Fluid transfer pump with shaft seal structure

Abstract

An improved sealing apparatus for gear transfer pump of the type that includes a gear driven by a drive shaft connected to a drive source. The drive shaft extends through a backhead which includes a seal system for inhibiting fluid leakage between the drive shaft and the backhead. The seal system includes a tubular insert held at one end by a support element threadedly received in an end bore of the backhead and structure defined by the backhead which engages another portion of the insert and includes a secondary seal for inhibiting fluid leakage between the insert and the backhead. The insert includes structure for mounting at least a portion of the seal in predetermined alignment with the drive shaft. The drive shaft includes an abutment for locating a rotating portion of the seal for applications that include two-part seals. A seal cartridge is disclosed in which non-rotating and rotating portions of the seal form a single assembly that is installed as a unit into the backhead. During installation non-rotating portions of the seal cartridge are locked to the backhead whereas rotating portions of the seal are clamped to the drive shaft. The seal insert forms part of the seal cartridge and is connected to a seal support sleeve by a connecting member to form an assembly that is installed as unit. This sealing system also makes provision for tandem and double seals as well as means for quenching or flushing seals or seal portions.