A SEAL FOR A PUMP, AND A PUMP COMPRISING THE SEAL

摘要

A pump (1) for pumping a slurry comprises a pump housing (2) defining a pumping chamber (5) with an impeller (6) located therein for pumping the slurry from an axial inlet port (7) to a radial outlet port (8). The impeller (6) is carried on a pump shaft (10) which is in turn rotatably carried in a shaft carrier sleeve (18) in a carrier housing (12) which also carries the pump housing (2). The shaft carrier sleeve (18) and the pump shaft (10) are axially adjustable in the direction of the arrows A and B for adjusting an axial clearance gap (25) between the impeller (6) and the pump housing (2). A shaft seal (9) for sealing the pumping chamber (5) comprises a packed gland seal (42) and a rotating sealing ring (38) and a stationary sealing ring (39). A lubricating fluid cavity (40) is located between the packed gland seal (42) and the rotating and stationary sealing rings (38, 39) for lubricating axially facing rotating and stationary sealing surfaces (52, 58). The stationary sealing ring (39) is engageable with a shoulder (61) on the pump shaft (10) for urging the stationary sealing ring (39) along with the pump shaft (10) as the axial clearance gap (25) is being closed so that when the axial clearance gap (25) is being opened to the desired clearance width (x) the rotating and stationary sealing surfaces (52, 58) are brought into sealing engagement with each other.