Bushing assembly and positive displacement rotary pump comprising said bushing assembly

A bushing assembly for a positive displacement rotary pump, arranged to be inserted into an internal cavity of a positive displacement rotary pump, axially floating therewithin, and to support the ends of a pair of shafts bearing the rotors of said positive displacement rotary pump;

• said bushing assembly comprising an inner face, facing, while in use, the rotors;
• an opposed outer face;
• wherein, while in use, the bushing assembly is free to axially slide within the internal cavity due to fluid pressures acting on the inner and external faces;
• the bushing assembly further comprising:
• a lateral surface which connects the two inner and outer faces, said lateral surface being arranged to be coupled within the internal cavity with a first portion facing a suction side and a second portion facing a discharge side;
• at least one compensation tank on the first portion of said lateral surface, in a position closer to the inner face than to the outer face;
• and at least one bleed channel which connects said at least one compensation tank to the second portion of the lateral surface;
• wherein the at least one compensation tank is laterally closed on both sides of the inner face and the outer face of the bushing assembly, wherein the at least one compensation tank does not open on the inner face nor on the external face of the bushing assembly.