# US 4,399,997 A · Sealing bush unit for sealing reciprocating machine parts > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,399,997 A - Document ID: US4399997A - Status: Granted - Kind: A - Application number: 06/381,513 - Filed: 1982-05-24 - Granted: 1983-08-23 - Earliest claimed: 1981-05-29 - Inventors: Erich Broken - Web page: https://patentgrep.com/patent/US4399997A ## CPC - F16J 15/56: Other sealings for reciprocating rods - F04B 53/162: {Adaptations of cylinders} - F16J 15/441: {with floating ring} - F16J: PISTONS {(specially adapted for dampers F16F9/32)}; CYLINDERS; SEALINGS - F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F) ## Abstract A sealing bush unit for sealing a reciprocating machine part has an annular bush with an inner diameter exceeding an outer diameter of the reciprocating pump to form a radial gap therebetween, a radially outer surface arranged so that a working pressure acts upon the same and the bush radially displaces towards the reciprocating part, one flat end face facing toward a suction zone and providing an abutment for the sealing bush, and another end face facing toward a pressure zone, wherein a pressing ring is arranged adjacent to the other end face of the bush with axial play relative to a machine housing. ## Claims ### Claim 1 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 2 (depends on 1) 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 3 (depends on 1) 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 4 (depends on 1) A sealing bush unit as defined in claim 1, wherein said pressing ring has a radially outer surface having a spherical shape. ### Claim 5 (depends on 1) 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 6 (depends on 1) 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 7 (depends on 5) 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 8 (depends on 7) A sealing bush unit as defined in claim 7, wherein said sealing member is formed as a high-pressure sealing member. ### Claim 9 (depends on 1) 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 10 (depends on 1) 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 11 (depends on 1) 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 12 (depends on 11) 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 13 (depends on 1) 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 14 (depends on 1) 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 15 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.