Combustion system with a grid switching electrode

Patent metadata

Field	Value
Publication number	US-10627106-B2
Application number	US-201816046165-A
Country	US
Kind code	B2
Filing date	Jul 26, 2018
Priority date	Dec 26, 2012
Publication date	Apr 21, 2020
Grant date	Apr 21, 2020

Abstract

A high voltage can be applied to a combustion reaction to enhance or otherwise control the combustion reaction. The high voltage is switched on or off by a grid electrode interposed between a high voltage electrode assembly and the combustion reaction.

First claim

What is claimed is:

1. A combustion system configured to apply electrical energy to a combustion reaction, comprising:
a flame holder disposed in a combustion volume defined at least partially by a combustion volume wall, and configured to hold a combustion reaction;
a power supply including a first output node configured to carry a first voltage;
a first electrode assembly including a first electrode operatively coupled to the first output node of the power supply and configured to carry the first voltage;
a grid electrode disposed between the first electrode assembly and the flame holder; and
an electrical switch operatively coupled to the grid electrode, the electrical switch being configured to selectably couple and decouple the grid electrode to a shield voltage;
wherein the shield voltage is selected to prevent the combustion reaction from receiving electrical energy from the first electrode assembly.

2. The combustion system configured to apply electrical energy to a combustion reaction of claim 1 , wherein the shield voltage is different than the first voltage.

3. The combustion system configured to apply electrical energy to a combustion reaction of claim 2 , wherein the shield voltage is voltage ground.

4. The combustion system configured to apply electrical energy to a combustion reaction of claim 1 , wherein the first electrode assembly includes the first electrode and a counter electrode;
wherein the first electrode and counter electrode are operatively coupled to respective first and second nodes of the power supply; and
wherein the power supply is configured to output respective voltages on the first and second nodes selected to cause an ionic wind to stream from the first electrode toward the grid electrode.

5. The combustion system configured to apply electrical energy to a combustion reaction of claim 1 , wherein the first electrode assembly includes the first electrode and a counter electrode; and
wherein the first electrode is a corona electrode.

6. The combustion system configured to apply electrical energy to a combustion reaction of claim 5 , wherein the power supply is configured to output a voltage on the first node operatively coupled to the first electrode at or above a corona inception voltage.

7. The combustion system configured to apply electrical energy to a combustion reaction of claim 1 , wherein the electrical switch is further configured to selectively decouple the grid electrode from the shield voltage.

8. The combustion system configured to apply electrical energy to a combustion reaction of claim 7 , wherein the power supply is configured to drive a grid electrode electrical node to cause the first electrode assembly to raise the grid electrode to an equilibrium electrical potential substantially equal to a local voltage corresponding to an electric field formed between the first electrode assembly and the combustion reaction when the grid electrode is decoupled from the shield voltage.

9. The combustion system configured to apply electrical energy to a combustion reaction of claim 7 , wherein the grid electrode is configured to electrically float when the grid electrode is decoupled from the shield voltage.

10. The combustion system configured to apply electrical energy to a combustion reaction of claim 1 , wherein the electrical switch is further configured to selectively decouple the grid electrode from the shield voltage and couple the grid electrode to a passing voltage node of the power supply configured to carry a passing voltage selected to allow the first electrode assembly to apply electrical energy to the combustion reaction.

11. The combustion system configured to apply electrical energy to a combustion reaction of claim 10 , wherein the power supply is configured to output a variable passing voltage on the passing voltage node, the variable passing voltage being selected to cause the first electrode assembly to apply electrical energy to the combustion reaction proportional to the variable passing voltage.

12. The combustion system configured to apply electrical energy to a combustion reaction of claim 1 , wherein the electrical switch comprises an insulated gate bipolar transistor (IGBT).

13. The combustion system configured to apply electrical energy to a combustion reaction of claim 1 , wherein the electrical switch is part of the power supply.

14. The combustion system configured to apply electrical energy to a combustion reaction of claim 1 , further comprising a controller configured to control the electrical switch.

15. The combustion system configured to apply electrical energy to a combustion reaction of claim 14 , wherein the controller is part of the power supply.

16. The combustion system configured to apply electrical energy to a combustion reaction of claim 14 , wherein the controller is separate from the power supply.

17. The combustion system configured to apply electrical energy to a combustion reaction of claim 14 , wherein the controller is configured to control the electrical switch to cause the first electrode assembly to apply electrical energy to the combustion reaction corresponding to an electric field waveform having fast rising edges.

18. The combustion system configured to apply electrical energy to a combustion reaction of claim 14 , wherein the controller is configured to control the electrical switch to cause the first electrode assembly to apply electrical energy to the combustion reaction corresponding to an electric field waveform having fast falling edges.

19. The combustion system configured to apply electrical energy to a combustion reaction of claim 14 , wherein the controller is configured to control the electrical switch to cause the first electrode assembly to apply electrical charges to the combustion reaction according to a waveform having fast rising edges.

20. The combustion system configured to apply electrical energy to a combustion reaction of claim 14 , wherein the controller is configured to control the electrical switch to cause the first electrode assembly to apply electrical charges to the combustion reaction corresponding to a waveform having fast falling edges.

21. The combustion system configured to apply electrical energy to a combustion reaction of claim 1 , wherein the grid electrode comprises a cylindrical surface.

22. The combustion system configured to apply electrical energy to a combustion reaction of claim 1 , wherein the grid electrode comprises a metal screen.

23. The combustion system configured to apply electrical energy to a combustion reaction of claim 1 , wherein the grid electrode comprises a metal screen having a mesh size of about 6 millimeters square.

24. The combustion system configured to apply electrical energy to a combustion reaction of claim 1 , wherein the grid electrode comprises stainless steel hardware cloth.

Assignees

• Clearsign Comb Corp
• Clearsign Tech Corporation

Inventors

• Krichtafovitch Igor A
• Wiklof Christopher A

Classifications

• F23N5/00

  Systems for controlling combustion (regulating fuel supply F23N1/00, regulating air supply or draught F23N3/00) · CPC title

• F23C99/001 Primary

  Applying electric means or magnetism to combustion (for combustion engines F02B51/04, F02M27/04) · CPC title

• F23N5/123

  using electronic means · CPC title

• F23N2223/30

  Switches · CPC title