Created on:2021-07-05 11:09

Hydraulic failure analysis of rubber mixer

Hydraulic failure analysis of rubber mixer

(1) Fault analysis

As a high-pressure, high-power and complex hydraulic system, the hydraulic system of gk400 internal mixer will inevitably have some faults. In particular, the use of closed-loop proportional valve, involving a variety of microelectronic technology, which requires maintenance personnel must have a certain understanding and mastery of the relevant professional. As far as the actual situation is concerned, when a certain kind of fault occurs, it often leads to other faults, so the whole system is often in a comprehensive abnormal state, that is, different fault forms appear on different components, so the maintenance personnel must carry out specific analysis according to the specific phenomenon, and find out the fault hydraulic components through screening and elimination.

The following steps are usually used to analyze and diagnose the hydraulic system fault of gk400 internal mixer.

① According to the actual phenomenon and the schematic diagram of the hydraulic system, according to the function of each hydraulic element, find out the hydraulic element that may cause the fault phenomenon.

② According to the use of each hydraulic component, the previous maintenance situation and the difficulty of inspection, the components that are easy to inspect are placed in the front, those that are not easy to disassemble (such as top bolt hydraulic cylinder) and those that do not have the conditions of disassembly and assembly (such as closed-loop proportional valve) are placed in the back.

③ According to the specific situation of each component, different methods are used to detect in turn, and through analysis and judgment, the faulty component is found out.

④ Replace or repair the failed components. After confirming that all the components without failure have recovered to the state before inspection, start the system and conduct test run.

For example, in the process of use, gk400 internal mixer hydraulic system often appears oil temperature alarm, resulting in the machine can not work continuously, affecting production. The specific phenomena of the fault are: high oil temperature, frequent start of variable displacement pump; The storage period of the accumulator is shortened.

According to the hydraulic schematic diagram, it is considered that the following reasons may lead to the failure phenomenon, and they are arranged in the order from easy to difficult

① The overflow pressure of the system is changed and the overflow pressure is too low;

② The cooler is blocked or the cooling water is insufficient;

③ The hydraulic cylinder of the upper jack bolt has serious internal leakage (the hydraulic cylinder of the lower jack bolt, lock pin and feeding door can be eliminated due to small flow, low working pressure and infrequent action);

④ The closed-loop proportional valve has internal leakage.

Through the inspection of the pressure gauge, it is confirmed that the system pressure can be reached, which indicates that there is no problem with the relief valve. By checking the flow rate of cooler and the current of circulating pump, confirm that there is no problem in circulating cooling system. When checking the hydraulic cylinder of the top bolt, keep the top bolt in a position for a long time. By checking the flow rate of the return oil and comparing the temperature of the inlet and outlet pipelines, it is confirmed that there is no problem with the hydraulic cylinder of the top bolt. Finally, the focus of inspection is put on the closed-loop proportional valve. During the inspection, it was found that the valve body temperature of the closed-loop proportional valve was high and accompanied by obvious noise. Therefore, it is concluded that the leakage of the closed-loop proportional valve causes the oil temperature alarm. After replacing the closed-loop proportional valve, the oil temperature alarm disappears.

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