Uniform temperature control system

• US 6,402,042 B1
• Filed: 11/29/2000
• Issued: 06/11/2002
• Est. Priority Date: 11/29/2000
• Status: Expired due to Fees

• Current Assignee: Blue Earth Resources, Inc.
• Original Assignee: Blue Earth Resources, Inc.
• Inventors: Jaeger, Mark H., Lundgreen, Michael W., Hiniker, Thomas K., Schlosser, Thomas C., Stenzel, Jerry A.
• Primary Examiner(s): WAYNER, WILLIAM E
• Application Number:
  US09/725,152
• Publication Number:
  US 20020063164A1
• Time in Patent Office: 559 Days
• Field of Search: 700/8, 236/1.A, 236/20.R, 236/32, 236/33, 236/78.D, 165/286
• US Class Current: 236/33
• CPC Class Codes: F01P 2070/04 using electrical heating elements
• CPC Class Codes: F23N 2225/12 room temperature
• CPC Class Codes: F23N 5/027 using mechanical means F23N5/04 - F23N5/14 take precedence
• CPC Class Codes: G05D 23/1913 delivering a series of pulses

Abstract

The present invention relates to a control system for establishing and maintaining a desired uniform temperature in a room heated by a heating device. The control system includes a valve assembly for controlling the pressure of the fluid supplied to the heating device, the valve assembly including a valve actuator, a pressure sensor sensing the pressure of the fluid supplied to the heater, and a temperature control device to sense the ambient temperature of the room. The control system also includes an electronic control unit connected to the aforementioned elements, the electronic control unit including an electronic circuit which samples “open” and “close” input signals from the temperature control device, determines the rate of change of the pressure of the fluid from a predetermined pressure set point, and varies the pressure set point (which thereby varies the heating device output), according to the “open” or “close” signals by providing a command signal to the valve actuator. This command signal is based upon a difference between the predetermined desired temperature and the actual temperature, and the rate of change of the pressure of the fluid.

Claims

1. A control system for establishing and maintaining a desired uniform temperature in a room heated by a heating device, the control system comprising:

a) a valve assembly controlling a fluid supplied to the heating device, the valve assembly including a valve actuator;

b) at least one pressure sensor sensing the pressure of the fluid supplied to the heater;

c) at least one temperature control device which senses the ambient temperature in the room at first predetermined intervals, compares the ambient temperature to at least one predetermined temperature set point and if the ambient temperature differs from the temperature set point by a predetermined amount, issues a control signal;

d) an electronic control unit connected to the at least one temperature control device, the at least one pressure sensor and the valve actuator, the electronic control unit including an electronic circuit which receives the control signal from the temperature control device, determines the rate of change of the pressure of the fluid from a predetermined pressure set point, and varies the pressure set point in accordance with the control signal, thereby varying the heating device output, by providing a command signal to the valve actuator based upon a difference between the at least one predetermined temperature set point and the actual temperature, and the rate of change of the pressure of the fluid.

2. The control system of claim 1 wherein the electric circuit includes:

a central processing unit (CPU) connected to the at least one pressure sensor so as to sample a pressure signal from the at least one pressure sensor that is indicative of the pressure of the fluid at second predetermined intervals, the CPU including a comparator to receive the sampled pressure signals and to compare the received pressure signals to a predetermined pressure set point to determine the rate of change of the pressure.

3. The control system of claim 2 wherein the second predetermined intervals for sampling the pressure signals are adjustable.

4. The control system of claim 3 wherein the second predetermined intervals are no greater than 10 seconds.

5. The control system of claim 1 wherein the at least one predetermined temperature set point comprises an upper temperature set point and a lower temperature set point.

6. The control system of claim 1 wherein the first predetermined intervals for sampling the ambient temperature are adjustable.

7. The control system of claim 6 wherein the first predetermined intervals are no greater than 10 minutes.

8. The control system of claim 1 wherein the valve actuator comprises an on/off heat motor.

9. The control system of claim 8 wherein the electronic control unit is connected to the on/off heat motor and further comprises:

a) a power supply portion of the electronic circuit supplying predetermined nominal power to the on/off heat motor; and

b) a pulse width modulation register connected to the on/off heat motor so as to apply to the on/off heat motor a series of electrical pulses wherein the widths of the electrical pulses are modulated to control opening and closing of the valve assembly.