JPH03271609A - Combustion device for liquid fuel - Google Patents

Abstract

PURPOSE:To make compact the title device, by a method wherein both foaming air fed to a porous element for a foam-producing device and burning air fed to a burning device are fed by a common fan. CONSTITUTION:A foam combustion device is composed of a burning device 1 and a foam-producing device 2, and a porous element 7 is provided in the foam-producing device 2. The burning device 1 is composed of an inlet port 10 for burning-air and a flame-holding device 9. Both a burning air feed pipe 12, and an air feed pipe 13 for feeding air to the foam-producing device 2, are connected to a fan 14 for common use, and a damper 11 is also provided. In such a way, since a fan for burning-air is used also for air for foaming, the number of parts is reduced and the title device can be made compact. Since the air feed pipe 13 for producing foam is connected to a part adjacent to the outlet port of the fan 14, a high pressure is kept constant, and on the other hand, the amount of the burning air can be controlled by the afterflow control of a damper 11.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to the combustion of liquid fuels in a wide range of applications from domestic kerosene stoves to industrial kilns.

(Prior Art) Combustion of liquid fuel includes combustion for the purpose of heating as in a stove, combustion for heating a heated object, and combustion as a power generating engine such as an internal combustion engine.

Conventional combustion methods include either directly vaporizing liquid fuel and combusting it, or splitting it into fine mist using a spray device and then combusting it.

The present applicant has previously provided in Japanese Patent Application Laid-Open No. 1-95205 a method for foaming liquid fuel and continuously burning it in a combustor, and the effect is particularly remarkable when applied to a kerosene stove.

FIG. 2 is an explanatory diagram of a conventional example, in which a porous element 7 is provided in a foam generator 2, and gas is supplied from a pump 4 to foam the fuel. Combustion air is supplied to the combustor 1 from a separate system, and the foamed fuel is combusted.

In this way, by turning the fuel into foam and burning it, the amount of air blown from the gas supply pipe can be adjusted; and 2.
By changing the amount of air supplied from the secondary air pipe, combustion characteristics such as combustion amount and flame shape can be freely controlled.

(Problems to be Solved by the Invention) In the case of liquid fuel combustion devices, there is a strong demand for making it possible to adjust the thermal power over a wide range and to make the device more compact with fewer parts.

The present invention provides a liquid fuel combustion device that meets the need for compactness.

(Means for Solving the Problems) The present invention provides a foaming combustion device for liquid fuel in which a combustor and a foam generator are connected, in which foaming air is supplied to a porous element of the foam generator and air is supplied to the combustor. This is a liquid fuel combustion device characterized by supplying combustion air using a common blower fan, and the foaming air supplied to the porous element is taken out immediately after the blower fan discharges, so that a constant pressure and flow rate is maintained. This includes ensuring that combustion air is taken out as a wake stream through a damper and controlling the air volume.

In foaming combustion of liquid fuel, secondary air for combustion must be supplied to the combustor.

This is because the foaming ratio (foam volume/liquid fuel volume) obtained only with liquid fuels such as kerosene and diesel oil is usually around 5 to 50 times, and the required ratio of air required for complete combustion is approximately 9000 times. This is because the amount of air in the foam is nowhere near that amount.

However, for combustion, some of the air supplied from the gas supply pipe does not remain in the foam and can be used directly as combustion air, so the amount of air supplied from the secondary air pipe 7 is equal to the theoretical combustion air. 250% of the amount is a preferred range.

In the present invention, since the above-mentioned combustion air is also used as a blower fan for foaming air, the number of parts can be reduced and the device can be made compact.

The present invention will be explained below based on the drawings.

The foaming combustion device in the present invention includes a combustor 1 and a foam generator 2.
A porous element 7 is installed inside the foam generator 2. The combustor 1 has a combustion air inlet lO, and a flame stabilizer 9
will be established. Further, the combustion air supply pipe 12 and the air supply pipe 13 that supplies the foam generator 2 are connected to a common fan 14, with a damper 11 interposed therebetween.

According to experiments conducted by the present inventors, in the conventional example, when the opening of the metal filter is 40, for example, the amount of supplied air is 0.3 m'/H, the bubble diameter is uniform, and combustion occurs as bubbles, but this pressure drop was 150 mmH2O.

On the other hand, the amount of combustion air supplied at this time is 75rr? /H, the pressure loss was only 35 mm H20.

Furthermore, when the amount of air supplied for foam generation is maintained at a substantially constant value throughout the combustion period, foam generation is stable.

Therefore, in the present invention, the supply pipe 13 for foam generation is replaced by the fan 14.
was connected immediately after the discharge of damper H to ensure a constant high pressure, and on the other hand, succeeded in extracting the amount of combustion air as a wake of damper H by Rtjk control. For this reason, it is preferable that the damper 11 and the supply valve 15 of the fuel supply port 8 be automatically controlled.

The porous element 7 of the bubble generator 2 is made of sintered metal or ceramics, but an element with as low a pressure drop as possible must be selected. The physical properties of the element that affect pressure drop include porosity and sintered body density, and experiments show that the porosity is 35 to 45% and the sintered body density is 4.0 to 8.0.
Good results were obtained with sintered metal of g/-. Here, the air volume control according to the present invention can also be applied to rotation speed control using an inverter, air volume control using a fluid coupling, and the like.

Furthermore, by adding a polymer or a surfactant to the liquid fuel, it is possible to increase the foaming ratio and reduce the load on the blower fan.

In other words, polymers, surfactants,
Stable foam production is possible by mixing a silicone resin or a mixture thereof, or a gas oil with good foaming properties to increase the surface viscosity and lower the surface tension, thereby improving the foaming properties.

In the present invention, the high pressure immediately after discharge from the fan 14 is supplied to the foam generation supply pipe 3, and a damper 11 is provided downstream from the connection point of the foam generation supply pipe 13, so that the amount of secondary air for combustion is controlled by the air volume. However, since the opening and closing of the damper is controlled proportionally to the amount of fuel supplied by the fuel supply valve 15, the fan is operated at a constant rotation speed.

(Effects of the Invention) Since the present invention supplies foaming air and combustion air using a common blower fan, the number of parts of the device is significantly reduced.

In addition, since the air volume is controlled by interposing a damper, there is an effect that the combustion thermal power can be adjusted over a wide range.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the present invention, and FIG. 2 is an explanatory diagram of a conventional example. Agent Patent Attorney Tatsuo Chanoki Figure 1 Figure 2

Claims (1)

[Claims] 1. In a liquid fuel foaming combustion device in which a combustor and a foam generator are connected, foaming air supplied to the porous element of the foam generator and combustion air supplied to the combustor. A liquid fuel combustion device characterized in that the fuel is supplied by a common blower fan. 2. According to claim 1, the air for foaming to be supplied to the porous element is taken out immediately after the discharge of the blower fan to ensure a constant pressure and flow rate, and the air volume is controlled as the air for combustion is taken out as a wake through a damper. Combustion device as described.