GB2159589A

GB2159589A - Seal for shaft passing through a housing

Info

Publication number: GB2159589A
Application number: GB08513643A
Authority: GB
Inventors: Brian Glover
Original assignee: GRUNDY
Current assignee: GRUNDY
Priority date: 1984-06-01
Filing date: 1985-05-30
Publication date: 1985-12-04
Also published as: GB8513643D0; GB2159589B

Abstract

A pump unit has a drive shaft (4) rotatably mounted in a bearing assembly (5) located in a housing (6) integral with casing (1). The shaft (4) has a lateral flange (7) with a machined inwardly facing surface (8) which engages a surface (9) of a sealing ring (10) provided around a boss (11) of the shaft. The surfaces (8, 9) form a sliding seal. The ring (10) is of carbon material and lies around the boss (11) of the shaft, the ring has a tapered shouldered recess (12) which receives a rubber O-ring (13). The O-ring (13) forms a seal between the bearing ring (10) and housing (1). A plate (14) serves to trap the O-ring (13) and applies a longitudinal compressive force to force same into sealing engagement with the sealing ring (7), and thus to press the ring (10) against the flange (7). A loading force is therefore applied between surfaces (8, 9) to effect a seal. <IMAGE>

Description

SPECIFICATION Sealing shafts This invention relates to sealing shafts and is particularly concerned with the sealing of rotating shafts in pumps. With small pump units used for beverage dispensing, as example, it is required to seal the impeller shaft where it passes through the pump housing to connect with a driving means. In known units this seal is achieved by using spring force to maintain a rotating sealing member of carbon material in contact with a bearing surface on the pump housing. The spring occupies space and does not always provide an efficient seal.

It is an object of this invention to provide a seal for a rotating shaft which occupies little space and which affords an improved sealing action as well as being of simple construction.

According to this invention there is provided a sealing means for shaft rotatable in a housing such as a shaft driving a pump rotor mounted in a pump casing with the shaft passing through a wall of the casing, wherein the shaft has a lateral flange with an inwardly facing surface in face-to-face abutment with one side surface of a sealing ring located around the shaft and positioned within a cylindrical recess of the housing, the other side of the sealing ring having a shouldered recess in which a resilient O-ring is located, the O-ring being pressed against the sealing ring to form a seal between the ring and housing wall and to provide a loading force to maintain the one side surface of the sealing ring and the inner surface of the flange in sealing engagement.

Further and preferred features of this invention are shown by way of example in the accompanying drawing showing a cross-section through a pump unit embodying a shaft sealing means according to this invention.

Referring to the drawing, this shows a pump unit primarily for beverages having a pump casing 1 containing a pump rotor 2 engaging a crank pin 3 mounted eccentrically with respect to the axis of a drive shaft 4. The drive shaft is rotatably mounted in a bearing assembly 5 located in a housing 6 integral with casing 1. The shaft 4 has a lateral flange 7 with a machined inwardly facing surface 8 which engages a surface 9 of a sealing ring 10 provided around a boss 11 of the shaft.

The surfaces 8 and 9 form a sliding seal. The ring 10 is of carbon material and lies around the boss 11 of the shaft, the ring has a tapered shouldered recess 1 2 which receives a rubber O-ring 13. The O-ring 13 forms a seal between the bearing ring 10 and housing 1. A plate 14 serves to trap the O-ring 1 3 and applies a longitudinal compressive force to force same into sealing engagement with the sealing ring 7, and thus to press ring 10 against flange 7. A loading force is therefore applied between surfaces 8, 9 to effect a seal.

This arrangement provides a compact construction for the shaft seal with the O-ring providing an appropriate seal against the housing and in addition applying precompression to ensure that the surfaces 8 of the flange and 9 of the carbon sealing ring are held always in sealing engagement.

An important feature in this arrangement is the tapered recess 1 2 which houses O-ring 1 3. This ensures that a progressive force is present to maintain ring 10 in contact with flange 7. The arrangement offers a loading characteristic between surfaces 8 and 9 which is similar to that which would be provided by a spring.

1. A sealing means for a shaft rotatable in a housing such as a shaft driving a pump rotor mounted in a pump casing with the shaft passing through a wall of the casing, wherein the shaft has a lateral flange with an inwardly facing surface in face-to-face abutment with one side surface of a sealing ring located around the shaft and positioned within a cylindrical recess of the housing, the other side of the sealing ring having a shouldered recess in which a resilient O-ring is located, the O-ring being pressed against the sealing ring to form a seal between the ring and housing wall and to provide a loading force to maintain the one side surface of the sealing ring and the inner surface of the flange in sealing engagement.

2. A sealing means according to Claim 1, wherein the sealing ring is of a carbon material.

3. A sealing means according to Claim 1 or 2, wherein the sealing ring has a boss on the inwardly facing surface, the sealing ring seating over the boss.

4. A sealing means according to any preceding claim, wherein the O-ring is pressed against the sealing ring by a plate.

5. A sealing means according to any preceding claim, wherein the recess is tapered.

6. A sealing means according to any preceding claim, wherein the inner surface of the shouldered recess is tapered.

7. A sealing means for a shaft rotatable in a housing and driving a pump rotor mounted in a pump casing with the shaft passing through a wall of the casing, the internal pump casing being sealed by face to face sliding contact established between a rotating flanged part of the shaft and a static sealing ring, a seal being established between the periphery of the ring and housing wall, the seal comprising an O-ring subject to compressive force along the shaft axis to load the sliding sealing surfaces of the flange and sealing ring.

8. A sealing means according to Claim 7, wherein the O-ring seals within a tapered recess.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Sealing shafts This invention relates to sealing shafts and is particularly concerned with the sealing of rotating shafts in pumps. With small pump units used for beverage dispensing, as example, it is required to seal the impeller shaft where it passes through the pump housing to connect with a driving means. In known units this seal is achieved by using spring force to maintain a rotating sealing member of carbon material in contact with a bearing surface on the pump housing. The spring occupies space and does not always provide an efficient seal. It is an object of this invention to provide a seal for a rotating shaft which occupies little space and which affords an improved sealing action as well as being of simple construction. According to this invention there is provided a sealing means for shaft rotatable in a housing such as a shaft driving a pump rotor mounted in a pump casing with the shaft passing through a wall of the casing, wherein the shaft has a lateral flange with an inwardly facing surface in face-to-face abutment with one side surface of a sealing ring located around the shaft and positioned within a cylindrical recess of the housing, the other side of the sealing ring having a shouldered recess in which a resilient O-ring is located, the O-ring being pressed against the sealing ring to form a seal between the ring and housing wall and to provide a loading force to maintain the one side surface of the sealing ring and the inner surface of the flange in sealing engagement. Further and preferred features of this invention are shown by way of example in the accompanying drawing showing a cross-section through a pump unit embodying a shaft sealing means according to this invention. Referring to the drawing, this shows a pump unit primarily for beverages having a pump casing 1 containing a pump rotor 2 engaging a crank pin 3 mounted eccentrically with respect to the axis of a drive shaft 4. The drive shaft is rotatably mounted in a bearing assembly 5 located in a housing 6 integral with casing 1. The shaft 4 has a lateral flange 7 with a machined inwardly facing surface 8 which engages a surface 9 of a sealing ring 10 provided around a boss 11 of the shaft. The surfaces 8 and 9 form a sliding seal. The ring 10 is of carbon material and lies around the boss 11 of the shaft, the ring has a tapered shouldered recess 1 2 which receives a rubber O-ring 13. The O-ring 13 forms a seal between the bearing ring 10 and housing 1. A plate 14 serves to trap the O-ring 1 3 and applies a longitudinal compressive force to force same into sealing engagement with the sealing ring 7, and thus to press ring 10 against flange 7. A loading force is therefore applied between surfaces 8, 9 to effect a seal. This arrangement provides a compact construction for the shaft seal with the O-ring providing an appropriate seal against the housing and in addition applying precompression to ensure that the surfaces 8 of the flange and 9 of the carbon sealing ring are held always in sealing engagement. An important feature in this arrangement is the tapered recess 1 2 which houses O-ring 1 3. This ensures that a progressive force is present to maintain ring 10 in contact with flange 7. The arrangement offers a loading characteristic between surfaces 8 and 9 which is similar to that which would be provided by a spring. CLAIMS

9. A sealing means for a shaft as described herein and shown in the drawing.

10. A pump for fluids as described herein and shown in the drawing.