Scope: This guideline identifies the methods to be used for troubleshooting proving operations using pipe provers.
PIPE PROVER TROUBLESHOOTING FOR OPERATIONS
Frequency: As indicated below
Procedure
| Problem | Location & Probable Cause | Test/Inspection | Corrective Action |
| Poor Repeatability | —– Pipe Prover —– | ||
| Entrapped air or vapor | Open vent with sphere traveling, check for air or vapor. (This may not give positive response because of possible air or gas pockets.) |
a) Check for air in fluid to prover, vent all high points, and run prover several times and vent. b) Increase meter back-pressure.
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| Flashing in the 4-way diverter valve or sphere-handling valve. |
Measure pressure at the valve at maximum flow rate and see if it is in accordance with specification. |
Increase pressure by using back-pressure valve. |
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| Isolating valve leakage | Check double block-and bleed for leakage. | a) Seal valve more firmly by increasing actuator or hand wheel torque.
b) Repair valve. c) Cycle valve to remove debris.
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| Cycle time of the 4way diverter valve or sphere-handling valve |
Check double block-andbleed closure before sphere detector. |
Increase speed of operation of the valve or decrease flow rate through the prover. |
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| Accessory gear wear | Analyze pulse train with oscilloscope. |
Repair and clean as necessary.
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| Turbine meter straightening section |
Remove and inspect for damage. |
Repair or replace as required. |
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Random electrical interference |
a) Identify sources
b) Analyze pulse train with |
a) reroute cable
b) Use shielded cable. c) Check cable ground |
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| Cavitation in meter | a) Draw sample and observe for stability at atmospheric pressure. b) If unstable, measure c) Measure pressure d) Evaluate back-pressure. |
Increase back-pressure. | |
| Pulse generator faulty | a) At constant flow rate check that pulse frequency is constant. b) Pulse integrity check. c) Analyze pulse train with |
Repair or replace as required. |
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| Damaged PD or turbine meter rotor |
a) Dismantle and inspect.
b) Analyze pulse train with |
Repair or replace as required. |
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| Drag or wear of gears, couplers, etc. |
Head check or successive runs. |
Re-align or replace as required. |
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| Miscellaneous problems encountered when proving. | |||
| Faulty calibrator | a) Analyze pulse train with oscilloscope. b) Adjust up and down and |
Repair or replace as required. |
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| Pressure variation | Check gauges. | a) Look for cavitation.
b) Check back-pressure |
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| Temperature variation. | Check temperature sensors. | Maintain stable flow condition. |
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| Poor linearity | —– Pipe Prover —– | ||
| Cycle time of the 4way diverter valve or sphere-handling |
a) Evaluate meter factor changes. b) Check double block-andbleed |
Repair or replace as required. b) Increase speed of
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| Temperature variation | Verify temperature measurements. |
Stabilize temperature at meter and prover. |
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| —– Field Meter —– | |||
| Meter bearing wear | a) Dismantle and inspect.
b) Analyze pulse train with |
Repair or replace as required. |
|
| Damaged PD or turbine meter rotor |
a) Dismantle and inspect.
b) Analyze pulse train with |
Repair or replace as required. |
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| Decrease in meter registration, meter factor increases |
Prover temperature too low. |
Stabilize temperature. | |
| Meter | Replace bearings or replace meter. |
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| Increase in meter registration, meter factor decreases |
Prover temperature too high. |
Check thermometer. | |
| Fluid viscosity increase |
Stabilize viscosity. | ||
| Decrease in meter registration, meter factor decreases |
Build-up on prover pipe wall. |
Clean prover. | |
| Increase or decrease in meter registration, meter factor increases or decreases |
Meter calibrator. | Lubricate or replace calibrator. |
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| Severe change in meter factor |
Malfunction in ATC assembly. |
Perform hot and cold test. |
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| Severe decrease in meter factor |
Collapsed bulb and bellows. |
Replace bulb and bellows. |
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| Displacer undersized. | Resize or replace displacer |
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| Sever increase in meter factor |
a) Malfunction of calibrator |
Repair or replace as required. |
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| b) Inner mechanical problem | Repair or replace as required. |