API Cast Steel Check Valve
Stainless steel+flexible graphite wounded gasket is used for Class 150 and Class300 check valve,Stainless steel+flexible graphite wounded gasket is used for Class600 check valve,and joint gasket is also optional for Class 600 check valve,Ring joint gasket is used for Class900 check valve,Pressurizedseal design is used for Class 1500-Class2500 check valves.
The Features of Check valve
Bolted Bonnet; Swing and lift disc; Metallic seating surfaces.
Body and bonnet connection
The body and bonnet of Class 1500-Class900 check valves are usually with studs and nuts.And the body and bonnet of Class 1500-Class2500 check valves are usually of pressurized seal design.
For carbon steel check valve ,the seat is usually forged steel .The sealing surface of the seat is spray welded with hard alloy specified by the customer.Renewable threaded seat is used for NPS≤10 Check valves,and welded on seat can be also optional if being requested by the customer,Welded on seat is used for NPS≤12 Carbon steel gate valves.For Stainless steel check valve,integral seat is usually adopted,or to weld hard alloy directly in tegrally.Threaded or welded on seat is also optional for stainless steel check valve if being requested by the customer.
Structure of Cast steel Swing Type check valve
Large-caliber check valves are provided with lifting rings for The convenience of hoisting.
Bolted bonnet,and the type of middle flange gasket may be different according to pressure class,Class600 check valve may adopt pressure self-tightening seal structure.
Disc stop device to prevent disc from being opened too high.Thus causing failure to be closed down.
Solid pin is precisely installed and provided with high intensity to ensure operational performance and service life of valve.
Rocker arm is given enough strength .Upon being closed down it has enough freedom for the closed own of valve disc.
Valve disc is given enough strength and rigidity.Disc sealing surface may be builtup welded with metal material or inlaid with nonmetal material responding to users requests.