Appliance control system

• US 4,843,833 A
• Filed: 08/24/1987
• Issued: 07/04/1989
• Est. Priority Date: 03/06/1984
• Status: Expired due to Term

• Current Assignee: Whirlpool Corporation
• Original Assignee: TRW Canada Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Polkinghorne, John
• Primary Examiner(s): Tanner, Harry B.
• Application Number:
  US07/089,026
• Time in Patent Office: 680 Days
• Field of Search: 62/180, 62/186, 62/187, 62/208, 62/213, 62/226, 62/227, 62/229, 62/200, 62/156, 62/150, 62/175, 62/126, 62/127, 62/129, 62/130, 62/182, 251/129.09, 251/129.1, 251/129.05
• US Class Current: 62/180
• CPC Class Codes: F25D 17/045 Air flow control arrangements
• CPC Class Codes: F25D 17/065 with compartments at different temperatures
• CPC Class Codes: F25D 21/002 Defroster control
• CPC Class Codes: F25D 2400/04 Refrigerators with a horizontal mullion
• CPC Class Codes: F25D 2700/02 Sensors detecting door opening
• CPC Class Codes: F25D 29/00 Arrangement or mounting of control or safety devices
• CPC Class Codes: G05D 23/1917 using digital means
• CPC Class Codes: G05D 23/24 the sensing element having a resistance varying with temperature, e.g. a thermistor

Abstract

This invention relates to a system for the control of electrical apparatus with particular reference to control by electric sensors, and with special reference to a control system for domestic appliances, such as refrigerators. The system may be adapted to control of appliances such as dishwashers, dryers, washers, stoves, etc. The preferred embodiment is microcomputer based. Thus, the system enables lower energy consumption, more accurate temperature maintenance and more effective servicing and monitoring of the mechanical condition of the apparatus to which it is applied.

Claims

1. A refrigerator-freezer combination comprising:

a refrigerator compartment for holding food stuffs that are to be maintained at a chilled, above freezing temperature;

a freezer compartment for retaining food stuffs that are to be held at a below freezing temperature;

a cooling coil disposed in the freezer compartment for cooling air below freezing when receiving a coolant fluid from a compressor;

a fan means for circulating air over the cooling coil;

a duct work system operatively connecting with the refrigerator compartment, the freezer compartment, the fan, and the cooling coil such that the fan draws air from both the refrigerator and freezer compartments and circulates it over the cooling coil, the duct work system further channelling cooled air from the cooling coil to the freezer compartment and from the frozen compartment to the refrigerator compartment;

a freezer temperature sensing means for sensing a temperature sensed in the freezer compartment;

a refrigerator compartment temperature sensing means for sensing temperature in the refrigerator compartment;

a control means responsive to the freezer compartment temperature sensing means sensing a temperature above a freezer compartment set point for causing (i) the cooling coil and compressor to start cooling air to a temperature below the freezer compartment set point and (ii) the fan means to start circulating air from the refrigerator and freezer compartments across the cooling coil, the control means continuing to cause the fan means to circulate air over the cooling coil and the compressor to continue supplying coolant fluid to the cooling coil to cool the circulating air until both the freezer compartment temperature sensing means senses a temperature at or below the freezer compartment set point and the refrigerator compartment sensing means senses a temperature at or below a refrigerator compartment set point, whereby the freezer compartment continues to be cooled below the freezer compartment set point until the refrigerator compartment reaches the refrigerator compartment set point.

2. The refrigerator-freezer combination as set forth in claim 1 further including a damper means disposed in the duct work system for selectively adjusting a ratio of the air from the cooling means circulated by the fan means to the refrigerator and freezer compartments.

3. The refrigerator-freezer combination as set forth in claim 2 wherein the damper means includes:

a housing interconnected with the duct work system, the housing defining an opening in fluid communication with one of the freezer and refrigerator compartments;

a damper member mounted for movement between an open position in which the opening is substantially unobstructed and a closed position in which the opening is obstructed; and

,

an electro-magnetic means for selectively moving said damper member between the open and closed positions.

4. The refrigerator-freezer combination as set forth in claim 3 wherein the electro-magnetic means includes a first coil for moving the damper toward the open position and a second coil for moving the damper toward the closed position.

5. The refrigerator freezer combination as set forth in claim 4 further including:

a charge pulse supply means for selectively applying a first charge pulse to the first coil and a second charge pulse to the second coil, the relative sizes of the first and second pulses controlling relative movement of the damper.

6. The refrigerator-freezer combination as set forth in claim 1 further including a sampling means for cyclically sampling the refrigerator and freezer compartment temperature sensing means, the sampling means being operatively connected with the control means to convey the sensed temperatures thereto.

7. The refrigerator-freezer combination as set forth in claim 6 further including:

a defrosting heater disposed adjacent the cooling means for selectively defrosting the cooling means;

a rate of fall determining means operatively connected with the sampling means for measuring a rate of fall of temperature sensed by at least one of the refrigerator and freezer compartment temperature sensing means; and

,

a defrost heater actuation means for actuating the defrost heater in response to the measured temperature fall rate being slower than a preselected rate.

8. The refrigerator-freezer combination as set forth in claim 7 further including a disabling means for disabling the cooling means and the fan means while the defrost heater is actuated.

9. The refrigerator-freezer combination as set forth in claim 7 further including a cooling means temperature sensing means for sensing the temperature of the cooling means and a defrost heater deactuating means for selectively deactuating the defrost heater in accordance with the sensed cooling temperature.

10. The refrigerator-freezer combination as set forth in claim 1 further including:

a door for closing at least one of the refrigerator and freezer compartments;

a mullion on the one compartment surrounding the door, which mullion is subject to environmental moisture condensation thereon;

a mullion heating means disposed adjacent the mullion;

a mullion temperature sensing means mounted on the mullion for sensing the temperature thereadjacent; and

,

a mullion heater actuating means for selectively actuating the mullion heater to hold the mullion at a temperature above a preselected minimum temperature.

11. The refrigerator-freezer combination as set forth in claim 1 further including;

a door for closing at least one of the refrigerator and freezer compartments;

a ferromagnetic material mounted in one of the door and the compartment;

a magnetic gasket mounted to the other of the door and the compartment for sealing the door and the compartment by magnetic attraction therebetween;

a Hall-effect switch mounted on the said other of the door and compartment, the Hall-effect switch being switched between first and second states by proximity of the magnetic gasket such that the Hall-effect switch is in a first state when the door is closed and a second state when the door is opened.

12. The refrigerator-freezer combination as set forth in claim 1 further including:

a cooling means temperature sensing means for sensing temperature of the cooling means;

a comparing means for comparing the sensed temperature of the cooling means during operation of the cooling means with the sensed temperature of the cooling means prior to operation to determine a temperature differential therebetween; and

,

a malfunction indicating means operatively connected with the comparing means for indicating a system malfunction in response to the temperature differential failing to exceed a selected minimum temperature differential.

13. The apparatus as set forth in claim 1 further including a delay means operatively connected between the control means and the fan means for delaying operation of the fan means such that operation of the fan means is delayed for a short duration after the cooling means is enabled.

16. The refrigerator-freezer combination as set forth in claim 2 further including a logic means having:

a plurality of input ports for receiving input signals representative of operating parameters;

a processing means for processing the input signals and determining a damper position therefrom in accordance with the operating parameters; and

,

an output port for supplying a control signal to the electromotive means to move the damper to said position.

17. The refrigerator-freezer combination as set forth in claim 2 wherein the damper means includes:

a damper door disposed adjacent a wall which separates the refrigerator and freezer compartments and slideable between a closed position in which air flow is blocked and an open position in which air flow is permitted, the damper means being oriented such that the damper door slides in a substantially horizontal direction, whereby gravity does not bias said damper door toward either the open or closed position; and

electromagnetic means operatively connected with the damper door for selectively sliding said damper door between the open and closed positions, the electromagnetic means including a first coil responsive to a first electrical signal for sliding the damper door to the closed position and a second coil responsive to a second electrical signal for sliding the damper door to the open position;

whereby the damper door is selectively opened and closed by transitory application of the first or second electrical signals and remains in the position without continuous expenditure of electrical energy.

14. A refrigerator-freezer combination comprising:

a refrigerator compartment for holding food stuffs that are to be maintained at a chilled, above freezing temperature;

a freezer compartment for retaining food stuffs that are to be held at a below freezing temperature;

a cooling means for cooling air below freezing;

a fan means for circulating air over the cooling means;

a duct work system operatively connected with the refrigerator compartment, the freezer compartment, the fan, and the cooling means such that the fan draws air from both the refrigerator and freezer compartments and circulates it over the cooling means and into at least the freezer compartment;

a housing interconnected with the duct work system, the housing defining an opening in fluid communication with the refrigerator compartment;

a damper member mounted for movement between an open position in which the opening is at least partially unobstructed and a closed position in which the opening is obstructed;

an electro-magnetic means for selectively moving said damper member between the open and closed positions;

an actuating means for actuating the electro-magnetic means, the actuating means including;

a charger storage capacitor;

a charging means for charging the capacitor in a first duration;

a switching means for switching the electro-magnetic means across the capacitor and for pulsing current therethrough to move the damper member, pulsing current through the electro-magnetic means discharges the capacitor in a second duration which second duration is shorter than the first duration; and

,

an inhibiting means for inhibiting connection of the capacitor across the electro-magnetic means until the capacitor has been recharged by a recharging means, whereby the damper door is inhibited from being moved for a difference between the first and second durations after each actuation;

a freezer temperature sensing means for sensing a temperature sensed in the freezer compartment;

a refrigeration compartment temperature sensing means for sensing temperature in the refrigerator compartment;

a control means responsive to the freezer compartment temperature sensing means sensing a temperature above a freezer compartment set point for causing (i) the cooling means to start cooling air to a temperature below the freezer compartment set point and (ii) the fan means to start circulating air from the refrigerator and freezer compartments across the cooling means, the control means continuing to cause the fan means to circulate air over the cooling means to cool the circulating air until both the freezer compartment temperature sensing means senses a temperature at or below the freezer compartment set point and the refrigerator compartment sensing means senses a temperature at or below a refrigerator compartment set point.

15. A refrigerator-freezer combination comprising:

a refrigerator compartment for holding food stuffs that are to be maintained at a chilled, above freezing temperature;

a freezer compartment for retaining food stuffs that are to be held at a below freezing temperature;

a cooling means for cooling air below freezing;

a fan means for circulating air over the cooling means;

a duct work system operatively connected with the refrigerator compartment, the freezer compartment, the fan, and the cooling means such that the fan draws air from both the refrigerator and freezer compartments and circulates it over the cooling means to at least the freezer compartment;

a freezer temperature sensing means for sensing a temperature sensed in the freezer compartment;

a refrigerator compartment sensing means for sensing temperature in the refrigerator compartment;

a control means responsive to the freezer compartment temperature sensing means sensing a temperature above a freezer compartment set point for causing (i) the cooling means to start cooling air to a temperature below the freezer compartment set point and (ii) the fan means to start circulating air from the refrigerator and freezer compartments across the cooling means, the control means continuing to cause the cooling means to cool air and the fan means to circulate air until both the freezer compartment temperature sensing means senses a temperature at or below the freezer compartment set point and the refrigerator compartment sensing means senses a temperature at or below a refrigerator compartment set point;

a damper means connected between the duct work system and the refrigerator compartment for selectively passing cooled air into the refrigerator compartment;

a damper control means responsive to the refrigerator compartment temperature sensing means sensing a temperature above the refrigerator compartment set point for actuating the fan means to circulate air through the duct work system into the freezer compartment and for moving the damper to direct air from the duct work system into the refrigerator compartment, whereby cold air is moved from the freezer compartment to the refrigerator compartment until the freezer compartment temperature sensing means senses a temperature above the freezer compartment set point which causes the control means to start the cooling means cooling and wherein the fan means continues to circulate air from the freezer and refrigerator compartments over the cooling means until both the freezer and refrigerator compartments are below their respective set points.

18. A control system for a refrigeration device having at least first and second cooled compartments which are interconnected by an air door for selectively passing cooled air therebetween, the control system comprising:

a first temperature sensing means disposed in the first compartment for sensing a temperature therein;

an air door control means operatively connected with the first temperature sensing means for operating the air door to allow refrigerated air to pass from the second compartment to the first compartment in response to the sensed temperature in the first compartment rising above a first set point;

a second temperature sensing means disposed in the second compartment for sensing a temperature therein;

a control means for selectively actuating a fan and a cooling means for cooling the second compartment in response to the sensed temperature in the second compartment exceeding a second set point and for deactuating the fan and cooling means in response to the sensed second compartment temperature dropping below the second set point; and

,

an override means operatively connected with the first temperature sensing means for preventing the control means from deactuating the fan and cooling means from cooling the second compartment until the first sensor senses that the sensed temperature in the first compartment has fallen below the first set point, such that the second compartment is cooled below the second set point, whereby efficiency is improved by running the cooling means for fewer longer durations and damage from temperatures in the second compartment above the second set point is minimized.

19. A method of controlling temperatures in at least two refrigeration compartments which are cooled by a common cooling means over which air is passed, the method comprising:

sensing temperature in a first of the compartments;

selectively moving cooled air from a second of the compartments into the first compartment in response to the sensed first temperature compartment rising above a first set point;

sensing a temperature of the second compartment;

actuating the cooling means and circulating air thereacross and into the second compartment in response to the temperature sensed in the second compartment exceeding a second set point;

continuing moving air across the cooling means into the second compartment until both (i) the temperature sensed in the first compartment drops below the first set point and (ii) the temperature sensed in the second compartment drops below the second set point, whereby one of the compartments is cooled below its set point; and

,

after the temperatures of both compartments have dropped below their respective set points, deactuating the cooling means and terminating circulation of the cooled air.

20. The method as set forth in claim 19 further including the step of blocking the moving of cooled air into the first compartment in response to the first compartment dropping below the first set point such that cooled air is moved only to the second compartment.