US2695681A - Dust filter - Google Patents

Description

Nov. 30, 1954 GAA. BoE-sGER 2,695,581

DUST FILTER Filed Aug. 2v, 1952 4 sheets-sheet 1 INVENTOR. G50/PGE ,4. 5055651? Nov. 30, 1954 G. A. BoEsGER 2,695,681

DUST FILTER Filed Aug. 27. 1952 Sheets-Sheet 2J IN VEN TOR. GEORGE ,4 .5055669 Nov 30, 1954 G. A. Bol-:sGl-:R

DUST FILTER 4 Sheets-Sheet 3 Filed Aug. 27, 1952 Fie.

INVENTOR.

Gao/PGE A 50e-565@ NOV. 30, 1954 G, A, BOESGER 2,695,681

DUST FILTER Filed Aug. 27. 1952 4 Sheets-Sheet 4 fie. 7

INVENTOR. 660,45 4. 50a-565A United States Patent uO DUST FILTER George A. Boesger, North Olmsted, Ohio, assignor to The W. W. Sly Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Application August 27, 1952, Serial No. 306,650

9 Claims. (Cl. 183-61) This invention relates to improvements in dust filters `for industrial use and has to do particularlyy with bag spacers for use in equipment of this kind in which the dust is filtered through bags made of natural or synthetic fabrics selected according to the character of the dust to be handled.

' When a conventional air filter of the character indi- Acated is in operation the fabric walls of each bag tend to be drawn together. Wire spacers are placed within the bags to counteract this tendency. When the operation of such a lter means is begun the fabric of the bags is forcibly slapped against the spacers and remains `in contact therewith, but experiences a certain amount of friction due to variations in the ow of air in the air stream. These actions tend to wear holes m the `fabric, especially at the joints in the spacer frames.`

In a recent development in the art, disclosed in my `Patent 2,583,039, and in the drawings of the present fabric.

The surfaces of the wire frames making up the spacers within the bags and the surfaces of the wire frames vmaking up the external spacers between bags are hard and unyielding and they are seldom completely smooth where the wires are welded together. Consequently when the direction of air flow is changed, as in my patented construction, the fabric of the bag is suddenly snapped in wardly or outwardly, causing it to `strike sharply against the wire spacers, producing wear.

One of the objects of the present invention therefore is the provision of spacers within the bags or spacers both within and between bags, as the case may be, which are provided with means for cushioning the4 force of the blow when the fabric strikes against them.

Another object is the accomplishment of such cushioning by the coating of the wires of each spacer with rubber or other soft, smooth, yielding material.

Another object is the provision of a dust filtering construction of the type in which dust is dislodged from the surfaces of the bags by periodic reversal of the direction of flow of air through the individual bags, wherein spacers are provided within the bags and between adjacent bags of a character such as to limit movement of the bag fabric when the direction of air flow is changed and thereby decrease the force of the blow as the fabric strikes against the internal or external spacers alternately.

Another object is the provision of a novelform of externalispacers between bags mounted in a novel manner,V

permitting quick and easy removal or` replacement.

A further object of the invention is the provision of novel means for providing an effective seal between the open ends of the cleaner bags and a traveller through which air is caused to ilow in a reverse direction for removing dust that has collected on those surfaces of the ICC seal the joint around a bag opening as the cushion passes over the wall.

Other objects and features of novelty will appear as I proceed with the description` of that embodiment of the invention which, for the purposes of `the present application, I have illustrated in the accompanying drawings in which Fig. 1 is a perspective view partly in section and partly broken away showing a portion of a three tier series of filters embodying the invention;

Fig. 2 is a horizontal sectional view through a dust filtering construction illustrating a means for progressively changing the direction of air flow through one bag at a time;

Fig. 3 is a horizontal sectional view corresponding to a portion of Fig. 2 but on a larger scale;

Fig. 4 is a vertical sectional view illustrating a means for subjecting the major portion of the dust wall to subatmospheric pressure for creating a normal flow of air through the dust collector for cleaning the air and means for causing air at atmospheric pressure to flow in a reverse direction through one bag at a time for cleaning the bags',

Fig. 5 is a fragmental vertical sectional view illustrating the internal and external spacers;

Fig. 6 is a further vertical sectional view on a still larger scale illustrating particularly the soft resilient coating applied to the spacers; and

Fig. 7 is a sectional view on a larger scale correspending to a portion of Fig. 2.

Referring first to Fig. l of the drawings, a bag is shown at 10 in the lowermost tier of the apparatus. In the intermediate tier a bag 10 is shown partly broken away in order to illustrate the internal spacer 11 which may be divided vertically into two sections meeting at the middle as shown. The internal spacer comprises vertical elements 12 and horizontal elements 13. Each of the vertical elements is made up of one or more wires forming a vertical loop, the plane of which is at right angles to the bag walls. Theside wires of each of these elements are crimped inwardly toward each other at intervals throughout the length of the element as indicated at 14, the crimps being welded together to increase strength. The various vertical elements are held in `spaced relation by horizontal wires 13 to which they are welded. The horizontal wires 13 at their ends may be bent around the endmost vertical elements, as indicated at` 15 in Fig. 3. The welds between wires 12 and 13 present unavoidably some surfaces which are rough and sharp rather than smooth.

In accordance with the invention there is employed between successive bags an external spacer of novel construction illustrated in the top tier of the dust collector of Fig. 1. This spacer comprises a horizontal supporting bar 16 and a series of spaced vertical wire elements 17 depending therefrom. These vertical elements are preferably although not necessarily staggered with respect to the vertical elements 12 of the internal spacers. As the internal spacers practically ll the bags and as the external spacers have a width dimension substantially equal to the spacing of the bags no ballooning of the fabric as a whole is permitted.

Each of the external spacers 17 is made up preferably of a single loop of wire having meeting crimps` 18 welded together at their meeting points. Eyes 19 are formed at the upper ends of the wire. These eyes 19 are positioned on opposite sides of the transverse supporting bar 16 in line with a perforation through the bar, and a rivet 20 is caused to extend through this perforation, the two eyes and two washers 21. The eyes 19 are in planes at right angles to the plane of the crimps 18, and being held firmly against the at sides of bar 16 they hold the spacer element with its main plane at right angles to the bag walls and prevent any tendency for the spacer to turn about a vertical axis.

All surfaces of the internal spacers 11 are covered `with a non-metallic soft yielding coating which may be natural or synthetic rubber or other suitable substance, this coating being indicated in Fig. 6 at 23 and 24. A similar coating 25 is applied to the external spacer. In this instance however the coating terminates below the eyes 19 as indicated in Fig. 6. The welds and other 'rough spots in the Wire frame of the internal spacer and the dependent elements of the external spacer are thus covered and all surfaces are rendered smooth and yielding. The bars 16 which support the external spacer elements are preferably mounted in slots formed in bars 26 at the front and rear of the assembly, the bars 26 being mounted rigidly upon or constituting part of the frame of the apparatus.

The bags are mounted and supported in amore or less conventional manner. In the rear of each bag there is a vertically disposed bar 30 of triangular cross section having one or more rearwardly extending hooks 31 which may be connected with the frame of the machine at the rear thereof through the intermediacy of tensile springs. The bar 30 is rst put into the bag. Then the hooks 31 projecting through the bag are attached to the spring fastenings, after which the bag is pulled forward toward the front of the machine. Vertical bars 32, similar in cross section to the bars 30 are mounted at the front of the machine frame. series of forwardly projecting pins 33. The fabric at one vside of one bag is threaded over the pins of a bar and the :fabric onone side of the adjacent bag is threaded over the same pins, the two liaps thus overlapping. Then a rubber slab 35 is mounted upon the pins and held in .position by suitable means, as for example by metallic grid elements 36 suitably mounted in the frame and having rounded forward edges. These grid elements 36 together constitute the dust wall. end of each bag has been secured in place over the pins 33, the bag is put under tension by adjusting the spring fastenings attached to hooks 31. Thereafter the internal spacers are slipped into the bags.

As previously stated the present invention is herein illustrated as applied to a type of apparatus in which the bags are cleaned one at a time by reversing the direc tion of air flow. The direction of normal ilow of air is from the rear to the front of the machine or from the right to the left in Figs. 2 and 3. Suction is created in the clean air chamber 40, Fig. 2, by a blower 41, the discharge from which is shown as an upstanding pipe 42 4in Figs. 2 and 4. A fitting 45 extends through the front wall of the clean air chamber 40, and from this fitting a flexible conductor 46 leads to a traveller 47 that comprises a pair of spaced vertical angle irons 48 which ex- `tend from top to bottom of the clean air chamber. At their ends these angle irons are attached by means of adjustable bolts 49 to a second pair of vertical angle irons 50.` The latter angle irons are attached at their opposite ends to top and bottom plates 51 upon which are secured stub shafts that carry flanged rollers 52 which run upon top and bottom tracks 53 that extend entirely across the machine. A cable 54 has its ends mounted in Athe traveller 47. Its intermediate portions run over sheaves 55 and 56 at the sides of the machine.. An ,electric motor 57 turns sheave 5S to move the traveller 47 to one side of the machine whereupon a switch, not shown, reverses the direction of rotation of the motor and causes the traveller to move to the opposite side of the machine. This arrangement is disclosed somewhat more in detail in my Patent No. 2,583,039 dated Ianuary 22, 1952.

A metal plate 60, substantially coextensive with the height of the traveller, extends across and bears against angle irons 48 with side flanges 70 engaging the outer surfaces of the angle irons. Forward of this plate there is a cushion made up of a series of belting slabs 6l, a block of sponge rubber 66 and a sheet of soft rubber 467. The belting'is vulcanized to the sponge rubber7 as is also the rubber sheet 67.

Pins 65 are tted tightly within holes in plate 60 spaced at regular intervals throughout the height of the plate and disposed near the side edges thereof. Correspondingly positioned holes in the belting 61 receive these pins snugly, and thus the cushion is held against lateral displacement.

The side edges of the rubber sheeting 67 are made Wide enough to enclose` the sides of the cushion and extend beyond it along the outer surfaces of the flanges 70. Bolts 71 extending through the angle irons 48, the flanges 70, the rubber sheeting 67 and reenforcing strips 72 hold tle cushion, including its supporting plate 60, firmly in p ace.

1 I have found that belting of a thickness of vone-fourth Each of these bars 32 carries a When the open front 4 inch and sponge rubber of a thickness of one and threefourths inches is satisfactory. f

ln the operation of the machine the traveller must be caused to bear rather heavily against the dust wall grid elements 36 in order to maintain an effective seal. This is due in part to the fact that the pressure differential as between the plate 60 and the forward side of the sponge rubber block tends to draw the traveller away from the dust Wall, and the bolts 49 must overcome this force in addition to .pressing the traveller against the dustwall with sufficient force to maintain the seal.

The movement of the traveller crosswise ofthe elements 36 tends to wrench the cushion from the metal plate 60, but the belting layer 61, forming the base of the cushion, is held securely to the metal plate by the pins 65 and bolts 71 and hence the cushion cannot be dislodged by the movement of the traveller.

There is a vertical slot 63 through plate 60, belting 61 and rubber block 66. Spaced holes 68 through the rubber sheet 67 register with the slot 63. This slot and these holes extend throughout the full vertical dimension of the openings in the bags 10. These openings are of substantially the same width as the slots 63.

The bolts 49 are so adjusted that the cushion seal consisting of sponge rubber block 66 and rubber sheet 67, is forced rmly against the grid elements 36 so that the opening at the forward end of each bag 10 is sealed along both vertical edges. The cushion sea-l bears also against horizontal frame elements, not shown, at the top and bottom of the bag openings, whereby each opening covered by the cushion is sealed throughout its perimeter. The traveller 47 in moving back and forth across the machine atl a-relatively slow rate of speed causes the slot 63to register with one bag opening after another, while certain of the bags on either side of the slot are blocked off from the action of the sub-atmospheric pressure in the clean air chamber and constitute more or less dead air spaces.

The traveller 47 comprises a metallic housing 64 with which is connected the ilexible hose 46 and by which atmospheric air is drawn into the housing 46 and through the slot 63 into the bag being cleaned, the sub-atmospheric lpressure in the dust chamber constituting the impelling force. In other words the single blower 41 serves to effect the `air cleaning function of the machine by drawing air through the major number of bags into the clean air chamber and at the same time to effect the bag cleaning function by drawing atmospheric air into the dust cham- 'ber through the bag being cleaned.

The operation of the machine will be obvious from the foregoing description of its construction. Each time slot 63 comes into register with the open end of a bag the direction of air ilow inside the bag is reversed and the fabric tends to balloon outwardly. The external spacers 17 limit this ballooning tendency to relatively narrow vertical strips between adjacent spacers. The resulting movement of the fabric is thus restricted, but also the soft coating on the spacers 17 cushions such movement as occurs and presents smooth surfaces where the fabric strikes it. Wear is thereby greatly diminished. Similarly when the traveller 47 passes beyond the cleaned bag, thereby exposing its open end to the'suction in clean air chamber 40, the side walls of the bag are suddenly drawn inwardly against the coated wires 12 and 13 of the internal spacer. This movement of the fabric is also cushioned by the coating on the Wires, and the welds and other roughspots are smoothed out by the same means. Thus the wear which would' otherwise result from the snapping back and forth of the bag fabric is largely eliminated.

Having thus described my invention, I claim:

l. In a dust filter of the type in which clean air is .caused to ow reverselythrough the lter screens periodically for dislodging dust adhering thereto, a series of bags disposed in parallel spaced relation, means for causing dust laden air to flow normally from the outside to the inside of each bag toward ,a clean air discharge, whereby the dust is deposited onf/the external surfaces of the bag, an internal spacing means for each bag comprising a wire frame adapted to twithin the bag and prevent collapse thereof during the normal filtering operation, external spacing means between bags comprising wire elements to hold thebag walls against ballooning out- Wardly when the direction of air flow therethrough is reversed, said external spacing means between adjacent bags comprising a series of independent spaced vertical elements supported at their upper ends and held thereby against movement about a vertical axis, each of said elements having side members disposed relative to each other in a plane at right angles to the bag walls, said side members of each element meeting and secured together at intervals throughout the length of the element.

2. A dust filter construction as defined in claim 1, comprising a coating of smooth soft yielding material on said internal and external spacing means providing smooth yielding contact points for the bag fabric as it strikes said external and internal spacers alternately upon change of direction of air flow through the bags.

3. In a dust filter of the type in which air is caused to ow reversely through the filter screens periodically for dislodging dust adhering thereto, a series of bags disposed in parallel spaced relation, means for causing dust laden air to ow normally from the outside to the inside of each bag toward a clean air discharge, whereby the dust is deposited on the external surfaces of the bag, external spacing means between bags comprising wire elements to hold the bag walls against ballooning outwardly when the direction of air ow therethrough is reversed, and a coating of smooth non-metallic yielding material on said external spacing means providing smooth yielding contact points for the bag fabric as it strikes said external spacers upon the reverse flow of air through the bags, wherein said external spacing means between adjacent bags; comprises a series of independent spaced vertical elements supported at their upper ends, each of said elements having side members disposed relative to each other in a plane at right angles to the bag walls, said side members of each element meeting and secured together at intervals throughout the length of the element.

4. In a dust filter of the type in which air is caused to flow reversely through the filter screens periodically for dislodging dust adhering thereto, a series of bags disposed in parallel spaced relation, means for causing dust laden air to fiow normally from the outside to the inside of each bag toward `a clean air discharge, whereby the dust is deposited on the external surfaces of the bag, an internal spacing means for each bag comprising a wire frame adaptedto fit within the bag and prevent collapse thereof during the normal filtering operation, external spacing means between bags comprising wire elements to hold the bag walls against ballooning outwardly when the direction of air fiow therethrough is reversed, and a coatingof smooth non-metallic yielding material on said internal and external spacing means providing smooth yielding contact points for the bag fabric as it strikes said external and internal spacers alternately upon change of direction of air flow through the bags wherein the internal spacers include vertical elements which are staggered with respect to the vertical elements of the external spacers, whereby restricted movement of the bag walls is permitted upon change of direction of air ow. 5. In a dust filter of the type embodying bags disposed in parallel relation, an external spacer between bags comprising a flat supporting bar, means for removably mounting the bar on edge, and vertically disposed depending Wire spacer elements mounted at intervals along the length of the bar, each of said elements consisting of a single wire loop with its ends at the top, said ends terminating in eyes attached to said bar and held firmly against its opposite sides, the maior portions of said loops being disposed in planes at right angles to the plane of said fiat bar and the loops having at intervals inwardly directed meeting crimps welded together at their meeting oints. p 6. In a dust filter, a dust chamber, a clean air chamber, a series of parallelly disposed bag screens in said dust chamber, a dust wall between said chambers comprising parallel metal grids and end members defining forward openings for the bags, a traveller movable across said dust wall having a slot therethrough adapted to register with the open ends of the bags one after another, means for creating sub-atmospheric pressure in the dust chamber, flexible means for conducting air at atmospheric pressure to said traveller arid to the slot therethrough effective throughout the movements of the traveller across said dust wall, said traveller comprising an elongated sponge rubber cushion bearing upon said dust wall over a plurality of bag openings, and means for pressing said traveller against said dust wall during its movement thereover, whereby the sponge rubber cushion is cornpressed around each of said plurality of bag openings for sealing the same.

7. A dust filter as defined in claim 6, wherein said dust bags and dust wall are arranged approximately vertical, said filter comprising top and bottom transverse rails in said clean air chamber, top and bottom carriage members, flanged rollers on said carriage members running on said tracks, and means on said carriage members for supporting said cushion and adjustably pressing it against said dust wall.

8. In a dust filter, a dust chamber, a clean air chamber, a series of parallelly disposed bag screens in said dust chamber, a dust wall between said chambers comprising parallel metal grids and end members defining forward openings for the bags, a traveller movable across said dust wall having a slot therethrough adapted to register with the open ends of the bags one after another, means for creatingsub-atmospheric pressure in the dust chamber, fiexible means for conducting air at a pressure no less than atmospheric pressure to said traveller and to the slot therethrough effective throughout the movements of the traveller across said dust wall, said traveller comprising a metal plate, a non-metallic slab firmly joined to the forward side of said plate, a cushion firmly joined to the forward surface of said slab comprising a sponge rubber block, and means on said traveller for pressing said cushion against said dust wall during movement of the traveller thereover, whereby the cushion is compressed around each of said plurality of bag openings for sealing the same.

9. In a dust filter, a dust chamber, a clean air chamber, a series of parallelly disposed bag screens in said dust chamber, a dust wall between said chambers comprising parallel metal grids and end members defining forward openings for the bags, a traveller in said clean air chamber movable across said dust wall, means for creating subatmospheric pressure in the dust chamber, said traveller comprising an elongated sponge rubber block bearing upon said dust Wall over a plurality of bag openings, said block being continuous except for a slot extending through the block from front to rear of a width substantially the same as the width of a bag, means for conducting air at a pressure no less than atmospheric pressure to said traveller and to the slot therethrough effective throughout the movements of the traveller across said wall, and means for pressing said traveller against said dust wall during its movement thereover, whereby the sponge rubber block is compressed around each of said plurality of bag openings for sealing the same.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,818,736 Moore Aug. 11, 1931 1,868,876 Boesger July 26, 1932 2,072,906 Rosenberger Mar. 9, 1937 2,507,335 Donohue May 9, 1950 2,583,039 Boesger lian. 22, 1952 2,607,437 Crawford et a1. Aug. 19, 1952

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