Highly sensitive airflow direction sensing
First Claim
1. An airflow direction sensor comprising:
- an airflow passage for conducting air between different volumes;
a first temperature sensitive device adjacent to one end of said passage;
a second temperature sensitive device at an intermediate location in said passage;
a heat source at an opposite end of said passage; and
comparing means associated with said first and second temperature sensitive devices for comparing temperature sensed by each of said devices and providing an output indicative thereof.
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Abstract
Sensors, apparatus and methods are disclosed for detecting airflow direction between two volumes. The preferred airflow sensor includes a tube for conducting an airflow stream between the volumes, a first temperature sensor sensing ambient temperature in the first volume and a second temperature sensor sensing temperature of the airflow stream in the tube. A heat source heats air in the tube adjacent the end thereof communicating with the second volume and a comparator receives and compares output signals from the temperature sensors, providing an output indicative thereof. Various means are provided responsive to the output advancing appropriate response thereto. The disclosed sensors, apparatus and methods are particularly well adapted for indicating positive and negative pressure differentials at flues associated with combustion appliances.
29 Citations
20 Claims
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1. An airflow direction sensor comprising:
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an airflow passage for conducting air between different volumes; a first temperature sensitive device adjacent to one end of said passage; a second temperature sensitive device at an intermediate location in said passage; a heat source at an opposite end of said passage; and comparing means associated with said first and second temperature sensitive devices for comparing temperature sensed by each of said devices and providing an output indicative thereof. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A highly sensitive airflow sensing apparatus for indicating positive and negative pressure differentials at a flue associated with a combustion appliance located in a facility, said apparatus comprising:
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a tube for conducting an airflow stream, said tube having first and second open ends, said first open end in communication with ambient temperature air from the facility and said second open end in communication with the flue; a first temperature sensor providing an output signal and located adjacent to said first open end of said tube substantially out of contact with the airflow stream conducted by said tube, whereby said first temperature sensor is exposed to the ambient temperature in the facility; a second temperature sensor at an intermediate location in said tube and providing an output signal; a heat source in said tube adjacent to said second open end; a comparator receiving said output signals from said first and second temperature sensors, comparing said signals and providing an output indicative of comparison; and means responsive to said output from said comparator for advancing appropriate response to said output when indicative of irregular pressure differential at the flue. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A highly sensitive airflow direction sensing method comprising the steps of:
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conducting airflow in a passage between first and second volumes; sensing ambient temperature in said first volume; heating air at said passage adjacent said second volume; sensing temperature of said airflow being conducted in said passage; comparing sensed ambient temperature and sensed conducted airflow temperature; and providing an output indicative of compared ambient and conducted airflow temperatures. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification