1. Understanding Xinyulin's Pressure Testing Units
Shenyang Xinyulin Petroleum Machinery Co., Ltd., located in the Shenbei New District of Shenyang, is a recognized high-tech enterprise in Liaoning Province. The product line for pressure testing is comprehensive, including electric, pneumatic, and vehicle-mounted units, specifically designed for testing well control equipment in oil drilling and production. The company possesses solid technical capabilities, holding 38 patents. Notably, we filed a new patent last year for an electric pressure test pump featuring an improved connection head structure with a more durable stop ball and enhanced sealing stability.
In essence, these units perform "health checks" on well control equipment like blowout preventers (BOPs) and manifolds, verifying their sealing integrity and pressure-bearing capacity. On the oilfield site, equipment downtime can significantly impact production. Therefore, it's crucial for field personnel to diagnose and resolve common malfunctions independently.
2. Analysis of Common Faults and Their Causes
2.1 Pump Fails to Suction or Discharge Water
This is a frequent and frustrating issue. The motor runs, but pressure doesn't build, or water output is intermittent.
Potential Causes:
A. Air leakage or improper installation of the suction pipe, or a misaligned/worn seal.
B. Clogged strainer in the water tank due to silt or debris.
C. Inlet valves gummed up by scale or deposits from prolonged inactivity.
D. A damaged strainer allowing foreign objects to enter and jam the inlet/outlet valve ports.
2.2 Unsteady Pressure Rise, Gauge Needle Fluctuates
During pressurization, the gauge needle jumps erratically instead of rising smoothly.
Potential Causes:
A. Primary suspect: Leakage in the test piece or connecting pipelines.
B. Insufficient or contaminated water in the tank.
C. Clogged inlet strainer (again).
D. Air trapped in the pump's liquid cylinder.
E. Worn valve seats or foreign material obstructing the inlet/outlet valves, causing poor sealing.
F. Loose or damaged plunger packing, leading to leakage.
G. Pressure relief valve not fully closed or not sealing properly.
2.3 Failure to Hold Pressure After Shutdown
Pressure drops steadily after the pump is stopped, failing the pressure hold test.
Potential Causes:
A.Most common: Leakage in the test piece or connecting lines.
B. Worn seal or debris on the discharge (holding) valve seat.
C. Pressure relief valve not sealing tightly.
2.4 Inability to Reach Required Pressure
Sometimes, the system can't even achieve the target pressure.
Potential Causes:
A.Complete failure of inlet/outlet valves.
B.Leaking safety valve.
C.Leakage in the discharge pipeline.
D.Malfunctioning check valve.
2.5 Other Issues: Abnormal Noises and Overheating
2.5.1 Knocking sounds during operation: Possible causes include insufficient or degraded lubricating oil; excessive wear in crankshaft bushings or crosshead liners; improperly adjusted bearing caps or failed bearings.
2.5.2 Overheating plunger and high-pressure cylinder: Over-tightened packing; no medium entering the pump cylinder; part friction; or lack of lubrication on the plunger.
2.5.3 No oil pressure in crankshaft lubrication system: Motor running in reverse direction; air leak in the suction line; low oil level in the gearbox introducing air; or a faulty gear pump.
3. Troubleshooting and Debugging Solutions (Practical Guide)
For Pump Suction/Discharge Failure:
A. Inspect Suction Line: Disassemble and reassemble, ensuring tight connections and proper, undamaged seals.
B. Clean the Strainer: Remove and thoroughly flush the tank strainer. Replace if torn.
C. Bleed Air: Disconnect the pump outlet briefly and let it run to purge air until discharge is steady and bubble-free.
D. Clean Inlet Valves: For idle pumps, disassemble and clean valve components with diesel or kerosene to remove scale and deposits.
For Unsteady Pressure or Pressure Hold Issues:
A. Leak Detection is Key: Before and during pressure hold, meticulously inspect all test pieces, connections, welds, and hoses. Soapy water is effective for locating leaks.
B. Ensure Clean Water Supply: Keep the tank filled with clean water or specified test medium (5-60°C ideal). Contaminated fluid causes wear and clogging.
C. Lap or Replace Valves: For leaking valves, disassemble and lap the seats. Replace if severely worn. Xinyulin's patented rotatable stop ball design aims to reduce localized wear.
D. Adjust/Replace Packing: For plunger leaks, first try tightening the gland. If leakage persists or packing is worn, replace it. Clean the plunger surface and stuffing box thoroughly during replacement.
For Failure to Reach Pressure:
A. Check Safety & Check Valves: Test, lap, or replace faulty safety or check valves.
B. Inspect Entire Discharge Line: Check all fittings, valves, and pipes from the pump outlet to the test piece for leaks.
General Debugging & Precautions:
A. Pre-start Check: Verify crankshaft oil level (use N46 or ISO VG 46/40# machinery oil). Check all fastener tightness, electrical insulation, and grounding.
B. No-load Run: Start the pump and let it run briefly without load (ensure water is present!). Listen for unusual sounds and check for steady discharge before connecting the test piece.
C. Pressurization Technique: For large-volume test pieces, use continuous operation for initial fast pressure rise. Switch to intermittent operation (jogging) as pressure nears the target to avoid over-pressurization. Pressure gauge range should be ≥1.5 times the test pressure.
D. Safety First: Never disassemble any components under pressure! Always depressurize and disconnect power before maintenance. Keep personnel in a safe area during testing.
4. Maintenance Recommendations (Extending Equipment Life)
Proper maintenance prevents most failures.
A.Lubrication is Vital: Change oil after the first 40 hours of operation for a new pump, then after 80 hours, and approximately every 200 hours thereafter. Always keep the oil clean.
B.Maintain Cleanliness: Clean the unit's exterior regularly. Always flush the water tank before filling. Prevent contaminants from entering the system.
C.Winterization: In cold climates, completely drain all water from the pump and lines after use to prevent freezing damage.
D.Regular Inspection: Periodically check all connections for tightness and the condition of seals. Maintain a maintenance log to track recurring issues.
Conclusion
In summary, the pressure testing units from Shenyang Xinyulin Petroleum Machinery Co., Ltd. are robustly designed. Many faults stem from improper operation or lack of maintenance. By understanding these common issues, adhering to standard operating procedures, and performing diligent maintenance, field personnel can resolve most problems. For complex issues, always consult the manufacturer's technical support. Safe and efficient operations depend on reliable equipment, and maintaining these units properly is fundamental to ensuring uninterrupted oilfield production. I hope this shared practical experience proves helpful to fellow technicians in the field.