GB2131379A

GB2131379A - Improvements in or relating to methods of and apparatus for, elevating particulate material

Info

Publication number: GB2131379A
Application number: GB08331977A
Authority: GB
Inventors: Ronald William Curtis
Original assignee: CURTIS VIBRATORS; Baker Perkins Ltd
Current assignee: CURTIS VIBRATORS; Baker Perkins Ltd
Priority date: 1982-12-04
Filing date: 1983-11-30
Publication date: 1984-06-20
Also published as: GB8331977D0

Abstract

A foundry sand reclamation plant 1 comprises a lump break-down and shake-out unit 2, a vibratory attrition unit 3, a vibration generator 5, and apparatus 6 for elevating particulate material (sand) to a classifier 7. The elevating apparatus 6 comprises a closed duct or casing 15 of elongated form disposed substantially vertically with its lower end mounted on the attrition unit 3. The casing 15 has a substantially rectangular (lateral) cross-section. One wall 16 of the casing is of saw-tooth form whereby it defines a plurality of juxtaposed pockets or hollows 17 disposed in seriatim, one above the above. The hollows 17 are spaced from and face the opposite wall 18 of the casing which is substantially flat. In operation, the casing 15 is vibrated as indicated by arrow 50. Particulate material introduced into the lower end of the casing 15, at inlet 20, is then caused to be elevated along a substantially linear path, indicated by arrows 30, along the space between the openings of the hollows 17 and the wall 18 opposite. At the same time, particulate material is caused to be elevated by way of a series of rotary paths, as indicated by arrows 31, passing upwardly from hollow to hollow. <IMAGE>

Description

SPECIFICATION Improvements in or relating to methods of and apparatus for, elevating particulate material This invention relates to methods of, and apparatus for, elevating particulate material.

The invention has particular application to the reclamation of chemically bonded moulding sand from foundry moulds and cores.

There are basically three sand reclamation techniques, namely dry, wet and thermal reclamation methods. A common initial stage of all three methods is the breaking down of sand agglomerates to grain size. This is usually achieved by crushing and shake-out. Although currently available machinery is reasonably effective at producing grain size material, it would be desirable if their scrubbing actions were more efficient.

The dry method of sand reclamation comprises breaking open a mould so as to remove the casting it contains, reducing the sand lumps to grain size, and using mechanical abrasion to separate the chemical binder from the sand grains.

Supplementary apparatus such as cyclone separators and classifiers may be used to obtain substantially clean sand which has been screened and from which all "fines" or dust has been removed.

Mechanical and pneumatic scrubbing apparatus take several forms. With reference to British Patent No. 1,422,252 (Baker Perkins Holdings Limited), agglomerates containing sand to be reclaimed is pneumatically conveyed upwards through a conduit at high velocity to strike a wear-resistant target or breaker plate. This causes breakdown and scrubbing of the sand agglomerates. Further breakdown and scrubbing occurs in a cyclone separator within which are mounted further breaker plates.

According to one aspect of the present invention, a method of elevating particulate material comprises introducing the material into a lower part of a duct of elongated form disposed so as to extend upwardly, and vibrating the. duct, the form of the duct and the effect of the vibration being such that particulate material is caused to be elevated along a substantially linear path as well as a succession of rotary paths.

According to another aspect of the invention, apparatus for elevating particulate material comprises a resiliently mounted casing of elongated form disposed so as to extend upwardly, at least one wall of the casing defining a plurality of juxtaposed hollows disposed in seriatim, one above the other, the hollows being spaced from and facing the opposite wall of the casing, and means for vibrating the casing, the arrangement being such that material introduced into a lower part of the casing is caused to be elevated along a substantially linear path along the space between the hollows and said opposite wall as well as by way of a series of rotary paths passing from hollow to hollow.

As used herein, "extend upwardly" is intended to include not only vertically, but also inclined to the vertical.

The invention also comprises foundry sand reclamation plant provided with the elevating apparatus.

An embodiment of the invention will now be described by way of example only, with reference to the accompanying diagrammatic drawings, wherein Figure 1 is a side view, partly in section, of a sand reclamation plant, Figure 2 is an enlarged view of the box II of Figure 1, and Figures 3 to 9 are sectional views of modified elevating apparatus.

In the figures, like reference numerals refer to like components.

With reference to Figure 1, a foundry sand reclamation plant 1 comprises a lump break-down and shake-out unit 2, a vibratory attrition unit 3 disposed on resilient mountings 4, vibrations being set up by vibratory means, apparatus 6 for elevating particulate material (sand) to a classifier 7 for subsequent transfer to a hopper 8, and a storage container 9. A dust extraction system 10 is connected to the upper end of the elevating apparatus 6 by a line 11.

The vibratory means comprise a pair of vibration generators 5, disposed side-by-side.

Thus only one generator 5 appears in Figure 1.

The elevating apparatus 6 comprises a closed duct or casing 1 5 of elongated form disposed substantially vertically. The lower end of the casing 1 5 is secured to the attrition unit 3. The casing 1 5 is therefore resiliently mounted.

The casing 1 5 has a substantially rectangular (lateral) cross-section. One wall (1 6) of the casing is of saw-tooth form whereby it defines a plurality of juxtaposed pockets or hollows 1 7 disposed in seriatim, one above the other. The hollows 1 7 are spaced from and face the opposite wall (1 8) of the casing. The wall 1 8 is substantially flat. Each hollow 1 7 has an upwardly and outwardly inclined lower surface 28 and a substantially horizontal upper surface 29.

Particulate material is introduced into the lower end of the casing 1 5 at inlet 20 and is subsequently discharged from the casing at outlet 21.

In operation, the casing 1 5 is vibrated with a linear oscillatory motion, as indicated by reference 50. The path of the motions so generated is inclined at about 450 to the vertical.

With additional reference to Figure 2, the form of the casing 1 5 and the effect of the vibration are such that particulate material introduced into the lower end of the vibrating casing 1 5, at inlet 20 (Figure 1), is caused to be elevated along a substantially linear path, indicated by arrows 30, extending along the space between the openings of the hollows 17 and the wall 18 opposite. At the same time, particulate material is caused to be elevated by way of a series of swirling or rotary paths of elliptical form, passing upwardly from hollow 17 to hollow 17. The swirling paths are indicated by arrows 31.

Particulate material flowing along the two paths intermixes and is elevated through the casing 1 5 with high efficiency.

Beneficial scrubbing action takes place as the material is passed upwardly through the casing 1 5.

There is a substantially 2:1 ration between lateral dimensions A and B of the casing 1 5. Thus each of the rotary paths (arrows 31) is substantially greater in width than the width of the substantially linear path (arrows 30).

Figures 3 to 8 illustrate modified ducts or casings 1 5a etc., with hollows of varying form.

In Figure 3, hollows 1 7a have upper (29a) and lower (28a) surfaces which do not come together.

Figure 5 shows a similar arrangement but here the upper surface 29c of a hollow 1 7c is downwardly and outwardly inclined and the lower surface 28c thereof is substantially horizontal.

In the casings of Figures 4, 6 and 7, hollows 1 7b etc. are formed between substantially parallel baffle plates 35b, 35d, 35e extending inwardly, into the casing 15, from the walls 1 6b, 1 6d, 1 6e.

In Figure 4 baffle plates 35b are substantially horizontal; in Figure 6 baffle plates 35dslope downwardly from wall 16d, and in Figure 7 baffle plates 35e slope upwardly from wall 16e.

The hollows 17 etc. need not be angular. In Figure 8 a casing 1 5f has hollows 1 7f with curved outer extremities 40.

Figure 9 illustrates a casing 45, which, in effect, comprises a pair of casings 1 5 disposed back-toback with wall 1 8 removed. Thus identicallyshaped opposite walls (46 and 48) each define hollows 47. This results in the generation of an upwardly moving central linear path or stream of particulate material flanked by pairs of rotating paths thereof. As illustrated, each oppositelyfacing wall (46 or 48), is substantially of the form of wall 16 of Figures 1 and 2. However, any of the wall forms 1 6a ... 1 6f of Figures 3 to 7 may be used as alternatives in an oppositely-facing arrangement.

Disposing a casing 1 5 etc. substantially vertically is not critical but it does result in valuable saving of lateral space.

The invention provides an elevator of simple construction which avoids the need for a floor pit as often used to accommodate the lower end of a duct or casing of an elevator.

In a modification, vibration may be imparted to casing 1 5 etc. such that an elliptical path is generated, as indicated by reference 25 of Figure 1. The major axis of the ellipse, like the linear path indicated by reference 50, is inclined at about 45 to the vertical.

The elevating apparatus may comprise an entity separate from the attrition unit 3.

Claims

1. A method of elevating particulate material comprising introducing the material into a lower part of a duct of elongated form disposed so as to extend upwardly, and vibrating the duct, the form of the duct and the effect of the vibration being such that particulate material is caused to be elevated along a substantially linear path as well as a succesion of rotary paths.

2. The method of Claim 1, wherein each of the rotary paths is substantially greater in width than that of the substantially linear path.

3. Apparatus for elevating particulate material, comprising a resiliently mounted casing of elongated form disposed so as to extend upwardly, at least one wall of the casing defining a plurality of juxtaposed hollows disposed in seriatim, one above the other, the hollows being spaced from and facing the opposite wall of the casing, and means for vibrating the casing, the arrangement being such that material introduced into a lower part of the casing is caused to be elevated along a substantially linear path along the space between the hollows and said opposite wall as well as by way of a series of rotary paths passing from hollow to hollow.

4. Apparatus as claimed in Claim 3, wherein said opposite wall of the casing is substantially flat.

5. Apparatus as claimed in Claim 3 or 4, wherein each hollow has an upwardly and outwardly inclined lower surface and a substantially horizontal upper surface.

6. Apparatus as claimed in Claim 3 or 4, wherein each hollow has an outwardly and downwardly inclined lower surface and a substantially horizontal upper surface.

7. Apparatus as claimed in Claim 3 or 4, wherein each hollow is formed between substantially parallel baffle plates extending inwardly, into said casing from said one wall.

8. Apparatus as claimed in Claim 7, wherein the baffle plates are substantially horizontal.

9. Apparatus as claimed in Claim 7, wherein the baffle plates slope downwardly from said one wall.

10. Apparatus as claimed in Claim 7, wherein the baffle plates slope upwardly from said one wall.

11. Apparatus as claimed in Claim 3, or in any one of Claims 5 to 10 (but excluding any reference to Claim 4 therein), wherein oppositely-facing walls of the casing define said hollows.

1 2. Foundry sand reclamation plant provided with apparatus for elevating particulate material, as claimed in any one of Claims 3 to 11.

1 3. A method of elevating particulate material substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.

14. A method of elevating particulate material substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings, modified substantially as hereinbefore described with reference to any one of Figures 3 to 9 of said drawings.

1 5. Apparatus for elevating particulate material, substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.

1 6. Apparatus for elevating particulate material, substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings, modified substantially as hereinbefore described with reference to any one of Figures 3 to 9 of said drawings.

1 7. Foundry sand reclamation plant, substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.

1 8. Foundry sand reclamation plant, substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings, modified substantially as hereinbefore described with reference to any one of Figures 3 to 9 of said drawings.