U.S. patent application number 16/655865 was filed with the patent office on 2020-02-13 for collapsable v-bank filter.
This patent application is currently assigned to 3M Innovative Properties Company. The applicant listed for this patent is 3M INNOVATIVE PROPERTIES COMPANY. Invention is credited to Christopher T. Gasman, Rajesh K. Katare, Kenneth J. Snider.
Application Number | 20200047101 16/655865 |
Document ID | / |
Family ID | 57320228 |
Filed Date | 2020-02-13 |
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United States Patent
Application |
20200047101 |
Kind Code |
A1 |
Katare; Rajesh K. ; et
al. |
February 13, 2020 |
COLLAPSABLE V-BANK FILTER
Abstract
A V-bank filter having a plurality of filter panels having a
first side end opposed to a second side end, the plurality of
filter panels arranged into one or more V-configurations, and a
first flexible side panel joined to the first side ends and a
second flexible side panel joined to the second side ends. The
V-bank filter having an operating position having a distance, O,
between individual filter panels measured at an open end of the one
or more V-configurations when in the operating position and a
collapsed position having a distance, C, between individual filter
panels measured at the open end when in the collapsed position. The
distance C is less than the distance O when the V-bank filter is
placed into the collapsed position and the plurality of filters
panels can be moved between the collapsed position and the
operating position while maintaining a substantially air tight
connection between the plurality of filter panels and the first
flexible side panel and while maintaining a substantially air tight
connection between the plurality of filter panels and the second
flexible side panel.
Inventors: |
Katare; Rajesh K.; (Cottage
Grove, MN) ; Gasman; Christopher T.; (New Richmond,
WI) ; Snider; Kenneth J.; (Woodbury, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
3M INNOVATIVE PROPERTIES COMPANY |
St. Paul |
MN |
US |
|
|
Assignee: |
3M Innovative Properties
Company
|
Family ID: |
57320228 |
Appl. No.: |
16/655865 |
Filed: |
October 17, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15560801 |
Sep 22, 2017 |
10486094 |
|
|
PCT/US2016/030551 |
May 3, 2016 |
|
|
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16655865 |
|
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|
62162042 |
May 15, 2015 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01D 2265/04 20130101;
B01D 46/125 20130101; B01D 46/0016 20130101; B01D 46/521
20130101 |
International
Class: |
B01D 46/00 20060101
B01D046/00; B01D 46/12 20060101 B01D046/12; B01D 46/52 20060101
B01D046/52 |
Claims
1. A V-bank filter comprising: a plurality of individual filter
panels having a first side end opposed to a second side end, the
plurality of individual filter panels arranged into one or more
V-configurations, a first side panel joined to the first side ends
by a thermoplastic weld, and a second side panel joined to the
second side ends by a thermoplastic weld forming the V-bank
filter.
2. The V-bank filter of claim 1 wherein adjacent filters panels in
the plurality of individual filter panels are joined to each other
by endcaps thermoplastically welded to the individual filter
panels.
3. The V-bank filter of claim 1 wherein the first side panel, the
second side panel, and the endcaps comprise polypropylene,
polyethylene, polyester, polyvinylchloride, chlorinated
polyvinylchloride or polyvinylidenefluoride.
4. The V-bank filter of claim 1 wherein the first side panel, the
second side panel, or the endcaps comprise an inner layer of a
thermoplastic material and an outer layer of a nonwoven material
thermoplastically welded to the inner layer.
5. The V-bank filter of claim 4 wherein the thermoplastic material
comprises polyethylene film.
6. The V-bank filter of claim 5 wherein the wherein the
polyethylene film is between 5 to 30 mils thick.
7. The V-bank filter of claim 4 wherein the nonwoven material
comprises polyester.
8. The V-bank filter of claim 7 wherein the nonwoven material
comprises 3-10 mil polyester.
9. The V-bank filter of claim 4 wherein the thermoplastic material
comprises 5-30 mil polyethylene and the nonwoven material comprises
3-10 mil polyester.
10. The V-bank filter of claim 1 wherein the first flexible side
panel and the second flexible side panel extend past an upper
surface of the plurality of individual filter panels forming a
flexible flange.
11. The V-bank filter of claim 10 wherein a first end cap applied
to a first outer filter panel and a second end cap applied to a
second outer filter panel both extend from each filter panel
forming a flexible flange.
12. The V-bank filter of claim 11 wherein the flexible flanges are
disposed into a groove in a frame and held within the groove by an
elastomeric member.
13. The V-bank filter of claim 12 wherein the elastomeric member
extends further than a depth of the groove thereby forming a
sealing surface extending from the frame for sealing the V-bank
filter to an air intake housing.
14. The V-bank filter of claim 13 wherein the elastomeric member
has a circular cross section prior to installation in the groove
and an hourglass cross section after installation in the
groove.
15. The V-bank filter of claim 1 wherein the first flexible side
panel or the second flexible side panel comprise a structural
weakening element.
16. The V-bank filter element of claim 15 wherein the structural
weakening element comprises a slit, a cutout, an aperture, a
perforation, a score line, a fold line, or pleats.
17. A method of making the V-bank filter of claim 1 comprising:
placing the plurality of individual filter panels in a fixture to
hold them in the one or more V-shaped configurations; placing the
first side panel into the fixture adjacent the first side edges of
the plurality of individual filter panels, and placing the second
side panel into the fixture adjacent the second side edges of the
plurality of individual filter panels; clamping the first side
panel and the second side panel between opposing heated platens;
heating the first side panel and the second side panel to join them
to the first and second side edges of the plurality of individual
filter elements; removing the opposing heated platens; and removing
the V-bank filter from the fixture.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of pending
prior application Ser. No. 15/560,801, filed Sep. 22, 2017, which
is a national stage filing of PCT/US2016/030551, filed May 3, 2016,
which claims benefit of Provisional Patent Application No.
62/162,042, filed May 15, 2015, the disclosures of which are
incorporated by reference in their entirety herein.
BACKGROUND
[0002] V-bank filters having one or more pleated panels oriented in
a V-configuration are known. Typically, the pleated panels are
disposed into a rigid frame made of metal or plastic that maintains
the pleated panels in a fixed configuration. The V-bank filters are
shipped from the factory with the pleated panels arranged into the
fixed V-configuration.
SUMMARY
[0003] V-bank filters are bulky with a large amount of space
present between the pleated panels in the V-bank filter. Shipping
costs can be quite large and uneconomical; especially, if the
V-bank filters are made in one country and then shipped into
another country. Therefore, what is needed is a collapsible V-bank
filter such that the V-bank filters can be shipped in the collapsed
position to minimize shipping expenses and then expanded into the
operating position for installation into an HVAC system. While it
is possible to ship individual panels and rigid framing for
assembly into a V-bank filter, typically forming an airtight
connection between the individual filter panels is difficult,
cumbersome, time consuming, or expensive. Therefore, a collapsible
V-bank filter having the pleated filter panels already joined to
each other is needed.
[0004] One method of achieving such a filter is to use flexible
side panels that in one embodiment comprise a thermoplastic
material such that they can be thermoplastically welded or
ultrasonically bonded to the pleated filter panels. In a similar
manner, the individual filter panels can be joined to each other by
a flexible thermoplastic end cap that can be welded or
ultrasonically bonded to the filter panels.
[0005] As such, the resulting V-bank filters can be changed from
the operating position where the filter panels are arranged into
one or more V-configurations, compressed into a collapsed position
where the filter panels are substantially parallel to each other
for shipping, and then expanded back into the operating
position.
[0006] Hence, in one embodiment, the invention resides in a V-bank
filter including a plurality of filter panels having a first side
end opposed to a second side end, the plurality of filter panels
arranged into one or more V-shaped configurations, a first flexible
side panel joined to the first side ends and a second flexible side
panel joined to the second side ends, and wherein the plurality of
filter panels in the one or more V-shaped configurations comprises
an operating position; a collapsed position wherein a distance, C,
between individual filter panels at an open end in the collapsed
position is less than a distance, O, between individual filter
panels at the open end in the operating position; and wherein the
plurality of filters panels can be moved between the collapsed
position and the operating position while maintaining a
substantially air tight connection between the plurality of filter
panels and the first flexible side panel and while maintaining a
substantially air tight connection between the plurality of filter
panels and the second flexible side panel.
[0007] In another embodiment the invention resides in a V-bank
filter including a plurality of filter panels having a first side
end opposed to a second side end, the plurality of filter panels
arranged into one or more V-shaped configurations, a first side
panel joined to the first side ends, and a second side panel joined
to the second side ends by a thermoplastic weld.
[0008] In another embodiment the invention resides in a method of
making the V-bank filter including placing the plurality of filter
panels in a fixture to hold them in the one or more V-shaped
configurations; placing the first side panel into the fixture
adjacent the first side edges of the plurality of filter panels,
and placing the second side panel into the fixture adjacent the
second side edges; clamping the first side panel and the second
side panel between opposing heated platens; heating the first side
panel and the second side panel to join them to the first and
second side edges of the plurality of filter elements; removing the
opposing heated platens; and removing the V-bank filter from the
fixture.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 illustrates a V-bank filter in an operating position
enabling airflow to move through the V-bank filter
[0010] FIG. 2 illustrates the V-bank filter of FIG. 1 in a
collapsed position
[0011] FIG. 3 illustrates the V-bank filter of FIG. 2 being placed
into a carton
[0012] FIG. 4 illustrates a frame for holding the V-bank filter of
FIG. 1
[0013] FIG. 5 illustrates a cross section of the frame of FIG. 4
taken at 5-5
[0014] FIG. 6 illustrates a partial cross section of the V-bank
filter of FIG. 1 taken at 6-6
[0015] FIG. 7 illustrates a method for making a V-bank Filter
DETAILED DESCRIPTION
[0016] Referring now to FIG. 1, a V-bank filter 10 includes a
plurality of filter panels 12 having a first side end 14 opposed to
a second side end 16 with the plurality of filter panels arranged
into one or more V-configurations 18. A first flexible side panel
20 is joined to the first side ends 14 and a second flexible side
panel 22 is joined to the second side ends 16. The V-bank filter of
FIG. 1 is shown in an operating position 24 having a distance, O,
between the center lines of individual filter panels 12 measured at
an open end 26 of the one or more V-configurations 18 when in the
operating position. An arrow illustrates 28 the airflow through the
V-bank filter when in the operating position.
[0017] Referring now to FIG. 2, the V-bank filter has a collapsed
position 30 having a distance, C, between center lines of the
individual filter panels 12 measured at the open end when in the
collapsed position. As seen the distance C is less than the
distance O when the V-bank filter is placed into the collapsed
position. Referring now back to FIG. 1, the plurality of filters
panels can be moved between the collapsed position (FIG. 2) and the
operating position while maintaining a substantially air tight
connection between the plurality of filter panels 12 and the first
flexible side panel 20 and while maintaining a substantially air
tight connection between the plurality of filter panels 12 and the
second flexible side panel 22.
[0018] FIG. 2 shows The V-bank filter of FIG. 1 in a fully
collapsed position wherein the plurality of filter panels 12 are
substantially parallel to each other in the collapsed position and
there is no longer an open end 26 present between adjacent filter
panels. However, there no requirement to fully collapse the
structure and the distance C, in the collapsed position, can be
less than or equal to 75% of O, 50% of O, or 25% of O.
[0019] In one embodiment, the dimensions of a standard trapezoidal
V-bank filter were 22.25 in. length by 22.25 in. width at the top
open end by 12 in. height by 17.25 in. length at lower downstream
end when in the operating position (FIG. 1). This filter had a
distance O of approximately 5.25 in. and a calculated volume of
5273 cubic inches. (V=1/2*h*(l+b)*w where h=12 in., l=22.25 in.,
b=17.25 in. and w=22.25 in.) A single V-bank filter of this size is
typically shipped in a 24 in..times.24 in..times.12 in. carton
having a volume of 6912 cubic inches.
[0020] The same sized V-bank filter in the fully collapsed position
(FIG. 2, C approximately 1.5 in.; FIG. 1, O approximately 5.25
in.), reduces to the size of a trapezoidal shape of 22.25 in. width
by 7.5 in. length at top open end by 12 in. height by 6 in. length
at lower downstream end. The collapsed filter is slightly
trapezoidal since the pleated filer panels are partially nested at
the joints which varies the distance C for the interior filter
panel spacing from 1.5 in. for the six central panels to 1.25 in.
for the outer two panels that are not nested with another panel at
the filter's top. This shape will have total volume of 1883 cubic
inches (V=1/2 *12*(7.5+6)*23.25) and three of these filters can be
shipped in the standard 24 in..times.24 in..times.12 in. carton
with enough spare room included for the frame parts to complete the
on-site assembly. Thus, for nominally the same shipping cost, three
times as many collapsible V-bank filters can be shipped as opposed
to using non-collapsible V-bank filters of the same size.
Additionally, there is a significant saving in the corresponding
packaging materials for cartons and sealing tape.
[0021] Referring now to FIG. 3, a restraining member 38 can be used
to hold the V-bank filter in the collapsed position. In at least
some embodiments, depending on the material used for the flexible
side panels (20, 22), the V-bank filter 10 will not stay in the
collapsed position shown in FIG. 2 and the V-bank filter at least
partially springs open into the operating position shown in FIG. 1
and may fully open into the operating position after removing the
force used to collapse the structure. The restraining member can be
a band surrounding and securing the V-bank filter in the collapsed
position. Alternatively, the restraining member can be a box or
carton 40, with or without the band securing the V-bank filter in
the collapsed position. Other suitable restraining members include
tape, bags, shrink wrap, clips, and other general packaging
supplies.
[0022] The filter panels may be pleated as shown or instead may be
left un-pleated. Suitable materials for making the filter panels
are known to those of skill in the art depending on the specific
application and the expected type and level of containments. The
filter panels may be single ply or multi-ply construction and
utilize a stiffer layer for pleating and another layer for
filtering. Suitable filter materials include nonwoven webs of
thermoplastics (polypropylene, nylon, polyester, acrylics, etc.),
paper, glass/carbon fibers, metal wool and/or ceramic fibers. The
filter panels could also contain additional filtration and process
aids such as activated carbons, electric charges, anti-oxidants, or
catalysts.
[0023] In one embodiment, as best seen in FIG. 1, the adjacent
filter panels 12 at an apex 32 of the one or more V-configurations
18 can be joined to each other by flexible endcaps 34. The flexible
end caps allow for an included angle .alpha., 36, to change as the
V-bank filter is moved from the operating position to the collapsed
position. Included angle .alpha. is measured between the inlet face
of one filter to the inlet face of an immediately adjacent filter.
The included angle .alpha. in the operating position is determined
by size, shape, air and pressure drop modeling and is typically in
the range from 15 degrees to 45 degrees. The included angle .alpha.
in the collapsed position is less than the included angle .alpha.
in the operating position and can be from 40 degrees to 0 degrees,
or from 20 degrees to 0 degrees, or from 5 degrees to 0
degrees.
[0024] The flexible endcaps span the distance from one filter panel
to the next adjacent filter panel to secure them to each other and
to form an airtight connection between them. The flexible endcaps
can be flush with the faces of the filter panels as seen in FIG. 1
or they can be wrapped over the edges of the filter panels to cover
at least a portion of each filter's face. The flexible endcaps can
be flush with the first and second side ends (14, 16) or they can
be wrapped over the edges to cover at least a portion of the first
side edge 14 and at least a portion of the second side edge 16 as
seen in FIG. 1.
[0025] Instead of flexible endcaps, the plurality of filter panels
can be joined to each other by filling the apex 32 of each
V-configuration 18 with an elastomeric material to secure the
filter panels to each other, to form an airtight connection between
the filter panels, and to allow the included angle .alpha. between
the filter panels to decrease as the structure is at least
partially collapsed. Suitable elastomeric materials include
thermoplastics such as polypropylene, polyester, acrylics, and
other flexible plastic substances with adhesive properties.
[0026] In one embodiment for the V-bank filter 10, the first
flexible side panel 20, the second flexible side panel 22, or the
flexible endcaps 34 were made from a thermoplastic material
thermoplastically welded to the plurality of filter panels. The
thermoplastic material may include, polyethylene film,
polypropylene, polyester, polyvinylchloride, chlorinated
polyvinylchloride, polyvinylidenefluoride, or acetyl. In one
embodiment, the thermoplastic material was between 5 to 30 mils
thick. In one specific embodiment, the polyethylene film was
between 5 to 30 mils thick.
[0027] Referring now to FIG. 6, in one embodiment for the V-bank
filter 10 the first flexible side panel 20, the second flexible
side panel 22, or the flexible endcaps 34 were made from an inner
layer 42 of a thermoplastic material thermoplastically welded to
the plurality of filter panels 12 and an outer layer 44 of a
nonwoven material thermoplastically welded to the inner layer 42.
The inner layer thermoplastic material may include, polyethylene
film, polypropylene, polyester, polyvinylchloride, chlorinated
polyvinylchloride, polyvinylidenefluoride, or acetyl. In one
embodiment, the thermoplastic material was between 5 to 30 mils
thick. In one specific embodiment, the polyethylene film was used
between 5 to 30 mils thick. The outer layer nonwoven material may
include polyester and other thermoplastics such as nylon,
glass/carbon fiber, and fluoropolymers. In one embodiment the outer
nonwoven layer was between 3-10 mils thick. In one specific
embodiment the outer layer was polyester between 3-10 mils
thick.
[0028] The bend radius is defined as the minimum inside radius of
curvature for a 1 inch strip (2.54 cm) of the flexible side panel
or the flexible endcap wrapped around a circular cross section that
the strip can be bent to without kinking or damaging the material.
In various embodiments of the invention, the bend radius for the
first flexible side panel 20, the second flexible side panel 22, or
the flexible endcaps 34 can be less than or equal to 2.0 inches,
less than or equal to 1.0 inches, or less than or equal to 0.5
inches and greater than 0.01 inches.
[0029] Referring to FIG. 1, the flexible side panels (20, 22) can
include optional structural weakening elements to make the V-bank
filter easier to collapse. The structural weakening elements can
include slits or cutouts 46, apertures or perforations 48, score
lines or fold lines 50, or pleats, or combinations thereof. Some of
the structural weakening elements (slits, cutouts, perforations,
and apertures) allow for airflow to pass through the flexible side
panels and can reduce the total pressure drop of the V-bank filter
in operation. These features need to be located in portions of the
flexible side panels after the incoming airflow has passed through
one of the filter panels as shown.
[0030] In some embodiments, as seen in FIG. 1, the first flexible
side panel 20 and the second flexible side panel 22 extend past an
upper surface of the plurality of filter panels forming a flange
52. Alternatively or in combination with extending the side panels,
the first endcap applied to the first outer filter panel and the
second endcap applied to the second outer filter panel can extend
from each filter panel forming the flange 52. In some embodiments,
a flange 52 will surround the open end 26 on all four sides as
shown in FIG. 1. In some embodiments where the flexible side panels
and the flexible endcaps are made from an inner layer of a
thermoplastic material and an outer layer of a nonwoven material,
only the outer nonwoven layer is extended to form the flange.
Depending on the construction of the housing or frame the V-bank
filter is disposed into, the thickness and flexibility of the
flange can be selected to be compatible with the housing or frame
to secure the V-bank filter during operation.
[0031] Referring now to FIG. 4, the V-bank filter of FIG. 1 is
disposed into a frame 52. Referring to the cross section taken at
5-5 of FIG. 4 and illustrated in FIG. 5, the frame 52 can have a
generally rectangular cross section 54 with a groove 56. The groove
56 can have a generally circular cross section that extends for
more than 1/2 the diameter of the circle to squeeze, pinch, and/or
capture an elastomeric member 58 within the groove 56 that holds
the flange 50 within the grove thereby retaining the V-bank filter
to the frame.
[0032] The elastomeric member 58 can have a circular cross section
prior to being placed into the groove that is larger than the
circular cross section of the groove. As such, the elastomeric
member 58 can extend further than a depth of the groove, d, thereby
forming a sealing surface 60 extending from the frame for sealing
the V-bank filter to an air intake housing. As such, the
elastomeric member provides two functions: retaining the V-bank
filter to the frame 52 by capturing the flange 50 in the groove 56
and providing a gasket to seal the V-bank filter in use to the
housing of the HVAC system.
[0033] Depending of the relative sizes of the circular cross
sections of the groove 56 and the elastomeric member 58 prior to
installation in the groove, the elastomeric member can have a
circular cross section prior to installation in the groove 56 and
an hourglass cross section (not shown) after installation in the
groove where it is pinched by the groove 56 as it exists the groove
to form the sealing surface 60. The greater the relative difference
in size between the diameter of the groove and the larger diameter
of the elastomeric member, the more squished and hourglass in shape
the elastomeric member becomes after installation in the
groove.
[0034] Suitable materials for the frame 52 include polystyrene,
polypropylene, polyvinylchloride, acetyl, acrylonitrile butadiene
styrene, polycarbonate, polyethylene terephthalate,
glycol-modified, and fiberglass. Suitable materials for the
elastomeric member 58 include polystyrene, nitrile rubber,
fluoroelastomers, fluorinated ethylene propylene, ethylene
propylene diene monomer, silicon, and polyurethane foam.
[0035] Referring now to FIG. 7 a method of making a V-bank filter
is illustrated. At station 1 the plurality of filter panels are
placed in a fixture to hold them in the one or more V-shaped
configurations. Station 2 illustrates placing the first side panel
into the fixture adjacent the first side edges of the plurality of
filter panels, and placing the second side panel into the fixture
adjacent the second side edges. Station 2 then clamps the first
side panel and the second side panel between opposing heated
platens. Station 2 then heats the first side panel and the second
side panel to join them to the first and second side edges of the
plurality of filter elements. Optionally the process can continue
at Station 3 by placing the flexible endcaps over the apexes of the
V-configurations of the plurality of filter panels and like station
2 than clamping and heating the flexible end caps between opposing
heated platens to join the endcaps to the filter panels. At Station
4 the flange created by the extended side panels and two of the
endcaps can be disposed into the frame's groove. Optionally, the
V-bank filter can be removed at Station 4 and restrained in the
collapsed position transport and not disposed into the frame. At
Station 5, the elastomeric member can be positioned over the groove
and pushed into the groove to retain the V-bank filter in the frame
and at Station 6, the completed V-bank filter assembly can be
removed from the machine.
Examples
[0036] In one embodiment, a 40 gram per square meter (gsm)
polypropylene blown melt fiber media manufactured at 3M Company's
Aberdeen, S. Dak., plant was laminated, using a hot glue spray
laminator to a spun bond polyester scrim (90 gsm, Johns Manville,
Denver, Colo.). This two layer media was electret charged to
improve filtration efficiency.
[0037] The charged laminated media was pleated in an industrial
rotary pleater to create 1 inch (2.54 cm) pleat widths. The rotary
pleater scored the media at 1 inch (2.54 cm) intervals while
feeding it forward and then pleated the web at the scored creases.
The pleated web entered a heated zone followed by a spacing
mechanism that separated the pleats to a 5.75 mm width interval
between adjacent pleats. Several hot melt adhesive nozzles dropped
a bead of adhesive that solidified and locked in the pleat
separation spacing. The last step in the process was to cut the
pleat panels into the desired length of 22 inches (56 cm with 92
pleats) and a height of 11.25 inches (28.58 cm).
[0038] Eight of these pleat panels were used in fabricating a
24''.times.24'' (61 cm.times.61 cm) standard V-bank filter with
four V-configurations similar to FIG. 1. An operator picked two
pleated panels and interleaved them at one end and inserted them
into an assembly fixture which ensured a 22 degree included angle
.alpha. between the pleated panels. This operation was repeated
until all of the eight pleat panels were inserted into the assembly
fixture. The next step in the process was to carefully interleave
the top ends of the pleated panels and engage the separation
mechanism that held the pleated panels in position for further
processing.
[0039] For this embodiment flexible side panels and flexible
endcaps (both front and back) was prepared by laminating a 20 mil
(0.51 mm) thick low density polyethylene film to a 10 mil (0.25 mm)
thick spunbond polyester nonwoven web using a sprayed adhesive. End
caps (1.5 inch or 2.5 inch by 25 inch (38 mm or 64 mm by 640 mm))
and side panels (25'' width open end, 17.25'' width lower end, and
15'' height (635 mm, 438.2 mm, and 380 mm in trapezoid shape) were
cut out of this laminated material using template dies for further
assembly.
[0040] Five end caps were placed on the front side of the V-bank
filter (with polyethylene touching the pleated panels) on the panel
ends/joints. Two end caps at either side were wider (2.5 inches (64
mm)) to ensure that enough material was left out for the flange to
attaching the V-bank filter to a frame.
[0041] An aluminum plate heater (24 inch by 24 inch (610 mm by 610
mm)) was brought down on top of the endcaps to thermoplastically
weld them to the filter panel joints. The hot plate was pre-heated
to a temperature of 450.degree. F. (232.degree. C.) and a
temperature controller maintained this temperature throughout the
assembly process. The hot plate was kept in firm contact with the
endcaps for 30 seconds and then lifted off the fixture. The fixture
assembly was then flipped upside down to weld the remaining four
endcaps to the filter panel joints. To apply the side panel, the
fixture was rotated so the side of the filter was facing up towards
the plate heater. Edges of the end caps were folded down and a
trapezoidal side panel was placed carefully to cover the V-bank
filter side completely and the hot plate heater was engaged for
thermoplastic welding. Thirty seconds of firm contact at
450.degree. F. was used to thermoplastically weld both of the
trapezoidal side panels.
[0042] The completed V-bank filter was compressed and relaxed
several times by hand from the operating position shown in FIG. 1
to the fully collapsed position shown in FIG. 2 where the included
angle .alpha. was zero degrees and each filter panel was nominally
parallel to each other and touching. Upon removal of the
compressive force, the V-bank filter would spring open to operating
position shown in FIG. 1. All of the thermoplastic welds remained
intact and the V-bank filter was suitable for use even after being
fully collapsed.
* * * * *