Check valves, also known as non-return valves or check valves, are used in hydraulic systems to prevent reverse flow of oil or in pneumatic systems to prevent reverse flow of compressed air.
Check valves are available in straight-through and right-angle styles. Straight-through check valves are installed in the pipeline using threaded connections. Right-angle check valves are available with threaded, plate-type, and flange connections. Hydraulically controlled check valves, also known as locking or pressure-maintaining valves, are similar to check valves in that they prevent reverse flow of oil. However, when reverse flow is required in the hydraulic circuit, the oil pressure can be controlled to open the check valve, allowing oil flow in both directions. Hydraulically controlled check valves use a tapered valve core, resulting in excellent sealing performance. When sealing an oil circuit, these valves can be used as a one-way lock to maintain pressure. Hydraulically controlled check valves can be used to control oil leakage in two ways: internal leakage and external leakage. The internal leakage type can be used in the oil circuit where there is no back pressure at the oil flow reverse outlet; otherwise, the external leakage type is required to reduce the control oil pressure.
