Smoke detector
US4564762A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 16, 1984 |
| Grant date | Jan 14, 1986 |
| Priority date | — |
| Expiry date | May 16, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B17/113
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An ionization detector unit for use in a smoke detector includes a housing wall enclosing an ionization chamber, the wall having openings for passage of air through the chamber, the frontal surface of the wall that is exposed to an oncoming air flow from a given direction being inclined relative to an intersecting second surface exposed to the flow. The frontal surface is shaped and positioned to deflect the air flow generally toward the second surface, and the second surface is shaped and positioned to deflect the air flow generally toward the frontal surface, the shape and position of the surfaces cooperatively arranged to cause the deflected air flows to converge and form a region of air in the vicinity of the intersection of the surfaces that is at higher pressure and slower velocity than the oncoming air flow. Apertures are provided in the frontal surface of the housing to enable entry of air from the vicinity of the intersection to establish relatively slow, laminar air flow through the chamber, thereby to enable an effective ion current to be maintained within the chamber despite high velocity of oncoming air.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.