Temperature control system

Claim 2

A temperature control system for a constant temperature oven including in combination, first circuit means including a temperature sensitive element positioned in said oven for developing a first signal varying in amplitude in accordance with the deviation in temperature from a reference temperature within said oven, second circuit means including a first temperature adjusting means coupled to said first circuit means, said second circuit means operative to proportionally energize said first temperature adjusting means in response to said first signal amplitude, said second circuit means further including bias means and second temperature adjusting means, said bias means operative in response to said first signals in excess of a predetermined amplitude to proportionally energize said second temperature adjusting means.

Claim 3

The temperature control system of claim 1 wherein said first and second temperature adjusting means includes first and second heater elements for heating said oven.

Claim 4

The temperature control system of claim 1 wherein said first and second temperature adjusting means each including a heater element for heating said oven and, a transistor coupled to said heater element and operative in response to said first signal to proportionally energize said heater element.

Claim 5

The temperature control system of claim 3 wherein said bias means is a diode coupled to said first and second temperature adjusting means, said diode being operative in response to said first signals in excess of a predetermined amplitude to proportionally energize said second temperature adjusting means.

Claim 6

The temperature control system of claim 1 wherein said second circuit means includes: first semiconductor means coupled to said first circuit means and operative in response to said first signal to develop a first voltage which varies in accordance with said first signal, second semiconductor means coupled to said first heater element and said first semiconductor means, said second semiconductor means being operative in response to said first voltage to energize said first heater element in accordance with said first voltage variations, third semiconductor means coupled to said second heater element, diode means coupled to said first semiconductor means and said third semiconductor means, said diode means being operative in response to a first voltage in excess of a predetermined amount to proportionally energize said third semiconductor means, said third semiconductor means operative to proportionally energize said heater element in accordance with said first voltage variation in excess of said first predetermined amount.

Claim 7

The temperature control system of claim 5 wherein said temperature sensing means is a thermistor having a resistance which varies in accordance with the deviation in temperature from a reference temperature within said oven.

Claim 8

The temperature control system of claim 6 wherein said first circuit means includes an amplifier including said thermistor, said amplifier operative to develop oscillation signals varying in amplitude in accordance with the variations in said thermistor resistance, and detector means coupled to said amplifier means, said detector means developing said first signals in response to said oscillation signals.

Claim 9

A temperature control system for a constant temperature oven including in combination, amplifier means including temperature responsive means mounted in said oven, said amplifier means developing an oscillation signal which varies in accordance with the deviation in temperature within said oven from a reference temperature, rectifier circuit means coupled to said amplifier means for rectifying said oscillation signal and developing a first voltage which varies in amplitude in accordance with said oscillation signal, a temperature adjusting circuit including first and second heating means mounted in said oven, said temperature adjusting circuit being coupled to said rectifier cIrcuit means and operative in response to said first voltage to proportionally energize said first heater means, said temperature adjusting circuit further including bias means coupled to said second heating means and operative in response to said first voltage in excess of a predetermined amplitude to proportionally energize said second heater means, said first and second heating means heating said oven to maintain same at said reference temperature.

Claim 10

A temperature control system for a constant temperature oven including in combination, amplifier means including temperature responsive means mounted in said oven, said amplifier means developing an oscillation signal which varies in accordance with the deviation in temperature within said oven from a reference temperature, rectifier circuit means coupled to said amplifier means for rectifying said oscillation signal and developing a first voltage which varies in amplitude in accordance with said oscillation signal, a temperature adjusting circuit including first and second heating means mounted in said oven, said temperature adjusting circuit being coupled to said rectifier cIrcuit means and operative in response to said first voltage to proportionally energize said first heater means, said temperature adjusting circuit further including bias means coupled to said second heating means and operative in response to said first voltage in excess of a predetermined amplitude to proportionally energize said second heater means, said first and second heating means heating said oven to maintain same at said reference temperature.

Claim 11

The temperature control system of claim 8 wherein said temperature responsive means is a thermistor.

Claim 12

The temperature control system of claim 8 wherein said first and second heating means are heater elements.

Claim 13

The temperature control system of claim 9 wherein said amplifier means includes a bridge circuit including said thermistor, said bridge circuit being balanced when said oven temperature is the same as said reference temperature, said bridge circuit being unbalanced when said oven temperature varies from said reference temperature, the degree of unbalance of said bridge circuit varying in accordance with the deviation in temperature within said oven from said reference temperature, said amplifier means operative in response to said unbalance to develop said oscillation signals.

Claim 14

The temperature control system of claim 11 wherein said bias means is a diode.

Claim 15

The temperature control circuit of claim 12 wherein said temperature adjusting circuit includes: first semiconductor means coupled to said rectifier circuit means and operative in response to said first voltage to develop a second voltage which varies in amplitude in accordance with said first voltage, second semiconductor means coupled to said first semiconductor means and to said first heater element, said second semiconductor means operative in response to said second voltage amplitude to proportionally energize said first heater element, diode means coupled to said second semiconductor means, said diode means rendered conductive in response to said second voltage in excess of a predetermined amplitude, third semiconductor means coupled to said second heating means and said diode means said third semiconductor means being operative in response to conduction of said diode to proportionally energize said second heating means.