1. Abnormal pressure display.
1.1 Pressure supersystem pressure when opening valve.
The pressure gauge of the valve opening valve of circulating pump hydraulic control butterfly valve is above 19.5MPa (normal should be around 16MPa), and the qualified pressure gauge should be replaced. The pressure is still indicated at 19.5mpa, indicating the actual oil pressure of the system is high.
Cause analysis: according to the principle of hydraulic transmission, in the process of valve open and close, because there are no bar and rod cavity oil cylinder hydraulic stress area is different, in the case of equal force, the pressure on both sides of the piston will be different, in the rod chamber (which is close the valve cavity, the cavity hydraulic function area is small) of the oil pressure will increase and more than the system pressure, this is normal phenomenon.
In the operation of the valve, hydraulic abnormally elevated after fully open, analyze the causes for the valve fully open, electromagnetic directional valve closed, but because of inertia, the piston does not stop, there are still continue to open the valve of micro motion, because of the oil field has been cut off, thereby make a valve cavity pressure rise in an instant.
Measures: at this time to take in electrical control, general electromagnetic directional valve switch "delay" way to solve them, particular way is: open the valve, normally open valve, open the valve solenoid valves YV1 delay reset after 5 to 8 seconds, make the rod chamber of the hydraulic oil fully back to the tank, to avoid oil cylinder valve cavity is abnormal pressure booster, makes the cylinder valve cavity pressure gauge shows close to the system pressure, cylinder valve cavity pressure gauge shows close to zero. After shut valve: valve, electromagnetic valve YV3 blackouts, cut off the accumulator pressure oil, close the valve solenoid valve YV2 delay reset after 5 to 8 seconds, make the rodless cavity of the hydraulic oil tank back to fully, so as to avoid abnormal booster cylinder valve open cavity pressure, make the oil cylinder valve cavity pressure gauge shows close to the system pressure, cylinder valve open cavity pressure gauge shows close to zero.
When the hydraulic control butterfly valve is operated by the oil pump opening valve and the accumulator shutoff valve, YV3 does not delay the same time with YV1 or YV2. At the same time, the time delay valve will continue to operate after being in place, and there will be no improvement in the pressure abnormality.
1.2 The pressure is equal when the butterfly valve is on the switch position.
Hydraulic control butterfly valve in the closed position, equal to the pressure of valve open and close the valve, the main reason is as tall as a piston seal leakage cause oil pressure, oil motivation scheme, replacing oil motive piston sealing ring can be solved.
2. Common fault diagnosis and its elimination method: