JPS6262249B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid fuel combustion device that vaporizes liquid fuel and sends it together with primary air as a premixed gas to a flame port for surface combustion.

A conventional combustion device of this type is constructed as shown in FIG. That is, a heater 2 is buried in the upper part of a bottomed vaporizing chamber 1, and a mixing plate 3 having a diaphragm shape is attached to the open surface of the heater 2.
A blower fan 5 is connected to the side circumferential wall of the vaporization chamber 1 via a blower passage 4, and a thin fuel tube 6 whose tip constitutes a nozzle is provided on the central axis of the blower passage 4 so as to face the vaporization chamber 1. There is. Further, the fuel thin tube 6 is connected to a fuel tank 8 via a fuel pump 7. A combustion cylinder 10 is provided at the upper end of the vaporization chamber 1, to which a cylindrical ring 9 is joined and a wire mesh is arranged along the periphery of the cylinder, and the upper end is closed by a closing cap 11. The inside of the combustion tube 10 forms a premixture chamber 12,
An outer cylinder 14 is arranged around the combustion tube 10 with a combustion space 13 interposed therebetween, and the upper part of the combustion space 13 is open, and the lower end is joined to the upper end of the vaporization chamber 1 and closed.

Then, the heater 2 of the vaporization chamber 1 is energized to heat the vaporization chamber 1, and then the blower fan 5 provided through the blower passage 4 is driven to send combustion air into the vaporizer chamber 1. Subsequently, the fuel pump 7 is driven to draw fuel from the fuel tank 8 and drop the fuel into the vaporization chamber 1 from the nozzle at the tip of the thin fuel tube 6. The dropped fuel becomes vaporized gas on the high-temperature wall surface, passes through the constriction part of the mixing plate 3 disposed at the top, and is mixed with combustion air while being guided to the premixing chamber 12.
The premixed mixture is jetted outward from the periphery of the combustion tube 10 on which a wire mesh is arranged, and is ignited by an igniter (not shown) in the combustion space 13 between the outer tube 14 and the combustion tube 10, forming a combustion flame on the surface of the wire mesh. It is something to do.

In this case, the wire mesh of the combustion tube 10 that forms the combustion flame has a small heat capacity, so the combustion heat generated is dissipated together with the exhaust gas, and it is cooled by the jet flow velocity of the premixed gas. Therefore, the heater 2 buried in the vaporization chamber 1 is kept energized at all times, and is heated to a high temperature in order to vaporize the liquid fuel dripping from the fuel tube 6. The state had to be maintained, which led to higher power consumption. Further, the premixed gas mixed in the vaporization chamber 1 is guided to the combustion tube 10 through the premixing chamber 12 to form a combustion flame, and the exhaust gas is passed through the combustion space 13 and released from the open end of the outer tube 14. However, the premixed gas and the exhaust gas flow in the combustion space 1 to form a coaxial flow.
3, the exhaust resistance is small, and the residence time of the exhaust gas in the combustion space 13 is short, and a sufficiently high temperature state is not maintained, resulting in incomplete combustion due to fluctuations in the air-fuel ratio balance due to cooling, and a large amount of carbon monoxide is generated. In addition, the combustion flame on the wire mesh surface is formed non-uniformly, resulting in the generation of a large amount of nitrogen oxides due to the high temperature flame due to the density of the flame, and the combustion tube 10 is deformed.

The present invention eliminates these conventional drawbacks by heating the vaporization chamber itself using the combustion heat accompanying combustion, thereby creating a high temperature state in which the liquid fuel can be sufficiently vaporized, thereby reducing the heating temperature of the heater. In addition to minimizing the energization time to achieve power savings, the exhaust gas is routed in the opposite direction to the direction in which the premixed gas is ejected from the vaporization chamber, extending the gas residence time and creating a high-temperature atmosphere that completely eliminates heat. The aim is to achieve combustion.

In order to achieve this object, the present invention connects a vaporization chamber to one end of the combustion tube, and provides an outlet for exhaust gas from the combustion space formed by the combustion tube and the outer tube near the vaporization chamber. .

With this configuration, the premixture generated in the vaporization chamber is guided to the combustion tube and forms a combustion flame on its surface, and the exhaust gas accompanied by combustion heat is discharged from the exhaust gas outlet while contacting the surface of the vaporization chamber. Therefore, the vaporization chamber is sufficiently heated by the combustion heat, and almost no current is applied to the heating heater, so that power can be saved due to thermal feedback. In addition, since the exhaust gas flows in the opposite direction to the ejection direction of the premixture, the internal pressure of the combustion space increases, the residence time of the exhaust gas becomes longer, and the combustion tube can maintain a sufficiently high temperature, allowing the combustion of the premixture. The reaction is extremely smooth and complete combustion can be achieved. Furthermore, if a primary air chamber for combustion is provided near the gas outlet by utilizing the end face of the vaporization chamber, which is kept at a high temperature, the combustion air will be heated to a high temperature before entering the vaporization chamber. The hot air is sent into the vaporization chamber, and some of the droplets ejected from the fuel tube can be vaporized in the air.
Since the amount of fuel vaporized on the high-temperature walls of the vaporization chamber can be reduced, disturbances in the air-fuel ratio due to vaporization delays that tend to occur in the vaporization cylinder are eliminated, tar formation is alleviated, and good combustion characteristics are achieved.

An embodiment of the present invention will be described below with reference to FIG.

In FIG. 2, a heater 21 is embedded inside a cylindrical vaporizing chamber 20. As shown in FIG. Further, the front end of the vaporization chamber 20 is provided with a premixture outlet 22 as a tip throttle, and the rear end is provided with a closing partition plate 2 having a convex portion and a concave portion.
There are 3. Further, an air swirling plate 25 formed with a large number of swirling vanes 24 is fitted into the partition plate 23, and the partition plate 23 and the air swirling plate 2 are fitted with a screw 26.
5 and is connected to the vaporization chamber 20. Further, by arranging the air blowing outer cylinder 27 so as to cover the closing partition plate 23 from the rear, a primary air chamber 28 is provided inside, and it is joined to the closing partition plate 23 with a screw 29 . A large number of air inlets 30 are provided around the outer periphery of the concave portion of the closing partition plate 23, and a secondary air chamber 31 is provided between the air swirling plate 25 and the air swirling plate 25. The blocking partition plate 23
The convex portion is closed and has a plurality of fuel injection ports 32 in the tangential direction of the cylinder of the convex portion, facing a premixing chamber 33 formed between the air swirling plate 25 and the vaporizing chamber 20. A ventilation passage 34 is provided on the rear surface of the ventilation outer cylinder 27.
A blower fan 35 is connected via the. Furthermore, the fuel supply pipe 36 and the fuel pipe 37 are fixed to the blower outer cylinder 27 by a connecting member 38, and the fuel pipe 37 is connected to a fuel tank 40 via a fuel pump 39. Further fuel supply pipe 36
A fuel branch pipe 41 is provided at the tip of the fuel branch pipe 41 and a plurality of fuel thin tubes 42 are provided, and these fuel thin tubes 42 are made to face the premixing chamber 33 from the fuel injection port 32 . A large cylindrical diameter part 44a of a rectifying cylinder 44 having a large number of pores 43 is joined to the front part of the vaporization chamber 20, and a heat-resistant combustion wire mesh 45 is joined to the outer periphery of the large cylindrical diameter part 44a to form a cylindrical shape. A rectifying space 46 is provided around the outer periphery of the hole 43 to constitute a combustion cylinder 47 . The combustion tube 47
An outer cylinder 49 made of a glass cylinder with heat resistance and good heat dissipation or a material with good heat absorption is provided around the outer periphery of the combustion cylinder 4 through a combustion space 48.
7 and the end faces of the combustion space 48 are closed. Then, at the end surface of the outer cylinder 49 opposite to the closed surface, the vaporization chamber 2
An outer cylinder support cylinder 51 is provided near zero. Further, this outer tube support tube 51 is provided with a plurality of exhaust gas injection holes 52 from the combustion space 48, and furthermore, the end portion is provided with a closed partition plate 2.
3, and the combustion tube 47 including the straightening tube 44, the outer tube 49, and the outer tube support tube 51 are held between the closing partition plate 23 and the closing plate 50 by a fixing screw 53 provided near the center of the closing plate 50. ing.

Next, the operation of the above configuration will be described. The heater 21 embedded in the vaporization chamber 20 is energized to heat the vaporization chamber 20 and the premixing chamber 33 to create a high temperature state in which the fuel can be vaporized. In addition, a blower fan 35 is driven through a blower passage 34 to blow combustion air into a primary air chamber 28 partitioned by a blower outer tube 27.
A portion of the high-speed airflow is narrowed through the fuel jet port 32 provided on the convex portion of the blocking partition plate 23 to direct the high-speed airflow to the premixing chamber 3.
3, and other air detours to the outer periphery through the concave portion of the blocking partition plate 23 and enters the vaporizing cylinder 2 of the blocking partition plate 23.
The air is guided to the air inlet 30 as a flow along a plane near zero, enters the secondary air chamber 31, becomes a swirling flow by the plurality of swirling vanes 24 formed in the air swirling plate 25, and is introduced into the premixing chamber 33. Ru. On the other hand, the liquid fuel sucked from the fuel tank 40 by driving the fuel pump 39 passes through the fuel pipe 37 and enters the fuel supply pipe 36 connected by the connecting member 38, and is divided into a plurality of fuel thin tubes 42 by the fuel branch pipe 41. , the liquid droplets are ejected from the tip face facing the fuel jet nozzle 32. Here, since the fuel injection port 32 has a small-diameter constricted shape, a high-speed airflow occurs, and the fuel thin tube 42
The fuel droplets are fed under pressure from the fuel pump 39, turn into fine particles, and are ejected into the premixing chamber 33 maintained at a high temperature, where they instantly vaporize and form a premixed mixture with combustion air. The premixed mixture is generated and swirled and released into the rectifying tube 44 from the jet port 22, guided into the rectifying space 46 through a large number of pores 43, and in the rectified state is passed through the combustion tube 47 formed by the combustion wire mesh 45. It becomes a thin layered flame. Then, the exhaust gas accompanied by combustion heat is changed into a reverse flow by the closing plate 50, and is radiated to the outside from the combustion gas jet port 52 of the outer cylinder support tube 51 located near the vaporization chamber 20.

In this way, the premixture generated in the premixing chamber 33 of the vaporization chamber 20 is ejected from the pores 43 of the straightening tube 44 in a well-balanced manner, and in order to maintain a stable jetting speed in the straightening space 46, the combustion wire mesh 45 is Aims to make the combustion flame uniform, eliminate dark and light areas of the flame, make heat distribution uniform, prevent thermal deformation of the combustion wire mesh 45, and reduce the generation of nitrogen oxides due to high-temperature flames and carbon monoxide from cooling parts. In addition, by causing the exhaust gas to flow back in the direction opposite to the direction in which the premixture is ejected, the exhaust resistance within the combustion space 48 is increased, the exhaust gas residence time is lengthened, and the atmospheric temperature is maintained in a high temperature range.
The combustion reaction can be completed in a short time on the surface. moreover,
In order to guide the exhaust gas in the opposite direction and dissipate it from the combustion gas outlet 52 along the vaporization chamber 20,
Heat feedback to the vaporization chamber 20 can be sufficiently performed. In addition, since the exhaust gas is guided to the combustion gas outlet 52 along the end face of the closing partition plate 23 fixed to the vaporization chamber 20, the combustion air introduced into the primary air chamber 28 provided on the opposite face is heated to a high temperature. In this state, the air passes through the secondary air chamber 31 and enters the premixing chamber 33. Therefore, the vaporization of the fuel droplets from the fuel thin tube 42 can be promoted.

As described above, according to the liquid fuel combustion device of the present invention, combustion on the surface of the combustion cylinder can be maintained in a high temperature range, the combustion reaction can be completed in a short time, and complete combustion can be achieved.
Furthermore, the amount of heat of the exhaust gas is sufficiently fed back to the vaporization chamber, so that the power supply to the heating heater can be significantly reduced except during preheating before ignition.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional liquid fuel combustion device, and FIG. 2 is a sectional view of a liquid fuel combustion device according to an embodiment of the present invention. 20... Vaporization chamber, 43... Pore, 44... Rectifying cylinder, 45... Combustion wire mesh, 46... Rectifying space, 47
... Combustion cylinder, 48 ... Combustion space, 49 ... Outer cylinder,
50...Closing plate, 52...Combustion gas outlet.

Claims (1)

[Claims] 1. A rectifier cylinder having a large number of pores, a combustion cylinder provided around the rectifier cylinder through a rectification space, connected to one end of the combustion cylinder, and equipped with a combustion air supply means and a fuel supply means. Equipped with a vaporization chamber,
The other end of the combustion tube is closed with a closing plate, and an outer cylinder is provided around the combustion tube through a combustion space whose other end is closed with the closing plate, and the combustion space is provided near the vaporization chamber. A liquid fuel combustion device equipped with an exhaust gas outlet.