Xuzhou Cylon Heavy Industry Machinery Co., Ltd.


Understand how the concrete vehicle pump hydraulic system is routinely maintained

Concrete truck-mounted pumps play an important role in project construction. Therefore, preventive maintenance is carried out in advance during equipment maintenance to achieve good performance of the whole machine, which plays an important role in ensuring smooth construction.

The following are some of the common problems in the application of concrete on-board pumps . The operators can refer to them in order to make agile discriminating and eliminate problems, and prevent the occurrence of delays in construction and safety accidents.

Common problems

1. The system is stress free or lack of pressure

◇The overflow valve is open because the valve core is stuck, it cannot be closed, the damping hole is blocked, the valve core and the valve seat are not well cooperated or the spring is invalid.

Method: repair the valve core and the casing, clean the damping hole, replace the spring

◇Other control valve spools are stuck due to problems, causing unloading

Method: find the faulty part, clean or repair, make the valve core move in the valve body sensitive

◇The hydraulic components are severely worn, or the seal is damaged, forming internal and external leakage.

Method: Check the tightness of the joints of the pump, valve and piping, repair or replace parts and seals

2. Lack of traffic

The liquid level of the sputum tank is too low, the viscosity of the oil is large, and the filter blockage causes a large oil absorption resistance.

Method: check the liquid level, make up the oil, replace the hydraulic oil with the appropriate viscosity, and ensure the diameter of the suction pipe.

◇The hydraulic pump idling wear is severe and the performance is degraded.

Method: check the engine, hydraulic pump and hydraulic pump variable mechanism, change the pump if necessary

◇The oil pipe is above the liquid level, the air enters

Method: Check if the pipe connection and sealing are correct and reliable

◇ Accumulator leaks, lack of pressure and flow supply

Method: View accumulator performance and pressure

3. Leaking

◇The joint is loose and the seal is damaged.

Method: tighten the joint and replace the seal

Seesaw type joint or flange joint surface screw pre-tightening force or seal damage

Method: The pre-tightening force should be greater than the hydraulic pressure, replace the seal

The pressure of the helium system is longer than the extra working pressure of hydraulic components or accessories.

Method: The pressure inside the component housing should not be greater than the allowable pressure of the oil seal.

4. Overheating

◇The pressure is not properly adjusted, and it is working under high pressure for a long time.

Method: Adjust the relief valve pressure to the regular value and improve the circuit if necessary

In the ◇ system, power loss is excessive due to leakage and mechanical conflict.

Method: check for leaks, improve sealing, improve machining accuracy, assembly accuracy and smooth conditions of moving parts


◇Hydraulic pump: Intake air, installation orientation is too high, oil absorption resistance is large, gear tooth shape accuracy is not good, the blade is stuck and cracked, the plunger is stuck and moving is not sensitive, and the parts wear make the gap too large

Method: Replace the inlet seal, the suction port to the pump suction port height should be less than 500 mm, ensure the suction pipe diameter, correct or replace the damaged parts

◇Hydraulic oil: The liquid level is too low, the suction pipe is not inserted into the liquid surface depth, the viscosity of the oil is too large, and the filter is clogged.

Method: Refuel, the oil pipe is lengthened to the regular depth, replace the suitable viscosity hydraulic oil, clean the filter

◇Overflow valve: The orifice is blocked, the valve core and the valve seat cooperate too much, and the spring is invalid.

Method: Clean the damping hole, repair the gap between the valve core and the valve seat, replace the spring

◇ Other spools are not moving

Method: cleaning, deburring

◇ Pipe: The pipe is slender, there is no fixed equipment, and each other is hit. The suction pipe is too close to the return pipe.

Method: Refer to the installation of fixed equipment, expand the interval between pipes and the interval between the suction pipe and the return pipe

◇Electromagnet: The electromagnet is poorly welded, the spring is too hard or damaged, and the spool is stuck in the valve body.

Method: welding from the beginning, replacing the spring, cleaning and researching the valve core and valve body

◇Mechanical: The hydraulic pump and the motor coupling are not concentric or loose, there is impact when the moving parts are stopped, the commutation is short and the damping is small, and the motor oscillates.

Method: adhere to the pump and motor shaft concentricity is not more than 0.1 mm, use elastic coupling, tighten the dowel, set damping or buffer equipment, motor for balance treatment

6 shock

◇ Accumulator inflation pressure is not enough

Method: Inflate the accumulator

◇The pilot valve and the reversing valve are not braked and the buffer is slow.

Method: reduce the angle of the brake cone or increase the length of the brake cone, correct the buffer equipment

Analysis of the case of pumping problems

1 pump car electrical schematic

2 boom can only be rotated unilaterally or not at both ends

Example: A 2006 37-meter pump truck suddenly presents a boom near the pumping process. Under the remote control condition, the left and right sides can only rotate unilaterally or both ends.

Analysis of problems

1. Electrical aspects:

Is the arm frame rotation limit switch damaged?

◇ boom rotating solenoid valve is in a state of power and damage

◇ Is the relay damaged?

2, hydraulic aspects:

◇ boom rotating multi-way valve block problem

◇ boom rotating balance valve problem

◇ reducer motor problem

◇ Reducer damage

Troubleshooting process:

1. Electrical:

◇ Check if the I2.6 and I2.7 lights are on. If they are not lit, the boom rotation limit switch is not damaged. If it shines, let's take the appropriate wiring and see if the problem is still the same: normal, it is the limit switch near the switch limit to clarify its damage. If it is still there, there are other problems with the near-switch damage.

◇ Check that the boom rotary solenoid valve is energized or not powered when the boom is not rotating. Check if there is output in Q3.0 and Q3.1 (check if there is voltage output on line 69 and 70 of the motion boom). There is no output to check whether the K31, K32 relays, and modules are damaged. There is output, the solenoid valve is not powered to check if there is a problem with the broken line. The solenoid valve is energized, check whether the resistance of the solenoid valve is normal, and the abnormal solenoid valve coil is damaged.

◇ Check if the rotary solenoid valve spool is normal. Check the spool if the 24U voltage is on the solenoid valve. There is no action and the spool is damaged.

If the electrical aspect is normal, perform hydraulic analysis.

2, hydraulic:

◇ Check if the multi-way valve head is damaged. It will exchange the oil pipe with the No. 1 boom multi-way valve to see if the rotation is not moving. It is proved that the multi-way valve head problem is caused to see if the damping hole inside is blocked.

◇ Look at the rotary balance valve and clean the valve plug to see if it is issued.

◇ Look at the hydraulic motor to see if it can rotate, does not rotate, and the motor is damaged.

◇Reinstall the reducer to check if the inner bearing is damaged and damage the replacement bearing.

◇ After the pump is viewed, the problem is that the rotating solenoid valve coil is burnt out. After replacing the solenoid valve, the device is normal.

Summary: The single or non-rotation of the boom is a common problem for pump trucks. It is generally presented in electrical terms. Therefore, it is easy to remove the problem from the electrical to the hydraulic pressure.

3 boom control legs can not move when the remote control is remote

Fault phenomenon:

Example: A small SY5310-37 meter small displacement pump truck can not move when the remote control is remote control, and the pumping is normal.

Analysis of problems

1. Boom valve electromagnet, bypass valve electromagnet

2. Expansion module Q2.7 is damaged

3. Chip relay KA30 burned out

4. Boom valve, bypass valve issuing

5. Multi-way valve three-way flow valve is issued or damaged

Sweep process:

1. Use a multimeter to measure whether the output voltage of Q2.7 is normal, such as normal at around 25V. If not, the module is damaged.

2. Check the bypass valve electromagnet, whether the arm valve solenoid is energized, and find that the KA30 chip relay 68# line has no electricity. The KA30 relay 68# line can be used after short-circuiting Q2.7, and the KA30 relay can be replaced from the head. After normal. If it is powered, check the bypass valve solenoid, whether the coil valve solenoid resistance is normal, if it is not normal, replace it; if it is normal, open it to see if the valve core has card issuance.

3. The above is normal. Check whether the multi-way valve three-way flow valve is issued and damaged. If the card is issued, it will be sorted out and replaced if it is damaged.

终This pump is finally overhauled. The problem is that the KA30 relay is damaged. After replacement, the equipment is normal.

Summary: The pump center relay uses a chip relay, and the bypass valve and the boom valve are all controlled by KA30. For some new pump bypass valves, the boom valve is controlled by two relays, and should be distinguished and noticed in the process of troubleshooting.

4 mixing pressure is not normal and can not be adjusted

Fault phenomenon

A 37-meter pump truck of Condensate Co., Ltd. pumped for a period of time and found that the mixing was weak or sometimes stopped, and the pressure could not be adjusted.

Analysis of problems

1. Mixing motor damage

2, bad mixing and overflow valve damage

3, gear pump loss

Troubleshooting process:

1. Regulate the mixing pressure. If it is normal, the mixing pressure is too low. If it is not normal, it may be the mixing valve or other faults. Disassemble the relief valve and observe if the regulator spring is cracked. Cracking replaces the spring.

2, check the mixing motor unloading oil pipe to see if the heat is abnormal or abnormal. If there is a replacement motor.

3. When the upper part has been removed, the reversing gear pump output pipe and the mixing gear pump output pipe will be adjusted to see if the mixing is normal. If it is normal, the mixing gear pump will not be able to withstand the pressure and replace the gear pump.

齿轮 When the fault was found, the gear pump was severely worn, and the equipment was working normally after replacing the gear pump.

Summary: This problem is a hydraulic system problem. Just familiar with the hydraulic circuit, you can find out the cause of the problem by careful analysis.

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