JPH0152659B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wick vaporization type liquid fuel combustion device, and its purpose is to make the combustion amount variable and to always keep the exhaust gas clean within the variable range.

In general, there are two methods for varying the amount of combustion in this type of combustion device, and the content and problems of each method will be described below.

1 Light wick height adjustment method This is a commonly used method in which the protruding height of the wick is adjusted up or down using a wick up/down device. That is,
The amount of liquid fuel vaporized is made variable by adjusting the vaporizing area of the wick, but although this method allows the amount of combustion to be adjusted, the exhaust gas is degraded.

In order to make exhaust gas clean, vaporized fuel and combustion air must be mixed in an appropriate ratio and completely combusted.
If the amount of air is insufficient, naturally the vaporized fuel will be incompletely combusted and unburned gas, soot, etc. will be emitted. In addition, if the amount of air is excessive, the excess air acts to lower the combustion temperature, and in order to make the combustion reaction inactive, components such as CO and aldehyde from the reaction process are discharged. be.

With this wick height adjustment method, the amount of fuel vaporized can be controlled, but the natural ventilation force generated by combustion heat always acts almost constant on the combustion chamber formed between the inner and outer flame tubes. Combustion air is also always supplied at a substantially constant rate.

Therefore, if the wick height is lowered, there will be excess air,
Furthermore, if the exhaust gas is made too high, there will be a shortage of air, so there is a problem in that the range in which the exhaust gas exhibits a cleanliness level suitable for practical use is extremely narrow.

According to the inventor's experiments, CO/CO ₂ (relative to CO ₂ in exhaust gas), which is an indicator of the cleanliness of exhaust gas, was found to be
The range in which the CO volume ratio) is within 0.002 is approximately 20%
(The ratio of the adjustment width to the maximum combustion amount).

2. Variable vaporizing air method This method changes the area of the air holes in the inner and outer flame tubes to adjust the amount of air supplied to the vicinity of the suction wick, thereby varying the amount of combustion.

The amount of combustion in a wick vaporization type combustion device can be controlled by the above-mentioned means of varying the vaporization area, but even if the vaporization area, that is, the protruding height of the wick remains constant, the air flow velocity in the vicinity can be changed. By changing it, you can adjust the amount of combustion.

That is, the upper end of the wick is always saturated with liquid fuel, but this liquid is vaporized depending on the degree of dryness of the surrounding area, that is, the vapor pressure difference with the surrounding area. At this time, if the area of the air hole in the outer flame tube near the lamp wick is reduced, the amount of air flowing into the vicinity of the lamp wick will be reduced, the concentration of vaporized gas near the lamp wick, that is, the vapor pressure will increase, and the amount of vaporized gas generated will be suppressed. It will be done.

In conventional examples that apply this principle,
Not only does this require a very complicated shape due to the control of the large number of air holes in the inner and outer flame tubes, but it also causes the problem of responsiveness when transitioning from strong combustion to weak combustion, which will be described below.

In other words, when intense combustion is occurring, the entire combustion tube is at a high temperature. At this time, if the air volume in the inner and outer flame tubes is varied by controlling the area of the air holes, the air amount can be instantaneously increased. Even if the temperature drops to 1, the high heat in the entire combustion tube does not drop instantly. For this reason, the residual heat from intense combustion continues to be applied to the vaporization section.

In such a situation, the vapor pressure of the fuel in the wick increases even more than the vapor pressure near the wick, and an extremely concentrated vaporized mixture gas is generated, causing temporary soot and abnormal flame. It was hot.

As the temperature of the combustion tube gradually decreases, the amount of vaporization approaches the amount of air for weak combustion, but it is not completely balanced. (This point will be explained in detail later.) In order to solve this problem of responsiveness,
Of course, various countermeasures have been considered in the past.
One example is the case where the variable air holes of the inner and outer flame tubes are limited to the vicinity of the wick, and the air holes above the wick are always fully open.

If such a method is used, even when switching from strong to weak, the temporarily high concentration mixed gas generated in the vaporizer will be able to reach the air hole above the outer flame tube while it is always fully open. Therefore, it can be completely combusted. However, this countermeasure has the opposite effect when weak combustion is stabilized.
This will give you too much air. Although this method produces less excess air than a method such as the wick height adjustment method in which all air holes are always fully open, it still causes a problem in the cleanliness of the exhaust gas. According to the inventor's experiments, the range in which CO/CO ₂ is within 0.002 is approximately 30
It was %.

The present invention eliminates the conventional drawbacks explained using the two examples above, and one embodiment thereof will be described below with reference to the drawings.

In FIGS. 1 and 2, 1 is an inner flame cylinder having a large number of air holes 1a, 2 is an outer flame cylinder having a large number of air holes 2a, and 3 is an outer cylinder surrounding the outer flame cylinder.

The wick 4 is provided between the inner wick tube 5 and the outer wick tube 6 so as to be able to move up and down by a wick up/down device 7, and its upper end protrudes into a combustion chamber 8 formed between the inner and outer flame tubes 1 and 2. I'm letting you do it.

In addition, a dish 5a and an outer flame dish 6a are formed at the upper ends of the inner core cylinder 5 and the outer core cylinder 6, respectively, and the inner and outer flame cylinders 1,
2 has been cut out.

Also, inside the inner flame tube 1 is an inner air chamber 9, and an air chamber 10 is formed between the outer flame tube 2 and the outer tube 3, and combustion air is supplied to the combustion chamber 8 through the respective air holes 1a and 2a. There is.

In addition, the core outer cylinder 6 is placed on the upper surface of the oil tank 11, and the core inner cylinder 5 is placed on the upper surface of the oil tank 11.
stands upright on the bottom surface of the oil tank 11.

Furthermore, a partition plate 12 having a ventilation hole 12a is provided at the upper end of the inner flame tube 5. A movable piece 14 having a hole corresponding to the ventilation hole 12a is provided to arbitrarily adjust the aperture ratio of the vent hole 12a between fully open and fully closed.

The support shaft 13 and the movable piece 14 are connected to the oil tank 11
It can be manually adjusted by means of the lower connecting piece 15.

In the above configuration, the combustion state will be explained below.
Liquid fuel is sucked up from the oil tank 11 to the upper end by capillary action of the lamp wick 4.

Combustion air flowing into the combustion chamber 8 through the air holes 1a and 2a forms a constant airflow near the upper end of the lamp wick 4, and transports vaporized gas downstream of the combustion chamber 8.

Combustion takes place mainly above the combustion chamber 8, and pore flames are formed around the air holes 1a and 2a. In the lower part of the combustion chamber 8, the concentration of vaporized gas is higher than the flammable range, making it difficult to form a pore flame.
It can be said that a and 2a mainly provide air for promoting vaporization, and the downstream part mainly provides air for combustion.

A combustion reaction occurs actively upstream of the combustion chamber 8, and the reaction heat heats the inner and outer flame tubes 1 and 2, and is transferred from the inner and outer flame tubes 1 and 2 to the upper end of the lamp wick by heat transfer, radiation, etc. Gives heat of vaporization.

The amount of vaporization is autonomously balanced by the feedback amount of this heat of vaporization and the vapor pressure of the air in the range determined by the flow velocity of the combustion air near the wick 4 mentioned above.

The present invention aims to always balance these two variables and make them variable, and employs the following means.

A ventilation hole 12a is provided in the partition plate 12 at the upper end of the inner flame cylinder 1.
However, if the movable piece 14 is rotated to increase the aperture ratio of the vent hole 12a, the hot air in the internal air chamber 9 in the inner flame tube 1 becomes an upward air current, and the vent hole 12a is The air rises in a larger amount and reduces the pressure inside the internal air chamber 9.

At this time, the pressure difference in the internal air chamber 9 due to the natural ventilation pressure caused by the exhaust heat generated in the combustion chamber 8 is reduced, and the amount of combustion air flowing into the entire air hole 1a is reduced.

As a result, when the amount of air supplied near the lamp wick 4 decreases, the amount of vaporization decreases, and the amount of air supplied downstream of the inner flame tube 1 is also relatively reduced, so the excess air ratio does not change. The amount of combustion can be made small and variable while generating less CO, etc. However, if this effect is the only one, it is difficult to believe that the structure is simpler than that of the second conventional example.

The key point of the present invention is that, with such a configuration, good response characteristics that could not be obtained in Conventional Example 2 are exhibited, which will be explained next.

That is, if the aperture ratio of the ventilation holes 12a is increased, the internal pressure of the internal air chamber 9 will decrease as described above. This means that the amount of outside air (atmospheric pressure) flowing into the internal air chamber 9 increases.

In other words, although the inflow amount of outside air is divided into the air hole 1a and the vent hole 12a, the amount of air passing through the vent hole 12a increases by more than the decrease in the inflow amount through the air hole 1a, and as a result, the amount of outside air passing through the air hole 12a increases by the decrease in the inflow amount through the air hole 1a. The total amount of air passing through increases.

As a result, the inner flame tube 1 is further cooled and has a lower temperature due to the aforementioned increased total amount of air. That is, if the aperture ratio of the vent hole 12a is increased,
At the same time, the inflow air of the air hole 1a decreases throughout, and at the same time, the high heat of the inner flame tube 1 instantly flows through the air hole 12a.
It is carried away and cooled by the air passing through it.

In this regard, in Conventional Example 2, since the aperture ratio of the air hole 1a is directly narrowed, not only the amount of combustion air is reduced, but also the pressure of the internal air chamber 9 is increased, and the total amount of air passing through is also reduced. On the contrary, the temperature of the inner flame tube 1 and the vaporizing section under its thermal influence is increased.

As mentioned above, the amount of vaporization is balanced by the amount of heat given to the wick 4 and the surrounding vapor pressure, so in Conventional Example 2, no matter how much the surrounding flow velocity is reduced and the vapor pressure is increased, As the temperature of the lamp wick 4 increased, the amount of vaporization exceeded the decrease in the flow velocity, and the ratio with the overall decreased air amount could not be kept constant, resulting in soot, standing flames, etc.

This phenomenon occurs as a major effect when switching to weak combustion after continuing strong combustion, due to the large residual heat, but even during steady weak combustion after switching, the internal flame The tube 1 is not cooled sufficiently and continues to vaporize in an excessive amount. As explained above in conjunction with the conventional example, the present invention reduces the amount of air in the air hole 1a as a whole, and at the same time lowers the temperature of the inner flame cylinder 1, the amount of vaporization in the vaporizing section is always near the wick 4. In proportion to the amount of air supplied to the combustion chamber, the amount of combustion air flowing in from the air hole 1a downstream of the inner flame tube 1 decreases, so the mixture ratio of vaporized gas and air does not change and complete combustion occurs. . Also, the air flowing in from the external air chamber 10 between the outer flame tube 2 and the outer tube 3 is approximately constant during this period, and has little effect on the behavior of the inner flame tube 1 side. However, if a partition plate and a movable piece are provided and interlocked with the movable piece of the partition plate on the inner flame cylinder side, the above-mentioned effect can be obtained even more significantly.

Furthermore, the same effect can be obtained even if the above-described operation is performed only in the outside air chamber 10.

When the present invention is implemented in this way, it becomes possible to obtain stable combustion over a wide range,
For example, in the above example product, the combustion range when CO/CO ₂ was 0.002 was as high as 40 to 50% (ratio of the adjustment range to the maximum combustion amount).

Furthermore, even when switching from strong combustion to weak combustion, no abnormal transient phenomenon occurs, resulting in excellent responsiveness.

Furthermore, the structure is simple, the reliability of the device is high, and the manufacturing cost is extremely advantageous.

[Brief explanation of drawings]

Figure 1 is a top view showing one embodiment of the present invention, Figure 2 is a top view showing one embodiment of the present invention;
The figure is a sectional view of the combustion section. 1... Inner flame tube, 1a... Air hole, 2... Outer flame tube, 2a... Air hole, 3... Outer tube, 4... Light wick,
5... Core inner cylinder, 6... Core outer cylinder, 5a... Inner fire pan,
6a... Outer fire pan, 7... Core up/down device, 8... Combustion chamber, 9... Inner air chamber, 10... Outer air chamber, 11...
... Oil tank, 12 ... Partition plate, 12a ... Ventilation hole, 13 ... Support shaft, 14 ... Movable piece, 15 ... Connection piece.

Claims (1)

[Claims] 1. An outer cylinder, an outer flame cylinder having a large number of air holes, and an inner flame cylinder are provided in order from the outside to the inside to form a triple cylinder, and a triple cylinder is formed below between the inner and outer flame cylinders. The upper end of the suction wick is made to protrude, a part of the air hole is opened opposite to the upper end of the suction wick, and at least one of the substantially upper part of the inner flame cylinder or the upper part between the outer cylinder and the outer flame cylinder, A liquid fuel combustion device comprising: a partition plate having a ventilation hole; and a movable piece that controls the amount of ventilation in the ventilation hole; the amount of combustion is reduced by opening the ventilation hole with the movable piece. . 2. The liquid fuel combustion device according to claim 1, wherein the movable piece is rotated.