier PRESSURE set control no higher than necessary for the desired pressure. Otherwise, pressure may be applied to a TI or sensor at a high enough rate to make control difficult and possibly cause automatic aborts. Setting the control too high may also exhaust the nitrogen supply more rapidly Ensure that the APC control unit EMERGENCY VENT valve is closed (knob up). 9

13 3.28 Set the APC intensifier controls as follows: VENT valve PRESSURE valve PRESSURE ADJUST switch POWER switch FILL VENT plug closed closed initial setting off loosen two turns for venting To conserve the gas supply, an initial setting equal to the maximum TI indication, or a setting exceeding the maximum by the least amount, is recommended Ensure that the nitrogen pressure regulator valve is closed. Open the nitrogen source supply valve slowly, and ensure that the pressure regulator does not leak. Open the pressure regulator valve to obtain the desired pressure. Ensure that the supply hose connections are free from leakage If the intensifier is used, open the intensifier PRESSURE valve and press the OIL LEVEL CHECK switch, check the oil level in the hydraulic reservoir, using the dipstick attached to the FILL-VENT plug. If the oil level is below the lower mark, add MIL-H-5606 hydraulic fluid to bring the oil level to the upper mark. Leave the FILL-VENT plug loosened by about two turns for venting. CAUTION FAILURE TO OPEN THE FILL VENT PLUG PRIOR TO OPERATION COULD RESULT IN INTERNAL OIL LEAKAGE DUE TO EXCESSIVE PRESSURE BUILDUP ON THE HYDRAULIC RESERVOIR. ALSO, FAILURE TO CLOSE THE FILL VENT PLUG PRIOR TO APC TRANSIT COULD RESULT IN OIL LEAKAGE Depress the intensifier POWER switch; open the intensifier PRESSURE valve slowly (if not already open) and ensure that the jumper hose connections are free from leakage Press the PPS control unit POWER switch to on. Ensure that the PPS display indicates that the SELF TEST process has been satisfactorily completed before proceeding. If an error message appears, turn the POWER switch to off, then on to repeat the electronics self test. If the error message repeats, interpret the error message and take the indicated corrective action Respond to the PPS display messages as follows: MESSAGE RESPONSE 1 = LOCAL CONTROL 2 = COMPUTER CONTROL Key in 1. PRINTER DESIRED: 1 = YES 2 = NO Key in 1. Press ENTER. ENTER DATE - MONTH/DAY/YEAR Key in date. Press ENTER. ENTER 3689-A S/N Key in TI serial number. Press ENTER PRESS VENT KNOB Press VENT control. PULL UP VENT KNOB Lift VENT control. XX.XXX IN HG ABS..XXX PSIG Press ADV as necessary until PPS displays TI units. 10

14 3.34 Press the APC control unit POWER switch to on When the APC display indicates that the SELF TEST process has been satisfactorily completed, allow one hour for APC to warm-up before proceeding. If any other message is displayed, turn the power off, then on to repeat the electronics self test. If the error message repeats, submit the control unit for repair and recalibration Touch ADV on the APC keyboard; respond to the APC display messages, exercising the TI, as follows: MESSAGE RESPONSE ELECTRONICS OK. PUSH ADV/CLR Press ADV. INSTALL LIQUID TRAP AT TEST PORT ADV - Press ADV. PRINTER DESIRED? 1 = YES, 2 = NO Key in 2. 1 = GAUGE OR TRANSDUCER, 2 = SWITCH Key in 1. 1 = PRESS, 2 = VAC, 3 = ABS, 4 = COMP Key in 1. 1 = GAS, 2 = LIQUID Key in 1. CONNECT GAUGE. PUSH ADV. Press ADV (already connected). ENTER FULL SCALE VALUE: Key in TI fullscale value, then press ENTER. UNITS PSI YES = ADV, NO = CLR Press CLR until TI units appear, then press ADV. ENTER TOLERANCE %: Key in 1, then press ENTER to advance program. ACCURACY 1 = FULLSCALE, 2 = IND VALUE TEST POINTS 1 = AUTOMATIC, 2 = MANUAL ENTRY Key in 2. TEST POINT ORDER IS LOW TO HIGH PUSH ADV Press ADV. ENTER TEST POINT (EXIT=ADV) Key in the TI calibrations points. Press ENTER each time then press ADV. DOWNSCALE TEST DESIRED: 1 = YES, 2 = NO Key in 1. 1 = NORMAL SCALE, 2 = RESTRICTED-CAL LAB ONLY Key in 1. CLEANING REQUIRED? 1 = YES, 2 = NO Key in 2. GAUGE EXERCISE 1 = YES, 2 = NO Key in 1. NUMBER OF CYCLES Key in 3, then press ENTER. *****SYSTEM VENTING***** No Action. AUTO EXERCISE PUSH ADV Press ADV. EXERCISING XXX PSI ACTUAL: XX.XX No Action. Allow control unit to perform the exercise routine. EXERCISING XXX PSI ACTUAL: XX.XX No Action. EXERCISING XXX PSI ACTUAL: XX.XX No Action. *****SYSTEM VENTING***** No Action. FIRST POINT XX.XX PSI PUSH ADV Press ADV to proceed with calibration. APPROACHING XX.XX PSI ACTUAL: XX.XX No Action. MANUAL SET XX.XX PSI ACTUAL: XX.XX No Action. CAUTION OBSERVE THE TI INDICATION WHILE THE APC APPLIES THE PRESSURE. IF THE PRESSURE INCREASES TOO RAPIDLY OR EXCEEDS THE TI FULLSCALE INDICATION, PRESS ABORT IMMEDIATELY TO AVOID DAMAGING THE TI. RECHECK THE FULLSCALE PRESSURE AND PRESSURE UNIT ENTERED PREVIOUSLY. 11

15 3.37 Ensure that the TI indicates zero at the end of the exercise; if not at zero, adjust the TI ZERO control, as required. Skip to 4.3. SECTION 4 CALIBRATION PROCESS S Unless otherwise specified, verify the results of each test and take corrective action whenever the test requirement is not met, before proceeding. Allow the TI and system sufficient time to reach the ambient laboratory temperature before starting the calibration. 4.1 PRESSURE INDICATION TESTS USING THE HYDRAULIC DWT - ITEM 2.1 Valves No. 4, 8 and 9 are more sensitive than the other valves. Care must be taken when closing valves No. 4, 8, and 9 to protect the stem cone from seizure with the seat Ensure the TI and equipment have been set up as shown in Figure Ensure that the TI has been exercised per step 3.14 and that steps 3.15 through 3.17 have been performed. Re-adjust the DWT meter pointer for a zero indication, using the ZERO ADJ knob or equivalent, as necessary. Do not adjust the ZERO ADJ knob or equipment for the remainder of the calibration test Place the weight adapter and weights corresponding to the first TI calibration point on the DWT turntable Raise the DWT piston and weights to maximum height, using the hydraulic hand pump handle. Set the DWT rotation switch to cw and start the weights spinning by hand, as required Turn the hydraulic hand pump handle cw until the standard piston is floating at its reference position. The standard piston is floating at its reference position when the index lines on the two vertical pins at the bottom of the weight holder are aligned with the index line on the housing; or, at higher weight loadings with the large bottom sleeve weight installed, when the index line on the outer rim of the sleeve weight is aligned with the index line on the large swivel pin Open valve No. 7; ensure that valve No. 8 is closed Generate pneumatic pressure to balance the hydraulic pressure by operating the nitrogen source regulator and DWT pressure intensifier controls, and valves No. 8 and 9, as described in step 3.14, except a fullscale indication is not required. CAUTION EXERCISE CARE NOT TO APPLY PNEUMATIC PRESSURE EXCEEDING THE HYDRAULIC PRESSURE; OBSERVE THE PNEUMATIC HAND PUMP GAUGE AND DWT NULL INDICATOR CONTINUALLY. EXCESSIVE PNEUMATIC PRESSURE WILL CAUSE ERRATIC DWT METER RESPONSE AND POSSIBLY DAMAGE THE DIFFERENTIAL PRESSURE CELL DIAPHRAGM. 12

16 4.1.8 Turn the hydraulic and pneumatic hand pump handles, as required, until the standard piston is floating at its reference position and the DWT null indicator is at center scale, indicating a state of equilibrium. If the pneumatic hand pump piston reaches the end-stop before equilibrium can be achieved, close valve No. 7, back off the piston with the hand pump handle, increase the pneumatic pressure slightly, reopen valve No. 7 slowly, and proceed with the pressure balancing process Verify that the TI indication, compared to the true pressure calculated in step 3.5, is within the TI tolerance limits listed Perform steps through for each remaining increasing pressure calibration point Close valve No. 9 and slowly open valve No. 8 to vent the pneumatic pressure to obtain approximately the first decreasing pressure calibration point. Close valve No Raise the piston to the top of its stroke with the hydraulic hand pump handle. Remove the appropriate weights to obtain the first decreasing pressure calibration point Turn the hydraulic and pneumatic hand pump handles, as required to maintain a slightly greater hydraulic pressure, until the standard piston is floating at its reference position and the DWT null indicator is at center scale, indicating a state of equilibrium. The gas pressure must not be allowed to exceed that of the oil by an amount sufficient to over range the DWT diaphragm inversely. If over-ranging occurs, raise the oil pressure against the piston stop by one or two hundred psi to reset the diaphragm before proceeding Verify that the TI indication, compared to the true pressure calculated in step 3.5, is within the TI tolerance limits listed Perform steps through for each remaining decreasing pressure calibration point Close the nitrogen source valve and open valve No. 8 to reduce the pneumatic system pressure to zero Remove the remaining DWT weights and turn the hydraulic hand pump handle, as required to obtain a null indicator center scale indication at zero pressure Unless other measurements are to be performed, close valves No. 1, 3, 4, 7, 8, 9, and disconnect the TI, cap or plug the block connector, and secure the equipment Affix a black-on-white CALIBRATED label to the TI. 4.2 PRESSURE INDICATION TESTS USING THE PNEUMATIC DWT - ITEM 2.2 The item 2.2 DWT may be utilized up to 600 psi only Ensure that steps 3.20 and 3.21 have been performed, that the TI has been exercised per step 3.22 and zeroed per step Load the DWT with a piston, cylinder and weights corresponding to the first TI calibration point on the checklist. Ensure that the control pack valves are closed. 13

17 4.2.3 Open the nitrogen source valve; ensure that the nitrogen source regulator output pressure indication exceeds the TI fullscale indication by 5 to 10% Use the control pack valves to increase pressure slowly. When the TI indicates approximately 0.1 to 0.3 psi below the calibration point, close the valves Slowly turn the control pack hand wheel cw until the DWT piston, cylinder and weights lift and begin to float. Spin the weights, as required Verify that the TI indication, compared to the true pressure calculated in step 3.5, is within the TI tolerance limits listed. Open the controller shut off valve Perform steps and through for each remaining increasing pressure calibration point Use the control pack valves to decrease pressure slowly. When the TI indicates approximately 0.1 to 0.3 psi above the first decreasing pressure calibration point, close the valve Remove the appropriate weights from the DWT to obtain the first decreasing pressure calibration point; turn the controller hand wheel to or near its extreme cw position and close the controller shut off valve Slowly turn the control pack wheel ccw until the DWT piston, cylinder and weights lower and begin to float. Spin the weights, as required Verify that the TI indication, compared to the true pressure calculated in step 3.5, is within the TI tolerance limits listed. Open the controller shut off valve Perform steps through for each remaining decreasing pressure calibration point Ensure Control Valve #1 is closed; slowly open Control Valve #2 to reduce system pressure to zero. Remove the remaining load on the DWT Unless other measurements are to be performed, close the nitrogen source valve, open Control Valve #1, disconnect and secure the equipment Affix a black-on-white CALIBRATED label to the TI. 4.3 PRESSURE INDICATION TESTS USING THE PPS Do not use this section to calibrate a TI with an accuracy better than ±0.1% of the range span Ensure that steps 3.25 through 3.37 have been performed and that the TI has been exercised per step Use the INCREASE/DECREASE control to obtain a stable indication on the TI equal to the first calibration point, as indicated in the checklist. The final indication for each upscale test point must be approached in the direction of increasing pressure, and the final indication for each downscale test point must be approached in the direction of decreasing pressure Ensure that the APC pressure intensifier (as applicable) PRESSURE set control is set equal to or the next step above the calibration point pressure Press MEAS on both the APC and PPS control unit keypad. Verify that the result obtained is within the TI tolerance limits on the checklist. The calibration record printed by the PPS may be used to transcribe the measured values to the applicable checklist. Indicate any out-of-tolerance points, and fill in all required data. 14

18 4.3.5 Ensure that the PPS printer correctly prints the test data, including the TI calibration point, true pressure as measured by the PPS, and the deviation of the TI from the true pressure If an error is evident, depress BACK STEP and repeat the step. The APC display pressure value is advisory only Perform steps through at each remaining pressure calibration point on the checklist Depress ABORT on the APC panel to reduce system pressure to zero Unless other measurements are to be performed, proceed to Section APC/PPS SYSTEM SHUT DOWN Set the APC control unit, APC pressure intensifier and PPS control unit POWER switch to off Close the nitrogen source supply valve. Close the nitrogen source regulator valve. Press VENT on PPS Open, then close the APC intensifier VENT valve. The APC may be left in this condition for short periods of nonuse or at a semi-permanent location. Before moving the APC and PPS, complete the following steps Tighten the pressure intensifier FILL-VENT plug Disconnect the liquid traps from the PPS Disconnect all hoses, attach dust covers, wipe clean, and stow in the accessory case Attach dust covers to all APC and PPS ports Disconnect and stow electrical cords Attach case covers Affix a black-on-white CALIBRATED label to the TI. (16 blank) 15

19 CALIBRATION CHECKLIST TEST INST(S) Heise 710A Digital Pressure Indicator, 0 to 100 psig PROC. NO. NA 17-20MP-155 MFR MODEL SER. NO. PROCEDURE MEASURED VALUES OUT STEP FUNCTION TESTED NOMINAL FIRST RUN SECOND RUN OF CALIBRATION TOLERANCES NO TOL (1) (2) (3) (4) (5) (6) (7) 3.1 TI inspection -- ck ( ) NA 3.22 TI exercise -- ck ( ) NA 3.23 TI zero -- ck ( ) NA 4.2 Pressure Indication Tests Using the Pneumatic DWT-item 2.2 Increasing pressure (psig) (psig) TI indication 10 ±0.10 of true pressure Decreasing pressure (psig) (psig) TI indication 90 ±0.10 of true pressure Page 1 of 1 (18 blank) 17

20 CALIBRATION CHECKLIST TEST INST(S) Heise 710A Digital Pressure Indicator, 0 to 1000 psig PROC. NO. NA 17-20MP-155 MFR MODEL SER. NO. PROCEDURE MEASURED VALUES OUT STEP FUNCTION TESTED NOMINAL FIRST RUN SECOND RUN OF CALIBRATION TOLERANCES NO TOL (1) (2) (3) (4) (5) (6) (7) 3.1 TI inspection -- ck ( ) NA 3.9 DWT system purged -- ck ( ) NA 3.14 TI exercise -- ck ( ) NA 3.15 TI zero -- ck ( ) NA 4.1 Pressure Indication Tests Using the Hydraulic DWT-item DWT meter zero -- ck ( ) NA Increasing pressure (psig) (psig) TI indication 100 ±1.0 of true pressure Decreasing pressure (psig) (psig) TI indication 900 ±1.0 of true pressure Page 1 of 1 (20 blank) 19

21 CALIBRATION CHECKLIST TEST INST(S) Heise 710A Digital Pressure Indicator, 0 to psig PROC. NO. NA 17-20MP-155 MFR MODEL SER. NO. PROCEDURE MEASURED VALUES OUT STEP FUNCTION TESTED NOMINAL FIRST RUN SECOND RUN OF CALIBRATION TOLERANCES NO TOL (1) (2) (3) (4) (5) (6) (7) 3.1 TI inspection -- ck ( ) NA 3.32 PPS self test -- ck ( ) NA 3.35 APC self test -- ck ( ) NA 3.36 TI exercise -- ck ( ) NA 3.37 TI zero -- ck ( ) NA 4.3 Pressure Indication Tests Using the PPS Increasing pressure (psig) (psig) TI indication 1,000 ±10 of true pressure ,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 Decreasing pressure (psig) (psig) TI indication 9,000 ±10 of true pressure 8,000 7,000 6,000 5,000 4,000 3,000 2,000 1,000 Page 1 of 1 (22 blank) 21

22 CALIBRATION CHECKLIST TEST INST(S) Heise 710B Digital Pressure Indicator, 0 to 50 in Hg PROC. NO. NA 17-20MP-155 MFR MODEL SER. NO. PROCEDURE MEASURED VALUES OUT STEP FUNCTION TESTED NOMINAL FIRST RUN SECOND RUN OF CALIBRATION TOLERANCES NO TOL (1) (2) (3) (4) (5) (6) (7) 3.1 TI inspection -- ck ( ) NA 3.22 TI exercise -- ck ( ) NA 3.23 TI zero -- ck ( ) NA 4.2 Pressure Indication Tests Using the Pneumatic DWT-item 2.2 Increasing pressure (in Hg) (in Hg) TI indication 5 ± of true pressure Decreasing pressure (in Hg) (in Hg) TI indication 45 ±0.025 of true pressure Page 1 of 1 (24 blank) 23

23 CALIBRATION CHECKLIST TEST INST(S) Heise 901B Digital Pressure Indicator, 0 to 30 psig PROC. NO. NA 17-20MP-155 MFR MODEL SER. NO. PROCEDURE MEASURED VALUES OUT STEP FUNCTION TESTED NOMINAL FIRST RUN SECOND RUN OF CALIBRATION TOLERANCES NO TOL (1) (2) (3) (4) (5) (6) (7) 3.1 TI inspection -- ck ( ) NA 3.22 TI exercise -- ck ( ) NA 3.23 TI zero -- ck ( ) NA 4.2 Pressure Indication Tests Using the Pneumatic DWT-item 2.2 Increasing pressure (psig) (psig) TI indication 3 ±0.011 of true pressure Decreasing pressure (psig) (psig) TI indication 27 ±0.011 of true pressure Page 1 of 1 (26 blank) 25

24 CALIBRATION CHECKLIST TEST INST(S) Heise 901B Digital Pressure Indicator, 0 to 5000 psig PROC. NO. NA 17-20MP-155 MFR MODEL SER. NO. PROCEDURE MEASURED VALUES OUT STEP FUNCTION TESTED NOMINAL FIRST RUN SECOND RUN OF CALIBRATION TOLERANCES NO TOL (1) (2) (3) (4) (5) (6) (7) 3.1 TI inspection -- ck ( ) NA 3.9 DWT system purged -- ck ( ) NA 3.14 TI exercise -- ck ( ) NA 3.15 TI zero -- ck ( ) NA 4.1 Pressure Indication Tests Using the Hydraulic DWT-item DWT meter zero -- ck ( ) NA Increasing pressure (psig) (psig) TI indication 500 ±1.8 of true pressure ,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000 Decreasing pressure (psig) (psig) TI indication 4,500 ±1.8 of true pressure ,000 3,500 3,000 2,500 2,000 1,500 1, Page 1 of 1 (28 blank) 27

25 CALIBRATION CHECKLIST TEST INST (S) Druck DPI601 Digital Pressure Indicator PROC. NO. NA 17-20MP-155 MFR MODEL SER. NO. PROCEDURE MEASURED VALUES OUT STEP FUNCTION TESTED NOMINAL FIRST RUN SECOND RUN OF CALIBRATION TOLERANCES NO. TOL (1) (2) (3) (4) (5) (6) (7) 3.1 TI inspection -- ck ( ) NA 3.22 TI exercise -- ck ( ) NA 3.23 TI zero -- ck ( ) NA 4.2 Pressure Indication Tests Using the Pneumatic DWT-item 2.2 Increasing pressure (psig) (psig) TI indication 3 ±0.015 of true pressure Decreasing pressure (psig) (psig) TI indication 27 ±0.015 of true pressure Page 1 of 1 29

26 APPENDIX A REPRESENTATIVE TEST INSTRUMENTS TIs that can be calibrated by this procedure include, but are not limited to, the following: Model Manufacturer Tolerance Nomenclature Mensor Corp ±0.025% fs Digital Pressure Gauge 66B2A0300 Wallace and Tiernan ±0.05% fs Digital Pressure Gauge 66B2C0140 Wallace and Tiernan ±0.05% fs Digital Pressure Gauge 710A Heise Instrument Div ±0.1% fs Digital Pressure Indicator 710B Dresser Industries ±0.05% fs Digital Pressure Indicator 835C Dresser Industries ±0.035% fs Digital Pressure Indicator 901A Dresser Industries ±0.07% fs Digital Pressure Indicator 901B Dresser Industries ±0.035% fs Digital Pressure Indicator DPI601* Druck ±0.05% fs Digital Pressure Indicator PCL3000D Omega Engineering ±0.05% of range Pressure Standard *The full-scale pressure of the TI can be determined by review of the front panel display and keypad. A-1

27 APPENDIX B PRESSURE UNIT CONVERSION FACTORS These conversion factors are in accordance with SECNAVINST OP-401E of June 1978, ASTM E380 (Amer Nat Std Z210.1) of January 1976 and NBS Monograph 8, National Bureau of Standards, May Select the conversion factor that will provide a comparison of measurements relative to a common temperature; e.g., if the standard and the TI provide measurements in inches of water and the standard references 4 C while the TI references 20 C, multiply the TI values by lb/in 2 in of H 2 O (20 C) in of Hg (0 C) in of H 2 O (4 C) mm of Hg(0 C) Pascal lb/in 2 = x 10 3 in of H 2 O = (20 C) in of Hg = (0 C) in of H 2 O = (4 C) mm of Hg (0 C) 1 Atmosphere = x 10-2 x 10-2 x x x 10-2 x 10-2 x x 10-2 x 10-2 x x 10 5 Pascal = x x x x x B-1