US3606739A - Air filter - Google Patents

Abstract

AN AIR FILTER COMPRISING A HOUSING HAVING A REMOVABLE LID AND AN INLET OPENING AND AN OUTLET OPENING. A UNITARY FILTERING MEDIUM COMPRISING A SINGLE LENGTH OF MATERIAL FORMED INTO A PLURALITY OF INDIVIDUAL BAGS IS SUPPORTED WITHIN THE HOUSING OF THE FILTER BETWEEN THE INLET OPENING AND THE OUTLET OPENING. THE UNITARY FILTERING MEDIUM IS SECURED TO AND SUPPORTED BY AN INTEGRAL FRAME MEMBER WHICH IS, IN TURN, SUPPORTED BY PORTIONS OF THE HOUSING AND MAINTAINED IN POSITION WITHIN THE HOUSING BY THE COOPERATIVE ARRANGEMENT OF THE LID OF THE HOUSING AND MEMBERS DISPOSED BETWEEN THE LID AND PERIPHERAL PORTIONS OF THE FRAME MEMBER.

Description

D. A. PETERSON sept. 21, 1971 AIR FILTER Filed July 1o, 1969 2 Sheets-Sheet 1 FIG.

FIG. 4.

/NVEN TOR. DONALD A. PETERSON By l A f forneys D. A. PETERSON AIR FILTER sept. 21,v 1971 2 Sheets-Sheet I Filed July 1Q. 1969 omvALa A. Ps rsRsoN A f farneys 3,606,739 Patented Sept. 2l, 1971 3,606,739 AIR FILTER Donald A. Peterson, 5616 Koeffler Drive, Pittsburgh, Pa. 15236 Filed July 10, 1969, Ser. No. 840,733 Int. Cl. B01d 46/02 U.S. Cl. 55-484 8 Claims ABSTRACT OF THE DISCLOSURE An air filter comprising a housing having a removable lid and an inlet opening and an outlet opening. A unitary filtering medium comprising a single length of material formed into a plurality of individual bags is supported within the housing of the filter between the inlet opening and the outlet opening. The unitary filtering medium is secured to and supported by an integral frame member which is, in turn, supported by portions of the housing and maintained in position within the housing by the cooperative arrangement of the lid of the housing and members disposed between the lid and peripheral portions of the frame member.

BACKGROUND OF THE INVENTION (1) Field of the invention discharge through an outlet opening to the surrounding atmosphere.

(2) Description of the prior art In the past, the filters with which the present invention relates have been constructed of a housing having an inlet opening and an outlet opening. A filtering medium consisting of a plurality of discrete individual bags were placed between the inlet opening and outlet opening with the surfaces of each bag providing filtering areas. Each discrete bag comprised a strip of material of flannel, for example, folded upon itself with its edges joined together to form a bag having an open top and closed bottom. A rigid steel band' encircling the bag at the top portion thereof was provided and a portion of the top of the bag was folded over to form a cuff which was secured to the rigid steel band. A section of mesh screen was placed within the bag for stiffening it, and a weight was provided in the bag to maintain the bag in a substantially vertical position Within the housing of the filter.

In order to support these discrete bags within the housing, a flange or ledge was provided within the housing between the inlet and outlet openings. The discrete bags were placed within the housing with the rigid steel bands at the tops of the bags resting on the ledge. No problem was encountered in placing the initial bags on the ledge, however, as the last of these bags was to be placed on the ledge, great difficulty arose due to the rigidity of the steel band.

As is evident to those skilled in the art, in order to provide an efiicient fil-tering medium between the inlet opening and outlet opening, the discrete bags must be in contact with one another at their top portions, and the portions of the bags adjacent the housing must be in contact therewith. Otherwise, the particle laden air stream will pass between adjacent bags and between the housing and bags in an unfiltered state, thereby defeating the purpose of the filter. Accordingly, to prevent air leakage and because the filtering medium consists of a plurality of discrete bags which are maintained in contact with each other at their top portions solely by the Walls of the housing, the last few bags must be stuffed into the housing. The rigid steel band at the tops of the bags renders this stuffing burdensome and time consuming. This problem of stuffing the last of the bags into the housing occurs in the filters initial construction and subsequently upon the replacement of the filtering medium of the filter.

SUMMARY OF THE INVENTION iBriefiy, the present invention is directed to a filter comprising a housing having a removable lid and an inlet opening and an outlet opening. A filtering medium comprising a single length of material formed into a plurality of individual bags is provided within the housing, A cuff portion which encircles the single length of material is provided for securing it to an integral frame. A support means is associated with the housing which is adapted to be engaged by the frame member for supporting the single length of material between the inlet opening and outlet opening. Finally, means are provided which are cooperatively arranged in surrounding relation to the cuff portion and disposed between the undersurface of the lid of the housing and peripheral portions of the frame member for maintaining the frame member in position between the inlet and outlet openings and in engagement with the support means.

The present invention, therefore, provides a single length of material formed into a plurality of individual bags which present a number of filtering surfaces to the air to be filtered and Which are secured to an integral frame. The integral frame supports the filtering medium within the housing and permits the unitary filtering medium to be easily inserted into the filters housing, thereby eliminating the need of stuliing the individual bags into the housing of the filter Accordingly, a primary object of the present invention is to provide a filter having a unitary filtering medium consisting of a plurality of individual bags linked together which obviates the need for stuffing the individual bags within the housing of the filter.

Another object of the invention is to provide a filter including a unitary filtering medium- Which may be easily removed and replaced, thereby facilitating the changing of the filtering medium of the filter.

Still another object of the invention is to provide means cooperatively arranged 'between the lid of the housing and peripheral portions of the integral frame member for maintaining the frame member, and thus the unitary filtering medium, in position within the housing.

These and other objects of the invention will become apparent from Vthe following detailed description taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional elevation of the filter of the present invention, with some of the parts being broken away;

FIG. 2 is a partial perspective yview of the filter of the present invention with one of the sides thereof removed and parts broken away to further illustrate the interior of the filter;

FIG. 3 is a plan View of a portion of the strip of material from which the unitary filtering medium of the present invention is fashioned;

FIG. 4 is a fragmentary view in section showing details of the unitary filtering medium of the present invention as secured to the frame member; and

FIG. is a perspective view of the frame member of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings and particularly to FIG. 1, a filter is shown generally at 10. The filter comprises a rectangular box or housing 12 having a removable top or lid 14 which is received by a ange or seat portion 16 which extends laterally outwardly adjacent the top edges of the walls of housing 12. A seal 18 is provided between seat portion 16 and lid 14 to prevent the leakage of air between them. Lid 14 is secured to seat 16 by a plurality of threaded bolts such as those shown at 20 and 22. An air inlet opening 24 is provided in side wall of housing 12 through which a particle laden air stream is drawn into the filter 10. The particle laden air stream introduced into housing 12 through air inlet opening 24 is caused to pass through a unitary 4filtering medium shown generally at 26. After passing through unitary filtering medium 26 which traps the particles contained therein, the now filtered air stream is discharged through air outlet opening 28 provided in the side wall 29 of housing 12.

The unitary filtering medium 26 comprises of a plurality of bags 30 which are integrally linked together. The bags 30 are fashioned from a single strip of material such as that shown generally at 32 (FIG. 3). The strip of material 32 consists of a continuous strip of flannel, for example, and is provided with outwardly extending opposite tabs 34 positioned along its length. Only a portion of strip 32 has been shown which represents the first three bags 30 of the left side of filtering medium 26 as viewed in FIGS. 1 and 2. The strip of material is creased or folded along the lines indicated in FIG. 3 to fold like an accordion. The folding along the lines indicated results in an accordion strip of material having a plurality of pairs of adjacent sections 36, 38; 40, 42; 44, 46 (see first three bags 30 of the left side of unitary filtering element 26 in FIG. l). Selected pairs of the adjacent sections are joined together, thereby forming the bags 30. For instance, section 36 Iwhen folded as above indicated overlies section 38 with the tab portion 34 of section 36 overlying the tab portion 34 of section 38. The overlying sections 36, 38 are sewn together along their `opposite edges as indicated by the dotted lines 48 and 50. Tabs 34 of adjacent sections 36, 38 are also sewn together, the bottom portion 52 of tab portion 34 associated with section 36 being sewn to the top portion 54 of tab portion 34 associated with section 38. Likewise, section when folded as above indicated overlies section 42 with the tab portion 34 of section 40 over* lying the tab portion 34 of the portion 42. These overlying sections 40, 42 are also sewn together along their opposite edges as indicated by the dotted lines 56, 58. The tabs 34 of these adjacent sections 40, 42 are also sewn together, the bottom portion of the tab portion 34 associated with section 40 being sewn to the top portion 62 of tab portion 34 associated with section 42.

It will be noted that adjacent sections of the strip of material 32 each share one-half of the tab portion 34 associated therewith when the adjacent sections are joined together. The remainder of bags 30 contained in the unitary filtering medium 26 are fashioned in a like manner. After the joining of selected pairs of the adjacent sections together in the manner indicated, the bags 30 are turned inside out, thereby forming the unitary ltering medium 26. The resulting unitary lfiltering medium 26 has a lip portion extending upwardly above the open tops of the bags 30 which encircles the bags 30 taken as a whole. This lip portion results from the joining of the bags 30 together in the manner indicated and the subsequent turning of the bags 30 inside out. This lip portion is then folded over to form a cuff 64 (see FIGS. 1, 2 and 4) which ex- 4 tends around the unitary filtering medium 26 at the top thereof; and its purpose is to secure the ltering medium 26 to an integral rectangular frame member 66 of L- shaped cross section (see FIG. 5).

In its folded position, lip or cuff 64 has the tab portions 34 of the strip of material 32 facing outwardly as indicated in FIGS. 1 and 2 generally at 65 and 67, respectively. Each half of the tab portions 34 extends along the length of the strip of. material 32 that has been joined to another half of an adjacent tab 34 and is opened and folded flat as indicated at 69 and 71a. Prior to folding the lip portion or cuff 64, a sealing band 68 of felt, for example, is affixed to the cuff 64 for aiding in sealing the unitary filtering medium 26 to the frame member 66.

As best seen in FIG. 5, frame member 66 comprises a rectangular member having a first pair of opposite sides extending along the width of the unitary filtering medium 26. The rear side 70 of this first pair of opposite sides is shown in FIG. 5; and the front side '71 is shown in FIGS. l and 2. A second pair of opposite sides 72 and 74 extend along the length of the unitary -ltering medium 26. A plurality of cross members 76 span between the first pair of opposite sides 70, 71 and are parallel to the sides 72 and 74. Each of the first pair of opposites sides 70, 71 and each of the second pair of opposite sides 72, 74 have an L- shaped cross section. For example, sides 72 and 74 consists of vertical portion 78 and 80, respectively, and horizontal portions 82 and 84, respectively.

In assembling the unitary filtering medium, the bags 30 are positioned between the spanning members 76 with the integral portions 86 linking the bags 30- together supported by the spanning members 76. As was stated above, the lip or cuff portion 64 is secured to the frame member 66. The cuff portion 64 together with the band 68 are positioned in overlapping relation to the vertical portions of the sides making up the frame member 66 and are glued or stapled to these vertical portions. The unitary filtering medium 26 is accordingly supported by the frame member 66 along the length thereof and across the width thereof by the sides 70, 71, 72 and 74. In this respect, the cu portion is folded over the top and vertical portions of the sides making up the frame member in a generally inverted U-shaped configuration.

In order to stiffen and maintain the adjacent sections of the bags 30 apart, a U-shaped wire screen 87 is positioned within adjacent pairs of the bags 30. This screen also serves as a spacer to maintain the opposite side walls of each bag separated. Also, to maintain the bags 30 in a substantially vertical position within the housing 12, a veight member 88 is placed in the bottoms of the bags To further secure the unitary filtering medium 26 to the integral frame member 66, a pair of first strip members 90 and 92, respectively, and a pair of second strip members 94 and 96, respectively, are provided which are arranged in substantially surrounding relation to the cuff portion 64. The members 90 and 92 extend along the width of the filtering medium 26 with member 90 being secured to the vertical portion of side 71 and with member 92 being secured to the vertical portion of side 70. Preferably, the members 90 and 92 are secured to the vertical portions of the sides 7tly and 71 as by fastening elements such as screws (not shown) which pass through the cuff portion 64.

The members 94 and 96 extend along the length of the filtering medium 26 with member 94 being secured to the vertical portion of side 72 and with member 96 being secured to the vertical portion of side 74. The members 94 and 96 are also preferably secured to the vertical portions of the sides 72, 74 as by screws 100 which pass through the cuff portion 64.

In addition to aiding in the securement of the cuff portion 64 to the vertical portions of the frame member 66, the members 90, 92, 94 and 96 serve another function as will appear more fully hereinafter.

A flange means or seat portion 102, spaced from and located below the top of the housing 12, is provided around the inside of the walls of the housing 12 for supporting frame member 66 within housing 12. The horizontal portions of the sides making up frame member 66 are received on the seat portion 102 when the frame member together with its associated parts is inserted into the housing 12. A flexible seal 104 is provided between seat portion 102 and the horizontal portions of the sides 70, 71, 72 and 74 to prevent leakage of air between them. Preferably, the seal 104 is glued, for example, to the undersurfaces of the horizontal portions of the frame member 66 and forms a part thereof.

It will be noted that the lower edge portions of each of the members 90, 92, 94 and 96 are in abutment with the upper surfaces of the horizontal portions of the frame member 66 and that the upper edges of the members 90 and 92 are in abutment throughout their lengths with the undersurface of the lid 14 when the lid 14 is secured to the housing 12. It will be also noted that the members 94 and 96 each has a centrally disposed upstauding portion 106 and 108, respectively, extending from the upper edges thereof which are also in abutment with the undersurface of the lid 14 when the lid is secured to the housing 12. A centrally disposed cross member 109 is positioned between the portions 106 and 108 and is secured to these latter portions at its opposite ends as by screws. The undersurface of cross member 109 is in abutment with the uppermost surfaces of filtering medium 26 which it overlies and the upper surface of member 109 is in abutment with lid 14 when the lid 14 is secured to housing 12.

The Vertical dimensions of the members 90, 92 and the vertical dimensions of the portions 94 and 96 at the upstanding central portions 106 and 108, respectively, are chosen such that the upper terminal edges or portions of these members and the upper surface of cross member 109, lie in a horizontal plane disposed above the top of the cuff portion 64. The vertical dimension of the ilexible seal 104 is chosen such that, when the frame member 66 together with its associated parts is positioned on the flange means 102 and prior to the lid 14 being secured to the housing 12, the horizontal plane in which the upper terminal edges of the members 90-96 lie is disposed above the top edges of the housing 12. Accordingly, when the lid 14 is secured to the housing 12, the frame member 66 is forced downwardly into the housing compressing flexible seal 104 to assure a positive air tight seal between the flange means 102 and the horizontal portions of the frame member 66. Also, by reason of this arrangement, the frame member 66 is maintained in position on the flange means 102 between the air inlet and outlet openings 24 and 28, respectively.

With the unitary filtering medium 26 and integral frame member 66 together with its associated parts positioned within the housing 12 as indicated, the housing 12 is divided into two compartments 110 and 112. The particle laden air stream entering compartment 112 must pass through the unitary filtering medium 26 to compartment 110. From compartment 110, the air stream exits through outlet 28. Leakage of air between the unitary filtering medium 26 and the integral frame 66 is prevented by the cuff portion 64 together with its sealing band I68 being held positively in contact with the vertical portions of the frame 66 by the members 92-96. Leakage of air between the frame member 66 and seat portion 102 is prevented by the seal 104. Accordingly, the construction and the arrangement of the parts of the present invention provide a filter wherein the particle laden air stream cannot pass between the adjacent bags or between the bags and the housing in an unfiltered state as was possible when individual discrete bags made up the filtering medium of the filter. Because the bags 30 making up the filtering medium of the present invention are linked together and are secured to frame member 66 as a unit, the need of stuffing discrete bags into the housing is thereby eliminated. Furthermore, because of the arrangement of the members 90-96 in substantially surrounding relation to the cuff portion 64 and their being disposed between the undersurface of the lid 14 and the peripheral portions of the frame member 66, as indicated above, the frame member is maintained in engagement with the flange means 102 without the need of screws or other type fasteners thereby greatly facilitating insertion and removal of the filter medium from the housing 12. While the members 90-96 have been illustrated and described as being secured to the frame member 66, it will be evident that these members may be secured to the undersurface of the lid 14 and form an integral part thereof.

An important aspect of the invention is that the integral frame member 66 and the members 9096 are -preferably constructed of wood rather than heavy metal stock as was the case in prior filter constructions of this type. This wooden construction permits ready assembly of the filter, which assembly is accomplished merely by the drilling of holes in the members 90-96 at the required locations and thereafter securing the various associated parts with screws as above described. The screws will easily pass through the cuff portion 64 and be received in the vertical portions of the frame member 66 without the necessity of previously drilling holes in the vertical portions of the frame member. Accordingly, the need for a rigid steel band encircling the cuff portion 64 to secure the unitary filtering medium to the frame member 66 is no longer required as in prior constructions of filters of the type with which the present invention is concerned.

By reason of the wooden construction of the frame member 66 and members 90-96, there is thus provided by the present invention a relatively inexpensive, light weight disposable filter which is easily assembled in its initial fabrication and one which is easily inserted and removed from the housing in which it is designed to be used.

Although the invention has` been shown in connection with certain Specific embodiments, it will be readily apparent to those skilled in the art that various changes in form and arrangement of parts may be made to suit requirements without departing from the spirit and scope of the invention.

I claim:

1. In a filter comprising an enclosed housing having side walls, a bottom wall and a removable lid, a generally rectangular flange projecting inwardly from the side walls of said lhousing beneath said lid and lying in a plane extending generally parallel to said lid, an inlet opening in said housing beneath said flange, an outlet opening above said flange, and a bag filter supported on said flange and interposed between said inlet and outlet openings; the improvement in said filter comprising:

a generally rectangular frame member seated on said flange and extending across the housing,

a plurality of spaced straight parallel spanning cross members extending between two of the opposite sides of said frame member,

a plurality of parallel hanging filter bags formed from a sheet of filtering material and disposed side-by-side with their open ends connected to one another by portions of said sheet of filtering material which overlie said spanning members whereby said filter bags hang downwardly between adjacent ones of said spanning members with the outer bags hanging downwardly between a spanning member and a side of the frame,

a cuff portion extending around the top of said filter and connecting the upper edge of said bag filter to said frame member,

said frame member having a lower horizontal surface resting on said flange and an upper horizontal surface formed by opposed vertical walls with said upper horizontal surface and vertical walls extending around said frame member,

said cuff portionbeing wrapped around said vertical Walls and said upper horizontal surface to form a generally inverted U-shaped cross-sectional configuration with one outer leg of the U-shaped configuration terminating at the lower edges of said lvertical walls which face the walls of said enclosed housing,

strip members extending along and in abutment andv surrounding relation with the sides of said one outer leg of the U-shaped cross-sectional configuration of v said cuff portion, fastening elements passing through said strip members and said cuff portion and extending into said vertical walls of the frame member facing the walls of the enclosed housing to hold said cuff portion in place on said frame member, and

means in abutment with said lid for holding said frame member in abutment With said flange.

'2. The improvement of claim 1 wherein said frame member has a generally L-shaped crosss-sectional configuration with vertical leg portions and horizontal leg portions which extend toward the walls of the enclosed housing, said upper horizontal surface and vertical walls being on said vertical leg portion.

3. The improvement of claim 1 wherein said strip members each have an upper edge in abutment with the undersurface of said lid and a lower edge in abutment with a surface of said frame member, whereby the frame mem ber is held in snug abutting relationship with said flange when said lid is secured to the top of said enclosed housing.

4. The improvement of claim 1 including a flexible sealing means disposed between the lower horizontal surface of said frame member and said flange.

5. The improvement of claim 1 including a plurality of `wire mesh screens disposed within said plurality of filter bags to stiffen the same.

6. The improvement of claim 1 wherein said frame member and said strip members are formed from wood 8 and wherein said fastening elements comprise screws which extend through openings in said strip members and are screwed into a vertical wall of the frame member.

7. The improvement of claim 1 including a strip of sealing material interposed between said one leg of the U-shaped configuration and said one of the vertical walls facing the wall of said enclosed housing.

8. The improvement of claim 1 wherein two of said strip members on opposite sides of said frame member are of constant height and are interposed between said lid and said frame member to hold the frame member in snug abutting relationship with said flange, the other two of said strip members on the other two opposite sides of said frame member having raised central portions which abut said lid member to hold said latter-mentioned strip members in snug abutting relationship with said frame member and force it against said flange, and a centrally disposed cross member positioned between and connected to said raised central portions.

References Cited UNITED STATES PATENTS 3,249,228 5/ 1966 Arvanitakis 210-346 2,080,154 5/ 1937 Strindberg 55-500 2,640,560 6/1953 Lewis et al 55--341 2,907,406 10/1959 Baden et al 55-341 3,160,908 12/1964 Peabody et al 55-341 3,273,321 9/1966 Bauder et al. 55-341 3,368,331 2/1968 Baxendale 55-341 3,394,534 7/1968 Andrews et al 554-484 3,484,889 12/1969 McCandless 55-305 FRANK W. LUTIER, Primary Examiner B. NOZICK, Assistant Examiner U.S. Cl. X.R. 55-49l, 500, 521

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