The hydraulically controlled exhaust valve is commonly used in hydraulic circuits, but its characteristics must be carefully considered during application. Failure to do so can lead to circuit instability, especially in high-pressure systems where the valve may open in reverse. When the pressure at the P2 port is very high, this can cause control pressure fluctuations, hydraulic shocks, and noise. To address these issues, a hydraulically controlled exhaust valve with a spool unloading function is often employed. This type of valve helps reduce pressure spikes and improves system stability.
The key feature of a hydraulically controlled exhaust valve is that, when no pressure oil is present at the control port K, flow is only allowed from port P1 to P2, and not in the reverse direction. However, when pressure oil is applied to the control port K, it activates the control piston, which pushes the ejector rod. This action opens the unloading valve core and allows the main valve core to open, connecting ports P1 and P2. As a result, oil can flow freely in one direction, reducing hydraulic shock and improving the overall performance of the system. Despite these benefits, high-flow and high-pressure systems may still experience some impact or noise.
Hydraulically controlled venting valves are frequently used in pressure-holding, pressure-relief, and locking circuits. Due to the compressibility of oil and the elasticity of system components, energy can be stored in the system under pressure. When the pressure is released, this stored energy is suddenly discharged, causing shocks and vibrations. For example, when a reversing valve shifts from the neutral position to the left, the pressure in the upper chamber of a hydraulic cylinder increases rapidly. At this point, both the unloading valve and the main valve open simultaneously, allowing pressure oil to escape quickly through the exhaust valve, leading to sudden pressure relief, shock, and noise.
To mitigate these issues, an improved hydraulic circuit was introduced. A throttle valve was added to the system, ensuring that the unloading valve opens first before the main valve. This throttling mechanism provides better control over the flow rate, ensuring stable minimum flow, easy adjustment, minimal leakage, and reduced sensitivity to temperature and pressure changes. By adjusting the throttle valve, the pressure relief time in the upper chamber of the hydraulic cylinder can be extended, enhancing the system’s ability to manage pressure surges and reducing impact and noise on components.
This improvement was also applied to high-pressure, high-flow hydraulic control exhaust valve circuits, and the results met all required performance standards without affecting the speed of the control piston. The enhanced design ensures smoother operation and greater reliability in demanding applications.
[Tip]: With the continuous advancement of valve technology, the range of applications for valves has expanded significantly. Corresponding valve standards have become increasingly essential. Shanghai Jiade Valve Manufacturing Co., Ltd., with over 20 years of experience, is a leading manufacturer of general valves in China. It supplies gate valves, globe valves, ball valves, butterfly valves, and hydraulic control valves to industries such as petroleum, chemicals, metallurgy, power generation, construction, heating, and water supply. The company is well-known for its quality and reputation, with products in high demand both domestically and internationally.
Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
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