GB2179710A - Rotating seal assembly - Google Patents

Abstract

A rotating seal assembly has one sealing member 26 mounted on a rotatable shaft 21 by means of a collar 22 and an engaging sealing member 32 mounted on a housing 31 which defines a fluid circulation chamber 34 with the shaft. A vane 12 on the collar 22 is provided to circulate fluid in the chamber 34 as the shaft rotates. The shaft sealing member 26 is preferably connected to the collar 22 by axially deformable means 28. <IMAGE>

Description

SPECIFICATION Rotating seal assembly This invention relates to a rotating seal assembly between a shaft and a housing which assembly requires a circulation of cooling fluid for the seal faces. The casing is formed with a fluid circulation chamber and previously a machined pumping ring has been provided on the shaft to cause the circulation as the shaft rotates in the housing. This has been expensive and the present invention has been made to utilise a low cost replacement for the machined ring.

According to the invention there is provided a rotating seal assembly as set out in claim 1 of the claims of the present specification.

An example of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a plan of a washer, Figure 2 is a side elevation of the washer of Fig. 1, Figure 3 is a section through a washer located between a bolt head and a drive collar in a mechanical seal, Figure 4 is a section through the apparatus of Fig. 1 at right angles to that of Fig. 3, and Figure 5 shows further components of the seal of Figs. 3 and 4, forming a rotating seal assembly.

The washer 10 of Fig. 1 and 2 is generally rectangular in shape. It has a central aperture 11 and upturned ends 12 on two opposite sides with a curved transition between the ends 12 and the central portion 13. The rim 14 of the central aperture 11 is deformed upwards from the general plane of the central portion 13 by a distance of approximately two thirds of the thickness of the washer. The upwards deformation of the rim 14 is symmetrical around the periphery of the hole 11.

The deformation could be downwards if preferred.

The seal shown in Figure 5 has a rotatable shaft 21 provided with a driving collar 22 having a threaded hole 23 into which a bolt 24 is threaded. The shank of the bolt 24 extends into a tangential groove 25 in the shaft 21, the width of the groove being greater than the diameter of the bolt shank, in order to eliminate distortion of the shaft. A sealing ring 26 is mounted on a holder 27 secured to the collar 22 by a bellows 28, in order to allow small relative movement between the sealing ring and the collar 22. The seal is enclosed by a pump casing 31 to which a stationary seal 32 is secured, the engaging faces of the sealing ring 26 and the stationary seal 32 being in a plane at right angles to the axis of rotation and accurately flat.It will be noted that the pump casing 31 forms a fluid circulation chamber 34 and is provided with a circulation port 33 entering the chamber opposite the head of the bolt 24 which is provided with its locking washer 10 as described above. The bolt 24 has a pan head with rounded corners for ease of flow through the fluid, so that the bolt is not distorted by the resistance of the fluid, causing the collar to be pulled out of round. The upstanding edges 12 of the washer 10 lead and trail the head of the bolt 24 to form fluid circulating vanes which create turbulence in the fluid within the chamber 34.

The upturned ends 12 of the washer act are spaced from the bolt head and act as pumping paddles to provide positive flow for barrier fluid cooling or heating of seal faces, so that it is not necessary to rely on thermosyphoning or expensive auxiliary pumping systems.

The washer 10 can be made by stamping or moulding. It provides a part which provides circulation at a much lower cost than a machined pumping ring, for example. The use of a vane on the locking washer rather than the use of the securing bolt to create circulation avoids stresses on the driving collar.

1. A rotating seal assembly comprising a rotatable shaft, a housing defining a circulation chamber around the shaft, a collar on the shaft, mutually engageable sealing members mounted respectively on the housing and on the shaft, the members having engaging faces in a plane transverse to the axis of rotation and a vane separate from but mounted on said collar for driving fluid around said circulation chamber.

2. An assembly as claimed in Claim 1 wherein said vane is mounted on said collar by a bolt or screw which also mounts the driving collar on the shaft.

3. An assembly as claimed in Claim 2 wherein said vane comprises part of a locking washer between the head of said screw and said collar.

4. An assembly as claimed in Claim 3 wherein said vane portion of said washer is space from said screw.

5. An assembly as claimed in Claim 3 or Claim 4 wherein said locking washer comprises a non-planar central portion and an upturned end forming said vane portion.

6. An assembly as claimed in Claim 5 comprising an upturned end on either side of said central portion, leading and trailing the central portion in the direction of rotation.

7. An assembly as claimed in any one of Claims 1 to 6 comprising axially deformable means between said collar and the sealing member of said shaft.

8. A rotating seal assembly substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

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

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Rotating seal assembly This invention relates to a rotating seal assembly between a shaft and a housing which assembly requires a circulation of cooling fluid for the seal faces. The casing is formed with a fluid circulation chamber and previously a machined pumping ring has been provided on the shaft to cause the circulation as the shaft rotates in the housing. This has been expensive and the present invention has been made to utilise a low cost replacement for the machined ring. According to the invention there is provided a rotating seal assembly as set out in claim 1 of the claims of the present specification. An example of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a plan of a washer, Figure 2 is a side elevation of the washer of Fig. 1, Figure 3 is a section through a washer located between a bolt head and a drive collar in a mechanical seal, Figure 4 is a section through the apparatus of Fig. 1 at right angles to that of Fig. 3, and Figure 5 shows further components of the seal of Figs. 3 and 4, forming a rotating seal assembly. The washer 10 of Fig. 1 and 2 is generally rectangular in shape. It has a central aperture 11 and upturned ends 12 on two opposite sides with a curved transition between the ends 12 and the central portion 13. The rim 14 of the central aperture 11 is deformed upwards from the general plane of the central portion 13 by a distance of approximately two thirds of the thickness of the washer. The upwards deformation of the rim 14 is symmetrical around the periphery of the hole 11. The deformation could be downwards if preferred. The seal shown in Figure 5 has a rotatable shaft 21 provided with a driving collar 22 having a threaded hole 23 into which a bolt 24 is threaded. The shank of the bolt 24 extends into a tangential groove 25 in the shaft 21, the width of the groove being greater than the diameter of the bolt shank, in order to eliminate distortion of the shaft. A sealing ring 26 is mounted on a holder 27 secured to the collar 22 by a bellows 28, in order to allow small relative movement between the sealing ring and the collar 22. The seal is enclosed by a pump casing 31 to which a stationary seal 32 is secured, the engaging faces of the sealing ring 26 and the stationary seal 32 being in a plane at right angles to the axis of rotation and accurately flat.It will be noted that the pump casing 31 forms a fluid circulation chamber 34 and is provided with a circulation port 33 entering the chamber opposite the head of the bolt 24 which is provided with its locking washer 10 as described above. The bolt 24 has a pan head with rounded corners for ease of flow through the fluid, so that the bolt is not distorted by the resistance of the fluid, causing the collar to be pulled out of round. The upstanding edges 12 of the washer 10 lead and trail the head of the bolt 24 to form fluid circulating vanes which create turbulence in the fluid within the chamber 34. The upturned ends 12 of the washer act are spaced from the bolt head and act as pumping paddles to provide positive flow for barrier fluid cooling or heating of seal faces, so that it is not necessary to rely on thermosyphoning or expensive auxiliary pumping systems. The washer 10 can be made by stamping or moulding. It provides a part which provides circulation at a much lower cost than a machined pumping ring, for example. The use of a vane on the locking washer rather than the use of the securing bolt to create circulation avoids stresses on the driving collar. CLAIMS

1. A rotating seal assembly comprising a rotatable shaft, a housing defining a circulation chamber around the shaft, a collar on the shaft, mutually engageable sealing members mounted respectively on the housing and on the shaft, the members having engaging faces in a plane transverse to the axis of rotation and a vane separate from but mounted on said collar for driving fluid around said circulation chamber.

2. An assembly as claimed in Claim 1 wherein said vane is mounted on said collar by a bolt or screw which also mounts the driving collar on the shaft.

3. An assembly as claimed in Claim 2 wherein said vane comprises part of a locking washer between the head of said screw and said collar.

4. An assembly as claimed in Claim 3 wherein said vane portion of said washer is space from said screw.

5. An assembly as claimed in Claim 3 or Claim 4 wherein said locking washer comprises a non-planar central portion and an upturned end forming said vane portion.

6. An assembly as claimed in Claim 5 comprising an upturned end on either side of said central portion, leading and trailing the central portion in the direction of rotation.

7. An assembly as claimed in any one of Claims 1 to 6 comprising axially deformable means between said collar and the sealing member of said shaft.

8. A rotating seal assembly substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.