WO2015002890A1

WO2015002890A1 - Assembly method for bag filter with two layers minimum

Info

Publication number: WO2015002890A1
Application number: PCT/US2014/044914
Authority: WO
Inventors: Stephen David HINER; Etienne René JARRIER
Original assignee: BHA Altair LLC
Current assignee: BHA Altair LLC
Priority date: 2013-07-01
Filing date: 2014-06-30
Publication date: 2015-01-08
Anticipated expiration: 2016-01-01

Abstract

A filter assembly includes a filter pocket having one or more sidewalls that filter a fluid. The sidewalls include one or more first layers for filtering first particulates including a liquid. The sidewalls include one or more second layers for filtering second particulates, the second particulates being finer than the first particulates.

Description

ASSEMBLY METHOD FOR BAG FILTER WITH TWO LAYERS MINIMUM

FIELD OF THE INVENTION

[0001] The invention relates generally to a filter media and, more particularly, to a filter media having an improved filtration efficiency.

BACKGROUND OF THE INVENTION

[0002] Filter assemblies may be used to provide clean fluid, such as air, to or from various devices. Such devices may include gas turbines. Filter elements may include a filter bag structure. As fluid passes through the filter bags, dust and other particles are captured on the surfaces of the media of the filter bags. The airflow rate through filter bags can be higher than desired. The filter bags can also have a higher differential pressure loss than desired. Higher airflow rates and higher differential pressure loss for the filter can result in entrapment of less dust or particulates resulting in shorter filter lives as well as reduced filtration efficiency. Further problems occur when the filter assemblies are filtering fluid that is in a marine or other environment that causes large amounts of liquids to be carried in the fluid to be filtered. There are benefits for continual improvements in filter technologies so as to address these and other issues.

SUMMARY OF THE INVENTION

[0003] In one embodiment, a new and improved filter assembly is provided. The new and improved filter assembly includes a filter pocketing having one or more sidewalls formed from one or more first layers configured to filter first particulates and one or more second configured to filter second particulates.

[0004] In one embodiment, the sidewalls include one or more third layers configured to support the first layer and the second layer.

[0005] In one embodiment, the first layer is positioned on one side of the second layer and the third layer is positioned on an opposing side of the second layer. [0006] In one embodiment, the first layer is rated to a filtration efficiency of about Gl to about G4 to EN779-2012.

[0007] In one embodiment, the second layer is rated to a filtration efficiency of about M5 to about F9 to EN779-2012.

[0008] In one embodiment, the second layer is arranged in a wave configuration. In one more particular embodiment, the first layer is upstream from the second layer such that the fluid passes through the first layer first.

[0009] In one embodiment, the second layer is an outer layer positioned outward from the first layer, and typically, downstream from the first layer.

[0010] In one embodiment, the first layer is upstream from the second layer. The first layer is configured to remove first particulates that are larger than the second particulates filtered by the second layer. The third layer is an open layer.

[0011] In another embodiment, the first particulates include a liquid.

[0012] In one embodiment, the wave configuration of the second layer provides a greater surface area for the second layer than the surface area of the first layer.

[0013] In one embodiment, the third layer is upstream of the second layer.

[0014] In one embodiment, the second layer includes a coarse support layer that is arranged into the wave configuration.

[0015] In another embodiment, a method of filtering a fluid with a filter assembly is provided. The method includes providing a filter pocket having one or more sidewalls, the sidewalls including one or more first layers and one or more second layers; filtering first particulates with the first layers, the first particulates including a liquid; and filtering second particulates with the second layers, the second particulates being finer than the first particulates. [0016] In one method, the first layer is positioned upstream of the second layer such that filter first particulates with the first layer occurs prior to filtering second particulates with the second layer.

[0017] In one method, the second layer is arranged in a wave configuration such that the second layer has a greater surface area than the first layer.

[0018] In one method, the second particulates include particulates selected from the group consisting of sand and salt.

[0019] In one method, the method includes supporting the first and second layers with a third layer.

[0020] In one method, the third layer is downstream from the first and second layers.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The foregoing and other aspects of the present invention will become apparent to those skilled in the art to which the present invention relates upon reading the following description with reference to the accompanying drawings, in which:

[0022] FIG. 1 is a schematized cross-section view of an example filter assembly including an example filter pocket in accordance with an aspect of the prevent invention;

[0023] FIG. 2 is a sectional view of a sidewall of the filter pocket in accordance with an aspect of the present invention;

[0024] FIG. 3 is a sectional view of the sidewall in which a fluid flows through the sidewall;

[0025] FIG. 4 is a graphical illustration of a prior filter assembly without a first layer; and

[0026] FIG. 5 is a graphical illustration of the example filter assembly including a first layer and a second layer.

DETAILED DESCRIPTION OF THE INVENTION [0027] Example embodiments that incorporate one or more aspects of the present invention are described and illustrated in the drawings. These illustrated examples are not intended to be a limitation on the present invention. For example, one or more aspects of the present invention can be utilized in other embodiments and even other types of devices. Moreover, certain terminology is used herein for convenience only and is not to be taken as a limitation on the present invention. Still further, in the drawings, the same reference numerals are employed for designating the same elements.

[0028] FIG. 1 illustrates an example filter assembly 10, according to some embodiments. In an example, the filter assembly 10 can be used for filtering air in a variety of environments. For example, the filter assembly 10 can be used to filter air in an offshore environment. In some examples, the offshore environments include maritime environments that are subject to rain, water, fog, sand, dust, etc. The filter assembly 10 is not limited to these environments. In some examples, the filter assembly 10 may be used in an inlet system for filtering air to a device, such as a gas turbine, filtration system, etc.

[0029] The filter assembly 10 includes at least one filter pocket 12. The at least one filter pocket 20 of the filter assembly 10 includes an open end 14 and a closed end 16. Fluid 18 (e.g., air flow, etc.) flows through the filter assembly 10 generally along a flow direction 20 and is filtered. In some examples, the fluid 18 is received at the open end 14 and proceeds along the flow direction 20 toward the closed end 16. It is to be appreciated that the specific fluid 18 being filtered is not a limitation upon the present invention. The fluid 18 can be liquid, air, or gas supplied to a filtration system, for example.

[0030] The filter assembly 10 can include any number of filter pockets 12. For example, the filter assembly 10 of FIG. 1 is illustrated as including four filter pockets 12. In other examples, however, the filter assembly 10 is not limited to four filter pockets, and, instead, may include one or more filter pockets 12. It will be appreciated that in this example, the four filter pockets 12 can be generally identical in structure, size, shape, etc. As such, most of the description herein is focused upon one of the filter pockets 12, with an understanding that similar structures and functions are present for the other three filter pockets 12. In some examples, it is contemplated that the four filter pockets 12 may have some differences. As such, it is to be understood that examples with differing filter pockets are still within the scope of the present invention, and that the present example is not an indication of the complete scope of the filter assembly 10.

[0031] The example filter assembly 10 of FIG. 1 can be used in a filter house with a plurality of filters for filtering particles (e.g., dust) and other particulate materials from a gaseous, fluid exhaust such as a combustion system of a gas turbine. The filter house can support a plurality of filter pocket assemblies. The example filter assembly 10 can also be used as a pre-filter or as a final filter. The type of dust/particulate matter/etc. that is filtered may be varied and is not a limitation upon the present invention.

[0032] The filter assembly 10 can include a frame 22. The frame 22 can have a variety of shapes and configurations. The frame 22 can be formed from any number of members and can form any shape, including, but not limited to, the quadrilateral shape shown in FIG. 1. The frame 22 can be configured to receive any number of filter pockets, including a single filter pocket. Each open end 14 of the filter pocket 12 is configured or shaped to fit the area bounded by the members of the frame 22. The members of the frame 22 receive an outer portion of the filter pocket(s) 12. It is to be appreciated that the members of the frame 22 can be

constructed/configured to hold, retain, affix, etc. the outer portions of the filter pockets 12.

[0033] The filter pockets 12 can include a plurality of sidewalls 24 formed of a filter material. The filter material can include any number of materials and can be formed by a variety of processes. Of course, one or more aspects of the filter material, such as material, construction, configuration, thickness, etc. can be varied. Such specifics are not limitations upon the scope of the present invention. The fluid 18 is filtered by the filter material as it passes through the at least one sidewall 24.

[0034] Turning now to FIG. 2, an example of one of the sidewalls 24 of a filter pocket 12 is illustrated. It will be appreciated that the sidewall 24 of FIG. 2 is illustrated in a partially exploded/detached state for illustrative purposes (e.g., layers 40, 50, and 60 are separated from each other). In operation, however, the various layers 40, 50, and 60 forming the sidewall 24 can be attached to each other, such as, but not limited to, fasteners (e.g., sewing, adhesives, mechanical fasteners, etc.). [0035] The sidewall 24 can separate an inlet side 30 and an outlet side 32. In an example, the fluid 18 can flow along the flow direction 20 from the inlet side 30 to the outlet side 32. In an example, the sidewall 24 includes one or more first layers 40. The first layer 40 can be positioned to separate the inlet side 30 from an opposing second side 42. The first layer 40 includes any number of materials that can filter the fluid 18. In some examples, the first layer 40 includes a filter media. The first layer 40 can include, for example,

Polytetrafluoroethylene (PTFE), poly propylene airlaid non woven material, etc. The first layer 40 is rated to a filtration efficiency of about Gl to about G4 to EN779-2012. The first layer 40 can filter and drain, for example, liquid (e.g., water droplets, etc.), relatively larger particulates, etc., while smaller/finer particulates can pass through the first layer 40. The first layer 40 includes any number of thicknesses. In some examples, the first layer 40 includes a thickness of about 4 millimeters (mm) to about 30 mm.

[0036] The sidewall 24 can include one or more second layers 50. In an example, the fluid 18 can flow along the flow direction 20 from the second side 42 to an opposing third side 52. The fluid 18 can flow through the second layer 50 from the second side 42 to the third side 52, which causes the fluid 18 to be filtered. The second layer 50 includes any number of materials that can filter the fluid 18. In some examples, the second layer 50 is held in a waved or curvilinear configuration (illustrated generically/schematically with wave pattern). By including the waved/curvilinear configuration, the second layer 50 has an increased surface area which can result in improved filtration efficiency or reduced pressure loss. In some examples, the second layer 50 can include one or more coarse support layers, one or more fine fiber filtration layers, one or more membrane layers, etc. In an example, the one or more coarse support layers, fine fiber filtration layers, membrane layers, etc. are arranged/constructed into the wave pattern, such that filtration efficiency is improved.

[0037] The second layer 50 can include any number of materials. According to some examples, the second layer 50 includes polyolefms, such as polypropylene and polyethylene; polyesters, such as polybutylene terephthalate and polyethylene terephthalate; polyamides, such as Nylon; polycarbonate; polyphenylene sulfide; polystyrene; polyurethane; glass fibers, etc. In some examples, the second layer 50 can include, alone or in combination,

polytetrafluoroethylene (PTFE) (e.g., expanded or unexpanded), polyethylene (e.g., linear low density, ultra high molecular weight), polypropylene, polycarbonate, polyester, nitrocellulose- mixed esters, polyethersulfone, cellulose acetate, polyimide, cellulose acetate, polyvinylidene fluoride, polyacrylonitrile, polysulfone, polyethersulfone, and polyamide, amongst others.

[0038] In some examples, the second layer 50 is rated to a filtration efficiency of about M5 to about F9 to EN779-2012. The second layer 50 can filter, for example, relatively finer particulates. In an example, the first layer 40 will filter the larger particulates, including liquids (e.g., water droplets, etc.), while the smaller/finer particulates that pass through the first layer 40 are filtered by the second layer 50. The second layer 50 can include any number of thicknesses. In some examples, the second layer 50 includes a thickness of about 3 mm to about 20 mm.

[0039] The sidewall 24 can include one or more third layers 60. In an example, the fluid 18 can flow along the flow direction 20 from the third side 52 to the outlet side 32 on an opposing side of the third layer 60. The third layer 60 can include a support material, such that the third layer 60 can function as a support layer. In some examples, the third layer 60 can support the first layer 40 and second layer 50. The filter assembly 10 is not limited to including the third layer 60, as the third layer 60 is optional and may not be provided in some examples. The third layer 60 includes any number of support materials, including metals, polyesters, etc., and can be constructed as a mesh, scrim, or the like. In some examples, a thickness of the third layer 60 can vary from about 0.1 mm to about 5 mm. In general, the third layer 60 can be generally open, so as to reduce pressure loss of the fluid 18 flowing through the third layer 60. The third layer 60 is not limited to the illustrated position (e.g., adjacent the second layer 50 on an opposite side of the first layer 40). Rather, in other examples, the third layer 60 can be positioned at the inlet side 30, between the first layer 40 and second layer 50, or the like.

[0040] Turning now to FIG. 3, an example operation of the sidewall 24 of the filter assembly 10 is illustrated. In this example, the first layer 40 can filter out first particulates 100 (illustrated generically/schematically with arrowheads). In an example, the first particulates 100 include relatively larger particulates, including liquids or water droplets, for example. The first particulates 100 are generally limited and/or prevented from passing through the first layer 40 from the inlet side 30 to the second side 42. Rather, the first particulates 100 can remain on a surface (and/or coalesced through a depth of the media) of the first layer 40. In some examples, when the first particulates 100 include liquid or water droplets, the liquid can accumulate on the surface (and/or coalesced through a depth of the media) of the first layer 40. The liquid coalesces so as to increase in size/weight on the surface (and/or through a depth of the media) of the first layer 40. Once the liquid has coalesced to a certain size/weight, the liquid (e.g., first particulates 100) will fall from the first layer 40, as illustrated. Accordingly, the first particulates 100 are generally limited from accumulating on the surface (and/or through a depth of the media) of the first layer 40, thus limiting pressure loss of fluid 18 flowing through the first layer 40.

[0041] The second layer 50 can filter out second particulates 102 (illustrated

generically/schematically with arrowheads). In an example, the second particulates 102 include relatively finer particulates that have passed through the first layer 40. For example, the second particulates 102 can include airborne particulates such as salt, sand, dust, etc. Due to the second layer 50 comprising the wave media (e.g., waved/curvilinear configuration), the second layer 50 has an increased surface area to improve filtration efficiency or reduce pressure loss. The second layer 50 can limit and/or prevent the second particulates 102 from passing through the second layer 50 from the second side 42 to the third side 52. Rather, the second particulates 102 can remain on a surface of the second layer 50. In some examples, the second particulates 102 can fall from the second layer 50, as illustrated. Accordingly, the second particulates 102 can be generally limited from accumulating on the surface of the second layer 50, thus limiting pressure loss of fluid 18 flowing through the second layer 50.

[0042] Filtered air flow 104 can pass through the second layer 50 from the second side 42 to the third side 52. In an example, the air flow 104 is filtered as it passes through the first layer 40. In particular, the first particulates 100 are filtered from the air flow 104 as the air flow 104 passes through the first layer 40. Similarly, the second particulates 102 are filtered from the air flow 104 as the air flow 104 passes through the second layer 50. As such, the air flow 104 exiting the second layer 50 comprises filtered air flow 104. This filtered air flow 104 can pass through the third layer 60 and exit the sidewall 24.

[0043] The filter assembly 10 includes a number of benefits. For example, the first layer 40 and second layer 50 can selectively filter different particulates (e.g., the first particulates 100 and second particulates 102). In an example, the first layer 40 can filter out the first particulates 100, including liquids, water droplets, dust, etc. These first particulates 100 can coalesce and/or merge, thus allowing the first particulates 100 to be drained from or fall from the first layer 40. Since the first particulates 100 tend to not accumulate on the first layer 40, pressure loss/drop of fluid 18 passing through the first layer 40 is reduced. The second particulates 102, which are relatively finer/smaller than the first particulates 100, can then be filtered by the second layer 50.

[0044] Turning now to FIG. 4, a graphical illustration of a prior filter assembly is illustrated. In this example, the prior filter assembly included the second layer, but not the first layer. The graphical illustration of FIG. 4 plots pressure loss (in Pascal) along the y-axis against time (in hours) along the x-axis. In this prior example, it can be seen that the prior filter assembly exhibits a relatively large fluctuation in pressure loss when challenged with water droplets for air flowing through filter assembly over a period of time. In particular, pressure loss for this prior filter assembly exceeds 1000 Pascal in some situations.

[0045] Turning now to FIG. 5, a graphical illustration of the example filter assembly 10 described with respect to FIGS. 1 to 3 is shown. In this example, the filter assembly 10 includes the first layer 40, second layer 50, and third layer 60. The graphical illustration of FIG. 5 plots pressure loss (in Pascal) along the y-axis against time (in hours) along the x-axis. In this example, it can be seen that the filter assembly 10 exhibits a negligible fluctuation in pressure loss when challenged with water droplets for air flowing through the filter assembly 10 over time. In particular, the pressure loss of the air remained below 400 Pascal during the entire two hour testing period. As explained above, by providing the first layer 40, pressure loss through the filter assembly 10 is reduced due, at least in part, to the first particulates 100 coalescing and falling from the filter assembly (e.g., not accumulating on the outer surface).

[0046] The invention has been described with reference to the example embodiments described above. Modifications and alterations will occur to others upon a reading and understanding of this specification. Example embodiments incorporating one or more aspects of the invention are intended to include all such modifications and alterations insofar as they come within the scope of the appended claims. [0047] All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0048] The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non- claimed element as essential to the practice of the invention.

[0049] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

CLAIMS What is claimed is:

1. A filter assembly including:

a filter pocket having one or more sidewalls that are configured to filter a fluid, the sidewalls including:

one or more first layers configured to filter first particulates; and

one or more second layers configured to filter second particulates.

2. The filter assembly of claim 1, wherein the sidewalls include one or more third layers configured to support the first layer and the second layer.

3. The filter assembly of claim 2, wherein the first layer is positioned on one side of the second layer and the third layer is positioned on an opposing side of the second layer.

4. The filter assembly of claim 1, wherein the first layer is rated to a filtration efficiency of about Gl to about G4 to EN779-2012.

5. The filter assembly of claim 1, wherein the second layer is rated to a filtration efficiency of about M5 to about F9 to EN779-2012.

6. The filter assembly of claim 1 , wherein the second layer is arranged in a wave configuration,

7. The filter assembly of claim 6, wherein the first layer is upstream from the second layer such that the fluid passes through the first layer first.

8. The filter assembly of claim 7, wherein the second layer is an outer layer positioned outward from the first layer.

9, The filter assembly of claim 2, wherein: the first layer is upstream from the second layer;

the first layers is configured to remove first particulates that are larger than the second particulates filtered by the second layer; and

the third layer is an open layer.

10. The filter assembly of claim 4, wherein the second layer is rated to a iiltration efficiency of about M5 to about F9 to EN779-2012.

11. The filter assembly of claim 2 , wherein:

the first layer is upstream from the second layer;

wherein the first particulates include a liquid.

12. The fi lter assembly of claim 6, wherem the second layer has a greater surface area than the first layer.

13. The filter assembly of claim 2, wherein the third layer is upstream of the second layer.

14. The fi lter assembly of claim 6, wherein the second layer includes a coarse support layer that is arranged into the wave configuration.

15. A method of filter a fluid with a filter assembly, the method including:

providing a filter pocket having one or more sidewalls, the sidewalls including one or more first layers and one or more second layers;

filtering first particulates with the first layers, the first particulates including a liquid; and filtering second particulates with the second layers, the second particulates being finer than the first particulates.

16. The method of claim 15, wherein the first layer is positioned upstream of the second layer such that filter first particulates with the first layer occurs prior to filtering second particulates with the second layer.

17. The method of claim 16, wherein the second layer is arranged in a wave configuration such that the second layer has a greater surface area than the first layer.

18. The method of claim 15, wherein the second particulates include particulates selected from the group consisting of sand and salt.

19. The method of claim 15, further comprising supporting the first and second layers with a third layer.

20. The method of claim 19, wherein the third layer is downstream from the first and second layers.