Flame detector based on real-time high-order statistics

• US 6,261,086 B1
• Filed: 05/05/2000
• Issued: 07/17/2001
• Est. Priority Date: 05/05/2000
• Status: Expired due to Fees

• Current Assignee: Forney Corporation (Graham Holdings Company)
• Original Assignee: Forney Corporation (Graham Holdings Company)
• Inventors: Fu, Zhizhen
• Primary Examiner(s): Lateef, Marvin M.
• Assistant Examiner(s): Cocks, Josiah C.
• Application Number:
  US09/565,484
• Time in Patent Office: 438 Days
• Field of Search: 431/79, 431/14, 431/75, 431/78, 431/77, 342/90, 342/22, 340/578, 340/577, 340/579, 250/554
• US Class Current: 431/79
• CPC Class Codes: F23N 2223/08 Microprocessor; Microcomputer
• CPC Class Codes: F23N 2223/10 Correlation
• CPC Class Codes: F23N 2223/48 Learning / Adaptive control
• CPC Class Codes: F23N 5/082 using electronic means

Abstract

A method, and a system for implementing the method, for detecting whether a flame is an on state or alternatively is in an off state. The method includes (i) detecting the flame and generating therefrom a flame signal capturing one or more attributes of the flame; (ii) using a high-order cumulant-to-moment formula to determine high-order cumulants for a random variable process representation of the flame signal; and (iii) determining whether the flame is on or off using the high-order cumulants. The method includes the step of applying the high-order cumulant-to-moment formula in a self-learning algorithm to determine flame-on high-order cumulants and flame-off high-order cumulants for the flame. Step (iii) includes comparing the high-order cumulants to the flame-on high-order cumulants and the flame-off high-order cumulants to determine whether the status of the flame is on or off.

Claims

1. A method for detecting whether a flame is an on state or alternatively is in an off state, comprising:

(i) detecting the flame and generating therefrom a flame signal capturing one or more attributes of the flame;

(ii) using a high-order cumulant-to-moment formula to determine one or more high-order cumulants for a random variable process representation of the flame signal; and

(iii) determining whether the flame is on or off using said one or more high-order cumulants.

2. The method according to claim 1, further comprising:

applying said high-order cumulant-to-moment formula in a self-learning algorithm to determine one or more flame-on high-order cumulants and one or more flame-off high-order cumulants for the flame.

3. The method according to claim 2, comprising:

detecting a second flame signal, wherein an on or off status of a flame from which said second flame signal is obtained is known;

converting said second flame from an analog form flame signal to a digitized form flame signal; and

determining said one or more flame-on high-order cumulants and said one or more flame-off high-order cumulants from said digitized form flame signal.

4. The method according to claim 2, wherein step (i) comprises:

detecting said flame signal wherein an on or off status of the flame is unknown; and

converting said flame signal from an analog form flame signal to a digitized form flame signal.

5. The method according to claim 4, wherein detecting of said flame signal comprises:

optically detecting wavelengths of radiation emitted by the flame.

6. The method according to claim 4, wherein step (ii) comprises calculating said high-order cumulants from said digitized form flame signal.

7. The method according to claim 2, wherein step (iii) comprises:

comparing said one or more high-order cumulants to said flame-on high-order cumulants and said flame-off high-order cumulants to determine whether the status of the flame is on or off.

8. The method according to claim 7, wherein step (iii) comprises:

determining one or more threshold cumulants located between said flame-on high-order cumulants and said flame-off high-order cumulants; and

comparing said one or more high-order cumulants to said one or more threshold cumulants to determine whether the status of the flame is on or off.

9. The method according to claim 1, wherein said cumulant-to-moment formula comprises the equation:

$c<br><br>\left(x_1,\mathrm{\dots <br><br>}<br><br>\text{\hspace{1em}<br><br>},x_K\right)=\underset{p}{\sum <br><br>}<br><br>{\left(-1\right)}^{n_p-1}<br><br>\left(n_p-1\right)!<br><br>E<br><br>\left\{\underset{{\mathrm{ieg}}_i^p}{\prod <br><br>}<br><br>X_i\right\}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\dots <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>E<br><br>\left\{\underset{{\mathrm{ieg}}_{n_p}^p}{\prod <br><br>}<br><br>X_i\right\}$

wherein c(x₁, . . . , x_k) represents cumulants,

wherein (x₁, . . . , x_k) represent k discrete random variables of a digitized random process (vector),

wherein p represents partitions,

wherein n_p represents the number of groups in the specific partition,

wherein E{ } represents an expectation,

wherein i represents an integer,

wherein X_i represents an ith random process,

wherein g represents a group in one specific partition,

wherein g_i^p through g_n^p represent the ith through the n_pth partition groups.

10. The method according to claim 1, wherein the flame arises from combustion of a fuel in a burner associated with a boiler, and wherein said fuel comprises any one of:

oil fuel;

gas fuel; and

coal fuel.

11. A system for detecting whether a flame is an on state or alternatively is in an off state, comprising:

device that detects the flame and generates therefrom a flame signal capturing one or more attributes of the flame;

device that uses a high-order cumulant-to-moment formula to determine one or more high-order cumulants for a random variable process representation of the flame signal; and

device that determines whether the flame is on or off using said one or more high-order cumulants.

12. The system according to claim 11, further comprising:

device that applies said high-order cumulant-to-moment formula in a self-learning algorithm to determine one or more flame-on high-order cumulants and one or more flame-off high-order cumulants for the flame.

13. The system according to claim 12, comprising:

device that detects a second flame signal, wherein an on or off status of a flame from which said second flame signal is obtained is known;

device that converts said second flame from an analog form flame signal to a digitized form flame signal; and

device that determines said one or more flame-on high-order cumulants and said one or more flame-off high-order cumulants from said digitized form flame signal.

14. The system according to claim 12, wherein said device that detects the flame and generates therefrom a flame signal capturing one or more attributes of the flame comprises:

device that detects said flame signal wherein an on or off status of the flame is unknown; and

device that converts said flame signal from an analog form flame signal to a digitized form flame signal.

15. The system according to claim 14, wherein said device that detects said flame signal comprises:

device that optically detects wavelengths of radiation emitted by the flame.

16. The system according to claim 14, wherein said device that uses a high-order cumulant-to-moment formula to determine one or more high-order cumulants for a random variable process representation of the flame signal comprises:

device that calculates said high-order cumulants from said digitized form flame signal.

17. The system according to claim 12, wherein said device that determines said one or more flame-on high-order cumulants and said one or more flame-off high-order cumulants from said digitized form flame signal comprises:

device that compares said one or more high-order cumulants to said flame-on high-order cumulants and said flame-off high-order cumulants to determine whether the status of the flame is on or off.

18. The system according to claim 17, wherein said device that determines said one or more flame-on high-order cumulants and said one or more flame-off high-order cumulants from said digitized form flame signal comprises:

device that determines one or more threshold cumulants located between said flame-on high-order cumulants and said flame-off high-order cumulants; and

device that compares said one or more high-order cumulants to said one or more threshold cumulants to determine whether the status of the flame is on or off.

19. The system according to claim 11, wherein said cumulant-to-moment formula comprises the equation:

$c<br><br>\left(x_1,\mathrm{\dots <br><br>}<br><br>\text{\hspace{1em}<br><br>},x_K\right)=\underset{p}{\sum <br><br>}<br><br>{\left(-1\right)}^{n_p-1}<br><br>\left(n_p-1\right)!<br><br>E<br><br>\left\{\underset{{\mathrm{ieg}}_i^p}{\prod <br><br>}<br><br>X_i\right\}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\dots <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>E<br><br>\left\{\underset{{\mathrm{ieg}}_{n_p}^p}{\prod <br><br>}<br><br>X_i\right\}$

wherein c(x₁, . . . , x_k) represents cumulants,

wherein (x₁, . . . , x_k) represent k discrete random variables of a digitized random process (vector),

wherein p represents partitions,

wherein n_p represents the number of groups in the specific partitions,

wherein E{ } represents an expectation,

wherein i represents an integer,

wherein X_i represents an ith random process,

wherein g represents a group in one specific partition,

wherein g_i^p through g_n^p represent the ith through the n_pth partition groups.

20. The system according to claim 11, wherein the flame arises from combustion of a fuel in a burner associated with a boiler, and wherein said fuel comprises any one of:

oil fuel;

gas fuel; and

coal fuel.