Excess air control with dual pressure switches
US4729207A · kind A · utility
69Cited by
3References
7Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 17, 1986 |
| Grant date | Mar 8, 1988 |
| Priority date | — |
| Expiry date | Sep 17, 2006 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF23N1/02
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
A method and apparatus for maintaining the desired level of excess air in a two stage gas furnace system. Low and high pressure switches are placed across the heat exchanger and are successively closed, as the inducer motor accelerates during purging, when the pressure drop reaches the respective theoretically desired low and high firing pressure drop levels. As the switches are closed, the inducer motor speeds are sensed and recorded, with a ratio of the two then being calculated. After firing, the ratio is then directly applied to a desired high firing motor speed to obtain the desired low firing motor speed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.