GB2044862A

GB2044862A - Mechanical seal for preventing fluid leakage

Info

Publication number: GB2044862A
Application number: GB8008758A
Authority: GB
Original assignee: George Angus and Co Ltd
Current assignee: George Angus and Co Ltd
Priority date: 1979-03-16
Filing date: 1980-03-14
Publication date: 1980-10-22
Also published as: GB2044862B

Abstract

A mechanical seal for pumps and the like comprises a carbon face-sealing ring 3 adhesively secured and axially located by a shoulder in a metal housing ring 6 and resiliently loaded by a compression spring 5 to seal against a counterface ring 4, the carbon sealing ring and the counterface ring being respectively sealed in relatively rotatable parts by resilient O- ring backing seals 7, 8. <IMAGE>

Description

SPECIFICATION Mechanical seal for preventing fluid leakage This invention relates to mechanical seals for preventing fluid leakage and in particular socalled face-seals for preventing leakage along rotary shafts, in pumps for example.

The invention aims at the provision of a simple low-cost seal comprising a small number of parts which can easily be assembled and installed.

For the above purpose, the invention is applied to a mechanical face-seal comprising a face-sealing ring and a counterface ring, both of rigid material, with a coiled compression spring for loading the face-sealing ring axially into relatively rotatable face-sealing contact against the counterface ring, the face-sealing ring and counterface ring being provided with resiliently-deformable sealing rings, for static sealing respectively on a shaft and in a shafthousing, and the face-sealing ring being carried by a surrounding housing which in turn is carried by the coiled compression spring for mounting on a shaft. The spring acts as a drive spring for rotation of the seal with the shaft.

According to the invention, in a seal of the above kind, the face-sealing ring is adhesively secured in its housing in axial abutment against a shoulder in its housing and an inner face of the face-sealing ring together with an adjacent wall portion of its housing provide axial and surrounding circumferential location surfaces for a resiliently-deformable shaft-sealing ring.

Such securing of the face-sealing ring provides very simply for sealing of the facesealing ring in its housing, with effective prevention of relative rotation under face-drag in use, and also provides for location of the face-sealing ring by axial and circumferential abutment surfaces, when the seal is mounted on a shaft.

The invention also includes other advantageous features, for axial spring-loading of the shaft-sealing ring and for reducing the over-all diameter of the seal, which are included in the following description with reference to the accompanying drawing, wherein:- Figures 1 to 4 show half axial sections of four embodiments of seals according to the invention, and Figure 5 shows a perspective view of a sealing ring housing suitable for the seal shown in Fig. 2.

Fig. 1 shows a shaft 1 in a shaft housing 2.

A face-sealing ring 3, of carbon or like material as known for such face-sealing rings, is urged into relatively rotatable face-sealing contact with a counterface ring 4, of hardened stainless steel or similar hard material, by a coiled compression spring 5, such as of stainless steel, carrying a sealing ring housing 6 of stainless steel, or any suitable material e.g. a moulded plastics material. The face-sealing ring 3 and its housing 6 in combination form a space for a rubber or like resiliently-deformable '0' ring 7, which provides a static seal around the shaft 1, and the counterface ring 4 and shaft housing 2 are provided with a static seal by a similar '0' ring 8. The spring 5 abuts axially against a shoulder 9 on the shaft 1.

The face-sealing ring 3 is adhesively secured in the housing 6 in axial abutment against a shoulder 10 in the housing. The adhesive can be of any type suitable for the eventual operating conditions. For a seal for small industrial pumps, such as for water or oil, an anaerobic adhesive is suitable. One example of such an adhesive is the dimethacrylate of ethoxylated bisphenol A.

Fig. 2 shows an alternative construction, designed to reduce the over-all outer diameter of the seal, in which a compression spring 11 extends into the sealing ring housing 1 2 and axially compresses an '0' ring 7, a protecting thrust washer 1 3 being interposed. A radial drive tang 14 engages with the borders of a drive notch 1 5 in the housing 12. The borders of the notch 1 5 may be turned in as shown in Fig. 5.

Fig. 3 shows an alternative more advantageous geometry for use when it is required that the face-sealing ring 1 6 is of harder material than the counterface ring 17. In this arrangement the counterface ring has a smaller radial width than the sealing ring in the face sealing plane, so as to provide for wear without causing a groove.

Fig. 4 shows another reduced outer diameter seal in which a reduced diameter rear end 1 8 of the sealing ring housing 1 9 provides a spigot for anchorage of the compression spring 20 within the over-all diameter of the sealing ring housing. In Fig. 4 the shaft is shown with a step 21 and it can be seen that the face-sealing ring 22 is correspondingly shaped, the design permitting such modification without major structural change.

1. A mechanical face-seal comprising a face-sealing ring and a counterface ring, both of rigid material, with a coiled compression spring for loading the face-sealing ring axially into relatively rotatable face-sealing contact against the counterface ring, the face-sealing ring and counterface ring being provided with resiliently-deformable sealing rings, for static sealing respectively on a shaft and in a shafthousing, and the face-sealing ring being carried by a surrounding housing which in turn is carried by the coiled compression spring for mounting on a shaft, in which the face-sealing ring is adhesively secured in its housing in axial abutment against a shoulder in its hous

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Mechanical seal for preventing fluid leakage This invention relates to mechanical seals for preventing fluid leakage and in particular socalled face-seals for preventing leakage along rotary shafts, in pumps for example. The invention aims at the provision of a simple low-cost seal comprising a small number of parts which can easily be assembled and installed. For the above purpose, the invention is applied to a mechanical face-seal comprising a face-sealing ring and a counterface ring, both of rigid material, with a coiled compression spring for loading the face-sealing ring axially into relatively rotatable face-sealing contact against the counterface ring, the face-sealing ring and counterface ring being provided with resiliently-deformable sealing rings, for static sealing respectively on a shaft and in a shafthousing, and the face-sealing ring being carried by a surrounding housing which in turn is carried by the coiled compression spring for mounting on a shaft. The spring acts as a drive spring for rotation of the seal with the shaft. According to the invention, in a seal of the above kind, the face-sealing ring is adhesively secured in its housing in axial abutment against a shoulder in its housing and an inner face of the face-sealing ring together with an adjacent wall portion of its housing provide axial and surrounding circumferential location surfaces for a resiliently-deformable shaft-sealing ring. Such securing of the face-sealing ring provides very simply for sealing of the facesealing ring in its housing, with effective prevention of relative rotation under face-drag in use, and also provides for location of the face-sealing ring by axial and circumferential abutment surfaces, when the seal is mounted on a shaft. The invention also includes other advantageous features, for axial spring-loading of the shaft-sealing ring and for reducing the over-all diameter of the seal, which are included in the following description with reference to the accompanying drawing, wherein:- Figures 1 to 4 show half axial sections of four embodiments of seals according to the invention, and Figure 5 shows a perspective view of a sealing ring housing suitable for the seal shown in Fig. 2. Fig. 1 shows a shaft 1 in a shaft housing 2. A face-sealing ring 3, of carbon or like material as known for such face-sealing rings, is urged into relatively rotatable face-sealing contact with a counterface ring 4, of hardened stainless steel or similar hard material, by a coiled compression spring 5, such as of stainless steel, carrying a sealing ring housing 6 of stainless steel, or any suitable material e.g. a moulded plastics material. The face-sealing ring 3 and its housing 6 in combination form a space for a rubber or like resiliently-deformable '0' ring 7, which provides a static seal around the shaft 1, and the counterface ring 4 and shaft housing 2 are provided with a static seal by a similar '0' ring 8. The spring 5 abuts axially against a shoulder 9 on the shaft 1. The face-sealing ring 3 is adhesively secured in the housing 6 in axial abutment against a shoulder 10 in the housing. The adhesive can be of any type suitable for the eventual operating conditions. For a seal for small industrial pumps, such as for water or oil, an anaerobic adhesive is suitable. One example of such an adhesive is the dimethacrylate of ethoxylated bisphenol A. Fig. 2 shows an alternative construction, designed to reduce the over-all outer diameter of the seal, in which a compression spring 11 extends into the sealing ring housing 1 2 and axially compresses an '0' ring 7, a protecting thrust washer 1 3 being interposed. A radial drive tang 14 engages with the borders of a drive notch 1 5 in the housing 12. The borders of the notch 1 5 may be turned in as shown in Fig. 5. Fig. 3 shows an alternative more advantageous geometry for use when it is required that the face-sealing ring 1 6 is of harder material than the counterface ring 17. In this arrangement the counterface ring has a smaller radial width than the sealing ring in the face sealing plane, so as to provide for wear without causing a groove. Fig. 4 shows another reduced outer diameter seal in which a reduced diameter rear end 1 8 of the sealing ring housing 1 9 provides a spigot for anchorage of the compression spring 20 within the over-all diameter of the sealing ring housing. In Fig. 4 the shaft is shown with a step 21 and it can be seen that the face-sealing ring 22 is correspondingly shaped, the design permitting such modification without major structural change. CLAIMS

1. A mechanical face-seal comprising a face-sealing ring and a counterface ring, both of rigid material, with a coiled compression spring for loading the face-sealing ring axially into relatively rotatable face-sealing contact against the counterface ring, the face-sealing ring and counterface ring being provided with resiliently-deformable sealing rings, for static sealing respectively on a shaft and in a shafthousing, and the face-sealing ring being carried by a surrounding housing which in turn is carried by the coiled compression spring for mounting on a shaft, in which the face-sealing ring is adhesively secured in its housing in axial abutment against a shoulder in its hous ing, and an inner face of the face-sealing ring together with an adjacent wall portion of its housing provide axial and surrounding circumferential location surfaces for a resiliently-deformable shaft-sealing ring.

2. A mechanical face-seal according to claim 1, in which the resiliently-deformable face-sealing ring is loaded in axial compression by the coiled compression spring extending into the face-sealing ring housing.

3. A mechanical face-seal according to claim 2, in which a thrust washer is axially interposed between the spring and shaft-sealing ring.

4. A mechanical face-seal according to claim 1, in which the face-sealing ring housing has a rear end portion of reduced diameter providing a spigot for anchorage thereon of the coiled compression spring within the over-all diameter of the housing around the face-sealing ring.

5. A mechanical face-seal as described with reference to and as shown by any of Figs. 1 to 5 of the accompanying drawing.