Patent ID: 8101420

Claim:
A purgeable fluid sealing valve apparatus comprising: (a) a valve housing defining a valve interior region and having a at least four separate valve ports into or out of the valve interior region wherein: a first pair of the valve ports provides a valve main fluid inlet and a valve main fluid outlet for flowing a liquid into, through and out of the valve interior region when the valve is in a first operating configuration; and, a second pair of the valve ports provides a valve purge gas inlet and a valve purge gas outlet for flowing a purge gas into, through and out of the valve interior region at least when the valve is in a second operating configuration; and, (b) a moveable plunger element which can be moved between an advanced position and a retracted position, a front portion of the valve plunger element which is located in the valve interior region comprising a plunger seal member sized and shaped to be seated on and to plug the valve main fluid outlet or the valve main fluid inlet when the valve is in the second operating configuration in which the valve plunger element is in the advanced position, and to unseal the valve main fluid outlet or the valve main fluid inlet when the valve is in the first operating configuration in which the plunger element is in the retracted position.