JPH0240927B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an apparatus for vaporizing and combusting liquid fuel, and is used in fields such as space heating, hot water supply, heating, and drying.

Prior Art This type of conventional vaporizer is disclosed in, for example, Japanese Patent Application No. 1983-
As shown in No. 210801, the structure was as shown in Figure 3. 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,
When the heating element 2 is energized, the oil is vaporized by the heat generated. 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, such a structure has the problem that the amount of vaporization decreases over its 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 point components that originally exist in the oil in small amounts or by high boiling point components that are polymerized by the oil in the presence of oxygen in the air. It does not completely evaporate 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 using kerosene, the temperature at the top of the wicking body 2 was in the range of 200 to 300°C, but the temperature at the top of the wicking body 2 was 10 mm below the bottom end of the heating element 5.
The temperature was approximately 100℃. 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 temperature of the oil containing the suction body will decrease. As the temperature near the oil surface increased and the oil surface remained at high temperature for a long period of time, oxidation still occurred.

The present invention solves these conventional problems by reducing the oil temperature in the absorbent body and its vicinity.
The purpose is to prevent high temperature oxidation of oil.

Means for Solving the Problem The means of the present invention for solving the problem is to provide a flow to the oil below the wick.

Effect The effect of this technical means is as follows.

That is, by imparting a flow velocity to the oil below the wick, the oil surface is prevented from becoming high in temperature due to heat transfer from the heating element. It also has the effect of narrowing the high temperature region that occurs in the lower part of the wicking body, and prevents the oil from increasing its boiling point due to oxidative polymerization.

Embodiment An embodiment of the present invention will be described below with reference to FIG. 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 the fuel circulation path 10. The fuel in the fuel tank 11 is passed through the lower part of the suction body 9 in the circulation path 10 through the discharge pipe 13 by the pump 12, and is returned to the fuel tank 11 through the return pipe 14.
flows down to 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 silica, 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. In addition, a part of the air from the combustion blower 15 does not pass through the vaporizing section, but instead flows through the pneumatic pipe 16 on the outer periphery of the circulation path 10.
, and flows toward the burner 17 from the gap 18 between the burner 17 and the circulation path 10 . Further, the burner 17 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 is easier to attach and detach.

The specific operational relationship of the embodiment 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.
I'm returning to 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 by capillary action. The amount of vaporization always has a constant relationship with the amount of electric power applied. 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 includes an upper lid 20 with a removable vaporizer and a space 18.
This is to prevent vaporized gas from leaking out of the device. Moreover, the gap 18 prevents the heat of the burner 17 from being transferred to the vaporizing 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 such a configuration, since fuel is always flowing above the absorbent body 9, the lower part of the absorbent body 9 is kept at the bottom temperature. The wicking body 9 in contact with the heating element 8 is at a high temperature, as in the conventional case, but since the lower part is kept close to room temperature, the fuel rising through the wicking body 9 due to capillary action is absorbed by the wicking body 9. The time it takes to pass through a high temperature area is shortened. That is, by providing a flow in the lower part, it is possible to make the temperature gradient in the vertical direction of the absorbent body 9 steeper, thereby narrowing the temperature range where the boiling point is easily raised. Moreover, local temperature increase in the fuel tank 11 itself, which occurs when the fuel in which the suction body 9 is soaked, does not occur occurs. 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.

To explain with an example of the present invention, when the fuel is not flowing, kerosene deteriorates significantly at 100℃.
The area where the area becomes more than
Shortened to mm. The fuel that has been oxidized due to the high temperature in this part further rises through the capillary tube and is vaporized from the upper part of the wicking body 9. However, in the conventional configuration in which a large amount of already oxidized high-boiling point fuel is generated in the wicking process,
Components that cannot be completely vaporized accumulate in the vaporizing section, gradually clogging the capillary tubes that inhibit wicking, and reducing 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 and the vaporizing section from becoming high in temperature due to combustion heat, and this is one means to further clarify the effects of the present invention. be. Furthermore, the upper lid 20 is not simply intended to facilitate attachment and detachment of the vaporizing section; 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 path, and the vaporized gas passage becomes low temperature. This prevents gas from condensing and returning. Upper lid 20
Since it is formed separately from the circulation path 10, it is difficult to receive cooling from the circulation flow. Since this condensed liquid has 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 amount of time the fuel remains in the circulation path 10. In other words, it has the effect of making the flow faster. Moreover, the reason why the circulation path 10 is given a downward slope is also for the same purpose. In addition, when a platinum group catalyst is supported on the absorbent body of the present invention, high boiling point components accumulated under the conditions of stopping the pump, energizing the heating element, and operating the blower are quickly removed. If means are added, the features of the present invention will become even more remarkable.

Effects of the Invention As described above, in the present invention, since the liquid flows through the circulation path where a part of the absorbent body of the vaporizing section faces, the temperature of the absorbent body and its vicinity is reduced, and the amount of vaporization is increased by increasing the boiling point of the liquid fuel. The lifespan of can be significantly extended.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the liquid fuel combustion apparatus of the present invention, FIG. 2 is a sectional view taken along line A-A' in FIG. 1, and FIG. 3 is a sectional view of a conventional example. 8... Heating element, 9... Suction body, 10... Circulation path, 12... Pump.

Claims (1)

[Scope of Claims] 1. A heating element that generates heat when energized is connected to a liquid fuel circulation path provided below the heating element, and the liquid fuel in the circulation path is sucked up to the heating element and vaporized. a suction body, a pipe and a pump that supply fuel from an oil tank to the circulation path, return the fuel from the circulation path to the oil tank, and cause the liquid fuel in the lower part of the suction body to flow while the heating element is energized. A liquid fuel combustion device comprising a turnpipe, a combustion air blower and a burner provided upstream and downstream of the suction body and circulation path. 2. The liquid fuel combustion device according to claim 1, wherein the direction of the vaporized gas conveying air and the circulation flow in the vaporizing section are the same. 3. The liquid fuel combustion device according to claim 1, wherein the circulation path of the vaporization section has an upstream portion inclined upward relative to the downstream portion.