Radiant heater and combustion chamber

Abstract

An improved radiant heater and combustion chamber for use with radiant heating are described. The combustion chamber is made up of two different materials in different regions, an insulating portion and a conductive portion. Heat transfer is maximized through the conductive portion, whose shape can be altered to modify the radiant energy being emitted. The improved radiant heater radiates substantial amounts of heat in useful directions over large distances without the use of reflectors.

Claims

1. A radiant heater for use in a building having a ceiling and a floor, comprising: a combustion chamber having a length that is substantially tubular, wherein the combustion chamber comprises a heated conduit branch and a cold return conduit branch substantially parallel to the heated conduit branch, wherein the combustion chamber is located in the building, wherein the combustion chamber is comprised of conduit walls enclosing an inner combustion space, wherein the conduit walls consist of a metal portion and an insulating portion, wherein an upper partial circumferential portion of the conduit walls extending transversely along the length of the combustion chamber and aligned to direct heat away from the ceiling of the building is the insulating portion and a remaining partial circumferential portion aligned to direct heat toward the floor of the building is a the metal portion, wherein the insulating portion consists entirely of an insulating material, and wherein the combustion chamber lacks reflectors; an insulating housing surrounding the insulating portion, wherein the insulating housing does not contact the metal portion; a control box configured to provide heated gas into heated conduit branch and to receive cooled gas from cold return conduit branch, wherein the radiant heater is configured so that a heating of gases in the inner combustion space results in increased radiant heating through the metal portion in toward the floor of the building and away from the ceiling of the building without use of reflectors.

2. The radiant heater of claim 1, wherein the metal portion of the conduit walls is shaped to control direction of radiant heat emission from an outer surface of the metal portion.

3. The radiant heater of claim 2, wherein the insulating portion is rounded in shape and the metal portion is rounded in shape, and wherein the metal portion is positioned in a convex position relative to the insulating portion.

4. The radiant heater of claim 2, wherein the insulating portion is rounded in shape and the metal portion is flat.

5. The radiant heater of claim 2, wherein the insulating portion is rounded in shape and the metal portion is rounded in shape, and wherein the metal portion is positioned in a concave position relative to the insulating portion.

6. The radiant heater of claim 2, wherein the insulating portion is rounded in shape and the metal portion has a corrugated shape.

7. The radiant heater of claim 1, wherein an outer surface of the metal portion is treated to increase heat emitting properties.

8. The radiant heater of claim 1, wherein the metal portion is a metal alloy.

9. The radiant heater of claim 1, wherein the insulating portion is comprised of ceramic.

10. The radiant heater of claim 1, wherein the insulating portion further comprises grooves and wherein edges of the metal portion fit within the grooves to enclose the inner combustion space.

11. The radiant heater of claim 1, wherein the insulating portion is flat and the metal portion is rounded in shape.

12. A method for heating a large space in a building having a ceiling and floor using radiant heating without reflectors, comprising: passing gas through a radiant heater comprising a combustion chamber having a beginning and an end, wherein the combustion chamber comprises a conduit having a length that is substantially tubular, wherein the combustion chamber comprises a heated conduit branch and a cold return conduit branch substantially parallel to the heated conduit branch, wherein the heated conduit branch and the cold return conduit branch are connected by a return connector, wherein the combustion chamber is located in the building, wherein the combustion chamber lacks reflectors, wherein the conduit is comprised of conduit walls enclosing an inner combustion space, wherein the conduit walls consist of a metal portion and an insulating portion, wherein an upper partial circumferential portion of the conduit walls extending transversely along the length of the conduit and aligned to direct heat away from the ceiling of the building is a the insulating portion and a remaining partial circumferential portion aligned to direct heat toward the floor of the building is a the metal portion, wherein the insulating portion consists entirely of an insulating material, wherein increased radiant heating occurs through the metal portion toward the floor of the building and away from the ceiling of the building without use of reflectors, and wherein the radiant heater further comprises an insulating housing surrounding the insulating portion, wherein the insulating housing does not contact the metal portion, and a control box configured to provide heated gas into heated conduit branch and to receive cooled gas from cold return conduit branch, and wherein combustion occurs at the beginning of the combustion chamber and the heated gas cools as it passes through the length of the conduit; and passing cooled gas through the end of the combustion chamber.

13. The method of claim 12, wherein the metal portion of the conduit walls is shaped to control direction of radiant heat emission from an outer surface of the metal portion.

14. The method of claim 13, wherein the insulating portion is rounded in shape and the metal portion is rounded in shape, and wherein the metal portion is positioned in a convex position relative to the insulating portion.

15. The method of claim 13, wherein the insulating portion is rounded in shape and the metal portion is flat.

16. The method of claim 13, wherein the insulating portion is rounded in shape and the metal portion is rounded in shape, and wherein the metal portion is positioned in a concave position relative to the insulating portion.

17. The method of claim 13, wherein the insulating portion is rounded in shape and the metal portion has a corrugated shape.

18. The method of claim 13, wherein the insulating portion is flat and the metal portion is rounded in shape.

19. The method of claim 12, wherein the insulating portion is comprised of ceramic.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows a cross section of a preferred embodiment of a combustion chamber described herein;

(2) FIG. 2 shows a cross section of a preferred embodiment of a combustion chamber described herein;

(3) FIG. 3 shows a cross section of a preferred embodiment of a combustion chamber described herein;

(4) FIG. 4 shows a cross section of a preferred embodiment of a combustion chamber described herein;

(5) FIG. 5 shows a cross section of a preferred embodiment of a combustion chamber described herein; and

(6) FIG. 6 shows a perspective view of a preferred embodiment of a radiant heater described herein.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(7) The current improved radiant heater design includes a combustion chamber that is made up of a substantially tubular conduit. The conduit is comprised of conduit walls enclosing an inner combustion space. A circumferential portion of the conduit walls extending transversely along the length of the conduit is an insulating portion and a remaining circumferential portion of the conduit walls is a conductive portion. The conducting portion of the conduit walls has a substantially higher external temperature than the external temperature of the insulating portion of the conduit walls when combustion occurs within the inner combustion space, releasing substantial heat energy inside the combustion chamber, and temperatures within the conduit have reached steady-state.

(8) Alternate preferred embodiments of a combustion chamber for use in a radiant heater design are illustrated in FIGS. 1-5. FIG. 1 shows a cross section of combustion chamber 10. Combustion chamber 10 is made up of a conduit 12 having a length that is substantially tubular, as better seen in FIG. 6. Conduit walls 14 enclose an inner combustion space 15. Conduit walls 14 are made up of two different circumferential portions that extend transversely along the length of conduit 12. In particular, conduit walls 14 are made up of an insulating portion 16 comprised of a material having reduced heat conduction properties and a conductive portion 17 comprised of a material having enhanced heat conduction properties. In some embodiments, conduit walls 14 are comprised of metal, like a metal tube preferably made of a metal alloy with high operating temperature such as titanium or tantalum, and additional insulating material is affixed to an appropriate circumferential portion of conduit walls 14 to create insulating portion 16. In other embodiments, insulating portion 16 is made entirely of an insulating material such as ceramic and conductive portion 17 is made of metal.

(9) Conductive portion 17 may be configured in a variety of shapes to control the direction of heat emission, as seen in FIGS. 1-5. Insulating portion 16 may also be configured in different suitable shapes, as seen in FIGS. 1 and 5. In some embodiments, grooves 19 are included in insulating portion 16 for receiving edges 18 of conductive portion 17, which may be a metal sheet. The edges of the sheet can be curled or bent to slide into grooves 19 to enclose the inner combustion space 15. In certain embodiments, the outer surface of the conductive portion is treated to improve its heat emissivity.

(10) Heating of air or gases within inner combustion space 15 results in a substantial transfer of heat energy to the inner surfaces of conduit 12. Because the heat energy passes more effectively through conductive portion 17 to its outer surface, there is increased radiant heating through conductive portion 17 and reduced radiant heating through insulating portion 16. The increased radiant heating through conductive portion 17 occurs in a desired direction depending on the shape of conductive portion 17 and does not require the use of reflectors, nor does it involve convection or conduction. In FIG. 1, insulating portion 16 is rounded in shape and conductive portion 17 is rounded in shape and positioned in a convex position relative to insulating portion 16. Thus, in FIG. 1, across section of conduit walls 14 is generally shaped like a circle.

(11) FIG. 2 shows a cross section of an alternate embodiment of a combustion chamber 20. Combustion chamber 20 is also made up of a conduit 22 that is substantially tubular and has conduit walls 23 that enclose an inner combustion space 25. Conduit walls 23 are made up of an insulating portion 24 and a conductive portion 26, having the same properties as discussed with regard to FIG. 1. In FIG. 2, insulating portion 24 is rounded in shape and conductive portion 26 is flat. In FIG. 3, in combustion chamber 30, insulating portion 34 is rounded in shape and conductive portion 36 is rounded in shape and positioned in a concave position relative to insulating portion 34. In FIG. 4, in combustion chamber 40, insulating portion 44 is rounded in shape and conductive portion 46 is wavy, or otherwise variable in shape. In another alternate embodiment, in FIG. 5 combustion chamber 50 has an insulating portion 54 that is flat and conductive portion 56 that is rounded.

(12) An embodiment of a radiant heater 100 is shown in FIG. 6. Radiant heater 100 includes combustion chamber 110, having a substantially tubular length and U shape. In this embodiment of radiant heater 100, combustion chamber 110 is made up of heated conduit branch 112 and cold return conduit branch 114 running substantially parallel to each other. Heated conduit branch 112 and cold return conduit branch 114 are connected by way of a return connection 115. Combustion chamber 110 has conduit walls 116 enclosing an inner combustion space 111 made up of two different circumferential portions that extend transversely along the length of combustion chamber 110. In particular, conduit walls 116 are made up of an insulating portion 117 comprised of a material having reduced heat emitting properties and a conductive portion 118 comprised of a material having enhanced heat emitting properties. The shape of combustion chamber 110 can be configured to resemble any of those embodiments of combustion chambers shown in FIGS. 1-5. As discussed above with regard to FIG. 1, combustion chamber 110 can be made up of a metal tube having additional insulating material affixed to create insulating portion 117, or insulating portion 117 may be entirely made up of an insulating material such as ceramic.

(13) In radiant heater 100, insulating housing 120 surrounds insulating portion 117, while conductive portion 118 is not contacted by insulating housing 120. Radiant heater 100 also includes control box 130. Control box 130 provides heated air or gases into heated conduit branch 112 and receives cooled air or gases from cold return conduit branch 114. Control box 130 may include a burner box to heat air or gas for passage through heated conduit branch 112 and a fan to expel the cooled air or gas by forced or induced draft from cold return conduit branch 114.

(14) The design of radiant heater 100 is such that by the time air or gases return to control box 130 through cold return conduit branch 114, they are completely or nearly completely cooled. Thus, as much heat as possible has passed through conductive portion 118 of combustion chamber 110. Varying the shape, length, and volume of combustion chamber 110 allows for optimization of the radiation pattern, flow rate, and heat transfer.

(15) By way of example, without limitation, one preferred embodiment of a radiant heater uses a conduit 15 to 22 feet in length and uses a D-shaped combustion chamber such as that shown in FIG. 5. In this example, the upper portion of the conduit is the insulating portion and it consists of a ceramic plate containing slots on each side which fix and retain in position the conductive portion, which is a curved metallic radiating surface, below the plate by means of formed lips at each vertical edge. In this example, the insulating housing of the radiant heater contains additional insulation and additional structure needed to support the combustion chamber conduits for their full length. Multiple additional alternate examples of the radiant heater are possible using variations of this design and are all included within the scope of the radiant heater design described herein.