JPS582337B2 - pilot burner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pipe burner in a combustion appliance such as a gas water heater.

In addition to the basic function of transferring fire to the main burner, such a pie mouth burner also has the function of activating a safety device that stops fuel supply to the main burner in response to a decrease in indoor oxygen concentration. There are many.

That is, when the indoor oxygen concentration decreases due to insufficient ventilation, etc., the fire extinguishing safety device is activated by utilizing the fact that the pilot burner's combustion flame lifts faster than the main burner. The pipe burner of 2005 was configured to utilize the flame lift characteristics of its main flame hole (generally about 3 to 4 mm in diameter) itself, so its oxygen deficiency detection characteristics were not sufficient, and it could only be applied to natural combustion. This was limited to fuel gases with a slow combustion rate, such as gas and LPG.

In other words, although the input of the pie-cut burner is small and it is more likely to cause lift due to lack of oxygen than the main burner, it still maintains the essential function of the pie-cut burner, which is the ability to transfer fire to the main burner. Because of the necessity, there is naturally a limit to the reduction of the flame hole area of a pie mouth burner, and it cannot be reduced unnecessarily.

For this reason, it is not possible to make the flame lift characteristics due to oxygen deficiency sufficiently sensitive, and especially when targeting fuel gas with a high combustion rate such as coal-based gas, In order to ensure the transfer function, the flame hole had to be made relatively large, and it was practically impossible to design a flame hole that could cause flame lift due to lack of oxygen.

In order to solve such conventional problems, the present inventor set the flame hole diameters to various sizes and conducted a number of experiments to examine the influence of the flame hole area and the oxygen concentration in the combustion air on the stability of the combustion flame. After repeated experiments, we obtained the results shown in Figure 1.

The diagram shown in the figure shows the boundary velocity gradient on the vertical axis and the volume ratio (air/gas) of air and gas (CH4 was used in this experiment) on the horizontal axis. 02
02 is 21%) and oxygen deficiency (02 is 19%).

As is clear from the figure, the tiny flame holes of 1 to 2 mmφ exhibit unique characteristics when oxygen is depleted, and it has been discovered that lift characteristics that are extremely sensitive to oxygen depletion can be obtained.

The present invention was developed based on such knowledge, and its purpose is to sufficiently secure the function of transferring the pilot flame to the main burner, while also obtaining lift characteristics that are sensitive to oxygen deficiency. Therefore, the object of the present invention is to construct a pipe-cut burner as a single burner that can prevent troubles caused by oxygen deficiency and ensure combustion safety even when the target is a gas with a high combustion rate. .

In order to achieve such an object, the pie tip burner according to the present invention has a slit-shaped or The present invention is characterized in that small auxiliary flame holes are provided in a row toward the main flame hole, and a flame lift detector is provided at a location facing the small auxiliary flame holes.

In other words, according to the above configuration, two types of flame holes are provided in a single burner body, and although the burner is a single burner, the original function of a pie mouth burner, which is the transfer of flame to the main burner, is While ensuring that the combustion is carried out with a stable combustion flame in the main flame hole having a relatively large opening area,
By making the auxiliary flame hole narrower than the main flame hole and having a smaller opening area, the resulting flame lifts extremely sensitively as the oxygen concentration decreases as described above.
Even if the target gas is a gas with a higher combustion rate than natural gas or LPG, it is possible to reliably detect flame lift due to a decrease in oxygen concentration, and it is possible to detect flame lift caused by oxygen deficiency. It is possible to effectively prevent such troubles and ensure combustion safety.

In addition, in order to detect flame lift due to lack of oxygen using the auxiliary flame hole installed separately from the main flame hole and the flame lift detection device installed opposite the main flame hole, a target is installed just in front of the main flame hole. Therefore, even if the flame transfer function to the main burner, which is the original function of the pie mouth burner, is improved, the flame lift detection due to the decrease in oxygen concentration can be reliably performed without being adversely affected. effective.

Furthermore, because the small auxiliary flame holes are formed narrower than the main flame hole, it would normally be difficult to ignite the auxiliary flame holes, but this According to the invention, by configuring the small auxiliary flame holes in the form of slits that are continuous with the main flame hole or in a row toward the main flame hole, the flame can be easily flowed from the main flame hole to the auxiliary flame hole. Since the transfer is made as high as possible, there is no such difficulty in ignition, and ignition at the time of ignition, as well as re-ignition after unexpected extinguishing due to factors other than lack of oxygen, such as wind, are prevented.
This made it extremely easy and quick to do so.

Hereinafter, embodiments of the present invention will be described based on illustrative drawings.

Figure 2 I to H show a pie mouth burner to which the present invention is applied;
A main flame hole 1a is formed at the tip of the pie mouth burner body A, and the main flame hole 1a has a relatively large hole diameter that is sufficient to ensure a sufficient flame transfer function to the main burner (not shown). One side wall has a width l1 narrower than the main flame hole.
(City gas classification 6C gas depending on combustibility is approximately 0.3 to 0.
It is set to about 0.5 to 1 mm for 5 mm, 13 A, etc.

) with a suitable length l2 is formed in a state that is connected to the main flame hole 1a, and is located at a position opposite to the auxiliary flame hole 1b, and is located at a position opposite to the main flame hole 1a. Elements such as thermocouples and flame rods, which serve as the flame lift detector 2 of the fire extinguishing safety device, are arranged at positions that are not directly affected by the flame that controls the transfer of fire to the main burner.

The slit width l1 of the auxiliary flame hole 1b greatly influences the determination of the oxygen deficiency lift point, so in addition to increasing the dimensional accuracy, if necessary, by interposing a spacer = 3, etc., it is possible to Slit width l1 due to deformation and thermal expansion
Prevent changes in

In addition, since it affects the stability of the flame in the auxiliary flame hole 1b and the heat resistance of the area around the auxiliary flame hole 1b, it is necessary to move both sides of the auxiliary flame hole 1b from the tip of the burner beyond the upstream end of the auxiliary flame hole 1b. It is desirable to scrape it off to the desired position and form thin rising walls 1b', 1b' on both sides of the auxiliary flame hole 1b.

According to the above configuration, the air/fuel gas mixture (stoichiometric air-fuel ratio 3) is mixed by the Bunsen method or other suitable method.
0 to 60%) is supplied, a flame that controls the flame transfer to the main burner is formed in the main flame hole 1a, and a flame is formed in the auxiliary flame hole 1a.
A portion of the flame also ejects from b to form an auxiliary flame.

The flame lift detector 2 detects this auxiliary flame and keeps open a solenoid valve (not shown) installed in the fuel gas supply system to the pipette burner and the main burner to continue combustion.

When the oxygen concentration in the combustion air decreases due to insufficient ventilation, the auxiliary flame lifts. This is detected by the flame lift detector 2, the solenoid valve is de-energized, and both burners are extinguished.

The dimensions 11 and 12 of the auxiliary flame hole 1b and the air-fuel ratio vary depending on the oxygen concentration at which the auxiliary flame is to be lifted, the mounting direction of the pipe burner, and the type of fuel gas, so they are set appropriately as necessary.

FIGS. 3A to 3C show another embodiment, in which the auxiliary flame hole 1b is constituted by a row of minute circular holes arranged in parallel toward the main flame hole 1a.

1c is a slit for ensuring fire transfer from the main flame hole 1a to the auxiliary flame hole 1b.

The rest of the structure is the same as in the previous embodiment, so a description thereof will be omitted.

FIGS. 4A to 4C show yet another embodiment, in which a slit of the same width is provided across the tip of the pie mouth burner body A and a portion located diametrically opposite, and a part of the slit is formed into an auxiliary flame hole.
b, and the remaining part constitutes the main flame hole 1a.

[Brief explanation of drawings]

The drawings illustrate an embodiment of the pie-mouth burner according to the present invention, and FIG. 1 is a diagram showing the influence of flame hole area and oxygen concentration on flame stability, and FIG. Figure 2 shows a plan view, Figure 2 C shows a front view, Figure 2 2 shows a sectional view taken along line 2-12 in Figure 2 A, and the second figure shows a Hoho sectional view in Figure 2 A. Figure 3 A is a longitudinal cross-sectional side view of the main part;
The figure opening is a plan view, Figure 3C is a sectional view taken along the H-Ha line in Figure 3A,
Figures 4A, 4C, and 4C show another embodiment, Figure 4A is a vertical sectional side view of the main part, Figure 4A is a plan view, and Figure 4C is a sectional view taken along the line H-H of Figure 4A. It is. A...Pie mouth burner body, 1a...
・Main flame hole, 1b...Auxiliary flame hole, 2...
Flame lift detector.

Claims (1)

[Claims] 1 Near the main flame hole 1a of the pie mouth burner body A, a slit-shaped slit that is narrower than the main flame hole 1a and continuous with the main flame hole 1a, or a row facing the main flame hole 1a. A pie mouth burner characterized in that a small auxiliary flame hole 1b is provided, and a flame lift detector 2 is provided at a location facing the small auxiliary flame hole 1b.