Patent Application
20090019870
1. Field of the Invention
The present invention pertains to the art of refrigerators and, more particularly, to a variable position damper that can be selectively controlled to deliver cooling air into a freezer compartment and/or a fresh food compartment of a refrigerator.
2. Description of the Related Art
There are many systems for delivering cooling air into refrigerator compartments to maintain selected temperatures. In some cases, the refrigerator is provided with two cooling systems, one system delivering cooling air into the freezer compartment and another, separate system, delivering cooling air into the fresh food compartment. While effective, the manufacturing costs associated such refrigerators are high. Moreover, operating multiple cooling systems reduces an overall efficiency of the appliance.
In other cases, cooling air is first delivered into the freezer compartment to establish a freezer compartment temperature. With this arrangement, cool air is directed from the freezer compartment into the fresh food compartment to establish and/or maintain a desired fresh food compartment temperature. Typically, the cool air is guided through a passage that interconnects the freezer and fresh food compartments. A damper is typically arranged within the passage to selectively allow cooling air to pass into the fresh food compartment when necessary, and close off the passage absent a need for cooling air. Efficiency gains were realized with the use of variable position dampers that control how much cooling air is passed into the fresh food compartment. Additional efficiencies were realized with the use of variable capacity compressors and variable speed fans. As a demand for cooling is sensed, instead of operating at maximum output, the compressor and fans are driven at a speed sufficient to satisfy a particular cooling demand.
Unfortunately, the energy savings realized in known systems that employ dampers is limited. Usually, most of the cooling demand is required in the freezer compartment. In situations where the fresh food compartment requires a small adjustment, the cooling system needs to overdrive the freezer compartment in order to have sufficient cooling air to siphon off to the fresh food compartment. In some cases, a demand for cooling in the fresh food compartment is not met until the freezer compartment also requires cooling. In order to address this problem, some manufacturers position the damper between the cooling system and both the freezer and fresh food compartments. In this configuration, the damper is positioned to deliver cooling air into one or the other compartment depending on a particular cooling demand.
In one such arrangement, the damper is positioned at an opening in a side wall of an air plenum. The damper is shifted to allow cooling air into one, the other or both of the freezer and fresh food compartments. While effective, the particular geometry of the damper leads to inefficient air transfer. Back pressure, created by turbulences in the air flow, impedes delivery of cooling air into one or the other compartment. When the damper is positioned to allow air to pass into both compartments, the back pressure results in the volume of air flowing into each compartment to be unregulated.
Based on the above, despite the existence of refrigerator air delivery systems in the prior art, there still exists a need for a refrigerator air delivery system that employs a variable position damper to deliver air to multiple refrigerated compartments either individually or simultaneously. Moreover, there exists a need for a variable position damper that includes an air scoop to reduce air turbulence and efficiently deliver cooling air into freezer and/or fresh food compartments.
The present invention is directed to a refrigerator including a cabinet having top, bottom, rear and opposing side walls that collectively define a freezer compartment and a fresh food compartment and, more particularly, to a cooling system that develops and delivers a cooling air flow into the freezer and fresh food compartments. The cooling air flow is guided through an air plenum that interconnects the cooling system with the freezer compartment and the fresh food compartment. In accordance with the invention, a variable position air damper is slidably mounted within the air plenum. The variable position air damper includes a first, substantially straight portion which leads to an arcuate portion that forms an air scoop. The air damper is selectively positioned to deliver the cooling air flow into the fresh food and/or freezer compartments, with the air scoop minimizing air flow turbulences, thereby creating efficiencies in the air flow.
In further accordance with the invention, the refrigerator includes a drive motor that selectively positions the damper to deliver the cooling air flow into the freezer and/or fresh food compartments. Operation of the drive motor is established by a control unit. The control unit is linked to temperature sensors located in the freezer and fresh food compartments. Upon receipt of a signal from a temperature sensor, the control unit selectively activates the drive motor to establish a position of the air damper to satisfy a sensed cooling need.
In accordance with one embodiment of the invention, the air damper slides between a first position, wherein cooling air is diverted into the freezer compartment, and a second position, wherein cooling air is directed into the fresh food compartment. The air damper can be selectively arranged in an infinite number of intermediate positions to deliver cooling air into both the freezer and fresh food compartments. Preferably, at least a portion of the air damper is formed from a flexible material that facilitates transition between the first and second positions.
In accordance with another embodiment of the present invention, the air damper slides along a longitudinal axis of the air plenum. More specifically, the air damper slides along a guide track positioned within the air plenum. With this arrangement, the air damper can be selectively positioned in a first position, wherein all of the cooling air passes to the freezer compartment, and a second position wherein all of the cooling air passes to the fresh food compartment. As with the first embodiment, the air damper can be placed in an infinite number of intermediate positions to control a volume of cooling air being delivered to each of the freezer and fresh food compartments, with the air scoop advantageously reducing air flow turbulence to increase air flow efficiency.
Additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of preferred embodiments when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views.
With initial reference to
In a manner known in the art, refrigerator 2 includes a control panel 31 which enables a consumer to set desired temperatures for freezer compartment 12 and fresh food compartment 13. Towards that end, control panel 31 includes a plurality of control elements 33 and 34 each being associated with a corresponding display 35 and 36. As illustrated, control panel 31 is operatively connected to a control 40. Control 40, in a manner also known in the art, receives inputs from the plurality of control elements 33 and 34, as well as temperature sensors 42 and 43 located within freezer compartment 12 and fresh food compartment 13 respectively, to establish the need for cooling. More specifically, upon sensing a need for cooling, control 40 activates a cooling system 44 having at least a fan 46 that directs a cooling air flow into freezer compartment 12 and/or fresh food compartment 13 to establish and maintain the selected temperatures. In accordance with the invention, cooling air is directed along rear wall 19 of freezer compartment 13 through a variable position air damper system 50 and into freezer compartment 12 and/or fresh food compartment 13 as will be discussed more fully below.
As best shown in
In accordance with the embodiment shown in
In further accordance with the embodiment shown, damper 68 includes a first or substantially straight portion 97 that leads to a second or arcuate portion 99 including a solid portion 99a and an open portion 99b that is established by a plurality of strips 100-102 which collectively define outlet 69 that opens upward to create a preferential air flow which circulates about freezer compartment 12. In the most preferred form of the invention, damper 68 is formed from a flexible material that allows damper 68 to readily transition between the first and second positions. More specifically, when damper 68 transitions from the first position to the second position, arcuate portion 99 slides along a rear wall 103 of air plenum 59. By forming arcuate portion 99 from a flexible material, this transition is smooth, reliable and repeatable. In addition, arcuate portion 99 includes a concave surface (not separately labeled) that defines an air scoop. The air scoop enhances flow characteristics of the cooling air passing over damper 68. More specifically, the air scoop minimizes turbulence in the cooling air flow such that the airflow is channeled or smoothed, i.e., substantially laminar. By ensuring that the cooling air flow is channeled or smoothed, any back pressure caused by turbulence(s) in the air flow which could inhibit or reduce the air flow passing into freezer compartment 12 is virtually eliminated.
Reference will now be made to
As shown, sliding portion 142 includes a substantially first or straight section 145 that interengages with guide track 141 and a second or arcuate portion 146 that collectively defines, together with static portion 140, a fresh food air plenum 148. In a manner similar to that described above, arcuate section 146 includes a concave surface that defines an air scoop which advantageously enhances flow characteristics of the cooling air flow passing over damper member 138. In accordance with the invention, damper 138 is operated by an automatic, preferably temperature-based control motor (not shown). The motor could take on various forms, such as a solenoid, a wax motor, DC electric motor, or the like. In accordance with another aspect of the invention, damper 138 is driven by a linkage 150 interconnecting door 90 and sliding portion 142. Of course, if so desired, damper 138 could also be constructed so as to be manually operated.
In accordance with the embodiment shown, control 40, upon sensing a demand for cooling in either freezer compartment 12 or fresh food compartment 13, activates cooling system 44 to develop a cooling air flow. Depending upon the compartment(s) requiring cooling, sliding damper 138 is selectively positioned relative to inlet opening 132. If the demand for cooling is solely in freezer compartment 12, sliding damper 138 is arranged in a first position shown in
As indicated above, in addition to tailoring the air flow of cooling air into each compartment, the present invention advantageously employs curved or curvilinear surfaces that channel or smooth the airflow in order to minimize turbulence. By ensuring that the air flow is channeled or smoothed, air flow characteristics are greatly improved, e.g., any back pressure that would result from the creation of turbulences in the air flow is negated. In this manner, the present invention ensures that the desired volume of cooling air is passed into freezer compartment 12 and/or fresh food compartment 13. In addition to the efficiencies created by the present invention, additional components, such as variable speed compressors, variable speed fans and the like, can also be employed to provide further efficiency gains for refrigerator 2.
Although described with reference to preferred embodiments of the invention, it should be readily understood that various changes and/or modifications can be made to the invention without departing from the spirit thereof. For instance, while each variable position damper is shown to include a single outlet, a bifurcated outlet can also be employed to direct air flow into various portions of the fresh food compartment in order to avoid temperature stratification. In addition, open portion 99b could be formed by a plurality of openings or perforations. In general, the invention is only intended to be limited by the scope of the following claims.
