Causes of mud pump failure and solutions:
1. No water after startup
1. Reason analysis
(1) There are sand, cement agglomerates, and debris around the suction valve, and the ball valve cannot be closed;
(2) The O-ring cut edge on the suction valve seat leaks;
(3) The three drain plugs under the pump head are not fitted with gaskets or not tightened, resulting in air leakage;
(4) The suction channel and pump cavity are filled with air due to the new pump or the stopping time for too long;
(5) Blockage in the suction channel or suction port.
2. Solution
(1) Remove all debris around the suction valve and flush it with clean water;
(2) Replace the O-ring of the valve seat;
(3) Check the three water drain plugs under the pump head, if there is no sealing gasket, replace it, and tighten it if it is loose;
(4) Loosen the unloading valve to release the air, or open the air by one gear slower to start the water supply;
(5) Clear the blockage of the suction channel.
2. The motor does not rotate
1. Reason analysis
(1) The diesel engine speed of the main pump station is too low, the fuel supply is insufficient, and the supply pressure of the hydraulic system is too low;
(2) The hydraulic system of the mud pump supplied by the main pumping station is faulty or the pressure adjustment of the overflow valve in the system is low and the internal leakage is serious, and the supply pressure is insufficient;
(3) The hydraulic motor is faulty;
(4) The gear shifting gear is not in place, and the positioning device is not locked out of gear (that is, the neutral gear is changed);
(5) The crankshaft or connecting rod is faulty or damaged.
2. Solution
(1) Increase the speed of the diesel engine at the main pump station (n is greater than or equal to 1500 r/min), increase the fuel supply of the motor, and increase the effective working pressure of the hydraulic system (above 10MPa);
(2) Check and eliminate the faults in the hydraulic system of the mud pump (to solve with the maintenance personnel of the main engine);
(3) Check and discharge the hydraulic motor failure on the mud pump;
(4) The shift gear is in place and the positioning device is locked again;
(5) Check and replace damaged parts.
PN mud pump
3. Large fluctuations in flow and pressure
1. Reason analysis
(1) The sand, mud and other debris accumulated on and around the suction ball valve, the ball valve is not closed tightly;
(2) The O-ring cut edge on the suction valve seat leaks;
(3) Excessive wear or damage of the piston, suction and slurry leakage;
(4) There is a seal failure in the suction channel, or the pump head is not tightened or the seal is missing, causing air leakage.
2. Solution
(1) Remove and clean all debris around the suction valve;
(2) Replace the O-ring seal on the valve seat;
(3) Tighten the piston adjusting screw sleeve or replace the piston;
(4) Check all the seals of the suction channel and eliminate them.
Fourth, the pump body is noisy
1. Reason analysis
(1) The gear shifting gear is not in place, and the positioning device is not locked;
(2) The bearing clearance between the primary and secondary shafts and both ends of the crankshaft is too large and not adjusted properly;
(3) Excessive wear of the bearing bushes of the connecting rod and the big end, and the clearance is too large;
(4) The crankshaft or connecting rod or even individual gears are deformed or damaged.
2. Solution
(1) The gear shift must be in place and the positioning device must be locked;
(2) Adjust the bearing clearance between the primary and secondary shafts and the two ends of the crankshaft to ensure stable operation;
(3) Adjust the gasket or replace the bearing bush in the two halves of the connecting rod;
(4) Check or replace damaged parts.
PNJB mud pump
5. The crankcase body temperature rises too high
1. Reason analysis
(1) The oil level in the tank is too high, and the oil is injected too much;
(2) The large-end bearing bush of the connecting rod has a small gap and no oil film is formed. Dry friction causes excessive temperature rise;
(3) The bearing clearance between the primary and secondary shafts and the two ends of the crankshaft is too small and too tight, which will cause a temperature rise.
2. Solution
(1) Lower the oil level in the box to the calibrated position and drain the excess oil;
(2) Add a 0.1mm gasket (added on both sides) at the joint of the two halves of the big-end connecting rod to ensure that there is a certain gap between the bearing bush and the crankshaft to form a sufficient oil film;
(3) Adjust the bearing clearance of the primary and secondary shafts and both ends of the crankshaft to a reasonable level.
6. The bearing temperature is too high
1. Reason analysis
(1) The bearing lubricant is insufficient or too dirty;
(2) Bearing wear or damage;
(3) Wear of the bearing and shaft fitting.
2. Solution:
(1) Supplement or replace lubricating oil;
(2) Adjust or replace bearings;
(3) Repair the journal or replace the bearing.
Seven, other failures
1. There is oil or slurry leakage in the pump drain hole
(1) Reason analysis: the J-shaped sealing ring in the sealed box is damaged or the oil tank fills over the calibrated oil level, the oil fills too much, and the piston is loose or damaged.
(2) Solution: replace the J-shaped sealing ring in the sealed box, discharge the oil tank oil to the calibrated oil level; adjust the adjustment screw sleeve of the compression piston or replace the piston.
2. The pressure gauge does not display
(1) Reason analysis: The oil in the buffer has leaked or no oil has been injected, and the rubber diaphragm in the buffer is damaged.
(2) Solution: Tighten the pressure gauge, fill the buffer with oil, and replace with a new rubber diaphragm.
3. There is leakage slurry at the cylinder head or valve cover
(1) Cause analysis: damage to the cylinder head or valve cover O-ring.
(2) Solution: Replace the O-ring of the cylinder head or valve cover, pay attention to adding butter before installing, to prevent the O-ring from cutting edges.
4. There is slurry leakage in the leakage hole of the safety valve or the safety valve does not operate
(1) Cause analysis: the steel ball or valve hole on the safety valve is damaged; the steel ball and valve seat on the safety valve are rusted; sand particles are accumulated around the ball valve on the safety valve, and the slurry is agglomerated.
(2) Solution: replace the steel ball or valve seat; remove the rust on the steel ball and valve seat; remove and clean the sundries of the safety ball valve.
5. The pressure of the pump cannot go up
(1) Reason analysis: The diesel engine speed of the main pumping station is low and the fuel supply is insufficient, resulting in insufficient flow of the water pump and the pressure cannot rise.
(2) Solution: Increase the diesel engine speed of the main pump station (n is greater than or equal to 1500 r/min), increase the motor oil supply, increase the water pump flow, and then increase the pressure; unscrew the pressure gauge and fill the buffer with oil or After replacing the rubber diaphragm, fill it with engine oil.
The reasons and solutions for the failures that often occur in mud pump operations are listed above. The equipment failures caused by specific reasons in the use of mud pumps are different. Reasonable use and maintenance of the equipment can extend the service life of the equipment.