JPS6324341Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a liquid fuel combustion device that uses kerosene or the like as fuel and performs premixed vaporization combustion.

Configuration of conventional examples and their problems The vaporizing cylinder of a conventional liquid fuel combustion device, for example, a hot air heater that uses kerosene as fuel, is shaped like a cylindrical pot with a bottom, as shown in Fig. 5, and has a circumferential side surface. A primary air supply port 52 and a nozzle 53 are provided concentrically therewith, and the nozzle 53 and the constant air supply port 52 are arranged radially toward the center of the vaporization tube 51 . The bottom of the vaporizing cylinder 51 is flat, and a vaporizing cylinder lid 54, a flame port 55, and a pressure equalizing plate 56 are provided so as to cover the upper end opening of this bottomed cylindrical shape. The vaporization tube cover 54 has a tapered opening in the center, and the fuel vaporized in the vaporization tube 51 is premixed with primary air 57 in the vaporization tube 51 and is converted into a combustible gas into the vaporization tube cover 54.
is guided to the flame port 55 through the opening. Therefore, with this configuration, the dripping position of the fuel oil ejected from the nozzle 53 is concentrated on the corner portion of the circumferential side of the carburetor cylinder facing the nozzle 53 or the bottom and inner side. (Indicated by the broken line arrow in the figure.) Therefore, there was a problem in that the combustible gas concentration at the outlet of the flame port 55 became non-uniform, resulting in uneven flame. In addition, since the flow velocity of the primary air jetted out from the primary air port 52 is 10 to 15 m/s, the flow velocity does not decrease within the vaporization tube 51, the flow velocity distribution is not uniform, and it hits the side wall of the vaporization tube 51. The direction of the main jet is changed, resulting in a flow that is deflected diagonally upward toward the primary air port 52.
(Indicated by the solid line arrow in FIG. 5.) Therefore, there was a problem that the combustion gas flow velocity and the amount of combustion gas were high at the flame port 55 on the primary air port 52 side, resulting in uneven combustion.

In addition, since the bottom surface of the vaporizing cylinder 51 is flat, its heat capacity is small, and the temperature drops sharply during ignition.In order to compensate for the temperature drop, the temperature during steady combustion must be slightly higher than the optimum temperature. There was a problem. However, when the temperature of the vaporizing cylinder is raised, the vaporizing surface becomes film boiling, and the oil rolls around in the form of beads, making it difficult for the vaporizing part to remain in a fixed position, resulting in uneven and pulsating flame at the flame opening. There was a problem.

In order to solve such problems, the vaporizer cylinder 51
A protrusion 58 as shown by a dashed line is provided on the bottom surface of the
An arrangement was considered in which the fuel from the nozzle 53 collides with this protrusion 58. According to this configuration, the fuel from the nozzle 53 hits the protrusion 58 and is dispersed around the surrounding area, and the flow velocity is also reduced, making it possible to achieve uniform combustion.In addition, since the heat capacity increases by the amount of the protrusion 58, the temperature can be easily set. The above-mentioned drawbacks of the conventional technology, such as no need to increase the height, can be almost eliminated.

However, with this configuration, since the area of the top surface of the projection is narrow, the fuel in the nozzle 53 tends to splash or roll off when it hits the projection 58. Therefore, the dimensional accuracy is increased so that the fuel is directed to the center of the top surface of the projection 58. A problem arose that it had to be done.

Purpose of the invention The present invention was made in view of the above-mentioned problems, and aims to improve the uniformity and stability of combustion and to obtain a good vaporization effect.

Structure of the Invention In order to achieve the above object, the present invention provides a protrusion on the bottom surface of the vaporizing cylinder, and also provides minute irregularities on the upper surface of the protrusion.

DESCRIPTION OF EMBODIMENTS One embodiment will be described below with reference to FIGS. 1 to 4. In FIG. 1, reference numeral 1 denotes a bottomed cylindrical vaporization cylinder, which is made of die-cast aluminum with a sheathed heater 1a cast in the vicinity of its upper open end, and has a protrusion 1b on its inner bottom surface. This protrusion 1b is fixed to the inner bottom surface of the vaporization cylinder by press fitting or the like, and can be attached or detached using a tool or the like. Also, this protrusion 1
Like the vaporizer cylinder 1, b is made of aluminum, which has high thermal conductivity, and its upper end surface has countless fine irregularities formed by spraying or etching a metal with a relatively low melting point, such as aluminum. There is. Further, this upper end surface is set to be above the locus of the oil jetted from the nozzle 2, and the lower part is a base having a relatively large radius.

Reference numeral 2 denotes a nozzle provided through the circumferential wall of the vaporization cylinder 1, one end of which opens into the vaporization cylinder 1, and the other end connected to the oil feed pipe 3. Reference numeral 4 denotes an oil pump that sends the oil in the oil tank 5 to the nozzle 2 via the oil pipe 3.
It is now being supplied to 6 is a primary air port, and 7 is a duct that guides air from the combustion blower 8 to the vaporization cylinder 1. A part of the air is sent to a secondary duct 7a branching from a part of the duct 7 below the burner case 9. It is connected to. The connection portion of the duct 7 with the vaporization cylinder 1 is a throat 10 having an inner diameter reduced at the open end. 11 is the flame mouth, 1
2 is a pressure equalizing plate formed of punching metal or the like, and 13 is a vaporizer cylinder lid that fits into the upper open end of the vaporizer cylinder and is attached with screws.

In the above configuration, the air blown from the combustion blower 8 passes through the duct 7 and is guided to the throat 10, reaches a maximum flow velocity at the throat 10, and is ejected from the open end in the vaporization cylinder 1. Also, the secondary air is part of the duct 7.
It branches off from a and is guided to the burner case 9, where it helps stabilize combustion. On the other hand, fuel oil is sucked from the oil tank 5 by the oil feed pump 4 and is supplied to the nozzle 2 via the oil feed pipe 9. Here, due to the spraying effect of the throat part 10, 100
It would be desirable if it became finer and atomized, but
Since the oil is sent at a constant pressure from the oil pump 4,
The oil coming out of the nozzle 2 has a significant dynamic pressure.
Therefore, most of the oil is ejected into the vaporizer cylinder 1 as a single jet stream. The ejected oil collides with a protrusion 1b provided on the bottom surface of the vaporizer cylinder facing the nozzle 2, and is dispersed and atomized or vaporized. Further, the atomized fuel that is not vaporized due to the collision with the protrusion 1b and is dispersed around the atomized fuel collides with substantially the entire inner circumferential surface of the vaporization cylinder 1, where it is vaporized. Here, since the upper surface of the protrusion 1b is provided with minute irregularities, the surface temperature is microscopically lowered, the wettability of the jetted oil is improved, and most of the oil is stably vaporized on this upper surface. do. Therefore, the effective vaporization area becomes large and the vaporization surface is no longer concentrated in one point, resulting in less temperature drop and improved tar resistance.

Further, the dynamic pressure is reduced by the dispersion effect of the protrusion 1b, and the main jet flow becomes a jet flow directed almost directly upward. Therefore, the flame distribution at the flame port 11 becomes very uniform, and there is no problem where the flame is in close contact with one side of the flame port 11 while the other flame is lifted. In addition, if the protrusion 1b is made into a hollow conical truncated column and its base is enlarged, it has the effect of backing up the heat capacity against the sudden temperature drop at the time of ignition.Also, during normal combustion, the surface of the protrusion 1b has a large distance from the heat receiving part, so the temperature increases. Since the bottom surface can be lower than that of a flat surface, film boiling does not occur. Therefore, the average vaporizer temperature can be expressed as
Since it can be set 10℃ higher, tar resistance is improved and the problem of unstable combustion at low temperatures is eliminated.

By the way, the protrusion 1b that exhibits such an effect is fixed by screwing or press-fitting, and is detachable. Therefore, uneven processing of the projection 1b by aluminum thermal spraying, etching, etc. can be done extremely easily and inexpensively, and can be done only on the necessary and sufficient upper end surface. In addition, if tar adheres to the inner surface of the vaporizer cylinder and the protrusion 1b after long-term use, it is sufficient to remove the protrusion 1b, and as a result, the inner surface of the vaporizer cylinder 1 is cleared of obstructions and tar can be easily removed. And you can definitely do it. Further, if the tar attached to the protrusion 1b cannot be removed, it can be replaced with a new protrusion.

FIG. 4 shows another embodiment, in which the protrusion 1b has a long circular cross section in the ejection direction of the nozzle 2. Therefore, according to this embodiment, even if the drop position of the oil jetted from the nozzle 2 varies in the jetting direction, it is possible to cover a wide range, and as described above, it is possible to prevent sudden excessive temperature of the vaporizer cylinder. By preventing film boiling due to the temperature drop of the vaporizing surface during steady combustion, stable combustion can be achieved, tar resistance can be improved, and life can be extended.

In each of the above embodiments, cast aluminum such as aluminum die casting was used as the material, but it may also be made of something like cast iron. Also, although the protrusion 1b was split, it could be machined integrally with the vaporizing cylinder. It is a good thing.

Effects of the Invention As described above, according to the present invention, the wettability of the upper end surface of the protrusion is improved, so that stable vaporization can be achieved on this surface, and uniform combustion can be achieved, as well as stable combustion. In addition, the back-up of the heat capacity has the effect of preventing sudden temperature drops, and since there is no need to set the temperature of the vaporization cylinder too high, film boiling is prevented, improving tar resistance and combustion stability. There is a similar effect. In particular, in the present invention, the upper surface of the protrusion is provided with irregularities to increase the vaporization area, thereby reducing the amount of vaporization per unit area and improving the wettability of the fuel. Therefore, it is possible to provide a combustion device with high stability and excellent tar resistance with less tar adhesion.

Furthermore, if the projections are made removable, they can be made at low cost and have the advantage of improving maintainability.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram of a combustion device according to an embodiment of the present invention, Fig. 2 is a half-mounted perspective view of the same vaporizer cylinder, Fig. 3 is an enlarged sectional view of the same main part, and Fig. 4 is another embodiment. FIG. 5 is a schematic diagram of a conventional combustion apparatus. 1... vaporizer cylinder, 1b... protrusion, 2... nozzle,
8...Blower for combustion.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A vaporizing cylinder that preheats and vaporizes liquid fuel, a nozzle that opens near the inner circumferential wall of the vaporizing cylinder that supplies fuel to the vaporizing cylinder, and a nozzle that is arranged coaxially with the nozzle. a combustion blower that supplies combustion air to the carburetor;
At the center of the inner bottom of the vaporizing cylinder, there is a protrusion whose upper surface is located below the nozzle and is spaced apart from the nozzle opening end, and on which the liquid from the nozzle is sprinkled. A liquid fuel combustion device with uneven parts. (2) The liquid fuel combustion device according to claim 1, wherein the protrusion is removably provided at the center of the inner bottom of the vaporizing cylinder.