Common Fault Maintenance of HBT60 Concrete Pump

The motor starts under load

When the "Main Motor Start" switch on the operation panel is operated, if the main motor fails to start or only starts with difficulty, the pumping action will be automatically carried out.

First, check if the AC contactor is "burned out". If so, replace the contacts of the AC contactor. If not, disconnect the wires of solenoid valves A and B that control the pumping action, and re-operate the "main unit start" switch. If the fault phenomenon is eliminated, it indicates that the pumping switch is "directly connected". If the fault persists, check whether the solenoid valve core is "stuck". If so, solenoid valves A and B need to be replaced. If not, it is either that the main safety valve is leaking or the valve core is stuck and needs to be replaced.

Operate the pumping switch to stop pumping

Check the pressure of the main oil pressure gauge. If the pressure is zero, it indicates that solenoid valve A is not working, usually due to damage to the switch, circuit or solenoid valve coil. If the pressure display is too high (27.4MPa), it indicates that solenoid valve B is not working or the control oil circuit stop valve is not open.

Switch the reverse pump switch to prevent reverse pumping

Check the pressure of the main oil pressure gauge. If the pressure display is normal (the reversing oil pressure is 10.5 MPa), then neither solenoid valves C nor D are working. It is usually due to damage to the switch or the circuit. If the pressure display is too high (27.4 MPa), only one of the two solenoid valves, C and D, is working. The maintenance of the solenoid valve is the same as the previous example.

The stroke of the conveying piston is automatically shortened

First, check whether the travel regulating valve is tightened and closed. If not, it needs to be tightened. If so, disassemble the valve core of the valve to check if the seal is damaged. If so, replace the valve core sealing ring. If not, reinstall the valve core and check whether the unloading pressure of the safety valve in the closed circuit is lower than 12MPa. If it is, adjust it accurately. If not, it indicates that the seal of the main hydraulic cylinder is leaking. If the main hydraulic cylinder cannot be repaired immediately, loosen the piston release valve a little to ensure that each stroke does not shorten and the pressure does not exceed 11MPa during reversing. This is the leakage compensation It can be used for emergency purposes for a short period of time.

The slide valve malfunctioned

Check whether the lubrication of the sliding rod is good. If not, clean the sliding valve assembly and repair the lubrication pipeline and its distribution valve. If so, check whether the adjustment pressure of the sequence valve is 10.5MPa. If not, adjust it accurately. If so, check whether the accumulator pressure is lower than 5.5MPa. If so, it must be recharged. If not, it is due to severe internal leakage in the spool valve hydraulic cylinder or incorrect connection of the oil pipe.

6. Water washing oil pump overheating and high-pressure leakage

Check if the water washing operation is in the right position. If not, adjust the length of the fork to the appropriate position. If so, it is caused by the unloading groove on the gear oil pump cover being installed in the wrong direction. The direction needs to be reversed.

When operating the water-washing pull rod, the water pump does not drain water or the pressure is low

First, check if the water-absorbing filter is clogged. If so, clean the filter. If not, check whether the water cylinder piston seal is damaged. If so, it needs to be replaced. If not, check whether the suction and discharge valves of the water pump are leaking. If so, tighten the spring or replace it. If not, check whether the unloading pressure of the water-washing safety valve is lower than 16MPa. If it is, adjust it to the correct level. If not, check whether the water-washing pull rod can be pulled to the working position. If not, adjust the length of the fork to the appropriate position. If so, it is due to internal leakage in the hydraulic cylinder of the water pump or incorrect connection of the oil pipe.

The oil temperature is too high

When the transfer pump is in normal operation, if the oil temperature exceeds 75℃, it is considered too high.

First, check if the heat dissipation net of the cooler is clogged. If so, it needs to be cleaned. If not, check whether the control oil circuit stop valve is fully open. If not, it needs to be completely loosened. If so, check whether the throttling screw in the pressure reducing valve assembly has fallen off. If so, reinstall it and tighten it. If not, it indicates severe leakage inside the main oil pump. At this point, listen carefully and you will find that the main oil pump makes a considerable noise. The friction pair needs to be replaced or the entire main oil pump should be replaced.

Finally, it should be noted that before each disassembly of hydraulic components for maintenance, the machine must be stopped and the manual directional control valve operated to eliminate residual pressure to prevent injury from high-pressure oil.