JPS6226660Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an indoor open type household combustion appliance.
A combustion device that uses a premix burner that performs surface combustion to clean combustion exhaust gas, reduce nitrogen oxides (hereinafter collectively referred to as NOx), and expand the stable combustion range to fully accommodate variable combustion volume. It is related to.

Conventional burners for household combustion appliances that are open indoors have the disadvantage that the flame temperature is extremely high due to high-load combustion using slit flame holes, and a large amount of NOx is generated. Therefore, in appliances that are used for long periods of time, such as warming-up appliances, surface combustion or other premix burners have been used to reduce NOx.

However, with a premix burner that performs surface combustion, at a certain combustion rate, a uniform planar flame is formed by surface combustion on the wire mesh, and because the flame hole area is large, the flame hole load is extremely small and the combustion flame is uniform. However, when the combustion amount is varied, the air-fuel ratio range is small, the flame becomes less uniform, and the combustion exhaust gas characteristics tend to deteriorate significantly. FIG. 2 shows a conventional surface-fired premix burner, in which numeral 1 is a gas nozzle located opposite a primary air port 2 which has a fan-shaped opening. The primary air port 2 is located at the lower side, and the burner outer cylinder 3 is provided at the upper side.The burner cylinder 4 has an opening at the upper part, and the combustion cylinder 4 is mounted inside the outer cylinder. The combustion cylinder 4 is made of a wire mesh or a punching material having pores, and is arranged around the cylinder as a flame opening to form a bottomed disc 5. A mixing chamber 6 is formed above the primary air port 2 at the bottom of the bottomed disc 5, and a premixed gas passage 7 is provided in the gap between the burner outer cylinder 3 and the combustion cylinder 4 having a flame port. With this configuration, primary air is sucked into the fan-shaped primary air port 2 under the influence of the discharge pressure of the combustion gas ejected from the gas nozzle 1, and the fuel gas and combustion air introduced into the mixing chamber 6 are mixed. The premixed gas forms a gap between the burner outer cylinder 3 and the combustion cylinder 4, is guided to the premixed gas passage 7, and is ejected to the inner surface from the flame port formed by the combustion cylinder 4. This is ignited by an igniter (not shown) to form a flame on the inner surface of the flame port. In this case, the flame port is made of a wire mesh or a punching material with many pores, so the flame hole area is very large, the load on the flame hole is small, and the flame temperature is low due to surface combustion. low
It is possible to reduce NOx. However, the air-fuel ratio tends to be disturbed due to small changes in the amount of air or the amount of combustion, and a uniform flame cannot be obtained at the flame nozzle, causing incomplete combustion locally and generating raw gas, soot, and carbon. The combustion exhaust gas characteristics deteriorate significantly. Furthermore, if the uniform flame becomes unstable, high temperature areas will occur locally, leading to an increase in NOx. When the combustion amount is varied, the air-fuel ratio balance at the cylindrical flame opening is disrupted, and on the high-calorie side, as shown in Figure 3, the pressure balance between the upper and lower sides of the flame opening increases, and This creates a turbulent state in which the ejection pressure increases and is small at the bottom, and the combustion flame at the top and bottom becomes uneven, resulting in CO
This has the disadvantage that it is almost impossible to change the combustion amount because the exhaust gas characteristics are significantly deteriorated due to the generation of gas and raw gas.

The purpose of this invention is to improve the surface combustion premix burner to achieve lower NOx levels, expand the range of stable combustion volume, enable variable combustion volume over a wide range, and achieve cleaner combustion exhaust gas. That is.

In order to achieve this purpose, the present invention has an outer cylinder placed in the upper part of the vaporization chamber, and a combustion tube separated into upper and lower parts by a ring-shaped disk inside the outer cylinder. A cylindrical shape with a larger flame diameter in the downstream combustion area than in the upstream combustion area is formed by sandwiching the ring-shaped discs, and the flame opening is made of wire mesh or punching material with many pores. The lower end of the flame nozzle is held by a bottomed disc, and the upper part of the flame nozzle in the downstream area of combustion is attached to the outer cylinder and is open on the inside. Further, a rectifying cylinder made of a wire mesh, a punching material having perforated holes, or the like is arranged with a gap around the flame port in the downstream region of the combustion, and a rectifying chamber is provided between the flame port and the rectifying cylinder.

With this configuration, the combustion cylinder forms a combustion flame while being separated into two parts with the ring-shaped disc in between. At this time, the premixture from the vaporization chamber is transported through the premixture passage between the combustion cylinder and the outer cylinder and is ejected into each flame port, but as shown in Figure 3, the ejection pressure is lower than the combustion pressure. Because the downstream area is larger, the temperature distribution between the upper and lower sides of the flame outlet surface varies, and the load on the flame outlet is particularly high in the downstream area, and it is also affected by the combustion heat from the upper combustion area of the lower part. , the temperature was extremely high, so by installing a rectifier tube around the flame nozzle in the downstream area of combustion, the ejection pressure balance between the upper and lower sides of the flame nozzle was adjusted, and the temperature distribution between the upper and lower flame nozzles was uniform. This prevents the increase in NOx caused by partial overheating, prevents flashback to the premixture due to high temperature ranges, and the generation of soot and carbon due to excess fuel, and prevents the generation of CO in areas where fuel is lean. . In addition, when the combustion amount is variable, the premixture that passes through the perforated holes of the rectifier cylinder installed around the flame nozzle in the non-combustion region is given a uniform injection speed around the entire circumference in the rectifier chamber, and when the combustion amount is large, As the ejection speed increases, the flame forming surface at the flame nozzle creates a flame with a slight lift, reducing the flame nozzle temperature and making the flame nozzle temperature uniform.When the combustion amount is small, the ejection speed decreases. The flame adheres to the flame opening, improving flame stability and preventing lift and generation of raw gas.

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

In the figure, reference numeral 10 denotes a bottomed vaporization chamber with a heater 11 installed above, and a ventilation passage 1 from the lower side wall.
It is connected to the ventilation fan 13 via 2. A fuel thin tube 14 having a nozzle formed at its tip faces into the vaporization chamber on the central axis of the ventilation passage 12, and is connected to a fuel tank 16 via a fuel pump 15.
The upper part of the vaporization chamber 10 is open as a vaporized gas outlet 17. An outer cylinder 18 is attached to the upper end surface of the vaporization chamber 10, and the upper end thereof has an opening having a smaller diameter than the outer cylinder diameter, and a combustion cylinder 19 is attached along the outer cylinder.
The combustion tube 19 has a ring-shaped disc 20 arranged near the middle, and the upper downstream combustion area is formed with a flame port 21 made of a large-diameter wire mesh, punching material with pores, etc., and the lower combustion upstream area is formed with an upper A ring-shaped disc 20 is integrally provided with a burner port 22 made of a wire mesh or a punching material having pores having a smaller diameter than the burner port 21 of the burner port 21 .
A bottomed disc 23 is joined to the lower end of the . A premixture passage 24 is provided in the space between the outer cylinder 18 and the combustion cylinder 19. A rectifying chamber 25 is formed around the combustion downstream flame port 21, and a rectifying tube 26 made of wire mesh, punching material with porous holes, or the like is installed between the chamber and the outer tube.

In this configuration, the vaporization chamber 10 is heated by the heater 1
The liquid fuel heated by 1, driven by the fuel pump 15, and sucked from the fuel tank 16 is guided to the tip of the fuel capillary 14 forming a nozzle, and is guided into the vaporization chamber 1.
0 and instantly generates vaporized gas. The combustion air that is guided to the ventilation passage 12 by driving the ventilation fan 13 flows to the vaporized gas outlet 17 together with the gas generated in the vaporization chamber 10 , and is connected to the outer cylinder 18 and the combustion cylinder 1 .
9, a part of the mixture enters the premix passage 24 formed by the ring-shaped disc, and is guided to the flame port 22 of the combustion tube 19 branched by a ring-shaped disk, and the other part is guided to the porous hole of the rectifying tube 26 arranged at the upper part. The gas is guided, enters the rectifying chamber 25, and is ejected as a rectified jet gas to the flame nozzle 21, and is ignited by an igniter (not shown) to form a combustion flame on the flame nozzle surface.

In this way, in a device that performs surface combustion by ejecting premixed gas to a flame port made of a wire mesh or a punching material having pores, a rectifying cylinder 26 is provided around the flame port in the downstream region of combustion, and a ring-shaped By combining the small diameter part and large diameter part of the flame outlet with a disc,
Evenly distributes the ejection pressure at each flame port of the premixture, eliminating variations in combustion temperature distribution between the upper and lower parts,
It prevents the generation of soot and carbon due to excess fuel and backfire combustion of the premixture in high-temperature conditions, and also prevents the generation of raw gas and CO from the lift due to lean fuel. When the combustion amount is variable, the premix introduced into the straightening tube 25 through the perforated holes of the straightening tube 26 is given a straightening effect to obtain a uniform jetting speed around the entire circumference, so when the combustion amount is large, the jetting By increasing the speed, the flame at the flame nozzle 21 is maintained in a slightly lifted state to cover the increase in heat amount due to increased combustion, and the temperature on the flame nozzle surface is lowered, so that the temperature distribution with the flame nozzle 22 at the bottom is always maintained. Keep it even. Furthermore, when the combustion amount is small, the ejection speed of the premixed gas from the rectification chamber 25 is reduced, and the flame at the flame port 21 is brought into close contact, improving flame stability and eliminating the generation of CO and raw gas due to lift. In addition, the premixed gas distribution with the lower flame port 22 is controlled by the resistor in the rectifier tube, and the flame port load is commensurate with the flame port area, so that stable combustion occurs between the upper and lower flame ports, and the flame port is always maintained. This eliminates the temperature difference and provides a uniform flame shape. In addition, by increasing the diameter of the flame port in the downstream region of combustion, the temperature of the flame port 21 does not rise due to the influence of exhaust heat and radiant heat accompanying combustion at the flame port in the upstream combustion region, and the flame temperature becomes uniform. can.

As described above, according to the combustion device of the present invention, the flame opening is divided by the ring-shaped disc, and the flame diameter is made large in the upper part and small in the lower part, and the diameter of the flame is made large in the upper part and small in the lower part. By arranging a rectifier tube, we can equalize the flame temperature and achieve low NOx, and even when the combustion amount is varied, we can equalize the flame temperature and prevent temperature rise, reducing soot, carbon, CO, and raw gas. Forms a stable combustion flame that prevents the occurrence of
It can be used as an exhaust gas screen.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a combustion device according to an embodiment of the present invention, FIG. 2 is a sectional view of a main part of a conventional combustion tube 4, and FIG. 3 is a characteristic diagram of the same device. 19... Combustion tube, 20... Ring-shaped disk, 21
...flame port, 22...flame port, 25...rectifier chamber, 26
...Rectifier tube.

Claims (1)

[Scope of utility model registration request] The combustion tube of a premix burner that performs surface combustion is formed with a combustion tube having a wire mesh or a large number of pores, and the combustion tube is separated by a ring-shaped disk to reduce the flame diameter of the combustion tube in the upstream combustion region. , the combustion tube flame diameter in the combustion downstream region is formed larger than the combustion tube flame diameter in the combustion upstream region,
A combustion device comprising a rectifying tube having a wire mesh or a large number of porous holes around the combustion tube flame port in the combustion downstream region, and a rectifying chamber provided between the flame port and the rectifying tube.