JPS589041Y2 - combustion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a combustion device suitable for elongated combustion chambers such as radiant tubes.

Conventional radiant tubes have the disadvantage that the fuel and combustion air burn as a high-temperature flame at the beginning of the tube, and therefore the firepower decreases and the temperature becomes low at the end of the elongated tube.

In the combustion device of the present invention, since fuel is supplied to the neck of the radiant tube and/or air is supplied in a pulsed manner repeatedly, combustion is started at a non-stoichiometric air ratio at the beginning of the radiant tube. - to prevent the fuel from being completely burned out by creating a hot flame; unburnt fuel is poured into the rear part of the tube to combine with oxygen in the combustion gas and to cause gradual combustion; Combustion takes place over the entire length of the long, thin radiant tube, creating the appearance of a long flame.This long flame has a uniform temperature throughout the length of the tube, with no particularly hot parts. Since the radiant tube can be combusted at a constant temperature, the radiant tube can be uniformly red-hot.

Further, as a result of such combustion, the amount of NOx in the exhaust gas can be significantly reduced.

FIG. 1 shows an embodiment of the structure of the combustion device of the present invention;
This will be explained with reference to FIGS. 5 and 6.

In FIG. 1, 1 is a furnace wall, and 2 is a U-shaped radiant tube with a total length of about 5 m.

A fuel nozzle 3, an air nozzle 4, and a pilot burner 5 are provided at the neck of the radiant tube.

The tail 6 of the radiant tube is continuous with the combustion gas pipe 7, which is taken out to the outside through the furnace wall 1, passes through the heat exchanger 8, and is continuous with the exhaust pipe 10.
The combustion gas is exhausted after exchanging heat with the air supplied from the combustion air supply pipe 9 through the heat exchanger.

The inventor first installed electromagnetic pulp in the fuel supply pipe 11,
The electromagnetic valve is frequently opened and closed by a pulsed current from a power source, and therefore the fuel is supplied from the fuel injection port 3 in a pulsed manner as shown in FIGS. 2 and 3. ing.

In this combustion method, the fuel supply from the fuel nozzle is as follows:
For example, the supply is a pulse type with a cycle of 0.2 seconds, and after 0.1 seconds of supply A with high fuel concentration, B with zero fuel concentration or supply C with low fuel concentration continues for o and i seconds. It's supply.

When a lump of fuel is supplied with a high concentration of fuel, it is difficult for the surrounding combustion air to reach the center of the fuel lump, so the mixing and combustion of fuel and air at the beginning of the radiant tube is difficult due to excess air. In this state, combustion occurs only at the outer periphery of the fuel mass, and combustion begins gradually.

Therefore, by supplying fuel in this manner, it is possible to prevent the entire amount of fuel from burning at a high temperature at the beginning of the conventional graft tube.

The remaining unburnt fuel is burned in the combustion gas after the radiant tube while gradually mixing with air.

As shown in Figure 4, at the beginning of this long and narrow radiant tube, the flames flow as a continuous mass, but when they reach the end of the tube, the preceding and succeeding flames connect to form a continuous flame. It flows.

In conventional radiant tubes, the fuel creates a high-temperature zone towards the end of the radiant tube and burns vigorously, and therefore the firepower tends to decline in the rear part of the radiant tube, making the flame longer inside the radiant tube. Various measures have been taken for this purpose.

In the combustion method of the present invention, a long flame with a uniform temperature can be produced over the entire length of the radiant tube simply by providing a fuel pulse supply device.

However, in carrying out this invention, the fuel supply pipe 11
The electromagnetic pulp must be opened and closed several to several dozen times per second according to demand, and even if an automobile poppet valve is used instead of the electromagnetic pulp, the opening and closing operation is purely mechanical. Even if we do, there are concerns about its useful life and reliability.

The combustion device of the present invention is shown in the enlarged front view of the radiant tube seen from the combustion side shown in FIGS. A number of fuel injection holes 3 are provided in the fuel supply pipe, and a disk 12 having holes or notches around the periphery is placed close to the tip surface, as shown by the dotted line, on the inner side of the tip surface and close to the injection holes. establish.

The disk has a shaft 13 as shown in FIG. 1, and the shaft is mechanically rotated by a motor 14, so that the fuel flows out of each jet port 3 in pulses in a continuous manner in the form of clumps. This is the combustion equipment supplied.

Although the combustion devices shown in Figures 1, 5, and 6 above are ones in which fuel is supplied in a continuous pulse manner, the same effect can be obtained even if air is supplied in a continuous pulse manner. It can also be obtained by alternately supplying fuel and air in pulses.

FIGS. 7 and 8 are enlarged views showing a combustion device according to the present invention that continuously supplies air in a pulsed manner.

FIGS. 9 and 10 are enlarged views showing a combustion device according to the present invention that alternately supplies both fuel and air in a pulsed manner.

In the case of FIGS. 7 and 8, and in the case of FIGS. 9 and 10, the disk 12 is moved along the outside of the tip surface of the fuel supply pipe 11, as shown by the solid line in FIGS. 8 and 10. Provided close to the surface.

The shaft 13 of the disk passes through the distal end surface of the fuel supply pipe 11, passes through the inside of the fuel supply pipe 11, and is rotated by a motor (not shown).

In the combustion device of the present invention, by providing an extremely simple mechanical disc rotation means in the conventional combustion device, it is possible to reliably and durablely supply pulses of fuel and/or air p1 to the elongated combustion chamber. It is possible to maintain a uniform temperature over the entire length of the radiant tube, and the amount of NOx generated can be greatly reduced, and it can be applied not only to radiant tubes but also to general combustion furnaces. This makes it possible to reduce NOx.

[Brief explanation of the drawing]

FIG. 1 is a side view of a combustion device according to the present invention attached to a radiant tube, and FIGS. 2 and 3 are graphs showing fuel pulse supply over time on the horizontal axis. Figure 4 is a diagram showing the combustion state inside the radiant tube, Figures 5 and 6 are an enlarged front view of the combustion device of the present invention that continuously supplies fuel in a pulsed manner, as seen from the combustion side, and Figure 7. , FIG. 8 is an enlarged side sectional view and an enlarged front view seen from the combustion side of a combustion device according to the present invention that continuously supplies air in a pulsed manner.
FIGS. 9 and 10 are an enlarged side sectional view and an enlarged front view as seen from the combustion side of a combustion apparatus according to the present invention which alternately supplies both fuel and air in a pulsed manner. 1 is the furnace wall, 2 is the radiant tube, 3 is the fuel injection port,
4 is an air jet nozzle, 5 is a pilot burner, 11 is a fuel supply pipe, 12 is a disk, 13 is a shaft, and 14 is a motor.

Claims (1)

[Scope of utility model registration request] A thermal sintering device having one or several fuel nozzles and one or several air nozzles is pressed, and the fuel nozzles and/or
Alternatively, a disk having 1 (11t) or several holes or notches is provided around the air outlet at a position in front of or on the front side of the air outlet, and a means for rotating the disk is provided, and the holes or notches in the disk are provided. Fuel outlet and/or
Or a combustion device characterized by a structure that supplies a fuel button and/or air in a pulsed manner by opening and closing an air jet port.