Check Valves allow medium to flow in one direction only, stop medium which flow in opposite direction .usually these valve work automatically. Under the action of pressure of fluid which flow in one direction, the disc open. When fluid flow in opposite direction .the fluid is cut down by the pressure of fluid and self-gravity
The check valve include swing type and lift type . Swing check valve have an articulated mechanism and a disc which leant on surface of slop seat freely . The disc is connected with articulated mechanism to make sure disc can reach right place on seat every time .so that disc have enough space to swing and can contact with seat veritably in full-scale . According to the requirement , disc can be made from metal , metal embed in leather or rubber or compound .when check valve open completely ,fluid pressure have little resistance, therefore the pressure drop through valve is relative small.
Disc of lift check valve is on the seal face of seat .It?