GB2519286A

GB2519286A - Single face bearing protector

Info

Publication number: GB2519286A
Application number: GB1316891.9A
Authority: GB
Inventors: Thomas Broadbent
Original assignee: AES Engineering Ltd
Current assignee: AES Engineering Ltd
Priority date: 2013-09-23
Filing date: 2013-09-23
Publication date: 2015-04-22
Anticipated expiration: 2033-09-23
Also published as: GB2519286B; GB201316891D0

Abstract

A single face bearing protector is provided. The protector takes the form of a contacting seal device for providing a mechanical seal between an equipment housing 2 and a rotatable shaft 3 comprises a stator 4 sealable to the housing 2 by a first o-ring 5 and a rotor 10, 12 sealable to the shaft by second and third o-rings 13, 14. The stator 4 and rotor 3 each have contact faces 9, 10 which are urged together by springs 11. The third o-ring 14 is located in an annular groove having an angled profile 16 and the seal has a unitised constriction which limits axial movement of the rotor 3.

Description

Single Face Bearing Protector

Field of Invention

The invention relates to a contacting face seal for use with rotating equipment where a lubricating fluid is required to be sealed into a chamber.

Background to Invention

Bearing protectors are commonly used to stop ingress of fluids or solids from entering a bearing chamber. They are also simultaneously used to stop egress of the lubricating fluids from the bearing chamber. Essentially the aim of a bearing protector is to therefore prevent the premature failure of the bearings.

Commonly there exist two types/categories of bearing protector: labyrinth seals and mechanical seal bearing protectors. Labyrinth seals typically have a complex outer profile which is located adjacent and in close radial and axial proximity to a complex inner profile of the stationary component. Together these complex profiles provide a tortuous path preventing the passage of materials or fluids through the seal. Due to the non contacting characteristics of the labyrinth design its use in flooded or pressurised environments is limited.

Mechanical seal bearing protectors are therefore commonly utilised in these applications as contacting faces ensure that limited or no fluid is able to pass through the seal. The face pressure between the stationary and rotating faces, which ensures contact between the faces is maintained, is commonly produced through the use of magnets.

The invention overcomes a number of problems that currently exist with the AESSEAL mechanical seal bearing protector design, named the Magtecta. These problems include high operating temperatures in marginal lubrication applications due to dual faces urged together through the use of magnets increasing the operating temperatures of the seal.

Secondly due to the layout of the design one of the faces contains an 0-ring that contacts the shaft. This causes large lead times and increased costs for customer specific designs.

Statements of Invention

The invention relates to a contacting seal device for providing a mechanically seal between equipment housing and an equipment shaft limiting the ingress or egress of fluids or particles into the bearing chamber. The invention, with reference to the accompanying drawings, preferably comprises: * a stator sealable to the equipment housing by a first toroidal member, * a first rotor sealable to the equipment shaft by a second and third toroidal sealing member, * said stator and rotor each having contact faces, * said contact faces are urged toward one another via one or more springs, * said tertiary toroidal sealing member residing in an annulus groove with angular profile, * said seal having unitised construction which ensures said rotor has restricted axial movement.

Preferably said angular profile of the annulus groove in which the tertiary toroidal sealing member resides is proportioned in such a way as to substantially increase compression of said sealing member as said rotor is moved axially from said seal device, and more preferably the angular profile of said annulus groove is proportioned so that it is 33% the width of the groove and has a gradient of 3Q°.

Preferably said unitisation of said seal; wherein unitisation refers to the device maintaining one assembly in its non fitted state; is achieved by a combination of components which extend from said seal housing so that said rotor contacts said components when moved axially.

Said unitisation more preferably provides the required face pressure and is factory set and maintained by a toroidal member positioned between said rotor and said seal housing.

Said combination of components that extend from said seal housing more preferably comprises a ring of material with a low coefficient of friction and preferably a circlip that provides rigidity to said components.

Said combination of components more preferably comprises a ring of material with a low coefficient of friction in closest proximity to said rotary components and said circlip located on the side of the ring that is at furthest proximity to the rotary components.

A device according to any of the preceding statements; wherein said components which restrict axial movement of said rotor more preferably are manufactured from a material with limited frictional coefficient.

A device according to any of the preceding statements; wherein said stator more preferably has a passage to allow fluid to be expelled from said device.

A device according to any of the preceding statements; wherein said stator and rotor are more preferably manufactured from metallic materials.

Brief Description of Drawings

Figure 1 shows a cross-section through the preferred embodiment of the invention.

Figure 2 shows a cross-section perpendicular to Figure 1 through the preferred embodiment of the invention.

Detailed Description

According to the present invention a bearing protector (1) that forms a seal between a stationary component such as a bearing chamber housing (2) and a rotating component such as a shaft (3). Said bearing protector comprises a combination of stationary components and a combination of rotary components.

The stationary components comprise the seal housing (4) of annular profile which is fitted into said bearing chamber housing (2) with a degree of interference to detachably attach said seal (1) to said housing (2). An 0-ring (5) located in an annulus groove (6) on the interfering portion of the seal housing (4) to provide a hydraulic seal between said seal housing (4) and said bearing chamber (2). A second sealing 0-ring (7) is positioned in a secondary annulus groove (8) located on the inner diameter of said seal housing (4). Said 0-ring (7) provides a hydraulic seal between said seal housing (4) and said stationary face (9). Said stationary face (9) is sized to provide the largest radial distance between itself and said rotating shaft (3). The largest surface of said stationary face (9) is lapped to within 1-2 light bands to provide a suitably flat surface for a rotating face (10) with a surface of equal flatness to rotate against. Said rotating face (10) is manufactured from a softer material than said stationary face (9) to allow it to wear in preference to said stationary face (9) aiding mechanical sealing performance. Said rotating face (10) is urged towards said stationary face (9) by a plurality of springs (11) which have been compressed to such a degree that provides a predetermined pressure between said stationary face (9) and rotary face (10).

Said springs (11) are located in a plurality of holes in a secondary rotary component (12).

Said secondary rotary component (12) is in contact via two 0-rings (13 & 14) of differing sizes to said shaft (3). Said primary 0-ring (13) maintains a hydraulic seal to said shaft (3).

Said secondary 0-ring (14) is located in an annulus groove (15) with an angled portion (16) which causes the diameter of said groove to reduce as said rotating component (12) is moved axially away from said bearing chamber housing (2) thus increasing squeeze from said 0-ring (12) to said shaft (3). Said increased squeeze increases the resistance to axial movement from said rotary component (12). Said rotary component (12) also comprises a plurality of pins (17) which protrude from said rotary component (12) into slots (18) circuniferentially located around said rotary face (10) thus providing drive to said rotary face (10) from said rotary component (12). An 0-ring (19) is also located between said rotary face (10) and said rotary component (12) providing a hydraulic seal between said components.

Unitisation of said bearing protector (1) is achieved via a disc of low frictional coefficient (20) and a circlip (21). Said disc (20) and circlip (21) are located in an annulus groove (22) in said seal housing (4) and once filled have an inner diameter that is adequately small to overlap said rotary component (12) thus ensuring said rotary component (12) cannot be removed from said bearing protector (1). Over compression of said springs (11) is not possible through the location of an 0-ring (23) between said rotary component (12) and said seal housing (4). The material of said 0-ring (23) and said disc (20) are of low frictional coefficient and so limiting heat generation should contact between them and said rotating component (12) exist. Said 0-ring (23) also ensures that contact between said rotary component (12) and said stationary seal housing (4) is not possible.

In a secondary embodiment of said invention one of said 0-rings (13 &14) is made from a conductive material thus allowing electrical charge to flow from said bearing chamber housing (2) through said seal (1) to said shaft (3) thereby stopping electrical discharge through the bearings.

Claims

Claims 1. A contacting seal device for providing a mechanically seal between equipment housing and an equipment shaft comprising: * a stator sealable to the equipment housing by a first toroidal member, * a first rotor sealable to the equipment shaft by a second and third toroidal sealing member, * said stator and rotor each having contact faces, * said contact faces are urged toward one another via one or more springs, * said tertiary toroidal sealing member residing in an annulus groove with angular profile, * said seal having unitised construction which ensures said rotor has restricted axial movement.
2. A device according to Claim 1, wherein the angular profile of the annulus groove in which the tertiary toroidal sealing member resides is proportioned in such a way as to substantially increase compression of said sealing member as said rotor is moved axially from said seal device.
3. A device according to Claim 2, wherein the angular profile of said annulus groove is proportioned so that it is 33% the width of the groove and has a gradient of 300.
4. A device according to Claim 1 or Claim 2, wherein said unitisation of said seal is achieved by a combination of components which extend from said seal housing so that said rotor contacts said components when moved axially.
5. A device according to Claim 3, wherein the required face pressure is factory set and maintained by a toroidal member positioned between said rotor and said seal housing.
6. A device according to Claim 3, wherein said combination of components that extend from said seal housing preferably comprises a ring of material with a low coefficient of friction and preferably a circlip that provides rigidity to said components.
7. A combination of components according to Claim 6 with the ring of material with a low coefficient of friction in closest proximity to said rotary components and said circlip located on the side of the ring that is at furthest proximity to the rotary components.
8. A device according to any of the preceding claims, wherein said components which restrict axial movement of said rotor are manufactured from a material with limited frictional coefficient.
9. A device according to any of the preceding claims, wherein said second or third toroidal sealing member is manufactured from a conductive material composite to allow electric charge to flow through said seal.
10. A device according to any of the preceding claims, wherein said stator has a passage to allow fluid to be expelled from said device.
11. A device according to any of the preceding claims, wherein said stator and rotor are manufactured from metallic materials.
12. A device according to Claim 1 and substantially as herein described.
13. A contacting seal device substantially as described herein with reference to the accompanying drawings.Claims Amendments to the claims has been made as follows 1. A contacting seal device for providing a mechanical seal between an equipment housing and an equipment shaft comprising: * a stator sealable to the equipment housing by a first toroidal member, * a rotor sealable to the equipment shaft by a second and a third toroidal sealing member, * said stator and rotor each having contact faces, * said contact faces being urged towards one another via one or more springs, * said third toroidal sealing member residing in an annular groove having an angled portion which increases squeeze on said sealing member as said rotor moves axially away from said stator.2. A device according to Claim 1, wherein the angular profile of said annular groove is proportioned so that it is 33% the width of the groove and has a gradient of 300.3. A device according to Claim 1 or Claim 2, wherein the device is provided with means LC*) for preventing separation of the stator and rotor when the device is not fitted to a shaft. (44. A device according to Claim 3, wherein the required face pressure is factory set and 0) maintained by a toroidal member positioned between said rotor and said seal housing.5. A device according to Claim 3 or Claim 4, wherein the separation preventing means comprise a ring of material with a low coefficient of friction and preferably a circlip that provides rigidity to said components.6. A device according to Claim 5 wherein the ring of material with a low coefficient of friction is closer to the contact faces than the circlip.7. A device according to any of the preceding claims, wherein at least one of said second or third toroidal sealing members is manufactured from a conductive material composite to allow electric charge to flow through said seal.8. A device according to any of the preceding claims, wherein said stator has a passage to allow fluid to be expelled from said device.9. A device according to any of the preceding claims, wherein said stator and rotor are manufactured from metallic materials.10. A device according to Claim 1 and substantially as herein described.11. A contacting seal device substantially as described herein with reference to the accompanying drawings. IC) (4 a) r