Introduction of check valve

Check valve is used to prevent the reverse flow of oil flow in hydraulic system, or used in pneumatic system to prevent reverse flow of compressed air, flowing fluid is only in the inlet and outlet medium cannot backflow.
Check valve has a straight-through and right Angle type two kinds. Straight-through one-way valve with screw thread connection installed in the pipeline.Right Angle type check valve has a threaded connection, flange connection plate connection and three forms.Hydraulic control one-way valve, also known as block valve or pressure valve, it is the same as the one-way valve, in order to prevent the oil flow.But need to reverse flow of oil flow in hydraulic circuit and available control oil pressure, open the valve, make the oil flow can flow in two direction.Hydraulic control one-way valve used cone valve core, so the sealing performance is good.In requirements when closed oil circuit, this valve is used as oil ChanXiangSuo tight and the holding role.Hydraulic control one-way valve control oil leak means has internal drainage and leaked type two kinds.In the oil flow reverse export without back pressure oil available internal drainage;Otherwise must be leaked type, in order to reduce the oil pressure control.

（source：http://www.kg-machinery.com/news/introduction-of-check-valve.html）