GB1588578A

GB1588578A - Pleated paper filter cartridge

Info

Publication number: GB1588578A
Application number: GB19489/78A
Authority: GB
Original assignee: Donaldson Co Inc
Current assignee: Donaldson Co Inc
Priority date: 1977-05-16
Filing date: 1978-05-15
Publication date: 1981-04-23
Also published as: JPS5416784A; ZA782757B; AU3587478A; FR2390986B1; JPS595006B2; FR2390986A1; CA1089777A; BR7802921A; DE2819177C2; AU510250B2; DE2819177A1

Description

(54) PLEATED PAPER FILTER CARTRIDGE 1(7at We, DONALDSON COMPANY, INC., a Corporation organised under the laws of the State of Delaware, United States of America of 1400 West 94th Street, Min neapolls, Minnesota 55431, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be plarticularly descrilbed in and by the following statement: This invention relates to filters and to air cleaners containing them. In particular it relates to filters which can be used in a known system for cleaning the air admitted to diesel locomotive engines. This system comprises a housing having an outlet for connection to the engine inlet, and a panel with a plurality of rectangular inlet openings, into which bagshaped "cartridges" of glass-fiber filter fabric are inserted, being secured by clamping outturned lips of the bags to the face of the housing. The clamping member includes an open wire skeleton frame or cage for holding the walls of the bag apart to give a maximized working surface and to protect against turbosurge. The fabric is coated with an oil adhesive to assist in trapping particulate matter.

While this system has been quite successful, the filter medium is initially of relatively low efficiency, and its efficiency decreases further as the oil adhesive takes up air contaminants.

The necessity for the internal cage means that the system must be installed with sufficient space around it to permit removal and replacement of this element, and also results in wear on the inner surface of the bag.

The object of the present invention is to provide a filter suitable for use in the air cleaner system referred to above and which is a self-supporting structure.

Accordingly, a first aspect of the invention is a filter comprising a body of pleated paper, said body having a U-shaped cross-section in a plane transverse to the fold lines of the pleats; two closure members secured respectively to the two edges of said body at the ends of the pleats to form with said body a hollow pocket; and an elongated rectangular frame secured to said body and defining the mouth of the pocket; wherein each of said closure members is resilient in its own plane whereby the filter can be bent about axes parallel to the pleats.

In its preferred form the filter comprises a flexible, integral filter which can be distorted for successful insertion into the air cleaner system housing from spaces shorter than the behind-the-panel length of the filter. It is inherently shape-retaining so that no inner form or skeleton is necessary, and it makes use of pleated paper as a filter medium, which is characterized both by greater initial efficiency than glassqfìber fabric and by increasing filtering efficiency throughout its life. This can be accomplished, for example, by molding the hollow body of pleated paper integrally with an elongated flexible polyurethane frame and with a pair of flexible polyurethane end closures to give a unit which is quite flexible, particularly as regards bending about axes parallel to the pleats which are themselves parallel to the longer dimension of the frame.

A second aspect of the invention comprises an air cleaner comprising a housing having an air outlet, a rectangular air inlet and a filter according to the first aspect of the invention disposed in the air inlet so that air passed through the filter flows to said air outlet.

There is now described, by way of example and with reference to the accompanying drawings, a filter and an air cleaner system containing it which are preferred embodiments of the first and second aspects respectively of the invention.

In the drawings, FIGURE 1 is an exploded partial view in perspective of a prior art air cleaning system; FIGURE 2 is a perspective view of the filter of the preferred embodiment parts being broken away for clarity of illustration; FIGURE 3 is a sectional view taken along the plane 3-3 of FIGURE 2; FIGURE 4 is a sectional view taken along the plane 4-4 of FIGURE 2; FIGURE 5 is a fragmentary detailed sectional view along the line 5--5 of FIGURE 4; FIGURE 6 is an enlarged fragmentary detailed sectional view of a portion of the filter; and FIGURE 7 schematically shows how the filter may be used in cramped quarters.

An understanding of our invention will be expedited by a brief consideration of the prior art system for which it is designed as an im provement. Here an air cleaner 10 is shown to have an airtight housing 11 with an air outlet opening 12 adapted to be connected by a conduit 13 to the air inlet of a diesel loco motive engine not shown. A front wall or panel 14 of the housing has a plurality of rectangular openings 15, (one of which is shown) the longer dimensions being vertical.

A filter "cartridge" or bag 16 is to be in serted bottom-first into each of these open ings, being received in a supporting cage 17 of wire carried by the housing. Each bag has an outturned flap to rest against the outside of panel 14 surrounding the opening, against which it is clamped by a frame 20 secured by fasteners 21. Carried by and projecting inwardly from frame 20 is an internal cage or supporting skeleton 22 which enters the bag as the frame is positioned, and thereafter prevents collapse or eversion of the bag, as a result of turbo-surge, for example.

FIGURE 2 is a perspective view of our improved filter, shown in more detail in FIGURES 3-6. The filter 26 is made up of a flexible U-shaped body 30, a resilient rectangular generally flat hollow mounting frame 311, and a pair of resilient end closures 32 and 33. Frame 31 has a pair of opposite short sides 34 and 35 and a pair of opposite long sides 36 and 37, dimensioned to be received in any of the openings 15, and also has at an outer surface a surrounding lip 40 perforated as at 41 to pass mounting fasteners, configured at 42 to seal against opening 15.

Body 30 extends from the inner surface of 369 in a direction normal thereto curves through 1800 at 43, and returns parallel to itself to the inner surface of side 37. It is formed of a filter medium of pleated paper 44, the pleats running parallel to sides 36 and 37, and is reinforced along its inner surface by beads 45 of plastic adhesive, and along its outer surface by similar beads 46. The beads are located generally along the inter sections, with the folds of the pleats, of planes perpendicular to frame 31. An additional.

stabilizing sheet 47 of reticulated material for example recticulated plastics material is secured to the outer folds of pleated paper 44 by beads 46.

The ends of filter 26 comprise closure means 32. and 33 of resilient, impervious material: in one embodiment of the invention frame 31 and closure means 32 and 33 were of resilient highly flexible polyurethane molded together. The ends of body 30 were in this unit molded into sides 37 and 36 of frame 31, and the free edges of sheet 47 and pleated paper 44 were molded into closure means 32, 33 to give an integral unit which was light, flexible, and shape-retaining. The unit is to be secured in housing 11 by a simple metal frame 52 and fasteners 53, and no internal cage or skeleton is required because each pleat of the paper acts as a beam strengthening the structure against collapse; the inner rim of frame 31 can be configured with a taper to facilitate entry into the filter of air to be cleaned.

FIGURE 7 shows how our new filter is advantageous, and should be compared with FIGURE 1. Note that in FIGURE 1 space must be available in front of panel 14 at least equal in width to the depth of skeleton 22, to permit removal of the latter prior to the removal of cartridge 16. FIGURE 7 shows that our filter is sufficiently flexible that it can be bent at substantially 900 for insertion into the housing, resuming its original shape thereafter, so that the working space W needed in front of the panel is proportionately lessened.

The filter of the preferred embodiment is light, flexible, and initially efficient, and its efficiency increases with use of the filter.

WHAT WE CLAIM IS:- 1. A filter comprising: a body of pleated paper, said body having a U-shaped cross-section in a plane transverse to. the fold lines of the pleats; two closure members secured respectively to the two edges of said body at the ends of the pleats to form with said body a hollow pocket; and an elongated rectangular frame secured to said body and defining the mouth of the pocket; wherein each of said closure members is resilient in its own plane whereby the filter can be bent about axes parallel to the pleats.

2. A filter according to Claim 1, in which the frame and said closure members have been formed as an integral moulding by moulding plastics material.

3. A filter according to Claim 2, in which during said moulding the two edges of said body at the ends of the pleats have been secured respectively to the plastics material forming said two closure members, and the edges of said body parallel to the pleats have been secured respectively to the plastics material forming the longitudinal sides of the rectangular frame.

4. A filter comprising a resilient, hollow, generally flat, rectangular frame having opposite surfaces and first and second pairs of spaced opposite parallel sides; a flexible body of pleated paper, having a U-shaped cross section transverse to the fold lines of the pleats, so as to define concave and convex faces, said body extending from a first end at a first side of one surface of said frame in a direction perpendicular to

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

detailed sectional view of a portion of the filter; and FIGURE 7 schematically shows how the filter may be used in cramped quarters.

An understanding of our invention will be expedited by a brief consideration of the prior art system for which it is designed as an im provement. Here an air cleaner 10 is shown to have an airtight housing 11 with an air outlet opening 12 adapted to be connected by a conduit 13 to the air inlet of a diesel loco motive engine not shown. A front wall or panel 14 of the housing has a plurality of rectangular openings 15, (one of which is shown) the longer dimensions being vertical.

A filter "cartridge" or bag 16 is to be in serted bottom-first into each of these open ings, being received in a supporting cage 17 of wire carried by the housing. Each bag has an outturned flap to rest against the outside of panel 14 surrounding the opening, against which it is clamped by a frame 20 secured by fasteners 21. Carried by and projecting inwardly from frame 20 is an internal cage or supporting skeleton 22 which enters the bag as the frame is positioned, and thereafter prevents collapse or eversion of the bag, as a result of turbo-surge, for example.

FIGURE 2 is a perspective view of our improved filter, shown in more detail in FIGURES 3-6. The filter 26 is made up of a flexible U-shaped body 30, a resilient rectangular generally flat hollow mounting frame 311, and a pair of resilient end closures

32 and 33. Frame 31 has a pair of opposite short sides 34 and 35 and a pair of opposite long sides 36 and 37, dimensioned to be received in any of the openings 15, and also has at an outer surface a surrounding lip 40 perforated as at 41 to pass mounting fasteners, configured at 42 to seal against opening 15.

Body 30 extends from the inner surface of 369 in a direction normal thereto curves through 1800 at 43, and returns parallel to itself to the inner surface of side 37. It is formed of a filter medium of pleated paper 44, the pleats running parallel to sides 36 and 37, and is reinforced along its inner surface by beads 45 of plastic adhesive, and along its outer surface by similar beads 46. The beads are located generally along the inter sections, with the folds of the pleats, of planes perpendicular to frame 31. An additional.

stabilizing sheet 47 of reticulated material for example recticulated plastics material is secured to the outer folds of pleated paper

44 by beads 46.

The ends of filter 26 comprise closure means 32. and 33 of resilient, impervious material: in one embodiment of the invention frame 31 and closure means 32 and 33 were of resilient highly flexible polyurethane molded together. The ends of body 30 were in this unit molded into sides 37 and 36 of frame 31, and the free edges of sheet 47 and pleated paper 44 were molded into closure means 32, 33 to give an integral unit which was light, flexible, and shape-retaining. The unit is to be secured in housing 11 by a simple metal frame 52 and fasteners 53, and no internal cage or skeleton is required because each pleat of the paper acts as a beam strengthening the structure against collapse; the inner rim of frame 31 can be configured with a taper to facilitate entry into the filter of air to be cleaned.

FIGURE 7 shows how our new filter is advantageous, and should be compared with FIGURE 1. Note that in FIGURE 1 space must be available in front of panel 14 at least equal in width to the depth of skeleton 22, to permit removal of the latter prior to the removal of cartridge 16. FIGURE 7 shows that our filter is sufficiently flexible that it can be bent at substantially 900 for insertion into the housing, resuming its original shape thereafter, so that the working space W needed in front of the panel is proportionately lessened.

The filter of the preferred embodiment is light, flexible, and initially efficient, and its efficiency increases with use of the filter.

WHAT WE CLAIM IS:- 1. A filter comprising: a body of pleated paper, said body having a U-shaped cross-section in a plane transverse to. the fold lines of the pleats; two closure members secured respectively to the two edges of said body at the ends of the pleats to form with said body a hollow pocket; and an elongated rectangular frame secured to said body and defining the mouth of the pocket; wherein each of said closure members is resilient in its own plane whereby the filter can be bent about axes parallel to the pleats.
2. A filter according to Claim 1, in which the frame and said closure members have been formed as an integral moulding by moulding plastics material.
3. A filter according to Claim 2, in which during said moulding the two edges of said body at the ends of the pleats have been secured respectively to the plastics material forming said two closure members, and the edges of said body parallel to the pleats have been secured respectively to the plastics material forming the longitudinal sides of the rectangular frame.
4. A filter comprising a resilient, hollow, generally flat, rectangular frame having opposite surfaces and first and second pairs of spaced opposite parallel sides; a flexible body of pleated paper, having a U-shaped cross section transverse to the fold lines of the pleats, so as to define concave and convex faces, said body extending from a first end at a first side of one surface of said frame in a direction perpendicular to

said surface, then curving through 1800, and then returning parallel to itself to a second end at a second side of said frame opposite said first side, the pleats of said body extending generally parallel to said first and second sides of said frame; means securing the first and second ends of said body in said first and second sides of said frame; and flat closure members, resilient in their own planes, secured to the other sides of said frame and to the edges of said body at the ends of the pleats.
5. A filter according to claim 4, in which said closure members and said ends of said body are moulded into said sides of said frame, and the ends of said pleats are moulded into said closure members, to result in an integral resilient filter.
6. A filter according to claim 4 or 5, having means extending along said convex face of said body, from said first side of said frame to said second side thereof, for reinforcing said body and stabilizing said pleats.
7. A filter according to Claim 4 or 5, having means extending along said convex and concave faces of said body from said first side of said frame to said second side thereof, for reinforcing said body and stabilizing said pleats.
18. A filter according to Claim 4 or 5, having means extending along at least one face of said body, from said first end to said second end thereof, for reinforcing said body and stabilizing said pleats.
9. A filter according to Claim 6, in which said means extending along said convex face comprises a sheet of reticulated material secured to said body along all the edges of said sheet and along mutually spaced lines extending on the convex face of said body from said first side of said frame to said second side thereof, and generally aligned with said closure members.
10. A filter according to Claim 6, adapted for insertion into a rectangular inlet opening of a filter housing, in which the rectangular frame is adapted to enter said inlet opening and has a lip to engage the wall of said housing around said opening; said means extending along said convex face includes at least one sheet of reticulated flexible material secured to said body along mutually spaced lines extending from said first side of said frame to said second side thereof and generally perpendicular to said pleats; said means securing the first and second ends of said body also secure said sheet in said first and second sides of said frame; and said flat closure members are in moulded relation to the other sides of said frame and to the edges of said sheet and of the body at the ends of the pleats.
11. A filter according to any of the preceding claims, substantially as described herein with reference to the accompanying drawings.
12. A filter substantially as described herein and substantially as shown in Figures 2 to 6 of the accompanying drawings.
13. An air cleaner comprising a housing having an air outlet, a rectangular air inlet and a filter according to any of the preceding claims, disposed in the air inlet so that air passed through the filter flows to said air outlet.
14. An air cleaner according to Claim 13, in which said filter comprises a resilient frame adapted for securement in said inlet, a flexible body of pleated paper extending from a first side of one surface of said frame to a second opposite side thereof and moulded into said sides, with said pleats extending generally parallel to said first and second sides of said frame, and flat closure members resilient in their own planes and in moulded relation to said surface of said frame at the other sides thereof and to the edges of the body at the ends of said pleats.
15. An air cleaner according to Claim 13 or 14, substantially as described herein with reference to the accompanying drawings.