Note: Descriptions are shown in the official language in which they were submitted.
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DAMPER ASSEMBLY
BACKGROUND OF THE INVENTION
This invention relates generally to damper assemblies for refrigerators, and
more particularly, to damper assemblies having noise dampening features.
Known refrigerators typically regulate a temperature of a refrigerated
compartment by opening and closing a damper door established in flow
communication with a freezer compartment. At least some known refrigerators
also
operate a fan to draw cold freezer compartment air into the refrigerated
compartment
as needed to maintain a clesired temperature in the fresh food compartment.
In known refrigerators, however, operation of the damper door may be
problematic. For example, when the damper door is moved to an open position or
a
closed position, the damper door impacts a travel stop. The noise level of the
impact
is objectionable in some known dampers. Additionally, the damper door and/or
the
travel limits may be damaged or deteriorated over time and after multiple uses
due to
the force of the impact.
BRIEF DESCRIPTION OF THE INVENTION
In one aspect, a damper assembly is provided including a housing
positionable between reffigerator compartments operable at different
temperatures. A
damper door is coupled to the housing and is movable between a first position
configured to restrict airflow between the refrigerator compartments and a
second
position configured to allow airflow between the refrigerator compartments. An
actuation device is operatively coupled to said damper door. The actuation
device is
configured to move the damper door between the first position and the second
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position during an energizing cycle, and the actuation device is configured to
be
energized intermittently during the energizing cycle.
In another aspect, a control system is provided for a damper assembly
having a damper door movable between a first position and a second position.
The
control system includes an actuation device operatively coupled to the damper
door
and configured to move the damper door between the first position and the
second
position during an energizing cycle. A controller is configured to supply
energy from
an energy source during the energizing cycle, wherein the energy is supplied
intermittently during the energizing cycle.
In a further aspect, a method is provided for operating a damper assembly
having a controller, a damper door, and an actuation device operatively
coupled to the
damper door and configured to move the damper door between a first position
and a
second position during an energizing cycle. The method includes supplying
energy
from an energy source to the actuation device during the energizing cycle, and
controlling the supply of energy from the energy source to the actuation
device by
intermittently energizing the actuation device during the energizing cycle.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of an exemplary refrigerator.
Figures 2 is a perspective view of an exemplary damper assembly for the
refrigerator shown in Figure 1.
Figures 3 is another perspective view of the damper assembly shown in
Figure 2.
Figures 4 is a further perspective view of the damper assembly shown in
Figure 2.
Figure 5 is a schematic diagram of a control system for the damper
assembly shown in Figures 2-4.
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Figure 6 is a diagram showing an exemplary operation scheme of a control
system for the damper assembly shown in Figures 2-4.
DETAILED DESCRIPTION OF THE INVENTION
Figure 1 is a perspective view of an exemplary refrigerator 100 in which
exemplary embodiments of the present invention may be practiced and for which
the
benefits of the invention may be realized. It is appreciated, however, that
the herein
described methods and. apparatus may likewise be practiced in a variety of
refrigerating appliances with modification apparent to those in the art.
Therefore,
refrigerator 100 as described and illustrated herein is for illustrative
purposes only and
is not intended to limit trie herein described methods and apparatus in any
aspect.
Figure 1 illustrates a side-by-side refrigerator 100 including a fresh food
storage compartment 102 and a freezer storage compartment 104. Freezer
compartment 104 and fresh food compartment 102 are arranged side-by-side. In
one
embodiment, refrigerator 100 is a commercially available refrigerator from
General
Electric Company, Appliance Park, Louisville, KY 40225, and is modified to
incorporate the herein described methods and apparatus.
It is contemplated, however, that the teaching of the description set forth
below is applicable to other types of refrigeration appliances, including but
not limited
to top and bottom mount refrigerators and compact refrigerators, such as
refrigerators
of the type having a single door with a freezer compartment received within a
refrigeration compartment and having a capacity of between approximately four
to six
cubic feet. The herein described methods and apparatus are therefore not
intended to
be limited to any particular type or configuration of a refrigerator, such as
refrigerator
100.
Refrigerator 100 includes multiple refrigerator compartments, such as fresh
food storage compartment 102 and freezer storage compartment 104, which are
contained within an outer case 106 and inner liners 108 and I10. The
refrigerator
compartments are operated at different temperatures. A space between case 106
and
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liners 108 and 110, and between liners 108 and 110, is filled with foamed-in-
place
insulation. Outer case 106 normally is formed by folding a sheet of a suitable
material, such as pre-painted steel, into an inverted U-shape to form top and
side walls
of case. A bottom wall of case 106 normally is formed separately and attached
to the
case side walls and to a bottom frame that provides support for refrigerator
100. Inner
liners 108 and I10 are, molded from a suitable plastic material to form
freezer
compartment 104 and fresh food compartment 102, respectively. Alternatively,
liners
108, 110 may be formed by bending and welding a sheet of a suitable metal,
such as
steel. The illustrative embodiment includes two separate liners 108, 110 as it
is a
relatively large capacity unit and separate liners add strength and are easier
to
maintain within manufacturing tolerances. In smaller refrigerators and in some
compact refrigerators, a single liner is formed and a mullion spans between
opposite
sides of the liner to divide it into a freezer compartment and a fresh food
compartment. In some compact refrigerators, a single liner is formed and a
formed
metal liner is attached within fresh food compartment to form freezer
compartment.
A breaker strip 112 extends between a case front flange and outer front
edges of liners. Breaker strip 112 is formed from a suitable resilient
material, such as
an extruded acrylo-butadiene-styrene based material (commonly referred to as
ABS).
The insulation in the space between liners 108, 110 is covered by another
strip of suitable resilient material, which also commonly is referred to as a
mullion
114. Mullion 114 also preferably is formed of an extruded ABS material.
Breaker
strip 112 and mullion 114 form a front face, and extend completely around
inner
peripheral edges of case 106 and vertically between liners 108, 110. Mullion
114,
insulation between compartments, atid a spaced wall of liners separating
compartments, sometimes are collectively referred to herein as a center
mullion wall
116.
Shelves 1] 8 and slide-out drawers 120 normally are provided in fresh food
compartment 102 to support items being stored therein. A bottom drawer or pan
122
may partly form a quick chill and thaw system (not shown) and selectively
controlled,
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together with other refrigerator features, by a microprocessor (not shown)
according
to user preference via manipulation of a control interface 124 mounted in an
upper
region of fresh food storage compartment 102 and coupled to the
microprocessor. A
shelf 126 and wire baskets 128 are also provided in freezer compartment 104.
Microprocessor is programmed to perform functions described herein, and
as used herein, the term microprocessor is not limited to just those
integrated circuits
referred to in the art as imicroprocessor, but broadly refers to computers,
processors,
microcontrollers, microcomputers, programmable logic controllers, application
specific integrated circuits, and other programmable circuits, and these terms
are used
interchangeably herein.
Freezer compartment 104 includes an automatic ice maker 129 and a
through the door water and ice dispenser 130 is provided in freezer door 132.
Ice
maker 129 includes an ice bucket 131 for storage of ice. In smaller
refrigerators and
in compact refrigerators, freezer compartment 104 may not include ice maker
129 or
ice dispenser 130.
Freezer door 132 and a fresh food door 134 close access openings to fresh
food and freezer compartments 102, 104, respectively. Each door 132, 134 is
mounted by a top hinge 136 and a bottom hinge (not shown) to rotate about its
outer
vertical edge between ai: open position, as shown in Figure 1, and a closed
position
(not shown) closing the associated storage compartment. Freezer door 132
includes a
plurality of storage shelves 138 and a sealing gasket 140, and fresh food door
134 also
includes a plurality of storage shelves 142 and a sealing gasket 144.
In accordance with known refrigerators, refrigerator 100 also includes a
machinery compartment (not shown) that at least partially contains components
for
executing a known vapor compression cycle for cooling air. The components
include
a compressor (not shown), a condenser (not shown), an expansion device (not
shown),
and an evaporator (not shown) connected in series and charged with a
refrigerant.
The evaporator is a type of heat exchanger which transfers heat from air
passing over
the evaporator to a refrigerant flowing through the evaporator, thereby
causing the
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refrigerant to vaporize. 'The cooled air is used to refrigerate one or more
refrigerator
or freezer compartments via fans (not shown). Collectively, the vapor
compression
cycle components in a refrigeration circuit, associated fans, and associated
compartments are referred to herein as a sealed system. The construction of
the
sealed system is well kmown and therefore not described in detail herein, and
the
sealed system is operable to force cold air through the refrigerator.
In the exemplary embodiment, the cooled air is used to refrigerate freezer
compartment 104, and the cooled air is supplied to fresh food compartment 102
via a
damper assembly 200 positioned between fresh food compartment 102 and freezer
compartment 104. In one embodiment, damper assembly 200 is positioned in
center
mullion wall 116. In other embodiments, damper assembly 200 is positioned in a
duct
(not shown) extending between freezer compartment 104 and fresh food
compartment
102. In one embodiment, a fan (not shown) is provided within or adjacent
damper
assembly 200 to facilitate increasing airtlow through damper assembly 200. In
one
embodiment, a heater is provided within or adjacent damper assembly 200 to
facilitate
reducing or eliminating freezing of condensation on damper assembly 200.
Damper
assembly 200 is operatecl by the microprocessor when the demand for cooling in
fresh
food compartment changes. For example, when cooling is demanded in fresh food
compartment 102, damper assembly 200 is opened and when cooling is no longer
demanded in fresh food compartment, damper assembly 200 is closed.
In an alternative embodiment, damper assembly 200 is utilized to supply
cooling airflow between other types of refrigerator compartments, such as, for
example, a fresh food compartment and a quick chill or quick thaw compartment
contained within the fresh food compartment, or a freezer compartment and a
quick
chill or quick thaw compartment contained within the freezer compartment. As
such,
damper assembly 200 is utilized to control airflow between compartments
operated at
different temperatures.
Figures 2-4 are perspective views of damper assembly 200 for refrigerator
100 shown in Figure 1. Figure 2 illustrates damper assembly 200 in a closed
position,
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wherein airflow is restricted between freezer compartment 104 and fresh food
compartment 102 (showri in Figure 1). Figure 3 illustrates damper assembly 200
in an
intermediate position, wherein some airflow is allowed between freezer
compartment
104 and fresh food compartment 102. Damper assembly 200 is positioned in the
intermediate position during operation of damper assembly 200, such as while
damper
assembly 200 is moving between the opened and closed positions. Figure 4
illustrates
damper assembly 200 in an open position, wherein airflow is allowed between
freezer
compartment 104 and fresh food compartment 102.
In the exemplary embodiment, damper assembly 200 is a sliding gate
damper. Damper assembly 200 includes a damper housing 202, a damper door 204,
and an actuation device. 206 for moving damper door 204 with respect to damper
housing 202. Damper door 204 is moveable between a first or closed position
and a
second or open position.
Damper housing 202 is fabricated from a plastic material. In one
embodiment, damper housing 202 includes a sound dampening material. Damper
housing 202 includes a front face 210 and a rear face 212. In the exemplary
embodiment, front face 210 defines a fresh food compartment side of housing
202 and
rear face 212 defines a fi-eezer compartment side of housing 210. [n one
embodiment,
front face 210 is exposed to fresh food compartment 102. Damper door 204
extends
along rear face 212, and is moveable along rear face 212 in a linear
direction, such as
in the direction of arrow A. In alternative embodiments, damper door 204 is
moveable in a different linear direction. In other alternative embodiments,
damper
door 204 is rotatable.
Damper housing 202 includes travel slots 214 extending from rear face 212.
Damper door 204 engages travel slots 214, and travel slots 214 define a range
of
motion for damper door 204 with respect to damper housing 202. Damper housing
202 includes guide members 216 that restrict movement of damper door 204 in a
direction transverse from the direction of movement of damper door 204, such
as in
the direction of arrow 13. In one embodiment, damper housing 202 includes
travel
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limits 218 positioned generally opposed from travel slots 214. Travel limits
218
define a maximum range of motion of damper door 204. When damper door 204 is
moved to either a fully open or fully closed position, damper door 204 strikes
travel
limit 218, causing an audible noise. The amount of noise caused is based on
factors
such as the velocity of damper door 204, and the force driving damper door 204
into
travel limits 218. By controlling such factors, the amount of noise may be
reduced.
In the exemplary embodiment, and as illustrated in Figure 4, damper
housing 202 includes a plurality of openings 220 for air to flow through
damper
housing 202. Openings 220 are exposed when damper door 204 is moved to the
open
position, as illustrated in Figure 4. However, openings 220 are covered when
damper
door 204 is in the closed position, as illustrated in Figure 2.
Damper door 204 includes a frame or body 230 having a plurality of
openings 232 separated by a plurality of slats 234. Frame 230 is slidably
coupled to
damper housing 202 such that openings 232 are substantially aligned with
openings
220 of housing 202 when damper door 204 is moved to the open position. When
damper door 204 is moved to the closed position, slats 234 are substantially
aligned
with openings 220 of housing 202 and restrict airflow through openings 220. In
the
exemplary embodiment, a first end 236 of frame 230 is received in travel slots
214
and a second end 238 of frame 230 is positioned between guide members 216. In
the
exemplary embodiment, a mounting member 240 extends from frame 230 proximate
second end 238. Mounting member 240 is coupled to actuation device 206 and
converts movement of actuation device 206 to damper door 204.
Actuation device 206 is fixedly coupled to damper housing 202. Actuation
device 206 includes a solenoid 250 having a plunger 252 (shown in phantom)
operatively coupled to 'mounting member 240. In the exemplary embodiment,
solenoid 250 is a dual coil solenoid configured to control linear movement of
plunger
252 in a first direction, such as in the direction of arrow C, and a second
direction,
such as in the direction of arrow D. For example, when a first or close coil
254 is
energized, plunger 252 is moved in the first direction and damper door 204 is
closed.
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When a second or open coil 256 is energized, plunger 252 is moved in the
second
direction and damper door 204 is opened. When plunger 252 is moved to either a
fully open or fully closed position, plunger 252 strikes a travel limit (not
shown),
causing an audible noise. The amount of noise caused is based on factors such
as the
velocity of plunger 252, and the force driving plunger 252 into the travel
limit. By
controlling such factors, the amount of noise may be reduced.
Figure 5 is a schematic diagram of a control system 300 for damper
assembly 200. A power source 302 is coupled to damper assembly 200 for
applying
voltage to, or energizing, solenoid 250 for an energizing cycle. Each
energizing cycle
energizes solenoid 250 for an adequate amount of time to facilitate moving
damper
door 204 to the first position or to the second position. A controller 304 is
operatively
coupled to power source: 302 for controlling the supply of power from power
source
302 to solenoid 250. For example, controller 304 may control an amount of
voltage
applied to solenoid 250 or controller may 304 control an amount of time the
voltage is
applied to solenoid 250, or controller 304 may control when the voltage is
applied to
solenoid 250. In the exemplary embodiment, each of first coil 254 and second
coil
256 receive voltage from power supply 302. Only one coil 254 or 256 is
energized at
a time for the energizing cycle. Once the energizing cycle is over, coil 254
or 256 is
de-energized and damper door 204 is either fully closed or fully opened. In
the
exemplary embodiment, controller 304 signals power source 302 to energize
solenoid
intermittently during the energizing cycle, as described below in more detail.
For
example, the controller 304 sends a pulse width modulated signal to power
source 302
to control the energization of solenoid 250. In the exemplary embodiment, the
pulse
width is increased with each successive pulse during the energizing cycle.
Figure 6 is a diagram showing an exemplary operation scheme of control
system 300 during a single energizing cycle. The diagram illustrates the
application
of voltage 350 from power supply 302 (shown in Figure 5) to solenoid 250
(shown in
Figures 2-4) over a predetermined time 352. The time illustrated in Figure 6
represents a single energizing cycle and is shown in milliseconds.
Additionally, the
diagram illustrates various voltage application times, shown generally at 354.
It is
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appreciated that the voltage, the energizing cycle and the various voltage
application
times 354 illustrated in Figure 6 are for illustrative purposes only, and are
not
intended to be limited to the voltages or times shown in Figure 6. Rather, the
voltages
and times may be more or less than the voltages or times illustrated in Figure
6.
In operation, controller 304 signals power source 302 to energize solenoid
250 intermittently during the energizing cycle. In the exemplary embodiment,
power
source 302 pulses solenoid 250 for a series of voltage application time 354
such that
solenoid 250 is not continuously energized for the entire energizing cycle.
Additionally, each voltage application time 354 is incrementally increased
during the
energizing cycle. For example, when the energizing cycle is initiated, a
voltage is
applied to solenoid 250 for a predetermined amount of time. The initial
energization
is a relatively short time period, as compared to other voltage application
times 354.
A wait time 356 is then initiated, and after a predetermined amount of time, a
second
energization is initiated. The second energization is applied for a longer
period of
time than the initial energization. Another wait time 356 is initiated. The
second wait
time may be equal to the first wait time, or the second wait time may be more
or less
than the first wait time. In the exemplary embodiment, each successive wait
time is
less than the previous wait time because each energization is initiated at
equal
intervals, such as 50 milliseconds. In the exemplary embodiment, the final
energization of solenoid 250 in each energizing cycle occurs for approximately
the
entire interval. As such, solenoid 250 provides an adequate force to overcome
a high
friction force.
In use, damper door 204 resists movement while opening or closing due to
friction. Friction exists between damper door 204 and damper housing 202.
Additionally, friction may exist based on freezing of condensation near the
interface
of damper door 204 and damper housing 202. The friction force must be overcome
to
initiate movement of damper door 204 in either the first or second directions.
Solenoid 250 forces damper door 204 to move. To overcome the friction force,
solenoid 250 is energized for a minimuin time. The minimum time varies based
on
the interaction of damper door 204 and damper housing 202 and other variables,
such
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as an amount of freezing. As such, the minimum time may be different for each
energizing cycle. By pulsing the voltage applied to solenoid 250, and by
incrementally increasing the voltage application time 354 with each successive
pulse,
the solenoid 250 eventually overcomes the friction force and initiates
movement of
damper door 204. The solenoid 250 provides an initial acceleration and
momentum to
damper door 204, and then removes the force pushing or pulling damper door 204
open or closed. As such, damper door 204 decelerates toward travel limits 218
once
voltage application time 354 is ended. Additionally, because of wait time 356,
damper door 204 is not being actively moved (i.e. pushed or pulled) toward
travel
limit 218. As such, the force that damper door 204 engages travel limits 218
is
reduced as compared to a situation wherein damper door 204 is actively being
moved
by solenoid 250 throughout the damper door 204 range of motion. Once damper
door
204 is positioned against travel limits 218, additional energization of
solenoid 250
does not cause movement of damper door 204.
A damper assembly is thus provided which functions in a cost effective and
reliable manner. The damper assembly includes a dual coil solenoid that opens
or
closes a damper door based on a control scheme from a controller. The
controller
signals a power source to pulse energy to one of the coils during an
energizing cycle
to either open or close the damper door. The duration of energization is
increased
with each successive pulse to provide a force to overcome a friction force
resisting
movement of the damper door. Because the energy supplied to the solenoid is
pulsed,
the average voltage app:l'ted is reduced, thus reducing an impact force of the
damper
door and the plunger of the solenoid at respective travel limits. As a result,
the
amount of noise from the impact is reduced as compared to damper assemblies
that
provide a continuous voltage to the solenoid.
Exemplary embodiments of damper assemblies are described above in
detail. The damper assemblies are not limited to the specific embodiments
described
herein, but rather, components of each damper assembly may be utilized
independently and separately from other components described herein. For
example,
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each damper assembly component can also be used in combination with other
damper
assembly components.
While the invention has been described in terms of various specific
embodiments, those skilled in the art will recognize that the invention can be
practiced with modification within the spirit and scope of the claims.
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