Two-position four-way cartridge solenoid valve DHF08-241

In the hydraulic system, for some reason, the liquid pressure suddenly rises sharply at a certain moment, resulting in a high pressure peak. This phenomenon is called hydraulic shock.

1. Causes of Hydraulic Shock (1) Hydraulic shock caused by sudden closing of the valve.

As shown in Figure 2-20, there is a large cavity (such as hydraulic cylinder, accumulator, etc.) communicating with the pipeline with valve K at the other end. When the valve is opened, the liquid in the pipe flows. When the valve is suddenly closed, the liquid kinetic energy is quickly converted into pressure energy layer by layer from the valve, and a high-pressure shock wave is generated from the valve to the cavity. After that, the liquid pressure energy is transformed into kinetic energy layer by layer from the chamber, and the liquid flows in the opposite direction; Then, the kinetic energy of the liquid is converted into pressure energy again to form a high-pressure shock wave, and the energy conversion is repeated so as to form pressure oscillation in the pipeline. Due to the influence of friction in liquid and elastic deformation of pipeline, the oscillation process will gradually fade away and tend to be stable.

2) Hydraulic impact caused by sudden braking or reversing of moving parts.

When the reversing valve suddenly closes the oil return passage of the hydraulic cylinder and brakes the moving parts, the kinetic energy of the moving parts at this moment will be converted into the pressure energy of the closed oil, and the pressure will rise sharply, resulting in hydraulic impact.

(3) the hydraulic impact caused by the malfunction or insensitivity of some hydraulic components.

When the relief valve is used as a safety valve in the system, if the system overload safety valve cannot be opened in time or at all, it will also lead to a sharp rise in the system pipeline pressure and a hydraulic impact.

2, the harm of hydraulic impact

(1) The huge instantaneous pressure peak damages the hydraulic components, especially the hydraulic seals.

(2) The system produces strong vibration and noise, and makes the oil temperature rise.