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Title:
AIR DAMPER WITH INTEGRATED HEATER
Document Type and Number:
WIPO Patent Application WO/2022/245957
Kind Code:
A1
Abstract:
An air damper unit includes a damper wall mounted between a freezer section and a refrigerated section of a refrigeration unit. The air damper unit includes a drive motor along one side of the damper wall and a slideable door mounted to the one side of the damper wall. The drive motor laterally moves the slideable door. The air damper includes a heating circuit printed on an opposite side of the damper wall.

Inventors:
LARSON ERIC (US)
BARRENA JUAN (US)
CHATELLE WILLIAM (US)
COX JOHN (US)
Application Number:
PCT/US2022/029850
Publication Date:
November 24, 2022
Filing Date:
May 18, 2022
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
ILLINOIS TOOL WORKS (US)
International Classes:
F25D17/04
Domestic Patent References:
WO2014087312A12014-06-12
WO1990003420A11990-04-05
WO2012026470A12012-03-01
Foreign References:
US5490395A1996-02-13
US20080307807A12008-12-18
US20070169504A12007-07-26
DE102017007020A12018-05-09
US4732010A1988-03-22
Attorney, Agent or Firm:
ERICKSON, Kevin, D. (US)
Download PDF:
Claims:
What is claimed is:

1. An air damper unit, comprising: a damper wall mounted between a freezer section and a refrigerated section of a refrigeration unit; a drive motor along one side of the damper wall; a slideable door mounted to the one side of the damper wall, wherein the drive motor is configured to laterally move the slideable door; and a heating circuit printed on an opposite side of the damper wall.

2. The air damper unit according to Claim 1 wherein the damper wall comprises a plurality of wall apertures along a length of the damper wall.

3. The air damper unit according to Claim 1 or 2 wherein the slideable door comprises a plurality of door apertures along a length of the slideable door.

4. The air damper unit according to Claim 3 wherein the plurality of door apertures are of like size and shape as the plurality of wall apertures.

5. The air damper unit according to Claim 2 wherein the damper wall further comprises a plurality of longitudinal bars, wherein the longitudinal bars extend across the length of the damper wall, wherein each longitudinal bar of the plurality of longitudinal bars is adjacent to a wall aperture of the plurality of wall apertures, and wherein the heating circuit extends longitudinally across each longitudinal bar of the plurality of longitudinal bars.

6. The air damper unit according to one of the preceding claims wherein the drive motor is configured to move the slideable door between an open position and a closed position.

7. The air damper unit according to Claim 6 wherein the plurality of wall apertures are in line with the plurality of door apertures in the open position, wherein the open position further comprises a plurality of through apertures.

8. The air damper unit according to Claim 6 wherein the plurality of wall apertures are off-set from the plurality of door apertures in the closed position.

9. The air damper unit according to one of the preceding claims wherein the heating circuit comprises a conductive polymer thick film screen printed onto a plastic sheet.

10. The air damper unit according to Claim 9 wherein the plastic sheet is thermoformed onto the opposite side of the damper wall.

11. The air damper unit according to Claim 9 wherein the plastic sheet comprises polycarbonate.

12. The air damper unit according to one of the preceding claims wherein the heating circuit at least partially surrounds the location of the drive motor.

13. The air damper unit according to one of the preceding claims wherein the heating circuit extends around a footprint of the drive motor.

14. The air damper unit according to Claim 2 wherein the heating circuit surrounds the plurality of wall apertures.

15. The air damper unit according to Claim 9 wherein the plastic sheet further comprises a control circuit.

16. An air damper for controlling cooling air flow in a refrigerator, the air damper comprising: a stationary damper wall mounted to a refrigerator, wherein a portion of the stationary damper wall comprises a plurality of elongated openings; a synchronous drive motor on one side of the damper wall, wherein the synchronous drive motor comprises an oscillator circuit; a slideable door mounted to the one side of the damper wall, wherein the slideable door comprises a plurality of door openings of like size as shape as the plurality of elongated openings, and wherein the synchronous drive motor is configured to laterally move the slideable door between an open position and a closed position; and a heating circuit thermoformed to an opposite side of the stationary damper wall as the one side.

17. The air damper for controlling cooling air flow in a refrigerator according to Claim 16 wherein the heating circuit provides a degree of heat to the damper wall.

18. The air damper for controlling cooling air flow in a refrigerator according to Claim 16 or 17 wherein the stationary damper wall further comprises a plurality of longitudinal bars, wherein each bar of the plurality of longitudinal bars is adjacent to at least one elongated opening of the plurality of elongated openings.

19. The air damper for controlling cooling air flow in a refrigerator according to Claim 18 wherein the heating circuit surrounds each elongated opening of the plurality of elongated openings at the plurality of longitudinal bars.

20. The air damper for controlling cooling air flow in a refrigerator according to Claim 16 or 19 wherein the opposite side of the stationary damper wall further comprises a control circuit with electronic components.

Description:
AIR DAMPER WITH INTEGRATED HEATER BACKGROUND OF THE INVENTION Field of the Invention

This invention relates generally to an air damper and, more particularly, to an air damper with an integrated heater for a refrigerator.

Description of Related Art

Air dampers are often included in refrigeration systems to provide cool air between a refrigerated section and a freezer section of such systems. Air dampers allow cold air from the freezer section to enter the fresh food compartment of the refrigerated section for cooling purposes. Air dampers commonly include an evaporator fan that moves the air from the freezer section to the refrigerated section.

Two common air damper systems include slide action air dampers and flapper action air dampers. A slide action air damper uses a sliding plate that slides back and forth to let air through, or prevent air from passing through, the air damper. A flapper action damper uses a flap or louver that opens and closes to control air flow.

A 120 VAC synchronous motor with a gear box is customarily used to move the sliding plate or flap(s) of an air damper. The gear box is necessary to increase torque of the system and to break any ice bond that forms between the parts of the air damper. Otherwise, ice bonds that form can prevent the air damper from opening and closing.

Known air dampers have a failure mode that occurs when an ice bond is strong enough to where the torque from the gear box is not sufficient to break the ice bond, thereby preventing the air damper from moving between the closed and open positions. If stuck in the closed position, the failed air damper leads to a warm refrigerated section since the cold air from the freezer section is not allowed to enter from the freezer. If stuck in the open position, the failed air damper leads to frozen items in the fresh food section since too much cold air is entering the refrigeration section from the freezer.

In some cases, an ice bond can become strong enough to cause the motor of the damper to break, and in turn breaking the various components of the damper assembly. Therefore, there is a desire for improved air dampers in refrigeration systems that maintain efficient migration of cool air from a freezer compartment to a refrigeration compartment, while also prolonging the life of the air damper and its associated components. SUMMARY OF THE INVENTION

The invention generally relates to an air damper with an integrated heater for a refrigerator.

The general object of the invention can be attained, at least in part, through an air damper unit. The air damper unit includes a damper wall mounted between a freezer section and a refrigerated section of a refrigeration unit. The air damper unit also includes a drive motor along one side of the damper wall and a slideable door mounted to the one side of the damper wall. The drive motor is able to laterally move the slideable door. A heating circuit is also included on the air damper. The heating circuit is printed on an opposite side of the damper wall.

The damper wall includes a plurality of wall apertures along a length of the damper wall. The slideable door includes a plurality of door apertures along a length of the slideable door. The plurality of door apertures are of like size and shape as the plurality of wall apertures.

The damper wall also includes a plurality of longitudinal bars. The longitudinal bars extend across the length of the damper wall. Each longitudinal bar of the plurality of longitudinal bars is adjacent to a wall aperture of the plurality of wall apertures. The heating circuit extends longitudinally across each longitudinal bar of the plurality of longitudinal bars.

The drive motor moves the slideable door between an open position and a closed position. The plurality of wall apertures are in line with the plurality of door apertures in the open position. The open position includes a plurality of through apertures. The plurality of wall apertures are off-set from the plurality of door apertures in the closed position.

The heating circuit includes a conductive polymer thick film screen printed onto a plastic sheet. The plastic sheet is thermoformed onto the opposite side of the damper wall. The plastic sheet includes polycarbonate. The heating circuit can at least partially surround the location of the drive motor. The heating circuit can also extend around a footprint of the drive motor. The heating circuit surrounds the plurality of wall apertures. The plastic sheet also includes a control circuit.

The general object of the invention can also be attained through an air damper for controlling cooling air flow in a refrigerator. The air damper includes a stationary damper wall mounted to a refrigerator. A portion of the stationary damper wall includes a plurality of elongated openings. The air damper also includes a synchronous drive motor on one side of the damper wall. The synchronous drive motor includes an oscillator circuit. The air damper includes a slideable door mounted to the one side of the damper wall. The slideable door includes a plurality of door openings of like size as shape as the plurality of elongated openings. The synchronous drive motor laterally moves the slideable door between an open position and a closed position.

The air damper has a heating circuit thermoformed to an opposite side of the stationary damper wall as the one side. The heating circuit provides a degree of heat to the damper wall. The stationary damper wall includes a plurality of longitudinal bars. Each bar of the plurality of longitudinal bars is adjacent to at least one elongated opening of the plurality of elongated openings. The heating circuit surrounds each elongated opening of the plurality of elongated openings at the plurality of longitudinal bars. The opposite side of the stationary damper wall includes a control circuit with electronic components.

Other objects and advantages will be apparent to those skilled in the art from the following detailed description taken in conjunction with the appended claims and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an air damper according to the prior art;

FIG. 2 shows an air damper according to the prior art;

FIG. 3 shows an air damper in a closed position according to one embodiment of the invention;

FIG. 4 shows an air damper in an open position according to the embodiment shown in FIG. 3;

FIG. 5 shows an alternative view of an air damper in an open position according to the embodiment shown in FIG. 3;

FIG. 6 shows a cross-sectional view of an air damper according to the embodiment shown in FIG. 3;

FIG. 7 shows an electrical schematic for an air damper according to one embodiment of the invention;

FIG. 8A shows a heating circuit for an air damper according to one embodiment of the invention;

FIG. 8B shows an alternative view of a heating circuit for an air damper according to the embodiment shown in FIG. 8A; and

FIG. 9 shows a thermal diagram of a heating circuit for an air damper according to the embodiment shown in FIG. 8A. DETAILED DESCRIPTION OF THE INVENTION

The present invention integrates a heater into an air damper for a refrigerator. The heater prevents the air damper from freezing in place, thereby preventing the air damper from failing. Previous air dampers would freeze and fail, causing excessive cold air to flow into a refrigerated section; or preventing sufficient cold air to flow into the refrigerated section because air cannot flow at proper intervals from a freezer section to the refrigerated section of the refrigerator.

FIG. 1 shows an example of such an air damper. An air damper 10 is a slide action air damper according to the prior art. A slide action air damper includes a damper piece with slits. The damper piece slides back and forth so the slits in effect open and close an air pathway from the air damper in a freezer, to a refrigerated section in a refrigerator. FIG. 2 shows another example of an air damper according to the prior art. In FIG. 2, a flapper action air damper 12 includes a hinged-flap that swings between an open and closed position to provide cool air flow. Both air dampers 10 and 12 move via common actuation with a synchronous motor and a gear box. When ice bonds form on the components of these air dampers due to the cold of the freezer where the air damper is located, the ice bonds prevent the actuation between the open and closed positions. This also causes damage and/or breakage to components of the air dampers due to the ice bonds. These failure modes that occur with the air dampers shown in FIGS. 1 and 2 are remedied with an air damper according to the present invention.

FIG. 3 shows an air damper unit 100 according to the present invention. The air damper unit 100 is placed in a refrigeration unit (not shown). The air damper unit 100 may be mounted between a freezer section and a refrigerated section of the refrigeration unit. As shown, the air damper unit 100 is in a closed position 102. When in the closed position 102, the air damper unit 100 prevents cool air from the freezer section from entering the refrigerated (or fresh food) section. When additional cool air is needed in the refrigerated section, the air damper unit 100 can be moved to an open position, shown in FIG. 4.

The air damper unit 100 includes a damper wall 106. The damper wall 106 is preferably stationary once the unit is mounted in or on a refrigerator. One side 110 of the damper wall 106 includes a drive motor 108. A slideable door 114 is also mounted on the one side 110. The drive motor 108 includes a motor cap 120 and at least one motor stop 122. The motor cap 120 is a cover that at least partially encloses the drive motor 108. The motor cap 120 also interacts with the motor stop(s) 122 to aid in directing the drive direction of the motor 108. The drive motor 108 is a bi-directional motor and moves the slideable door 114 along the damper wall 106. The drive motor 108 engages with the slideable door 114 via an engagement point 118 to move the door 114. The drive motor 108 is preferably a synchronous motor that can be used without the addition of a gearbox. A gearbox is not necessary as the air damper unit 100 includes a heating component (explained in further detail below) that melts any ice layer formed between the moving parts of the air damper unit 100. This allows the drive motor of the claimed invention to be less complex than with previous air dampers. The drive motor is preferably a 12VAC synchronous motor driven by 12VDC power and a simple oscillator circuit.

The slideable door 114 is held to the one side 110 of the damper wall 106 with a series of wall brackets 116. The wall brackets 116 allow the slideable door 114 to slide bi directionally with the drive motor 108. The damper wall 106 preferably includes four wall brackets 116 for the door 114, although other quantities may be used as is suitable to hold and slide the door. For example, the brackets 116 may include bypass brackets and/or a sliding track. As the drive motor rotates either clockwise or counterclockwise, the door 114 is moved either left or right from the engagement point 118. The drive motor 108 can have two backstops 122, one to stop the motor when traveling clockwise, and the other to stop the motor when traveling counterclockwise.

As shown, in the closed position 102, the slideable door 114 includes a plurality of door apertures 130. The door apertures 130 are elongated openings spaced along a length 126 across a surface of the slideable door 114. When in the closed position 102, the apertures 130 provide a through-path to the one side 110 of the damper wall 106. The apertures 130 are rectangular and spaced equidistant from each other along the door 114 with longitudinal bars adjacent to each aperture 130, resembling a gate-like appearance throughout the door 114. In other embodiments of the invention, the apertures may be unevenly spaced across the door. The apertures may be of a variety of shapes including circular, oval, square, triangular or irregular shapes. In one embodiment a single door may include several different shapes of apertures. Embodiments of the invention may also include a variety of quantities of apertures across the door.

When the drive motor 108 engages the slideable door 114 from the closed position 102, the slideable door 114 moves to an open position 104, shown in FIG. 4. As shown in FIG. 4, the slideable door 114 moves along a length 124 of the damper wall 106, which reveals a plurality of wall apertures 128. The wall apertures 128 are elongated openings spaced along the length 124 of the damper wall 106. The wall apertures 128 are of like size and shape (rectangular in this embodiment) as the door apertures 130. This results in a plurality of through apertures 138 in the open position 104, so that air can pass through the damper 100. As with the door apertures 130, the wall apertures 128 may be a variety of shapes, sizes and quantities in various embodiments of the invention.

FIG. 5 shows the air damper unit 100 in the open position 104 from an opposite side 112 of the damper wall 106. The through openings 138 are each adjacent to at least one longitudinal bar 136. The longitudinal bars 136 are spaced across the length 124 of the damper wall 106 in between the through openings 138. Some embodiments of the invention may not include the longitudinal bars, but rather include fill-in space(s) in any number of shapes and sizes between the through apertures. The damper wall 106 also has a motor opening 152. The motor opening 152 allows access to the drive motor 108 and can also act as a mounting mechanism to attach the drive motor 108 to the damper wall 106.

The opposite side 112 of the damper wall 106 also includes a heating circuit 134. The heating circuit 134 extends across the damper wall 106. The heating circuit 134 at least partially surrounds the location of the drive motor 106. The heating circuit 134 also surrounds the plurality of wall apertures 128. Specifically, the heating circuit 134 extends down the plurality of longitudinal bars 136 so that the heating circuit 134 surrounds each aperture of the wall apertures 128. A layout of the heating circuit 134 may be modified and adapted to air damper units of a variety of shapes and sizes.

The heating circuit 134 provides heat to the components of the air damper unit 100 so that ice bonds do not form across the components. This allows the air damper unit to freely move between the open and closed positions without failure of the system due to ice bonds. The heating circuit 134 is preferably on a conductive polymer thick film screen 140 as shown in FIG. 6. The heating circuit 134 and film screen 140 are printed onto a plastic sheet 142. The plastic sheet 142 can be thermoformed onto the opposite side 112 of the damper wall 106. By thermoforming the plastic sheet onto the damper wall, the heating circuit can more adequately provide heat to the various components of the air damper unit that with a flat sheet attached to the damper wall. In one embodiment of the invention the plastic sheet is made of polycarbonate. The polycarbonate has a thickness of approximately 10-30mm, preferably 20mm. When the air damper unit 100 is in the open position 104, the heating circuit 134 is able to deliver heat to both the damper wall 106 and the door 114. When in the open position, the longitudinal bars 136, with part of the heating circuit 134, are superimposed onto bars 154 of the door 114 so that heat from the heating circuit 134 can reach the components of the slideable door 114, as well as the components of the damper wall 106. In a similar fashion, since the heating circuit 134 at least partially surrounds a footprint of the drive motor 108, heat is also provided to the components of the drive motor, preventing ice bonds form accumulating on the drive motor. This allows the drive motor to continue running smoothly to operate the air damper unit.

The electrical components of the air damper unit, such as the heating circuit and components for the drive motor, are controlled with a control circuit 146 - shown generally in FIG. 7. The control circuit 146 generally includes electronic components 150 for monitoring and controlling various aspects of the air damper unit. A variety of control circuits can be printed onto the polymer sheet along with the heating circuit. One such control circuit includes an oscillator circuit 148. The oscillator circuit 148 drives the damper motor along with 12VDC power. In one embodiment of the invention, the damper motor is a 12VAC synchronous motor driven by the oscillator circuit and the 12VDC power.

The electronic components 150 can also be mounted to the polymer sheet using conductive epoxy or other suitable means. The electronic components 150 can include components for numerous control circuits such as the oscillator circuit, among many other components. Other circuits and associated components that may be mounted to control and/or monitor parts of the air damper unit may include a microcontroller circuit, a damper position sensor circuit, a bi-directional motor circuit, a power supply circuit, a data interface circuit, a de-icing heater drive circuit, a temperature sensor circuit, and a jam detecting circuit, among others.

All of the circuits and their associated components can be printed onto the polymer sheet before the sheet is placed on the damper wall. Preferably, all the circuits printed onto the polymer sheet are then therm oformed with the plastic sheet onto the damper wall. FIG. 8 A shows the plastic sheet 142 with the heating circuit 134 thermoformed onto the sheet 142. This sheet 142 can then be attached to the damper wall. As shown, the heating circuit 134 surrounds a footprint 144 for the drive motor, as well as a footprint for the plurality of wall apertures. FIG. 8B shows the plastic sheet 142 with the heating circuit 134 from an alternating, opposite view, from that shown in FIG. 8A. Having the heating circuit 134 thermoformed to surround various components of the air damper unit results in adequate heat to reach all the moving components so that the air damper unit functions properly without suffering damage or reduced function due to ice build-up.

The present invention is described in further detail in connection with the following examples which illustrate or simulate various aspects involved in the practice of the invention. It is to be understood that all changes that come within the spirit of the invention are desired to be protected and thus the invention is not to be construed as limited by these examples.

A thermal diagram of the heat that can be provided from the heating circuit 134 is shown as an example in FIG. 9. As the heating circuit was activated in this example, temperatures were measured at various points across the heating circuit. These points include Bxl, Bx2, Bx3, Bx4, Bx5, Bx6, Bx7, Bx8, and Bx9. These points included positions around the heating circuit that wove around the plurality of wall apertures. The temperatures were taken over an interval of 91 seconds. A minimum, maximum, and average temperature was calculated at each measurement point, as shown in Table 1 below.

Table 1: Thermal Measurements

The average temperature of all positions Bxl-Bx9 ranged from 41 8°C to 69.8°C. The temperature surrounding the circuit remained at approximately 20-30°C. The invention illustratively disclosed herein suitably may be practiced in the absence of any element, part, step, component, or ingredient which is not specifically disclosed herein.

While in the foregoing detailed description this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for purposes of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that certain of the details described herein can be varied considerably without departing from the basic principles of the invention.