Self-priming centrifugal pump assembly with multifunctional sealing system

A self-priming centrifugal pump assembly (1) with a multifunctional sealing system (20),

• wherein the pump (1) comprises:
• a housing (2) having a downstream wet area (8) contacted by a working fluid and an upstream dry area (9) not contacted by the working fluid and equipped with bearings (10′, 10″) for supporting a drive shaft (15), a volute pressure chamber (12) located in said downstream area (8) to accommodate a vane impeller (14) which is designed to be keyed to said shaft (15),
• wherein the sealing system (20) comprises:
• a tubular spacer (21) mounted to the shaft (15) and configured to be attached thereto proximate to the vane impeller (14);
• a mechanical seal (22) mounted to said tubular spacer (21);
• a first lip seal (23);
• a locking ring (30) for attaching said mechanical seal (22) to said housing (2), and
• wherein said pressure chamber (12) has a suction port (13) with an inner diameter larger than an inner diameter of the impeller (14) and a front closing flange (16) with an inner diameter smaller than the inner diameter of the impeller (14), said locking ring (30) being designed to be fastened to said housing (2) by removable fastening means (36) that can be accessed through the suction port (13) of the pump (1) after removal of the front closing flange (16), so that the impeller (14), said mechanical seal (22), and said lip seal (23) can be removed and replaced or serviced without disassembling the pump (1) and without accessing the bearings (10′, 10″) of said upstream dry area (9),
• wherein said locking ring (30) has a radial portion (32) configured to be accommodated in a compartment (35) of an intermediate housing (11) of the pump housing (2), a plurality of holes being provided receive bolts defining said removable fastening means (36),
• wherein said mechanical seal (22) and said first lip seal (23) are both attached to said tubular spacer (21) to define a unitary cartridge assembly (40), which is integrally removable from the shaft (15) when one or more components of the unitary cartridge assembly are being disassembled and replaced, and
• wherein said locking ring (30) has a tubular portion (31) with a second annular recess (43) to accommodate and stably attach said first lip seal (23) proximate to an axial end of said tubular portion (31) distal from the locking ring (14).