US 4,393,300 AGranted

Heating control system

AssigneeEmhart Industries, Inc.

InventorGary R. Proctor

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Abstract

A temperature detecting heating control system provides a temperature sensor, first and second voltage comparators for detecting a set point temperature and a warning temperature, and alarm circuitry for producing intermittent and predetermined period alarm signals in response to the detecting of the warning temperature and set point temperature respectively.

Claims9

Dependent claims

A temperature detecting heating control system comprising:

a temperature sensor;
a first voltage comparator means having an output terminal and two input terminals;
first means for coupling said temperature sensor to one input terminal of said first comparator means;
a second voltage comparator means having an output terminal and two input terminals;
second means for coupling said temperature sensor to one input of said second comparator means;
means for generating a pair of dependently variable reference voltages, one of said reference voltages representing a variable set point temperature and being coupled to the other input terminal of said first comparator means, the other of said reference voltages representing a warning temperature, which is a predetermined number of degrees less than said set point temperature, and being coupled to the other input terminal of said second comparator means;
current switching semiconductor means coupled to the output terminal of said first comparator means for controlling heating power in response to the temperature of said sensor reaching said set point temperature;
alarm means for producing a tonal alarm signal;
and
means for controlling said alarm means in response to the temperature of said sensor, said means for controlling including means for causing said alarm means to produce an intermittent alarm signal in response to the temperature of said sensor being between said warning temperature and said set point temperature and a constant alarm signal for a predetermined period of time in response to the temperature of said sensor reaching said set point temperature,
said means for causing including third voltage comparator means having two input terminals and an output terminal coupled to control said alarm means,
said means for causing also including low frequency oscillator means coupled between said second comparator means output terminal and one input terminal of said third comparator means for intermittently activating said alarm means and having disabling means coupled to said first comparator means output terminal for disabling said oscillator means when said temperature of said sensor reaches said set point temperature,
said means for causing also including gate means for enabling activation of said alarm means only when the temperature of said sensor is between said warning temperature and said set point temperature,
said means for causing further including means coupled to said third comparator means other input terminal for maintaining activation of said alarm means for said predetermined time period after the temperature of said sensor reaches said set point temperature.

11 more elements

Dependencies are inferred from the claim text.

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Abstract

A temperature detecting heating control system comprising:

a temperature sensor;
a first voltage comparator means having an output terminal and two input terminals;
first means for coupling said temperature sensor to one input terminal of said first comparator means;
a second voltage comparator means having an output terminal and two input terminals;
second means for coupling said temperature sensor to one input of said second comparator means;
means for generating a pair of dependently variable reference voltages, one of said reference voltages representing a variable set point temperature and being coupled to the other input terminal of said first comparator means, the other of said reference voltages representing a warning temperature, which is a predetermined number of degrees less than said set point temperature, and being coupled to the other input terminal of said second comparator means;
current switching semiconductor means coupled to the output terminal of said first comparator means for controlling heating power in response to the temperature of said sensor reaching said set point temperature;
alarm means for producing a tonal alarm signal;
and
means for controlling said alarm means in response to the temperature of said sensor, said means for controlling including means for causing said alarm means to produce an intermittent alarm signal in response to the temperature of said sensor being between said warning temperature and said set point temperature and a constant alarm signal for a predetermined period of time in response to the temperature of said sensor reaching said set point temperature,
said means for causing including third voltage comparator means having two input terminals and an output terminal coupled to control said alarm means,
said means for causing also including low frequency oscillator means coupled between said second comparator means output terminal and one input terminal of said third comparator means for intermittently activating said alarm means and having disabling means coupled to said first comparator means output terminal for disabling said oscillator means when said temperature of said sensor reaches said set point temperature,
said means for causing also including gate means for enabling activation of said alarm means only when the temperature of said sensor is between said warning temperature and said set point temperature,
said means for causing further including means coupled to said third comparator means other input terminal for maintaining activation of said alarm means for said predetermined time period after the temperature of said sensor reaches said set point temperature.

11 more elements