FILTER POCKET ARRANGEMENT WITH INCREASED FILTER MEDIA AREA
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to filtration, and more
particularly, to a filter assembly that utilizes a filter pocket arrangement that provides increased filter media area.
[0002] Filter assemblies are suitable for use in a multitude of applications.
For example, a filter assembly can be used as part of an intake system that provides large quantities of air to a gas turbine for combustion. To maintain suitable performance of the gas turbine, the filter assembly of the intake system filters the intake air to remove unwanted dust, moisture, and other contaminants that can damage components of the gas turbine. Typically, the filter assembly of the intake system utilizes an array of filters to primarily filter the intake air supplied to the gas turbine.
[0003] An array of filter pockets is one type of filter assembly that may be
used in a gas turbine air intake system. A filter pocket generally has a pair of flat panel filtration media connected together at an apex to form an opening that extends outwardly away from the apex. A typical array of filter pockets includes three or four filter pockets placed in a filter frame. Performance of this type of array of filter pockets is determined generally by the filter media and the size of each pocket (i.e., open area), which essentially corresponds to the surface area of the pocket. Generally, manufacturers try to improve the performance of the array of filter pockets by making the surface area of each pocket deeper, however, the depth that these
pockets can be extended are generally limited by the size of the filter housing that the filter pockets are placed in.
BRIEF DESCRIPTION OF THE INVENTION
[0004] In one aspect of the present invention, a filter assembly is provided. The filter assembly comprises a filter frame and a plurality of filter pockets disposed in the filter frame. Each of the plurality of filter pockets comprises a pocket mouth that attaches to the filter frame and a pocket body extending longitudinally away from the pocket mouth to a closed end. The closed end is folded back onto itself to form a tuck fold that defines a first sub-filter pocket and a second sub-filter pocket at the pocket mouth. The first sub-filter pocket and the second sub-filter pocket are each located about the pocket mouth and each has a sub-pocket mouth with sidewalls extending longitudinally therefrom to form an apex at the closed end of the filter pocket. The first sub-filter pocket is separated from the second sub-filter pocket by the tuck fold. The filter assembly further comprises a plurality of supporting members that support the plurality of filter pockets within the filter frame. Each of the plurality of supporting members is located about a tuck fold to support at least one of the plurality of filter pockets.
[0005] In another aspect of the present invention, a filter pocket arrangement is provided. In this aspect of the present invention, the filter pocket arrangement comprises a filter frame and a plurality of filter pockets disposed in the filter frame. Each of the plurality of filter pockets comprises a pocket mouth that attaches to the filter frame and a pocket body extending longitudinally away from the pocket mouth
to a closed end. The closed end is folded back inward towards the pocket mouth to form a tuck fold that defines a first sub-filter pocket and a second sub-filter pocket at the pocket mouth. The first sub-filter pocket and the second sub-filter pocket each has a sub-pocket mouth that coincides with a portion of the pocket mouth, with sidewalls extending longitudinally therefrom to form an apex at the closed end of the filter pocket. The first sub-filter pocket is separated from the second sub-filter pocket by the tuck fold. The filter pocket arrangement further comprises a plurality of supporting members that support the plurality of filter pockets within the filter frame. Each of the plurality of supporting members is located at the tuck fold of at least one of the plurality of filter pockets.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a schematic view of a filter assembly, constructed according to
one embodiment of the present invention, for use with an air intake system of a gas
turbine;
[0007] FIG. 2 is an enlarged perspective view of a portion of the air intake system
illustrated in FIG. 1 according to one embodiment of the present invention;
[0008] FIG. 3 is a perspective view of one embodiment of a filter assembly used in
the air intake system illustrated in FIGS. 1-2;
[0009] FIG. 4 is a perspective view showing a more detailed view of one filter
pocket from the filter assembly of FIG. 3 according to one embodiment of the present
invention;
[0010] FIG. 5 is a side view of the filter pocket depicted in FIG. 4 according to one embodiment of the present invention;
[0011] FIG. 6 is a front elevation view of an alternative embodiment of a filter assembly used in the air intake system illustrated in FIGS. 1-2; and
[0012] FIG. 7 is a top view of the filter assembly depicted in FIG. 6 according to one embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0013] Referring to the drawings, FIG. 1 illustrates a power generation unit 20. The power generation unit 20 includes a gas turbine 22 and an intake air filter system 24. Although the description that follows is directed to a filter assembly used with a gas turbine, various embodiments of the present invention are suitable for use with other turbines, such as for example, steam turbines. Referring back to FIG. 1, air from the surrounding environment is drawn into intake air filter system 24 for filtration and delivery to gas turbine 22. Power generation unit 20 may be used in any of numerous applications, such as, without limitation, generating electrical power by means of a generator 26 or providing motive power, directly or indirectly. [0014] Intake air filter system 24 includes an air intake housing 40. Air intake housing 40 may be made from any suitable material, such as sheet metal. A filter assembly holding frame 42 is disposed in air intake housing 40. Filter assembly holding frame 42 may be made from any suitable material, such as metal tubes, channels, beams or extrusions that are fixed to one another by suitable attachment means such as welding. Filter assembly holding frame 42 supports a plurality of
filters or filter assemblies 44, according to one embodiment of the present invention.
Filter assemblies 44 remove contaminants such as dust, dirt, moisture, salt, carbon and
other contaminants from the air that may tend to reduce the performance or service
life of gas turbine 22. In one embodiment, air intake housing 40 may be several
stories high, and may contain up to several hundred filter assemblies 44, which may
be held by several filter assembly holding frames 42.
[0015] As shown in FIG. 1, gas turbine 22 includes an air compressor section 60
that draws intake air into gas turbine 22 for combustion in a combustor section 62 and
work in a turbine section 64. The air is drawn first from the surrounding environment
through hoods 66 of the air intake housing 40. As the intake air enters air intake
housing 40 through hoods 66, it may first pass through a prefilter or a de-mister 68.
The air then flows through the array of filter assemblies 44 for primary or final
filtration before it is directed to compressor section 60.
[0016] As illustrated in FIG. 2, filter assembly holding frame 42 includes a set of
vertical supports 70 and horizontal supports 72 that support an array of filter
assemblies 44. Filter assemblies 44 may be held in place in filter assembly holding
frame 42 by any suitable means, such as clamps or latches (not shown). Filter
assemblies 44 may be any suitable filter type, such as for example, filter pockets. In
one embodiment, filter assemblies 44 may be constructed as high-efficiency
AltairSupernova™ filters, available from the General Electric Company.
Furthermore, filter assemblies 44 may be of any suitable size, construction,
configuration or material.
[0017] FIGS. 3-5 provide detailed views of filter assembly 44 according to one
embodiment. In particular, FIG. 3 shows a perspective view of filter assembly 44,
FIG. 4 shows a detailed view of one filter pocket from filter assembly 44 in FIG. 3, while FIG. 5 shows a side view of the filter pocket depicted in FIG. 4. As shown in FIGS. 3 and 5, filter assembly 44 includes a filter frame 80 constructed according to one embodiment of the present invention. Filter frame 80 mounts filter assembly 44 in filter assembly holding housing frame 42 (FIGS. 1-2). In one embodiment, filter frame 80 is made of injection molded plastic, however those skilled in the art will recognize that other materials may be used. In one embodiment, as shown in FIG. 3, filter frame 80 is rectangular and comprises a bottom portion 82, a top portion 84 and opposing side portions 86. Although not shown in FIG. 3, filter frame 80 may have a flange that is connectible with filter assembly holding frame 42 (FIGS. 1-2) to mount filter assembly 44. In this embodiment, a gasket (not shown) may be disposed around the periphery of the flange and located between filter assembly 44 and filter assembly holding frame 42 to provide an airtight seal between filter assembly 44 and filter assembly holding frame 42.
[0018] FIGS. 3-5 shows that filter assembly 44 further comprises filter pockets 90 disposed in filter frame 80 to form a prearranged shape that can take the form of a multitude of shaped-patterns. FIG. 3 shows that filter assembly 44 includes four filter pockets 90, however, those skilled in the art will recognize that more or less filter pockets can be utilized. Each filter pocket 90 comprises a pocket mouth 92 (FIG. 4) that attaches to filter frame 80 and a pocket body 94 extending longitudinally away from the pocket mouth to a closed end 96. Filter pockets 90 are attached to filter frame 80 from behind the frame so that pocket mouths 90 are in the direction of the flow of the air or gas that is to be passed through filter assembly 44 (FIG. 3). Each
filter pocket 90 may be attached to filter frame 80 in a number of well-known
approaches. For example, in one embodiment, filter pockets 90 may be placed into
cooperating portions of filter frame 80 and locked into place by fastening means that
can include clipping, latching or clamping mechanisms. Closed end 96 of filter
pocket 90 is folded back onto itself to form a tuck fold 98 that defines a first sub-filter
pocket 100 (FIGS. 4 and 5) and a second sub-filter pocket 102 (FIGS. 4 and 5) at
pocket mouth 92 (FIG. 4). As used herein, a tuck fold is a fold of the filter media
created as it is tucked or folded upon itself. As shown in FIGS. 4-5, first sub-filter
pocket 100 and second sub-filter pocket 102 each has a sub-pocket mouth 104 located
about pocket mouth 92 with sidewalls 106 (FIGS. 4-5) extending longitudinally
therefrom to form an apex 108 (FIG. 5) at closed end 96 of filter pocket 90.
[0019] Filter assembly 44 further comprises supporting members 110 (FIG. 3) that
support filter pockets 90 within filter frame 80. As shown in FIGS. 3-4, each
supporting member 110 is located about a tuck fold 98 to support a filter pocket 90.
Supporting members 110 may include any one of a number of supporting mechanisms
that can provide support for each filter pocket 90 and their respective first sub-filter
pocket 100 and second sub-filter pocket 102, so that the filter pockets do not unfold.
A non-exhaustive listing of supporting mechanisms that can be used as supporting
member includes cylinders, rods, bars, extrusions, etc. In one embodiment, each
supporting member 110 extends vertically from bottom portion 82 of filter frame 80
to top portion 84 of filter frame 80 (FIG. 3). In one embodiment, each supporting
member 110 is located in front of a tuck fold 98 of a filter pocket 90.
[0020] As shown in FIG. 4, there is at least one attachment region 112 that is
configured to receive and support at least one supporting member 110. Attachment
region 112 may include any one of a number of fastening mechanisms that can be
used to fasten or attach tuck folds 98 to supporting members 110, in order to provide
enough support to prevent the pockets from unfolding. A non-exhaustive listing of
fastening mechanisms that can be used includes tabs, continuous tubes, loops, clips,
latches, clamps, etc. In another embodiment, supporting members 110 can be located
in back of tuck fold 98 as opposed to being in front of it. In this embodiment, at least
one attachment region 112 would be located behind tuck fold 98, so that supporting
members would be able to support filter pocket 90 and their respective first sub-filter
pocket 100 and second sub-filter pocket 102 from unfolding. In this embodiment,
each supporting member 110 would be located between opposing sidewalls 106 of
first sub-filter pocket 100 and second sub-filter pocket 102 that extend from a tuck
fold 98 of a filter pocket 90.
[0021] FIGS. 6-7 show an alternative embodiment for filter assembly 44. In
particular, FIG. 6 shows a front elevation view of a filter assembly that takes the form
of a matrix, while FIG. 7 shows a top view of the filter assembly depicted in FIG. 6.
As shown in FIG. 6, filter frame 80 is partitioned into a matrix 114 having a plurality
of rows 116 and columns 118. Each row 116 and column 118 is configured to receive
a predetermined number of filter pockets 90. In this embodiment, filter frame 80 may
be made of injection molded plastic, however those skilled in the art will recognize
that other materials may be used. In this embodiment, each filter pocket 90 located in
a row 116 and column 118 of matrix 114 is separate and distinct from each other. In
this embodiment, there are supporting members 110 that include horizontally
extending supporting members that extend across side portions 86 of filter frame 80
and vertically extending supporting members that extend vertically from bottom
portion 82 of filter frame 80 to top portion 84 of filter frame 80. In one embodiment,
each horizontally extending supporting member 110 and each vertically extending
supporting member 110 maintains at least one filter pocket 90 centered within a
respective row 116 and column 118 of matrix 114. The supporting members 110 may
include one vertical supporting member and one horizontal supporting member per
each filter pocket 90 in a row 116 and column 118 of matrix 114. In another
embodiment, there may be one horizontal supporting member for all of the filter
pockets in a row 116 and one vertical supporting member for all of the filter pockets
in a column 118. A non-exhaustive listing of supporting mechanisms that can be used
as supporting members 110 for the horizontal and vertical supporting member
includes cylinders, rods, extrusions, etc.
[0022] Although not shown in FIGS. 6 and 7, this embodiment would have
attachment regions 112 (FIG. 4) that are configured to receive the supporting member
110. In this embodiment, the attachment regions may include any one of a number of
fastening mechanisms that can be used to fasten tuck folds 98 to supporting members
110 which will provide enough support to prevent the pockets from unfolding within
matrix 114. A non-exhaustive listing of fastening mechanisms that can be used
includes tabs, continuous tubes, loops, clips, latches, clamps, etc. Attachment region
112 and accompanying fastening mechanisms can be located in front of or behind
tuck fold 98 in order to support filter pockets 90 and their respective first sub-filter
pockets 100 and second sub-filter pockets 102, and prevent them from unfolding
within matrix 114.
[0023] The various embodiments of filter assembly 44 described herein with
respect to FIGS. 3-7 may be manufactured according to one of many well-known
filter assembly fabrication techniques. For example, filter pockets 90 may be formed
from a continuous sheet of porous filtering material with top and bottom edges joined
to form pockets 90 and sub-pockets 100 and 102, having apices therebetween pockets
in a common plane with filter frame 80. Such an arrangement may be made by
bending or folding the continuous sheet of filtering material to an adjacent side of a
pocket element and fixing edges and then folding each of the pockets in on itself to
form sub-pockets 100 and 102. Pockets 90 and sub-pockets 100 and 102 may be
formed by using any well-known technique such as, for example, spot welding,
stitching, ultrasound or other means as is known in the art Alternatively, the
individual filter pockets 90 and their respective sub-filter pockets 100 and 102 can be
manufactured individually prior to mounting with filter frame 80. This can be
achieved by cutting a sheet of filtering material to size. In one embodiment, the cut
sheet of filtering material is folded in half and the overlapping side edges are stitched
or welded together. This pocket then would be folded in on itself towards pocket
mouth 92 to form sub-filter pockets 100 and 102. Edges of sub-filter pockets 100 and
102 could then be stitched or welded together.
[0024] It should be apparent that the various embodiments of the present invention
result in a filter assembly having filter pockets that are compact and have more
surface area than a filter pocket that does not have the aforementioned sub-filter
pockets. For example, the surface area of a typical filter assembly constructed from
filter pockets having a length L and height H would be equal to [2 x L x H] x the
number of pockets in the assembly, whereas the surface area of filter assembly 44
constructed from filter pockets 90 having sub-filter pockets 100 and 102 would be
equal to [4 x L xH] x the number of pockets in the assembly. Thus, filter assembly 44
according to the various embodiments of the present invention would have twice the
surface area of conventional filter pocket assemblies, which correlates to improved dust loading and longer life, as well as lower pressure drop across the filter assembly without having to change the space used by the assembly. Because filter assembly 44 according to the various embodiments of the present invention would have more compact filter pockets, these assemblies could fit into more compact filter housings, and thus provide filter assembly manufacturers with potentially more applications of use (e.g., ventilation and separation).
[0025] While the disclosure has been particularly shown and described in conjunction with a preferred embodiment thereof, it will be appreciated that variations and modifications will occur to those skilled in the art. Therefore, it is to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the disclosure.

WE CLAIM:
1. A filter assembly (44), comprising:
a filter frame (80);
a plurality of filter pockets (90) disposed in the filter frame (80), each of the plurality of filter pockets (90) comprising a pocket mouth (92) that attaches to the filter frame (80) and a pocket body (94) extending longitudinally away from the pocket mouth (92) to a closed end (96), wherein the closed end (96) is folded back onto itself to form a tuck fold (98) that defines a first sub-filter pocket (100) and a second sub-filter pocket (102) at the pocket mouth (92), the first sub-filter pocket (100) and the second sub-filter pocket (102) each having a sub-pocket mouth (104) located about the pocket mouth (92) with sidewalls (106) extending longitudinally therefrom to form an apex (108) at the closed end of the filter pocket (90), the first sub-filter pocket (100) separated from the second sub-filter pocket (102) by the tuck fold (98); and
a plurality of supporting members (110) that support the plurality of filter pockets (90) within the filter frame (80), wherein each of the plurality of supporting members (110) is located about a tuck fold (98) to support at least one of the plurality of filter pockets (90).
2. The filter assembly (44) according to claim 1, wherein each of the plurality of supporting members (110) is located in front of the tuck fold (98) of at least one of the plurality of filter pockets (90).
3. The filter assembly (44) according to claim 2, wherein each of the
plurality of supporting members (110) comprises at least one attachment region (112)
that is configured to receive at least one supporting member (110).
4. The filter assembly (44) according to claim 1, wherein the filter frame (80) is partitioned into a matrix (114) having a plurality of rows (116) and columns (118), each of the plurality of rows (116) and columns (118) configured to receive a predetermined number of the plurality of filter pockets (90).
5. The filter assembly (44) according to claim 4, wherein each of the plurality of filter pockets (90) located in a row (116) and column (118) of the matrix (114) is separate and distinct from each other.
6. The filter assembly (44) according to claim 4, wherein the plurality of supporting members (110) comprises horizontally extending supporting members (110) that extend across side portions (86) of the filter frame (80) and vertically extending supporting members (110) that extend vertically from a bottom portion (82) of the filter frame (80) to a top portion (84) of the filter frame (80).
7. The filter assembly (44) according to claim 6, wherein each horizontally extending supporting member (110) and each vertically extending supporting member (110) maintains at least one filter pocket (90) centered within a respective row (116) and column (118) of the matrix (114).
8. A filter pocket arrangement (44), comprising:
a filter frame (80);
a plurality of filter pockets (90) disposed in the filter frame (80), each of the plurality of filter pockets (90) comprising a pocket mouth (92) that attaches to the filter frame (80) and a pocket body (94) extending longitudinally away from the pocket mouth (92) to a closed end (96), wherein the closed end (96) is folded back inward towards the pocket mouth (92) to form a tuck fold (98) that defines a first sub-filter pocket (100) and a second sub-filter pocket (102) at the pocket mouth (92), the
first sub-filter pocket (100) and the second sub-filter pocket (102) each having a sub-pocket mouth (104) that coincides with a portion of the pocket mouth (92), with sidewalls (106) extending longitudinally therefrom to form an apex (108) at the closed end (96) of the filter pocket (90), the first sub-filter pocket (100) separated from the second sub-filter pocket (102) by the tuck fold (98); and
a plurality of supporting members (110) that support the plurality of filter pockets (90) within the filter frame (80), wherein each of the plurality of supporting members (110) is located at the tuck fold (98) of at least one of the plurality of filter pockets (90).
9. The filter arrangement (44) according to claim 8, wherein each of the plurality of supporting members (110) extends vertically from a bottom portion (82) of the filter frame (80) to a top portion (84) of the filter frame (80).
10. The filter arrangement (44) according to claim 8, wherein the filter frame (80) is partitioned into a matrix (114) having a plurality of rows (116) and columns (118), each of the plurality of rows (116) and columns (118) configured to receive a predetermined number of the plurality of filter pockets (90).

11. A filter assembly, substantially as herein described with reference to accompanying drawings and example.
12. A filter pocket arrangement, substantially as herein described with reference to accompanying drawings and example.