Flame imaging system

US5726632A · kind A · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventors

• Heidi Barnes · Forestville, US
• Harvey S. Smith · Engelenbeemden, US

Key dates

• Filing date: Mar 13, 1996
• Grant date: Mar 10, 1998
• Expiry date: Mar 13, 2016

Classification

• Technology area (CPC G): Physics
• CPC primary: G08B17/125
• WIPO field: Control
• WIPO sector: Instruments

Abstract

A system for imaging a flame and the background scene. The flame imaging system consists of two charge-coupled-device (CCD) cameras. One camera uses a 800 nm long pass filter which during overcast conditions blocks sufficient background light so the hydrogen flame is brighter than the background light, and the second CCD camera uses a 1100 nm long pass filter, which blocks the solar background in full sunshine conditions such that the hydrogen flame is brighter than the solar background. Two electronic viewfinders convert the signal from the cameras into a visible image. The operator can select the appropriate filtered camera to use depending on the current light conditions. In addition, a narrow band pass filtered InGaAs sensor at 1360 nm triggers an audible alarm and a flashing LED if the sensor detects a flame, providing additional flame detection so the operator does not overlook a small flame.