JPH01150706A - Burner for liquid fuel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a liquid fuel combustion device in a wide range of R ranges, from household kerosene stoves to industrial furnaces.

(Prior Art) Combustion of liquid fuel includes combustion for the purpose of heating as in a stove, combustion for heating a heated object, and combustion as a power generating engine such as an internal combustion engine.

Conventional combustion methods include either directly vaporizing liquid fuel and combusting it, or splitting the liquid fuel into fine mist using an atomizer and then combusting it.

The former type of direct vaporization combustion is widely used in general household petroleum gas stoves, including the pot type (Japanese Utility Model Publication No. 58-35713) and the wick type (Japanese Unexamined Utility Model Publication No. 58-203307, Japanese Unexamined Patent Application Publication No. 1988-60).
64134 publications) or vaporization type (JIS 3
030).

The pot type uses an evaporating dish to evaporate and burn the fuel, and the evaporating part and burning part are integrated.

In the wick type, a wick of asbestos or other material inserted into the fuel tank absorbs the fuel and its surface area is expanded so that it can easily evaporate. When ignited, the flame spreads to the core and continues combustion.

Further, the vaporization type is a method in which the fuel is evaporated in a vaporization chamber or a vaporization tube and then burned in a combustion section, and the vaporization section and the combustion section are separated.

On the other hand, spray combustion is used in some domestic kerosene stoves, but in many other cases, it is also used in industrial furnace boilers. This method increases the contact area and promotes evaporation and combustion reactions.

The oil burner used in -m is a rotary burner, a jet burner (steam spray, air spray, mechanical spray M), a special burner (gun type high pressure spray, low pressure spray N), etc. There are also examples of a kind of ignition device in which liquid fuel is turned into foam and ignited by an electric spark (Japanese Patent Publication No. 49-42018, Japanese Patent Application Laid-Open No. 47-38368).
Publication No.).

(Problems to be Solved by the Invention) With combustion methods such as the pot type that directly vaporizes liquid fuel, it is difficult to rapidly increase combustion until the combustion chamber is sufficiently warmed after ignition. etc., it takes quite a while for it to get warm after ignition. In addition, combustion methods such as the wick type have a narrow range in which the amount of combustion can be varied, making it impossible to always provide comfortable warmth depending on the outside air conditions and the size of the room.

Furthermore, it is a well-known fact that there is a perception that kerosene stoves are smelly, as the smells produced when igniting or extinguishing are unbearable.

In particular, the odor during digestion must be eliminated quickly for reasons of safety (for example, JIS stipulates that if a device is accidentally knocked over due to vibrations such as an earthquake, it must be removed within 10 seconds. As a reaction to this, the fact is that the smell of digestion tends to become stronger.

This means that the flame disappears as quickly as possible after the extinguishing operation. For example, in the case of a kerosene stove, even after the extinguishment, fuel vapor evaporates from the wick and boiler, and it passes through the still hot combustion cylinder. When doing so, it oxidizes to aldehydes, etc., which have a pungent odor, resulting in a strong odor and causing discomfort.

On the other hand, although there are many types of combustors for the spray combustion method, in all of them, when oil droplets are sprayed together with air, the oil droplets have a wide particle size distribution, and each particle interacts with each other. Move in different directions and at different speeds.

Therefore, spray combustion lacks uniformity, and oil droplets reach the front of the flame and are surrounded by a diffusion flame without sufficient evaporation and mixing processes, which tends to create an uneven flame. There are problems such as the tendency to cause local overheating.

In addition, equipment for spraying oil is required, which has the disadvantage of increasing running costs such as power costs.

Japanese Patent Publication No. 49-42018 and Japanese Patent Publication No. 47-3836
The example presented in Publication No. 8 functions as an ignition device, and cannot be used as a means to stably perform continuous combustion.

(Means for Solving the Problems) The present invention expands the range of variable combustion amount of liquid fuel, prevents odors during ignition and extinguishing, and improves uneven spray flames by converting liquid combustion into foam. This provides a combustor that allows continuous combustion.

Here, the foam refers to an aggregate of bubbles surrounding a gas such as air or oxygen with a thin film of liquid fuel. Specifically, it is obtained by blowing gas such as air into liquid fuel such as kerosene, and also includes those obtained by adding a foaming agent to promote foaming.

A noteworthy characteristic of this foam combustion is that it is possible to increase the contact area between the fuel and air, which is different from conventional methods, and promotes evaporation and combustion reactions.

The present invention is a combustion device that stably burns such foamed fuel and expands the variable range of combustion amount.

FIG. 1 is a sectional view showing the structure of the present invention, and FIG. 2 is a plan view.

In the figure, 1 is a combustor, 2 is a bubble collector, 3 is an orifice,
Reference numeral 4 indicates a foam generator, and reference numeral 5 indicates a porous element. A fuel supply pipe 6 for supplying liquid fuel from the outside is connected to the foam generator 4.

On the other hand, a porous element 5 is installed inside the foam generator 4, and a foaming air supply pipe 7 is connected thereto so that gas such as air can be supplied from the outside. 8 is a secondary air supply pipe for combustion, and 9 is a secondary air supply hole.

The combustor 1 has an orifice 3 at the bottom, a cylindrical or rectangular side portion, and has a large number of secondary air supply holes 9.

Therefore, the foamed fuel reaches the orifice 3 from the bubble collecting tube 2, and is supplied to the combustor 1 through the opening IO,
It is easily combusted by the air contained in the bubbles of the foam and the air supplied from the secondary air supply hole 9, and a flame is formed upward.

FIG. 3 shows the combustion state of the liquid fuel according to the present invention.

h is the rising height of the foam. 11 is fuel, 12 is air for foaming, and 13 is secondary air for combustion.

The porous element 5 is made of sintered metal, porous ceramics, or the like. The fuel supplied to the foam generator 4 is easily foamed by the fine airflow ejected from the porous element 5.

The combustor 1 is integrally formed in the upper part of the bubble collection cylinder 2 via the orifice 3, but it may be divided into parts.

-a, the foaming ratio (foam Mi/volume of liquid fuel) of foam obtained only with liquid fuel such as kerosene is approximately 5 to 50.
It's double. On the other hand, in order to achieve complete combustion using only the air (oxygen) in the foam, the foaming ratio must be approximately 9000 times (
In the case of oxygen, 1900 times) is required.

Therefore, combustion air 13 is required in addition to foaming air 12 for foam combustion. This combustion air 13 is supplied from a secondary air supply pipe 8 and discharged from a hole 9 attached to the side of the combustor 1 to completely burn the fuel. 14 indicates the combustion flame generated.

When the foam 2' in the foam collection tube 2 connected to the combustor 1 receives radiant heat from the combustion flame 14, defoaming is promoted, and the particle size and mntit thickness of the foam become non-uniform, causing pulsating combustion. .

The present invention provides an orifice (throttle mechanism) 3 between the combustor 1 and the bubble collector 2 to suppress direct radiation from the flame 14 generated in the combustor 1 into the bubble collector 2. It is. Therefore, defoaming of the foam 2' is suppressed to a minimum, and stable combustion continues.

In addition, it is desirable that the orifice 3 has a cup-like shape that expands conically in the direction of the combustor 1. By doing so, the area that acts on the evaporation of foam can be varied, and it can function as a device for varying the amount of evaporation. be able to. Reference numeral 15 indicates an evaporation amount variable function section.

By changing the flow rate of the foaming air 12 to control the rising height h of the foam, and by changing the evaporation area of the foam 2', the amount of combustion can be freely controlled. This has greatly improved the combustion variable control range.

FIG. 4 shows another embodiment of the present invention, in which the structure of the variable evaporation function part 15 installed in the combustor l and having a conical spread is configured in a step-like manner as shown in the steps 15aS15b%15C. It is.

Therefore, this embodiment is suitable for controlling combustion by dividing the combustion amount into three stages. Note that the number of stages is not limited to this. In the 0 stages 15a, 15b and 15C, there are portions that extend vertically and do not change in cross-sectional area, and the foam rising height h may vary due to fluctuations in the foaming air I2 or other factors.
Even if the amount changes somewhat, if the evaporation area of each bubble changes within the same vertical section, the amount of combustion remains almost constant. Therefore,
Suitable for controlling combustion load in several stages.

Note that the orifice 3 may have a structure in which the orifice 3 is simply constricted by a single plate, but in that case, the influence of the radiant heat from the combustion flame 14 is large, and it may be better to raise the temperature of the orifice 3 to a certain extent. Set as appropriate depending on the properties of the fuel, etc.

Generally, radiant heat transfer (temporal radiation) into the bubble collecting tube 2 has a small effect but promotes defoaming. Therefore, in the first embodiment of the present invention, the orifice structure is cup-shaped to form a constricted part. However, the outside of the maximum constriction part is cooled with air or the like to suppress indirect radiant heat transfer into the bubble collecting tube 2.

(Effects of the Invention) As explained in detail above, the present invention is a combustor that burns liquid fuel by turning it into foam, which is easier to ignite without using a wick, compared to the conventional direct vaporization method. In addition to the unique advantages of foam combustion, such as being able to ignite and easily controlling the amount of combustion immediately after ignition, it also stabilizes combustion and expands the variable range of combustion amount, greatly improving the range of applications. It is something.

Furthermore, the generation of odor during ignition and extinguishing is also significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing the structure of the present invention, FIG. 2 is a plan view, FIG. 3 is an explanatory diagram illustrating the combustion state according to the present invention, and FIG. 4 is an explanatory diagram showing another embodiment of the present invention. It is a diagram. 1: Combustor, 2: Foam collector, 3 Niorifice, 4: Foam generator, 5: Porous element, 9:
Secondary air supply hole, 10: Open hole, 15 2 Evaporation amount variable function section. Agent Patent Attorney Tatsuo Chanoki

Claims (4)

[Claims] (1) In a device that foams and burns liquid fuel,
A liquid fuel combustion device characterized in that an orifice is provided between a combustor and a bubble collecting tube that sends fuel to the combustor. (2) The combustion device according to claim 1, wherein the orifice has a cup-like shape that expands conically in the direction of the combustor, and is formed to have a variable evaporation amount function. (3) The combustion device according to claim 1 or 2, wherein the orifice has a shape that widens stepwise in the direction of the combustor. (4) The combustion according to claim 1, 2, or 3, wherein the orifice shape is a cup-like or stepwise expanded shape and has a constriction so that it can be cooled from the outside. Device.