Simplex Time Recorder Co.

Charles B Winterble

Lawrence G Stanley

Wayne A Nelson

Timothy C Repp

Rony R Seyouri

A fire detection system cross correlates the responses of a temperature and smoke sensing units to achieve early-detection characteristics. The system also performs threshold-type detection on the smoke obscuration, temperature, and rate of temperature rise. If any of the thresholds are surpassed, the same alarm condition will be set. As a result, the detection characteristics of the resulting detector can be no worse than the conventional threshold-only systems. The system advantageously, however, provides for the early detection of fires that satisfy the cross correlation characteristics. Thus, it achieves the best performance characteristics of both approaches.

Early fire detection using temperature and smoke sensing

A smoke detection unit has a detection chamber for sampling smoke from a surrounding environment. The detection chamber allows air circulation but is optically opaque. This configuration is typical of photoelectric smoke detectors, for example. A housing defines a window though which air from the environment circulates into and out of the detection chamber. The window's height is approximately the same as the chamber. A cage vane is positioned in the window and is configured as an inverted frustoconical member. An inner edge of the cage vane is spaced away from the chamber. The angled vane, along the other aspects of the unit's configuration, improves sensitivity by increasing smoke circulation through the chamber. This configuration guides the air currents typically created by fires at the ceiling so that the smoke flows easily into the detection chamber.

Smoke detector housing for improved smoke collection

Smoke detector

Grille for a smoke detector

Heat detector

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Princeton, MA, United States of America

Charles B Winterble