U.S. patent application number 11/625567 was filed with the patent office on 2008-07-24 for fabric diffuser with programmed airflow.
This patent application is currently assigned to RITE-HITE HOLDING CORPORATION. Invention is credited to Kevin J. Gebke, Frank Heim, Nicholas L. Kaufmann, Nicolas B. Paschke, Cary Pinkalla.
Application Number | 20080176506 11/625567 |
Document ID | / |
Family ID | 39361331 |
Filed Date | 2008-07-24 |
United States Patent
Application |
20080176506 |
Kind Code |
A1 |
Gebke; Kevin J. ; et
al. |
July 24, 2008 |
FABRIC DIFFUSER WITH PROGRAMMED AIRFLOW
Abstract
An air diffuser includes a porous fabric panel having areas of
different flow coefficients. The areas' positions and their
relative flow coefficients provide a means for not only diffusing
the air but also for strategically directing the airflow in a
deliberate pattern that promotes intermixing of the air while
avoiding adverse air currents. Consequently, the porous fabric
itself provides air dispersion and airflow direction without the
need for louvers or guide vanes. In some embodiments, the fabric's
porosity is programmed by laser cutting small slits into the
fabric.
Inventors: |
Gebke; Kevin J.; (Dubuque,
IA) ; Heim; Frank; (Platteville, WI) ;
Kaufmann; Nicholas L.; (Sherrill, IA) ; Paschke;
Nicolas B.; (Mequon, WI) ; Pinkalla; Cary;
(Fox Point, WI) |
Correspondence
Address: |
HANLEY, FLIGHT & ZIMMERMAN, LLC
150 S. WACKER DRIVE, SUITE 2100
CHICAGO
IL
60606
US
|
Assignee: |
RITE-HITE HOLDING
CORPORATION
Milwaukee
WI
|
Family ID: |
39361331 |
Appl. No.: |
11/625567 |
Filed: |
January 22, 2007 |
Current U.S.
Class: |
454/284 |
Current CPC
Class: |
F24F 13/0218
20130101 |
Class at
Publication: |
454/284 |
International
Class: |
F24F 7/00 20060101
F24F007/00 |
Claims
1. An air diffuser, comprising: a back pan defining an air inlet
and a rim; and a fabric panel coupled to the back pan to help
define a plenum therebetween, the fabric panel includes a first
region and a second region that together comprise substantially all
of the fabric panel, wherein: a) the first region is of a first
area, the second region is of a second area, and an area ratio of
the first region to the second region is between one and ten, and
b) the first region has a first average flow coefficient and the
second region has a second average flow coefficient such that a
coefficient ratio of the first average flow coefficient to the
second average flow coefficient is between 0.3 and 0.9.
2. The air diffuser of claim 1, wherein the first average flow
coefficient is between 80 and 320 cubic feet per minute per square
foot of area at a pressure drop of 0.5 inches of water.
3. The air diffuser of claim 1, wherein the second average flow
coefficient is between 130 and 500 cubic feet per minute per square
foot of area at a pressure drop of 0.5 inches of water.
4. The air diffuser of claim 1, wherein the first area plus the
second area have a combined area of between 3 and 20 square
feet.
5. The air diffuser of claim 1, wherein the second area is between
1 and 5 square feet.
6. The air diffuser of claim 1, wherein the second region includes
a plurality of slits, each slit of the plurality of slits has a
length and a width, wherein the length is at least three times
greater than the width.
7. The air diffuser of claim 6, wherein the plurality of slits are
substantially parallel to each other.
8. The air diffuser of claim 1, wherein the second region is one of
a plurality of second regions, and the plurality of second regions
are spaced apart from each other.
9. The air diffuser of claim 1, wherein the rim includes a first
pair of opposite edges and a second pair of opposite edges that
make the rim generally rectangular, the fabric panel is suspended
between the first pair of opposite edges, the air diffuser further
comprises a first end panel and a second end panel that couple the
fabric panel to the second pair of opposite edges.
10. The air diffuser of claim 9, wherein the first end panel and
the second end panel are made of a fabric.
11. The air diffuser of claim 10, wherein the fabric is porous.
12. The air diffuser of claim 1, further comprising a screen
disposed within the plenum.
13. An air diffuser, comprising: a back pan defining an air inlet
and a rim; and a fabric panel having a first lateral edge and a
second lateral edge coupled to the rim to help define plenum
between the back pan and the fabric panel, wherein: a) the fabric
panel includes a first upper region, a second upper region, and a
central lower region, b) the first upper region lies along the
first lateral edge, the second upper region lies along the second
lateral edge, and the central lower region is interposed between
and adjacent to the first upper region and the second upper region,
c) the first upper region is of a first area, the second upper
region is of a second area, and the central lower region is of a
third area, d) the first upper region has a relatively high average
flow coefficient, and the central lower region has a relatively low
average flow coefficient, whereby the relatively high average flow
coefficient is greater than the relatively low average flow
coefficient.
14. The air diffuser of claim 13, wherein the first area, the
second area, and the third area have a combined area of between 3
and 20 square feet.
15. The air diffuser of claim 13, wherein the first upper region
and the second upper region include a plurality of slits, each slit
of the plurality of slits has a length and a width, wherein the
length is at least three times greater than the width.
16. The air diffuser of claim 15, wherein the plurality of slits
are substantially parallel to each other.
17. The air diffuser of claim 13, wherein the rim includes a first
pair of opposite edges and a second pair of opposite edges that
make the rim generally rectangular, the fabric panel is suspended
between the first pair of opposite edges, the air diffuser further
comprises a first end panel and a second end panel that couple the
fabric panel to the second pair of opposite edges.
18. The air diffuser of claim 17, wherein the first end panel and
the second end panel are made of a fabric.
19. The air diffuser of claim 18, wherein the fabric is porous.
20. The air diffuser of claim 13, further comprising a screen
disposed within the plenum.
21. A method of creating an air diffuser, the method comprising:
providing a fabric having a first region that is porous, wherein
the first region has a first average flow coefficient; treating the
fabric to create a second region having a second average flow
coefficient that is greater than the first average flow
coefficient; and coupling the fabric to a back pan, wherein the
back pan defines an air inlet and the fabric and the back pan help
define a plenum therebetween providing air flow to the plenum so
that air passing through the fabric is diffused while being
separated and directed by the first and second regions of different
porosity.
22. The air diffuser of claim 21, wherein the first average flow
coefficient is between 80 and 320 cubic feet per minute per square
foot at a pressure drop of 0.5 inches of water.
23. The air diffuser of claim 21, wherein the second average flow
coefficient is between 130 and 500 cubic feet per minute per square
foot at a pressure drop of 0.5 inches of water.
24. The air diffuser of claim 21, wherein the first region plus the
second region have a combined area of between 3 and 20 square
feet.
25. The air diffuser of claim 21, wherein the second region is
created by laser cutting a plurality of slits in the fabric, where
each slit of the plurality of slits has a length and a width,
wherein the length is at least three times greater than the
width.
26. The air diffuser of claim 25, wherein the plurality of slits
are substantially parallel to each other.
Description
FIELD OF THE DISCLOSURE
[0001] The patent disclosure generally pertains to discharge air
diffusers and more specifically to a fabric diffuser with
programmed airflow.
BACKGROUND OF RELATED ART
[0002] There are a wide variety of air diffusers for directing and
dispersing filtered air into a room. A diffuser's ability to
properly direct and thoroughly disperse the air is particularly
important when the diffuser serves a room that contains a fume
hood. A fume hood is an exhaust air register typically used for
drawing toxic air from a controlled workstation so that the toxic
air does not escape into the rest of the room. Air diffusers
replenish the volume of air that the fume hood draws from the room;
however, if the diffuser produces adverse air currents, the
currents of air might blow or draw the toxic air out from under the
fume hood, thereby allowing the toxic air to escape and circulate
throughout the room.
[0003] To address this problem, air diffusers often include louvers
or guide vanes to direct the airflow in certain directions. In
addition to guide vanes, porous materials have been used to evenly
disperse the air. Although the combination of guide vanes and
porous materials can provide an effective air diffuser, such a
combination of elements can add unnecessary cost to the diffuser.
Moreover, exposed guide vanes installed downstream of the porous
material can be unsightly. Alternatively, guide vanes can be
internally installed and hidden by the porous material, but then
the guide vanes can be generally inaccessible, which can make it
difficult to aim the airflow in a desired direction.
[0004] Consequently, a need exists for a simple yet effective air
diffuser that is particularly suited for critical applications.
SUMMARY
[0005] In some examples, an air diffuser includes a porous fabric
panel with areas of different porosities.
[0006] In some examples, the fabric panel has some regions with a
flow coefficient of between 80 and 320 cubic feet per minute
through an area of one square foot at a pressure drop of 0.5 inches
of water, and the panel has other regions that have a flow
coefficient of between 130 and 500.
[0007] In some examples, the regions of different flow coefficients
are adjacent each other to promote intermixing of air
therebetween.
[0008] In some examples, a ratio of the first region's average flow
coefficient to the second region's average flow coefficient is
between 0.3 and 0.9.
[0009] In some examples, a ratio of the first region's area to the
second region's area is between one and ten.
[0010] In some examples, the fabric panel covers an area of 3 to 20
square feet such as, for example, about 8 square feet.
[0011] In some examples, the second region includes a plurality of
slits each of which has a length and a width, wherein the length is
at least three times greater than the width.
[0012] In some examples, the slits are laser cut into the fabric
material by feeding the material underneath a pulsating laser.
[0013] In some examples, the slits are substantially parallel to
each other.
[0014] In some examples, the diffuser includes a screen that helps
break the velocity pressure within the diffuser.
[0015] In some examples, areas of relatively high flow coefficient
are biased toward the ceiling to encourage airflow in that
area.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a bottom view of one example of an air
diffuser.
[0017] FIG. 2 is a side view of the air diffuser of FIG. 1.
[0018] FIG. 3 is cross-sectional end view taken along line 3-3 of
FIG. 1.
[0019] FIG. 4 is an exploded view of FIG. 3.
[0020] FIG. 5 is a perspective view of a screen used in the
diffuser of FIG. 1.
[0021] FIG. 6 is a perspective view illustrating a method of
creating an air diffuser.
DETAILED DESCRIPTION
[0022] FIGS. 1-3 show an air diffuser 10 that gently ventilates a
room 12 by discharging air 14 in a strategic flow pattern. The flow
pattern promotes thorough intermixing of the air yet avoids
creating deleterious air currents within the room. Air diffuser 10
includes a fabric panel 16 with programmed porosity and other
integral features that enable panel 16 to both disperse and direct
the air without having to rely on mechanical louvers or guide vanes
to do so.
[0023] Basically, fabric panel 16 is attached to and suspended from
a back pan 18 to create a plenum 20 between the two. A blower, or
some other equivalent air mover, forces air 14 into plenum 20 via
an air inlet 22 of back pan 18. The air pressure within plenum 20
may be, for example, between 0.1 and 0.25 inches of water higher
than that within room 12 so that the air in plenum 20 forces panel
16 to bulge outward as shown in FIG. 3. To control the shape of the
diffuser 10 under pressure, diffuser 10 may include two
appropriately shaped end panels 24 that connect to fabric panel 16.
Although end panels 24 may be made of porous fabric and may be
disposed at an incline (relative to ceiling 26) as shown in FIG. 2,
end panels 24 could alternatively be disposed perpendicular to
ceiling 26, be impervious to air, and/or be made of a rigid,
non-fabric material. To evenly distribute the air pressure across
suspended panel 16, a relatively coarse screen 28 (FIG. 5) may be
added to help break the velocity pressure of the air traveling from
inlet 22 toward panel 16.
[0024] Diffuser 10 can be assembled as shown in FIG. 4. End panels
24 can be sewn or otherwise joined to fabric panel 16. To help
attach and suspend panels 16 and 24 from back pan 18, a bead 30
extends along the periphery of panels 16 and 24. Bead 30 fits
within a slot 32 in a generally rectangular frame 34, and threaded
fasteners 36 can be used to fasten frame 34 to back pan 18, thereby
clamping bead 30 between frame 34 and a rim 38 of back pan 18. To
hold screen 28 in place, additional fasteners 40 can hold four
mounting ears 42 (FIG. 5) of screen 28 to back pan 18. The
assembled diffuser 10 may have, for instance, nominal dimensions of
two feet by four feet to conveniently fit within a rectangular
opening normally meant for receiving standard size ceiling tiles.
The total area of fabric panel 16 may be between three and twenty
square feet.
[0025] To thoroughly mix and disperse air 14, the example fabric
panel 16 includes two or more discrete regions that have different
flow coefficients so that diffuser 10 releases air 14 at different
flow rates through panel 16, thereby creating an airflow with a
predetermined pattern and promoting intermixing of adjacent
airstreams. In this manner, the fabric of diffuser 10 can serve the
function of both diffusing the air passing therethrough as well as
properly separating and directing the airflow. The latter of these
functions is conventionally achieved with internal guide vanes or
louvers behind a diffuser panel. This conventional structure can be
eliminated by giving the diffuser 10 itself areas of differing
porosity to thereby separate and direct the airflow to create an
airflow of desired pattern. The areas of different porosity can be
referred to as having differing flow coefficients. The term, "flow
coefficient" refers to a volumetric flow rate through a given area
for a given pressure drop. Although the actual units for a flow
coefficient may vary, the subject disclosure will be described and
claimed using units of cubic feet per minute through an area of one
square foot for an industry-standard pressure drop of 0.5 inches of
water. The regions of different flow coefficients can be laid out
in various locations across panel 16 to program a certain airflow
pattern that provides a desired effect.
[0026] Referring to FIG. 1, in some examples, panel 16 includes a
first region 44 whose flow coefficient is determined by the
inherent porosity of the fabric material itself. Panel 16 can be a
polyester fabric with a mock leno weave that provides a flow
coefficient of 80 to 320, and for example, about 160 cubic feet per
minute per unit area at a pressure drop of 0.5 inches of water. A
second region 46; comprising areas 46a, 46b, 46c and 46d; has a
flow coefficient of 130 to 500, and for instance, about 260 cubic
feet per minute per unit area at a pressure drop of 0.5 inches of
water. To ensure thorough air dispersion, a ratio of the first
region's area to the second region's area may be between one and
ten, and a ratio of the first region's average flow coefficient to
the second region's average flow coefficient may be between 0.3 and
0.9.
[0027] Referring to FIG. 6, the additional porosity or increased
flow coefficient of region 46 can be produced in various ways
including, but not limited to, laser cutting a plurality of slits
48 into a fabric sheet 50 that can later be used for making panel
16. To create slits 48, a plurality of laser units 52 can be pulsed
on and off as sheet 50 is fed across laser beams 54. Good airflow
characteristics have been achieved, for example, when each slit is
at least three times longer than they are wide. In some cases, each
slit is about 1/8 inch long, and the slits are spaced about 1/8
inch apart end-to-end. The slits can run generally parallel to each
other and be spaced about 3/16 inches apart from side-to-side. The
slits can be grouped to provide areas 46a, 46b, 46c and 46d of
different widths. In some cases, for instance, areas 46c and 46d
are about 1.5 inches wide (dimension 56), and areas 46a and 46b are
about 1.7 inches wide (dimension 58).
[0028] Areas 46a, 46b, 46c and 46d can be positioned on panel 16 to
direct a disproportionate amount of air horizontally near ceiling
26, thus avoiding the creation of strong downward currents of air
that might disrupt the operation of a fume hood below diffuser 10.
To accomplish this, the position of areas 46a, 46b, 46c and 46d can
be biased toward a first upper region 60 and a second upper region
62 of panel 16 (FIGS. 1 and 3), wherein a central lower region 64
has a relatively low average flow coefficient and regions 60 and 62
have a relatively high average flow coefficient. Regions 60, 62 and
64 are defined as each comprising one third of panel 16, wherein
first upper region 60 lies along a first lateral edge 66 of rim 38,
second upper region 62 lies along a second lateral edge 68 of rim
38, and central lower region 64 is interposed between and adjacent
to upper regions 60 and 62.
[0029] The nearly horizontal flow at ceiling 26 may be enhanced
when panel 16 droops about 6.5 inches (dimension 70) for a two-foot
wide panel as shown in FIG. 3. It may also be helpful to have the
wider regions 46a and 46b (which are about 1.7 inches wide) close
to ceiling 26 and to have the narrower regions 46c and 46d (which
are about 1.5 inches wide) a little farther away from ceiling
26.
[0030] Although the invention is described with respect to various
examples, modifications thereto will be apparent to those of
ordinary skill in the art. For example, the porosity of the first
region need not be the same as the native porosity of the
fabric--treatment such as coating and/or perforating the material
can be used to set its porosity. The shape and location fo the
areas of different porosity could also be different than those
depicted herein--and chosen to adhieve a desired airflow patterns
or characterictics. For example, while the slits 48 shown on the
end panels 24 are parallel to those on the panel 16, they could be
perpendicular thereto or disposed at some other angle. Given that
such modification are possible without departing from inventive
concepts herein, the scope of the invention, is to be determined by
reference to the following claims:
* * * * *