Pressure activated emergency/temporary seal

Abstract

A pressurizable seal assembly provides a temporary seal which allows continued operation of a device, for example a pump, when the primary seal is removed for repair or replacement. The seal assembly includes a seal housing having a selectively pressurizable annular chamber with an open inner circumference surround the shaft of the device. An annular seal member is disposed in the annular chamber at the inner circumference thereof, and is actuable by pressure in the chamber to selectively sealingly engage the shaft. When the rotary shaft device has a single primary seal, the pressurizable seal may be provided between the stationary housing and the primary seal. When the primary seal of the rotary shaft device is a tandem seal, the pressurizable seal assembly may be disposed between the first and second primary seals of the tandem seal. The seal housing may be two-piece construction to facilitate its installation on and removal from the rotary shaft. In order to maintain the chamber at a predetermined pressure, a fitting may be provided which may be adapted to be attached to shop air pressure. In an alternative embodiment, an accumulator may be provided to maintain relatively constant chamber pressure. When the seal assembly is provided in combination with the tandem seal, the seal housing may include a receiving portion that forms a stationary sealing surface for one seal member of the tandem seal.