Spray system control for coal mine hydraulic supports: a check valve is installed between the P inlet and the A outlet, which is normally closed: when the hydraulic hole K is pressed to open the one-way valve, water from the P interface can flow through the A interface. The PSF2 type drain valve has two hydraulic holes, each of which can open the water shutter valve. Specifications Water inlet pressure: 2 - 8 MPa Open pressure: 2 MPa Material: medium carbon / stainless steel / 1 Cr18Ni9