Sealing bush unit for sealing reciprocating machine parts

Claim 2

A sealing bush unit for sealing a reciprocating machine part, particularly a plunger of a fluid-displacing pump having a pump housing with suction and pressure sides, the sealing bush unit comprising an annular bush having an axis, a radially inner surface with an inner diameter exceeding an outer diameter of a plunger so as to form a radial gap therebetween, a radially outer surface arranged so that a working pressure acts upon said radially outer surface over a part of its axial length and thereby said bush radially displaces toward the plunger, and two end faces of which one end face faces toward a suction zone and the other end face faces toward a pressure zone, said one end face being flat and extending normal to said axis of said bush to provide axial abutment of the latter; and a pressing ring arranged adjacent to the other end face of said bush with an axial play relative to the pump housing.

Claim 3

A sealing ring unit as defined in claim 1, wherein said pressing ring has an inner diameter which is greater than said inner diameter of said inner surface of said bush.

Claim 4

A sealing bush unit as defined in claim 1; and further comprising a sealing member arranged between said pressing ring and the pump housing.

Claim 5

A sealing bush unit as defined in claim 1, wherein said pressing ring has a radially outer surface having a spherical shape.

Claim 6

A sealing bush unit as defined in claim 1, wherein said pressing ring has a radially outer surface provided with a seal-receiving recess.

Claim 7

A sealing bush unit as defined in claim 1, wherein the housing has a recess; and further comprising a sealing member arranged in said recess of said housing.

Claim 8

A sealing bush unit as defined in claim 5; and further comprising a sealing member arranged in said seal-receiving recess of said pressing ring.

Claim 9

A sealing bush unit as defined in claim 7, wherein said sealing member is formed as a high-pressure sealing member.

Claim 10

A sealing bush unit as defined in claim 1, wherein the housing has a further recess, said pressing ring being received in said further recess of said housing.

Claim 11

A sealing bush unit as defined in claim 1; and further comprising spring means arranged between said pressing ring and the housing in said axial play.

Claim 12

A sealing bush unit as defined in claim 1, wherein said one end face of said bush is formed as a flat face extending normal to said axis of said bush.

Claim 13

A sealing bush unit as defined in claim 11, wherein said one end face of said bush is arranged to directly abut against the housing.

Claim 14

A sealing bush unit as defined in claim 1, wherein said bush has an extension which extends through and axially beyond said pressing ring.

Claim 15

A sealing bush unit as defined in claim 1, wherein the housing has a part facing toward said one end face of said bush and having an annular recess and a passage communicating the latter with the suction zone.

Claim 16

A machine, particularly a fluid-displacing pump, comprising a pump housing with suction and pressure zones; a plunger reciprocating in said pump housing and having a predetermined outer diameter; an annular sealing bush having an axis, a radially inner surface with an inner diameter exceeding the outer diameter of a plunger so as to form a radial gap therebetween, a radially outer surface arranged so that a working pressure acts upon said radially outer surface over a part of its axial length and thereby said bush radially displaces toward said plunger, and two end faces of which one end face faces toward a suction zone and the other end face faces toward a pressure zone, said one end face being flat and extending normal to said axis of said bush to provide axial abutment of the latter; and a pressing ring arranged adjacent to the other end face of said bush with an axial play relative to said pump housing.

Claim 17

A machine, particularly a fluid-displacing pump, comprising a pump housing with suction and pressure zones; a plunger reciprocating in said pump housing and having a predetermined outer diameter; an annular sealing bush having an axis, a radially inner surface with an inner diameter exceeding the outer diameter of a plunger so as to form a radial gap therebetween, a radially outer surface arranged so that a working pressure acts upon said radially outer surface over a part of its axial length and thereby said bush radially displaces toward said plunger, and two end faces of which one end face faces toward a suction zone and the other end face faces toward a pressure zone, said one end face being flat and extending normal to said axis of said bush to provide axial abutment of the latter; and a pressing ring arranged adjacent to the other end face of said bush with an axial play relative to said pump housing.