FLAME SENSING

• US 20170038251A1
• Filed: 08/05/2015
• Published: 02/09/2017
• Est. Priority Date: 08/05/2015
• Status: Active Grant

• Current Assignee: Baker Hughes Holdings LLC (Baker Hughes Company)
• Original Assignee: General Electric Company
• Inventors: Lambach, Kenneth Keith, Spalding, Michael Charles
• Granted Patent: US 10,126,164 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F23N 2229/06 with periodical shutters; Modulation signals
• CPC Class Codes: F23N 5/082 using electronic means
• CPC Class Codes: G01J 1/0228 Control of working procedures; Failure detection; Spectral bandwidth calculation
• CPC Class Codes: G01J 1/08 Arrangements of light sources specially adapted for photometry standard sources, also using luminescent or radioactive material
• CPC Class Codes: G01J 1/429 applied to measurement of ultraviolet light using counting tubes G01T
• CPC Class Codes: G01J 5/0018 Flames, plasma or welding
• CPC Class Codes: G01J 5/026 Control of working procedures of a pyrometer, other than calibration; Bandwidth calculation; Gain control
• CPC Class Codes: G01J 5/042 High-temperature environment G01J5/0007, G01J5/0044, G01J5/0088 and G01J5/004 take precedence
• CPC Class Codes: G01J 5/0875 Windows; Arrangements for fastening thereof
• CPC Class Codes: G01J 5/0896 using a light source, e.g. for illuminating a surface
• CPC Class Codes: G01N 2021/157 Monitoring by optical means
• CPC Class Codes: G01N 21/94 Investigating contamination, e.g. dust G01N21/85 takes precedence
• CPC Class Codes: G01N 2201/062 LED's
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A flame sensor detects the presence of a flame in a combustion system in which the flame emits light. The flame sensor includes a body connectable with the combustion system. A photodetector is supported in the body. The photodetector responds to light emitted by the flame and generates an electrical signal proportional to an intensity of the light. A window is supported in the body and located between the combustion system and photodetector. The window is susceptible to contamination from the combustion system and the contamination may decrease sensitivity of the photodetector. A light source is supported in the body. The light source emits light so that a predetermined amount of the light emitted by the light source reflects into the photodetector when contamination is present on the window and the photodetector generates a signal indicative of contamination on the window.

Claims

1. A flame sensor for detecting the presence of a flame in a combustion system in which the flame emits electromagnetic radiation, the flame sensor comprising:

a body disposed proximate to the combustion system;

a photodetector supported in the body, the photodetector configured to generate an electrical signal proportional to an intensity of electromagnetic radiation;

a window supported in the body and located between the combustion system and the photodetector; and

a source supported in the body, the source emitting electromagnetic radiation toward the window, wherein at least some of the electromagnetic radiation emitted by the source reflects back toward the photodetector when contamination is present on the window.

2. The flame sensor of claim 1 further including a modulator that modulates the electromagnetic radiation emitted by the source, wherein the photodetector is further configured to distinguish the electromagnetic radiation emitted by the flame from the electromagnetic radiation emitted by the source using the modulation.

3. The flame sensor of claim 2 wherein the modulator is configured to modulate the electromagnetic radiation source by varying the electromagnetic radiation emitted by the source according to a predetermined pattern.

4. The flame sensor of claim 3 further including a processor configured to filter the pattern of the electromagnetic radiation emitted by the source from the electromagnetic radiation emitted by the flame to determine the amount of electromagnetic radiation emitted by the source reflected into the photodetector.

5. The flame sensor of claim 1 wherein the source is configured to emit electromagnetic radiation within a range of wavelengths that the photodetector is capable of detecting.

6. The flame sensor of claim 1 wherein the photodetector is configured to detect the electromagnetic radiation emitted by the flame in an ultraviolet range of wavelengths.

7. The flame sensor of claim 1 further including a moisture sensor configured to indicate the presence of moisture within the combustion system.

8. The flame sensor of claim 1 further including a circuit board configured to support the photodetector and the source.

9. The flame sensor of claim 1 wherein the photodetector is configured to differentiate between electromagnetic radiation emitted by the flame and electromagnetic radiation emitted by the source.

10. A system comprising:

a combustion source in which a flame may be generated and in which the flame emits electromagnetic radiation;

a sensor for detecting the presence of the flame in the combustion source, the flame sensor comprising;

a body disposed proximate to the combustion system;

a photodetector supported in the body, the photodetector configured to generate an electrical signal proportional to an intensity of electromagnetic radiation;

a window supported in the body and located between the combustion system and the photodetector; and

a source supported in the body, the source emitting electromagnetic radiation toward the window, wherein at least some of the electromagnetic radiation emitted by the source reflects back toward the photodetector when contamination is present on the window; and

a modulator to modulate the source by varying the electromagnetic radiation emitted by the source to a predetermined pattern so the electromagnetic radiation sensed by the photodetector can be distinguished between the electromagnetic radiation emitted by the source and the electromagnetic radiation emitted by the flame.

11. The system of claim 10 further including a processor configured to filter the pattern of the electromagnetic radiation emitted by the source from the electromagnetic radiation emitted by the flame to determine the amount of electromagnetic radiation emitted by the source reflected into the photodetector.

12. The system of claim 10 further including a processor configured to determine the amount of electromagnetic radiation emitted by the source reflected into the photodetector at a predetermined time.

13. The system of claim 10 further including a moisture sensor configured to indicate the presence of moisture within the combustion system.

14. The system of claim 10 wherein the photodetector is configured to detect the electromagnetic radiation emitted by the flame in an ultraviolet range of wavelengths.

15. The system of claim 10 further including circuit board configured to support the photodetector and the source.

16. A method of detecting contamination on a flame sensor window, the method comprising the steps of:

providing a flame sensor for detecting the presence of a flame in a combustion system in which the flame emits electromagnetic radiation, the flame sensor including a body disposed proximate to the combustion system;

supporting a photodetector in the body, the photodetector detecting the electromagnetic radiation emitted by the flame, the photodetector configured to generate an electrical signal proportional to an intensity of the electromagnetic radiation;

supporting a window in the body and locating the window between the combustion system and the photodetector;

supporting a source in the body, the source emitting electromagnetic radiation toward the window;

passing a first predetermined amount of the electromagnetic radiation emitted by the source through the window when there is no contamination on the window;

reflecting a second predetermined amount of the electromagnetic radiation emitted by the source in a direction towards the photodetector when there is contamination on the window; and

detecting with the photodetector the second predetermined amount of the electromagnetic radiation emitted by the source and communicating a signal indicative of contamination on the window.

17. The method of claim 16 further including the step of modulating the source by varying the electromagnetic radiation emitted by the source in a predetermined pattern so the electromagnetic radiation sensed by the photodetector can be distinguished between the electromagnetic radiation emitted by the source and the electromagnetic radiation emitted by the flame.

18. The method of claim 16 further including the step of providing a moisture sensor configured to indicate the presence of moisture within the combustion system.

19. The method of claim 16 further including the step of detecting with the photodetector electromagnetic radiation emitted from the flame in the ultraviolet range.

20. The method of claim 16 further including the step of processing the signal to determine the amount of electromagnetic radiation emitted by the source reflected into the photodetector at a predetermined time.