WATER TANK HEATER WITH PREDICTIVE HEATER FAILURE FEATURE

• US 20110095010A1
• Filed: 10/23/2009
• Published: 04/28/2011
• Est. Priority Date: 10/23/2009
• Status: Abandoned Application

• Current Assignee: Premark FEG LLC (Illinois Tool Works Inc.)
• Original Assignee: Premark FEG LLC (Illinois Tool Works Inc.)
• Inventors: Schlieper, William C., Padtberg, Klaus, Bondarowicz, Frank A., Varacins, Alan J., Fabin, Joseph E.
• Application Number:
  US12/605,009
• Publication Number:
  US 20110095010A1
• Time in Patent Office: Days
• US Class Current: 219/209
• CPC Class Codes: F24H 1/202 with resistances
• CPC Class Codes: F24H 15/104 Inspection; Diagnosis; Trial operation
• CPC Class Codes: F24H 15/37 of electric heaters
• CPC Class Codes: F24H 15/395 Information to users, e.g. alarms
• CPC Class Codes: F24H 15/414 using electronic processing, e.g. computer-based
• CPC Class Codes: F24H 9/2021 Storage heaters

Abstract

A water heating system includes a tank for holding water and a resistive heating element associated with the tank for heating water in the tank. A control is connected for monitoring at least one resistance parameter of the resistive heating element as power is applied to the resistive heating element, the control configured to output a fault signal if the monitored resistance parameter exceeds a set threshold. The monitored parameter may be one or more of (i) a rate of resistance change during heater start-up, (ii) a rate of resistance change during steady state heater operation or (iii) a heater resistance corresponding to a set point in time following heater start-up.

Claims

1. A water heating system, comprising:

a tank for holding water;

a resistive heating element associated with the tank for heating water in the tank;

a control connected for monitoring at least one resistance parameter of the resistive heating element as power is applied to the resistive heating element, the control configured to output a fault signal if the monitored resistance parameter exceeds a set threshold.

2. The water heating system of claim 1, wherein the resistance parameter is one or more of (i) a rate of resistance change during heater start-up, (ii) a rate of resistance change during steady state heater operation or (iii) a heater resistance corresponding to a set point in time following heater start-up.

3. The water heating system of claim 1, wherein the control monitors both applied heater voltage and actual heater current when monitoring the resistance parameter, and determines resistance values therefrom.

4. The water heating system of claim 1, wherein applied heater voltage is constant, the control monitors actual heater current and determines resistance values therefrom.

5. The water heating system of claim 1 wherein the set threshold is established in accordance with a calibration procedure of the control and is stored in memory of the control.

6. The water heating system of claim 5 wherein the set threshold is established as a specified departure of the monitored resistance parameter from a level of the monitored resistance parameter determined during the calibration procedure.

8. The water heating apparatus of claim 6 wherein the set threshold identifies a degraded non-failure state of the resistive heating element.

9. The water heating apparatus of claim 1 wherein the set threshold corresponds to a non-immersed state of the resistive heating element.

10. The water heating system of claim 1 wherein the water heating system is incorporated into a dishwasher apparatus, and the tank comprises one of (i) a booster heater tank for heating rinse water prior to spraying of rinse water or (ii) a recirculation tank including a recirculation line for delivering water from the tank to spray nozzles for spraying, the sprayed water returning to the tank after spraying.

11. The water heating system of claim 1 wherein the water heating system is incorporated into a steam oven including a steam cooking chamber, the tank defined by a steam generator tank having an outlet plumbed to deliver steam to the steam cooking chamber.

12. The water heating system of claim 1 wherein the fault signal effects one of (i) shut down of power to the resistive heating element or (ii) operation of the resistive heating element at a reduced power level.

13. The water heating system of claim 1 where the fault signal effects operation of an operator annunciator.

14. The water heating system of claim 13 wherein the operator annunciator comprises at least one of a light element, an audio element or a communication device signal.

15. The water heating system of claim 1 wherein the fault signal effects operation of an automated delime operation in the tank.

16. The water heating system of claim 1 wherein the fault signal is stored in memory for subsequent reading via a communications interface and/or is sent to a communication channel.

17. The water heating system of claim 1 wherein the set threshold is a first set threshold, the fault signal is a first fault signal that effects operation of an operator annunciator, the control is configured to output a second fault signal if the monitored resistance parameter exceeds a second set threshold, the second set threshold higher than the first set threshold, the second fault signal effecting shut down of power to the resistive heating element.

18. The water heating system of claim 1 wherein;

the resistance parameter is one or more of (i) a rate of resistance change during heater start-up, (ii) a rate of resistance change during steady state heater operation or (iii) a heater resistance corresponding to a set point in time following heater start-up;

the control monitors one or both of applied heater voltage and actual heater current when monitoring the resistance parameter, and determines resistance values therefrom;

the set threshold is established in accordance with a calibration procedure of the control and is stored in memory of the control;

the water heating system is incorporated into one of;

a dishwasher apparatus, and the tank comprises one of (i) a booster heater tank for heating rinse water prior to spraying of rinse water or (ii) a recirculation tank including a recirculation line for delivering water from the tank to spray nozzles for spraying, the sprayed water returning to the tank after spraying;

or

a steam oven including a steam cooking chamber, the tank defined by a steam generator tank having an outlet plumbed to deliver steam to the steam cooking chamber.

19. In a water heating system including a tank for holding water, a resistive heating element within the tank for heating water in the tank, and a control associated with the resistive heating element, a method of identifying a degraded non-failure state of the resistive heating element, comprising:

monitoring at least one resistance parameter of the resistive heating element as power is applied to the resistive heating element, and producing a fault signal if the monitored resistance parameter exceeds a set threshold that is indicative of the degraded non-failure state.

20. The method of claim 19 wherein the resistance parameter is one or more of (i) a rate of resistance change during heater start-up, (ii) a rate of resistance change during steady state heater operation or (iii) a heater resistance corresponding to a set point in time following heater start-up.

21. A heating system, comprising:

a resistive heating element;

a control connected for monitoring at least one resistance parameter of the resistive heating element as power is applied to the resistive heating element, the control configured to output a fault signal if the monitored resistance parameter exceeds a set threshold that is indicative of a degraded non-failure state of the resistive heating element.

22. The heating system of claim 21, wherein the resistance parameter is one or more of (i) a rate of resistance change during heater start-up, (ii) a rate of resistance change during steady state heater operation or (iii) a heater resistance corresponding to a set point in time following heater start-up.

23. The heating system of claim 21 wherein the set threshold is established in accordance with a calibration procedure of the control and is stored in memory of the control.

24. The heating system of claim 23 wherein the set threshold is established as a specified departure of the monitored resistance parameter from a level of the monitored resistance parameter determined during the calibration procedure.