JPH0348407B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a fuel supply passage and a combustion air supply passage at one end of the combustion chamber via a backflow prevention valve mechanism, and a combustion exhaust gas exhaust passage at the other end. The present invention relates to an improvement in a fuel supply section of a pulse combustion apparatus configured to connect a tail pipe forming a combustion chamber to cause fluid fuel and combustion air to flow into the combustion chamber by the dynamic inertia of combustion exhaust gas accompanying an explosion to cause explosive combustion.

Conventionally, as shown in FIG. 3, fuel from a supply passage 11 was distributed and supplied to all of the plurality of air passages 5 defined by a mixing head 14 through a discharge port 11a.

However, in pulse combustion, combustion air is drawn into the combustion chamber 1 due to pressure fluctuations within the combustion chamber 1, and even if the amount of fuel supplied decreases, the range of fluctuations in the internal pressure of the combustion chamber 1 does not become much smaller. Therefore, when the amount of fuel supplied decreases, there will be excess air in the combustion chamber 1, resulting in incomplete combustion or unstable combustion. Therefore, the turndown ratio will decrease, for example, from 1/1.5 to 1/1/2.
There was a drawback that the size was about 3.

An object of the present invention is to improve the fuel supply configuration so that stable combustion can be reliably maintained even when the amount of fuel supplied is reduced, and the turndown ratio can be increased.

The characteristic configuration of the fuel supply section according to the present invention is that in a pulse combustion device, a large opening in the combustion chamber allows
Further, the flame arresting chambers connected to the downstream air passages of the valve mechanism for preventing backflow for combustion air through small openings are separated from the main air passage, and the discharge port of the fuel supply passage is connected to the flame retention chamber. The functions and effects of the new facility are as follows.

In other words, when supplying fuel to the combustion chamber, if the area of the small opening that supplies air to the flame holder chamber is set so that some of the fuel remains in the flame holder chamber in a slightly air-deficient state, then Even in the event of an explosion, the remaining fuel and air in the flaming chamber gradually cause combustion, and even when the combustion chamber is exhausted, the remaining fuel and air continue combustion in the flaming chamber. When air is drawn into the combustion chamber, combustion in the flame holder chamber can be continued by the air and fuel supplied to the flame holder chamber.

As for the continuation of combustion in the flame holding chamber as described above, even if the amount of fuel supplied to the combustion chamber is considerably reduced, the amount of air flowing into the flame holding chamber remains almost constant.
This is because the amount of fuel supplied is extremely large compared to the volume of the flame chamber, so this process continues without any change.

Therefore, even if the amount of fuel supplied decreases to such an extent that the air-fuel ratio in the combustion chamber becomes unsuitable for stable combustion, the flame in the flame retention chamber will effectively act as an ignition source into the combustion chamber through the large opening, resulting in stable combustion. combustion takes place in the combustion chamber.

As a result, it is now possible to reliably maintain good pulse combustion even if the amount of fuel supply is reduced by a large amount, and the turndown ratio can be increased to about 1/5 compared to conventional methods. It is now possible to provide a pulse combustion device that can be increased in width and is convenient for heating, etc. with large load fluctuations.

Next, examples will be shown.

As shown in FIG. 1, a combustion air supply path 3 equipped with an electric fan 2 is connected to one end of the combustion chamber 1 via a backflow prevention valve mechanism 4a.
A partition wall 7 is provided on the downstream side of the main air passage 5 and the flame retention chamber 6 extending all around the main air passage 5, and a small opening 8 is provided to connect the downstream air passage 3a of the valve mechanism 4a and the flame retention chamber 6. , and a large opening 9 connecting the flame holder chamber 6 and the combustion chamber 1 is formed, and the discharge port 11a of the fuel gas supply path 11 having the backflow prevention valve mechanism 4b and the flow rate control valve 10 is connected to the flame holder chamber 6. A straight tail pipe 12 that forms a combustion exhaust gas discharge path is connected to the other end of the combustion chamber 1, and a starting spark plug 13 is attached to the combustion chamber 1, and a pulse combustion device is installed. It is configured.

The operation of the above-mentioned pulse combustion device will be explained.
At startup, the electric fan 2 is operated to supply fuel gas and combustion air to the combustion chamber 1 at an appropriate mixing ratio,
Moreover, an explosion is caused within the combustion chamber 1 by the spark plug 13. As a result, due to the dynamic inertia of the combustion exhaust gas accompanying the explosion, an appropriate amount of combustion air is fed into the combustion chamber 1 from both supply paths 3 and 11, and the flame remaining in the combustion chamber 1 re-ignites the combustion air, causing it to ignite again. An explosion occurs and the action repeats. Note that the operation of the electric fan 2 and the spark plug 13 is stopped when pulse combustion becomes stable.

Further, an appropriate amount of air is supplied through a small opening 8 into the flame holder chamber 6 so that there is a slight air shortage there and combustion is always continued. It is stably repeated using the flame inside 6 as the ignition source.

Incidentally, the areas of the small opening 8 and the large opening 9 are appropriately set in accordance with the characteristics of the pulse combustion device.

Next, another embodiment will be described.

To form the flame trapping chamber 6, as shown in FIG. 2, the flame trapping chamber 6 is arranged in the center of an appropriate number of groups of main air passages 5 arranged in an annular shape, and other specific configuration changes are made as appropriate. is possible.

As the fuel, gas fuels such as city gas, natural gas, propane gas, etc. are mainly used, but liquid fuels such as oil can also be used, and in short, any fluid fuel may be used.

The pulse combustion device can be used for various heating purposes, such as heating the fluid by positioning the tail pipe 12 in the fluid, or for the purpose of utilizing exhaust energy, and the specific configuration can be changed as appropriate. be.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention;
FIG. 2 is a schematic cross-sectional view showing another embodiment of the present invention. FIG. 3 is a schematic sectional view of a conventional example. 1... Combustion chamber, 3... Combustion air supply path, 3a
... Air path, 4a, 4b ... Valve mechanism for preventing backflow,
5... Main air path, 6... Flame holding chamber, 8, 9... Opening, 11... Fuel supply path, 11a... Discharge port, 1
2... Tail pipe.

Claims (1)

[Claims] 1 A backflow prevention valve mechanism 4 is installed at one end of the combustion chamber 1.
a, 4b, the fuel supply path 11 and the combustion air supply path 3 are connected to the other end, and a tail pipe 12 forming a combustion exhaust gas exhaust path is connected to prevent the movement of combustion exhaust gas due to an explosion. In a pulse combustion device configured to cause fluid fuel and combustion air to flow into the combustion chamber 1 by inertia for explosive combustion, the combustion chamber 1 is provided with a large opening 9 and a valve mechanism for preventing backflow to the combustion air. Flame holding chambers 6 connected to the downstream air passages 3a of 4a through small openings 8 are separated from the main air passage 5, and a discharge port 11a of the fuel supply passage 11 is provided in the flame holding chamber 6. Fuel supply section of a pulse combustion device.