Patent ID: 8708342

Claim:
A pneumatically controlled dual mode face seal having a first mode and a second mode, the face seal comprising: a first, flat plate having a first face and a second face, and having at least one groove in the first face, and there is a first hole through the first plate from its second face to the at least one groove in its first face, and there is a second hole through the first plate from its second face to the at least one groove in its first face; a second, flat plate having a first face and a second face; wherein in the first mode of the dual modes the first face of the first plate touches the first face of the second plate to create a high friction between the first and second flat plates that inhibits movement of the first plate and the second plate with respect to each other and creates a gas and liquid tight seal between the first plate and second plate, wherein in the second mode of the dual modes the first face of the first plate does not touch the first face of the second plate and the first flat plate and the second flat plate have no friction with respect to each other that inhibits movement of the first plate and the second plate with respect to each other, wherein to change the first and second plates from the first mode to the second mode gas at a first pressure is applied via the first hole to the at least one groove in the first face of the first plate to separate the first plate and second plate and create a gas bearing there between that permits the first and second plates to be easily moved with respect to each other, and wherein after the first plate and second plate are separated, gas at a second pressure that is lower than the first pressure is applied via the second hole to the at least one groove in the first face of the first plate to maintain the face seal in the second mode, and when it is desired to return the first and second flat plates to the first mode where they touch each other and create a gas and liquid tight seal the gas at the second pressure is terminated.