WO2015160608A1

WO2015160608A1 - High temperature filter cartridge

Info

Publication number: WO2015160608A1
Application number: PCT/US2015/025041
Authority: WO
Inventors: Kyle NANNENGA; Mark Belcher
Original assignee: Donaldson Company, Inc.
Priority date: 2014-04-14
Filing date: 2015-04-09
Publication date: 2015-10-22

Abstract

A filter cartridge includes a length of filtration media that is circumferentially pleated. The length of filtration media extends between a first open end and an opposing closed end. An end cap formed of a silicon elastomer defines a gas outlet and is molded to the first open end.

Description

HIGH TEMPERATURE FILTER CARTRIDGE

FIELD

[0001] The disclosure relates to filter elements and, in particular to pleated filter elements that filter particulate material from high temperature gas streams.

BACKGROUND

[0002] Gas streams often carry particulate material therein. In many instances, removal of some or all of the particulate material from a gas flow stream is needed. For example, production gases or off gases may contain particulate material, for example, those generated by processes that included mining, milling, chemical processing, sintering, painting, energy production, etc. Before such gases can be, or should be, directed through various downstream equipment and/or to the atmosphere, a substantial removal of particulate material from those streams is important.

[0003] Baghouses, also known as dust collectors, for filtering particulate-laden air are well known. Conventional baghouses have a large housing with an upper, clean air chamber and a lower, dirty air chamber. The two chambers, commonly referred to as plenums, are separated by a sheet of metal, commonly referred to as a tube sheet or cell plate. The tube sheet has a number of openings therein from which cylindrical filters, such as bags or cartridges, are aligned. The filters suspend downwardly from the tube sheet openings into the dirty air chamber. Particulate-laden air is introduced into the dirty air chamber, and the particulates collect onto the filters. The filtered air passes through the filters to the interior of the filters, and upwardly out through the openings in the tube sheet into the clean air chamber. From the clean air chamber, the cleaned air is exhausted into the environment, or recirculated for other uses. [0004] An objective in the design of a baghouse, and more particularly in the design of a filter bag or cartridge and its support structure, is that a seal exist between each filter element and the tube sheet. Otherwise, in the absence of a seal, particulate-laden air will seep around the filter element, through the tube sheet aperture, and into the clean air chamber, thereby contaminating the clean air. Additionally, because the filter elements require periodic replacement, it is important that the filter elements are easily removable and replaceable.

BRIEF SUMMARY

[0005] The disclosure relates to filter elements and, in particular to pleated filter elements that filter particulate material from gas streams. The pleated filter elements can withstand high temperatures, such as up to 135 degrees centigrade or up to 150 degrees centigrade or greater.

[0006] In many embodiments, a filter cartridge includes a length of filtration media that is circumferentially pleated. The length of filtration media extends between a first open end and an opposing closed end. An end cap formed of a silicon elastomer defines a gas outlet and is molded to the first open end.

[0007] In further embodiments, a method of manufacturing a filter cartridge having a length of filtration media that is circumferentially pleated and defining a first open end fixed to a silicon elastomer end cap is described. This method of manufacturing includes providing a mold defining a cavity for forming the end cap. The end cap defines a gas outlet. Then placing the first open end of the circumferentially pleated filtration media in the mold and introducing silicon elastomer into the cavity of the mold. The method then includes forming the end cap onto the open end of the circumferentially pleated filtration media from the silicon elastomer within the cavity of the mold to form the filter cartridge and removing the end cap portion of the filter cartridge from the cavity of the mold. [0008] In still further embodiments, a filter cartridge includes a length of filtration media that is circumferentially pleated and has aramid fibers or aromatic polyamide fibers. The length of filtration media extends between a first open end and an opposing closed end. An end cap is formed of a silicon elastomer and defining a gas outlet and is molded to the first open end. The first open end extends into the silicon elastomer of the end cap.

[0009] The details of one or more embodiments of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the disclosure will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The disclosure may be more completely understood in consideration of the following detailed description of various embodiments of the disclosure in connection with the accompanying drawings, in which:

[0011] FIG. 1 is a schematic diagram of an illustrative dust collector;

[0012] FIG. 2 is a schematic diagram of an illustrative filter cartridge;

[0013] FIG. 3 is a schematic diagram view of the filter cartridge of FIG. 2 taken along lines 3-3;

and

[0014] FIG. 4 is a schematic diagram of an open end portion of the filter cartridge of FIG. 2.

[0015] The schematic drawings presented herein are not necessarily to scale. Like numbers used in the figures refer to like components, steps and the like. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number. In addition, the use of different numbers to refer to components is not intended to indicate that the different numbered components cannot be the same or similar. DETAILED DESCRIPTION

[0016] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration several specific embodiments of devices, systems and methods. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense.

[0017] All scientific and technical terms used herein have meanings commonly used in the art unless otherwise specified. The definitions provided herein are to facilitate understanding of certain terms used frequently herein and are not meant to limit the scope of the present disclosure.

[0018] As used in this specification and the appended claims, the singular forms "a", "an", and

"the" encompass embodiments having plural referents, unless the content clearly dictates otherwise.

[0019] As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise.

[0020] As used herein, "have", "having", "include", "including", "comprise", "comprising" or the like are used in their open ended sense, and generally mean "including, but not limited to." It will be understood that the terms "consisting of and "consisting essentially of are subsumed in the term "comprising," and the like.

[0021] Any direction referred to herein, such as "top," "bottom," "left," "right," "upper,"

"lower," "above," below," and other directions and orientations are described herein for clarity in reference to the figures and are not to be limiting of an actual device or system or use of the device or system. Many of the devices, articles or systems described herein may be used in a number of directions and orientations. [0022] The disclosure relates to filter elements and, in particular to pleated filter elements that filter particulate material from high temperature gas streams. The pleated filter elements can withstand high temperatures, such as up to 125 degrees centigrade or 135 degrees centigrade or up to 150 degrees centigrade or greater. An end cap formed of a silicon elastomer defines a gas outlet of the filter cartridge and is molded to the first open end. The silicon elastomer end cap can be molded integrally with an end surface of the pleated filtration media and provide mechanical support for the pleated filtration media and assist in providing isolation between chambers in the dust collector. While the present disclosure is not so limited, an appreciation of various aspects of the disclosure will be gained through a discussion of the examples provided below.

[0023] With reference initially to FIG. 1, a dust collector (also referred to as a baghouse, for example) is denoted generally by reference numeral 10. Dust collector 10 is formed generally of a housing 12 separated into upper and lower chambers 14, 16 respectively, by a tube sheet 18. The dust collector 10 has a collection hopper 19 at its bottom portion. A plurality of filter elements 20 are suspended from tube sheet 18 into the lower chamber 16, and are held in place by attachment structure, denoted generally by reference numeral 22 in FIG. 1. An inlet 24 communicates with lower chamber 16 and an outlet 26 communicates with upper chamber 14.

[0024] The structure and operation of baghouse 10 will be readily appreciated by those with skill in the art. Described briefly, particulate-laden air is introduced into lower chamber 16 through inlet 24. The particulates collect onto filter elements 20, and the cleaned air exits out through the interior of the filters, upwardly through apertures in the tube sheet, and into the clean air chamber 14 where it is exhausted through outlet 26.

[0025] In particular embodiments, the filter elements 20 have a length that does not extend into the direct air flow from the inlet 24. This is useful when the air flow from the inlet 24 includes abrasive particles that can erode or damage the filter elements 20. For example, conventional planar filter cartridges having a standard length can be replaced with pleated filter cartridges having a length that is from about 50% to about 33% the length of the standard length while maintaining the same filtering area. This is useful in reducing the amount of abrasion or erosion caused by abrasive particles that is in the air flow from the inlet 24. Pleated filter cartridges can have about 6 times or greater surface area as compared to non-pleated filter cartridges at the same length.

[0026] FIG. 2 is a schematic diagram of an illustrative filter cartridge 20. FIG. 3 is a schematic diagram of the filter cartridge 20 of FIG. 2 taken along lines 3-3. FIG. 4 is a schematic diagram of an open end portion 31 of the filter cartridge 20 of FIG. 2.

[0027] The filter cartridge 20 can have any useful cross-sectional shape. Preferably the filter cartridge 20 can have an oval cross-sectional shape as illustrated in FIG. 3. Oval shaped filter cartridges 20 have been found to provide better snap during cleaning as compared to filter cartridge having a round cross-sectional shape. This allows the particulates to be more easily removed or knocked off the filter cartridge 20 during pulse cleaning. In addition this allows for lower pressure drop and longer filter cartridge life.

[0028] The filter cartridge 20 includes a length of filtration media 30 that is circumferentially pleated. The length of filtration media 30 extends between a first open end 31 and an opposing closed end 32. An end cap 40 or end collar 40 is formed of a silicon elastomer and defines a gas outlet 42 and is molded to the first open end 31. Preferably the entire end cap or end collar 40 is formed of the silicon elastomer described herein. The closed end 32 can include a metal or rigid pan 38 sealed to the filtration media with a useful adhesive. In other embodiments the closed end 32 can include a molded polymer rigid pan 38 that can be molded to the filtration media 30 and assist in maintaining the pleated structure of the pleated filtration media 30. In some embodiments, the molded polymer rigid pan 38 is formed of a similar material as the end cap or collar 40 material, such as a silicon elastomer, as described below. The molded polymer rigid pan 38 can mechanically maintain the circumferentially pleated closed end 32. In some embodiments the rigid pan 38 includes a metal pan disposed on a molded polymer rigid pan. [0029] The silicon elastomer end cap or collar 40 material can directly bond to an exterior surface 36 of the filtration media 30. The silicon elastomer end cap or collar 40 material can directly bond to an exterior surface 36 of the filtration media 30 and can directly bond to an interior surface 35 of the filtration media. The silicon elastomer end cap or collar 40 material can extend into or through the filtration media 30. The silicon elastomer end cap or collar 40 material can mechanically maintain the circumferentially pleated first open end 31.

[0030] The silicon elastomer end cap or collar 40 material can be any useful silicon elastomer material. The silicon elastomer can withstand (is stable at) high temperatures, such as up to 135 degrees centigrade or up to 150 degrees centigrade or greater. In many embodiments the silicon elastomer is a polydimethylsiloxane elastomer. Useful polydimethylsiloxane elastomers are available under the trade designation SLYGARD silicone from Dow Corning (USA).

[0031] The silicon elastomer can be injection molded to form the end cap or collar 40 for the first open end 31 of the filter cartridge 20. The end cap or collar 40 defines the gas outlet 42. The end cap or collar 40 can completely encase the pleated first open end 31 and the exterior surface 36 and the interior surface 35 of the filtration media 30 can be embedded within the end cap or collar 40.

[0032] An illustrative method includes providing a mold defining a cavity for forming the end cap (the end cap defines a gas outlet of the filter cartridge) and placing the first open end of the circumferentially pleated filtration media in the mold. Then introducing silicon elastomer into the cavity of the mold and forming the end cap onto the open end of the circumferentially pleated filtration media from the silicon elastomer within the cavity of the mold to form the filter cartridge. Then the method includes removing the end cap portion of the filter cartridge from the cavity of the mold. The forming step flows the silicon elastomer into and through the filtration media. The forming step mechanically maintains the circumferentially pleated first open end, as described above. [0033] The filtration media 30 can be formed of any useful filtration material. The filtration media 30 can withstand (is stable at) high temperatures, such as up to 135 degrees centigrade or up to 150 degrees centigrade or greater. The filtration media 30 can include aramid fibers or aromatic polyamide fibers. In many embodiments the filtration media 30 can include meta-aramid fibers. The aramid fibers or aromatic polyamide fibers can extend into the silicon elastomer end cap. Useful aramid fibers or aromatic polyamide fibers are available under the trade designations NOMAX or KEVLAR from DuPont (USA).

[0034] Referring to FIG. 4, a rigid collar 50 can be attached to the silicon elastomer end cap 40

for fixing the filter cartridge 20 to the tube sheet 18 as illustrated in FIG. 1. The rigid collar 50 can be fixed to the silicon elastomer end cap 40 by injection molding the silicon elastomer end cap 40 onto the rigid collar 50. The rigid collar 50 can be any useful material such as metal. Fasteners 52 such as bolts can fix the rigid collar 50 and filter element 20 to the tube sheet 18 of the dust collector 10.

[0035] A gasket 54 can be disposed between the end cap 40 and the tube sheet 18 to aid in sealing the upper chamber 14 from the lower chamber 16. A gasket 54 can be placed about the silicon elastomer end cap 40 and assist in isolating the two chambers of the dust collector (shown in FIG. 1). The gasket 54 can be any useful material can withstand (is stable at) high temperatures, such as up to 135 degrees centigrade or up to 150 degrees centigrade or greater. The gasket material can be a different type of material than the material forming the end cap, such as silicone, for example.

[0036] The filter cartridge 20 can further include a screen or cage positioned within and supporting the pleated filtration media. The screen or cage can be fixed to the silicon elastomer end cap 40 via molding the silicon elastomer end cap 40 to the screen or cage. The screen or cage can be also fixed to the rigid pan 38 sealing the closed end 32 of the filter cartridge 20. Thus, embodiments of HIGH TEMPERATURE FILTER CARTRIDGE are disclosed. One skilled in the art will appreciate that the optical films and film articles described herein can be practiced with embodiments other than those disclosed. The disclosed embodiments are presented for purposes of illustration and not limitation.

Claims

What is claimed is:

1. A filter cartridge comprising: a length of filtration media that is circumferentially pleated, the length of filtration media extending between a first open end and an opposing closed end; an end cap formed of a silicon elastomer and defining a gas outlet and molded to the first open end.

2. The filter cartridge according to claim 1, wherein the silicon elastomer is a polydimethylsiloxane elastomer.

3. The filter cartridge according to any of the preceding claims, wherein the silicon elastomer directly bonds to an exterior surface of the filtration media.

4. The filter cartridge according to any of the preceding claims, wherein the silicon elastomer directly bonds to an exterior surface of the filtration media and directly bonds to an interior surface of the filtration media.

5. The filter cartridge according to any of the preceding claims, wherein the silicon elastomer extends into the filtration media.

6. The filter cartridge according to any of the preceding claims, wherein the silicon elastomer mechanically maintains the circumferentially pleated first open end.

7. The filter cartridge according to any of the preceding claims, wherein the filtration media comprises aramid fibers or aromatic poly amide fibers.

8. The filter cartridge according to any of the preceding claims, wherein the filtration media comprises meta-aramid fibers.

9. The filter cartridge according to any of the preceding claims, wherein the aramid fibers or aromatic polyamide fibers extends into the silicon elastomer end cap.

10. A method of manufacturing a filter cartridge having a length of filtration media that is circumferentially pleated and defining a first open end fixed to a silicon elastomer end cap, the method of manufacturing comprises: providing a mold defining a cavity for forming the end cap, wherein the end cap defines a gas outlet;

placing the first open end of the circumferentially pleated filtration media in the mold;

introducing silicon elastomer into the cavity of the mold;

forming the end cap onto the open end of the circumferentially pleated

filtration media from the silicon elastomer within the cavity of the mold to form the filter cartridge; and

removing the end cap portion of the filter cartridge from the cavity of the mold.

11. The method according to claim 10, wherein the silicon elastomer is a

polydimethylsiloxane elastomer.

12. The method according to claims 10 or 11, wherein the forming step directly bonds the silicon elastomer to an exterior surface of the filtration media and directly bonds the silicon elastomer to an interior surface of the filtration media.

13. The method according to claims 10 to 12, wherein the forming step flows the silicon elastomer into the filtration media.

14. The method according to claims 10 to 13, wherein forming step mechanically maintains the circumferentially pleated first open end.

15. The method according to claims 10 to 14, wherein the filtration media comprises aramid fibers or aromatic polyamide fibers.

16. The method according to claims 10 to 15, wherein the filtration media comprises meta-aramid fibers.

17. The method according to claims 10 to 16, wherein the forming step encloses the aramid fibers or aromatic polyamide fibers within the silicon elastomer end cap.

18. The method according to claims 11 to 17, wherein the forming step comprises injection molding the end cap onto the open end of the circumferentially pleated filtration media from the silicon elastomer within the cavity of the mold to form the filter cartridge.

19. A filter cartridge comprising: a length of filtration media that is circumferentially pleated and comprises aramid fibers or aromatic polyamide fibers, the length of filtration media extending between a first open end and an opposing closed end; an end cap formed of a silicon elastomer and defining a gas outlet and molded to the first open end, wherein the first open end extends into the silicon elastomer of the end cap.

20. The filter cartridge according to claim 19, wherein the silicon elastomer is a polydimethylsiloxane elastomer.