FLAME DETECTOR

• US 3,635,018 A
• Filed: 12/31/1969
• Issued: 01/18/1972
• Est. Priority Date: 12/31/1969
• Status: Expired due to Term

• Current Assignee: Mitchell I. Meyer, Serafino M De Corso
• Original Assignee: Mitchell I. Meyer, Serafino M De Corso
• Inventors: De Corso, Serafino M., Meyer, Mitchell I.
• Primary Examiner(s): Hart, Douglas
• Application Number:
  US04/889,413
• Time in Patent Office: 748 Days
• Field of Search: 60/39.09 431/13,14,15,75,78 73/35,116,346,DIG.4 340/227,228F 179/1.41B
• US Class Current: 60/39.091
• CPC Class Codes: F02C 7/262 Restarting after flame-out
• CPC Class Codes: Y10S 73/04 Piezoelectric

Abstract

Apparatus for detecting the existence of a flame in a combustion chamber by means including an electroacoustic device for converting audible sounds which occur only when the flame is present into an electrical signal having a frequency component corresponding to the frequency of the audible sound. If necessary, a filter may be incorporated into the converting means for eliminating frequencies which occur due to the introduction of fuel and/or a gas containing oxygen into the combustion chamber without the existence of a flame. Alternatively, a threshold detector can be incorporated into the system for detecting audible sounds above a predetermined sound level only, which sounds are those due to the existence of a flame.

Claims

1. An apparatus for detecting the existence of a flame in a combustion chamber for a gas turbine power plant of the type having a combustion chamber connected through a transition member to an outlet which directs the products of combustion against the blades of said turbine, the combination of an electroacoustic device for converting sound energy into an electrical signal having a frequency component equal to the frequency of the sound converted, said frequency of sound being between 1,000 cycles per second and 20,000 cycles per second, a passageway having one end opening into said combustion chamber and another end in soundtransmitting relationship with said electroacoustic device, indicating circuit means connected to said electroacoustic device for indicating the existence of sound waves in said combustion chamber which occur when a flame exists in the combustion chamber, rejection filter means interposed between said electroacoustic device and said indicating circuit means for filtering out the frequencies of noises due to effects other than the existence of a flame, said rejection filter means operable between the frequencies of 6,000 cycles per second and 16,000 cycles per second.

2. The apparatus of claim 1 and further including a threshold detector interposed between said electroacoustic device and said indicating circuit means for eliminating signals other than those above a predetermined noise level.

3. The apparatus of claim 1 wherein said electroacoustic device comprises a piezoelectric crystal.

4. The apparatus of claim 1 wherein said electroacoustic device comprises a microphone.