Analog pulsed heat trace monitor or the like
First Claim
1. A monitored heating system which comprises:
- (1) an AC power source(2) an elongate heater comprising two elongate electrodes which are connected to the power source, and a plurality of resistive heating elements connected in parallel with each other between the electrodes;
(3) a temperature-sensing means for sensing the temperature of a substrate heated by the heater at a first location;
(4) a signal generator which(a) is associated with the temperature-sensing means,(b) is powered, through the electrodes, by the AC power source;
(c) generates a pulsed DC signal having a pulse rate which is proportional to the temperature sensed by the temperature-sensing means, and(d) is coupled to the heater so that the pulsed signal is transmitted down one of the electrodes; and
(5) a receiver which is coupled to the heater at a second location and which produces a response which is dependent on the pulse rate of the pulsed signal.
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Accused Products
Abstract
A system, utilizing an analog pulsed signal, is for monitoring the condition of a system, by way of illustration, a multi-circuit electrically heat-traced substrate. The system senses the temperature of the substrate at the end of a heat traced circuit, converts the temperature to a pulsed signal, and drives the pulsed signal along the heat tracing to the control and distribution panel for the heat tracing in direct opposition to the AC which powers the heat tracing. A receiver converts the pulsed signal to a digital temperature read-out. Utilization of an analog pulsed signal enables the system to be used in a multi-circuit system without interference or signal mixing from adjacent circuits.
28 Citations
16 Claims
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1. A monitored heating system which comprises:
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(1) an AC power source (2) an elongate heater comprising two elongate electrodes which are connected to the power source, and a plurality of resistive heating elements connected in parallel with each other between the electrodes; (3) a temperature-sensing means for sensing the temperature of a substrate heated by the heater at a first location; (4) a signal generator which (a) is associated with the temperature-sensing means, (b) is powered, through the electrodes, by the AC power source; (c) generates a pulsed DC signal having a pulse rate which is proportional to the temperature sensed by the temperature-sensing means, and (d) is coupled to the heater so that the pulsed signal is transmitted down one of the electrodes; and (5) a receiver which is coupled to the heater at a second location and which produces a response which is dependent on the pulse rate of the pulsed signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A monitored heating system which comprises
(1) an AC power source; -
(2) a plurality of heating circuits which are connected in parallel with each other and each of which comprises (a) an elongate heater comprising two elongate electrodes which are connected to the power source, and a plurality of resistive heating elements connected in parallel with each other between the electrodes, (b) a temperature-sensing means for sensing the temperature of a substrate heated by the heater at a first location, (c) a signal generator which (i) is associated with the temperature sensing means, (ii) is powered by DC obtained by rectification of the AC output of the secondary winding of a transformer having a primary winding connected between the electrodes of the heater, (iii) generates a pulsed DC signal having a pulse rate which is proportional to the temperature sensed by the temperature-sensing means, and (iv) is coupled to the heater so that the pulsed signal is transmitted down one of the electrodes of the heater; and (d) a receiver which is coupled to the heater at a second location and which produces a response which is dependent on the pulse rate of the pulsed signal. - View Dependent Claims (15, 16)
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Specification