JPS6157967B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid fuel combustion device using a vaporization premixing method, which is used with a relatively small calorific value, such as in oil stoves and oil fan heaters, and which is desired to have a wide range of thermal power adjustment. The purpose is to improve performance when the return pipe for fuel recirculation is clogged with dirt or water frozen.

In order to obtain a stable and low amount of fuel for combustion, this type of combustion device is designed to select a part of the atomized atomized fuel, take it out, and return the remaining fuel to the tank chamber through a return pipe. It will be done.

At this time, if the end opening of the return pipe for reflux is open to the atmosphere or submerged in a shallow part of the liquid inside the tank, combustion air will leak from this opening, causing problems in the combustion state. In order to bring about
It must be constructed so that it can be submerged sufficiently deep into the liquid so that the fuel is immersed in the liquid so that the specific weight of the fuel is 1.

However, if you do this, if dirt accumulates inside the tank or water accumulates and freezes,
There is a drawback that if the opening of the return pipe for reflux is blocked, if it is blocked, the fuel will not be completely refluxed into the tank chamber, but will overflow into the atomization chamber and vaporization chamber and burn, causing abnormal flame growth. There remains the problem of dangerous out-of-control conditions such as ejection outside the vessel.

Therefore, the present invention solves the above problem by forming at least a portion of the return pipe for recirculation below the liquid level in the fuel tank chamber with a mesh body. An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In Figures 1 and 2, 1 is an atomization chamber, with a fan casing 2 and a motor casing 3 at the bottom.
and a pump casing 4 are arranged in series to form one atomization unit, which is attached to the upper part of the fuel tank chamber 5. In addition, liquid fuel heat sources used as home heaters and cookers that use forced vaporization premixing, such as oil stoves or oil fan heaters, are equipped with a separate tank (such as a cartridge tank) to ensure stable combustion. It is a known component to ensure a stable supply of fuel using an oil controller, an oil leveler, or by a leveler action with a separate tank (cartridge tank, etc.), and as a result, the liquid level of the fuel directly connected to the heat source device and supplied Level fluctuations are suppressed as much as possible, and fuel is always maintained at a constant level.

A separate tank like this (cart cartridge tank, etc.)
The pump casing 4 faces the liquid level of the fuel tank chamber 5, which is supplied with fuel from the fuel tank chamber 5 and maintains a constant liquid level. The fan impeller 6 and the pump impeller 7 are fixed on a motor rotating shaft 8 and driven by a motor 9. An oil feed path 10 is provided in the atomization unit that communicates the discharge side of the pump casing 4 with the atomization chamber 1, and a bypass portion 11 branched from a part of the oil feed path 10 has a bypass amount. A relief valve 12 is provided to regulate the amount of fuel supplied to the atomizer 13 within the atomization chamber 1. The pump casing 4 is provided with a communication port 14 that communicates the suction side with the fuel tank chamber.

The fuel damper 15 in the atomization chamber 1 is provided with an interlocking sleeve 17 for interlocking the air damper 16, and the opening degrees of the atomized fuel outlet 18 and the air damper 16 are both changed by the operation of the fuel damper 15. . Therefore, the atomized fuel particles and combustion air atomized by the atomizer 13 are
The fuel damper 15 allows the combustion amount to be varied over a wide range while always maintaining the optimum air-fuel ratio. A return oil passage 19 communicating between the atomization chamber 1 and the fuel tank chamber 5 is provided near the atomized fuel outlet 18, and the atomized particles from the atomizer 13 are removed by the fuel damper 15. The remaining fuel is returned to the fuel tank chamber 4. 20 is return oil path 1
This is a return pipe for reflux attached to the fuel tank chamber 5, and at least a portion of this return pipe 20, which is immersed in the liquid from the liquid level 21 in the fuel tank chamber 5, is formed by a filter net 22.

In the above configuration, the fuel in the fuel tank chamber 5 is fed under pressure to the atomizer 13 via the oil feed path 10 at a continuous constant flow rate and is atomized. A part of the atomized particles is selectively sent to the vaporization chamber 23 by the fuel damper 15, and the remaining fuel is returned from the oil passage 19 to the fuel tank chamber 5 via the return pipe 20 for recirculation and is recirculated. . In addition, fuel liquid constantly adheres to the filter screen 22, and therefore, when the bottom of the filter screen is blocked due to freezing of water mixed into the fuel tank chamber 5, in other words, the vicinity of the outlet of the end of the return pipe 20 becomes contaminated with water. If the water becomes blocked due to freezing (the specific gravity of water is heavy and it accumulates in lumps at the bottom of the fuel tank chamber and becomes ice at low temperatures), the specific gravity of water is heavier than the fuel, so it will not adhere to the gaps in the filter screen 22. It accumulates in a lump at the bottom of the fuel tank chamber 5.

Also, compared to the area of the end of the return pipe (A′=π/4 D ² ; D……inner diameter of the return pipe), the area of the gap in the net 22 (A″=n・π/4d ² ; n……… ...the number of gaps, d....gap diameter) is small, the resistance increases, and the liquid level in the return pipe 20 becomes higher by h' than the liquid level in the fuel tank chamber 5 facing the atmosphere.

That is, the head inside the return pipe 20
This increase in pressure causes the fuel that has been circulating in the return pipe 20 to be pushed out through the gaps in the filter net 22 into the fuel tank chamber 5, and is maintained at a constant pressure in a balanced state. It is maintained.

In this way, the return pipe 2 can be used even in the event of an unexpected situation such as freezing of water accumulated at the inner bottom of the fuel tank chamber 5.
The liquid level in 0 is kept constant (h' rise), and the fuel flows out into the tank chamber through the gap in the filter screen 22.

Further, when the return pipe wall is not a mesh body as in the conventional example, only the pressure Pa applied to the liquid surface (boundary surface) in the direction of the tube end exit in the liquid needs to be taken into consideration. Therefore, in order to prevent spouting and leakage, it was sufficient to set the tip of the return pipe to a depth h in the liquid so that h>Pa/roil (1).

However, when forming the filter net 22 as in the present invention, in order to prevent air from blowing out or leaking due to the pressure Pa of the fan, a pressure balance with respect to the pressure Pa at the following two interfaces must be maintained and ensured. It's a good thing.

That is, one is the pipe end outlet of the return pipe 20. Since this is only a netted portion of the fuel below the water surface, the depth h of the return pipe 20 in the liquid is ensured, and the above inequality (1) is satisfied. Therefore, air blowout and leakage can be prevented.

Next is the gap formed between each strand of the net. Here, if we consider a circular gap with a diameter d that is a distance Z below the liquid level of the fuel in contact with the atmosphere in the fuel tank chamber 5, the return pipe 2
The force Fa due to air within 0 is Fa=π/4d ²・Pa …………(2) And the force Ff due to fuel is Ff=π/4d ²・roil・Z+πd・S …………(3) S : Expressed by surface tension.

Here, at the position where the liquid level Z≒0, equation (3) is Ff′=πd・S ………(3)′ Therefore, the force is only due to surface tension.

Therefore, looking at the difference between (3)′ and (2), Δf=Ff′−Fa=πd(S−d/4Pa), and if S−d/4Pa≧0, Δf≧0 and the pressure balance is This means that air will not leak out.

The mesh used here is a filter mesh that can be used as a filter, etc., and the gap d is d≦0.1 (mm), and even if Pa=30mmH ₂ O, d/4Pa=1/4×1 × ^10-2 ×3=0.75× ^10-2 (gf/cm
), and the surface tension of the fuel S (＞3.0×10 ^-2 (gf/
cm)) smaller.

As a result of the above, air continues to be trapped within the return pipe 20.

As is clear from the above, the present invention is directed to recirculating the fuel in the atomization chamber that has not been supplied to the vaporization chamber into the fuel tank chamber through a return pipe, and in which the fuel in the atomization chamber is at least below the liquid level in the fuel tank chamber of the return pipe. Since a portion of the return pipe is formed of a mesh, even if the bottom of the fuel tank chamber of the return pipe is blocked by dirt or frozen water, the fuel will flow back into the fuel tank chamber through the mesh of the mesh, and should be refluxed. Abnormal combustion due to fuel overflowing into the atomization chamber or vaporization chamber will no longer occur.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the liquid fuel combustion apparatus of the present invention, and FIG. 2 is an enlarged sectional view of a return pipe portion of the liquid fuel combustion apparatus. 1... Atomization chamber, 5... Fuel tank chamber, 6... Fan impeller, 7... Pump impeller, 10...
Oil supply path, 13...Atomizer, 14...Communication port,
19...Return oil path, 20...Return pipe, 2
2... Filter net (mesh body), 23... Vaporization chamber.

Claims (1)

[Claims] 1. An atomization chamber that atomizes the fuel supplied from the fuel tank chamber, where fuel is supplied from a separate tank and the liquid level is kept constant, and atomized particles of fuel generated in this atomization chamber. means for selectively taking out a part of the fuel and feeding it into the vaporization chamber; means for feeding combustion air into the vaporization chamber; and means for refluxing the fuel in the atomization chamber that has not been supplied to the vaporization chamber into the fuel tank chamber. and a return pipe immersed below a certain liquid level, and at least a part of the return pipe below the liquid level in the fuel tank chamber is formed of a net.