Plunger pump

This post was last edited by zdl1966 on 2016-10-22 at 15:46; the leakage and pressure release may be caused by rust on the plunger or poor sealing of the plunger’s components. When the pump is in self-priming mode, air leakage in the oil inlet pipeline, or significant leaks in components such as hydraulic cylinders, check valves, and directional control valves within the system, will all prevent the pressure from rising. This requires identifying the leak, tightening or replacing the seals, which will increase the pressure. If the relief valve is faulty or the set pressure is low, the system pressure will not rise; the pressure should be readjusted or the relief valve should be repaired. If a deviation between the cylinder block of the hydraulic pump and the distribution plate causes severe leakage, and in serious cases the cylinder block may crack, the mating surfaces should be re-ground or the hydraulic pump replaced.

May I ask how to distinguish between centrifugal pumps and plug flow pumps?

Just search on Baidu for images and schematic diagrams of [centrifugal pumps] and [plunger pumps], and you’ll find out

1. Severe plunger wear 2. Outlet leakage or low-pressure crossover

Is the check valve clogged? Is the packing severely worn? Is the plunger severely worn? Are there any issues with the plunger’s stroke?

Check the check valves at the inlet and outlet to see if they are clogged or leaking; clean them and try again

This post was last edited by “Never be mediocre” on October 24, 2016, at 11:52.
1. Inspect the inlet and outlet check valves:
1) Check whether the spring is broken; replace it if necessary.
2) Check whether the sealing surfaces of the valve core or valve seat are corroded or pitted, resulting in poor sealing; replace the valve core or valve seat if needed.
3) Check whether there are any foreign objects stuck inside the check valve; remove them if present.
4) Check whether the valve seat gasket is intact, or whether there is any leakage at the junction between the valve seat and the cylinder body. (This refers to situations where, with the inlet check valve closed, the medium inside the cylinder body leaks through the valve seat gasket toward the inlet.)； Check whether there is any leakage of fluid from the valve seat gasket toward the outlet when the outlet check valve is closed; in such cases, inspect and replace the gasket or the valve seat. Second, check whether there is any connection in the bypass lines adjacent to the inlet and outlet pipes; close the bypass valves. Third, if the inlet flow rate is insufficient: 1) Check whether the inlet filter is clogged; clean the inlet filter. 2) If the inlet pipe is blocked, check and clear the blockage. 3) Low liquid level in the tank before the inlet may cause air to be drawn in. Fourth, if the motor speed is insufficient: 1) If variable frequency control is used, increase the frequency. 2) In the case of belt drive, check for any abnormal noises or belt slippage; adjust the tightness of the belt and tighten it again

The simplest way is to look at the nameplate. Plunger pumps are also known as reciprocating pumps, and the type of pump is indicated on its nameplate; once you know what to look for, you can identify it at a glance