Concrete pump valve control concrete pump truck hydraulic system when encountered failure how to deal with?
Mixing circuit system is widely used in concrete pump at present. The system consists of auxiliary pump (gear pump), superimposed relief valve, pressure relay, electromagnetic reversing valve and a two-way hydraulic motor. Mixing oil high pressure is controlled by a stack overflow valve, electromagnetic directional valve electromagnet DT power of opportunely, reversing valve left work, two-way hydraulic motor is rotating, drive the hopper in the blender to secondary mixing hopper in the concrete, and to the concrete cylinder feeding, when the mixer blade is the aggregate stuck inside the hopper, When the pressure in the system rises to the set pressure of the pressure relay, the pressure relay emits..
Mixing circuit system for the concrete pump commonly used at present, the system is composed of auxiliary pump (gear pump), superposition relief valve, pressure relay, electromagnetic reversing valve and a two-way hydraulic motor.
Mixing oil high pressure is controlled by a stack overflow valve, electromagnetic directional valve electromagnet DT power of opportunely, reversing valve left work, two-way hydraulic motor is rotating, drive the hopper in the blender to secondary mixing hopper in the concrete, and to the concrete cylinder feeding, when the mixer blade is the aggregate stuck inside the hopper, When the pressure in the system rises to the set pressure of the pressure relay, the pressure relay sends a signal to energize the electromagnet DT, the reversing valve works at the right position, and the hydraulic motor drives the agitator to reverse rotate, so that the aggregate stuck in the agitator falls off.
When the agitator reverses several turns, the electromagnet will automatically power off, the reversing valve will resume to the left, and the hydraulic motor will drive the agitator to turn positive.
Work Characteristics:
l) The main oil circuit system has the constant power function. The main pump provides pressure oil to the main oil circuit and the oil circuit of the distribution valve. The role of the auxiliary pump is to automatically adjust the variable mechanism of the main pump to ensure that the main pump is in a constant power state. When the pressure decreases with the change of load, the displacement of the main pump increases and the output power of the main pump is kept constant, which can make full use of the power of the motor, improve the working efficiency and prevent the motor from overload.
2) on the two main hydraulic cylinder set up a trust valve, the valve has three functions: when the hydraulic cylinder piston to the journey, the end of oil over the buffer one-way throttle valve to open the mouth, make part of high pressure oil by buffer oil in low pressure cavity, reduce the cavity pressure difference, the piston velocity is reduced, achieve the purpose of the buffer, and to prepare for the piston commutation; It can be used to fill the oil cavity to ensure the effective stroke of the piston. Signal oil through the control of the oil port to make the hydraulic change valve to complete the next pumping action of the concrete pump.
3) Connect the oil circuit of the distribution valve to the main oil circuit system. At present, the domestic hydraulic system of concrete pump is generally equipped with the best oil circuit system of the distribution valve. In order to ensure the powerful and rapid reversal of the distribution valve, the accumulator should be set in the system.
In the design of the hydraulic system, through the hydraulic reversing valve and electromagnetic reversing valve will distribute the valve oil and main oil system. Hydraulic reversing valve and electromagnetic reversing valve are combination valves. They are controlled by the pressure oil from the autonomous hydraulic cylinder, so that the pressure oil output from the main pump enters the two distributing valve cylinders alternately, realizing the reversing of the distributing valve, and meeting the requirements of the concrete pump for the rapid and powerful reversing of the distributing valve.
How to deal with the failure of hydraulic system of concrete pump truck? Common faults and treatment methods of hydraulic system of concrete pump truck:
1. No pressure or lack of pressure in the system
Problem: The relief valve is open, because the spool is stuck, can not be closed, the damping hole is blocked, the spool and the seat do not fit well or the spring fails.
Solution: Repair the spool and shell, clean the damping hole, replace the spring.
Problem: The spool of other control valves is stuck due to failure, causing unloading.
Solution: Find out the fault part, clean or repair, make the spool in the hair flexible movement.
Problem: Hydraulic components wear seriously, or seal damage, resulting in internal and external leakage.
Solution: Check the sealing of pump, valve and pipe connection, repair or replace the parts and seal.
2. Insufficient flow
Problems: The tank level is low, the oil viscosity is large, and the blockage of the filter causes your oil absorption resistance.
Solution: Check the liquid level, fill the oil, replace the hydraulic oil with appropriate viscosity, and ensure the diameter of the suction pipe.
Problem: hydraulic pump idling wear serious, performance decline.
Solution: Check the engine, hydraulic pump and hydraulic pump variable mechanism, if necessary, change the pump.
Problem: The return pipe is above the liquid level, and the air enters.
Solution: Check whether the pipe connection and seal are correct and reliable.
Problem: accumulator air leakage, pressure and flow supply is insufficient.
Solution: Check the accumulator performance and pressure.
3, leak
Problem: The joint is loose and the sealing is damaged.
Solution: Tighten the connector and replace the seal.
Problem: plate connection or flange connection joint surface screw pretightening force is not enough or sealing damage.
Solution: The pre-tightening force is greater than the liquid pressure, replace the seal.
Problem: The system pressure is longer than the rated working pressure of hydraulic components or auxiliary parts.
Solution: element shell pressure should not be greater than the allowable oil seal pressure, change the seal.
4, overheating
Problem: Improper pressure adjustment, long-term work under high pressure.
Solution: Adjust the pressure of the relief valve to the specified value, and improve the circuit if necessary.
Problem: Excessive power loss due to leakage and mechanical friction in the system.
Solution: Check the leakage, improve the seal, improve the machining accuracy of moving parts, assembly accuracy and lubrication conditions.
5, vibration
Problems: hydraulic pump, air inhalation, installation position is too high, oil absorption resistance, gear tooth shape accuracy is not enough, blade stuck and broken, plunger stuck and mobile is not flexible, parts wear make the clearance is too large.
Solution: Replace the seal of the oil inlet, the degree from the oil suction port to the pump oil suction port should be less than 500mm, ensure the diameter of the suction pipe, repair or replace the damaged parts.
Problems: The hydraulic oil, the liquid level is too low, the suction pipe insertion depth is not enough, the oil viscosity is too large, the filter is blocked.
Solution: Add oil, lengthen the suction pipe and dip to the specified depth, replace the viscosity hydraulic oil, and clean the filter.
Problems: overflow valve, blocked damping hole, excessive clearance between valve core and valve seat, spring failure.
Solution: Clean the damping hole, repair the gap between valve core and seat, and replace the spring.
Problem: Other spool does not move flexibly.
Solution: Wash and deburr.
Problems: Pipelines, slender pipelines, no fixed device, collision with each other, suction pipe and return pipe is too close.
Solution: The fixed device is set to expand the distance between pipelines and the distance between suction pipe and return pipe.
Post time: Nov-08-2022
