PUMP WITH MECHANICAL SEAL ASSEMBLY

摘要

A sliding vane, positive displacement pump is provided which includes a dual mechanical seal that protects against leakage from a pump chamber while also reducing slip across rotor end faces. The dual mechanical seal may be formed as a cartridge seal that is readily demountable from the pump for replacement and service, and is retrofittable to existing pumps to improve the performance thereof. The pump may integrally include a dual mechanical seal, or the mechanical seal assembly may be provided for use by itself or in combination with a replaceable head ring that can be installed on existing pumps for repair thereof or for a retrofit upgrade of such existing pump.

主权项

1. A pump, comprising:
a pumping assembly comprising a casing which defines a pump chamber having at least one open end, a rotatable shaft entering said pump chamber through said open end, and a rotor within said pump chamber having a rotor end face which faces said open end, said rotor being rotatably driven by said shaft to effect pumping of a process fluid, said pump assembly further including at least one head ring mounted to said casing to partially enclose said open end of said pump chamber, said head ring including a head bore which receives said shaft therethrough, and said head bore being defined by an inner bore surface spaced radially outwardly of an outer shaft surface to define a seal pocket which opens towards said rotor end face; and a mechanical seal assembly comprising: a rotatable sealing ring which is rotatably mounted on said shaft for rotation therewith, said rotatable sealing ring being disposed within said seal pocket of said head bore with an inboard first ring surface disposed in axial facing contact with said rotor end face, said rotatable sealing ring having an opposite, outboard second ring surface facing away from said rotor and defining at least a first rotating sealing face; a seal housing mounted to said pumping assembly; at least a first stationary sealing ring which is non-rotatably mounted to said seal housing and defines a first stationary sealing face disposed in opposed, sealing engagement with said first rotating sealing face, said first rotating and stationary sealing faces defining a first sealing region which sealingly separates first and second fluid chambers respectively containing a first fluid and a pressurized second fluid at a pressure greater than said first fluid, said pressurized second fluid acting on said rotating sealing ring to axially bias said rotating sealing ring into contact with said rotor end face to reduce slip of said process fluid across said rotor end face.