JP2873392B2 - Radiant tube burner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a radiant tube burner used as a heating source for indirectly heating an object to be heated by radiant heat in an industrial furnace.

[Conventional technology]

In recent years, in a radiant tube burner, a radiant tube is made of ceramic instead of metal.

Ceramic radiant tubes are excellent in heat resistance and oxidation resistance, but are difficult to process and can be made only in a straight tube shape. There is a problem that cannot be improved.

Conventionally, in order to cope with such a problem, a plurality of ceramic radiant tubes are pierced in parallel in a heat treatment furnace, and one of adjacent outer ends protruding from the furnace wall is connected via a connection refractory. A known radiant tube burner is known (see JP-A-58-126918).

[Problems to be solved by the invention]

However, in the above-mentioned conventional radiant tube burner, although the thermal efficiency can be improved as compared with the one using a single radiant tube, since the connection part is outside the furnace, heat loss due to heat dissipation from this part is reduced. On the other hand, the width of the furnace includes the connection portion, and there is a problem that the ratio of the area inside the furnace to the occupied area of the furnace decreases.

Therefore, an object of the present invention is to provide a radiant tube burner that can further improve the thermal efficiency and the ratio of the area inside the furnace to the occupied area.

[Means for solving the problem]

In order to solve the above-mentioned problems, a radiant tube burner according to a first aspect of the present invention inserts a plurality of radiant tubes made of ceramics through a furnace wall in parallel into a furnace, and forms an inner end thereof at a right angle with these. Are hermetically inserted into a ceramic radiant tube having both ends closed.

In the radiant tube burner of the second invention, a plurality of ceramic radiant tubes are inserted in parallel into the furnace by penetrating the furnace wall, and the inner ends thereof are formed by short U-shaped ceramic radiant tubes. They are connected in an airtight manner.

[Action]

In each of the above means, the inner ends of a plurality of parallel ceramic radiant tubes are connected in the furnace by a ceramic radiant tube or a short U-shaped ceramic radiant tube which is perpendicular to these.

As the ceramics forming the radiant tube, SiC (silicon carbide), Si (silicon) impregnated SiC, and other ceramics having excellent thermal conductivity, strength, heat resistance and oxidation resistance are used.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a plan sectional view of the radiant tube burner of the first embodiment, and FIG. 2 is a sectional view taken along line II-II in FIG.

In the figure, 1,1 'are two radiant tubes made of Si-impregnated SiC ceramics, and the lining refractory in the heating furnace 2
It is inserted horizontally and parallel into the furnace 4 through the furnace wall 3 composed of 3a and a steel shell 3b, and a flange 1a,
It is attached to the furnace wall 3 by 1'a. A burner nozzle 5 for burning gaseous or liquid fuel is connected to the outer end of the radiant tube 1 on one side (downward in FIG. 1).

At the inner end of each radiant tube 1, 1 ', opposed diagonal cut surfaces 1b, 1'b are formed, and threaded portions 1c, 1' are formed.
c (see FIG. 3) is formed on the outer periphery. The threaded portion 1c is formed by applying an amorphous adhesive (not shown) to a radiant tube 6 made of Si-impregnated SiC ceramics whose inner ends are at right angles to the above and both ends are hermetically closed. It is hermetically inserted by 1'c.

In order to hermetically insert the inner ends of the radiant tubes 1 and 1 'into the radiant tube 6 in a right angle direction, not only the case where the threaded portions 1c and 1'c are used, but also, for example, as shown in FIG. Thus, flanges 1d, 1'd are formed at the inner ends of the radiant tubes 1, 1 ', and an amorphous adhesive (not shown) is provided between these flanges 1d, 1'd and the radiant tube 6.
May be inserted airtightly.

In FIG. 1, reference numeral 7 denotes a refractory bracket attached to the furnace wall 3 for supporting the radiant tube 6 in a right angle direction.

In the radiant tube burner having the above-described configuration, the combustion gas burned by the burner nozzle 5 flows from one radiant tube 1 through a radiant tube 6 in a direction perpendicular to the other radiant tube 1 'as shown by an arrow in the drawing.
In the state where the temperature is lowered by the effective heat dissipation during this time, the other end of the radiant tube 1 ′ is discharged as exhaust gas.

FIG. 5 is a plan sectional view of the radiant tube burner of the second embodiment.

The radiant tube burner of this embodiment is similar to that of the first embodiment in that three radiant tubes 11, 11 ', 11 "made of Si-impregnated SiC ceramics are passed through the furnace wall 3 of the heating furnace 2 to form a furnace. The inner and outer ends of the radiant tube 11 are connected to the burner nozzles 5 at right angles to the outer ends of the radiant tubes 11 at a right angle, and both ends are airtightly closed. It is airtightly inserted into a radiant tube 61 made of porous ceramics.
A cut surface 11b perpendicular to the axial direction is formed at the inner end of the central radiant tube 11, and diagonal cut surfaces facing each other are formed at the inner ends of the radiant tubes 11 'and 11 "on both sides. 11′b, 11 ″ b are formed, and inside the radiant tube 61 in the right angle direction facing the other end of the radiant tube 11 at the center, local oxidation by fire in this portion is prevented, and A hot air distribution block 8 made of refractory for distributing combustion gas is attached.

The other configuration is almost the same as that of the first embodiment. Therefore, the same reference numerals are given to the same components and the like, and the description thereof will be omitted.

In the radiant tube burner having the above-described configuration, the combustion gas burned by the burner nozzle is supplied from the center radiant tube 11 through the right-angled radiant tube 61 as shown by arrows in the figure, and the radiant tubes 11 ', 11 "
In this state, the temperature is lowered by effective heat dissipation during this time, and the exhaust gas is emitted from the outer ends of the radiant tubes 11 'and 11 "on both sides.

Here, since the tube length of the radiant tubes 11, 11 ', 11 "is substantially 1.5 times that of the first embodiment, it is necessary to further improve the thermal efficiency or the heat power of the burner nozzle 5. Can be.

FIG. 6 is a plan sectional view of a radiant tube burner according to a third embodiment.

In the radiant tube burner of this embodiment, two radiant tubes 1, 1 'made of Si-impregnated SiC ceramics are passed through the furnace wall 3 of the heating furnace 2 into the furnace 4 as in the first embodiment. A burner nozzle 5 is connected to the outer end of one (lower in the figure) radiant tube 1 and the inner ends thereof are short U-shaped radiant tubes made of Si-impregnated SiC ceramics. 62
Are connected more airtightly.

The other configuration and operation and effect are substantially the same as those of the first embodiment, and therefore, the same components and the like are denoted by the same reference numerals and description thereof will be omitted.

〔The invention's effect〕

As described above, according to the present invention, the inner ends of a plurality of parallel ceramic radiant tubes are connected in the furnace by a ceramic radiant tube or a short U-shaped ceramic radiant tube that is perpendicular to these. Therefore, unlike the conventional case, heat loss due to heat dissipation from the connection part outside the furnace does not occur, so that the thermal efficiency can be further improved, and the ratio of the furnace inner area to the furnace occupied area decreases. I can't. Also, the production becomes very easy as compared with the degree of improvement of the thermal efficiency.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a plan sectional view of a radiant tube burner of the first embodiment, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and FIG. FIG. 4 is an enlarged view of a main part of the example, FIG. 4 is an enlarged view of another embodiment, and FIG. 5 is a plan sectional view of a radiant tube burner of a second embodiment. FIG. 6 is a plan view of a radiant tube burner according to a third embodiment. 1,1 '... radiant tube, 3 ... furnace wall 4 ... furnace inside, 5 ... burner nozzle 6 ... radiant tube 11,11', 11 "... radiant tube 61,62 ... radiant tube

Claims (2)

(57) [Claims] 1. A plurality of radiant tubes made of ceramic are inserted in parallel into a furnace through a furnace wall, and their inner ends are perpendicular to the radiant tubes, and hermetically sealed to the radiant tubes made of ceramic whose both ends are closed. A radiant tube burner characterized by being inserted into a radiant tube burner. 2. A plurality of ceramic radiant tubes are inserted in parallel into the furnace through the furnace wall, and their inner ends are hermetically connected by short U-shaped ceramic radiant tubes. Radiant tube burner.