Automatic freeze protection for dishwashers

Abstract

A system for protecting a dishwasher from freezing using components within a dishwasher. The system comprising: a control circuit, a heating element, a water pump, drain hose, hot water supply, water valve, door sensor to determine whether dishwasher door is closed and a temperature sensor.

Claims

1. A system for protecting a dishwasher from freezing comprising: a control unit; a heating element; a water pump; drain hose; hot water supply; water valve; door sensor to determine whether dishwasher door is closed; temperature sensor; said sensor activates a freeze protection function of said control circuit once ambient temperature falls to be above freezing; said control circuit confirms said door is closed by said door sensor, and admits hot water from said hot water supply to said dishwasher for a period of time sufficient for heated water to travel from home's water heater to said dishwasher, so local environment of said dishwasher is heated to a certain temperature above freezing; said heating element remains in heating mode until said temperature sensing component returns an ambient temperature above freezing point.

2. The system of claim 1 wherein said system uses components within a standard Dishwasher to protect said dishwasher from freezing.

3. The system of claim 1 wherein said heating element also dries dishes after they have been cleaned and rinsed.

4. The system of claim 1 wherein said water pump ejects waste water to a home's sewer line.

5. The system of claim 1 wherein said hot water is from a home's domestic plumbing system.

6. The system of claim 1 wherein said temperature sensor is mounted in or on said dishwasher.

7. The system of claim 1 wherein said freezing point is approximately 37 degrees F.

8. The system of claim 1 wherein said system has an activation period of approximately two (2) minutes to be sufficient.

9. The system of claim 1 wherein function of admitting hot water for freeze protection is accomplished by existing water valve/solenoid and controls used to operate an ordinary wash cycle.

10. The system of claim 9 wherein said system heats dishwasher's supply line sufficiently to prevent freezing of this part of said system.

11. The system of claim 1 wherein said hot water provided is ejected into said drain hose via operation of said pump.

12. The system of claim 11 wherein function of ejecting hot water is accomplished by activating said pump via control used to conclude a rinse cycle.

13. The system of claim 12 wherein said hot water heats said pump and drain line sufficiently to prevent freezing of this part of said system.

14. The system of claim 1 wherein said heating element is energized using existing thermostatic controls used for dish drying.

15. The system of claim 1 where at point said temperature sensor returns an ambient temperature above freezing point, automatic freeze protection cycle is concluded.

16. The system of claim 1 wherein said freeze protection protects said dishwasher, for significant periods of time, from damage due to a freeze of standing water in said pump, said drain, and/or said supply line as systems re-cools.

17. The system of claim 1 wherein said system reactivates if threat of freezing recurs as indicated by a fall in ambient temperature below a certain temperature.

18. The system of claim 1 wherein said freeze protection function is incorporated in said dishwasher in a manual mode.

19. The system of claim 1 wherein said freeze protection function is incorporated in said dishwasher in a fully automatic mode.

20. The system of claim 18 wherein said manual mode requires operator to engage said freeze protection function if freezing temperatures are expected.

21. The system of claim 19 wherein said automatic mode operates without user interaction to protect said dishwasher automatically.

22. A system for protecting a dishwasher from freezing comprising: a controller located inside said dishwasher; said dishwasher comprising a hot water valve connected to a domestic hot water supply; a heating element located inside said dishwasher; a pump having a waste water discharge line; door position switch; said controller is connected to a temperature sensor, door position switch, pump, hot water valve, and heating element; said temperature sensor activates a freeze protection function of said controller once ambient temperature falls to be just above freezing point; said control circuit confirms door of dishwasher is closed by said door position switch and admits hot water through hot water valve to said dishwasher for a period of time sufficient for heated water to travel from home's water heater to said dishwasher; said hot water valve admits hot water to operate an ordinary wash cycle, heating dishwasher's supply line sufficiently to prevent freezing of this part of said system; hot water provided is ejected into said drain hose via operation of said pump; said pump activated via said control which is also used to conclude a rinse cycle; said hot water heats said pump and drain line sufficiently to prevent freezing of this part of said system; said heating element is energized using existing thermostatic controls used for dish drying; said heating element remains in heating mode until said temperature sensor returns an ambient temperature above freezing point; said controller when activated heats dishwasher to a certain temperature above freezing.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows an internal view of an embodiment of the automatic freeze protection system for a dishwasher of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(2) FIG. 1 shows dishwasher 10 having a controller 12 that is located within the dishwasher 10 but located outside the dishwasher for clarity. The dishwasher 10 has a hot water valve 14 that is connected to a domestic hot water supply 16. The dishwasher 10 has a heating element 18. The dishwasher 10 comprises a pump 20 that has a waste water discharge line 22. The controller 12 is connected to a temperature sensor 24, and is also connected to a door position switch 26. The controller 12 is also connected to the pump 20, hot water valve 14, and heating element 18.

(3) In an embodiment, the temperature sensor 24 is mounted at the coolest expected location, such as the bottom rear of the appliance. The sensor 24 activates the freeze protection function of the controller 12 once the ambient temperature fails to be just above the freezing point, for a safety margin. In an embodiment, the freezing point is approximately 37 degrees F.

(4) The control circuit 12 confirms the door is closed by door position switch 26 and admits hot water through hot water valve 14 to the dishwasher 10 for a period of time sufficient to allow heated water to travel from the home's water heater to the dishwasher 10.

(5) In an embodiment, the control circuit has an activation period of approximately two (2) minutes to be sufficient, however, another duration can be designed.

(6) The hot water valve 14 also admits hot water to operate an ordinary wash cycle. This will heat the dishwasher's supply line sufficiently to prevent freezing of this part of the system.

(7) In an embodiment, the hot water is provided to be ejected into the drain hose 22 via operation of the drain pump 20. In an embodiment, this function is accomplished by activating the pump 20 via the control 12 which is also used to conclude a rinse cycle. This will heat the dishwasher's pump 20 and drain line 22 sufficiently to prevent freezing of this part of the system.

(8) The heating element 18 in the appliance 10 is energized using the existing thermostatic controls used for dish drying. The element 18 remains in the heating mode until the temperature sensing component 24 returns an ambient temperature above the freezing point. In an embodiment, the ambient temperature is approximately 45 degrees F. At the point the sensing component 24 returns an ambient temperature above freezing point, the automatic freeze protection cycle is concluded.

(9) The device of the present invention when activated heats the dishwasher to a certain temperature above freezing. This protects the appliance, for significant periods of time, from damage due to a freeze of standing water in the pump 20, drain, and/or supply line as their systems re-cool. The duration of protection will depend on the ambient conditions of the general area.

(10) In an embodiment, the system of the present invention reactivates if the threat of freezing recurs as indicated by a fall in ambient temperature once again, for example, to 37 degrees F.

(11) In an embodiment, the automatic dishwasher has the automatic freeze protection incorporated into the appliance in either a manual or fully automatic mode.

(12) In an embodiment, the manual mode of the present invention requires the operator to engage the automatic freeze protection system if freezing temperatures are expected. The automatic mode operates in the background without user interaction to protect the appliance automatically.

(13) The present invention combines the use of a temperature sensor and minor control implementation, for the user of a dishwasher appliance to have their dishwasher protected from the expensive damage in the event the appliance is subjected to freezing temperatures.