WO1994013387A1

WO1994013387A1 - A cyclone separator

Info

Publication number: WO1994013387A1
Application number: PCT/US1993/011763
Authority: WO
Inventors: Robert Andreae
Original assignee: Richerson, Ben, M.
Priority date: 1992-12-04
Filing date: 1993-12-03
Publication date: 1994-06-23
Also published as: AU5738994A; JPH06206011A; CA2091549A1

Abstract

It comprises several passages of a generally spiralled shape in which the direction is inverted at midway and is comprised of at least two prismatic or cylindrical elements (15, 17, 17a) forming at least one spiral, imbricated into each other with their spirals oriented in opposite directions, in such a manner as to define a front wall (15) having at least one inlet opening (E) and a rear wall having at least one outlet openings (S). These openings (E, S) are connected by a part having an approximately constant cross section comprised of a decreasing spiral followed by an increasing spiral.

Description

A CYCLONE SEPARATOR

The object of present invention is a cyclone separator for solid or liquid particles carried in a flow of gas, generally for particles or droplets of paint suspended in a flow of air.

Painting operations in the industry with spray guns are generally carried out in spray booths 1 which are substantially closed and which include a platform 2 on which the worker stands to project or spray paint on articles which are conveyed in front of him along a passage 3 extending transversely through the spray booth 1. Behind this passage, there is a filtering wall 4 comprised of a cyclone separator, followed by a zigzag-shaped filter 5 of the type described for instance in the Swiss Patent 671,154. This zigzag-shaped filter has a service life which depends on the efficiency of the retention in the cyclone separator of the filtering wall 4, and for this reason, this separator must be sufficiently efficient to retain more than 70% of the paint suspended in the flow of air and enable the recovery and the reuse of the paint, in order to reduce costs.

US Patents 4,927,437 and 4,973,341 teach the use of cyclone separators for the recovery of particles of paint and solvent in a flow of air, said separators being comprised of a succession of double direction helicoidal baffles connected by front panels. The efficiency of this cyclone separator is satisfactory and it is in fact possible to recover in a collector the paint flowing along its walls; however, the system is a single structure, it needs a large area of floor space and cannot be dismounted for its periodical cleaning without having to dismount almost the whole spray booth, with the result that all painting operations are suspended for quite an extended period of time.

The present invention is aimed at providing a cyclone separator, in particular for paint particles suspended in a flow of air, which is both highly efficient and easily dismounted for its cleaning. The object of the present invention is a cyclone separator with inversion of flow, which has the characteristics set forth in claim 1.

The appended drawing is a schematic illustration, given by way of example, of an embodiment of the cyclone separator according to the invention.

Figure 1 is a cross-sectional view of a spray booth equipped with a cyclone separator according to the invention. Figure 2 is a perspective view of the filtering wall formed by the cyclone separator and the downstream zigzag-shaped filter.

Figure 3 is a schematic top view of the elements forming a first embodiment of the cyclone separator. Figure 4 is a schematic top view of the elements forming a second embodiment of the cyclone separator.

Figure 5 is a a schematic top view of a third embodiment of the cyclone separator.

Figure 6 is a perspective view of a portion of the separator shown in Figure 5.

Figure 7 is an enlarged view of the angle formed by two panels of the filter, disposed in an angled relationship.

The object of the present invention is the cyclone separator forming the filtering wall 4 of the spray booth shown in cross-section in Figure 1.

This cyclone separator is comprised of a base 6 provided with a system for recovering the paint, comprised of an endless screw 7 driven in rotation inside a tube 8 by a motor 9, for recovering the paint and the solvents dripping into the collector base 6. This endless screw 7 is positioned in an empty space of the base beneath a sloping upper wall 10 of this base. The base is placed directly on the floor of the paint booth and is positioned by a structure comprised of several horizontal crossbeams 12 provided with positioning members (14). These horizontal crossbeams 12 are fastened at their ends either on a frame (not illustrated) or to the sides of the spray booth.

The base 6 is hollow and functions to support the elements of the cyclone placed thereupon, and as a paint collector.

The cyclone separator per se is comprised of several imbricated elements forming the inverted spirals of the separator. The height of the elements is equal to the distance between the base 6 and a screen

11, which is removable or not, and which completes the upper section of the filtering wall.

The filtering wall 9 is comprised of at least one center element 15 and two end elements 17. All the center elements 15 are identical, and so are the end elements.

The center element 15, parallelepipedal or cylindrical has, when viewed from the top, the general shape of a C and a height corresponding to the distance between the base 6 and the screen 11. Each center element 15 has a flat rear wall provided at each one of its lateral ends with a backwards bent portion 15a extending perpendicularly over a distance generally equal at the most to half the width of the rear wall. These backwards bent portions 15a in turn have a back wall portion 15b perpendicular to the corresponding backward bent portion and are located in the same plane while leaving an opening in between. These wall portions 15 are provided with perpendicular rims 15d of a width lesser than half the width of the backward bent portions 15b. Some of the elements 15 can have at the free end of the rims 15d a narrow strip 15e at an acute angle with the corresponding rim 15d.

These C-shaped elements 15 are so dimensioned that the distance L of their opening, between two rims 15d be greater than the width of one portion of the rear wall 15c.

When assembled for operation (Figure 3), the elements 15 form a filtering wall provided with inlet openings E and outlet openings S separated by a double inverted decreasing-increasing spiral.

The end elements 17 are portions of the center element 15. A labyrinth is thus defined which has vertical inlet slots E in communication with a channel spiralling along a decreasing diameter while retaining an approximately constant cross-section, then opening on a flow channel spiralling in the opposite direction along an increasing diameter while retaining an approximately constant cross-section, to reach eventually a vertical outlet slot S. Owing to their shape and size, the elements 15, 17 can be assembled an dismounted simply by moving them sideways and from the front rearward, without any vertical movement.

The filtering wall thus constructed from elements can be dismounted and provides spiralling passages having an inversion point at midway. This filtering wall 4 ends at its top with screens or supports 11 closing the space extending between the filtering wall 4 and the ceiling of the spray booth.

At the rear of the filtering wall 4, there is provided a conventional zigzag-shaped filter 21.

When the flow of gas charged with particles of paint and solvent travels through the filtering wall, a large proportion of the solid or liquid particles is trapped by the front walls

17 and 15a of the elements, runs along these sections and is collected in the base 6. Then, the flow of gas enters the spiral-shaped labyrinth via the slots O and practically all the particles - i.e. approximately from 99.4% to 99.6% of them - are deposited by centrifugation against the walls of the elements 15, 17 and flow by gravity into the collector base 6.

The remaining particles carried by the flow of gas exiting from the vertical outlet slots S are trapped by the zigzag-shaped filter 21. Owing to the design of the elements 15, 17, this cyclone separator can be dismounted very easily. One only needs to move the elements relatively to each other to disengage them. Thus, all these elements can be easily and rapidly dismounted for their cleaning if needed, and then reassembled.

For practical reasons relating to the manufacturing and assembling of the elements, their spirals are obviously square or polygonal when viewed in cross-section, but any other shape - circular, helicoidal, oval, etc. - can be envisaged. For obvious reasons, said spirals of each element extend over only approximately 270° to make possible their assembling and dismounting.

The main benefits and advantages of this cyclone separator are: 1. It can be dismounted and assembled without tools, fastening means, etc., which makes it possible to suspend the operation of the spray booth for only a very short time when cleaning. 2. The cyclone separator is assembled from elements which can be imbricated without joints. 3. Two types of elements only are used, center elements and side elements.

This is the first time that a cyclone separator can be assembled from prefabricated elements, simply by imbricating them.

Obviously, the separator elements are preferably made from folded metal sheet, but could be made from any other appropriate material. In another version, the paint booth can obviously be equipped only with a filtering wall 4, without the zigzag-shaped filter 21.

Figure 4 is a top view of a second embodiment of the filtering wall 4 consisting of two filtering walls according to the first embodiment, placed back-to-back and positioned so that the outlets S of the first wall coincide with the inlets E of the second wall 4. The efficiency of such a double wall is clearly superior to that of a single wall 4. In a third embodiment of the separator, the filtering wall 4 is not straight anymore, but is V-shaped or zigzag-shaped. This makes it possible to increase the filtering surface in a spray booth of a given length.

Further, in the embodiment illustrated, this filtering wall is designed in such a manner that two colors can be sprayed in the same booth.

To this end, at each rear intersection of two wall portions 4, there is provided a hinge mounted panel 30, the size of which corresponds to that of the wall portion 4 it can cover. This panel 30 is provided at its lower end with channels 31, 32 for collecting the paint from each one of its two faces. When the wall 4 comprises several adjoining V-shaped assemblies, each one is provided with a panel 30. Each panel 30 carries an arm 33 connected by an articulated link to an actuator rod 34 operated by a hydraulic cylinder 35.

As can be seen in Figure 7, the upstream angles of two wall portions 4, 4a are provided with a sheet 36 disposed along their bisecting plane and having bottom sections 37 with holes 38 extending therethrough, to allow the paint recovered to flow into the respective channels 31 and 32 of the movable wall 30 or into the collectors 6, 6a.

In operation, the panel 30 is pressed by the hydraulic cylinder 35 against for instance the section 4 of the filtering wall. Only the section or sections 4a of this filtering wall 4, 4a are operative. The paint is collected in the collector 6a and the channels 32, which can be connected for evacuating the paint collected. To use the same spray booth with a paint of another color, one only needs to move the panel or panels 30 to place them against the sections 4a of the filtering wall, in which case the part 4 of this wall becomes operative and the paint is collected in the containers 6 and the channels 31. The pivoting of the panels is quite fast, so that a spray booth equipped in this manner can switch practically without any loss of time from one paint to another, which is highly beneficial.

Claims

1. A cyclone separator for a flow of gas charged with solid or liquid particles comprising several passages of a generally spiralled shape, the direction of which is revered at midway, characterized in that it is comprised of at least two prismatic or cylindrical elements, exhibiting a generally C-shaped cross-section, forming at least one spiral, and in that these elements are imbricated inside each other, with their respective spirals extending in opposite directions over about 270°, to define a filtering wall, the front face of which has at least one inlet opening and the rear face of which has at least one outlet opening, these openings being connected by a part of an approximately constant cross section formed by a decreasing spiral followed by an increasing spiral, so that the elements can be introduced into each other without being moved lengthwise one relatively to the other.

2. A separator according to claim 1, characterized in that it comprises end elements formed with a single spiral.

3. A separator according to one of claims 1 or 2, characterized in that the center elements have a center wall connected at each of its ends to a spiral, the spirals being in opposite directions.

4. A separator according to one of the preceding claims, characterized in that the elements are comprised of straight parts oriented at right angles relatively to each other.

5. A separator according to one of the preceding claims, characterized in that the inner end of one of the spirals comprises a backwards folded portion or hook forming an acute angle with the last straight portion of said spiral.

6. A separator according to one of the preceding claims, characterized in that the rear face of the elements is pressed against crossbeams; these crossbeams carry positioning members for determining the relative position of the elements imbricated into each other.

7. A separator according to claim 6, characterized in that the elements have above them a screen closing the space extending between the elements of this latter row and the ceiling of a paint booth.

8. A separator according to one of claims 1 to 7, characterized in that the elements imbricated into each other can be separated by a simple relative transverse movement.

9. A separator according to one of the preceding claims, characterized in that the filtering wall is planar.

10. A separator according to one of claims 1 to 8, characterized in that the filtering wall exhibits straight sections disposed in a V-shaped or a zigzag-shaped arrangement.

11. A separator according to claim 10, characterized in that it comprises a panel hinged along a folding line of the filtering wall and having a size corresponding to the surface of a straight section of the filtering wall, this panel being capable of closing one or the other of two wall sections adjacent to said folding line.

12. A separator according to claim 11, characterized in that the lower section of the panel has on each side thereof a channel for collecting the paint.

13. A separator according to claim 10, characterized in that it comprises a panel hinged along a folding line of the filtering wall and having a size corresponding to the surface of a straight section of the filtering wall, and extending to a metal sheet disposed along the bisecting plane of two adjoining filtering wall sections, this panel being capable of closing one or the other wall sections adjacent to its hinged edge.