Air flow sensor using measurement of rate of heat loss
US6763711B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 15, 1999 |
| Grant date | Jul 20, 2004 |
| Priority date | — |
| Expiry date | Oct 15, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F1/696
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An air flow sensor including a temperature dependent resistor device, a first circuit and a second circuit. The first circuit applies a voltage to the temperature dependent resistor device until it reaches a first temperature. The first circuit includes a first reference resistance leg, a first variable resistance leg including the temperature dependent resistor device, and a first comparator connected to both legs for determining when the temperature dependent resistor device reaches the first temperature. The second circuit includes a second reference resistance leg, a second variable resistance leg including the temperature dependent resistor device, and a second comparator connected to both legs for determining when the temperature dependent resistor device reaches a second temperature. A processor is connected to both the first and second comparators and programmed to time the period of time it takes the temperature dependent resistor device to change from the first temperature to the second temperature to determine the heat loss rate of the temperature dependent resistor device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.