JPS6119292Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a premix combustion device.

Conventionally, there has been a device of this type as shown in FIG.

In the figure, 1 is a vaporization wall, 1A is a mixing chamber provided in the vaporization wall 1, 2 is a heater embedded in this vaporization wall 1, 3 is a dividing plate installed inside the vaporization wall 1, and 4 is a A flat ceramic combustion plate is placed on the top of the vaporization wall 1, 5 is a heat recovery surface that extends to surround the combustion plate at the top end of the vaporization wall 1, and 6 is attached to the side of the vaporization wall 1. An air nozzle, 7 is an air hose connected to the open end of the air nozzle 6, 8 is a static pressure pipe connected to the side of the air hose 7, 9 is a static pressure pipe with one end connected to the top surface, and the supplied oil is connected to the air nozzle. A constant oil level vessel (hereinafter abbreviated as OCV) for storage, 10 is an oil pipe connected to the side of OCV 9, 11 is connected to one end of the oil pipe, and is inserted into the vaporization wall 1 through the center of the air nozzle 6. It's a needle.

Next, the operation will be explained. When air is fed into the vaporization wall 1 from the air hose 7 through the air nozzle 6, a pressure difference is created between the upstream side and the downstream side of the air nozzle 6. High pressure on the upstream side is applied to the oil level in the OCV 9 which is maintained at a constant level through a static pressure pipe, and oil is supplied into the pot through an oil pipe 10 and a needle 11. At this time, the air that has been constricted by the air nozzle 6 is injected at high speed around the needle 11, so that the supplied oil is atomized and collides with the vaporization wall 1, which has been preheated to about 200° C. by the heater 2, and evaporates. The kerosene vapor mixes with the incoming air in the mixing chamber 1A, becomes uniform in flow velocity through the dividing plate 3, and is ejected from the small holes of the ceramic combustion plate 4, forming flames within or on the surface of the small holes. Burn. The heat recovery surface 5 is heated by the formed flame, and the vaporization wall 1 is heated by heat conduction, making a heater unnecessary.

The conventional premix combustion device using the flat ceramic combustion plate 4 is constructed as described above, and since the flame is cooled by the combustion plate 4, the emission of nitrogen oxides NO _x is extremely small and a large amount of radiated heat can be obtained. The director was Atsuta. However, in order to achieve stable surface heating, it is necessary to have a sufficiently large combustion surface area, which has the disadvantage that the vaporization wall 1 becomes large. Further, along with this, there were also disadvantages in that the time required to preheat the vaporization wall 1 to a certain temperature with the heater 2 became longer, and that the temperature distribution and the flame distribution on the vaporization wall 1 tended to become non-uniform. Further, when the temperature of the ceramic combustion plate 4 was lower than 750°C, the flame was cooled down and the oxidation rate of carbon monoxide CO in the exhaust gas was slowed down, resulting in a large amount of CO being emitted.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above. Therefore, a cup-shaped or cylindrical porous sintered ceramic head is provided at the opening of the mixing chamber, and the porous sintered ceramic head is By forming multiple small flame holes in the circumferential direction of the base, the vaporizing wall is made smaller, shortening the preheating time, and evening out the temperature distribution of the vaporizing wall to obtain a uniform air-fuel mixture, resulting in a uniform flame. The object is to provide a premix combustion device that can be configured.

An embodiment of this invention will be described below with reference to the drawings. In FIG. 2, the same numbers as in FIG. 1 indicate the same contents, but the shape of the vaporization wall 1, heater 2, dividing plate 3, and heat recovery surface 5 is different from the conventional one, and is cylindrical. 12 is vaporization wall 1
A cup-shaped porous sintered ceramic head is placed on top of the cup. 13 is porous sintered ceramic head 1
A tooth-shaped or hole-shaped small flame hole is opened in the circumferential direction at the lower part of the flame hole 2, and a premixed flame 14 of the small flame hole is formed by this small flame hole 13.

The operation up to flame formation is the same as the conventional one, but since the vaporization chamber 1 is cylindrical and small, mixing of vaporized fuel and air is promoted. The air-fuel mixture is rectified by the pressure equalizing plate 3, ejects from the pores and small flame holes of the porous ceramic head 12, forms a flame on the surface of the head 12, and burns. The premixed flame 14 formed in the lower small flame hole 13 collides with the heat recovery surface 5 and conducts heat, so the surface area of the heat recovery surface is required to be much smaller than the conventional one. Furthermore, since this premixed flame 14 is not subjected to the cooling effect of the porous sintered ceramic head 12, the combustion gas temperature is sufficiently high, and this high temperature gas coaxially surrounds the flame formed on the surface of the porous sintered ceramic head 12. It also promotes the oxidation of carbon monoxide (CO) in exhaust gas, reducing CO emissions.

In the above embodiment, a cup-shaped porous sintered ceramic head 12 is used, but it may also be constructed by having a cylindrical shape and closing its upper opening with a suitable material.

Furthermore, in the above embodiment, a mixture of petroleum vapor and air was sent out from the porous sintered ceramic head 12 and combusted, but the same result could be achieved using a mixture of air and a gaseous fuel such as city gas or propane gas. It is natural that combustion can be obtained.

As described above, according to this invention, a cylindrical or cup-shaped porous sintered ceramic head is provided at the opening of the mixing chamber, a plurality of small flame holes are formed in the circumferential direction of the base of the head, and each Since the structure is configured so that the heat recovery surface formed at the opening of the mixing chamber is heated by the premix flame formed by the small flame hole, the preheating time is shortened by heat transfer from the heat recovery surface heated by the premix flame. At the same time, a uniform flame can be formed in the pores or on the surface of the porous sintered ceramic head by making the vaporization wall temperature distribution uniform and obtaining a uniform mixture. Furthermore, since the premix flame 14 is not affected by the cooling effect of the porous sintered ceramic head, the temperature of the combustion gas is sufficiently high, and since this high temperature gas coaxially surrounds the flame formed on the surface of the porous sintered ceramic head, the premixed flame 14 is contained in the exhaust gas. carbon monoxide CO
It also has the effect of promoting the oxidation of carbon dioxide and reducing CO emissions.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional side view showing a premix combustion device having a conventional ceramic combustion plate, and Fig. 2 shows a premix combustion device having a cup-shaped porous sintered ceramic head, which is an embodiment of this invention. FIG. In the figure, 1A is a mixing chamber, 12 is a porous sintered ceramic head, and 13 is a small hole. In the drawings, the same reference numerals indicate corresponding parts.

Claims (1)

[Scope of utility model registration request] A cylindrical or cup-shaped porous sintered ceramic head is provided at the opening of the mixing chamber, a plurality of small flame holes are formed in the circumferential direction of the base of the porous sintered ceramic head, and a plurality of small flame holes are formed by each of the small flame holes. A premix combustion device characterized in that the heat recovery surface of the opening of the mixing chamber is heated by the premix flame.