In a construction site in Dalian after a overhaul of the "S" pipe valve concrete pump due to failure and stop working, the fault phenomenon is: the main oil pressure is not and no commutation; distribution valve system does not hold pressure; when the pump is given Sent, anti-pump and jog signal, the corresponding intermediate relay and plug lights are action and good contact, but the system did not respond. According to the above analysis of the following:
First determine the electrical no problem, so from the hydraulic search. Because it is overhauled pump, the hydraulic parts may lead to failure, so according to the hydraulic principle one by one analysis.
Figure 1 can be divided into the main oil system, distribution valve oil system and mixing oil system. The main oil system is supplied by the plunger pump 3, and the oil is driven by the electro-hydraulic reversing valve 9 to drive the master cylinder 19. When the electro-hydraulic directional control valve 9 and the electromagnetic relief valve 8 are not energized, the electro-hydraulic directional control valve is in a neutral position and the electromagnetic relief valve is also in a relief state. Oil from the main oil pump 3 is returned to the tank through the radiator 21.
The reason why the main oil line is not commutated may be:
(1) Electro-hydraulic valve 9 pilot spool or hydraulic spool in the card, leading to the main valve can not move for the commutation. (2) One-way throttle valve 10 blocked, the control oil is cut off, can not be reversed. (3) electromagnetic relief valve 8 adjust the pressure is too low, even if the main valve 9 is reversed, the oil pumped out of the pump will not enter the main tank, but directly overflow back to the tank. (4) There is no pressure oil in the tank due to low level or due to the main oil pump 3. (5) distribution valve fault, control the oil pressure is not generated.
After careful examination of the above possible reasons, electro-hydraulic valve spool 9 with good, free activity; unidirectional throttle 10 channel intact; relief valve 8 to adjust the pressure normal; tank liquid level to meet the requirements and The main pump is normal; there is pressure on the distribution valve circuit, but no packing, which may be the key reason for the problem.
Dispensing valve oil by gear pump 4.1 oil, the oil through the pilot unloading valve 5 to the accumulator 11 and the electro-hydraulic valve 13, driving the swing cylinder 18 work. Because the electro-hydraulic valve 13 hydraulic slide valve function is O-type, so when the solenoid valve is not energized, the hydraulic valve of all channels are cut off. Due to the pilot unloading valve 5 within the one-way valve, system pressure can be achieved while the pump unloading. In addition, the distribution valve has a pipeline leading to the main electro-hydraulic valve tubing 9, used to promote the hydraulic valve spool.
The reason why the distribution valve oil line does not hold pressure is shown in Table 1.
The inspection found that: the pilot unloading valve 5 check valve spool is metal powder stuck, loss of one-way effect, after removal of the spool back; also found that the shut-off valve is not fully closed 12, after the restart pump and found that Failure is not ruled out. The analysis, caused by the control of oil leakage is due to the electro-hydraulic valve) itself. It can be known from the principle that the control oil of the electro-hydraulic directional control valve 13 is internally discharged and the electro-hydraulic directional control valve 9 is externally controlled. Its internal structure shown in Figure 2.
Figure 2 shows the internal structure of the electro-hydraulic directional control valve, there is a M6 plug (DD cross section) between the inlet port P of the electro-hydraulic directional control valve and its control port X. If the control of the electro-hydraulic directional control valve Oil is the internal control leakage, the P, X is the same between the mouth, if the hydraulic control valve oil is outside the control leakage, the P, X between the mouth of the barrier. So concluded that this fault on the electro-hydraulic valve 6 6 plug. After disassembly found, M6 wire plug off, but not in the valve housing, and finally found in the radiator inlet. After treatment, restart the pump, the fault has been ruled out.
Unlike traditional windshield wipers, the boneless windshield wipers do not have the support of the skeleton. Instead, they are assembled with 4 parts including wiper strips, boneless wiper blades, wiper sheaths, and plastic parts. Under this design, not only the wiper is more flexible, compared with the traditional wiper, the force and wear are more uniform, which can achieve a better wiping effect, and it also further improves the driving safety.
Window Wipers,Piaa Wiper Blades,Windshield Wiper Replacement,Windshield Wiper Blades
Taishan Yuanjin Auto Parts CO., LTD , https://www.tsyuanjin.com