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US 12,099,074 B2Granted
Electronic proof of air flow switch
AssigneeEvolution Controls Inc.
InventorsDavid Lee Haessig, Joshua Lee Welton
Life of this patent
Estimating the term…
Abstract
A method and apparatus to electronically sense air flow and close a switch when air flow is adequate to operate an electric heater, HVACR system, or other apparatus. The apparatus is more reliable than electro-mechanical devices often used for this purpose.
Claims20
An EPAFS and probe apparatus for use in an HVACR system comprising:
- a diode probe comprising:
- a first sensing diode with a first junction voltage;
- and
- a second sensing diode with a second junction voltage;
- a half wave rectifier, wherein the half wave rectifier provides a heating pulse to heat the first sensing diode during a heating period and no heating pulse during a measuring period;
- a differential amplifier, wherein the differential amplifier measures a difference between the first junction voltage of the first sensing diode and the second junction voltage of the second sensing diode during the measuring period, and outputs a first output signal based on the difference between the first junction voltage and the second junction voltage;
- an inverter-amplifier circuit, wherein the inverter-amplifier circuit amplifies the first output signal from the differential amplifier and outputs a second output signal;
- a microcontroller, wherein the microcontroller compares the second output signal from the inverter-amplifier circuit to a threshold value;
- a switch for connecting to a forced air electric heating apparatus;
- and
- wherein the microcontroller is connected to the switch, and wherein the microcontroller turns off the switch when the second output signal exceeds the threshold value.
8 more elements
An EPAFS and probe apparatus for use in an HVACR system comprising:
- a diode probe comprising:
- a first sensing diode with a first junction voltage;
- and
- a second sensing diode with a second junction voltage;
- a half wave rectifier, wherein the half wave rectifier provides a heating pulse to heat the first sensing diode during a heating period and no heating pulse during a measuring period;
- a differential amplifier, wherein the differential amplifier measures a difference between the first junction voltage of the first sensing diode and the second junction voltage of the second sensing diode during the measuring period, and outputs a signal based on the difference between the first junction voltage and the second junction voltage;
- a sample and hold circuit, wherein the sample and hold circuit monitors the heating period and the measuring period to capture the signal during the measuring period and outputs a captured signal;
- a comparator, wherein the comparator compares the captured signal from the sample and hold circuit to a threshold value;
- a switch for connecting to a forced air electric heating apparatus;
- and
- wherein the comparator is connected to the switch, and wherein the comparator turns off the switch when the captured signal from the sample and hold circuit exceeds the threshold value.
8 more elements
An EPAFS and probe apparatus for use in an HVACR system comprising:
- a diode probe comprising:
- a first sensing diode string with a first series junction voltage comprising:
- a plurality of first sensing diodes;
- and
- wherein the plurality of first sensing diodes are connected in series;
- second sensing diode string with a second series junction voltage comprising:
- a plurality of second sensing diodes;
- and
- wherein the plurality of second sensing diodes are connected in series;
- and
- wherein each one of the plurality of first sensing diodes forms a sensing diode pair with one of the plurality of second sensing diodes to form a plurality of sensing diode pairs;
- and
- wherein the plurality of sensing diode pairs sense the average air flow;
- a half wave rectifier, wherein the half wave rectifier provides a heating pulse to heat the first sensing diode string during a heating period and no heating pulse during a measuring period;
- a differential amplifier, wherein the differential amplifier measures a difference between the first series junction voltage of the first sensing diode string and the second series junction voltage of the second sensing diode string during the measuring period, and outputs a first output signal based on the difference between the first series junction voltage and the second series junction voltage;
- an inverter-amplifier circuit, wherein the inverter-amplifier circuit amplifies the first output signal from the differential amplifier and outputs a second output signal;
- a microcontroller, wherein the microcontroller compares the second output signal from the inverter-amplifier circuit to a threshold value;
- a switch for connecting to a forced air electric heating apparatus;
- and
- wherein the microcontroller is connected to the switch, and wherein the microcontroller turns off the switch when the second output signal exceeds the threshold value.
17 more elements
An EPAFS and probe apparatus for use in an HVACR system comprising:
- a diode probe comprising:
- a first sensing diode string with a first series junction voltage comprising:
- a plurality of first sensing diodes;
- and
- wherein the plurality of first sensing diodes are connected in series;
- second sensing diode string with a second series junction voltage comprising:
- a plurality of second sensing diodes;
- and
- wherein the plurality of second sensing diodes are connected in series;
- and
- wherein each one of the plurality of first sensing diodes forms a sensing diode pair with one of the plurality of second sensing diodes to form a plurality of sensing diode pairs;
- and
- wherein the plurality of sensing diode pairs sense the average air flow;
- a half wave rectifier, wherein the half wave rectifier provides a heating pulse to heat the first sensing diode string during a heating period and no heating pulse during a measuring period;
- a differential amplifier, wherein the differential amplifier measures a difference between the first series junction voltage of the first sensing diode string and the second series junction voltage of the second sensing diode string during the measuring period, and outputs a first output signal based on the difference between the first series junction voltage and the second series junction voltage;
- a sample and hold circuit, wherein the sample and hold circuit monitors the heating period and the measuring period to capture the signal during the measuring period and outputs a captured signal;
- a comparator, wherein the comparator compares the captured signal from the sample and hold circuit to a threshold value;
- a switch for connecting to a forced air electric heating apparatus;
- and
- wherein the comparator is connected to the switch, and wherein the comparator turns off the switch when the second output signal exceeds the threshold value.
17 more elements
A remote air flow sensor for a fan inlet cone comprising:
- a printed circuit board, the printed circuit board comprising:
- a top side;
- a bottom side;
- a first conductor;
- a second conductor;
- and
- a third conductor;
- a first sensing diode mounted to the bottom side of the printed circuit board, the first sensing diode comprising:
- a first cathode connected to the first conductor;
- and
- a first anode connected to the second conductor;
- a second sensing diode mounted on the bottom side of the printed circuit board, the second sensing diode comprising:
- a second cathode connected to the first conductor;
- and
- a second anode connected to the third conductor;
- a plurality of standoffs for mounting the printed circuit board to a fan inlet cone for allowing air flow between the bottom side of the printed circuit board and the fan inlet cone;
- and
- wherein the first sensing diode and second sensing diode measure air flow between the bottom side of the printed circuit board and the fan inlet cone.
15 more elements
An EPAFS and probe apparatus for use in an HVACR system comprising:
- a diode probe comprising:
- a first sensing diode with a first junction voltage;
- a second sensing diode with a second junction voltage;
- and
- wherein the diode probe measures air flow leaving a refrigeration evaporator;
- a half wave rectifier, wherein the half wave rectifier provides a heating pulse to heat the first sensing diode during a heating period and no heating pulse during a measuring period;
- a differential amplifier, wherein the differential amplifier measures a difference between the first junction voltage of the first sensing diode and the second junction voltage of the second sensing diode during the measuring period, and outputs a first output signal based on the difference between the first junction voltage and the second junction voltage;
- an inverter-amplifier circuit, wherein the inverter-amplifier circuit amplifies the first output signal from the differential amplifier and outputs a second output signal;
- a microcontroller, wherein the microcontroller compares the second output signal from the inverter-amplifier circuit to a threshold value;
- a switch for connecting to a refrigeration equipment for controlling a defroster;
- and
- wherein the microcontroller is connected to the switch, and wherein the microcontroller turns off the switch when the second output signal exceeds the threshold value.
9 more elements
Dependencies are inferred from the claim text.