Chemical Pump Troubleshooting

Chemical Pump Troubleshooting

In coal chemical production, raw materials, semi-finished products and finished products are mostly liquids, and the preparation of raw materials into semi-finished products and finished products requires a complicated process in which the pump acts as a pressure flow for transporting liquids and providing chemical reactions. In addition, pumps are used to regulate temperature in many installations. Therefore, it is especially important to understand the common faults and solutions of various chemical pumps!

1 Pump does not absorb water

Failure analysis:

Ÿ The suction valve has debris or is not open, or the suction tube is blocked

Ÿ Poor sealing of piping system

Ÿ Intake air from the shaft seal

Ÿ Pump system failure

Solution:

Ÿ Open the suction valve to remove debris and clear the suction tube.

Ÿ Inspect the pipeline, especially the section pressure test connection flange, plugging.

Ÿ Replace the shaft seal and compress the packing seal

Ÿ Inspection and maintenance of pumping system

2 Pump can not start

Failure analysis:

Ÿ The prime mover has failed (including power);

Ÿ The pump is stuck;

Ÿ The stuffing box is pressed too tightly;

Ÿ The discharge valve is not closed.

Solution:

Ÿ Check the power supply and prime mover conditions;

Ÿ Re-drive the car to determine the coupling condition;

Ÿ Relaxing the filler;

Ÿ Pipe inlet and outlet valves, start again.

3 Pump does not drain

Failure analysis:

Ÿ Insufficient pump (or the pump gas is not drained);

Ÿ The pump is not turning right;

Ÿ The pump speed is too low;

Ÿ The filter screen and the suction pipe are blocked;

Ÿ The suction height is too high, or the liquid supply to the suction port is insufficient, causing a vacuum to be drawn.

Solution:

Ÿ Refill the pump;

Ÿ Determine the direction of rotation of the pump again;

Ÿ Check the idle speed of the motor, check the reduction ratio of the reducer, and determine whether the pump speed meets the design speed;

Ÿ Clean the filter and dredge the suction pipe;

Ÿ Adjust the suction line, higher than the inlet of the pump, and adjust the upper liquid supply system of the pump to ensure sufficient supply of the medium.

4 Pump interrupted after draining

Failure analysis:

Ÿ Leakage in the suction line;

Ÿ The suction side gas is not exhausted when the pump is pumped;

Ÿ The suction side is suddenly blocked by foreign matter, or the suction port filter is blocked;

Ÿ Dehydration of the suction tube, inhalation of large amounts of gas

Solution:

Ÿ Check the sealing of the suction side joint and the stuffing box;

Ÿ Refill the pump;

Ÿ Stop the pump, clean the filter element, and clear the suction line;

Ÿ Check if the suction line is broken and if the valve on the parallel inlet line is open (unusually used line).

5 Insufficient flow

Failure analysis:

Ÿ The net head of the system increases;

Ÿ Increased resistance losses;

Ÿ The mouth ring and the impeller are worn too much;

Ÿ Leakage elsewhere;

Ÿ The pump impeller is clogged, worn, and corroded.

Solution:

Ÿ Check the liquid level and system pressure;

Ÿ Check the pipeline and check valve for faults;

Ÿ Replace the ring and impeller;

Ÿ Check the shaft seal and other places;

Ÿ Cleaning, inspection, and exchange.

6 Lift is not enough

Failure analysis:

Ÿ Impeller mounted reverse (double suction pump);

Ÿ Liquid density, viscosity and design conditions do not match;

Ÿ The operating flow is too large.

Solution:

Ÿ Check the impeller;

Ÿ Check the physical properties;

Ÿ Adjust the valve and reduce the amount of sulfur.

7 Running overload

Failure analysis:

Ÿ Poor quality of the motive, fixed rotor friction;

Ÿ The impeller has friction with the grinding ring, the impeller and the pump casing;

Ÿ Increased liquid density;

Ÿ The packing is pressed too tightly or dry friction;

Ÿ Bearing damage;

Ÿ The speed is too high;

Ÿ The pump shaft is bent;

Ÿ The axial force balance device fails;

Ÿ Coupling misalignment or axial clearance is too small;

Ÿ The transport liquid is too viscous or too dense.

Solution:

Ÿ Check the replacement motor;

Ÿ Inspect the pump parts and repair them;

Ÿ Check density;

Ÿ Relax the packing and check the water sealing tube;

Ÿ Check and replace bearings;

Ÿ Check the prime mover speed and power supply;

Ÿ Correct the pump shaft;

Ÿ Check if the balance air and return pipe are blocked;

Ÿ Check the coupling and adjust the alignment;

Ÿ Replace the high power motor.

8 Pump vibration or noise exceeded

Failure analysis:

Ÿ The anchor bolts are loose or the base is not welded properly;

Ÿ The pump has cavitation (excessive flow, increased suction resistance or high liquid operating temperature);

Ÿ Pump surges (system net head pressure is higher than pump shut-off pressure)

Ÿ The impeller is damaged or has foreign objects.

Solution:

Ÿ Tighten the anchor bolts, re-inspect the base weld, and re-weld the base if necessary;

Ÿ Check the cause and eliminate the system;

Ÿ Check if the discharge is too high and if the pressure is too high;

Ÿ Disassemble the pump body and replace and remove foreign matter.

9 Bearing overheating

Failure analysis:

Ÿ Bearing assembly failed;

Ÿ Insufficient lubricating oil, poor oil quality or aging;

Ÿ Insufficient cooling water or open circuit.

Solution:

Ÿ Check and adjust

Ÿ Add enough oil or change oil;

Ÿ Increase the amount of water after inspection.

10 Axis seal overheating

Failure analysis:

Ÿ The packing seal is pressed too tightly;

Ÿ The mechanical seal is faulty.

Solution:

Ÿ Adjust the sealing pressure;

Ÿ Inspect, repair or replace the mechanical seal.