Parker Gear Pump - Gear Pump Flow Failure: Reasons
Parker Gear Pump address several potential causes of gear pump flow failure:
1The fixed pressure reducing valve spool is dead in the fully closed or small opening position, so that the oil outlet (P2) has no oil or very little oil passes through the throttle valve. At this point, the rinsing should be removed and deburred so that the pressure reducing valve core can move flexibly.
2 The speed control valve inlet and outlet ports are reversed, and the gear pump will tend to close the pressure reducing valve core, causing the throttling effect to fail. Q-type and QF-type valves are easy to install due to the symmetry of the holes on the mounting surface. On the bottom surface of the general plate speed control valve, P1 (import) and P2 (outlet port) sound samples are marked at each port, which can be carefully identified and cannot be connected incorrectly. It is difficult to install the positioning pin on the bottom surface of the inlet speed control valve.
3 The speed difference between the inlet and outlet of the speed control valve is too small, resulting in failure of flow regulation. For Q-type speed valves, the inlet pressure is greater than the outlet pressure O. 5MPa, the inlet pressure of the QF valve is greater than the outlet pressure IMP. At this point, the flow can be adjusted. The adjusted output flow is unstable. The constant pressure difference pressure reducing valve spool (Fig. 6-134) is stuck by dirt. The valve end screw plug can be disassembled, and the pressure reducing valve core is taken out from the valve sleeve to perform deburring cleaning and precision inspection. In particular, it is necessary to pay attention to whether the size of the pressure reducing valve core is concentric, and the defective person is repaired and replaced.
4. The fixed pressure difference valve spool hole a is blocked or the small hole on the valve sleeve is blocked by dirt, so that the pressure difference Ap of the throttle valve inlet and outlet is not constant and the flow is unstable. At this time, the ~lmm thin steel wire can be used to pass through the valve sleeve and the feedback hole on the valve core, or blown through compressed air. The inlet and outlet ports are easy to reverse.
5. The one-way valve spool in the one-way speed regulating valve is not in close contact with the valve seat, and there is an internal leakage.
6. The spring of the pressure reducing valve is leaked, or the spring is broken and misplaced. Can be refilled or replaced.
7. The large amount of internal and external leakage of the speed control valve leads to unstable dispersion. The leak should be treated.
8. The inlet and outlet ports are reversed, so that the speed control valve is like a general throttle valve without pressure feedback compensation. There is no positioning pin on the installation surface of the domestic speed control valve. Pay special attention not to let the inlet and outlet ports reverse.
9. No flow output at the speed control valve outlet, the actuator does not operate. 1 The throttle valve spool is stuck in the closed position. Detachable cleaning. 2 The constant pressure difference pressure reducing valve spool is stuck in the closed position. Detachable cleaning. The cause of the fault and the troubleshooting method are the same as the throttle valve.
