In the hydraulic power unit 12v, the liquid flowing in the pipeline is often due to a very rapid change of direction and the sudden closure of the valve port, in the pipe away from the formation of a very high peak value, this phenomenon is called hydraulic shock.
First, the hazards of hydraulic shock
1, the impact pressure may be as high as 3 to 4 times the normal working pressure, so that the system components, piping, instrumentation and other damage.
2, Vibration and noise can cause connections to become loose. This may result in oil leakage. Consequently, the pressure valve may experience changes in pressure regulation, and the flow valve may experience changes in flow regulation. These issues affect the normal operation of the system.
3, Vibration and noise can cause loose connections, which may result in oil leakage. This, in turn, can lead to changes in pressure regulation by the pressure valve and flow changes by the flow valve. Such issues affect the normal operation of the system.hydraulic power unit 12v
Second, the reasons for hydraulic shock
1, the pipeline valve port quickly closed when the hydraulic shock.
2, When you suddenly brake moving parts that are in high-speed movement to a stop, you generate pressure impact (inertial shock).
For example, if the cylinder piston suddenly stops or reverses in the middle of its stroke, it may cause pressure shock. This happens because the main reversing valve is reversing too quickly. When the piston reaches the end of the cylinder and stops or reverses, the pressure shock becomes even more pronounced.
Third, the general approach to prevent hydraulic shock
To exclude or reduce the pressure impact from the sudden closure of the valve port, you can take the following methods.
1, slow down the closing speed of the reversing valve, that is, increase the reversal time. For example, DC solenoid valves generally produce less hydraulic shock compared to AC solenoid valves. Using electro-hydraulic directional valves with damping allows for adjustment of the damping to control pressure and flow. This, in turn, slows down the reversal (closing) speed of the main directional valve spool through the pilot valve. Hydraulic directional valves function similarly in this regard.
2, Increase the pipe diameter and reduce the flow rate to minimize the impact pressure. Additionally, shorten the length of the pipe and avoid unnecessary bending. Using a hose is also an effective method.
3, in the slide valve completely closed before slowing down the flow of liquid. To improve the structure of the control side of the reversing valve, consider modifying the spool with a rectangular V-shaped straight groove into a conical shape (with a half-cone angle of 2° to 5°). This adjustment significantly reduces hydraulic shock compared to the right-angle shape.
For cylindrical grinding machines, perform a pre-braking action first, then move the main reversing valve to the middle position. The pressure oil quickly fills the left and right chambers of the workbench cylinder (using a P-type main valve), resulting in a smooth, balanced stop without impact. Use an H-type directional valve for surface grinding machines. This setup connects the left and right chambers of the cylinder through an oil pool when the directional valve quickly jumps to the middle position, reducing the impact pressure during braking.
4, When the moving parts are suddenly braked, decelerated, or stopped, take preventive methods to reduce the hydraulic shock generated (such as in cylinders).
① In the hydraulic cylinder at the end of the stroke using a deceleration valve, due to the slow closure of the oil circuit and ease the hydraulic shock.
② can be set at the inlet and outlet of the cylinder fast response, high sensitivity small safety valves (direct-acting type), the adjustment pressure in the medium and low-pressure system, for the maximum working pressure of 105% to 115%. This applies to systems used in hydraulic gantry planers, guideway grinders, and similar equipment. In high-pressure systems, set the working pressure at 125% of the maximum working pressure. Systems in hydraulic machines commonly use this approach. This allows the impact pressure will not exceed the above adjustment value.hydraulic power unit 12v
③ The use of rubber hoses to absorb hydraulic shock energy.
④ In applications such as combined machine tools, set up a stroke throttle for fast-forward operation. Additionally, design the stroke with two angle bumps. By optimizing the angle design, you can prevent pressure impact caused by rapid changes in speed during work transitions. Alternatively, use a double-speed conversion to ensure that speed changes are not too abrupt.
⑤ Install a buffer device, such as a one-way throttle valve, at the end of the cylinder. This device controls the oil discharge speed at the end of the cylinder. As a result, the cylinder will come to a smooth and shock-free stop when it reaches the end.
(6) Set up accumulator at the position of the pipe journey which is easy to generate hydraulic shock to absorb the shock pressure.
⑦ In the cylinder return control oil circuit, set up a balance valve for vertical hydraulic presses and a back pressure valve for horizontal hydraulic presses. This setup controls the rapid descent or movement and mitigates forward shock. Additionally, properly adjust the back pressure to ensure optimal performance.
(8) Use hydraulic directional valves with damping, and adjust the damping accordingly. This involves closing the one-way throttles at both ends. Generally, this structure is used to design the main directional valve (hydraulic) within the control box of grinding machines.
⑨ If the cylinder hole clearance (gap seal) is too large, it can cause impact when the working pressure is set too high. Similarly, if the seal is damaged, the same issue may occur. To address this issue, you can either rework the piston or replace the piston seals. Additionally, properly reducing the working pressure can help eliminate the resulting impact phenomenon.
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