JPH0318084B2 - - Google Patents

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to a vaporization device for a liquid fuel combustion device mainly used for domestic hot water supply, space heating, etc. The present invention relates to a liquid fuel combustion device equipped with a liquid fuel vaporization device capable of forming a stable combustion flame.

(Prior Art) In recent years, combustors that heat and vaporize liquid fuel such as kerosene using an electric heater or the like and burn it have become widely used as liquid fuel combustors for room heating or hot water supply. This type of combustor is characterized by the ability to vaporize liquid fuel in advance and supply it to the burner in the form of gas, making it easy to perform premix combustion and enable clean combustion like a gas combustor. Various shapes have been considered for the vaporizer that vaporizes this liquid fuel depending on the application and the shape of the burner, but among them, the shape is simple for Bunsen burners, and the positioning of the nozzle and burner is easy. Cylindrical shapes are often used because they are simple. However, when used in a Bunsen burner, a nozzle that spouts vaporized gas is required to suck in the primary air, but tar components of the liquid fuel adhere to the small holes of this nozzle, reducing the amount of combustion or stopping combustion. Problems such as this could occur. Therefore, as a countermeasure for such a combustor, a cleaning rod is operated to clean the nozzle hole when combustion is stopped, and a filter is installed in the vaporizer to capture tar. Furthermore, in order to be able to replace this filter, a method has been adopted in which the inside of the vaporizer is constructed with a double pipe structure and the filter is inserted into the inner pipe.

However, the double-tube structure vaporizer described above has the following problems. In other words, to make it easier to replace the tar when it becomes clogged, the vaporizer has a double-tube structure, and the inner and outer tubes are sealed to create a low-temperature area. This sometimes causes so-called pulsating combustion in which the flame fluctuates during combustion, especially during weak combustion with a low combustion amount. In order to increase the durability of the sealing material, a low-temperature non-heated part is formed and the seal is performed in that part, but after high-temperature steam flows into this low-temperature part, condensation occurs and accumulates. This is caused by flowing to high temperature areas and causing bumping. When such pulsating combustion occurs, especially when the flame becomes small, the safety device detects a misfire and extinguishes the fire even though heating or hot water supply continues.

(Problems to be Solved by the Invention) As described above, the conventional liquid fuel vaporizer has the problem that pulsating combustion occurs during weak combustion, and when the pulsation is particularly large, the fire is extinguished by detection of a misfire. SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid fuel vaporizer that can form a stable flame on a burner without causing pulsating combustion even during weak combustion.

[Structure of the invention]

(Means for Solving the Problem) The present invention includes a first vaporizing pipe that is directly heated by a heater, and a first vaporizing pipe that is detachably inserted into the first vaporizing pipe with a small gap.
The second vaporizing pipe is heated indirectly through the vaporizing pipe, and each pipe has a heating part that is heated by the combustion gas and a non-heating part that is not heated, and these parts are connected to the chamber of the combustion chamber. separated by a wall. The non-heating portion has a sealed end portion and basically constitutes a double pipe type vaporizer. In such a vaporizer, the present invention provides a projection for suppressing vaporized gas from flowing into the non-heating space formed by the first vaporizing pipe and the second vaporizing pipe, or for suppressing rapid expansion during bumping. It is characterized by having a section, a constricted section, or a stepped section.

(Function) With this configuration, the flow of fuel vapor to the low temperature region of the non-heating part is suppressed during weak combustion, reducing the amount of condensation per hour and preventing bumping in the non-heating part. However, the projections or constrictions do not act as flow resistance and cause large fluctuations in the amount of steam flowing into the nozzle. Therefore, pulsating combustion can be reliably suppressed while maintaining the durability of the seal portion.

(Example) Examples of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a partially cutaway perspective view of a heating device incorporating the liquid fuel device of the present invention.

In FIG. 1, reference numeral 1 denotes a housing housing a combustion chamber 2, and on the back side of the combustion chamber 2, a blower (not shown) for indoor air circulation is held in the housing 1.
This combustion chamber 2 houses a Bunsen burner 3 and a liquid fuel vaporizer 4, which will be described later. A liquid fuel vaporizer 4 is held on the side wall of the combustion chamber 2.

FIG. 2 is a cross-sectional view showing one embodiment of the vaporizer 4 for a liquid fuel combustion device of the present invention. That is,
In FIG. 2, reference numeral 11 denotes an outer tube constituting the first vaporizing pipe, and a certain minute space 13 is formed inside this outer tube.
An inner pipe 12 forming a second vaporizing pipe
has been inserted. The outer tube 11 and the inner tube 12 are joined by flanges 14, 14 provided at the ends protruding from the side walls of the respective combustion chambers 2 via a heat-resistant rubber seal 16 and an O-ring 17, such as screws (not shown) or the like. It is joined with. Reference numeral 18 denotes a heater for heating the outer tube 11, and the heater 18 is fixedly attached to the outer tube 11 by an aluminum layer 19. A filter 20 for capturing tar is inserted into the inner tube 12 to prevent tar from flowing out to the nozzle. The liquid fuel flows from the fuel supply pipe 21 into the inner pipe 12 via the header 22 that seals the inner end of the combustion chamber 2 of the outer pipe 11 and the inner pipe 12. Since the fitting of the tube 12 is loose, the liquid actually flows into the inner wall surface of the outer tube 11.

Reference numeral 23 is an outlet for vaporized gas and communicates with a nozzle 24 . 25 and 26 are protrusions provided close to the heating part side of the non-heating part 27 of the outer tube 11 and the inner tube 12, respectively, and in this embodiment, the protrusions 25 and 2 are
6 come into contact with each other to form a seal when the inner tube 12 is inserted.

The protrusions 25 and 26 may be provided on at least one of the inner tube 12 and the outer tube 11, or the minute space 13 is divided into a heating side and a non-heating side without forming the protrusions 25 and 26. A configuration with a ring interposed may also be used. The divided portions are the heating side space 13a and the non-heating side space 13.
It is not necessary to have a structure that completely seals b, but it may be a structure that resists the flow of gas.

28 is a thermistor provided near the nozzle 24 for adjusting the vaporizer temperature.

Next, the operation of the vaporizer configured as described above will be explained.

First, when heating (or hot water supply) operation is started, the outer tube 11 is heated by the heater 18, and the temperature of the inner tube 12 also begins to rise via the minute space 13a. When the wall temperature of the outer tube 11 and the inner tube 12 rises to a temperature sufficient to vaporize the liquid fuel, the thermistor 28 provided near the nozzle 24 detects this state and drives the fuel pump (not shown). . The liquid fuel sent from the fuel pump flows from the fuel supply pipe 21 at the left end of the vaporizer through the header 22 into the inner pipe 12 and is vaporized. The liquid flows into the outer tube 11 and is vaporized. The tar contained in the vaporized gas is filtered through the filter 20.
The vaporized gas is ejected through the small hole of the nozzle 14 into the throat of the Bunsen burner 3 through the vaporized gas outlet 13, premixed in the mixing tube while drawing in the surrounding air, and ignited this air-fuel mixture. Start combustion.

At this time, the fuel gas generated in the heating region flows toward the vaporized gas outlet 23, and a part of it flows into the space 13b and is accumulated in the space 13b while being condensed in the lower temperature part. The condensed fuel stored in the space 13b as time passes,
A liquid phase is formed from the lower temperature side of the flanges 14 and 15 toward the higher temperature heating side, and the degree of superheating increases, causing bumping in the high temperature part. As a result, the pressure inside the vaporizer increases rapidly, causing the nozzle 24
A large amount of vaporized gas is temporarily blown out. On the other hand, after a large amount of vaporized gas is temporarily blown out from the nozzle 24, the pressure inside the vaporizer drops rapidly, the supply of vaporized gas to the burner (not shown) is almost completely exhausted, and the flame on the burner also goes out. That's the situation.

This is the cause of pulsating combustion, which has been a problem in the past, but in this embodiment, a space is formed between the inner and outer tubes 11 and 12 in the non-heating part 27 near the vaporized gas outlet 23. Since the projecting pipe parts 26 and 25 are provided around the entire circumference so as to block the heating part 13b and the projecting parts 25 and 26 are in contact with each other, the low temperature of the non-heating part 27 is removed from the heating part space 13a and the vaporized gas outlet 23. It is difficult for the vaporized gas to enter the space 13b, and even if the sealing by the protrusions 25 and 26 is not complete, the inflow amount becomes considerably small because the flow resistance is considerable in those parts. Furthermore, even if the fuel liquid accumulates in the low temperature space 13b and bumping occurs, the large flow resistance of the protrusions 25 and 26 suppresses a sudden increase in pressure.
4, the amount of vaporized gas blown out is stabilized, and as a result, pulsating combustion can be reduced.

Note that the flow resistance for reducing the inflow of steam into the non-heating space formed by the double pipe or for mitigating the sudden rise in pressure due to bumping is not limited to the protrusions caused by the throttle in this embodiment, but is also used in the low-temperature space 13b. A heat-resistant material may be provided inside the inner tube, and modifications such as wrapping a heat-resistant material around the inner tube may be made without departing from the gist of the present invention.

〔Effect of the invention〕

As described above, according to the present invention, although it has a simple configuration, rapid pressure fluctuations in the vaporizer can be suppressed to an extremely low level, resulting in stable combustion that suppresses pulsating combustion during weak combustion. It is possible to provide a liquid fuel vaporization device that forms a liquid fuel.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a heating device incorporating a liquid fuel combustion device of the present invention, and FIG. 2 is a sectional view showing a liquid fuel vaporization device according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 11... Outer tube, 12... Inner tube, 13... Vaporized gas flow space, 18... Heater, 23... Vaporized gas outlet, 24... Nozzle, 25, 26... Outer tube, inner tube protrusion Department.

Claims (1)

[Claims] 1. Double pipe structure consisting of a region heated by combustion gas and an inner pipe into which liquid fuel is supplied, which is inserted and held by forming a space inside an outer pipe whose non-heated region is partitioned and held by the combustion chamber wall. In the liquid fuel combustion device equipped with the liquid fuel vaporization device, the inner pipe communicates with a space on the side of the heated region of the outer pipe and forms a space that is substantially separated from the space on the side of the non-heated region. A liquid fuel combustion device characterized by: