TEMPERATURE CONTROLLERS

• US 3,612,165 A
• Filed: 11/12/1969
• Issued: 10/12/1971
• Est. Priority Date: 11/12/1968
• Status: Expired due to Term

• Current Assignee: Anthony Charles Rendell Haynes
• Original Assignee: Anthony Charles Rendell Haynes
• Inventors: Haynes, Anthony Charles Rendell
• Primary Examiner(s): Sukalo, Charles
• Application Number:
  US04/875,630
• Time in Patent Office: 699 Days
• Field of Search: 161/26,27
• US Class Current: 165/264
• CPC Class Codes: B29B 7/823 Temperature control
• CPC Class Codes: B29C 2948/92209 Temperature
• CPC Class Codes: B29C 2948/92295 Errors or malfunctioning, e.g. for quality control
• CPC Class Codes: B29C 2948/924 Barrel or housing
• CPC Class Codes: B29C 2948/92542 Energy, power, electric current or voltage
• CPC Class Codes: B29C 2948/92704 Temperature
• CPC Class Codes: B29C 2948/92895 Barrel or housing
• CPC Class Codes: B29C 2948/9298 Start-up, shut-down or parameter setting phase; Emergency shut-down; Material change; Test or laboratory equipment or studies
• CPC Class Codes: B29C 48/03 characterised by the shape of the extruded material at extrusion
• CPC Class Codes: B29C 48/92 Measuring, controlling or regulating
• CPC Class Codes: G05D 23/1906 using an analogue comparing device
• CPC Class Codes: G05D 23/22 the sensing element being a thermocouple

Abstract

A temperature controller for maintaining temperature at a set point, controls both heating and cooling. Means responsive to a temperature-error signal provide a first output including proportional and integral terms or proportional, integral and derivative terms. This signal is utilized to control heating power and means are provided operative when the heating power is less than a predetermined proportion of the maximum to provide a second output signal for controlling the cooling power. The second output signal is derived directly or indirectly from the first output signal or directly or indirectly from an initiating signal producing the first output signal so that the cooling power increases from a minimum to a predetermined level as the heating power falls from said predetermined level to a minimum.

Claims

1. A temperature controller for maintaining temperature at a set point comprising means responsive to a temperature-error signal to provide a first output including at least proportional and integral terms, means utilizing said first output to control heating power, means responsive to said first output to provide a second output signal varying with temperature when the heating power is less than a predetermined proportion of the maximum, and means responsive to said second output signal to control the cooling power so that the cooling power increases from a minimum to a predetermined level as the heating power falls from said predetermined level to a minimum.

2. A temperature controller as claimed in claim 1 wherein the second output signal increases the cooling from zero to a maximum as the heating power falls from said predetermined level to a minimum.

3. A temperature controller as claimed in claim 1 wherein said second output is inversely proportional to the first output over a chosen portion of the heating power band.

4. A temperature controller as claimed in claim 1 wherein said means for utilizing said first output to control heating power is operative to adjust the heating power from a minimum to a maximum over a chosen fraction of the total range of said first output and wherein the second output signal controlling the cooling power is derived from the first output to increase the cooling power from a minimum to a predetermined level as the heating power falls from said predetermined level to a minimum and to increase the cooling power to a maximum with further change of said first output after the heating power has fallen to said minimum.

5. A temperature controller as claimed in claim 1 wherein the heating power is nonlinearly related to the first output signal.

6. A temperature controller as claimed in claim 1 wherein the control of the heating is by a stepless proportional control.

7. A temperature controller as claimed in claim 1 wherein the control of the heating is by on/off time proportioning control.

8. A temperature controller as claimed in claim 1 wherein the control of the cooling is by stepless proportional control.

9. A temperature controller as claimed in claim 1 wherein the control of the cooling is by time proportioning on/off control.

10. A temperature controller as claimed in claim 1 and comprising an electronic controller wherein thyristors are provided for controlling the heating power in accordance with said first output.

11. A temperature controller as claimed in claim 10 wherein said first output is arranged to cause the thyristors to fire for complete cycles or half cycles of an alternating current power supply during the appropriate proportion of the alternating current cycles to obtain the required heating power output.

12. A temperature controller as claimed in claim 1 wherein the control of cooling is effected by means of a proportional valve controlling the flow of a coolant.

13. A temperature controller as claimed in claim 1 wherein adjusting means are provided for adjusting the range of said first output over which the cooling means are operative.

14. A temperature controller as claimed in claim 1 wherein means are provided for giving a warning signal if the cooling means are open to the fullest extent.

15. A temperature controller as claimed in claim 1 and for use where the maximum cooling power requirements are greater than the maximum heating power requirements wherein said first output from the controller is used to control the cooling instead of the heating and wherein the second output is used to control the heating instead of the cooling.

16. A temperature controller for maintaining temperature aT a set point comprising means responsive to a temperature-error signal over a predetermined temperature range to provide a first output including at least proportional and integral terms, means responsive to the first output signal to provide a second output signal varying with temperature over part only of said predetermined temperature range, means utilizing one of said first and second output signals to control heating power, and means utilizing the other of said output signals to control cooling power.