GB2026904A

GB2026904A - Rotary atomiser

Info

Publication number: GB2026904A
Application number: GB7923947A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-08-02
Filing date: 1979-07-10
Publication date: 1980-02-13
Also published as: GB2026904B

Abstract

A rotary atomiser has a rotary dispension member with a planar central portion (1) and a sloping peripheral wall (2) so that, on rotation, liquid is fed by centrifugal force along the inner surface of the wall and is discharged from the rim. The inner wall surface has grooves (6) radially aligned with teeth (7) on the rim. The streams of liquid proceeding along each groove to each tooth are kept separate and are prevented from moving circumferentially around the rim by making the base of each groove terminate at a point (8) which is at a radius from the centre of the member at least as great as the radius of the root (9) of each tooth. <IMAGE>

Description

SPECIFICATION Rotary atomisers This invention relates to rotary atomisers of the kind which include a disc or plate onto which liquid to be atomised is fed, rotation of the disc or plate resulting in migration of the liquid to the periphery of the disc or plate and the issuance of a stream of droplets from said periphery.

In my earlier UK Patent Specification No. 15155111 have described and claimed a disc or plate of a rotary atomiser of the above kind having a peripherally inclined wall formed with grooves along which, in use, liquid travels to the outermost edge of the disc or plate. Thus, UK Patent Specification No.

1515511 claims an atomiser comprising a dished rotary dispersion member having a substantially planar circular central region with a peripheral frusto-conical wall inclined outwardly of the central region, the inner surface of the wall being formed with grooves extending radially outwardly from the central region to the innermost free edge of the wall, and the member being adapted for driving engagement by rotary drive means.

In preferred and claimed embodiments the peripheral wall may be formed at its outermost edge with radially outwardly projecting teeth, the teeth may be disposed at the same angular spacing as the grooves and the apex of each tooth may be in alignment, along a radius of the dispersion member, with the base of a corresponding groove. However, an examination of the specific construction will show that there is a flat face at the rim of the dispersion member between the termination of the grooves and the roots of the teeth. It has been found in practice that with such a construction there is a tendency for the liquid to flow in a circumferential direction upon the flat face and the object of the present invention is to improve the characteristics of the atomiser by minimising such circumferential flow.

According to the present invention, therefore, an atomiser comprising a dished rotary dispersion member having a substantially planar circular central region, the inner surface of the wall being formed with grooves extending radially outwardly from the central region to the innermost free edge of the wall, and the outermost edge of the wall being formed with radially outwardly projecting teeth, disposed at the same angular spacing as the grooves and aligned, along a radius of the dispersion member, so that the apex of each tooth is in alignment with the base of a corresponding groove, is characte rised in that the bases of the grooves terminate at a radius from the centre of the rotary dispersion member at least as great as the radius of the roots of the teeth.

The invention is illustrated with reference to the accompanying drawings in which, Figure 1 is a section through a rotary dispersion member.

Figure 2 is a plan view of a section of a wall of the rotary dispersion member.

Figure 3 is a section through Figure 2 along line Y-Y.

Figure 4 is a view of Figure 3 looking in the direction of arrow A.

Figure 5 is another plan view of a section of a wall of a rotary dispersion member, and Figure 6 is a section through Figure 5 along line x x In the drawings Figure 1 shows a rotary dispersion member having a planar circular central region 1 and a peripheral frusto-conical wall 2. The member is rotatable about its central axis. Walls 3 and 4 are two circular walls, which with projection 5, provide strengthening for the member and serve to position and locate the member on a spindle (not shown). In use, liquid is fed to the central region 1, by any suitable means (not shown) and is propelled, by centrifugal force, along the inner surface of the wall 2 to the rim, from whence it is discharged.

In Figures 2,3 and 4, wall 2 is seen to have, on its inner surface, V-cross sectional grooves 6 which extend from the base of the wall to the rim. The rim of the wall has equi-angularly spaced and radially extending teeth 7 which are equal in number to the grooves 6. The base of each of the grooves 6 is angularly aligned with the tip of a tooth 7. The base of each groove ends at a point 8 which is at a radius from the centre of member 1 which is greater than the radius of the root 9 of each tooth. Liquid being fed along each groove to each tooth cannot easily travel circumferentially around the rim since circumferential movement will involve a component of movement back towards the centre of the disc against the centrifugal force of the rotation.

Figures 5 and 6 are similar to Figures 2 and 3 except that, in this case the bases of the grooves 6 extend to points 8 which are at a radial distance equal to the radial distance of the roots 9 of the teeth, which are squared off. Again, circumferential movement of liquid around the rim is inhibited by centrifugal force.

Other features of the rotary dispersion member may be as for UK Patent Specification No. 1515511.

Thus, the angle of wall 2 to central region 1 may be any convenient angle but is suitably 60 . The number of grooves and teeth may conveniently be from 90 to 360 and the depth of the grooves may be 1/2 - 1 mm.

The disc may have an overall radius of 2 - 5 cm.

Experiments have shown that with a construction as above described, the liquid can be discharged tangentially from the tips of the teeth either as discrete droplets or as filaments of liquid which subsequently break up into reasonably even sized droplets and any tendency for the liquid to be discharged from the rim as a sheet formed by the jointing up of two or more filaments is minimised.

1. An atomiser comprising a dished rotary dispersion member having a substantially planar circular central region with a peripheral frusto-conical wall inclined outwardly of the central region, the inner surface of the wall being formed with grooves extending radially outwardly from the central region to the innermost free edge of the wall, and the

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Rotary atomisers This invention relates to rotary atomisers of the kind which include a disc or plate onto which liquid to be atomised is fed, rotation of the disc or plate resulting in migration of the liquid to the periphery of the disc or plate and the issuance of a stream of droplets from said periphery. In my earlier UK Patent Specification No. 15155111 have described and claimed a disc or plate of a rotary atomiser of the above kind having a peripherally inclined wall formed with grooves along which, in use, liquid travels to the outermost edge of the disc or plate. Thus, UK Patent Specification No. 1515511 claims an atomiser comprising a dished rotary dispersion member having a substantially planar circular central region with a peripheral frusto-conical wall inclined outwardly of the central region, the inner surface of the wall being formed with grooves extending radially outwardly from the central region to the innermost free edge of the wall, and the member being adapted for driving engagement by rotary drive means. In preferred and claimed embodiments the peripheral wall may be formed at its outermost edge with radially outwardly projecting teeth, the teeth may be disposed at the same angular spacing as the grooves and the apex of each tooth may be in alignment, along a radius of the dispersion member, with the base of a corresponding groove. However, an examination of the specific construction will show that there is a flat face at the rim of the dispersion member between the termination of the grooves and the roots of the teeth. It has been found in practice that with such a construction there is a tendency for the liquid to flow in a circumferential direction upon the flat face and the object of the present invention is to improve the characteristics of the atomiser by minimising such circumferential flow. According to the present invention, therefore, an atomiser comprising a dished rotary dispersion member having a substantially planar circular central region, the inner surface of the wall being formed with grooves extending radially outwardly from the central region to the innermost free edge of the wall, and the outermost edge of the wall being formed with radially outwardly projecting teeth, disposed at the same angular spacing as the grooves and aligned, along a radius of the dispersion member, so that the apex of each tooth is in alignment with the base of a corresponding groove, is characte rised in that the bases of the grooves terminate at a radius from the centre of the rotary dispersion member at least as great as the radius of the roots of the teeth. The invention is illustrated with reference to the accompanying drawings in which, Figure 1 is a section through a rotary dispersion member. Figure 2 is a plan view of a section of a wall of the rotary dispersion member. Figure 3 is a section through Figure 2 along line Y-Y. Figure 4 is a view of Figure 3 looking in the direction of arrow A. Figure 5 is another plan view of a section of a wall of a rotary dispersion member, and Figure 6 is a section through Figure 5 along line x x In the drawings Figure 1 shows a rotary dispersion member having a planar circular central region 1 and a peripheral frusto-conical wall 2. The member is rotatable about its central axis. Walls 3 and 4 are two circular walls, which with projection 5, provide strengthening for the member and serve to position and locate the member on a spindle (not shown). In use, liquid is fed to the central region 1, by any suitable means (not shown) and is propelled, by centrifugal force, along the inner surface of the wall 2 to the rim, from whence it is discharged. In Figures 2,3 and 4, wall 2 is seen to have, on its inner surface, V-cross sectional grooves 6 which extend from the base of the wall to the rim. The rim of the wall has equi-angularly spaced and radially extending teeth 7 which are equal in number to the grooves 6. The base of each of the grooves 6 is angularly aligned with the tip of a tooth 7. The base of each groove ends at a point 8 which is at a radius from the centre of member 1 which is greater than the radius of the root 9 of each tooth. Liquid being fed along each groove to each tooth cannot easily travel circumferentially around the rim since circumferential movement will involve a component of movement back towards the centre of the disc against the centrifugal force of the rotation. Figures 5 and 6 are similar to Figures 2 and 3 except that, in this case the bases of the grooves 6 extend to points 8 which are at a radial distance equal to the radial distance of the roots 9 of the teeth, which are squared off. Again, circumferential movement of liquid around the rim is inhibited by centrifugal force. Other features of the rotary dispersion member may be as for UK Patent Specification No. 1515511. Thus, the angle of wall 2 to central region 1 may be any convenient angle but is suitably 60 . The number of grooves and teeth may conveniently be from 90 to 360 and the depth of the grooves may be 1/2 - 1 mm. The disc may have an overall radius of 2 - 5 cm. Experiments have shown that with a construction as above described, the liquid can be discharged tangentially from the tips of the teeth either as discrete droplets or as filaments of liquid which subsequently break up into reasonably even sized droplets and any tendency for the liquid to be discharged from the rim as a sheet formed by the jointing up of two or more filaments is minimised. CLAIMS

1. An atomiser comprising a dished rotary dispersion member having a substantially planar circular central region with a peripheral frusto-conical wall inclined outwardly of the central region, the inner surface of the wall being formed with grooves extending radially outwardly from the central region to the innermost free edge of the wall, and the outermost edge of the wall being formed with radially outwardly projecting teeth, disposed at the same angular spacing as the grooves and aligned, along a radius of the dispersion member, so that the apex of each tooth is in alignment with the base of a corresponding groove, characterised in that the bases of the grooves terminate at a radius from the centre of the rotary dispersion member at least as great as the radius of the roots of the teeth.

2. An atomiser as claimed in claim 1 substantially as described with reference to the drawings.