HEATING SYSTEM CONTROL

• US 3,665,159 A
• Filed: 10/19/1970
• Issued: 05/23/1972
• Est. Priority Date: 10/19/1970
• Status: Expired due to Term

• Current Assignee: Donald E. Knoop, Stephen A. Becker
• Original Assignee: Donald E. Knoop, Stephen A. Becker
• Inventors: Becker, Stephen A., Knoop, Donald E.
• Primary Examiner(s): Gilheany, Bernard A.
• Assistant Examiner(s): Bell, F. E.
• Application Number:
  US05/081,900
• Time in Patent Office: 582 Days
• Field of Search: 219/497,501,499,494
• US Class Current: 219/497
• CPC Class Codes: G05D 23/1909 whose output amplitude can only take two discrete values
• CPC Class Codes: G05D 23/24 the sensing element having a resistance varying with temperature, e.g. a thermistor

Abstract

A control for regulating an electric heater of a heating system to provide substantially maximum rate of elevation of the system temperature at start-up without overshooting a preselected temperature to which the system is to be heated. The control includes means for sensing the instantaneous difference between the system temperature and the preselected temperature and for performing control operations based on the sensed temperature information to provide the desired control of the heater. The control may be further arranged for selective use as an infinite heat control as desired.

Claims

1. In a heating system having an electric heater, a control for regulating the heater comprising:

means for sensing the temperature of the system; and

means for energizing the heater to bring the temperature of the system up to a preselected temperature and for regulating the energization of the heater subsequent to the system reaching said preselected temperature to maintain the system temperature substantially at said preselected temperature including (a) means responsive to the difference between the instantaneous temperature of the system sensed by said sensing means and said preselected temperature and (b) means responsive to the rate of change of said temperature difference effected by the energizing of said heater to terminate the energizing of the heater accurately prior to the sensed temperature reaching said preselected temperature to permit the heat capacity of the system to bring the temperature thereof accurately to said preselected temperature.

2. The heating system control of claim 1 wherein said energizing means is arranged To provide full power to said heater to bring the heater to said preselected temperature.

3. The heating system control of claim 1 wherein said energizing means comprises means for cycling the heater to maintain the system temperature within a preselected range at said preselected temperature.

4. The heating system control of claim 1 wherein said energizing means includes means for obtaining said temperature difference, means for obtaining the rate of change of said temperature difference, and means for comparing a combination of the temperature difference and the rate of change of the temperature difference with a reference to provide a regulating signal, and means for controlling the energization of the heater as a function of said signal.

5. The heating system control of claim 4 wherein said comparing means provides a series of pulses and said last named means comprises an electronic switching device responsive to said pulses.

6. The heating system control of claim 4 wherein said last named means comprises an electronic switch and said comparing means provides zero point switching of said electronic switch to bring said system temperature to said preselected temperature.

7. The heating system control of claim 1 wherein said energizing means includes means for obtaining said temperature difference;

means for obtaining the rate of change of said temperature difference;

means for amplifying said rate of change of said temperature difference, and adding the amplified rate of change of said temperature difference to said temperature difference to provide a regulating signal, and means for controlling the energization of the heater as a function of said signal.

8. The heating system control of claim 7 wherein said energizing means includes means for selectively bypassing said means for obtaining the rate of change of said temperature difference, whereby cooking loads of large heat capacity may be brought up to said preselected temperature in minimum time.

9. The heating system control of claim 8 wherein said bypassing means comprises switch means.

10. The heating system control of claim 1 wherein there is isolating transformer means provided for isolating the control from an electrical power supply to which the control is connected.

11. The heating system control of claim 1 including means for utilizing the control selectively to provide manually adjustable infinite control of the heater from zero energization to full energization.

12. The heating system control of claim 11 wherein said last name means comprises means for providing infinite adjustment of said regulating means.

13. In a heating system having an electric heater, a control for regulating the heater comprising:

means for setting a preselected temperature to be reached by the system;

means for sensing the temperature of the system;

means for obtaining the temperature difference between the instantaneous temperature of the system sensed by said sensing means and said preselected temperature;

means for energizing the heater to bring the temperature of the system up to the preselected temperature and for regulating the energization of the heater subsequent to the system reaching said preselected temperature to maintain the system temperature substantially at said preselected temperature including means for obtaining the rate of change of said temperature difference, means for amplifying said rate of change of said temperature difference, and adding the amplified rate of change of said temperature difference to said temperature difference to provide an output signal which is proportional to the sum of the temperature difference and the amplified rate of change of the temperature difference, and means for comparing said output signal with a reference voltage which is a function of the difference between the preselected temperature and the sensed temperature to provide a regulating signal to terminate the energizing of the heater accurately prior to the sensed teMperature reaching said preselected temperature to permit the heat capacity of the system to bring the temperature thereof accurately to said preselected temperature; and

means for controlling the energization of the heater as a function of said regulating signal.