Patent ID: 6375414
Filing Date: 2002-04-23
Classification: F04D,F16J

Abstract:
A shaft seal (9) for a pump (1) of the type comprising a pump housing (2) defining a fluid pumping chamber (5), an impeller (6) located in the pumping chamber (5), a pump shaft (10) carrying the impeller (6) for rotating the impeller (6) in the pumping chamber (5) for pumping fluid through the pumping chamber (5), and a shaft accommodating bore (11) extending through the pump housing (2) into the pumping chamber (5) for accommodating the pump shaft (10) into the pumping chamber (5), the pump shaft (10) being axially movable in the shaft bore (11) for adjusting an axial clearance gap (25) between a face (26) of the impeller (6) and an adjacent face (2) of the pump housing (2) in the pumping chamber (5), the shaft seal (9) seal (9) comprising a stationary sealing ring (39) for mounting in the shaft bore (11) and having a stationary sealing surface (58), a rotating sealing ring (38) for mounting on the pump shaft (10) and having a rotating surface (52) for cooperating with the stationary sealing surface (58) for forming seal form the pumping chamber (5) between the pump shaft (10) and the pump housing (2) in the shaft bore (11), characterised in that the stationary and rotating sealing surfaces (58, 52) face in respective generally axial directions opposite to each other, and one of the stationary sealing ring (39) and the rotating sealing ring (38) is axially movable relative to the corresponding one of the pump housing (2) and the pump shaft (10), and a means (60, 63) is provided for axially moving the moveable one of the stationary sealing ring (39) and the rotating sealing ring (38) with the other of the stationary and the rotating sealing rings (39, 38) during axial movement of the pump shaft (10) and the pump housing (2) relative to each other in a direction for closing the axial clearance gap (25) in the pumping chamber (5) between the impeller (6) and the pump housing (2), so that on the relative axial movement of the pump shaft (10) and the pump housing (2) for opening the axial clearance gap (25) to the desired gap width (x), the respective stationary and rotating sealing surfaces (58, 52) are brought into sealing relationship with each other.