Method of heating a medium to a desired temperature

• US 6,018,150 A
• Filed: 12/30/1996
• Issued: 01/25/2000
• Est. Priority Date: 03/23/1995
• Status: Expired due to Term

• Current Assignee: Ametek Incorporated
• Original Assignee: Tridelta Industries, Inc. (Honeywell International Inc.)
• Inventors: Maher, Charles A. Jr.
• Primary Examiner(s): Paschall, Mark H.
• Application Number:
  US08/777,756
• Time in Patent Office: 1,121 Days
• Field of Search: 219/494, 219/497, 219/501, 219/505, 219/508, 219/441, 219/442, 99/325-334, 395/90
• US Class Current: 219/497
• CPC Class Codes: G05D 23/1913 delivering a series of pulses
• CPC Class Codes: G05D 23/1951 with control of the working time of a temperature controlling device

Abstract

A method for heating a medium in a heating apparatus comprising establishing a setpoint temperature for the medium, determining thermal characteristics of the heating apparatus and the medium during a first mode of operation, the thermal characteristics establishing an idle-on pulse duration for raising the temperature of the medium a first amount, generating at a move-to-idle temperature a move-to-idle pulse of heat having a move-to-idle pulse duration, the move-to-idle pulse duration being sufficient to raise the temperature of the medium to a temperature above the setpoint temperature, wherein the move-to-idle pulse duration is derived from the idle-on pulse duration and the deviation between the setpoint temperature and the move-to-idle temperature.

Claims

1. A temperature control system for a heating apparatus comprising:

input means for establishing a setpoint temperature for a medium;

heating means for heating said medium;

sensing means for determining the temperature of the medium;

control means for controlling the amount of heat provided to the medium by the heating means, said control means including a move-to-idle mode of operation for initiating a single pulse of heat to move the temperature of the medium from a temperature below said setpoint temperature to a temperature above said setpoint temperature, wherein during said move-to-idle mode said control means causes said heating means to generate a move-to-idle pulse of heat having a move-to-idle pulse duration sufficient to bring said medium to a temperature above said setpoint temperature from a move-to-idle temperature which is below said setpoint temperature, said control means deriving said move-to-idle pulse duration from thermal characteristics of said heating apparatus and said medium obtained during an earlier operating mode.

2. A temperature control system according to claim 1, wherein said control means further comprises:

means for determining said thermal characteristics of said heating apparatus and said medium by adjusting an idle-on pulse of heat having an idle-on pulse duration, said idle-on pulse generated each time the medium changes from a temperature above an idle-on temperature to a temperature below the idle-on temperature, such that the temperature of the medium remains within a predetermined temperature range about the setpoint temperature.

3. A temperature control system according to claim 2, wherein said control means derives said move-to-idle pulse duration according to the equation:

##EQU2## wherein MTIP is said move-to-idle pulse duration,

IOP is said idle-on pulse duration,

T_SETPOINT is said setpoint temperature,

T_MTI is said pulse temperature, and

K is the temperature change resulting from said idle-on pulse.

4. A temperature control system according to claim 3, wherein K is a constant and derived from the temperature range resulting from generation of the idle-on pulse of heat.

5. A temperature control system for a heating apparatus comprising:

input device for inputting a setpoint temperature for a medium;

heating element for heating said medium;

temperature sensor for determining the temperature of the medium;

a controller for controlling the amount of heat provided to the medium by the heating element, said controller having a plurality of modes of operation including a move-to-idle mode of operation for moving the temperature of said medium from a temperature below said setpoint temperature to a temperature above said setpoint temperature, wherein said controller causes said heating element to generate a move-to-idle pulse of heat having a move-to-idle pulse duration sufficient to bring said medium to a temperature above said setpoint temperature from a move-to-idle temperature which is below said setpoint temperature, said controller deriving said move-to-idle pulse duration from thermal characteristics of said heating apparatus and medium determined during one of said plurality of modes of operation.

6. A temperature control system according to claim 5, wherein said controller further comprises a first circuit for determining said thermal characteristics of said medium by adjusting an idle-on pulse of heat having an idle-on pulse duration, said idle-on pulse generated each time the medium changes from a temperature above an idle-on temperature to a temperature below the idle-on temperature, such that the temperature of the medium remains within a predetermined temperature range about the setpoint temperature.

7. A temperature control system according to claim 6, wherein said controller derives said move-to-idle pulse duration according to the equation:

##EQU3##

8. A temperature control system according to claim 7, wherein K is derived from the temperature range resulting from generation of the idle-ON pulse of beat.

9. A method for heating a medium in a heating apparatus comprising:

establishing a setpoint temperature for the medium,

determining thermal characteristics of the heating apparatus and the medium during a first mode of operation, said thermal characteristics establishing an idle-on pulse duration for raising the temperature of the medium a first amount;

generating at a move-to-idle temperature a move-to-idle pulse of heat having a move-to-idle pulse duration, said move-to-idle pulse duration being sufficient to raise the temperature of the medium to a temperature above the setpoint temperature, wherein the move-to-idle pulse duration is derived from said idle-on pulse duration and the deviation between the setpoint temperature and the move-to-idle temperature.

10. A method of heating according to claim 9, wherein said thermal characteristics of said heating apparatus and said medium are determined through the process of adjusting the idle-on pulse duration of an idle-on pulse of heat, generated each time the medium changes from a temperature above an idle-on temperature to a temperature below the idle-on temperature, such that the temperature of the medium remains within a predetermined temperature range about the setpoint temperature.

11. A method of heating according to claim 10, wherein said move-to-idle pulse duration is derived from the equation:

##EQU4## wherein MTIP is said move-to-idle pulse duration,

IOP is said idle-on pulse duration,

T_SETPOINT is said setpoint temperature,

T_MTI is said pulse temperature, and

K is the temperature change resulting from said idle-on pulse.

12. A method of heating according to claim 11, wherein K is a constant and is derived from the temperature range resulting from generation of the idle-ON pulse of heat.

13. A temperature control system for heating a medium in a heating apparatus comprising:

means for applying heat to a medium in each of a plurality of operating modes;

means for determining thermal characteristics of the heating apparatus and the medium during a first mode of said plurality of operating modes;

means for adjusting the temperature of said medium in accordance with the thermal characteristics in a second mode of said plurality of operating modes, wherein said means for adjusting raises the medium temperature above a predetermined temperature with a single pulse of heat determined based upon said thermal characteristics of the heating apparatus and the medium determined during said first mode.

14. A temperature control system for heating a medium, comprising:

a heating element for heating said medium;

a temperature sensor for determining the temperature of said medium;

a controller for controlling said heating element, said controller having;

a first operating mode for establishing a first steady state operating condition, wherein a first pulse of heat of known duration is determined to effect a desired temperature change by said medium, said temperature change and said first pulse being indicative of the thermal response characteristics of said cooking medium at that time, and

a second operating mode for generating a second pulse of heat to effect a temperature rise in said cooking medium from a first temperature to a second temperature, the duration of said second pulse of heat being determined by said first pulse of heat and said desired temperature rise.

15. A temperature control system for a heating apparatus comprising:

an input device for establishing a setpoint temperature for a medium;

a heating device for heating said medium;

a sensing device for determining the temperature of the medium;

a controller for controlling the amount of heat provided to the medium by the heating device, said controller having a plurality of operating modes including a move-to-idle mode, wherein said controller in said move-to-idle mode causes said heating device to generate a move-to-idle pulse of heat having a move-to-idle pulse duration sufficient to bring said medium to a temperature above said setpoint temperature from a move-to-idle temperature which is below said setpoint temperature, and means for storing a plurality of move-to-idle pulse durations and the corresponding medium temperature rise value for each move-to-idle pulse duration, wherein for subsequent operations of said move-to-idle mode said controller extrapolates an appropriate move-to-idle pulse duration from said plurality of move-to-idle pulse durations and the corresponding medium temperature rise values.

16. A method for heating a medium in a heating apparatus comprising:

establishing a setpoint temperature for a medium;

controlling the amount of heat provided to the medium during a move-to-idle move of operation, wherein a move-to-idle pulse of heat having a move-to-idle pulse duration is generated to cause a change in temperature of said medium wherein said medium changes to a temperature above said setpoint temperature from a move-to-idle temperature below said setpoint temperature;

storing said pulse duration and said change in temperature in a table of data including a plurality of move-to-idle pulse duration values and a plurality of change in temperature values;

extrapolating from said table of data a move-to-idle pulse duration for a move-to-idle temperature during a subsequent move-to-idle mode of operation, wherein said move-to-idle pulse duration extrapolated from said table of data is sufficient to raise the temperature of the medium to a temperature above the setpoint temperature;

generating a pulse of heat having said move-to-idle pulse duration.

17. A method of heating a medium in a heating apparatus comprising the steps of:

controlling a heating device to establish a steady state operation, wherein periodic pulses of heat maintain the temperature within a predetermined range of temperatures, and wherein each of said pulses of heat produces a generally similar change in the temperature of said medium;

determining from said steady state operation a thermal characteristic of said medium; and

generating a pulse of heat of specific duration to raise the temperature of said medium from a first temperature to a second temperature, said specific duration determined based upon the thermal characteristic of said medium.