U.S. patent application number 11/346636 was filed with the patent office on 2006-08-03 for thermal auto-change air diffuser.
This patent application is currently assigned to Air System Components, L.P.. Invention is credited to David A. Gau, Gary A. Minor.
Application Number | 20060172694 11/346636 |
Document ID | / |
Family ID | 36757241 |
Filed Date | 2006-08-03 |
United States Patent
Application |
20060172694 |
Kind Code |
A1 |
Gau; David A. ; et
al. |
August 3, 2006 |
Thermal auto-change air diffuser
Abstract
An actuator for a diffuser in a fluid distribution system is
disclosed in which the actuator includes a shape memory alloy wire.
The shape memory alloy wire cooperates with at least one diffuser
blade to automatically change the flow pattern from the diffuser
based on the temperature of the fluid provided to the diffuser.
Also disclosed is a diffuser and a fluid distribution system
including this actuator.
Inventors: |
Gau; David A.; (Allen,
TX) ; Minor; Gary A.; (Coppell, TX) |
Correspondence
Address: |
CALFEE HALTER & GRISWOLD, LLP
800 SUPERIOR AVENUE
SUITE 1400
CLEVELAND
OH
44114
US
|
Assignee: |
Air System Components, L.P.
|
Family ID: |
36757241 |
Appl. No.: |
11/346636 |
Filed: |
February 3, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60649712 |
Feb 3, 2005 |
|
|
|
Current U.S.
Class: |
454/333 ;
62/186 |
Current CPC
Class: |
F24F 11/76 20180101;
F24F 11/79 20180101; F24F 13/1426 20130101; F24F 2013/146 20130101;
F24F 2013/144 20130101 |
Class at
Publication: |
454/333 ;
062/186 |
International
Class: |
F25D 17/04 20060101
F25D017/04; F24F 13/10 20060101 F24F013/10 |
Claims
1. An actuator for use in a fluid distribution system for the
distribution of fluid in at least one selected pattern, the
actuator comprising: a. an engagement mechanism to engage at least
one blade of the fluid distribution system to position or
reposition the blade; and b. a shape memory alloy wire connected to
the engagement mechanism and capable of causing the engagement
mechanism to change position, wherein the shape memory alloy wire
is capable of expanding or contracting based on the temperature of
the fluid in the distribution system, such that when the shape
memory alloy wire contracts, the engagement mechanism is moved to a
first position and when the shape memory alloy wire expands, the
engagement mechanism is moved to a second position.
2. The actuator of claim 1, further comprising a bias apparatus in
cooperation with the engagement mechanism to cause the engagement
mechanism to return to the second position when the shape memory
wire expands.
3. The actuator of claim 2, wherein the bias apparatus comprises a
spring in cooperation with the engagement mechanism.
4. The actuator of claim 1, wherein the blade of the fluid
distribution system is a straight blade.
5. The actuator of claim 1, wherein the blade of the fluid
distribution system is a curved blade.
6. The actuator of claim 1, wherein the shape memory alloy wire
expands when the temperature of the fluid in the distribution
system decreases below a first selected temperature.
7. The actuator of claim 1, wherein the shape memory alloy wire
contracts when the temperature of the fluid in the distribution
system increases above a second selected temperature.
8. The actuator of claim 1, wherein the shape memory alloy wire
comprises nitinol, copper/zinc/aluminum, copper/aluminum/nickel,
silver/cadmium, gold/cadmium, copper/tin, copper/zinc,
indium/titanium, nickel/aluminum, iron/platinum, manganese/copper,
iron/manganese/silicon, or other nickel/titanium alloys.
9. The actuator of claim 8, wherein the shape memory alloy wire
comprises nitinol.
10. The actuator of claim 1, further comprising means for causing
the engagement mechanism to move when the shape memory alloy wire
expands.
11. A diffuser for use in a fluid distribution system for the
distribution of fluid in. at least one selected pattern,
comprising: a. at least one blade for directing the flow of fluid;
and b. at least one shape memory alloy wire in direct or indirect
cooperation with the blade and capable of causing the blade to
change position in response to a temperature change in the
fluid.
12. The diffuser of claim 11, further comprising at least one
actuator, the actuator comprising an engagement mechanism for
engaging the blade to position or reposition the blade; wherein the
shape memory alloy wire is connected to the engagement mechanism
and is capable of causing the engagement mechanism to change
position.
13. The diffuser of claim 12, wherein the shape memory alloy wire
is capable of expanding or contracting based on the temperature of
the fluid in the distribution system, such that when the shape
memory alloy wire contracts, the engagement mechanism is moved to a
first position which moves the blade to a corresponding first
position, and when the shape memory alloy wire expands, the
engagement mechanism is moved to a second position which moves the
blade to a corresponding second position.
14. The diffuser of claim 13, further comprising a bias apparatus
in cooperation with the engagement mechanism to cause the
engagement mechanism to return to the second position when the
shape memory wire expands.
15. The diffuser of claim 14, wherein the bias apparatus comprises
a spring in cooperation with the engagement mechanism.
16. The diffuser of claim 11, wherein the shape memory alloy wire
is connected directly to the blade.
17. A fluid distribution system for distributing fluid into a
space, comprising a diffuser comprising at least one blade and at
least one actuator, the actuator comprising: a. an engagement
mechanism for engaging the blade to position or reposition the
blade; and b. a shape memory alloy wire connected to the engagement
mechanism and capable of causing the engagement mechanism to change
position.
18. The system of claim 17, wherein the shape memory alloy wire is
capable of expanding or contracting based on the temperature of the
fluid in the distribution system, such that when the shape memory
alloy wire contracts, the engagement mechanism is moved to a first
position which moves the blade to a corresponding first position,
and when the shape memory alloy wire expands, the engagement
mechanism is moved to a second position which moves the blade to a
corresponding second position.
19. An actuator for use in a fluid distribution system for the
distribution of fluid, the actuator comprising: a. an engagement
mechanism to engage at least one blade of the fluid distribution
system to position or reposition the blade; and b. means for
automatically changing the position of the blade based on the
temperature of the fluid without manual adjustment of the position
of the blade and without an outside power source providing power to
sense temperature of the fluid or to change the position of the
blade.
20. The actuator of claim 19, wherein the means for automatically
changing the position of the blade comprises means to cause a
non-gradual change in the position of the blade.
21. The actuator of claim 19, wherein the means for automatically
changing the position of the blade comprises a shape memory alloy
wire connected to the blade or to the engagement mechanism and
capable of causing the blade to change position.
22. A method of automatically switching a diffuser between vertical
fluid flow pattern and horizontal fluid flow pattern, comprising:
a. having blade position of the diffuser biased to one of the
vertical fluid flow pattern or the horizontal fluid flow pattern;
b. sensing the temperature of the fluid with a shape memory alloy
wire; c. actuating a change of blade position to the opposite of
the bias position by the shape memory alloy wire in response to the
temperature of the fluid.
23. The method of claim 22, further comprising actuating a change
of blade position back to the bias position in response to the
temperature of the fluid.
24. The method of claim 22, wherein actuating a change of blade
position comprises changing the blade position non-gradually.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to, and the benefit under
35 U.S.C. .sctn. 119(e) of, U.S. Provisional Application 60/649,712
filed Feb. 3, 2005, titled THERMAL AUTO-CHANGE AIR DIFFUSER, which
application is hereby incorporated by reference in its
entirety.
FIELD OF THE INVENTION
[0002] The present application is directed to fluid distribution
systems, such as heating, ventilation, and air conditioning (HVAC)
systems, and, more particularly, to control of the flow of fluid,
such as air, from the distribution systems.
BACKGROUND
[0003] HVAC systems provide air or another fluid to compartments,
such as rooms, in a controlled manner to distribute the air in the
room in a particular way. This provides comfort for the occupants
of the room, for example, cooling in summer months and heating in
winter months. Often, a diffuser is provided at the outlet from the
system into the room to direct the flow of air entering the room.
The diffuser has one or more blades that direct the flow of
air.
[0004] When both heating and cooling are provided by a single
diffuser, the buoyancy effects of air potentially create a problem.
Heating air and cooling air are preferably provided to a room in
different patterns. Cold air will naturally sink and hot air will
naturally rise. Ceiling diffusers fight this problem by blowing
cold air horizontally across a ceiling and hot air vertically down
into the space. A sidewall diffuser mounted close to the floor will
blow cold air vertically up along a wall toward the ceiling and
warm air along the floor.
[0005] Some diffusers are designed to be manually adjustable to
change between heating and cooling blow patterns. Some diffusers
actively sense supply temperature and change geometry through the
use of a powered control system. Others use passive means of
actuation like bi-metallic strips or wax motors.
[0006] Changing between heating and cooling modes in an HVAC system
with a ceiling diffuser can lead to discomfort of the room's
occupants or other problems. For example, when heat is supplied to
a ceiling diffuser set for cooling (horizontal blow) and the
diffuser is not adjusted, the heated air will stay at the top of
the conditioned space due to air buoyancy effects. The room may
still feel cold due to stratification of the air. This adds to the
cost of heating a room as the heating system must run longer to
lower the stratified zone.
[0007] When cooling is supplied to a ceiling diffuser set for
heating (vertical blow) and the diffuser is not adjusted, the cold
air may blow directly onto an occupant of the space. If a diffuser
is manually adjustable and installed in a ceiling, it may be
inaccessible or difficult for most occupants to change. The
adjustments may require going into the plenum space above the
ceiling. Not all plenum spaces are accessible.
[0008] Actively adjusting diffusers with an outside energy source
(electric, pneumatic) adds to the cost of conditioning the room.
Passive methods of adjusting a diffuser are generally slow in
actuating. This may result in a room being slowly "swept" with a
curtain of air as the diffuser switches from heating to
cooling.
SUMMARY
[0009] The present invention is directed to control of the
distribution of a fluid, such as air or another gas or combination
of gases, to a compartment, such as a room, automatically, based on
sensing the temperature of the fluid in the fluid distribution
system. This is done without requiring an outside energy source or
action on the part of the room's occupants. As the temperature of
the fluid in the distribution system reaches a predetermined value,
the blades in the diffusers are automatically moved to provide the
fluid in a particular direction.
[0010] A shape memory alloy wire cooperates with at least one blade
of the diffuser to change position of the blade in response to the
temperature of the fluid. In one embodiment, the shape memory alloy
wire is connected directly or indirectly with the blade.
[0011] One exemplary embodiment of the present invention includes
an actuator. The actuator has an engagement mechanism for engaging
a blade of the diffuser, a bias apparatus connected to the
engagement mechanism, and a shape memory alloy wire connected to
the engagement mechanism. The shape memory alloy wire expands or
contracts based on the temperature of the fluid in the distribution
system, such that when the shape memory alloy wire contracts, the
engagement mechanism is moved to a first position which moves the
blade to a corresponding first position, and when the shape memory
alloy wire expands, the engagement mechanism is moved to a second
position which moves the blade to a corresponding second
position.
[0012] For example, if the temperature of the fluid in the fluid
distribution system increases past a first predetermined value, the
shape memory wire contracts. When the shape memory wire contracts,
it pulls on the engagement mechanism and moves it to a first
position. If the engagement mechanism is engaging the diffuser
blade, then the diffuser blade is moved to a corresponding first
position.
[0013] When the temperature of the fluid in the distribution system
decreases past a second predetermined value, the shape memory wire
expands and the bias apparatus pulls on the engagement mechanism
and moves it to a second position. If the engagement mechanism is
engaging the diffuser blade, then the diffuser blade is moved to a
corresponding second position.
[0014] When the diffuser blade is the second corresponding
position, the fluid is directed into the compartment in a different
direction than when the diffuser blade is in the first
corresponding position. In one embodiment, the fluid is air and the
compartment is a room.
[0015] Also disclosed is a diffuser for use in a fluid distribution
system. The diffuser includes at least one blade for directing the
flow of fluid from the distribution system, and an actuator as
described above. Also disclosed is a fluid distribution system
having one or more diffusers as described above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In the accompanying drawings, which are incorporated in and
constitute a part of this specification, embodiments of the
invention are illustrated, which, together with a general
description of the invention given above, and the detailed
description given below, serve to exemplify the principles of this
invention, wherein:
[0017] FIG. 1 is a side view illustrating an actuator exemplifying
the present invention in use with a straight blade;
[0018] FIG. 2 is a top view of the actuator of FIG. 1;
[0019] FIG. 3 is a perspective view of actuator of FIG. 1;
[0020] FIG. 4 is a perspective view illustrating a straight-bladed
diffuser exemplifying the present invention;
[0021] FIG. 5 is a cutaway side view of the diffuser of FIG. 4;
[0022] FIGS. 5A and 5B are detail views of the areas A and B,
respectively, of FIG. 5;
[0023] FIG. 6 is an end view of the diffuser of FIG. 5 illustrating
a horizontal blow configuration;
[0024] FIG. 7 is an end view of the diffuser of FIG. 5 illustrating
a vertical blow configuration;
[0025] FIG. 8 is a side view illustrating an actuator exemplifying
the present invention in use with a curved blade;
[0026] FIG. 9 is a top view of the actuator of FIG. 8;
[0027] FIG. 10 is a perspective view of actuator of FIG. 8;
[0028] FIG. 11 is an exploded perspective view of a blade assembly
such as can be used with the actuator of FIG. 8;
[0029] FIG. 12 is a perspective view of the blade assembly of FIG.
11;
[0030] FIG. 12A is a detail view of Area A of FIG. 12;
[0031] FIG. 13 is an end view of the assembly of FIG. 12;
[0032] FIG. 14 is a perspective view illustrating a curved-bladed
diffuser exemplifying the present invention;
[0033] FIG. 15 is a cutaway side view of the diffuser of FIG.
14;
[0034] FIG. 16 is an end view of the diffuser of FIG. 15
illustrating a horizontal blow configuration;
[0035] FIG. 17 is an end view of the diffuser of FIG. 15
illustrating a vertical blow configuration;
[0036] FIG. 18 is a perspective view illustrating a curved-bladed
diffuser in an aluminum extrusion frame exemplifying the present
invention;
[0037] FIG. 19 illustrates an elevation view of a typical blow
pattern in an occupied space for a ceiling diffuser exemplifying
the present invention;
[0038] FIG. 20 illustrates an elevation view of a typical blow
pattern in an occupied space for a wall diffuser exemplifying the
present invention; and
[0039] FIG. 21 illustrates a cutaway side view of an exemplary
diffuser in accordance with the present invention having a shape
memory alloy wire connected directly to a blade.
DETAILED DESCRIPTION
[0040] The present invention is directed to components of a fluid
distribution system and to a fluid distribution system. The
invention will be described in terms of the exemplary embodiments
presented herein, but is limited only by the claims. For example,
the following discussion describes the invention in terms of an air
distribution system into a room, but the dispersion and
distribution of any fluid, and not just air, into any compartment,
or an open area, may be accomplished by the present invention. The
fluid may be, for example, a gas of combination of gases other than
air.
[0041] One diffuser in accordance with the present invention
switches between a horizontal air pattern, for example, to a
vertical air pattern, for example, dependent on the temperature of
the air without any need for manual adjustment or outside energy
source. The temperature of the air is measured or sensed, for
example, at the inlet supply to the diffuser. Such a diffuser may
be used in any HVAC application where a change of air pattern
(change of diffuser geometry) is required with a corresponding
change of temperature. This can encompass residential and
commercial applications. It can be used not only with linear slot
diffusers, but with other kinds of ceiling diffusers as well. It is
also applicable to side wall diffuser applications.
[0042] The diffuser includes at least one diffuser blade and an
actuator that engages at least one diffuser blade. The diffuser
blade directs the flow of air into the room. The actuator includes
an engagement mechanism to engage the diffuser blade. The
engagement mechanism has, for example, a cam or tongs that engage
different types of diffuser blades. The actuator also includes a
bias apparatus that is part of or attached or connected, directly
or indirectly, to the engagement mechanism. The bias apparatus
includes, for example, a spring that is directly or indirectly
attached to the engagement mechanism. The bias apparatus may also
be, for example, integral with one or more elements of the
actuator, such as by weight distribution of the engagement
mechanism. The bias apparatus also includes providing an external
weight cooperating with the engagement mechanism to return the
engagement mechanism to a predetermined position. The integral or
cooperating weight responds to gravity. The bias apparatus is any
structure that tends to return the engagement mechanism to a
predetermined position when no other forces are acting to change
the position of the engagement mechanism.
[0043] The actuator further includes a wire that is at least
partially composed of a shape memory alloy (SMA). A shape memory
alloy is generally known as a metal that exhibits an almost
rubber-like flexibility and an ability to be severely deformed and
then returned to its original shape by temperature change.
[0044] The wire must have sufficient SMA to react to temperature
changes in the air in the air distribution system and produce the
actuator changes described herein. References herein to SMA wire
include wire partially composed of a SMA and wire that is
completely composed of SMA. In one embodiment, the SMA wire is
attached or connected, directly or indirectly, to the engagement
mechanism. The SMA wire cooperates, directly or indirectly, with at
least one diffuser blade to effect a change in the position of the
blade when the temperature of the fluid reaches one or more
preselected values.
[0045] Two exemplary actuator designs in which the SMA wire are
used include a straight-blade application and a curved-blade
application. The straight blade and the curved blade refer to the
shape of blades within the diffuser used to direct and control the
pattern of air distribution to the room. The straight-blade
application actuator has "tongs" that engage and rotate, for
example, a straight blade (FIGS. 1-3). The curved-blade application
actuator has a cam that pushes on and rotates a different shape of
blade (FIGS. 8-10). Other designs and applications may be employed
without departing from the spirit and scope if the invention.
[0046] FIG. 1 illustrates an exemplary actuator 10 in accordance
with the present invention. The actuator 10 includes an engagement
mechanism (tongs) 12 to engage a straight blade assembly 14 (FIG.
4). This exemplary actuator 10 also includes a bracket 16 and a
lever 18 connected to the bracket at pivot 20. The bracket 16 has a
lever stop 22 that selectively prevents the lever 18 from
pivoting.
[0047] An SMA wire 24 is connected to the engagement mechanism 12
and the lever 18. A spring 26 is connected to the engagement
mechanism 12 and the lever 18.
[0048] FIGS. 2 and 3 illustrate a top view and a perspective view,
respectively, of the exemplary actuator of FIG. 1.
[0049] In one embodiment, the engagement mechanism (tongs) 12 is
used in the actuator 10 for a straight bladed diffuser 28, as
illustrated in FIGS. 4-7. The blade 30 of the blade assembly 14 is
punched in such way as to leave a tab 32 for the engagement
mechanism 12 to engage. The blade pivots in bushings 34 in the ends
of the plenum 36. The pivot is provided by nail point pins 38.
[0050] The plenum 36 of the diffuser 28 is made from formed sheet
metal and the actuator 10 mounts to the side of the plenum 36
opposite the inlet. In the illustrated diffuser 28, the actuator 10
is mounted with rivets 40. The mounting hardware may be selected as
desired and appropriate for the specific application without
departing from the spirit and scope of the invention.
[0051] The actuator 10 is positioned in the inlet air stream in
order to realize the full effect of the supply air temperature.
There may be multiple blades 30 in any given diffuser 28, and the
blades 30 may be of any desired length. The blade 30 may be punched
at different locations depending on the length of the diffuser 28.
Multiple actuators 10 may be needed in a single diffuser 28
depending on the number of blades 30. Likewise, a single actuator
may be directly or indirectly connected to more than one blade to
change position of more than one blade simultaneously.
[0052] FIGS. 8-10 illustrate another embodiment in which the
actuator 110 is used with curved blades. The actuator 110 includes
an engagement mechanism (cam) 112 to engage a curved blade assembly
114 (FIG. 14). This exemplary actuator 110 also includes a bracket
116 and a lever 118 connected to the bracket at pivot 120. The
bracket 116 has a lever stop 122 that selectively prevents the
lever 118 from pivoting.
[0053] An SMA wire 124 is connected to the engagement mechanism 112
and the lever 118. A spring 126 is connected to the engagement
mechanism 112 and the lever 118.
[0054] FIGS. 9 and 10 illustrate a top view and a perspective view,
respectively, of the exemplary actuator of FIG. 8.
[0055] The engagement mechanism (cam) 112 is used with a curved
blade assembly 114, as illustrated in FIGS. 11-13. The blade
assembly 114 includes a support bar 144 to which two blades 130 are
clipped with clip 146. The blades 130 can swivel in the clip 146.
On the bottom side of the support bar 144, at least one spreader
spring 148 is fastened. The spreader spring 148 keeps the blades
130 spread out. The cam engagement mechanism 112 mounts to the top
of the support bar 144 and has a tab 132 that holds one of the
blades 130 in the "down" position. As the engagement mechanism 112
actuates, it moves the other blade 130 down while the spreader
spring 148 returns it to the "up" position.
[0056] In one embodiment, the engagement mechanism (cam) 112 is
used in the actuator 110 for a curved bladed diffuser 28, as
illustrated in FIGS. 14-17. The blade assembly 114 is fastened by
screws 134 in the ends of the plenum 136.
[0057] The plenum 136 of the diffuser 128 is made from formed sheet
metal and the actuator 110 mounts to the side of the plenum 136
opposite the inlet. The mounting hardware may be selected as
desired and appropriate for the specific application without
departing from the spirit and scope of the invention.
[0058] The actuator 110 is positioned in the inlet air stream in
order to realize the full effect of the supply air temperature.
There may be multiple blades 130 in any given diffuser 128, and the
blades 130 may be of any desired length. Multiple actuators 110 may
be needed in a single diffuser 128 depending on the number of blade
assemblies 114. Likewise, a single actuator may be directly or
indirectly connected to more than one blade to change position of
more than one blade simultaneously.
[0059] Another diffuser type is constructed with an aluminum
extrusion frame 150 with a sheet metal plenum 136, as illustrated
in FIG. 18. The blade assembly 114 is mounted to the aluminum frame
spacers. The plenum 136 fits over the frame 150 and is fastened to
the sides. This diffuser type may be used with the curved-blade
diffuser or the straight-blade diffuser.
[0060] When the SMA wire is exposed to cold air, it expands and the
return spring pulls the cam or tong mechanism. This moves the
diffuser blade to a first position, such as to create horizontal
blow of air. See FIGS. 6 and 16. When the SMA wire is exposed to
hot air, it contracts and pulls the cam or tong mechanism in the
opposite direction of the return spring. This moves a diffuser
blade to a second position, such as to create vertical blow of air.
See FIGS. 7 and 17. In other embodiments the expansion of the SMA
wire leads to vertical blow and contraction of the SMA wire leads
to horizontal blow. In yet other embodiments, the
expansion/contraction of the SMA wire leads to other changes in
direction of the disposition of the blade and corresponding
direction of the flow or air, for example, right/left directing of
the blow.
[0061] Exemplary resulting air distribution patterns are
illustrated in FIGS. 19 and 20. FIG. 19 illustrates exemplary air
flow patterns for a diffuser 200 in accordance with the present
invention mounted in a ceiling. FIG. 20 illustrates exemplary air
flow patterns for a diffuser 200 in accordance with the present
invention mounted in a wall.
[0062] FIG. 21 illustrates an exemplary embodiment of a diffuser
200 in which an SMA wire 202 is connected directly to a blade 204.
The SMA wire 202 may be connected directly to a plenum 206 or to a
bracket 208 or anchored in any other way to effect a change in the
position of the blade upon change of temperature of the air or
other fluid. Any biasing apparatus, such as weight distribution of
the blade 204 to respond to gravity, may be used to change the
position of the blade 204 when the SMA wire 202 expands.
[0063] The actuator in accordance with the present invention uses
the SMA wire to achieve the diffuser blade movement actuation. In
one embodiment, the wire contracts in heating mode and expands in
cooling mode. An outside energy source is not required.
[0064] The SMA wire has an internal hysteresis that is a material
property of the alloy used. For example, the normal operating
supply air temperatures for an HVAC system are 55.degree. F. in
cooling and 85.degree. F. in heating. When an SMA alloy is at a
temperature less than a first selected temperature, for example,
60.degree. F., it is at its fully expanded state. As the air
temperature increases, there is slight contraction of the material,
but at a second selected temperature, for example, 80.degree. F.,
there is a drastic contraction of the material and at any
temperature above 80.degree. F. the material will be fully
contracted. Usually, the SMA wire will change its geometry within
about 2 seconds, and preferably within about 1 second. The actual
time for the SMA wire to undergo change depends on the material
selected for the SMA wire (see below). Now as the same wire is
cooled, it does not re-expand at 80.degree. F. It only fully
expands at 60.degree. F.
[0065] This hysteresis results in the diffuser changing geometry
only when the supply air has reached a critical temperature and it
will make the change very fast. The SMA wire essentially undergoes
a prompt or non-gradual change at selected temperatures. This
enables the position of the blades in the diffuser to change
rapidly. The actual time for the blades to change position will
depend on the configuration of the diffuser and the direct or
indirect connection between the SMA wire and the blade. This stops
drafts on occupants in the room and avoids gradual sweeping of a
curtain of air across room occupants.
[0066] In one embodiment, the material selected for the SMA wire is
nitinol. Other SMA alloys may be used and may be selected to
provide different temperature actuation ranges, based on
availability, or for any other reason without departing from the
spirit and scope of the invention. Other SMA alloys include
copper/zinc/aluminum, copper/aluminum/nickel, silver/cadmium,
gold/cadmium, copper/tin, copper/zinc, indium/titanium,
nickel/aluminum, iron/platinum, manganese/copper,
iron/manganese/silicon, and other nickel/titanium alloys. SMA
alloys are sold, for example, under the brand names Muscle
Wires.RTM., Flexinol.RTM., and BioMetal.RTM., which are registered
trademarks of Mondo-tronics, Inc., Dynalloy, Inc., and Toki
Corporation, respectively.
[0067] While the present invention has been illustrated by the
above description of embodiments, and while the embodiments have
been described in some detail, it is not the intention of the
applicants to restrict or in any way limit the scope of the
invention to such detail. Additional advantages and modifications
will readily appear to those skilled in the art. Therefore, the
invention in its broader aspects is not limited to the specific
details, representative apparatus and methods, and illustrative
examples shown and described. Accordingly, departures may be made
from such details without departing from the spirit or scope of the
applicants' general or inventive concept.
* * * * *