JPH0137642B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a combustion device that performs surface combustion on the combustion surface of a combustion tube for purposes such as heating.

Conventional technology A conventional combustion device of this type is shown in FIG.

1 is a bottomed vaporizing cylinder, a sheathed heater 2 is buried around it, a part of the bottomed part is opened, and a blower fan 3 is installed.
A thin fuel tube 6 is inserted from the middle of the tube through a fuel pump 5 from the fuel tank 4 so as to face the inside of the vaporization cylinder 1. A pre-drawn mixing plate 7 is disposed on the upper surface of the vaporizing cylinder 1, and above the rectifying cylinder 9, which has a large number of premixture jetting holes 8 inside,
A combustion cylinder 11 made of a wire mesh, a porous body, or the like is disposed through a rectifying space 10 having a minute gap. Then, the flame stabilizing plate 12 is placed on the combustion tube 11 in the upper part of the rectifying space 10.
It is installed to cover the outside. An outer cylinder 14 made of glass or the like with good heat permeability is arranged around the combustion cylinder 11 via a combustion space 13, and an exhaust ring 15 is provided at the bottom of the combustion space 13 to enclose the vaporizer cylinder 1, and an exhaust port 16 is provided. have. The upper part is closed by a flat plate-like top plate 17, and around the top plate 17 and the outer cylinder 14, ventilation passages 18 are provided vertically and horizontally, and a ventilation fan 19 is arranged at the rear. 22 is an exterior case.

In the above configuration, after heating the sheathed heater 2 in the carburetor 1 and driving the combustion fan 3, the fuel tank 4
The fuel is sucked in by the fuel pump 5, and is injected into the vaporization cylinder 1 from the fuel thin tube 6 to vaporize the fuel.
It is mixed with the combustion air from the blower fan 3, further mixed at the mixing plate 7, and flowed upward as a premixed gas. The premixture passes from the inside of the straightening tube 9 through the premixture jetting hole 8, is further straightened in the straightening space 10, and is ejected onto the surface of the combustion tube 11, where it is ignited by an igniter (not shown), and the combustion tube 11 is ignited by an igniter (not shown). A combustion fire is formed on the surface, and after the combustion reaction is further promoted in the combustion space 13, it is released as exhaust gas from the exhaust port 16 of the exhaust ring 15.

In this case, the premixture evaporated and vaporized in the high-temperature part of the vaporization tube 1 is guided into the upper straightening tube 9, but the fire formed on the surface of the combustion tube 11 heats the combustion tube 11 itself and becomes red-hot. The radiant heat dissipates both outside and inside, raising the temperature of the rectifying cylinder, which causes the temperature of the premixed air inside the rectifying cylinder to rise, reaching a very high temperature as shown by the broken line in Figure 4. It also falls within the range of 400 to 500 degrees Celsius, which is the spontaneous ignition temperature of the air-fuel mixture. If it is less than m1.2, it will cause backfire. Explosive sound during backfire, carbon monoxide,
Soot is generated, and the combustion tube 11, straightening tube 9, and vaporization section are damaged by deformation, melting, etc. In addition, in order to obtain radiant heat by surface combustion, the combustion tube 11 is
A low air-fuel ratio of 850 to 900°C is good, but it cannot be set because of the flashback range, resulting in a combustion range with a stable air-fuel ratio narrow range and little radiation.

Furthermore, in the conventional example shown in FIG.
The upper part of the outer cylinder 14 is closed by stacking them. In this case, the combustion tube 11 and the flame stabilizing plate 12 heated by the combustion gas reach a high temperature of 500°C or more, and the mixing plate 7
The premixed air jetting out from the center hits this flame-holding plate and undergoes heat exchange, resulting in an even higher temperature.

Further, the air supplied to the ventilation passage 18 passes through the flat top plate 17, but the flame holding plate 12 and the top plate 17
Since the flame stabilizing plate 12 is double-layered, the heat dissipation of the flame stabilizing plate 12 is insufficient, and the air from the blower fan 19 does not sufficiently hit the portion of the top plate 17 that overlaps with the flame stabilizing plate 12, resulting in no cooling effect.

Problems to be Solved by the Invention As described above, conventionally, the premixture of 150 to 200°C ejected from the mixing plate of the carburetor cylinder 1 becomes 400 to 500°C on the low air-fuel ratio side in the rectifier cylinder 9, and the premixed mixture flows into the combustion cylinder 1. Backfire is caused in the rectifier tube 9 from the outer surface of the rectifier tube 9.

This ensures a stable combustion state and the combustion tube 11.
It is not possible to set the temperature to a high temperature of 850 to 900℃, and a good radiant heating effect cannot be obtained.

The present invention solves such conventional problems, and aims to lower the premixture temperature by using a cooling top, and to expand the stable combustion air-fuel ratio range so as to prevent flashback and obtain a sufficient amount of radiation. do.

Means for Solving the Problems In the present invention, a top plate having a convex cooling top is provided on the top of a rectifier tube in a combustion cylinder, and an air flow is formed against the cooling top.

Effect: With this configuration, the premixture is forcibly cooled by the air flow from the blower fan, and high radiation and stable combustion width can be achieved.

Embodiment Hereinafter, an embodiment of the present invention will be described based on FIG. 2.

The same numbers as in FIG. 1 indicate the same parts. In FIG. 2, the difference from FIG. A top plate 17 with a cooling top 20 is provided and closed, and at the same time the upper part of the outer cylinder 14 is also closed,
A blower fan 19 is shown at the rear. 2
2 is an exterior case.

Figure 3 shows cooling fins 2 on the top surface of the cooling top 20.
1.

Next, to explain the operation, the sheathed heater 2 in the vaporization cylinder 1 is energized to heat the vaporization cylinder 1 to a high temperature state, and then the combustion fan 3 is driven to send combustion air into the vaporization cylinder 1. . In the same way as the combustion fan 3 is driven, the fuel pump 5 is driven from the fuel tank 4 to suck in fuel and inject it into the vaporization cylinder 1 from the tip of the fuel thin tube 6. Since the inside of the vaporization tube 1 is in a high temperature state, the ejected fuel particles are instantaneously vaporized and mixed with combustion air, further mixed by the mixing plate 7, and guided into the straightening tube 9. Note that the premixed air, which is communicated with the straightening cylinder 9 and is squeezed by the mixing plate 7 into the cooling top 20 provided on the top plate 17, is first pushed upward and dissipated to the bottom as shown by the arrow, so that it is further straightened. The premixture exits into the rectification space 10 from the premixture jet hole 8 and forms a surface combustion fire with uniform red heat in the combustion tube 11 using an igniter (not shown). The combustion gas after combustion is discharged from the exhaust port 16 of the exhaust ring 15 at the lower part, and flows through the ventilation passage 18 with the air flowing in from the rear ventilation fan 19, and is mixed with the warm air that is exchanged with the air before being mixed with the hot air. is dissipated into the body.

Here, the premixture introduced into the cooling top 20 is cooled by the cooling air from the rear blower fan 19, and heat dissipation is further promoted by the cooling fins 21, as shown by the solid line in FIG. rectifier tube 9
The temperature of the premixture inside the tank is about 80 to 90 degrees lower than that of the conventional one without the cooling top 20, and the air-fuel ratio m
In response to changes, the temperature remains below 400°C in all regions, preventing flashback and reducing the range of stable air-fuel ratios.

Effects of the Invention As described above, the present invention provides a cooling top that communicates with the rectifying cylinder in the combustion cylinder and bulges upward, and provides an exterior case to form a ventilation passage around the outer periphery of the cooling top, so that a convection blower can be connected to the cooling top. The supplied air flow is sent to the ventilation passage and hits the cooling top, producing the following effects.

(1) Adjust the premixture temperature in the straightener tube and cooling top.
It can reduce combustion by 80 to 90 degrees, prevent backfire, widen the air-fuel ratio range, and improve the stable combustion range.

(2) It is possible to improve heating efficiency by obtaining a stable radiation amount at the low air-fuel ratio m.

(3) The premixture is sufficiently rectified, eliminating uneven red heat in the combustion tube and improving combustion performance.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a conventional combustion device, Fig. 2 is a sectional view of a combustion device according to an embodiment of the present invention, Fig. 3 is a partial sketch of Fig. 2, and Fig. 4 shows the air-fuel ratio m and the rectifier tube. This is a data bluff of the internal premixture temperature. 1... Vaporizer tube, 9... Rectifier tube, 11... Combustion tube, 13
...Combustion space, 14...Outer cylinder, 17...Top plate, 19...Blower fan, 20...Cooling top, 21...Cooling fin.

Claims (1)

[Claims] 1. A bottomed carburetor having a heater, a narrow fuel tube for supplying fuel and a blower fan for supplying combustion air opened into the carburetor, and a constricted tube fixed to the top of the carburetor and through which the vaporized gas passes. A mixing plate, a rectifier cylinder having a number of premixture injection holes connected to the upper part of the vaporizer cylinder, a combustion cylinder arranged on the outer periphery of the rectifier cylinder with a rectification space in between, and a combustion space around the combustion cylinder. an outer cylinder made of glass or the like arranged through the outer cylinder; an exhaust ring having an exhaust port provided at the bottom of the outer cylinder; a top plate that closes the upper openings of the rectifier tube, the combustion tube, and the outer cylinder; A convex cooling top that bulges upward at the top of the rectifier cylinder, an exterior case that is arranged on the outside of the top plate, the cooling top, and the outer cylinder and forms a ventilation passage between these, and this ventilation. A combustion device consisting of a blower fan that supplies convective air to the passage.