FIELD OF THE INVENTION

The present invention relates to refrigerators and the like and specifically to a diverter valve for controlling the flow of refrigerated air into different refrigerator compartments.

BACKGROUND OF THE INVENTION

Refrigerators for the storage of food or the like may provide for separate compartments, each maintained at different temperatures. One compartment may be maintained at a temperature substantially below freezing for the storage of frozen food. The other compartment may be maintained at a temperature above freezing for the storage of fresh foods. These different temperatures can be maintained by selectively controlling the flow of air cooled by the refrigerator evaporator (a heat absorber) into one or the other compartment.

Such airflow control is typically provided by an air damper implemented as a mechanical diverter valve of a type having a movable valve plate, such as a flapper door, that is operable by an electric actuator in turn controlled by a refrigerator control circuit. The flapper door is moved between two positions to direct air from the evaporator into one compartment or the other depending on the actuator operation.

The movable flapper door is subject to blockage by the accumulation of ice on the movable valve plate and its engaging valve seats. In addition, the actuator or linkage between the actuator and movable valve plate can become encrusted with ice also interfering with reliable operation of the diverter valve.

SUMMARY OF THE INVENTION

The present invention provides a diverter valve using a fluidic circuit to stably switch airflow from a refrigerator evaporator to one of two compartments without the need for a movable flapper door. The fluidic circuit provides two outlet channels and directs airflow between the channels by a short air jet from an associated electric fan which causes the airflow to “attach” to a different outflow channel. The fluidic circuit eliminates the need for a movable valve plate and its associated sealing tolerances and thus problems of blockage in the movement of the valve plate caused by accumulated ice.

In one embodiment, the invention provides a refrigerator damper system for use in a refrigerator of a type providing first and second compartments receiving refrigerated airflow from a refrigeration circuit including a heat absorbing portion such as an evaporator. The refrigerator damper system includes a diverter housing providing an inlet communicating to a first and second outlet, the latter adapted to communicate with the first and second compartments respectively. A first electrically controllable fan transports air cooled by the heat absorbing portion to the inlet of the diverter housing. The diverter housing provides a fluidic valve having a first main channel leading from the inlet and separating at a bifurcation to first and second channels communicating, respectively, with each of first and second outlets and further having at least one control port positioned at the bifurcation, the control port adapted to conduct air therethrough to steer air from the main channel between the first and second channels. A second electrically controllable fan may transport air through the control port.

It is thus a feature of at least one embodiment of the invention to eliminate the need for movable damper elements that must seal against air leakage and thus that are susceptible to freezing in place with the accumulation of frost or ice.

The bifurcation is adapted to produce an attachment of airflow to a single given wall of either of the first and second channels when air is flowing through the given first and second channels to provide a bi-stable switching of air between the first and second channels without operation of the second electrically controllable fan to move air through the control port.

It is thus a feature of at least one embodiment of the invention to provide a damper system that does not require electrical power to be expended by the second fan except during the switching of airflow, thus conserving energy.

The second electrically controllable fan maybe bidirectional and operates in a first direction to move air from the first to the second channel and in a second direction to move air from the second to the first channel.

It is thus a feature of at least one embodiment of the invention to eliminate the need for two separate control fans to provide control jets for the fluidic valve.

The refrigerator damper system may further include an air reducer communicating between the first electrically controllable fan and the bifurcation to provide an increasing air velocity.

It is thus a feature of at least one embodiment of the invention to provide sufficient air velocity to promote the Coand{hacek over (a)} effect providing for bi-stability while allowing for slower airflow over the refrigerator heat exchanger for maximum thermal interchange.

The diverter housing may be a thermally insulating material having a thermal conductivity of less than 0.1 W/(m/k) such as a polymer material. In one embodiment the material may be an expanded polystyrene foam.

It is thus a feature of at least one embodiment of the invention to provide a diverter that may be constructed of insulating materials forming part of the insulating walls of the compartments.

The main channel and the first and second channels may be coplanar and have an extent perpendicular to the plane of less than two inches. The first and second outlets may open to allow airflow perpendicular to the plane.

It is thus a feature of at least one embodiment of the invention to provide a diverter valve that can fit between the first and second compartment within the space normally allocated to insulation.

The refrigerator damper system may further include an airflow sensor in at least one of the first and second channels.

It is thus a feature of at least one embodiment of the invention to permit active sensing of airflow to ensure upper switching and continuity of switching (for example, when the door the refrigerator is opened) and to minimize operation of the second fan.

The second electrically controllable fan may provide a lower airflow than the first electrically controllable fan and/or may provide lower power consumption than the first electrically controllable fan.

It is thus a feature of at least one embodiment of the invention to provide a control of airflow that reduces the need for expensive or high-power actuators.

Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features.

