The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 11, 1989
Filed:
Mar. 01, 1988
Robert A Dunbar, Swampscott, MA (US);
Pyrotector, Inc., Marshfield, MA (US);
Abstract
A system for detecting a flame or droplets of burning polypropylene in an area below an upper surface of a conventional wet bench used in semiconductor production includes at least one sensor, a threshold detector, a discrimination, a counter and a latch. The sensor detects radiation generated by activity in the area and for generating a sensor signal in response to the detected radiation. The threshold detector determines whether the activity has a cross-sectional area which exceeds a predetermined threshold area. The discriminator determines whether the activity displays a flicker rate or a droplet rate that is within the predetermined flicker rate range. The counter determines whether a predetermined number of flickers or droplets has been detected within a predetermined time period, and the latch asserts a true output signal when the detected activity exceeds the predetermined threshold area, the flicker rate or the droplet rate is within the predetermined flicker rate range, and a predetermined number of flickers or droplets have been detected within the predetermined time period.