Views: 302 Author: Site Editor Publish Time: 2021-07-05 Origin: Site
This article briefly describes the analysis of the damping characteristics of the pilot circuit of the balance valve for reference for hydraulic engineers' selection and design. At the same time, it helps engineers choose the right hydraulic ball valves and hydraulic shutoff valves.
This design type has a low cost and is suitable for occasions where the load is small and relatively stable.
Because the volume of the control chamber of the balance valve is small, and the flow into and out of the control chamber is small, the orifice diameter must be small to be effective. If the orifice is too small, it is easy to be blocked by pollution particles. The orifice is generally 0.4-0.8mm. Increasing damping is equivalent to increasing filtering. If the size of the orifice cannot be determined, adjustable damping can be used and determined by the experiment. Adjustable damping is generally a special form of thread gap, and the damping size can be changed by screwing in the adjusting screw to the length of the screw hole. Because this kind of orifice has no directionality, it will prolong the response time, and the balance spool will open and close slowly. We recommend using KHB Hydraulic Ball Valve with Mounting Hole and KHB3K 3-Way Hydraulic Ball Valve, which are easy to use and have a long service life.
The balance valve will open slowly and close quickly. The balance valve will open slowly to achieve a smooth load drop. The balance valve closes quickly to ensure that the load quickly stays at the required position.
The partial pressure through the hydraulic half-bridge can reduce the fluctuation of the pressure in the driving chamber of the balance valve, thereby significantly improving the stability of the system operation. But it also has an impact. On the one hand, through the orifice partial pressure, the pilot ratio is reduced, and higher pressure is required to open the balance valve, which will change the system operating point and increase energy consumption. On the other hand, through the partial pressure of the orifice, a part of the oil will be lost. In the fixed pump oil supply system, it may slightly reduce the operating speed of the actuator. With a digital pressure switch and liquid filled pressure gauge, we can better monitor and adjust the pressure.
The above damping characteristics are very sensitive to viscosity changes caused by oil temperature changes. VEM damping can reduce the sensitivity of viscosity changes caused by oil temperature changes. The set pressure of valve 2 is 350 bar, the pilot ratio of valve 2 is 13:1, and the set pressure of valve 1 is assumed to be 16.5 bar.
We can use oil pressure testers and vacuum pressure gauges to accurately measure pressure. When the balance valve is opened, the P port supplies oil, and the pressure is less than 16.5bar. The pilot oil quickly fills the pilot oil chamber, and then the pilot pressure is increased to 16.5 bar to change the direction of valve 2. The balance valve opens slowly and steadily, so that the balance valve responds quickly and opens smoothly. When the balance valve is closed, the P port quickly releases pressure through valve 1, so that the balance valve closes quickly.
Follow us to learn more about KHB 2-Way Hydraulic Ball Valve and High-Pressure Hydraulic Ball Valve.
