JPH0642711A - Evaporation type burner - Google Patents

Abstract

PURPOSE:To shorten a flame spread time at the time of ignition and reduce the generation of white smoke even in the case where heavy oil is used as fuel. CONSTITUTION:Multiple injection holes 48 are formed in a mixing tube 44 for making fuel-air mixed gas by mixing gasified fuel from a fuel absorber 32 with combustion air, and the mixing tube 44 is projected into a combustion chamber 42. A shaft 60 and a plate 72 movable along said shaft 60 are provided in the mixing tube 44. The plate 72 is biased by a secondary coiled spring 70 in a direction in which the inner length of the mixing tube 44 is shortened. At the top end of the shaft 60, a thermally deformable member 66 is provided, which causes the plate 72 to move in a direction in which the inner length of the mixing tube 44 is made longer against the force of the secondary coiled spring 70 when a combustion temperature reaches a level at the time of stationary combustion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporative burner used for a heating device such as a vehicle heater, a ship heater, a general-purpose portable heater and the like.

[0002]

2. Description of the Related Art Generally, for example, Japanese Unexamined Patent Application Publication No. Sho 5-
Evaporative burners for heating vehicles and ships, such as that shown in No. 9-60109, are provided. In this evaporative burner, a combustion chamber is formed inside a tubular body, and a fuel absorber is arranged directly in the combustion chamber, or a fuel absorber is provided facing the combustion chamber, and the heat inside the combustion chamber is reduced. To vaporize the fuel from the fuel absorber to produce fuel vapor. On the other hand, an inflow hole for combustion air is formed on the wall surface of the body, the combustion air from the inflow hole and the fuel vapor generated from the fuel absorber are mixed in the fuel chamber, and the fuel vapor and the combustion air are mixed. Ignite the mixture with a spark plug. In the conventional evaporative burner, the fuel vapor and the combustion air are configured to flow into the combustion chamber from different positions. For this reason, it is difficult to completely mix the fuel vapor and the combustion air, and it is also difficult to set the inflow hole for the combustion air, so that there is a problem that good combustion cannot be obtained. Further, since the fuel absorber is arranged in the combustion chamber, over time, products of combustion are deposited on the fuel absorber, evaporation from the fuel absorber is impaired, and combustion failure occurs. It was easy to occur.

[0003]

In order to solve this drawback, the fuel absorber is provided in the combustion chamber with most of the fuel absorber covered by the support, and the fuel evaporated from the fuel absorber is supported by the support. The present inventor has considered that the product of combustion is not accumulated on the fuel absorber by discharging the flame from the outlet of the fuel cell to the air passage where the flame does not reach directly. In this case,
The combustion chamber is equipped with a mixing tube with a flame port for injecting a mixture of air and fuel vapor, and the mixture injected from the flame port into the combustion chamber is located near the root of the mixing tube and is parallel to the mixing tube. It is ignited by the glow plug placed in. The ignition of the air-fuel mixture by the glow plug is completed by sequentially shifting the fire from the root side to the tip side of the mixing tube. When heavy oil is used as fuel, it takes more time to transfer the heat at the time of ignition than light oil. During this period, the air-fuel mixture is not ignited and is sequentially supplied into the combustion chamber, and the air-fuel mixture becomes white smoke and fills the combustion chamber.

The present invention has been made in view of the above points, and makes it possible to adjust the length of a mixing pipe provided with a flame port for injecting an air-fuel mixture according to temperature, thereby promoting ignition and at the time of ignition. It is an object of the present invention to provide an evaporative burner capable of significantly reducing the amount of white smoke generated in

[0005]

In order to achieve the above-mentioned object, the present invention vaporizes the fuel contained in the fuel absorber and mixes the vaporized fuel with combustion air to form a mixture.
In an evaporative burner for igniting the air-fuel mixture with a spark plug in a combustion chamber provided inside a tubular body, the fuel absorber is housed inside without being directly exposed to the combustion chamber. A support provided in the combustion chamber, a fuel supply pipe that penetrates the support and opens into the fuel absorber, a fuel that projects into the combustion chamber and is vaporized in the fuel absorber, and combustion air. A mixing tube for mixing and mixing with each other to form an air-fuel mixture, and a large number of injection holes formed in the mixing tube projecting into the combustion chamber to connect the inside of the mixing tube with the combustion chamber, A plate movably provided in the tube for determining the tube length, a spring provided in the mixing tube for urging the plate in a direction to shorten the tube length, and a plate provided in the mixing tube. It has a thermal deformation member that expands and pushes the plate when the temperature becomes equal to or higher than the temperature, holds the plate at a position where the inner length of the mixing pipe is shortened by the spring at the time of ignition, and thermally deforms at the time of steady combustion after ignition. The member extends to push the plate against the spring to increase the length of the mixing tube.

[0006]

At the time of ignition, the plate is held at a predetermined position by the second coil spring so that the inner length of the mixing tube becomes short. As a result, only the injection hole of the mixing tube near the glow plug is opened, the transfer time to the vaporized fuel injected into the combustion chamber is shortened, and the generation of white smoke is reduced. At the time of steady combustion, the thermal deformation member 66 expands, and the thermal deformation member 66 moves the plate against the second coil spring so that the inner length of the mixing pipe is lengthened. As a result, the length of the mixing tube becomes long, the injection holes at positions farther than the glow plug are opened, and normal combustion can be ensured.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. 1 is a sectional view showing an embodiment of an evaporative burner according to the present invention, and FIG. 2 is a sectional view taken along the line AA of FIG. Casing 1
0 and the cover 12 form an air swirl chamber 14 inside the casing 10, and the air swirl chamber 14 is formed.
An air inlet 16 is formed for introducing air into the.
The wall plate 18 constituting the casing 10 is provided with a plurality of spiral guide plates 20 on the air swirl chamber 14 side,
As shown in FIG. 2, the plurality of spiral guide plates 20 are set in such a shape that the air introduced into the air swirl chamber 14 is directed to the center of the air swirl chamber 14. A tubular portion 22 projecting to the opposite side of the guide plate 20 is integrally formed in the center of the wall plate 18, and an air passage 24 which is an internal space of the tubular portion 22 communicates with the air swirl chamber 14. The combustion air introduced from the air swirl chamber 14 into the air passage 24 is ejected from the ejection port 26 of the air passage 24.

On a surface of the wall plate 18 of the casing 10 opposite to the guide plate 20, a cylindrical body 2 having both ends open.
8 is attached via the sealing material 30. Casing 1
The zero wall plate 18 serves as one closed end surface of the body 28. An annular fuel absorber 32 is provided inside the body 28.
And a support 3 that covers both end surfaces and the outer peripheral surface of the fuel absorber 32.
4 are provided (the inner peripheral surface of the annular fuel absorber 32 is covered with a mixing pipe 48 described later). This fuel absorber 32
Is made of porous ceramic, metal, or the like, and is capable of absorbing and holding fuel therein. The support 34 is fixed to the wall plate 18 by a fixing means 36 such as a bolt with a slight gap from the wall plate 18. Its support 34
A vaporization space 38 is provided between the wall plate 18 and the wall plate 18. The axial center of the annular fuel absorber 32 or the annular support 34 and the tubular axis of the body 28 are arranged to be the same, and the tubular outer wall of the support 34 and the body 28 are arranged.
A communication passage 40, which is an annular space connected to the vaporization space 38, is provided between the cylindrical inner wall and the cylindrical inner wall. That is, the internal space of the body 28, one end of which is closed by the wall plate 18, is a combustion chamber 42 that is a main space, the communication passage 40 that communicates with the combustion chamber 42, and the vaporization space 38 that communicates with the communication passage 40.
And the vaporization space 38 is set so as not to directly face the combustion chamber 42.

A cylindrical mixing tube 44, which penetrates through the center of the support 34 and has one end smaller in diameter than the support 34, is attached to the support 34. The closed surface 45 side of the mixing pipe 44 projects into the combustion chamber 42. The mixing pipe 44 covers the inner peripheral surface of the fuel absorber 32.
That is, the annular fuel absorber 32 is closed by a part of the mixing pipe 44 and the support 34. The opening of the mixing tube 44 faces the wall plate 18, and the tip of the opening is located at the same position as the surface of the support 34 facing the wall plate 18 or slightly protruding toward the wall plate 18 side. It is set. The central axis of the mixing tube 44 is set to coincide with the central axis of the tubular portion 22 formed on the wall plate 18, and the inner diameter of the mixing tube 44 is set to be larger than the outer diameter of the tubular portion 22. Further, as shown in FIG. 1, it is desirable that the tip end opening portion of the cylindrical portion 22 does not enter the opening portion of the mixing tube 44. The mixing passage 46, which is the internal space of the mixing pipe 44,
It communicates with the vaporization space 38 through a gap between the opening of the mixing tube 44 and the tip of the tubular portion 22. The tubular portion 2
The tip opening portion of the second jet port 26 may enter into the opening portion of the mixing tube 44. The mixing pipe 44 is provided with a large number of injection holes 48, which serve as flame ports, on the outer periphery of a tubular shape protruding into the combustion chamber 42. The injection hole 48 is formed in the combustion chamber 4
It communicates with 2. A fuel discharge port 50 for connecting the fuel absorber 32 and the mixing passage 46 is formed near the opening of the mixing pipe 44. That is, the fuel absorber 32 is set to communicate with the outside of the support body 34, that is, the mixing passage 46, only through the fuel discharge port 50.

The fuel supply pipe 54 having an opening inside the fuel absorber 32 is provided with the cover 12 and the casing 1.
It is provided through 0. That is, the fuel is always supplied to the fuel absorber 32 through the fuel supply pipe 54. On the surface of the wall plate 18 opposite to the guide plate 20,
A glow plug 56 serving as an ignition plug that generates heat over its entire length is attached. The glow plug 56 penetrates the vaporization space 38, the fuel absorber 32, and the wall plate 18, and its tip projects into the combustion chamber 42. . The glow plug 56 is installed in the immediate vicinity of the mixing tube 44 and in parallel with the mixing tube 44. The cable 58 of the glow plug 56 is pulled out to the outside through the wall plate 18 of the casing 10 and the cover 12. The glow plug 56 not only functions to ignite the air-fuel mixture ejected into the combustion chamber 42, but also functions to heat the fuel absorber 32.

One end of a shaft 60 extending toward the inside of the mixing tube 44 is fixed to the closing surface 45 of the mixing tube 44. A cap 62 having a bottomed cylindrical shape is fixed to the other end of the shaft 60. That is, this shaft 60
Fixes the bottom portion 64 of the cap 62 to the tip of the shaft 60 while penetrating the inner space of the cap 62. To the bottom portion 64 of the cap 62, one ends of a coil-shaped thermal deformation member 66 and a first coil spring 68 having different diameters are fixed. The coil-shaped thermal deformation member 66 and the first coil spring 68 are both arranged so as to surround the shaft 60. One end of a second coil spring 70 extending toward the inside of the mixing tube 44 is fixed to the closed surface 45 of the mixing tube 44. The second coil spring 70 is arranged so as to surround the shaft 60.

The disk-shaped plate 72 is provided in the middle of the shaft 60 with the center thereof being inserted by the shaft 60. The plate 72 is set to be movable along the shaft 60 while being fitted to the shaft 60 by an external force. The plate 72 is pressed by the first coil spring 68 on one surface and at the second coil spring 7 on the other surface in a normal temperature state before ignition.
Pressed by 0. A stopper 74 is fixed inside the mixing tube 44 so that the plate 72 does not move toward the opening side of the mixing tube 44 any more. This stopper 74
Assuming that the effective total length of the mixing tube 44 exposed in the combustion chamber 42 is L, the fixed position of is a distance of about 1/2 L from the closed surface 45 to the fixed position of the stopper 74. The plate 72 has a first coil spring 68 and a second coil spring 70.
If only the force acts, the second coil spring 7
The spring force of 0 overcomes the spring force of the first coil spring 68 to push the plate 72 to the left in FIG. 1, and the plate 72 is brought into contact with the stopper 74.

The coil-shaped heat-deformable member 66 has a free end that expands and contracts in a linear direction in response to a change in temperature.
For example, a shape memory alloy is used as the material. The thermal deformation member 66 has a property of expanding at a predetermined steady combustion temperature and contracting at a low temperature. For example, the heat deformable member 66 is contracted until the temperature before the steady combustion after the ignition, and the free end of the heat deformable member 66 is set so as not to contact the plate 72 in contact with the stopper 74. To be done. In the contracted state of the heat deformable member 66, the length L ₁ of the mixing pipe 44 exposed in the combustion chamber 42 up to the position of the plate 72 is the effective length of the mixing pipe 44. When the inside of the mixing tube 44 reaches a steady combustion temperature, the thermal deformation member 6
6, the total length of which extends, and the thermal deformation member 66 moves the plate 72 toward the closing surface 45 side against the second coil spring 70, thereby increasing the effective length of the mixing tube 44. That is,
The effective length of the mixing tube 44 is L ₂ shown in FIG.

Next, the function of the evaporative burner will be described. The air that has entered the air swirl chamber 14 from the air introduction port 16 is swirled by the guide plate 20 and is collected in the center of the air swirl chamber 14 and then spirally formed in the air passage 24 in the tubular portion 22. Then, the air is ejected toward the mixing passage 46 in the mixing pipe 44 while maintaining the spiral shape from the ejection port 26 of the air passage 24. On the other hand, fuel is constantly supplied to the fuel absorber 32 provided in the support body 34 from the fuel supply pipe 54, and the glow plug 56 penetrating the fuel absorber 32 heats the fuel absorber 32 and the fuel is absorbed. The fuel contained in the absorber 32 is vaporized and the fuel discharge port 5
It overflows from 0 to the mixing passage 46. The vaporized fuel is discharged from the jet port 26 of the air passage 24 in the mixing pipe 44.
Is mixed with the combustion air for combustion introduced into the mixing pipe 44 from. At this time, the combustion air is swirling in the mixing passage 4
Since it is introduced into the inside of the fuel cell 6, the combustion air and the vaporized fuel are mixed well. The air-fuel mixture sufficiently mixed in the mixing pipe 44 is radially injected into the combustion chamber 42 from the injection holes 48 formed in the cylindrical portion of the mixing pipe 44. The air-fuel mixture injected into the combustion chamber 42 is immediately ignited by the glow plug 56 protruding right beside the mixing tube 44.
This mixture is burned in the combustion chamber 42 to generate combustion gas. As described above, the fuel vaporized in the fuel absorber 32 is discharged from the fuel discharge port 50 into the mixing passage 46, but since the fuel does not burn in this mixing passage 46, the combustion residue remains in the fuel absorber 32. Will not be deposited. A part of the combustion gas generated in the combustion chamber 42 is vaporized from the communication passage 40 between the tubular outer wall of the support 34 and the body 28 to the vaporization space 38.
And the high temperature combustion gas reaching the vaporization space 38 is
It is introduced into the mixing pipe 44 together with the combustion air from the ejection port 26 of the air passage 24.

A heat-deformable member 66 provided in the mixing tube 44.
For a while after ignition (until steady combustion)
Is in a contracted state. That is, the plate 72 is in contact with the stopper 74. In this state, the effective length of the mixing tube 44 is L ₁ in FIG. 1, and the injection hole 48 corresponding to the effective length of the mixing tube 44 is located near the glow plug 56. Here, when heavy oil is used as fuel, the injection hole 48 corresponding to the effective length of the mixing pipe 44 is used.
Is close to the glow plug 56, the injection hole 48 located farthest from the glow plug 56 through the combustion chamber 4
Even if the fuel is injected into the fuel cell 2, the time required for the fire to transition is short, and the amount of white smoke generated can be reduced.

When the inside of the combustion chamber 42 and the mixing tube 44 are sufficiently heated to a high temperature during steady combustion, the thermal deformation member 66 expands and resists the second coil spring 70, and then the plate 72.
Is moved to the closed surface 45 side, and the effective length of the mixing tube 44 is lengthened (FIG. 3). In this state, the glow plug 56
The vaporized fuel is also injected from the injection hole 48 located at a position distant from, but since the interior of the combustion chamber 42 and the interior of the mixing pipe 44 are sufficiently heated, vaporization is promoted even with heavy oil. , The time to transfer the fire is short and no white smoke is generated.

[0017]

As described above, according to the evaporative burner according to the present invention, at the time of ignition, the length of the mixing tube is shortened so that only the injection hole of the mixing tube located near the glow plug is opened. During steady combustion, the length of the mixing pipe is increased to open the injection hole at a position farther than the glow plug. As a result, at the time of ignition when the combustion chamber or the mixing tube is not sufficiently heated, the flame transmission can be promoted and almost no white smoke is generated. This is particularly effective when using heavy oil.

[Brief description of drawings]

FIG. 1 is a sectional view of an evaporative burner according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a sectional view of another embodiment of the evaporative burner according to the present invention.

[Explanation of symbols]

 28 Body 32 Fuel Absorber 34 Support 42 Combustion Chamber 44 Mixing Pipe 44 Mixing Passage 48 Injection Hole 54 Fuel Supply Pipe 56 Glow Plug 66 Thermal Deformation Member 70 Second Spring 72 Plate

Claims (2)

[Claims] 1. The fuel contained in the fuel absorber is vaporized,
In the evaporative burner in which the vaporized fuel is mixed with combustion air to form an air-fuel mixture, and the air-fuel mixture is ignited by a spark plug in a combustion chamber provided inside a tubular body,
A support provided inside the combustion chamber in a state where the fuel absorber is not directly exposed to the combustion chamber, and a fuel supply pipe that is inserted through the support and opens into the fuel absorber. A mixing pipe that projects into the combustion chamber and mixes the fuel vaporized in the fuel absorber with combustion air to form a mixture, and the inside of the mixing pipe and the combustion chamber A large number of injection holes formed in the mixing pipe at a portion protruding into the combustion chamber for communication, a plate movably provided in the mixing pipe for determining the length of the mixing pipe, and the inside of the mixing pipe. It has a spring for urging the plate in a direction of shortening the length, and a thermal deformation member that is provided in the mixing tube and extends when the temperature exceeds a predetermined temperature to push the plate. The plate is held at a position where the inner length of the mixing pipe is shortened, and during steady combustion after ignition, the thermal deformation member expands to push the plate against the spring and increase the inner length of the mixing pipe. An evaporative burner characterized in that 2. The evaporative burner according to claim 1, wherein the heat-deformable member is made of a shape memory alloy, and the shape memory alloy is extended in a linear direction when the temperature exceeds a predetermined temperature.