JPS6143064Y2 - - Google Patents

Description

[Detailed description of the invention] The invention relates to a radiant tube burner,
In particular, the present invention relates to a radiant tube burner for preheating combustion air.

A typical prior art is the radiant tube burner shown in Japanese Utility Model Publication No. 52-50442, in which an inner tube and an outer tube are constructed in a double ring shape.
A burner is inserted into the proximal end of the inner tube, and is configured to move exhaust gas from the free end to the proximal end to preheat the combustion air.In order to improve this thermal efficiency, a helical fin is installed. is used.

In such prior art, the pressure loss is increased by the spiral protrusion, and therefore more energy is required to suck the combustion exhaust gas, and there is a risk that the combustion state of the burner may become unstable.

The purpose of this invention is to effectively recover the sensible heat of exhaust gas to preheat combustion air and improve thermal efficiency, as well as to reduce pressure loss in the combustion air and exhaust gas passages, and to improve exhaust gas suction. To provide an improved radiant tube burner that requires less energy and stabilizes the combustion state of the burner.

In the present invention, the inner tube 6 and the outer tube 7 have linear axes and are configured in a concentric double tube shape, and the inner tube 6 has a first large diameter portion 8 on the proximal end side and a free end portion. The burner body 3 is inserted into the first large diameter portion 8, and the outer surface of the burner body 3 and the first large diameter portion 8 are connected concentrically via a first step 26. An annular flow path 10 is formed between the outer tube 7 and the inner surface of the outer tube 10, which is open to the atmosphere at the proximal end side, and the outer tube 7 surrounds the first large diameter portion 8 at a distance radially outward. a second large diameter portion 11 that is concentrically connected to the second large diameter portion 11 via a second step 27 and surrounds the first small diameter portion 9 radially outwardly at a distance; A hemispherical crown-shaped closing portion 13 that is spaced apart in the axial direction of the portion 12 and the first small diameter portion 9 and closes the end of the second small diameter portion 12, convex outward in the axial direction. The first step 26 is offset from the second step 27 in the axial direction toward the base end, and further protrudes outward in the radial direction on the outer surface of the first large diameter portion 8. a plurality of first fins 16 extending in the circumferential direction and fixed at intervals in the circumferential direction; and protruding radially inward on the inner surface of the first large diameter portion 8, extending in the axial direction and located at the same position as the first fins 16 It has second fins 17 fixed at intervals in the circumferential direction and an opening 23 corresponding to the flow path 10, and the proximal ends of the first large diameter portion 8 and the second large diameter portion 11 are annularly shaped. an end plate 14 that closes the second large diameter portion 11; a connecting pipe 18 that extends radially outward and is connected to the second large diameter portion 11; a constricted portion 24 of the ejector 2; a nozzle 19 that supplies air from the base end side; and an enlarged part 25 formed on the opposite side of the nozzle 19 with respect to the constriction part 24, between the vicinity of the tip of the nozzle 19 and the constriction part 24. This is a radiant tube burner characterized in that a connecting pipe 18 is connected to the radiant tube burner.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an embodiment of the present invention.
In this radiant tube burner, the inside of the radiant tube 1 is under negative pressure due to the suction effect of the ejector 2, and the fuel supplied to the burner body 3 is combusted by the combustion air drawn from the atmosphere. The combustion exhaust gas passes through the combustion chamber 4 and the gas flow path 5 and is discharged from the ejector 2.

FIG. 2 is a sectional view taken along the section line - in FIG. 1. The radiant tube 1 basically consists of an inner tube 6 and an outer tube 7 arranged in a concentric double tube shape. The inner tube 6 has a large diameter portion 8 and a small diameter portion 9 concentrically connected via a step.
Burner body 3 toward the inside of combustion chamber 4 in small diameter portion 9
is inserted. With the burner body 3 inserted into the large diameter portion 8, the outer surface of the burner body 3 and the large diameter portion 8
An annular air flow path 10 is formed between the inner surface of the holder and the inner surface of the holder, the one end of which is open to the atmosphere (the left end in FIG. 1).

The outer tube 7 includes a large diameter portion 11 corresponding to the large diameter portion 8 of the inner tube 6 and a small diameter portion 12 corresponding to the small diameter portion 9 of the inner tube 6, which are concentrically connected via a step. At the end of 12 there is a small diameter portion 9 of the inner tube 6.
A closing portion 13 is integrally provided to cover the end portion of.
This closing portion 13 is formed in the shape of a hemispherical crown. The space between the end of the large diameter portion 11 and the end of the large diameter portion 8 of the inner tube 6 is closed by an annular end plate 14 that can be attached and removed. In this way, an annular gas flow path 5 is formed between the outer surface of the inner tube 6 and the inner surface of the outer tube 7.
is formed. The gas flow path 5 and the combustion chamber 4 communicate with each other via a gap 15 formed between the inner surface of the closing portion 13 and the end of the small diameter portion 9.

Fins 16 projecting outward in the radial direction and extending in the axial direction are fixed to the outer surface of the large diameter portion 8 of the inner tube 6 at intervals in the circumferential direction. Furthermore, fins 17 that protrude radially inward and extend axially are fixed to the inner surface of the large diameter portion 8 at intervals in the circumferential direction.

A connecting pipe 18 communicating with the gas flow path 5 is connected near the end of the large diameter portion 11 of the outer tube 7 . The ejector 2 is connected to this connecting pipe 18 . A conduit 20 for supplying air is connected to the nozzle 19 of the ejector 2. Further, a pipe line 21 for supplying fuel is connected to the burner body 3.

The closing portions 13 form gaps 15 at intervals in the axial direction of the small diameter portion 9, close the ends of the small diameter portion 12, and are formed to be convex toward the outside in the axial direction (to the right in FIG. 1). ing. The step 26 is shifted from the step 27 toward the base end (to the left in FIG. 1) along the axial direction. As is clear from FIG. 2, the fins 16 and 17 are formed at the same position in the circumferential direction, thereby improving heat conduction. The connecting tube 18 extends radially outward (upward in FIG. 1) near the proximal end of the trapezoidal portion 11. The ejector 2 has a nozzle 19 that supplies air from the base end side (left side in FIG. 1) toward the constriction part 24.
An enlarged portion 25 is formed on the opposite side. Connecting pipe 18
is connected between the vicinity of the tip of the nozzle 19 and the constriction portion 24 .

In such a radiant tube burner, when air is ejected from the nozzle 19, the resulting negative pressure acts on the air flow path 10 via the connecting pipe 18, the gas flow path 5, and the combustion chamber 4. Therefore, air is sucked from the open end of the air flow path 10 and is supplied to the burner body 3 as combustion air. At this time, the combustion exhaust gas is sucked into the ejector 2 through the combustion chamber 4, the gap 15, the gas flow path 5, and the connecting pipe 18. Therefore, the large diameter portion 8 of the inner tube 6
Heat exchange occurs between the air and the combustion exhaust gas through the side walls of the combustion chamber. Furthermore, since the large diameter portion 8 is provided with the fins 16 and 17, the heat exchange is efficiently performed. Therefore, the air flowing through the air flow path 10 is efficiently preheated and guided to the combustion chamber 4. Therefore, the sensible heat of the combustion exhaust gas is effectively recovered and the overall thermal efficiency is improved.

Since the inside of the radiant tube 1 is under negative pressure due to the suction action of the ejector 2, even if the outer tube 7 is damaged, flame and combustion exhaust gas will not blow out from the damaged portion. Therefore, when the radiant tube burner of the present invention is attached to the furnace wall to heat the inside of the furnace, the flame and combustion exhaust gas are prevented from having an adverse effect on the object to be heated.

The air passage 10 is open to the atmosphere and has a simple structure without complicated piping, and the end plate 14 can be attached and detached freely.
The inner tube 6 can be easily extracted from the outer tube 7. Therefore, maintenance work on the radiant tube 1 is easy.

As described above, according to the present radiant tube burner, the overall thermal efficiency is improved, and the simple structure facilitates maintenance work.

In particular, in the present invention, the first fin 16 and the second fin 17 protrude outward in the radial direction and extend in the axial direction, and are fixed to the first large diameter portion 8 at the same position in the circumferential direction. It is possible to reduce pressure loss and improve heat conduction, thereby improving thermal efficiency. By being able to reduce pressure loss,
The energy required to suck exhaust gas can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a sectional view taken along the cutting plane line - in FIG. 1. 1...Radiant tube, 2...Ejector,
3... Burner body, 5... Gas flow path, 6... Inner tube, 7... Outer tube, 10... Air flow path, 16, 17
...Fin.

Claims (1)

[Claims for Utility Model Registration] The inner tube 6 and the outer tube 7 have linear axes and are configured in a concentric double tube shape, and the inner tube 6 has a first large diameter portion 8 on the proximal end side. , and a first small diameter portion 9 on the free end side are concentrically connected via a first step 26, and the burner body 3 is inserted into the first large diameter portion 8, and the outer surface of the burner body 3 and the first small diameter portion 9 are connected concentrically via a first step 26. An annular flow path 10 that is open to the atmosphere at the base end side is formed between the inner surface of the large diameter portion 8 and the outer tube 7 extends from the first large diameter portion 8 outward in the radial direction. a second large-diameter portion 11 that surrounds the second large-diameter portion 11 with a gap in between; The second small diameter portion 12 is spaced apart from the first small diameter portion 9 in the axial direction to form a gap 15, the end of the second small diameter portion 12 is closed, and the second small diameter portion 9 has a convex hemispherical crown shape facing outward in the axial direction. The first step 26 is offset from the second step 27 toward the proximal end side in the axial direction, and further radially outwards on the outer surface of the first large diameter portion 8. a plurality of first fins 16 that protrude, extend in the axial direction, and are fixed at intervals in the circumferential direction; and a plurality of first fins 16 that protrude inward in the radial direction, extend in the axial direction, and It has a second fin 17 fixed at the same position with an interval in the circumferential direction, and an opening 23 corresponding to the flow path 10, and each proximal end of the first large diameter portion 8 and the second large diameter portion 11. an end plate 14 that annularly closes the second large diameter portion 11; a connecting pipe 18 extending radially outward and connected near the base end of the second large diameter portion 11; It has a nozzle 19 that supplies air from the base end side toward the part 24 , and an enlarged part 25 formed on the opposite side of the nozzle 19 with respect to the constriction part 24 . A radiant tube burner characterized in that a connecting pipe 18 is connected between the radiant tube burner and the radiant tube burner.