will recognize that cartridge 400 also may include optional side plates not shown affixed between plates 406 and 410 to fully enclose the valve assembly within cartridge 400 extending along the fluid pathway 402 from hemi wedge 50 in the direction of outlet retainer 410 is a seat assembly comprising a set of elements 412 420 that aid in providing a high pressure seal when the hemi wedge 50 is in the closed position in physical contact with the hemi wedge 50 is a seat 414 which provides the seal in the closed position while it is preferred that seat 414 be formed of metal to provide a tight metal to metal seal other materials suitable for the intended operating environment e g o rings made of rubber or hard plastics such as polytetrafluoroethylene ptfe such as teflon u00ae might be used seat 414 is disposed in an appropriate groove on the inlet side of spacer 416 surrounding seat 414 is retaining ring 412 which helps maintain seat 414 in place preventing blow out of the seat during opening and closing of hemi wedge 50 on the opposite or outlet side of spacer 416 is a second groove for receiving another seal element 418 like seat 414 seal element 418 is an o ring which may be formed of any appropriate material e g rubber plastic such as ptfe or metal seal element 418 is maintained in place by retaining ring 420 when installing the cartridge 400 into housing.