JPH0428967B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an improvement of a pulse combustor used as a heating device for industrial, commercial or domestic water heaters, hot air fans, etc.

Structure of the Conventional Example and Its Problems A conventional pulse combustor is composed of a combustion chamber, a tail pipe, an air passage having an air valve, and a fuel passage having a fuel valve. Combustion air is supplied in advance to the combustion chamber by a blower through an air passage. Further, fuel is supplied to the combustion chamber from the fuel passage. Fuel and air are mixed to form a mixture. When this air-fuel mixture is ignited, it explodes and burns, increasing the pressure in the combustion chamber, closing the air valve and fuel valve, and stopping the supply of fuel and air. The combustion gases are discharged from the tailpipe, then the pressure in the combustion chamber becomes negative pressure, the fuel and air valves are opened, the air and fuel are supplied to the combustion chamber, and at the same time, the hot combustion gases flow back and the fuel and The mixture with air is ignited and explosive combustion occurs again. Then, without air blowing from the blower, the same ignition, explosion, and suction of fuel and air occur, and regular explosive combustion continues.

In this case, the air valve was located near the combustion chamber. The reason for this is that the air valve opens and closes due to pressure fluctuations within the combustion chamber, so it is necessary to receive sufficient pressure. However, at this time, the air valve received heat from the combustion chamber and its durability was damaged, so we removed the air valve from the combustion chamber or bent the connecting part between the air valve and the combustion chamber. It was changing direction. However, the pressure from the combustion chamber was not sufficiently transmitted, causing combustion instability.

OBJECTS OF THE INVENTION The present invention overcomes the conventional drawbacks as described above and provides a pulse combustor which has an air valve with good durability and which allows the air valve to be installed in any direction.

Structure of the Invention An open tail pipe is provided in one side of the combustion chamber, a fuel passage and an air passage are provided in the other side of the combustion chamber, a fuel valve that can be opened and closed is provided in the fuel passage, and an air valve is provided upstream of the air passage. A valve chamber is installed, an air chamber is provided between the air valve chamber and the air passage, a connecting pipe is installed between the air chamber and the air valve chamber, and an air valve that can be opened and closed is provided in the air valve chamber. It is set up.

DESCRIPTION OF THE EMBODIMENTS In FIG. 1, fuel gas 13 passes through a fuel valve 11 provided in a fuel passage 10 and is supplied to the combustion chamber 1 from a nozzle 9. In FIG. On the other hand, combustion air 12 is supplied to the combustion chamber 1 through the air valve 8, the air valve chamber 7, the connecting pipe 6, the air chamber 5, and the air passage 4 by the power of a blower (not shown). Combustion air and fuel gas are mixed and ignited by a spark discharge from a spark plug 14, resulting in explosive combustion, forming a flame 15, and becoming a high-temperature combustion gas 16. The pressure inside the combustion chamber 1 increases due to the explosion, and the air valve 8 and combustion valve 11
is closed, and the supply of fuel gas 13 and combustion air 12 is stopped. Combustion gas 16 is passed through a thin tail pipe 2
and is discharged to the outside of the combustor. A cushion chamber, a muffler, or the like is often installed downstream of the tail pipe 2. When the combustion gas 16 passes through the tail pipe 2, the inside of the combustion chamber 1 becomes negative pressure, and the fuel valve 11 and the air valve 8
opens, fuel gas 13 and combustion air 12 are drawn into the combustion chamber, and the fuel gas and combustion air are mixed. At that time, high-temperature combustion exhaust gas flows back into the combustion chamber 1, ignites the mixture of fuel gas 13 and combustion air 12, and explodes again. Then, similar explosions are repeated one after another, resulting in a pulse combustion state. When the pulse combustion state is reached, fuel gas 13 and combustion air 12 are automatically sucked even if the blower is stopped.

In this way, pulse combustion continues stably, but
The pressure fluctuation values with and without an air chamber are calculated as the second
As shown in the figure. When the air chamber 5 was present, pressure fluctuations were measured within the air chamber 5, and when the air chamber 5 was not present, pressure fluctuations in the connecting pipe 6 near the combustion chamber 1 were measured. The measurement results are shown in FIG. 2a, with the vertical axis representing pressure fluctuations and the horizontal axis representing time when there is an air chamber. In this figure, the pressure fluctuations within the air chamber 5 have almost no disturbance and form a clean sine wave. This is because the pressure generated in the combustion chamber 1 passes through the narrow air passage 4 and is transmitted to the wide air chamber 5, in which the turbulence in pressure is absorbed. Air valve 8
operates at a constant frequency. In this case, the air passage 4 is narrowed by a connecting pipe 6 placed upstream of the air chamber 5,
Furthermore, pressure turbulence is reduced. Furthermore, an air valve chamber 7 is provided to effectively transmit the attenuated pressure transmitted from the combustion chamber 1 to the air valve 8, thereby stably operating the air valve 8.

However, if there is no air chamber 5, the pressure fluctuations generated in the combustion chamber 1 will propagate as they are, so the second
The waveform is deformed as shown in Figure b. this is
The air passage area is 15 cm ² with a combustion rate of 30,000 kcal/h.
This is the case. If the air passage is bent in such a case, reflected pressure waves will be added, which may create a complex beat and cause the frequency to fluctuate. Even when the amount of combustion is large, reflected waves of pressure are added, which may create a complex beat or fluctuate in frequency. When the pressure waveform is deformed in this way, the air valve 8 operates irregularly, making it difficult to suck in combustion air and emitting carbon monoxide. Also, when the combustion amount is small, the waveform becomes disturbed and irregular, so the air valve 8
movement becomes erratic, pulse combustion stops, and misfire occurs. If the air chamber 5 rises too much, the pressure inside the combustion chamber 1 will be absorbed and the pressure required to operate the air valve 8 will not be available, or the combustion amount will not be enough to operate the air valve 8. If it does, there will be a lack of air and carbon monoxide will be emitted. In this way, the volume of the air chamber 8 has an effect on the combustion performance or combustion range, but it does not necessarily show a clear relationship with the air chamber volume and changes gradually, but empirically it is estimated that 0.2 of the combustion chamber volume With the above, if the volume is about 0.6, it will burn within a range that does not pose a problem for practical use.

Effects of the Invention As explained above, the present invention provides an air chamber between an air passage connected to a combustion chamber and an air valve chamber installed upstream of this air passage, and connects the air chamber and the air valve chamber with a connecting pipe. Since the air valve chamber is equipped with an openable air valve, the complex pressure fluctuations occurring in the combustion chamber can be converted into a clean sine wave in the air chamber, reducing disturbances in the pressure transmitted from the combustion chamber to the air valve. The air valve can be operated stably, pulse combustion can be stabilized, and
Since the air chamber is provided separately from the air valve, the connecting pipe can be bent and extended, resulting in the effect of increasing the degree of freedom in the installation position and installation direction of the air valve.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a pulse combustor according to an embodiment of the present invention, and FIG. 2 is a diagram showing pressure fluctuations in the pulse combustors according to an embodiment of the present invention and a conventional pulse combustor. 1... Combustion chamber, 2... Tail pipe, 4... Air passage, 5... Air chamber, 6... Connecting pipe, 7... Air valve chamber, 8... Air valve.

Claims (1)

[Scope of Claims] 1. An open tail pipe is provided in one side of the combustion chamber, a fuel passage and an air passage are provided in the other side of the combustion chamber, a fuel valve that can be opened and closed is provided in the fuel passage, and the air passage is provided with a fuel valve that can be opened and closed. An air valve chamber is installed upstream, an air chamber is provided between the air valve chamber and the air passage, and a connecting pipe is installed between the air chamber and the air valve chamber, which can be opened to the air valve chamber. Pulse combustor equipped with air valves. 2. The pulse combustor according to claim 1, wherein an air valve is provided branching from the air chamber on a line that intersects with a line connecting the combustion chamber and the air chamber.