GB2264248A

GB2264248A - Shot blasting apparatus

Info

Publication number: GB2264248A
Application number: GB9303366A
Authority: GB
Inventors: Norman Lewis Williams
Original assignee: WILLIAMS N L ENG Ltd
Current assignee: WILLIAMS N L ENG Ltd
Priority date: 1992-02-21
Filing date: 1993-02-19
Publication date: 1993-08-25
Anticipated expiration: 2013-02-19
Also published as: GB9303366D0; GB9203745D0; GB2264248B

Abstract

Apparatus 10 for surface treatment of articles 13 moved by conveyor 12 through chamber 11 comprises an impeller l4 for projecting shot onto the article 13, a collecting zone 18 for receiving shot and debris from the surface of the article, an elevator 19 delivering the mixture to a scalping drum 20 and a filter unit 22 including larger mesh filter 22a and smaller mesh filter 24 so that particles of intermediate size can return on passage 26 to the impeller 14. Wear of the impeller and surface of chamber 11 is reduced. <IMAGE>

Description

IINPROVET;ENT7S II7 SURFACE TREATMENT APPARATUS This invention relates to surface treatment apparatus.

According to this invention apparatus for surface treatment of articles comprises a treatment chamber, means for propelling particulate raterial into the chamber to treat an article in the chamber, and means for conveying a mixture of particulate material and debris from the chamber to an input to the propelling means, the conveying means comprising means for removal from the mixture of particles of less than a predetermined size.

There may be means for removing particles of more than a size larger than the predetermined size.

The removal an removing means may comprise or or separating means.

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 diagrammatic drawing which illustrates apparatus for surface treatment of workpieces.

The apparatus 10 comprises treatment or blasting chamber 11, a conveyor 12 for conveying through the chamber 11 a succession of workpieces or articles 13 to be treated, and a rotary device 14 for propelling particulate material 15 e.g. shot to hit and abrade the surface of the article 13. A mixture of the material 15 and debris from the surface of the article fall to the bottom of the chamber 11 and pass under the control of gravity and a feed device 16 through one or more passages 17 to a collecting zone 18.

elevator device 19 lifts the mixture to the to-o- and discharges the mixture into a rotary scalping drum 20. mhe drum 20 has a rotary cylindrical mesh and larger particles of debris do not pass through the mesh but are removed through outlet 21.

The mixture which passes through the mesh into the interior of the drum 20 flows along passage 21a to the top of a filter chamber 22. In this an upper mesh 22a removes larger items e.g. nails which may have passed through the drum 20. These larger items can be removed through closable side doors 23.

The mixture which passes through mesh 22a largely falls onto a filter 24 of smaller mesh size than the mesh 22a and slightly spaced from chamber 22 at 24a.

The small dimension shot and debris which pass through the filter 24 pass on passage 25a to a removal hopper 25. The intermediate size debris and the particulate material which does not pass through the filter 24 move around filter 24 and along passage 26 to the input to the device 14 for discharge into chamber 11.

The mixture flows downwards over the inclined mesh 22a, 24 assisting in the filtering effect.

The filters 22a, 24 are of inverted V-shape.

The upper part of the chamber 22 has a suction connection 30 for removal of dust and may have an inlet 31 for air to create an air flow across the upper region of the chamber 22 towards the connection 30 to assist in the removal of dust.

It will be understood that as the particulate material is worn down by use it will reach a size at which it is removed through filter 24. This helps to maintain consistency of treatment. Fresh particulate material of predetermined size can be added as required, possibly automatically, to the input of device 14.

The feed device 16 may be driven by motor 40 and the motor 40 and various flow control valves 41 in passages 17, 25a, 26 may be controlled by control means 42 as required or desired, in particular to avoid undesirable build up of material in any part of the apparatus.

With this apparatus the fine particles of debris and particulate material are substantially removed from the input to the device 14 and the wear on the device 14 including blast wheel blades and internal wear plates in the chamber 11 thus reduced.

Other lifting means may replace elevator 19.

The articles may be mounted on a rotatable device and be loaded and unloaded through a side door in the chamber 11.

The arrangement removes from the mixture in zone 18 particles of less than a predetermined size and particles of more than a size larger than the predetermined size so that particles of an intermediate size are delivered to the device 14.

The articles 13 can be rotated whilst being treated.

Means may be provided for vibrating the filters or particle separators 22a, 24.

Claims

1. Apparatus for surface treatment of articles comprising a treatment chamber, means for propelling particulate material into the chamber to treat an article in the chamber, and means for conveying a mixture of particulate material and debris from the chamber to an input to the propelling means, the conveying means comprising means for removal from the mixture of particles of less than a predetermined size.

2. Apparatus as claimed in Claim 1, comprising means for moving an article relative to the propelling means.

3. Apparatus as claimed in Claim 1 or Claim 2, including a conveyor for moving articles through the chamber.

4. Apparatus as claimed in any preceding claim, including means for removal from the mixture of particles of a size greater than a size larger than the predetermined size.

5. Apparatus as claimed in any preceding claim, in which the removal means comprises filter means.

6. Apparatus as claimed in Claim 5, in which the filter means comprises an upper filter and a lower filter of a mesh size smaller than the upper filter, and passage means for material which does not pass the lower filter to pass to the propelling means.

7. Apparatus as claimed in Claim 6, in which the upper and lower filters are of inverted V-shape.

8. Apparatus for surface treatment of articles substantially as hereinbefore described with reference to and as shown in the accompanying drawing.