Pre-mix fuel-fired appliance with improved heat exchanger interface

Patent metadata

Field	Value
Publication number	US-10281143-B2
Application number	US-201715406567-A
Country	US
Kind code	B2
Filing date	Jan 13, 2017
Priority date	Jan 13, 2017
Publication date	May 7, 2019
Grant date	May 7, 2019

Abstract

A fuel-fired heating appliance comprises a burner and a first housing adjacent the burner so that an interior of the first housing receives combustion gasses from combustion at the burner. A heat exchanger defines a second housing with an inlet proximate an outlet of the first housing so that the inlet of the second housing receives combustion gasses from the outlet of the first housing, and wherein the first and second housings attach at an interface. A barrier extends within, and across an interface between, the outlet of the first housing and the inlet of the second housing and defines a thermal resistance that inhibits heat transfer from the combustion gasses to the interface.

First claim

What is claimed is:

1. A fuel-fired heating appliance comprising:
a combustion chamber that defines an inner cavity and comprising an inlet end and an outlet end;
a burner;
a refractory comprising an inlet face that defines an inlet through aperture and an outlet face, the outlet face of the refractory comprising a counterbore recess that extends inward from the outlet face and defines a periphery of an outlet through aperture;
wherein the burner and the refractory are disposed in the inner cavity of the combustion chamber such that a portion of the burner is disposed between the inlet face of the refractory and the inlet end of the combustion chamber;

a mounting bracket that is coupled to the outlet end of the combustion chamber to securely retain the refractory within the combustion chamber, the refractory defining a first housing adjacent the burner, the first housing configured to receive combustion gases from combustion at the burner;
a heat exchanger tube defining a second housing with an inlet disposed in the counterbore recess of the refractory and proximate the outlet face of the refractory of the first housing so that the inlet of the heat exchanger tube receives the combustion gases from the outlet through aperture of the refractory of the first housing, wherein heat from the combustion gases is conducted through the heat exchanger tube and wherein the heat exchanger tube is configured to transfer heat to air that is blown across an exterior of the heat exchanger tube to condition a space served by the fuel-fired heating appliance; and
a barrier that is configured to inhibit heat transfer from the combustion gases to an interface between the mounting bracket and the heat exchanger tube at the outlet of the combustion chamber,
wherein a portion of the barrier is disposed in the counterbore recess of the refractory such that the portion of the barrier is disposed between the inlet of the heat exchanger tube and the outlet face of the refractory while a remainder portion of the barrier extends towards and into an interior of the heat exchanger tube such that the barrier is disposed between the interface and the combustion gases as the combustion gases flow through the outlet of the combustion chamber and into the inlet of the heat exchanger tube.

2. The appliance of claim 1 , wherein the barrier has a thickness extending between the combustion gases and the interface and a material composition so that the barrier provides sufficient thermal resistance to heat transfer between the combustion gases as the combustion gases flow through the outlet of the first housing and the inlet of the second housing to maintain a stress at the interface below a yield stress of the interface.

3. The appliance of claim 1 , wherein the interface is a swaged interface.

4. The appliance of claim 3 :
wherein the mounting bracket comprises an opening that is defined by an edge that extends about the opening,
wherein the edge of the mounting bracket that defines the opening extends away from an outer surface of the mounting bracket,
wherein the opening of the mounting bracket is configured to receive the heat exchanger tube therethrough such that an inner diameter of the edge of the mounting bracket engages an outer diameter of the heat exchanger tube to define the interface,
wherein the heat exchanger tube is swaged to form a first circumferential protrusion adjacent the inlet of the heat exchanger tube on a first side of the edge of the mounting bracket and a second circumferential protrusion on a second side of the edge of the mounting bracket that is opposite the first circumferential protrusion,
wherein a surface of the heat exchanger tube that engages the inner diameter of the edge of the mounting bracket biases into engagement with the edge, and
wherein each of the first circumferential protrusion and the second circumferential protrusion has an outer diameter greater than the inner diameter of the edge, thereby defining the swaged interface.

5. A fuel-fired heating appliance comprising:
a combustion chamber that defines an inner cavity and comprising an inlet end and an outlet end;
a burner disposed within the inner cavity and at the inlet end of the combustion chamber, the burner having at least one outlet through which hot combustion gases are exhausted into the combustion chamber;
a heat exchanger comprising a combustion output tube that is disposed at the outlet end of the combustion chamber such that the combustion output tube is in fluid communication with the combustion chamber to receive the hot combustion gases from the inner cavity of the combustion chamber;
a mounting bracket having at least one hole therethrough, the mounting bracket being coupled to the combustion chamber and the heat exchanger such that the at least one hole of the mounting bracket is aligned with an opening defined by the outlet end of the combustion chamber and the combustion output tube extends into the combustion chamber through the at least one hole of the mounting bracket and the opening defined by the outlet end of the combustion chamber; and
an insulating barrier that is configured to inhibit heat transfer from the hot combustion gases flowing through the heat exchanger to an interface between the at least one combustion output tube and the mounting bracket,
wherein the insulating barrier is disposed at the outlet end of the combustion chamber such that at least a portion of the insulating barrier is disposed in the combustion chamber while a remainder portion of the insulating barrier extends towards and into an interior of the combustion output tube between the hot combustion gases and the interface.

6. The appliance of claim 5 , wherein the interface has a yield stress, and wherein the insulating barrier has a thickness extending between the hot combustion gases and the interface, and a material composition so that the insulating barrier provides sufficient thermal resistance to heat transfer between the combustion gases as the combustion gases flow through the outlet of the combustion chamber and an inlet of the combustion output tube to maintain a stress at the interface below a yield stress of the interface.

7. The appliance of claim 5 , wherein the interface is a swaged interface.

8. The appliance of claim 7 , wherein the bracket defines a respective edge at and extending about the at least one hole that extends away from an outer surface of the mounting bracket so that, at each said hole, an inner diameter of the edge engages an outer diameter of the combustion output tube, and wherein the combustion output tube extends into the outlet end of the combustion chamber through the at least one hole and is swaged to form a first circumferential protrusion on a first side of the edge and a second circumferential protrusion on a second side of the edge opposite the first circumferential protrusion, wherein a surface of the combustion output tube that engages the inner diameter of the edge biases into engagement with the edge and wherein each of the first circumferential protrusion and the second circumferential protrusion has an outer diameter greater than the inner diameter of the edge, thereby defining a swaged interface.

9. The appliance of claim 5 , wherein the insulating barrier defines a generally cylindrical portion with annular cross sections disposed at least partially within the combustion output tube.

10. The appliance of claim 6 , wherein the combustion chamber comprises a refractory disposed therein such that the refractory encloses a volume that extends from a burner surface at which combustion occurs to the mounting bracket, wherein the refractory defines a recess therein from a surface of the refractory adjac

Assignees

• Rheem Mfg Co

Inventors

• Batson Mickey E
• Farley Darryl J
• Khatami Reza
• Mantha Divakar
• Cogburn Tyson J
• Whalen Nathan T
• Zhang Qian
• Reed Shawn A
• Shellenberger Timothy J

Classifications

• F23Q3/00

  Igniters using electrically-produced sparks (sparking-plugs H01T13/00) · CPC title

• F23D14/02 Primary

  Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone · CPC title

• F23D2203/00

  Gaseous fuel burners · CPC title

• F23D2206/00

  Burners for specific applications · CPC title

• Y02E20/30

  Technologies for a more efficient combustion or heat usage · CPC title