Lyman Lee Blackwell
Engineers at Willow Gln Ct, Boulder, CO

4012729, Mar 15, 1977

Jun 19, 1975

5/588153

Stephen Weaver - Lakewood CO
Lyman L. Blackwell - Boulder CO
Paul A. Staby - Denver CO

Statitrol Corporation - Lakewood CO

G08B 1710

340237S

A fire alarm system utilizes an ionization type aerosol detector having first and second intercommunicating and electrically in series ionization regions or chambers irradiated by a particle source. Electrodes are provided which operate in conjunction with a DC voltage source to establish a relatively large voltage gradient across the first region and a relatively small voltage gradient in the second region. Also, the location of the ion source and the effective volumes of the regions are arranged to establish a comparatively high ion density in the first region. In operation, the impedance or resistance of the first region to ion current flow is substantially uninfluenced by the presence of combustion or smoke aerosols due to the relatively high field gradient while the impedance or resistance of the second region is measurably changed thereby. The insensitivity of the first region to the presence of smoke is due to the high voltage gradient therein, as well as to the high ion density therein. The detector operates by the method of employing the second region as a signal or sensing ion chamber and the first region as a reference chamber, thereby to develop electrical signals on the electrodes representative of detected smoke aerosols for driving the associated fire alarm circuitry.

4093886, Jun 6, 1978

Jul 6, 1976

5/702909

Lyman L. Blackwell - Boulder CO

Statitrol Corporation - Lakewood CO

H01J 740

313 54

Fire alarm system utilizing an aerosol detector of the type formed by outer and inner interconnected ion chambers with a single particle source located within the inner chamber. The particle source radiates charged particles emitted therefrom into the inner chamber as well as through the path of chamber interconnection into the outer ion chamber. The outer chamber communicates directly with atmosphere to be monitored and operates as a sensing ion chamber. The inner chamber, operates as a reference ion chamber, is only interconnected with the outer chamber, and is otherwise totally isolated from outside atmosphere to avoid contamination of the particle source therein. Two embodiments of aerosol detector are disclosed. The first has a radiation permeable, aerosol impermeable dielectric film, made of a material such as Mylar, Teflon or the like, mounted as a barrier across the path of chamber interconnections to permit charged particles emitted from the particle source to pass essentially uninfluenced therethrough while isolating the inner chamber from smoke and combustion aerosols to prevent contamination of the particle source. The dielectric film also provides a physical barrier which prevents a detached particle source from falling out of the inner chamber.

RE29983, May 1, 1979

Jun 21, 1976

5/698055

Lyman L. Blackwell - Boulder CO
Paul A. Staby - Lakewood CO

Emerson Electric Co. - St. Louis MO

G08B 1900, G08B 1710

340629

Time pulse generator having biasing means therefor including a control device, which may be a transistor and means interconnecting the biasing means to the battery being monitored. The output of the time pulse generator is utilized to drive a signaling device to indicate a low level of battery energy and/or an alarm condition as detected by an external condition sensor.