Bi-modal temperature controller
AssigneeWestern Electric Company, Inc.
InventorMark S. Burroughs
Life of this patent
Estimating the term…
Abstract
A temperature controller senses whether the temperature of a body (30) is higher or lower than a desired temperature, and then heats or cools the body (30) in either a high power mode or a low power mode. The controller operates in the low power mode if the elapsed time from the last change from heating to cooling or cooling to heating is less than a predetermined time interval. This condition typically occurs when the temperature of the body (30) is near the desired temperature, i.e., the controller is switching back and forth from heating to cooling in fairly short time intervals. If the elapsed time is longer than the predetermined time interval, as typically occurs when the temperature of the body (30) is being changed to a new desired temperature, the controller operates in the high power mode.
Claims10
Apparatus for controlling the temperature of a body comprising:
- (a) means for detecting whether the temperature of the body is greater than or less than a desired temperature and for generating a status signal to indicate whether the body temperature is greater than or less than said desired temperature;
- (b) timing means for determining whether said status signal has remained constant for a predetermined time interval;
- (c) means for generating at least a first and second pulse train, said first pulse train having a duty cycle which is less than the duty cycle of said second pulse train;
- (d) means for coupling said first pulse train to a signal node when said timing means determines that said status signal has not remained constant during said time interval, and for coupling said second pulse train to said signal node when said timing means determines that said status signal has remained constant during said time interval;
- and
- (e) means for heating or cooling said body in response to said status signal and at a power level related to the duty cycle of the signal coupled to said signal node.
Apparatus as recited in clam 1 wherein said timing means includes first means for timing a first predetermined interval in response to a change in status signal from a digital 1 to a digital 0 and second means for timing a second predetermined interval in response to a change in status signal from a digital 0 to a digital 1.
A method for controlling the temperature of a body comprising the steps of:
- (a) generating a digital status signal which indicates whether the temperature of the body is greater than or less than a desired temperature;
- (b) timing an interval following each change of said digital status signal;
- (c) generating a first pulse train and a second pulse train, said first pulse train having a duty cycle which is less than the duty cycle of said second pulse train;
- (d) passing said first pulse train to a signal node prior to expiration of the time interval;
- (e) passing said second pulse train to said signal node after expiration of the time interval;
- and
- (f) heating or cooling the body in response to said digital status signal and at a rate related to the duty cycle of the signal appearing at said signal node.
Dependencies are inferred from the claim text.