JPH0215767B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to a burner that converts liquid into gas and burns it among combustion devices that use liquid fuel.
This invention relates to liquid fuel combustion devices used for space heating, hot water supply, drying, etc.

Prior Art This type of conventional vaporizer is disclosed in, for example, Japanese Patent Application No. 1983-
As shown in No. 210801, it had a configuration as shown in Figure 5. That is, in the vaporization case 1, the lower end of the suction body 2 was placed in the oil tank 3, and the oil level in the oil tank 3 was kept at a substantially constant oil level by the closed oil tank 4. Moreover, the suction body 2 is provided surrounding the heating element 5. The operating principle of such a conventional example will be explained below. The suction body 2 sucks up oil from the oil tank 3 to the vicinity of the heating element 2 by capillary action. Here, heating element 2
When electricity is applied to the oil, the heat generated causes the oil to vaporize.
This vaporized gas is conveyed to the burner 7 by air from a blower 6 provided upstream of the vaporization case 1.

Problems to be Solved by the Invention However, with such a structure, there is a problem that the amount of vaporization decreases over a lifetime.
The reason for this is explained below.

The cause of the lifetime decrease in the amount of vaporization is caused by the tar generated in the wick 2 clogging the capillary tubes of the wick 2. This tar content is generated by high-boiling components that originally exist in small amounts in the oil or by high-boiling components that are polymerized by the oil in the air. It cannot completely vaporize from the surface and remains and turns into tar. Furthermore, the latter high-boiling components are produced especially when the oil is exposed to high temperatures for a long period of time.

In the configuration of the conventional example, the heat of the heating element 5 is transferred to the absorbent body 2.
The above-mentioned phenomenon of high boiling point occurs in the absorbent body 2 because the water is transmitted downward. For example, when kerosene was used, the temperature at the top of the absorbent body 2 was in the range of 200 to 300°C, but at a point 10 mm below the bottom end of the heating element 5, the temperature of the absorbent body 2 was about 100°C.

In addition, in order to prevent such a phenomenon, if the distance between the heating element 5 and the oil surface is shortened while maintaining the conventional configuration, the temperature of the suction body 2 will decrease, but the oil surface in which the suction body is contained will decrease. As the temperature in the vicinity rose and the oil surface remained at a high temperature for a long period of time, oxidation still occurred.

Means for Solving the Problems The present invention lowers the fuel temperature in the suction body and its vicinity by giving a flow to the liquid fuel that is in contact with the lower end of the suction body, thereby preventing high-temperature oxidation of the fuel. A protruding portion is provided in a part of the suction body, and the flowing liquid fuel is sucked up by the protruding portion.

Effects The effects of this technical means are described below. That is, by imparting a flow velocity to the liquid fuel submerged below the wick, the fuel surface is prevented from becoming high in temperature due to heat transfer from the heating element.
At the same time, the flowing fuel is sucked up by the protrusion, thereby increasing the distance between the heating element and the fuel surface, thereby further preventing the fuel from becoming hotter due to heat transfer.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. The lower part of the suction body 9, which is provided to surround the outer periphery of the heating element 8, is placed in the flow of fuel in the circulation path 10. The fuel in the fuel tank 11 is sucked up by the pump 12 through the discharge pipe 13 into the circulator 10, and then passes through the lower part of the suction body 9 located at the bottom of the circulation path 10 that slopes downward from the top toward the downstream. The fuel then flows down to the fuel tank 11 through the return pipe 14. The heating element 8 is a coil-shaped resistor that is heated by electricity. The wicking body 9 is made of heat-resistant fibers such as alumina and milica, and the above-mentioned fuel is supplied to the heating element 8 from the bottom of the circulation path 10.
It is sucked up by capillary action. That is,
The heating element 8 and the suction body 9 constitute a vaporizing section that vaporizes liquid.

Combustion air is sent to the vaporization section by a blower 15 upstream of the vaporization section. Also, combustion blower 15
A part of the air does not pass through the vaporizing section, but passes through the pneumatic pipe 16 on the outer periphery of the circulation path 10, and flows toward the burner 17 from a gap 18 between the burner 17 and the connection portion of the circulation path 10. Further, the burner 18 is attached to the pneumatic pipe 16 via a heat insulating material 19.

Furthermore, the vaporization section consisting of the heating element 8 and the suction body 9 is fixed to the upper lid 20 of the circulation path 10,
By opening the pneumatic tube cover 21, the circulation path 10
It has a structure that makes it easier to attach and detach.

Further, the wicking body 9 is tightly wound around the outer periphery of the coil-shaped heating element 8, and both ends of the wicking body 9 are stacked in two layers to form a protrusion 22. This two-layered portion 22 is fixed with a heat-resistant material, a metal piece, etc., and the entire circumference of the coiled heating element 8 is covered with the absorbent body 9. This protrusion 22 serves as an oil suction part, and the cylindrical part 23 of the suction body 9 serves as a vaporizing surface. The specific operational relationship of the present invention having such a configuration will be described in detail below.

The fuel in the fuel tank 11 is sent to the circulation path 10 by the pump 12, but the fuel flows through the bottom of the circulation path 10, which has a downward slope in the downstream direction, and returns to the original fuel tank 11 through the return pipe 14. It's on. In this case, this flow rate is always greater than the amount vaporized. When electricity is started to be applied to the heating element 8, the fuel is vaporized by heating from the upper part of the suction element 9, which sucks up the fuel through the capillary tube. This amount of vaporization always has a constant relationship with the amount of electric power supplied to the heating element 8. This vaporized gas mixes with the air from the blower 15, flows to the burner 17, and is combusted. On the other hand, the air flowing around the outer periphery of the circulation path 10 flows in from the interval 18, and the vaporized gas already mixed with the air is mixed and diluted again. This pneumatic pipe 16 has an upper lid 21 with a removable vaporizing section and a gap 1
This is to prevent the vaporized gas from leaking out of the device. Also, the interval 18 is the burner 17
This prevents heat from being transferred to the vaporization section. Furthermore, the purpose of the heat insulating material 19 is also the same. The necessity of preventing this heat transfer will be discussed later.

With this configuration, since fuel always flows below the suction body 9, the protrusion 2 at the bottom of the suction body 9
2 is kept at a low temperature. The cylindrical portion 23 of the suction body 9 in contact with the heating element 8 is at a high temperature, as in the conventional case, but the lower protruding portion 22 is kept close to room temperature, so that the fuel that rises through the suction body 9 in a capillary tube. The time for the water to pass through the high temperature region of the wicking body 9 is shortened. That is, by giving the flow to the lower part, the wicking body 9
It is possible to make the temperature gradient in the vertical direction steeper, and the temperature range where it is easy to increase the boiling point is narrowed. Of course, in the present invention, the temperature of the returning fuel increases slightly, but since the fuel tank 11 is separated from the vaporizing section and the fuel tank 11 radiates heat, it does not reach a high temperature that would generate tar.

As mentioned above, in the present invention, the heating element 8 having a high temperature
Since the protrusion 22 sucks up the oil between the oil surface and the oil surface, the heat of the heating element 8 is difficult to escape downward. If there is no protruding portion 22 and oil flows into a portion of the cylindrical portion 23, the heat of the heating element 8 is absorbed by the large amount of flowing oil, raising the temperature of the oil. Of course, even if the thick suction body 9 is rolled into a cylindrical shape to form the cylindrical part 23 and the protruding part is eliminated, the distance between the heating element 8 and the oil surface will increase and it will be difficult for heat to escape, but the entire suction body 9 The heat capacity of the engine increases, causing a delay in response during ignition. Alternatively, there is a problem in that a part of the vaporized gas generated in the cylindrical portion 23 comes into contact with the oil surface and deteriorates in quality. Therefore, the absorbent body 9 constituted by the cylindrical portion 23 and the protruding portion 22 of the present invention is more preferable in terms of responsiveness, prevention of heat conduction, and gas dissipation.

To explain with an experimental example of the present invention, when the fuel is not flowing, kerosene deteriorates significantly.
℃ or more was a region 10 mm or more from the lower end of the heating element 8, but this was shortened to 3 mm by flowing. The fuel that has been oxidized due to the high temperature in this part further rises through the capillary to the suction body 9.
Vaporization occurs from the top, but in the conventional configuration in which a large amount of already oxidized high-boiling components were generated during the wicking process, the components that could not be vaporized accumulated in the vaporization section, causing capillary clogging that gradually inhibited wicking. This will reduce the amount of vaporization. The present invention improves this phenomenon.

A second effect of fluidization is an increase in the wicking capacity of the capillaries. When a stationary fluid is sucked up, only the capillary action that sucks it up due to the affinity between the wicking body and the liquid acts as a force, but in the case of a flowing liquid, the force of the liquid flow acts as a suction force as a resistance to the flow. It is attached to the upper body. In other words, a portion of capillary action + pump pressure acts as suction force. In experiments, the maximum amount that can be vaporized was improved by about 20% by fluidization.

This can be said to have made it possible for the fuel to rise to the point where it is vaporized even if the high boiling point components turn into tar and clog the capillary tubes to some extent when fluidized. Coupled with the effect of the temperature gradient described above, this makes the effect of the present invention on the lifespan remarkable.

Furthermore, as mentioned above, the purpose of thermally separating the burner 17 and the circulation path 10 is to prevent the circulation path 10 and the vaporizing section from increasing in temperature due to combustion heat.
This is one means for making the effects of the present invention more clear. Furthermore, the upper lid 20 is not simply intended to facilitate the attachment and detachment of the vaporizing section, but when the entire vaporized gas passage is integrated with the circulation path 10, the entire vaporized gas passage becomes low temperature due to cooling by the circulation flow, and the vaporized gas passage becomes low temperature. This prevents the gas from condensing and returning. Since the upper lid 20 is formed separately from the circulation path 10, it can be said that it is difficult to receive cooling from the circulation flow. Since this condensed liquid has already had a history of vaporization at high temperatures, it is significantly oxidized, and by preventing this condensation, the present invention further enhances its effectiveness. Further, in the present invention, air and fuel flow in the same direction.

This prevents the fuel from flowing in a counter-flow manner due to air resistance, which would result in an increase in the time the fuel remains in the circulation path 10. In other words, it has the effect of making the flow faster. Moreover, the reason for giving the circulation path 10 a downward slope toward the downstream is the same purpose. In addition, when the wick of the present invention supports a catalyst, the high boiling point components accumulated under the conditions of stopping the pump, energizing the heating element, and operating the blower are quickly removed, so such measures should be added. In this case, the features of the present invention become even more remarkable.

FIG. 3 shows another embodiment of the invention. Circulation path 1
A partition plate 25 having a slit 24 through which the protrusion 22 of the suction body 9 passes is provided between the upper cover 20 of the vacuum cleaner 0 and the circulation path 10. Oil circulates below the partition plate 25, and the cylindrical portion 23 faces above. This partition plate 25 prevents the gas vaporized in the cylindrical portion 23 from coming into contact with the low-temperature circulating oil flow and condensing while being carried by the conveying air. If a large amount of oil condenses, not only will the oil become hot due to the heat, but also the fuel that has been vaporized and has been exposed to sufficient oxygen (due to severe oxidative polymerization, the oil condensed from this gas will become extremely hot). (high boiling point) is unavoidable.

It goes without saying that it is desirable that the aforementioned partition plate 25 itself also be at a high temperature. Therefore, the upper lid 2
It is formed integrally with 0.

Further, the thickness of the protruding portion 22 of the suction body 99 is twice that of the cylindrical portion 23. Although this is a very natural form constituting the absorbent body 9 of the present invention, it is also an essential requirement in terms of characteristics. That is, the protrusion 2
2 is formed by stacking two layers of the remaining absorbent body 9 that has been wound around the cylindrical portion 23, but it is also possible to use four layers or one layer as shown in FIGS. 4a and 4b. Naturally, the smaller the number of layers stacked, the thinner the protrusion 22 becomes, making it difficult to transmit the heat of the heating element 8 to the circulation flow below. As a result of the experiment, the amount of vaporization proportional to the applied power cannot be obtained with one sheet due to insufficient suction amount, and when using four sheets and six sheets, the heat that is energized is transmitted downward and dissipated. Therefore, the amount of vaporization was not sufficient, and vaporization was most efficient when there were two parts, that is, the thickness of the cylindrical part and the protruding part was 1:2.

Effects of the Invention As described above, in the present invention, since the suction body imparts a flow velocity to the liquid fuel sucked up, the heat transfer from the vaporization part to the liquid fuel is relaxed, and the flowing fuel is sucked up by the protruding part. It is possible to increase the distance between the vaporization section and the fuel surface, and prevent the fuel from becoming hot.

Further, since the partition plate partitions the fuel circulation path and the cylindrical portion of the suction body, it is possible to prevent the air-fuel mixture from coming into contact with the liquid flow and condensing. Furthermore, since the wick has a thickness ratio of 1:2 between the cylindrical part and the protruding part, it can efficiently exert its vaporizing effect.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the liquid fuel combustion device of the present invention, FIG. 2 is a sectional view taken along line A-A' in FIG. 1,
FIG. 3 is a sectional view of a main part of another embodiment of the present invention, FIGS. 4a and 4b are side views of main parts for comparison, and FIG. 5 is a sectional view of a conventional example. 8... Heating element, 9... Suction body, 10... Circulation path, 12... Pump, 22... Projection, 23...
Cylindrical body, 25... partition plate.

Claims (1)

[Scope of Claims] 1. A vaporizing section composed of a heating element that generates heat when energized and a liquid fuel suction body, a blowing means for sending air for conveying vaporized gas to the vaporizing section, and a means for transporting the vaporizing section and the fuel. The suction body has a cylindrical shape having the heating element on the inner periphery, and a protrusion provided in a part of the cylindrical shape is provided to circulate the fuel between the tanks. the circulation path has a downward slope in the flow direction of the air flow sent by the blower, and the space above the liquid surface forms at least a part of the air flow path. Liquid fuel combustion equipment. 2. Liquid fuel combustion according to claim 1, wherein a partition plate is provided between the fuel circulation path and the cylindrical portion of the suction body, and an air path for conveying vaporized gas is provided between the partition plate and the cylindrical portion. Device. 3. The liquid fuel combustion device according to claim 1, wherein the ratio of the thickness of the cylindrical portion of the suction body to the protruding portion is approximately 1:2.