WO1998033016B1

WO1998033016B1 - High turndown modulating gas burner

Info

Publication number: WO1998033016B1
Application number: PCT/US1998/000439
Authority: WO
Filing date: 1998-01-07
Publication date: 1998-10-01

Abstract

A gas burner (10) and method of controlling burning, the gas burner (10) including a controller disposed in a control cabinet (10), a burner cabinet (14), an actuator (16) and a blower (18), the blower (18) being fuidly coupled to the burner cabinet (14). The gas burner (10) has an air valve (40) that is operably, fluidly coupled to both the burner cabinet (14) and the blower (18) for controlling the flow of air from the blower (18) to the burner cabinet (14). A gas valve (36) is fluidly coupled to a source of gas for controlling the flow of gas from the source of gas. An actuator (16) is communicatively coupled to the controller and is linearly coupled to the air valve (40) and the gas valve (36) for simultaneously linear actuation thereof responsive to commands from the controller.

Claims

27AMENDED CLAIMS[received by the International Bureau on 21 August 1998 (21.08.98); original claims 1 and 20 amended; remaining claims unchanged (7 pages)]

1. A gas burner having a controller disposed in a control cabinet, a burner cabinet, an actuator and a blower, the blower being fluidly coupled to the burner cabinet, comprising: air valve means being operably, fluidly coupled to both the burner cabinet and the blower for controlling the flow of aprimary air, a secondary air, and a base air from the blower to the burner cabinet; gas valve means fluidly coupled to a source of gas for controlling the flow of gas from said source of gas; and actuation means communicatively coupled to the controller and being linearly coupled to the air valve means and the gas valve means for simultaneous linear actuation thereof responsive to commands from the controller.

2. The gas burner of claim 1 further including at least one interlock switch being disposed within the control cabinet and being communicatively coupled to the controller, this at least one interlock switch being made and unmade by linear actuation of the actuator means.

3. The gas burner of claim 2 wherein the actuator means includes a first arm having a longitudinal axis, axial translation of the first arm acting to actuate the air valve means, the gas valve means and the at least one interlock switch.

4. The gas burner of claim 3, the actuator means further including a second arm having a longitudinal axis operably coupled to the first arm in a substantially transverse disposition, a rotatable arm having a bearing disposed thereon, the bearing being in slidable engagement with the second arm whereby rotation of the rotatable arm causes the bearing to axially translate on the second arm, thereby imparting axial linear translation of the first arm. 28

5. A gas valve for use with a gas burner, comprising: an orifice disposed in a gas flow passageway; and a linearly translatable plug disposed in the orifice being translatable within the orifice along a translation axis, having a tapered dimension extending along the translation axis, whereby linear translation of the plug along the translation axis acts to vary the area of the orifice available for the passage of gas therethrough.

6. The gas valve of claim 5 wherein the plug has a compound taper of the tapered dimension.

7. The gas valve of claim 5 wherein the amount of taper of the tapered dimension is varied responsive to the need for a selected gas flow.

8. The gas valve of claim 5 wherein the orifice is generally rectangular in shape and the plug has a generally rectangular cross-section taken transverse to the translation axis thereof.

9. The gas burner of claim 5 further including: a housing having a longitudinal axis and being fluidly coupled at a gas inlet to a source of gas, and having the gas passageway defined therein; an orifice plate having the orifice defined therein and being disposed in the gas passageway of the housing, between the gas inlet and the fluid outlet; a fluid inlet fluidly coupled to the gas passageway between the orifice plate and the fluid outlet, the fluid inlet being coupled to a source of fluid for introducing the fluid to the air passageway and mixing the gas flowing therein.

SHEET ARTICLE 19 29

10. The gas burner of claim 9 wherein the translation axis of the translatable plug being disposed generally parallel to the housing longitudinal axis, and further including a bearing being disposed in the housing and slidably supporting an actuator, the actuator being operably coupled to the translatable plug.

11. A burner gun for use with a gas burner, comprising: a nozzle having a fluid inlet and a plurality of fluid outlets; and base air delivery means having an air inlet and a plurality of air outlets, each one with said plurality of air outlets being disposed in a cooperative relationship with a corresponding one of said plurality of nozzle fluid outlets whereby a flow of air discharged from each of said plurality of air outlets mixes with a flow of fluid discharged from the corresponding one of said plurality of nozzle fluid outlets.

12. The burner gun of claim 11 wherein the nozzle is generally tubular having a longitudinal axis, having a first end fluidly coupled to a source of fluid and the plurality of nozzle outlets being disposed proximate a nozzle second end, the nozzle outlets being disposed radially with respect to the nozzle longitudinal axis.

13. The burner gun of claim 12 further including a shroud disposed concentric with the nozzle and spaced apart from the nozzle to define a base air passageway between the shroud and the nozzle, the base air passageway being fluidly coupled to the plurality of air outlets.

14. The burner gun of claim 13 further including an air inlet defined in the shroud and fluidly coupled to the base air passageway. 30

15. An air valve for use with a gas burner, comprising: a profile plate having at least one secondary air aperture defined therein and a primary air aperture defined therein; and a linearly slidable plate disposed with respect to the profile plate such that linear translation thereof acts to vary the area of the primary and secondary air apertures.

16. The air valve of claim 15 being linearly translatable between a minimum fire position and a maximum fire position, the slidable plate substantially closing off the at least one secondary air aperture in the minimum fire position and fully opening the second air aperture in the maximum fire position, the slidable plate partially opening the primary air aperture in the minimum fire position and closing the primary air aperture at a selected position of translation between the minimum fire position and the maximum fire position.

17. The air valve of claim 15 further including a base air aperture and a secondary air bore.

18. The air valve of claim 16 further including a characterized secondary air aperture being shaped to supplement the at least one secondary air aperture for a specific application of the gas burner.

19. The air valve of claim 15 further including a restrictor plate variable positionable with respect to the at least one secondary air aperture to selectively vary the area of the at least one secondary air aperture.

20. An actuator for use with a gas burner, the gas burner having a controller, a gas valve, and an air valve, comprising: a motor, being operably, communicatively coupled to the controller; 31

a linear actuator arm operably coupled to the motor and being operably coupled to the gas valve and to the air valve, whereby linear translation of the linear actuator arm imparts linear actuation to both the gas valve and the air valve, the air valve controlling delivery of a primary air, a secondary air and a base air to the burner.

21. The actuator of claim 20 wherein the linear actuator arm has a stroke of a selected length, the stroke defining a minimum fire position at a first end of the stroke and defining a maximum fire position at a second end of the stroke.

22. The actuator of claim 21 wherein the length of the stroke of the linear actuator arm is substantially equal to a stroke of the gas valve between a gas valve minimum fire position and a gas valve maximum fire position and the length of the stroke of the linear actuator arm is substantially equal to a stroke of the air valve of the air valve between an air valve minimum fire position and an air valve maximum fire position.

23. The actuator as claimed in claim 21, the controller having a minimum fire interlock switch and a maximum fire interlock switch, further including actuation means fixedly coupled to the linear actuation arm, the actuation means making the minimum fire switch when the linear actuation arm is at the minimum fire position and the actuation means making the maximum fire switch when the actuation arm is in the maximum fire position.

24. The actuator as claimed in claim 20, further including: a rotatable actuator arm being rotatably coupled to the motor; 32 a slidable bearing being operably, rotatably coupled to the rotatable actuator arm and having an actuator bore defined therein; and a transverse actuator arm fixedly coupled to the linear actuator arm and disposed substantially transverse thereto, the transverse actuator arm being slidably disposed within the slidable reading actuator bore.

25. The actuator as claimed in claim 20 further including a sleeve, selectively positioned on the linear actuator arm, having an air control arm operably coupled to the air valve and a gas control arm operably coupled to the gas valve, the air control arm and the gas control arm simultaneously imparting linear actuation to the respective air valve and gas valve responsive to translational motion of the linear actuator arm.

26. A method of controlling a gas burner, the gas burner including an air valve being fluidly coupled to a source of air, a gas valve being fluidly coupled to a source of gas, a burner gun being fluidly coupled to both the air valve and the gas valve, and a plurality of interlock switches, comprising the step of; simultaneously providing linear actuation to the air valve, the gas valve, and the plurality of interlock switches for operation between a minimum fire position and a maximum fire position.

27. The method of claim 26 including the additional step of providing a flow of base air from the air valve to an air passageway defined in the burner gun. 33

28. The method of claim 26 including the additional step of providing a flow of primary air from the air valve to a fluid passageway defined in the gas valve.

29. The method of claim 28 including the additional steps of providing a flow of primary air at a selected flow volume when in the minimum fire position, increasing said flow rate to a selected maximum flow rate at a selected actuation position between the minimum fire position and the maximum fire position, and ceasing said flow rate at a further selected actuation position that is substantially less than the maximum fire position.