Patent ID: 7748923

Claim:
A gap-forming assembly for a non-positive displacement machine, said assembly comprising: an inner bush for mounting on a shaft of the non-positive displacement machine; said inner bush having an outer periphery provided with a first annular recess, said first annular recess having circularly annular walls and a bottom surface; a resilient ring received in said first recess such that the end faces of the ring are partially surrounded by the circularly annular walls of said first recess and a remaining part of the end faces of said ring extend beyond the circularly annular walls of said first recess; an outer bush surrounding said inner bush, said outer bush being adapted to be received in a rotationally fixed and non-displaceable manner in a housing of the non-positive displacement machine, and said inner bush being rotatable relative to said outer bush; said outer bush having an inner periphery provided with a second annular recess having at least one circularly annular wall axially aligned with a corresponding circularly annular wall of the first recess; said second annular recess enclosing the remaining part of the end faces of the ring which extend beyond the circularly annular walls of said first recess such that the ring is surrounded on all sides; wherein: one end of said second annular recess is defined by a tubular holding part which is inserted into and detachably connected to said outer bush; said ring is held in place by frictional contact with said outer bush, and said ring is constructed such that in the non-positive displacement machine, said ring during operation of said non-positive displacement machine forms an axial gap with each of the respective circularly annular walls of the first recess and forms a radial gap with the bottom surface of said first recess such that a gap passageway for limited passage of a flowing medium is formed by said axial gaps and said radial gap.