US 4,175,418 AGranted

Temperature monitoring and temperature differential control device

AssigneeS. L. Steffen

InventorsSylvester L. Steffen, Duaine L. Bollwitt

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Abstract

An electronic device is provided for use in monitoring and controlling the curing of live food products, specifically grain, in a storage environment. The device includes a first temperature sensing unit, a second temperature sensing unit, a comparator unit, a temperature differential comparator unit and a load switch responsive thereto, and a digital display unit for displaying the monitored temperatures and temperature differentials.

Claims15

Dependent claims

Apparatus comprising:

first sensing means for determining the temperature of a first environment and for producing an output voltage corresponding to such temperature said first sensing means including a first operational amplifier having an inverting input, a non-inverting input and an output, a first voltage transducer unit having an output voltage, and first, second, third and fourth resistors each having a first lead and a second lead, such that the first lead of said first resistor is electrically connected to the output of said first voltage transducer unit and the second lead of said first resistor is electrically connected to the inverting input of said first operational amplifier, the first lead of said second resistor is electrically connected to the inverting input of said first operational amplifier and the second lead of said second resistor is electrically connected to the output of said first operational amplifier, the first lead of said third resistor is electrically connected to the non-inverting input of said first operational amplifier and the second lead of said third resistor is electrically connected to ground potential, the first lead of said fourth resistor is electrically connected to the non-inverting input of said first operational amplifier and the second lead of said fourth resistor is electrically negatively biased;
second sensing means for determining the temperature of a second environment and for producing an output voltage corresponding to such temperature said second sensing means including a second operational amplifier having an inverting input, a non-inverting input and an output, a second voltage transducer unit having an output, a fifth, sixth, seventh, and eighth resistors each having a first lead and a second lead, such that the first lead of said fifth resistor is electrically connected to the output of said second voltage transducer unit and the second lead of said fifth resistor is electrically connected to the inverting input of said second operational amplifier, the first lead of said sixth resistor is electrically connected to the output of said second operational amplifier, the first lead of said seventh resistor is electrically connected to the non-inverting input of said second operational amplifier and the second lead of said seventh resistor is electrically connected to ground potential, the first lead of said eighth resistor is electrically connected to the non-inverting input of said second operational amplifier and the second lead of said eighth resistor is electrically negatively biased;
first comparator means operably connected to said first and second sensing means for comparing the voltage outputs therefrom and for producing an output voltage corresponding to the temperature differential between the first and second environment;
adjustable reference means for selectively providing an output voltage corresponding to a desired temperature differential;
second comparator means operably connected to said first comparator means and said adjustable reference means for comparing the voltage outputs therefrom and for producing a hysteresis type of "High" or "Low" switching output voltage corresponding to the difference between (a) the temperature differential between the first and second environment, and (b) the desired temperature differential;
a load switch for activating a load responsive to the "High" and "Low" voltage output of said second comparator means;
a display switch selectively and operably connected to the output of said first sensing means, the output of said second sensing means and the output of said first comparator means;
and
a display means operably connected to said display switch for producing a visual display of the temperature of the first environment, the temperature of the second environment and the temperature differential between the first and second environment, said display means including means for producing a visual display of the temperature in degrees Fahrenheit.

6 more elements

A method of using grain curing apparatus comprising first sensing means for determining the temperature of a first environment and for producing an output voltage corresponding to such temperature;

second sensing means for determining the temperature of a second environment and for producing an output voltage corresponding to such temperature;
first comparator means operably connected to said first and second sensing means for comparing the voltage outputs therefrom and for producing an output voltage corresponding to the temperature differential between the first and second environment;
adjustable reference means for selectively providing an output voltage corresponding to a desired temperature differential;
second comparator means operably connected to said first comparator means and said adjustable reference means for comparing the voltage outputs therefrom and for producing a hysteresis type of "High" or "Low" switching output voltage corresponding to the difference between (a) the temperature differential between the first and second environment, and (b) the desired temperature differential;
and a load switch for activating a load responsive to the "High" or "Low" voltage output of said second comparator means;
said method comprising the steps of:
monitoring the temperature of air in a first environment prior to its being introduced into the stored grain;
monitoring the temperature of air passing from grain in a second environment;
and
monitoring the temperature difference between the air in the first environment and the air in the second environment.

7 more elements

Dependencies are inferred from the claim text.

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Abstract

Apparatus comprising:

first sensing means for determining the temperature of a first environment and for producing an output voltage corresponding to such temperature said first sensing means including a first operational amplifier having an inverting input, a non-inverting input and an output, a first voltage transducer unit having an output voltage, and first, second, third and fourth resistors each having a first lead and a second lead, such that the first lead of said first resistor is electrically connected to the output of said first voltage transducer unit and the second lead of said first resistor is electrically connected to the inverting input of said first operational amplifier, the first lead of said second resistor is electrically connected to the inverting input of said first operational amplifier and the second lead of said second resistor is electrically connected to the output of said first operational amplifier, the first lead of said third resistor is electrically connected to the non-inverting input of said first operational amplifier and the second lead of said third resistor is electrically connected to ground potential, the first lead of said fourth resistor is electrically connected to the non-inverting input of said first operational amplifier and the second lead of said fourth resistor is electrically negatively biased;
second sensing means for determining the temperature of a second environment and for producing an output voltage corresponding to such temperature said second sensing means including a second operational amplifier having an inverting input, a non-inverting input and an output, a second voltage transducer unit having an output, a fifth, sixth, seventh, and eighth resistors each having a first lead and a second lead, such that the first lead of said fifth resistor is electrically connected to the output of said second voltage transducer unit and the second lead of said fifth resistor is electrically connected to the inverting input of said second operational amplifier, the first lead of said sixth resistor is electrically connected to the output of said second operational amplifier, the first lead of said seventh resistor is electrically connected to the non-inverting input of said second operational amplifier and the second lead of said seventh resistor is electrically connected to ground potential, the first lead of said eighth resistor is electrically connected to the non-inverting input of said second operational amplifier and the second lead of said eighth resistor is electrically negatively biased;
first comparator means operably connected to said first and second sensing means for comparing the voltage outputs therefrom and for producing an output voltage corresponding to the temperature differential between the first and second environment;
adjustable reference means for selectively providing an output voltage corresponding to a desired temperature differential;
second comparator means operably connected to said first comparator means and said adjustable reference means for comparing the voltage outputs therefrom and for producing a hysteresis type of "High" or "Low" switching output voltage corresponding to the difference between (a) the temperature differential between the first and second environment, and (b) the desired temperature differential;
a load switch for activating a load responsive to the "High" and "Low" voltage output of said second comparator means;
a display switch selectively and operably connected to the output of said first sensing means, the output of said second sensing means and the output of said first comparator means;
and
a display means operably connected to said display switch for producing a visual display of the temperature of the first environment, the temperature of the second environment and the temperature differential between the first and second environment, said display means including means for producing a visual display of the temperature in degrees Fahrenheit.

6 more elements