JPS6410723B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a pulse combustion device whose combustion structure is improved to be compatible with all types of fuel gas.

[Technical background of the invention and its problems]

Pulse combustion devices, which consume less fuel and have good combustion efficiency, are increasingly being used. This type of device has conventionally been constructed as shown in FIGS. 1 and 2, with reference numeral 1 indicating a mixing chamber having an air port 2 and a gas port, and from which a spark plug 4 is protruded; The combustion chambers are connected to each other, 6 is a tail pipe, and 7 is a decoupler, and the decoupler 7 communicates with a neutralization device (not shown) and an exhaust pipe. Further, an air supply box 8 is connected to the air port 2 via a suction pipe 8a, and inside the air supply box 8 are air holes 9.
It is partitioned off by a valve seat 10 having a diameter. A valve holder 11 is provided on this valve seat 10 with a gap in between.
An air valve 12 is interposed in between. 13 is a blower attached to the air supply box 8. Gas port 3 above
A gas supply box 14 is connected to the gas supply box 14 via a gas suction pipe 15, and the inside of the gas supply box 14 is connected to a gas hole 16.
It is partitioned off by a valve seat 17 having... A valve holder 18 is provided with a gap between the valve seat 17, and a gas valve 19 is interposed between the valve seat 17 and the valve seat 17. The gas supply box 14 also includes a gas cushion tank 2.
0, the gas solenoid valve 21, the gas governor 22, etc. are sequentially communicated.

Thus, the blower 13 is driven only at the start of combustion, the air valve 12 is opened, and combustion air is introduced into the mixing chamber 1. Further, the gas solenoid valve 21 is opened to supply combustion gas from a gas source (not shown).
This combustion gas is supplied to the gas valve 1 of the gas supply box 14.
9 is opened and the mixing chamber 1 is introduced. The ignition plug 4 is ignited when the combustion air and the fuel gas have mixed to a flammable range in the mixing chamber 1. The mixture is ignited and burned in the combustion chamber 5. As combustion occurs, the air valve 12 and gas valve 19 are closed, stopping the supply of combustion air and fuel gas. As the exhaust gas after combustion is led out to the tail pipe 6, the combustion chamber 5 and the mixing chamber 1 become under negative pressure, and the air valve 12 and the gas valve 19 are opened. Therefore, the combustion air and fuel gas are returned to the mixing chamber 1.
The fuel is introduced into the combustion chamber 5, where it receives residual heat from the previous combustion and burns. Hereinafter, the same operation is repeated, but the blower 13 is driven only at the time of ignition, and thereafter stops because air is naturally taken in.

By the way, the pulse combustion device configured in this manner is applicable to methane fuel or methane-based fuel (gas name: 13A, 12A) as the fuel gas, and can achieve pulse combustion with a sufficient combustion range.

However, the gas currently supplied in Japan is not only methane-based fuel, but also hydrogen-based fuel with a high hydrogen content (gas name: 6C, 6B) in a wide area, and there are more than a dozen other types of gas. In particular, hydrogen-based fuel has a faster combustion speed than methane-based fuel, so the ignition position becomes unstable during pulse combustion, resulting in an extremely narrow combustion range. As a result, there are disadvantages in that the oscillation frequency tends to fluctuate, the silencing effect decreases, and the CO concentration in the exhaust gas increases.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to always be able to obtain the optimal ignition position and expansion of the combustion range even when the type of combustion gas is different, and to improve the oscillation frequency. The present invention aims to provide a pulse combustion device that can stabilize combustion and improve combustion efficiency.

[Summary of the invention]

The present invention provides a flame holder having one end fixed to the central part of the side wall of the mixing chamber, the other end extending along the axis of the mixing chamber and having a rod-shaped part protruding into the combustion chamber, and making contact with the flame band. This allows the ignition position to be set and the combustion range to be expanded.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described based on FIGS. 3 and 4. Note that the same parts as in the conventional structure of FIGS. 1 and 2 will be described using the same numbers. That is, the difference from the conventional structure is that a flame holder 30, which will be described later, is newly provided. The flame holder 30 is made of a ceramic material or a metal material, and is composed of a rod-shaped portion having a small diameter over its entire length. One end of the mixing chamber 1
The other end extends along the axis from the center of the mixing chamber 1 and connects to the combustion chamber 5.
Extends inward to a slightly protruding position. The other end of the flame holder 30 is preferably aligned with the position where the mixture reaches the ignition state, but since this position has not been clearly defined in the past, it is recommended that the other end of the flame holder 30 be provided with a certain length along the direction of flow of the air-fuel mixture. do.

In pulse combustion, the position at which the ignition occurs is determined by the mixing state of the fuel gas and combustion air and the combustion temperature. That is, ignition occurs at a location a certain distance downstream from the gas port 3 and the air port 2, where the mixing state of the fuel gas and combustion air improves and the temperature reaches a certain level or higher. When hydrogen-based fuel is used as opposed to methane-based fuel, the ignition position becomes unstable. However, if a high temperature point is provided in the mixing chamber 1 or the combustion chamber 5, the ignition position will be stabilized. The flame holder 30
is placed along the direction of air-fuel mixture flow, so it is always in contact with the flame zone and maintains it. In other words, the flame holder 30 stabilizes the ignition position and pulse oscillation frequency and expands the combustion range. In addition, the flame holder 30 becomes red-hot as it burns, and the CO concentration is reduced due to a synergistic effect with the red-hot effect. FIG. 7 shows the experimental results. In the figure, curve A represents the characteristics of the above embodiment, and curve B represents the characteristics of the conventional structure. As is clear from the figure, the combustion amount Q when the CO concentration is 30 PPM or less is about 5,300 Kcal/h or more in the above embodiment, whereas in the conventional structure, it is about 5,700 to 6,200 Kcal/h. Limited to a range. From this, it can be seen that the above embodiment has an expanded combustion range, and for example, at a combustion amount of 5000 Kcal/h, the CO concentration is reduced to about 1/3 in the above embodiment.

In addition, in the above embodiment, the flame retaining band 30 consisting of a rod-shaped portion with a small diameter was used over the entire length.
The present invention is not limited to this, but may be as shown in FIGS. 5 and 6, for example. That is, in FIG. 5, a bottomed cylindrical flame holder 30 is inserted into a through hole 31 provided in the center of the side wall of the mixing chamber 1.
Connect a. Although the diameter of the flame holder 30a is larger than that of the above embodiment, it forms a rod-shaped portion over its entire length, and this overall length is the same as that of the above embodiment. Therefore, the flame holder 30a extends along the axis from the center of the side wall of the mixing chamber 1, and its end slightly protrudes into the combustion chamber 5.
And a plurality of flame holes 32 on the peripheral wall near this end...
... will be established. A gas suction pipe 15 is provided in the through hole 31.
a gas supply box 1 having a gas hole 16, a valve seat 17, a valve holder 18, and a gas valve 19.
Connects to 4. Note that the mixing chamber 1 is provided with an air port (not shown).

FIG. 6 extends along the axis of the mixing chamber 1,
and a rod-shaped portion 3 whose end slightly protrudes into the combustion chamber 5
00a and a short rod portion 300b that is integrally provided in a direction perpendicular to this end, and the overall length is approximately T.
It is equipped with a rod-shaped flame holder 30b.
The overall length is also the same as in the above embodiment, and the mounting position is also the same as in the above embodiment, so that the ends of the short rod portion 300b and the rod portion 300a are located in the combustion chamber 5.

As described above, this embodiment has exactly the same effects as those of the above-mentioned embodiment. (The same parts as in the above embodiment are given the same numbers and the explanation is omitted.) [Effects of the Invention] As explained above, the present invention always maintains a stable oscillation frequency even when the type of fuel gas is different. This has the effect of improving fuel efficiency and combustion efficiency.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a pulse combustion device showing a conventional example of the present invention, FIG. 2 is a vertical cross-sectional view taken along the line shown in FIG. 1, and FIG. 3 is a pulse combustion device showing an embodiment of the present invention. 4 is a vertical sectional view taken along the line of FIG. 3, FIGS. 5 and 6 are longitudinal sectional views of the essential parts of the pulse combustion device showing other embodiments, and FIG. 7 is a vertical sectional view taken along the line of FIG. FIG. 3 is a characteristic diagram showing a comparison between an example and a conventional example. 1... Mixing chamber, 5... Combustion chamber, 30... Flame holder.

Claims (1)

[Claims] 1 Combustion air and fuel gas are mixed in a mixing chamber and the mixture is pulse-combusted in a combustion chamber connected to the mixing chamber, one end of which is fixed to the center of the side wall of the mixing chamber. A pulse having a flame holder having a rod-like portion whose end portion extends along the axis of the mixing chamber and projects into the combustion chamber, and is in contact with the flame zone of the air-fuel mixture. Combustion device.