Centrifugal pump is used for transferring drilling mud. It can be used as feeding pump for desander, desilter or used as mixing pump for jet mud mixer. Also it can be used as trip pump, and supercharging pump for rig mud pump.

Centrifugal Pump

But how to do if centrifugal pump breaks down in the process of mud solids control? Now we introduce some processing methods for centrifugal pump breakdown resulting from various reasons.

1. pump can not start or load too big

(1) prime mover or power is not normal. The processing method is check the power and prime mover.

(2) pump stuck. The processing method is using hand shaft coupling to check, if necessary, eliminate static and dynamic parts faults.

(3) packing gland too tight. The processing method is relaxing packing.

(4) discharge valve has not been closed. The processing method is closing discharge valve, restart.

(5) balance pipe is not unobstructed. The processing method is dredge balance pipe.

2. pump not drainage

(1) insufficient irrigation pump (or inner pump gas is not throughly exhausted). The processing method is to infuse pump.

(2) Wrong pump rotating direction. Method is to check rotating direction.

(3) Pump rotating speed is too slow. Method is check rotate speed, faster it.

(4) mesh plugging, bottom valve is ineffective. The processing method is check mesh, eliminate sundry.

(5) smoke height is too high, or suction liquid tank occurs vacuum. The processing method is to reduce suction height, Check absorb liquid tank pressure.

3. pump breaks after drainage

(1) inhaled pipeline leaks. The processing method is to check inhaled side pipe joints and packing box sealing.

(2) When filling pump, suction side gas is not over. The processing method is asked to infuse pump.

(3) inhaled side was suddenly blocked by foreign bodies. The processing method is stop the pump to handle foreign bodies.

(4) inhale amount of gas. The processing method is checking the suction whether has vortex, submerged depth whether is too shallow.

4 . insufficient flow

(1) Same with 2(1), 3(1). The processing method is adopt corresponding measures.

(2) system static head increases. The processing method is to check liquid height and the system pressure.

(3) resistance losses increases. The processing method is to check piping and check valve obstacles.

(4) shell and impeller wear-resisting rim wear is too big. The processing method is change or repair wear-resisting ring and impeller.

(5) other part leakage. The processing method is check shaft sealing etc parts.

(6) pump impeller jams, wear and corrosion. The processing method is clean, check, replace .

5. insufficient head

(1) Same with the 2 (1), (2), (3), (4) and 3(1), 4 (6). The processing method is adopt corresponding measures.

(2) impeller reverse installation (double suction wheel). The processing method is check impeller.

(3) liquid density and viscosity is not conform to design conditions. The processing method is check liquid physical properties.

(4) when operating flow is too big. The processing method is reducing flow.

6. large power consumption in operation

(1) impeller and wear-resisting ring, impeller and shell has friction. The processing method is check and repair.

(2) Same with 5(4). The processing method is reduce flow.

(3) liquid density increases. The processing method is check liquid density.

(4)packing gland is too tight or dry friction. The processing method is relax packing, check water pipe.

(5) Bearing is damage. Method is check, repair or replace bearing.

(6) Ratate speed is too fast. Method is to check driver and power.

(7) Bend pump shaft. Method is correct shaft.

(8) axial force balance device failure. The processing method is check balance hole, return pipe whether is blocked.

(9) couplings centring is bad or axial gap is too small. The processing method is checking centring circumstance and adjust axial clearance.

7. pump vibration or abnormal noise

(1) Same with 3 (4), 6(5), (8), (9). The processing method is adopt corresponding measures.

(2) vibration frequency is 0 ~ 40% of working rotate speed. Excessive bearing clearance, axle bush loose, oil has impurities, oily (viscosity and temperature) bad, because air or process liquid make oil foam, bad lubrication, bearing damage. The processing method is examine, adopt corresponding measures, such as adjusting bearing clearance to remove oil impurities, replace new oil.

(3) vibration frequency is 60% ~ 100% working speed. Relevant bearing problem same with (2), or is sealed large clearance, protect circle become loose, sealing wear. The processing method is checking, adjustment or replace the seal.

(4) vibration frequency is 2 times working speed. No centring, couplings loose, sealing device friction, shell deformation, bearing damage, supporting resonance, thrust bearing damage, shaft bending, poor coordination. The processing method is check, adopt corresponding measures, repair, adjust or change.

(5) vibration frequency is n times of working speed. Pressure pulsation, no centering, shell deformation, sealed friction, supporting or fundamental resonance, pipe, machine is resonant, processing method is same with (4), strengthening basic or piping.

(6) vibration frequency is very high. Axis friction, seal and bearing, inaccurate, bearing jitter, bad contraction cooperate, etc. Treatment is same with (4).

8. bearing heating

(1) bearing pad scrape grind don't meet requirement. The processing method is to repair bearing pad or replacement.

(2) bearing clearance is too small. The processing method is readjust bearing clearance or blow grind.

(3) lubricant volume is insufficient, oily adverse. The processing method is increasing oil or replace lubricating oil.

(4) bearing assembly is bad. The processing method is check according to requirement, eliminate not meet requirement factors.

(5) cooling water open circuit. The processing method is check, repair.

(6) bearing wear or loose. The processing method is repair bearings or scrap. If loose, tighten relevant bolt.

(7) pump shaft bending. The processing method is correctional pump shaft.

(8) Swinging oil ring deformation, swinging oil ring cannot turn, without oily. The processing method is update jilt oil ring.

(9) Couplings centring is bad or axial gap is too small. The processing method is check centring circumstance and adjust axial clearance.

9. shaft sealing heating

(1) packing gland too tight or friction. The processing method is relax packing, check water pipe.

(2) water seal ring and water sealing pipe dislocation. The processing method is re-examine alignment.

(3) flushing, cooling is good. The processing method is check flush cooling cycle tube.

(4) mechanical seal has broken down. The processing method is check mechanical seal.

10. rotor moves a lot

(1) improper operation, operating conditions from pump design conditions. Processing methods: strict operation, making pump always works near the design conditions.

(2) balance weak. The processing method is dredge balance pipe.

(3) balanced disc and balance seat material don't meet requirement. The processing method is changing the material to meet the requirements of balanced disc and balanced seat.

11. produce water hammer

(1) because suddenly power off, causing system pressure fluctuations, appear eduction system negative pressure, and dissolved fluid bubble escaped makes pump or pipeline exist gas. The processing method is exhausting the gas.

(2) high pressure fluid column because suddenly power fail rapid flow backward, impact on pump export check valve plate. The processing method is the pump's unreasonable eduction system piping, pipeline accessories decorated undertake reform.

(3) outlet piping valve closed too fast. The processing method is slowly close the valve.

Centrifugal Pump