TROUBLE LOCATING OF RECIPROCATING PUMPS.

Hallo teman - teman semuanya, ketemu lagi dengan tulisan - tulisan dhevils mechanic yang tak jauh membahas dunia mechanic Oil and Gas Industry, dan kali ini dhevils inginrangkum troubleshoot pada pompa reciprocating  yang kita jabarkan problem dan dimana kita harus mengechecknya.

Low Volumetric Efficiency (Failure To Deliver Rated Capacity and Pressure)

1) Air or vapor pocket in inlet line.
2) Capacity of charge pump less than capacity of power pump
3) Air or vapor trapped in or above inlet manifold.
4) Air leak in liquid supply piping system.
5) Loose bolts in pump inlet manifold
6) Air or gases entrained in liquid.
7) Foreign object holding pump inlet or discharge valve(s) open.
8) Incorrect drive ratio
9) Loose belts
10) Incorrect motor or engine speed
11) Loose valve covers or cylinder head
12) Worn valves and seats
13) Safety relief valve partially open, or not holding pressure
14) Worn liners, piston rings or plungers
15) Bypass valve open, or not holding pressure
16) Blown liner gasket
17) NPSA not sufficient
18) Liquid bypassing internally
19) Foreign object blocking liquid passage
20) Vortex in supply tank
21) Insufficienct power delivered by motor

 

NPSHA Too Low 

1) Inlet line partially clogged

2) Liquid vapor pressure too high

3) Liquid pumping temperature too high

4) Restricted inlet pipe fittings

5) Inlet line too long

6) Too many pipe fittings

7) Too small inlet line

8) Too low static inlet head

9) Too low atmospheric pressure

Liquid Not Delivered 1) Pump not primed

2) Air or vapor pocket in inlet line

3) Clogged inlet line

4) All inlet valves propped open

5) All discharge valves propped open

6) Loose bolts in pump inlet manifold

7) Too high valve velocities

Cavitation 

1) NPSHA too low

2) Liquid NOT Delivered to Pump Inlet Connection

3) Excexxive Stuffing Box Leakage

4) NPSHR too high

Leak at Cylinder Head or Valve Cover 

1) Over Recommended Pressure

2) Loose Cylinder Head/Valve Cover

3) Damaged Gasket/O-ring

Water in Crankcase/Oil 

1) Water Condensation

2) Worn seals

3) Clogged Air Breather(s)

4) Worn Crankcase Packing

5) Loose Covers

Oil Leakage from Crankcase 

1) Oil Level/Temperature Too High

2) Worn seals

3) Worn Crankcase Packing

4) Loose Crankcase Cover

Excessive Heat in Power End 

1) Pump Running Backward/RPM too low

2) Insufficient Oil in Power End

3) Excessive Oil in Power End

4) Incorrect Oil Viscosity

5) Operating Pump above Recommended Pressure

6) Main Bearings too Tight

7) Drive Misaligned

8) Belts too Tight

9) Discharge Valve, one or more, Stuck Open

10) Insufficient Cooling

11) Pump RPM too Low

12) Inadequate Ventilation

13) Liquid End Packing Adjusted too Tight (adjustable style packing only)

Pump Overloads Driver 

1) Pump RPM too High

2) Low Voltage or other Electrical Trouble

3) Trouble with Engine, Turbine, Gear Reducer or other Related Equipment

4) Excessive Discharge Line Pressure

5) Clogged Discharge Line

6) Closed/Throttled Valve in Discharge Line

7) Incorrect Plunger/Piston Size for Application

8) Improper Bypass Conditions

9) Over-tightened Stuffing Box Gland on Adjustable Packing

Stuffing Box Leakage 

1) Worn Packing

2) Worn rods or plunger

3) Worn stuffing boxes

4) Wrong size packing

5) Worn O-ring seal (replaceable boxes)

Stud Failure 

1) Excessive discharge pressure

2) Improper torquing of nuts

3) Shock overload caused by pump cavitation.

Excessive Valve Noise 

1) Broken or weak valve spring

2) Pump cavitation

3) Air leak in inlet piping or loose bolts in pump inlet manifold

4) Air trapped above inlet valve

Inlet or Discharge Line Vibration 

1) Piping inadequately supported

2) Inlet line too long or too small in diameter

3) Too many bends in inlet line

4) Multiple pump installations operating in phase

5) Obstruction Under Valve(s)

6) Packing Worn

7) Operating Above Recommended Pressure or RPM

8) Low NPSHA

Noisy Operation (Be sure to differentiate between liquid knock and mechanical knock-very few knock are mechanical on new installations.) 

1) Piston por Plunger loose

2) Valve moise amplified through power end

3) Pump cavitation

4) Liquid knock

5) Air leak in inlet piping

6) Loose bolts in pump inlet manifold

7) Hydraulic noise in liquid end

8) Loose or worn crosshead pins and bushings

9) Loose connecting rod cap bolt

10) Worn connecting rod bearings

11) Worn crosshead

12) Min bearing end play excessive

13) Worn gears or chains

14) Gears or chains out of lone

15) Pump running backward

16) Partial loss of prime

17) Shocks in piping system

18) Water in power end crankcase

19) Poorly supported piping, abrupt turns in piping, misaligned, pipe size too small.

Broken Shafts, Bent, Stripped Threads And Other Catastrophic Failures 

1) Start-up against closed gate valve in discharge line. Ef valve seats are discovered driver too deeply after operation of the pump, look for the following pattern of driven seats, indicative of start-up or run against of closed discharge line valve:

Triplex single acting plunger pump: 2 inlet and 1 discharge valve seat, or 1 inlet and 2 discharge valve seats.

Quintuplex single acting plunger pump: 3 inlets and 2 discharge valve seats, or 2 inlets and 3 discharge valve seats.

Duplex double acting piston pumps: 2 inlets and 2 discgarge valve seats.

2) Low Oil level

3) Contaminated oil

4) Main bearing failure

5) Piston or plunger striking cylinder head.

6) Disintegration of worn valves

7) Frozen liquid in liquid body

8) Air leak in liquid supply system

9) Loose bolts in pump inlet manifold

Packing Failure 1) Normal wear

2) Improper material

3) Improper lubrication

4) Adjustable packing – gland tightened excessively

5) Dirty liquid

6) Plunger or piaton rod mosal;ignment

7) Dirty environment

Valve Failure 

1) Normal wear

2) Pump cavitation

3) Abrasives in fluid

4) Incompatibility of valve components to corrosive liquid

5) Electrolysis

6) Incorrect installation – driving on the valve stem, improper torque on jam nut, valve seat and valve deck not thoroughly clean and dry when seat installed.

Plunger Failure 

1) Thermal shock ( cold water hitting hot ceramic plunger)

2) Packing too tight

3) Inlet valve dislocated/disassembled during pump operation.

4) Stuffing box gland rubbing on plunger due to improper tightening procedure.

5) Dirty liquid

6) Dirty environment.

Demikianlah beberapa problem yang terjadi di pompa reciprocating dan penyebabnya, sehingga kita sebagai mechanic akan lebih mudah menyeleseikan permasalahan dilapangan