Fuel control system, parts therefor and methods of making and operating the same

• US 5,577,905 A
• Filed: 11/16/1994
• Issued: 11/26/1996
• Est. Priority Date: 11/16/1994
• Status: Expired due to Fees

• Current Assignee: Robertshaw Controls Company (Schneider Electric SE)
• Original Assignee: Robertshaw Controls Company (Schneider Electric SE)
• Inventors: Moore, Dwain F., Momber, Gregory J.
• Primary Examiner(s): Dority, Carroll B.
• Application Number:
  US08/340,527
• Time in Patent Office: 741 Days
• Field of Search: 431/25, 431/66, 431/72, 431/73, 431/74, 431/46, 431/78
• US Class Current: 431/66
• CPC Class Codes: F23N 2223/08 Microprocessor; Microcomputer
• CPC Class Codes: F23N 2225/12 room temperature
• CPC Class Codes: F23N 2227/22 Pilot burners
• CPC Class Codes: F23N 2227/36 Spark ignition, e.g. by means of a high voltage
• CPC Class Codes: F23N 2229/12 with flame rectification current detecting means
• CPC Class Codes: F23N 2235/16 variable flow or proportional valves
• CPC Class Codes: F23N 5/12 using ionisation-sensitive elements, i.e. flame rods
• CPC Class Codes: F23N 5/203 using electronic means

Abstract

A fuel control system, parts therefor and methods of making and operating the same are provided, the fuel control system comprising an ignition unit for igniting fuel issuing from a burner, and a flame detecting unit for detecting flame at the burner, the flame detecting unit comprising a sensing device for receiving an electrical signal caused by flame rectification at the burner, and an output device for cycling the signal to the sensing device in an on and off manner in each cycle of operation of the output device, the control system having a modulating unit for modulating the on time and the off time of the output device in each cycle of operation thereof.

Claims

1. In a fuel control system for a burner means and comprising ignition means for igniting fuel issuing from said burner means, and flame detecting means for detecting flame at said burner means, said flame detecting means comprising a sensing means for receiving an electrical signal means caused by flame rectification at said burner means, and an output means for cycling said signal means to said sensing means in an on and off manner in each cycle of operation of said output means, the improvement wherein said control system has modulating means for modulating the on time and the off time of said output means in each cycle of operation thereof.

2. A fuel control system as set forth in claim 1 wherein said modulating means comprises a microcomputer means.

3. A fuel control system as set forth in claim 2 wherein said output means comprises a driving transistor for cycling said signal means.

4. A fuel control system as set forth in claim 3 wherein said sensing means comprises a field effect transistor having a gate that receives said signal means.

5. A fuel control system as set forth in claim 4 wherein said driving transistor has a collector electrically interconnected to said gate of said field effect transistor and has a gate electrically interconnected to said microcomputer means so as to be modulated thereby.

6. A fuel control system as set forth in claim 2 wherein said microcomputer means is operatively interconnected to said sensing means and has burner control means to maintain a flow of fuel to said burner means as long as said sensing means is detecting flame at said burner means.

7. A fuel control system as set forth in claim 2 wherein said microcomputer means is operatively interconnected to said sensing means and has quantifying means to determine the value of the electrical current of said signal means being sent to said sensing means and thereby determine the size of the flame at said burner means at that time.

8. A fuel control system as set forth in claim 7 wherein said microcomputer means has means to store the determined values of the electrical currents of said signal means for future use of such information.

9. A fuel control system as set forth in claim 1 wherein said ignition means comprises means to cause electrical sparking at said burner means.

10. A fuel control system as set forth in claim 9 wherein said burner means comprises a pilot burner means for a main burner means.

11. In a fuel control device for controlling the operation of a burner means, said device comprising ignition means for igniting fuel issuing from said burner means, and flame detecting means for detecting flame at said burner means, said flame detecting means comprising a sensing means for receiving an electrical signal means caused by flame rectification at said burner means, and an output means for cycling said signal means to said sensing means in an on and off manner in each cycle of operation of said output means, the improvement wherein said control device has modulating means for modulating the on time and the off time of said output means in each cycle of operation thereof.

12. A fuel control device as set forth in claim 11 wherein said modulating means comprises a microcomputer means.

13. A fuel control device as set forth in claim 12 wherein said output means comprises a driving transistor for cycling said signal means.

14. A fuel control device as set forth in claim 13 wherein said sensing means comprises a field effect transistor having a gate that receives said signal means.

15. A fuel control device as set forth in claim 14 wherein said driving transistor has a collector electrically interconnected to said gate of said field effect transistor and has a gate electrically interconnected to said microcomputer means so as to be modulated thereby.

16. A fuel control device as set forth in claim 12 wherein said microcomputer means is operatively interconnected to said sensing means and has burner control means to maintain a flow of fuel to said burner means as long as said sensing means is detecting flame at said burner means.

17. A fuel control device as set forth in claim 12 wherein said microcomputer means is operatively interconnected to said sensing means and has quantifying means to determine the value of the electrical current of said signal means being sent to said sensing means and thereby determine the size of the flame at said burner means at that time.

18. A fuel control device as set forth in claim 17 wherein said microcomputer means has means to store the determined values of the electrical currents of said signal means for future use of such information.

19. In a method of making a fuel control system for a burner means and comprising the steps of providing an ignition means for igniting fuel issuing from said burner means, providing flame detecting means for detecting flame at said burner means, forming said flame detecting means to comprise a sensing means for receiving an electrical signal means caused by flame rectification at said burner means, and forming said flame detecting means to comprise an output means for cycling said signal means to said sensing means in an on and off manner in each cycle of operation of said output means, the improvement comprising the step of forming said control system to have modulating means for modulating the on time and the off time of said output means in each cycle of operation thereof.

20. In a method of making a fuel control device for controlling the operation of a burner means and comprising the steps of providing an ignition means for igniting fuel issuing from said burner means, providing flame detecting means for detecting flame at said burner means, forming said flame detecting means to comprise a sensing means for receiving an electrical signal means caused by flame rectification at said burner means, and forming said flame detecting means to comprise an output means for cycling said signal means to said sensing means in an on and off manner in each cycle of operation of said output means, the improvement comprising the step of forming said control device to have modulating means for modulating the on time and the off time of said output means in each cycle of operation thereof.

21. In a method of operating a fuel control system for a burner means, said system comprising ignition means for igniting fuel issuing from said burner means, and flame detecting means for detecting flame at said burner means, said flame detecting means comprising a sensing means for receiving an electrical signal means caused by flame rectification at said burner means, and an output means for cycling said signal means to said sensing means in an on and off manner in each cycle of operation of said output means, the improvement comprising the step of modulating the on time and the off time of said output means in each cycle of operation thereof.

22. A method as set forth in claim 21 and comprising the step of determining the value of the electrical current of said signal means being sent to said sensing means and thereby determining the size of the flame at said burner means at that time.