check valves are available in Three bonnet designs.The first design is the Bolted Bonnet,with male-female joint,spiral wound gasket,made in F304/graphite.Ring joint gasket are also available on request.Thesecond desing is the welded bonnet,with a threaded and seal welded joint.On request a full penetration strengt welded joint is available .The third design is the pressure seal bonnet,with a threaded and pressure seal bonnet joint.The check valve are also available in three different design configurations. These are piston check,ball check,or swing check designs. Design Construction : Check valves conform to ASME B16.34 Each are tested according to API 589, and marking is per MSS SP-25. Design Construction: Full Port or Conventional Port Piston check Ball check Swing check Spring available on request Bolted bonnet with spiral wound gasket,threaded and Seal welded bonnet or threaded and pressure seal bonnet Socket weld ends to ASME B16.11 Screwed Ends(NPT) to ANSI/ASME B1.20.1 ?00LB ?00LB~1500LB ?00LB,900LB~1500LB ?00LB~2500LB ?00LB~2500LB