GB2251399A

GB2251399A - Apparatus for abrasive treatment of surfaces

Info

Publication number: GB2251399A
Application number: GB9125950A
Authority: GB
Inventors: Norman Lewis Williams
Original assignee: WILLIAMS N L ENG Ltd
Current assignee: WILLIAMS N L ENG Ltd
Priority date: 1990-12-06
Filing date: 1991-12-06
Publication date: 1992-07-08
Anticipated expiration: 2011-12-06
Also published as: GB9026607D0; GB2251399B; GB9125950D0

Abstract

Apparatus for surface treatment comprises an impeller 11 for forcing particulate material e.g. steel shot against a surface 19, a mixture of shot and debris from the surface pass up a return channel R to a receiving unit T and then to a filter unit 60. The receiving unit provides a defined discharge outlet in the form of a slot, whose width can be adjusted by movable plates. A suction fan 50 produces suction between upper and lower walls 33, 35 of the receiving unit to provide suction at a top part of the outlet from the return channel R for the removal of fine dust. The filter unit includes a filter element of inverted V-shape. <IMAGE>

Description

APPARATUS FOR SURFACE TREATMENT This invention relates to apparatus for surface treatment.

Apparatus for abrasive treatment of surfaces is known; British Patent Specification 2203368 is an example. In this, particulate abrasive is delivered along a delivery section to hit and abrade a surface to be treated, and the abrasive, mixed with debris from the surface, passes along up a rebound section.

According to this invention apparatus for surface treatment comprises a delivery channel, means for delivering particulate material along the delivery channel to a surface to be treated, a return channel for a mixture of particulate material and debris from the surface,and a receiving section for receiving the mixture from the return channel, the receiving section providing a defined discharge outlet for mixture.

The outlet may be a slot The slot may extend away from the return channel.

The return channel may comprise an upper continuously curved portion having a delivery outlet directed towards the receiving section.

There may be suction means for removing dust from mixture leaving the return channel.

The receiving section may be shaped to connect the suction to a top part of the delivery outlet.

The receiving section may have upper and lower walls above a bottom wall, between which upper and lower walls the suction can be directed to said top part.

The discharge outlet may be adjustable. There may be adjustable plates defining opposite sides of the discharge outlet.

There may be a filter section to which mixture passes from the discharge outlet.

The invention also provides apparatus for surface treatment comprising a delivery channel, means for delivering particulate material along the delivery channel to a surface to be treated, a return channel for a mixture of particulate material and debris from the surface, and a receiving section for receiving the mixture from the return channel, the receiving section having a filter element of inverted V-shape.

The invention may be performed in various ways and one specific embodiment with possible modifications will now be described by way of example with reference to the accompanying somewhat diagrammatic drawings, in which: Fig. 1 is a sideview part in section of surface abrading apparatus; Fig. 2 is a perspective view of a receiving section; Fig. 3 is a transverse cross-section of Fig. 2; Fig. 4 is a part section on the line 4-4 of Fig. 3; Fig. 5 is a perspective view of a filter section; Fig. 6 is a transverse section of Fig. 5; and Fig. 7 is a plan view part cut away of part cf Fig. 5.

Apparatus 10 for treating surfaces comprises a delivery section D including an impeller 11 mounted in an abrasive delivery channel 12 for rotation about an axis 13 by an electric or hydraulic motor 14.

The impeller has a plurality of angularly spaced radial blades 15 each lying in a plane containing the axis 13. The speed of the impeller can be varied.

Particulate abrasive material, for example steel shot 16, is admitted to the channel 12 through an axial input conduit 17 under the control of a manually operable valve 18 and is flung by the impeller along the channel 12 to hit a surface 19 to be treated.

The channel 12 has an uninterrupted delivery mouth 20 extending across the lower end of the channel 12.

The shot 16 hits the surface 19 at a very high speed and removes pieces from the surface to form debris.

The shot rebounds from surface 19 and passes with the debris up a rebound section R to a reclaim section T.

The section R is a channel 21 which has a uniform or increasing cross-section area as it extends upwards.

At the top channel 21 is continued by curved walls 22, 23, with an internal curved baffle 24, leading to downwards and rearwards directed mouth 25. All this return or rebound material is received through a front mouth 30 into a receiving unit 31. This has a top wall 32 which slopes downwards from front to rear and downwards and sideways from a central ridge 33 and spaced above an inner top wall 34 which also slopes down rearwards and sideways from a central ridge 35.

The vertical side walls 36,37 of unit 31 are inclined towards each other as they extend rearwards to a rear wall 38. Wall 34 extends to a rear wall 39 spaced forwards from wall 38 to leave a gap 40 open at the front at 41 above the rear end 22a of wall 22.

The unit 31 has lower walls 42 which are inclined inwards to a central slot or opening 43 so as to direct shot and debris to the slot 43. Plates 44 may be mounted on the underside of walls 42 to define the sides of slot 43 and may be adjustable so as to vary the width of slot 43. The height of walls 36,37 is reduced as the walls extend rearwards.

An extractor fan 50 withdraws air and fine dust debris as shown by arrows 51 and this includes flow through gap 40. Thus a top layer of air, with dust, is removed from the return flow through mouth 41, as indicated by arrows 52.

All the rebound material apart from that removed by fan 50 is thus directed through the central slot 43 which extends fore-and-aft, the apparatus in use moving in the direction of arrow A Fig.l, away from the return channel R.

The return shot and debris falls from opening 43 into filter unit 60. This comprises outer tundish 61 and inner tundish 62. These have spaced vertical side walls 63, 64 and spaced apart inclined end walls 65, 66.

A larger mesh filter 67 of inverted V shape in cross-section has its edges sealed to the inner surfaces of the walls of tundish 61 and filters out larger pieces of debris which can be removed as required through openable doors 68. The top of the inner tundish 62 is closed by finer mesh filter 69, also of inverted V shape. Fine dust is removed by the fan 50 as indicated at 70 from material which has passed through slot 43. The filter 69 permits small pieces of debris, and shot which has been reduced by wear to below the size of the mesh of filter Q, to pass through filter 69 to outlet 71 and fall ir.to collector hopper 72 which can be removed.

The intermediate sized material comprising shot and a little debris does not pass through the filter 69 and falls down the filter surface 69 and the sides of the inner tundish 62 and passes through an outlet 73 in the rear end wall of the tundish into the channel 17 and thus back to the impeller 11.

The channel R is straight sided, with a number of laterally spaced internal flat baffles extending up to the level 80.

The blast or abrading zone 81 is surrounded by a flexible seal 82 and may have one or more openings 83 at the rear for admission of air to assist in returning the shot and debris through channel R.

The opening 43 acts as a control discharge outlet for the return material.

The ridges 33, 35 could be omitted and walls 32, 34 be flat.

In a modification the filter unit is arranged to remove only larger pieces of debris.

The receiving unit 31 serves to slow the movement of the mixture and change the direction of movement of much of the mixture so that this passes through the slot 43 which has a defined shape onto the upper surface 67 of the filter section near the centre line thereof and flows sideways over wall 67.

Some of the mixture may pass directly from mouth 30 to slot 43 whilst retaining significant kinetic energy and thus assist in resisting blockage of slot 43 and in cleaning filter 67.

There could be a number of apertures in the wall 34 for entry of air into the gap 40; for example a number of spaced transverse slots. Each of these apertures would have a downwards lip at their front edge similar to rear end 22a to resist direct entry of shot and debris into the gap 40.

The mouth 30 faces in a different direction from the opening 43.

Claims

1. Apparatus for surface treatment comprising a delivery channel, means for delivering particulate material along the delivery channel to a surface to be treated, a return channel for a mixture of particulate material and debris from the surface,and a receiving section for receiving the mixture from the return channel,the receiving section providing a defined discharge outlet for mixture.

2. Apparatus as claimed in claim 1, in which the outlet is a slot.

3. Apparatus as claimed in claim 2, in which the slot extends away from the return channel.

4. Apparatus as claimed in any preceding claim, in which the return channel comprises an upper continuously curved portion having a delivery outlet directed towards the receiving section.

5. Apparatus as claimed in any preceding claim, including suction means for removing dust from mixture leaving the return channel.

6. Apparatus as claimed in claim 5 with claim 4, in which the receiving section is shaped to connect the suction produced by the suction means to a top part of the delivery outlet.

7. Apparatus as claimed in claim 6, in which the receiving section has upper and lower walls above a bottom wall between which upper and lower walls the suction is directed to the top part.

8. Apparatus as claimed in any preceding claim, in which the discharge outlet is adjustable.

9. Apparatus as claimed in claim 8, including adjustable plates defining opposite sides of the discharge outlet.

10. Apparatus as claimed in any preceding claim, in which the receiving section has walls positioned to direct mixture to the discharge outlet.

11. Apparatus as claimed in any preceding claim, in which the receiving section has a mouth for receiving the mixture, the mouth facing in a different direction from the discharge outlet.

12. Apparatus as claimed in any preceding claim, including a filter section to which mixture passes from the discharge outlet.

13. Apparatus as claimed in claim 11, in which the filter section has an inverted V-shape filter element.

14. Apparatus for surface treatment substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

15. Apparatus for surface treatment comprising a delivery channel, means for delivering particulate material along the delivery channel to a surface to be treated, a return channel for a mixture of particulate material and debris from the surface, and a receiving section for receiving the mixture from the return channel, the receiving section having a filter element of inverted V-shape.