Check Valves BoTeli valves are available in three bonnet designs. The first design is the Bolted Bonnet, With male-female joint, spiral wound gasket, made in F304L/graphite, Ring joint gasket are also available on request. The second design is the welded bonnet ,with a threaded and seal welded joint. On request a full penetration strength welded joint is available. The trird 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. Gate Valve Design Construction and Specifications BoTeLi check valves conform to MSS-SP-118 and ASME B 16.34. Each are tested according to API598, and marking is per MSS SP-25. Construction is as follows: Full Port or Convetional PortPiston CheckBall checkSwing checkSpring available on requestBolted bonnet with spiral-wound gasket, threaded and seal welded bonnet or threaded and pressure seal bonnetSocket weld ends to ASME B16.11Screwed Ends(NPT) to ANSI/ASME B1.20.1