JPS6049805B2 - liquid fuel combustion equipment - Google Patents

Description

[Detailed description of the invention] The present invention relates to liquid fuel combustors.

Conventionally, there have been gun types, pot types, wick types, etc. as combustors that use liquid fuel such as petroleum, but in all cases, the amount of combustion can be adjusted by changing the amount of fuel supplied to the combustion part. It has been outdated and has the following drawbacks. 1. Combustion should preferably be carried out at a constant air-fuel ratio expressed by a stoichiometric ratio.
Conventionally, adjusting the combustion amount greatly changes the air-fuel ratio, worsening the quality of combustion, increasing the amount of toxic carbon monoxide in the exhaust gas, and emitting large amounts of tin. They clog the combustor's exhaust gas passage, pollute the surrounding area, reduce thermal efficiency, and in extreme cases can make it impossible to continue combustion, resulting in a misfire.

2. In order to minimize the above drawbacks,
Practical inconveniences arise because the range in which the combustion amount can be adjusted is limited to an extremely narrow range or to discontinuous combustion amounts.

3. Since the adjustment device for changing the fuel supply amount has to come into contact with the fuel, it may be corroded by water, dirt, organic acids, etc. mixed in the fuel, malfunction due to adhesion of tar, etc.
Fuel leakage from the operating section was likely to occur, and inspection and maintenance were difficult.

The present invention provides a liquid fuel combustor that does not cause the above-mentioned drawbacks when adjusting the amount of combustion, and one embodiment thereof will be described in detail below.

FIG. 1 is a cross-sectional view of a combustor having a linear combustion section, taken approximately at the center in the longitudinal direction of the combustion section perpendicular to the longitudinal direction.

1 is a burner head made of a heat-resistant porous material, 2 is a wicking material made of a porous material that has good liquid fuel absorption properties, 3 is a liquid fuel, and 4 is a liquid fuel supply pipe.

In addition, the wicking material 2 comes into contact with the fuel 3 at the lower part, and the wicking material 2
The fuel 3 is sucked up into the burner head 1 and introduced into the vaporization section in the upper part of the burner head 1. 5 is an electric heater, which is mainly made of a metal or non-metallic material that generates heat when energized, preferably has a film-like or layered shape that allows gas to pass through, and has an electric wire and an insulated wire formed in a fiber-like shape. A metal foam, a self-regulating heater with a large number of holes, etc. are used.

6 is a mixing chamber consisting of a space into which the vaporization part of the burner head 1 looks, 7 is a combustion chamber, and 8 is a flame port located on the downstream side of the mixing chamber 6, which is made of a heat-resistant material such as metal or ceramic. The combustion chamber 7 has an opening 12 such as a hole or slit through which the air-fuel mixture passes, and has a shape suitable for combusting the air-fuel mixture.

9 is an air supply pipe and has an air flow rate adjustment device 10;
Primary air is supplied to the mixing chamber 6, and secondary air is supplied to the combustion chamber 7.
Supply as indicated by the arrow in the figure.

There may also be a device that adjusts the flow rates of primary air and secondary air independently.

11 is on fire.

The relationship between the amount of primary air and the amount of combustion in this combustion device is as shown in Figure 3.It has the characteristics that the amount of combustion can be automatically adjusted by adjusting the flow rate of the primary air, and the Since the combustion amount is approximately proportional to the primary air flow rate, it has the characteristic that it can be adjusted steplessly. This is the vapor pressure in the liquid phase of the fuel in the vaporization section. This is obtained by controlling the vapor pressure difference between the liquid phase and the vapor pressure of the contacting gas phase by controlling the primary air flow rate.

At this time, the electric heater 5 heats the liquid phase fuel in the vaporization section to a temperature at which it is easily vaporized, and prevents the temperature of the liquid phase fuel in the vaporization section from decreasing due to the heat of vaporization of the fuel, and appropriately Its function is to maintain the temperature at a certain level. The appropriate temperature level in this case does not necessarily refer to an extremely narrow temperature range; for example, a method of supplying a constant amount of electricity regardless of the amount of combustion may be expected to produce a satisfactory effect, but this method It is preferable to adopt this method only when the variable range of the combustion amount is relatively narrow or when the proportionality between the primary air amount and the combustion amount is not required to be very strict. On the other hand, if the variable range of the combustion amount is set as wide as possible and emphasis is placed on the proportionality between the amount of primary air and the amount of combustion, the amount of current applied should be controlled so that the liquid phase fuel in the vaporization section is maintained at a nearly constant temperature. When using kerosene, the temperature is preferably maintained at about 180 to 19°C, and in any case it is preferably maintained at 120 to 350°C. Next, when looking at the relationship between the total air amount and the combustion amount when adjusting the sum of the flow rates of primary air and secondary air, the ratio between the two is almost constant regardless of changes in the combustion amount, as shown in Figure 4. It has the characteristic of being able to maintain the stoichiometric ratio of
Furthermore, the combustion efficiency for combustion at a constant air-fuel ratio is extremely high, and as shown in FIG. 5, carbon monoxide in the exhaust gas is extremely low, and the generation of tin is also characteristically negligible.

Note that tar builds up in the vaporization section of the burner head 1 and causes clogging of the pores, which may impair the fuel supply to the vaporization section. In this case, the fuel supply is completely stopped and the electric heater 5 It is effective to energize the tank to raise the temperature of the vaporizer and burn the tar.

Therefore, it is desirable to have an operation section that can perform such operations automatically or manually.

Furthermore, in order to prevent combustion in the mixing chamber 6, it is preferable that the electric heater 5 does not become red hot during combustion and has a temperature of 350°C or less. It is also effective to use a porous metal object such as a metal net.

As can be seen from the above embodiments, the present invention provides a burner head containing liquid fuel in a liquid phase state, and further premixes primary air into a premixing chamber in which the fuel vaporization section of the burner head extends. In addition to supplying secondary air to the flame port downstream of the chamber, the amounts of the fuel vaporization air and secondary air are varied using a flow rate controller, and the amount of the burner head is adjusted according to the amount of primary air. The liquid fuel is vaporized from the fuel vaporization section, premixed in the premixing chamber, and then combusted by supplying secondary air at the flame port, which is difficult to achieve in the past. Since the combustion amount can be easily varied according to the amount of air for vaporizing the fuel, and the air-fuel ratio at each combustion amount is substantially constant, extremely good combustion unique to premix combustion can be performed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a liquid fuel combustion device according to an embodiment of the present invention, and FIG. 2 is a perspective view of a flame port in the same device.
FIGS. 3, 4, and 5 are characteristic diagrams of the device. 1... burner head, 2... wicking material,
4... Liquid fuel supply pipe, 5... Electric heater, 6... Mixing chamber, 7... Combustion chamber, 8... Flame Mouth part, 9... air supply pipe,
10...Air flow rate adjustment device.

Claims (1)

[Claims] 1. A burner head containing fuel in a liquid phase, a fuel supply section that supplies fuel to the burner head, an electric heating element that heats the vaporization section of the burner head, and a non-combustion mixture that the vaporization section of the burner head desires. and a flame port provided downstream of the mixing chamber, and supplies primary air to the mixing chamber and supplies secondary air to a combustion chamber provided downstream of the flame port. Each passage is provided, and the air passing through the primary and secondary air passages is configured to be variable with a flow rate adjustment device.
This flow rate adjustment device is a liquid fuel combustion device configured to simultaneously adjust the amount of fuel vaporized from the vaporization section of the burner head by adjusting the flow rate of the air.