Flame Detector

• US 20140312240A1
• Filed: 04/14/2014
• Published: 10/23/2014
• Est. Priority Date: 04/18/2013
• Status: Active Grant

• Current Assignee: Thermo Pro Manufacturing, LLC, Volution Inc.
• Original Assignee: Thermo Pro Manufacturing, LLC, Volution Inc.
• Inventors: Slemon, Charles Shafee, Slemon, Michael Shafee, Slemon, Charles, Morris, Dewey Barton, Walsh, John B.
• Granted Patent: US 9,134,181 B2
• Time in Patent Office: Days
• US Class Current: 250/372
• CPC Class Codes: G01J 1/0252 Constructional arrangements for compensating for fluctuations caused by, e.g. temperature, or using cooling or temperature stabilization of parts of the device; Controlling the atmosphere inside a photometer; Purge systems, cleaning devices protection against electromagnetic interferences G01J2001/0276
• 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 5/0846 having multiple detectors for performing different types of detection, e.g. using radiometry and reflectometry channels
• CPC Class Codes: G08B 17/12 Actuation by presence of radiation or particles, e.g. of infrared radiation or of ions
• CPC Class Codes: G08B 29/183 Single detectors using dual technologies G08B13/1672, G08B13/2448, G08B13/2494 take precedence

Abstract

A system and method are disclosed for detecting open flames in an outdoor environment. Structurally, the outdoor flame detector includes both an ultra-violet (UV) detector and a Radio Frequency (RF) detector. While operating within predetermined parameters, these detectors respectively create an event signal(s) and a cancel signal(s). In detail, the UV detector will output an event signal whenever UV radiation with a fluence above a predetermined value is incident on the UV detector. On the other hand, the RF detector will output a cancel signal whenever it receives an RF component transmitted in an electrical arc discharge having an intensity above a predetermined threshold. The event signal and the cancel signal are then individually and collectively evaluated by a computer to distinguish between an actual open flame and a non-flame event, such as an electric arc discharge (e.g. lightening, electric motors and arc welding).

Claims

1. A flame sensing unit which comprises:

an optical sensor for creating an event signal, wherein the event signal is indicative of a flame and is created whenever ultra-violet (UV) radiation is incident on the sensor and the incident UV radiation exceeds a predetermined fluence;

a hollow, transparent tube having a first end and a second end with a lumen extending therebetween, wherein the lumen of the tube is dimensioned for receiving the optical sensor therein;

a self-regulating heater mounted on the first end of the tube for maintaining the tube at an operational temperature, wherein the operational temperature is in a predetermined temperature range and is established to prevent moisture effects on the tube;

a housing engaged with the first end of the tube and with the second end of the tube to support the sensor in the tube, wherein the housing protectively encloses the tube and is formed with an aperture to allow UV radiation from an external source to pass through the aperture for incidence on the optical sensor in the tube; and

a controller electronically connected with the optical sensor and with the heater, to manage operation of the optical sensor and to maintain the operational temperature of the tube for sensing UV radiation indicative of a flame.

2. A unit as recited in claim 1 further comprising:

an electro-magnetic sensor for creating a cancel signal in response to the reception of a Radio Frequency (RF) component transmitted in an electrical arc discharge;

an antenna electrically connected to the electro-magnetic sensor for receiving the RF component of the electrical arc discharge, wherein the antenna has a predetermined length L, and the length L is established to receive RF components having an intensity above a predetermined threshold; and

a controller electronically connected to the electro-magnetic sensor for monitoring an operation of the electro-magnetic sensor for creation of the cancel signal.

3. A unit as recited in claim 2 further comprising:

a computer connected to the controller of the optical sensor for receiving the event signal therefrom, and connected to the controller of the electro-magnetic sensor for receiving the cancel signal therefrom, and for stopping the event signal when the event signal and a cancel signal are received simultaneously by the computer; and

an alarm connected to the computer for indicating the presence of a flame when the alarm receives an event signal.

4. A unit as recited in claim 3 further comprising a faraday cage for surrounding the electro-magnetic sensor.

5. A unit as recited in claim 3 wherein the electro-magnetic sensor is an amplitude modulated radio receiver.

6. A unit as recited in claim 3 wherein the RF component of the electrical arc discharge is in an approximate range between 200 kHz and 2 MHz.

7. A unit as recited in claim 3 further comprising an optical magnifier positioned relative to the optical sensor to increase the fluence of the UV radiation incident on the optical sensor.

8. A unit as recited in claim 3 wherein the controller of the optical sensor includes a DC to DC multiplier for providing the optical sensor with an activation voltage of approximately 400 volts.

9. A unit as recited in claim 3 wherein the tube has an outer surface area and the housing establishes a stand-off gap between the housing and a majority of the outer surface area of the tube.

10. A unit as recited in claim 3 wherein the optical sensor has a Field of View (FOV) within a horizontal arc of approximately one hundred ten degrees (110°

).

11. A unit as recited in claim 10 further comprising a means for rotating the optical sensor through an arc of φ

degrees to scan the FOV through an arc of (110+φ

)°

.

12. A system for sensing flames which comprises:

an ultra-violet (UV) detector for creating an event signal, wherein the event signal is indicative of a flame and is created whenever ultra-violet (UV) radiation is incident on the detector, and the incident UV radiation exceeds a predetermined fluence;

a Radio Frequency (RF) detector for creating a cancel signal in response to the reception of a Radio Frequency (RF) component transmitted in an electrical arc discharge;

a computer connected to the controller of the optical sensor for receiving the event signal therefrom, and connected to the controller of the electro-magnetic sensor for receiving the cancel signal therefrom, and for stopping the event signal when the event signal and a cancel signal are received simultaneously by the computer; and

an alarm connected to the computer for indicating the presence of a flame when the alarm receives an event signal.

13. A system as recited in claim 12 wherein the UV detector comprises:

an optical sensor;

a hollow, transparent tube having a first end and a second end with a lumen extending therebetween, wherein the lumen of the tube is dimensioned for receiving the sensor therein;

a self-regulating heater mounted on the first end of the tube for maintaining the tube at an operational temperature, wherein the operational temperature is in a predetermined temperature range and is established to prevent moisture effects on the tube;

a housing engaged with the first end of the tube and with the second end of the tube to support the sensor in the tube, wherein the housing protectively encloses the tube and is formed with an aperture to allow UV radiation from an external source to pass through the aperture for incidence on the optical sensor in the tube; and

a controller electronically connected with the optical sensor and with the heater to manage operation of the optical sensor and to maintain the operational temperature of the tube for sensing UV radiation indicative of a flame.

14. A system as recited in claim 13 wherein the optical sensor has a Field of View (FOV) within a horizontal arc of approximately one hundred ten degrees (110°

).

15. A system as recited in claim 12 wherein the RF detector comprises:

an electro-magnetic sensor;

an antenna electrically connected to the electro-magnetic sensor for receiving the RF component of the electrical arc discharge, wherein the antenna has a predetermined length L, and the length L is established to receive RF components having an intensity above a predetermined threshold; and

a controller electronically connected to the electro-magnetic sensor for monitoring an operation of the electro-magnetic sensor for creation of the cancel signal.

16. A system as recited in claim 15 wherein the electro-magnetic sensor is an amplitude modulated radio receiver surrounded by a faraday cage, and wherein the RF component of the electrical arc discharge is in an approximate range between 200 kHz and 2 MHz.

17. A system as recited in claim 12 wherein the system is positioned with at least one other system to create an array of systems for monitoring a target area.

18. A system as recited in claim 12 further comprising an optical magnifier positioned relative to the UV detector to increase the fluence of the UV radiation incident on the UV detector.

19. A method for sensing flames which comprises the steps of:

creating an event signal using an ultra-violet detector having an optical sensor, wherein the event signal is indicative of a flame and is created whenever ultra-violet (UV) radiation is incident on the optical sensor, and the incident UV radiation exceeds a predetermined fluence;

creating a cancel signal using a Radio Frequency (RF) detector having an electro-magnetic sensor, wherein the cancel signal is created in response to the reception by the electro-magnetic sensor of a Radio Frequency (RF) component transmitted in an electrical arc discharge;

using a computer for receiving the event signal and for receiving the cancel signal;

stopping the event signal when an event signal and a cancel signal are received simultaneously by the computer; and

providing an alarm for indicating the presence of a flame when the alarm receives an event signal.

20. A method as recited in claim 19 further comprising the step of protecting the ultra-violet detector with a unit comprising:

a hollow transparent tube having a first end and a second end with a lumen extending therebetween, wherein the lumen of the tube is dimensioned for receiving the optical sensor therein;

a self-regulating heater mounted on the first end of the tube for maintaining the tube at an operational temperature, wherein the operational temperature is in a predetermined temperature range and is established to prevent moisture effects on the tube; and

a housing engaged with the first end of the tube and with the second end of the tube to support the optical sensor in the tube, wherein the housing protectively encloses the tube and is formed with an aperture to allow UV radiation from an external source to pass through the aperture for incidence on the optical sensor in the tube.