JPS6311458Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a premix combustion device that premixes vaporized gas of liquid fuel and air and combusts the mixture.

A conventional example in which kerosene is used as fuel will be explained based on FIG. In the figure, 1 is a combustion air supply hole, 2 is a kerosene supply pipe, and the tip thereof is formed into a needle shape. 3 is an oil level regulator 4 that controls the static pressure generated in the air supply hole 1.
6 is a wall surrounding the vaporizing chamber 5 made of a material with good thermal conductivity such as aluminum, and has a throttle hole 7, a rectifying plate 8, and a flame hole plate 9 in the upper part. Reference numeral 11 denotes an ion electrode for detecting the flame 10, and a detection circuit 12 performs combustion detection. 14 is an electrode of the ceramic heater 13, and 15 is an electrically insulating plate made of alumina or the like. Further, 16 is a discharge electrode for flame ignition, 17
1 is a discharge high voltage transformer, and 18 is an orifice for setting the fuel flow rate.

Next, the operation will be explained. After electricity is supplied to the ceramic heater 13 in advance to raise the temperature of the vaporization chamber wall 6 to a predetermined temperature, combustion air is supplied into the vaporization chamber 5 through the supply hole 1 by a blower (not shown). At the same time, the static pressure in the supply hole 1 is maintained through the pressure pipe 3 by the constant oil level device 4.
An amount of fuel corresponding to the static pressure and the diameter of the orifice 18 is supplied from the fuel supply pipe 2. The supplied kerosene is atomized by the air flow ejected from the air supply hole 1, and the preheated vaporization wall 6
It vaporizes instantaneously at the top and mixes with the combustion air. This premixture is further mixed while passing through the throttle hole 7, and after the flow velocity distribution is made uniform by the straightening plate 8, it is ignited by discharge on the flame hole plate 9 by the ignition devices 16 and 17, and a stable flame 10 is generated. Form. After ignition, the vaporization wall 6 becomes a flame 10
Since it is heated by , no heater input is required. On the other hand, the detection circuit 12 constantly monitors the flame by observing the rectified waveform of the ion current flowing from the ion electrode 11, and if the flame goes out, a controller (not shown) safely stops the combustion. In the conventional device configured in this way, if the air flow rate is adjusted by changing the voltage of the blower (not shown), the static pressure inside the air supply hole 1 changes, and the fuel supply amount can be adjusted autonomously. adjusted. Therefore, the input can be adjusted with a simple operation, and a predetermined air-fuel ratio is always maintained, so stable blue flame combustion is realized. In other words, it has the advantage that the amount of harmful exhaust gases such as soot and carbon monoxide (CO) in the exhaust gas is extremely low. However, in this conventional combustion device, there were problems such as when the temperature of the combustion air decreased, it became difficult to ignite and the flame became unstable. That is, the amount of supplied air Q, the amount of fuel q, and the air ratio μ (supplied air amount/theoretical air amount) shown in FIG.
As shown in the temperature dependence characteristic diagram, the optimum air ratio μ at 20℃
(about 0.8), the air flow rate Q increases at low temperatures and conversely the fuel amount q decreases, so the air ratio μ
increases, making it difficult to ignite, and even if a flame is formed, the flame becomes unstable.

This idea was made with the aim of solving the above problems, and it uses an on-off valve (electromagnetic valve) for the pressurizing pipe passage that connects the air supply pipe and the oil level regulator and introduces the static pressure of the air into the oil level regulator. It is configured so that it can communicate with the atmosphere through an orifice, adjusts the static pressure applied to the oil level regulator according to the temperature, increases the fuel amount q at low temperatures, and suppresses the increase in the air ratio μ. This is what I did.

A conceptual diagram of an embodiment according to this invention is shown in FIG. 3, and its operation will be explained. 3' in the figure
is a pressure pipe for pressurizing the air static pressure in the supply hole 1 to the liquid level in the oil level regulator 4. One end of the pressure pipe 3a is connected to the air supply pipe, and the other end of the pressure pipe 3a is branched. The pressure pipe 3c communicates with the oil level regulator 4, and the pressure pipe 3b communicates with the atmosphere via a pipe opening/closing valve (electromagnetic valve) 19 and an orifice 20. 21 detects the ambient temperature (room temperature);
A controller that controls the pipe opening/closing valve 19 to an open state or a closed state, and the orifice 20, the solenoid valve 19, and the controller 21 constitute a static pressure adjustment device 30 applied to the liquid level of the oil level regulator 4. do. Next, its operation will be explained. After the start of preheating, the process until static pressure is applied to the leveling device 4 is carried out in the same way as in the conventional example shown in FIG. , the magnitude of the static pressure applied to the oil level regulator 4 is increased. In other words, by appropriately selecting the opening diameter of the orifice 20 and the magnitude of the static pressure applied to the oil level regulator 4 when the pipe on-off valve 19 is in the open state (ON), the air ratio μ can be optimized. value (μ ~ 0.8), and if the pipe on-off valve 19 is set to the closed state (OFF) when the ambient temperature (room temperature) is below the set temperature,
Since the escape of air from the orifice 20 is blocked, the static pressure applied to the oil level regulator increases, the amount of kerosene supplied can be increased accordingly, and μ can be prevented from becoming excessively high at low temperatures.

FIG. 4 shows the room temperature dependence characteristics of the supplied air amount Q, the fuel amount q, and the air ratio μ according to this embodiment. In addition, FIG. 4 shows the case where the set temperature for ON-OFF control of the pipe opening/closing valve is -10°C. As can be seen from this characteristic diagram, according to this invention, since the air ratio can be corrected at low temperatures, a safe combustor with good ignitability and stable flame can be obtained.

In the above embodiment, a case was described in which communication between the pressurizing pipe passage and the atmosphere was "opened and disconnected" by an on-off valve (electromagnetic valve), but as shown in FIG. 23, and the cross-sectional area of the tapered open hole 24 is increased or decreased in accordance with the height of the room temperature, thereby increasing or decreasing the static pressure applied to the liquid surface. ,
Since the feedback pressure (pressurized static pressure) can be finely adjusted, a substantially constant air ratio can always be obtained regardless of the room temperature.

Furthermore, as shown in FIG. 6, even if a thermoelement 25, in which a bellows is filled with thermowax that expands in volume when the temperature rises, is used as a driving means for the valve body 23, an almost constant air ratio can always be obtained regardless of the room temperature. Is possible.

This invention consists of a combustion air supply pipe, a fuel supply pipe that opens at the outlet of this supply pipe and is supplied with liquid fuel from an oil level regulator, and a fuel supply pipe that is connected to the liquid level in the oil level regulator in the air supply pipe. A pressurizing pipe that introduces static pressure is configured to vaporize and premix the liquid fuel and then combust it. It is characterized by being equipped with a static pressure adjustment device that decreases and increases it depending on the low temperature, and can suppress the increase in air-fuel ratio even when the temperature drops, so it has the effect of stabilizing ignition and flame. There is.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional premix combustion device;
The figure is a characteristic diagram showing the dependence of the supplied air amount, fuel amount, and air ratio on room temperature in a conventional combustion device, Figure 3 is a cross-sectional view of an embodiment of this invention, and Figure 4 is the supplied air quantity of this embodiment, Characteristic diagrams showing the dependence of fuel amount and air ratio on room temperature, and FIGS. 5 and 6 are sectional views of essential parts of other embodiments of this invention, respectively. In the figure, 1 is a combustion air supply hole, 2 is a kerosene supply pipe, 3, 3a, 3b, 3c are pressurization pipes, 4
is a constant oil level gauge, 5 is a vaporization chamber, 6 is a wall, 7 is a throttle hole,
8 is a rectifier plate, 9 is a flame hole plate, 11 is an ion electrode, 1
2 is a detection circuit, 13 is a ceramic heater, 1 is a discharge electrode, 17 is a discharge high-voltage transformer, 18 is an orifice for setting a fuel flow rate, 19 is a pipe opening/closing valve, 20 is an orifice, 21 is a controller, 22 is a bimetallic device, 2
5 is a thermowax, 23 is a valve body, 24 is an open hole, 25 is a thermoelement, and 30 is a static pressure adjusting device. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] A combustion air supply pipe, a fuel supply pipe that opens at the outlet of this supply pipe and is supplied with liquid fuel from an oil level regulator, and a static pressure in the air supply pipe that is applied to the liquid level in the oil level regulator. and a static pressure adjustment device that reduces or increases the static pressure applied in the oil level regulator in accordance with the high or low temperature of the combustion air, and vaporizes and premixes the liquid fuel. In the device configured to burn the gas after being made into a gas, the static pressure regulating device has an air escape hole to the atmosphere provided in the pressurizing pipe, and opens the escape hole when the combustion air is at a predetermined temperature or higher, A premix combustion device comprising a valve that closes when the temperature is lower than the predetermined temperature.