JPH0549885B2 - - 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 a pulse combustion device 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 for explosive combustion.

The configuration of a conventional pulse combustion device is shown in FIG. In this pulse combustion device, the combustion air supply path 3 and the fuel supply path 4 are each equipped with check valve mechanisms 2 and 12, so that when the pressure in the combustion chamber 1 becomes lower than that on the supply side, Pulse combustion was caused by supplying combustion air and fluid fuel to the combustion chamber. The combustion state in this combustion device will be explained below. When supplying fuel to this device,
By connecting a city gas pipe to the fuel supply passage 4, etc., the supply pressure to the fuel supply passage 4 was kept constant, and fuel was supplied to the combustion chamber 1. That is, the timing of intermittent fuel supply was completely dependent on the pressure change in the combustion chamber 1. Therefore, in this configuration, there is still room for improvement in terms of increasing the pressure fluctuation width of the combustion chamber 1 and the combustion load fluctuation width.

More specifically, in the case of this structure, as shown in FIG. 5, when the fuel supply pressure A is constant and the combustion chamber pressure B changes from positive pressure to negative pressure, the combustion supply amount to the combustion chamber 1 changes. C is the time from the time _t1 when the combustion chamber pressure B becomes lower than the fuel supply pressure A to the time when it becomes higher.
During t ₂ the fuel supply is averaged, and combustion takes place on average in the combustion period from time t ₃ to t ₄ . the result,
Maximum positive pressure value p ₁ and maximum negative pressure value p ₂ of combustion chamber pressure B
is small compared to the amount of fuel supplied, and it is not possible to sufficiently efficiently heat the fluid with the long and thin tail pipe 6 using the high pressure of the combustion exhaust gas, and the amount of intake air for combustion is insufficient. There were drawbacks such as not being able to carry out load combustion, and furthermore, not being able to carry out low load combustion due to the low fuel concentration.

Therefore, an object of the present invention is to sufficiently increase the range of pressure fluctuations in the combustion chamber and the range of combustion load fluctuations by improving a pulse combustion device.

Therefore, the characteristic configuration of the pulse combustion device according to the present invention is that the check valve mechanism for preventing backflow disposed in the fuel supply path is a check valve on the discharge side, and when the combustion chamber is in a positive pressure state, fluid is supplied to the combustion chamber side. It is provided with a diaphragm pump for supplying fuel, and directly and separately supplies fluid fuel and combustion air to the combustion chamber from a fuel supply passage and a combustion air supply passage.

And its effects are as follows.

By employing this configuration, the fluid fuel is supplied to the combustion chamber at a predetermined time under the action of the diaphragm pump at a higher pressure and in a more concentrated state than before. This supply timing depends on the positive pressure state of the combustion chamber. On the other hand, combustion air is supplied to the combustion chamber when the combustion chamber is in a negative pressure state, as before. That is, in this configuration,
It becomes possible to make the supply timings of air and fluid fuel different. Furthermore, the fuel and combustion air must enter the combustion chamber separately before they are mixed. Here, in order to sufficiently widen the range of pressure fluctuations and combustion load fluctuations in the combustion chamber, it is preferable that the fuel be led to a combustion state with as much concentration of fuel as possible. This is accomplished by a feeding mechanism. An example of a combustion situation of pulse combustion in this pulse combustion apparatus will be explained in more detail based on FIG.

When adopting this configuration, as shown in the figure,
The combustion energy generated at or around the time point _t5 when the combustion chamber pressure B becomes zero during the combustion time _t3 to _t4 is the most efficient at the maximum negative pressure value _p1 of the combustion chamber pressure B.
is used to increase and subtract the maximum negative pressure value p ₂
It can also be made to act to increase the That is, the point in time when the combustion chamber pressure B changes from negative pressure to positive pressure.
From _t5 , before the set time τ, that is, the time commensurate with the ignition delay time, fuel supply is performed intensively, and the supply pressure in the fuel supply path is changed, so that the state of change in the fuel supply amount C is appropriate. As a result, the fluctuation range of the combustion chamber pressure B can be increased relative to the total amount of fuel supplied.

As a result, by effectively utilizing the extremely high combustion exhaust gas pressure, the elongated tailpipe can efficiently heat the fluid.Also, even when the amount of fuel supplied increases, the large negative pressure provides sufficient pressure in the combustion chamber. In addition, even if the amount of fuel supply decreases, the concentration of fuel can be sufficiently high through concentrated supply, and stable combustion can be achieved, and the fluctuation range of combustion load can be sufficiently widened. It became like that.

Next, an example will be described.

As shown in FIG. 1, a mixing head 5 is provided at one end of the combustion chamber 1 to mix air from the combustion air supply path 3 with a backflow prevention valve mechanism 2 and gas from the fuel gas supply path 4. At the same time, a tail pipe 6 forming an exhaust path for combustion exhaust gas is connected to the other end of the combustion chamber 1, and a starting spark plug 7 is attached to the combustion chamber 1, and moves back and forth as the pressure in the combustion chamber 1 changes. Diaphragm 8, fuel gas is supplied from the supply path 9 to the gas chamber 1
A diaphragm pump P having a backflow prevention valve mechanism 11 that allows fuel gas to flow only into the gas chamber 10 and a backflow prevention valve mechanism 12 that allows fuel gas to flow only into the supply path 4 from the gas chamber 10 is provided. A tank 13 and a valve 14 are provided to adjust the natural frequency due to pressure changes, and a honeycomb-shaped flameproofing device 15 is provided to prevent flames from flowing into the diaphragm 8 side.

The operation of the above-mentioned pulse combustion device will be explained.
At startup, an electric fan (not shown) that supplies fuel air under pressure is operated to supply fuel gas and combustion air to the combustion chamber 1 at an appropriate mixing ratio, and the spark plug 7 is used to supply the inside of the combustion chamber 1. causes an explosion. As a result, due to the dynamic inertia of the combustion exhaust gas accompanying the explosion,
Combustion air is fed into the combustion chamber 1 in appropriate amounts from the supply path 3, and the diaphragm 8 accompanying the explosion
As a result of this movement, a suitable amount of fuel gas is sent into the combustion chamber 1 from the gas chamber 10, and the flame remaining in the combustion chamber 1 ignites again, causing another explosion, and this operation is repeated. Note that the operation of the electric fan and the spark plug 7 is stopped when pulse combustion becomes stable.

Then, due to the intermittent pressurized supply of fuel gas by the diaphragm pump P, the supply pressure in the supply path ₄ changes, and as shown in FIG. Fuel gas is supplied to the combustion chamber 1 between ₆ and combustion end time _t4 , and the combustion chamber pressure B changes from negative pressure to positive pressure at time _t7 , which is a set time τ before time _t5. At this point, the fuel supply amount C reaches its maximum, and fuel is supplied intensively.
Or it will be close to that. Note that the set time τ is obtained by setting the capacity of the tank 13 and the opening degree of the valve 14 in accordance with the combustion frequency and the like. That is, the timing of supply to the combustion chamber 1 is as follows:
With respect to the discharge timing of the diaphragm pump P, there is a phase delay in relation to the flow path length from the pump P to the combustion chamber 1 and the volume of the tank 13 attached thereto. Therefore, by lengthening the supply path or increasing the volume of the tank 13 (and by adjusting the resonance frequency with the valve 14),
The timing of supplying the fuel gas to the combustion chamber 1 can have an adjusted phase delay with respect to the discharge timing of the diaphragm pump P.

Next, another embodiment of the present application will be described.

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.

When liquid fuel is supplied by the diaphragm pump P shown in FIG. 1, as shown in FIG.
A balloon 16 is placed inside the tank 13 connected to the fuel supply path 4.
, and use the deformation of the balloon 16 to appropriately set the fuel supply pressure change.

The pulse combustion device can be used for various heating purposes, such as heating the fluid by positioning the tail pipe 6 etc. in the fluid, or for the purpose of utilizing exhaust energy, and the specific configuration can be changed as appropriate. be.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing an embodiment of a pulse combustion device used in the present invention, and FIG. 2 is a graph showing the operating state of the device. FIG. 3 is a sectional view of essential parts showing another embodiment of the apparatus used in the present invention. FIG. 4 is a sectional view showing an example of a conventional device, and FIG. 5 is a graph showing the operating state of the conventional device. DESCRIPTION OF SYMBOLS 1... Combustion chamber, 2, 12... Valve mechanism for backflow prevention, 3... Combustion air supply path, 4... Fuel supply path, 6... Tail pipe.

Claims (1)

[Claims] 1. On one end side of the combustion chamber 1, a backflow prevention valve mechanism 2,
12, the fuel supply path 4 and the combustion air supply path 3 are connected to the other end, and a tail pipe 6 forming a combustion exhaust gas discharge path is connected to the fuel supply path 4 and the combustion air supply path 3 through A pulse combustion device configured to cause fluid fuel and combustion air to flow into the combustion chamber 1 for explosive combustion, wherein the backflow prevention valve mechanism 12 disposed in the fuel supply path 4 is a discharge side check. a valve, and the combustion chamber 1
a diaphragm pump P that supplies the fluid fuel to the combustion chamber 1 side under a positive pressure state, the fuel supply passage 4 and the combustion air supply passage 3
A pulse combustion device that more directly and separately supplies the fluid fuel and the combustion air to the combustion chamber 1.