JPH116618A - Liquid fuel combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of transient excessive oxidizing reaction and the lowering of the position of combustion upon combustion, by a method wherein catalyst is not carried in a non-carrying part. SOLUTION: In a liquid fuel combustion device provided with a catalyst carried by a combustion burner 20 to effect the oxidizing reaction of unburnt evaporated fuel, a flame detecting means 50 arranged above the combustion burner 20 and detecting combustion flame, and a control means for controlling the combustion based on the output of the flame detecting means 50, a flame port net 282, not carrying the catalyst to effect oxidizing reaction of the unburnt evaporated fuel, is provided at a position opposed to the flame detecting means 50 of the combustion burner 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid fuel combustion device such as an oil fan heater.

[0002]

2. Description of the Related Art A conventional liquid fuel combustion apparatus (specifically, an oil fan heater) will be described below with reference to the drawings.

FIG. 5 is a front view of a main part of a conventional liquid fuel combustion apparatus, FIG. 6 is a plan view of a main part of a conventional liquid fuel combustion apparatus, and FIG. 7 is a view of the combustion burner shown in FIGS. It is an exploded perspective view.

[0004] The conventional liquid fuel combustion device includes a carburetor 10 and a combustion burner 20 as shown in FIGS. 5 and 6.

[0005] The vaporizer 10 includes a combustion heat recovery unit 11,
Vaporization heater 12 for heating and vaporizing liquid fuel
And a thermistor 13 for detecting the temperature of the vaporizer 10
And a nozzle 14.

The heat recovery section 11 is for reducing the power consumption of the vaporization heater 12, and has a base end fixed or integrated with the vaporizer 10. Further, the front end faces above the combustion burner 20, and the combustion burner 20
Are arranged so as to be exposed to the combustion flame formed therein.

[0007] As shown in FIG. 7, the combustion burner 20 uses a metal net in the flame hole. The combustion burner 20
Is the burner bottom 21 combined with the burner top 24
And a rectifying plate 26 attached to the partition plate 22. Further, the burner top 24 is provided with flame holes 281 and 282 having excellent heat resistance and high-temperature oxidation resistance, and back nets 271 and 272 for preventing flashback and reducing the static pressure of the mixed gas. This burner top 24, back net 271, 27
2. Catalysts for oxidizing unburned gas are carried on the flameholes 281 and 282 in order to suppress the generation of offensive odor during fire extinguishing.

Next, the operation of the above-described conventional liquid fuel combustion apparatus will be described.

First, liquid fuel (kerosene) is pressure-fed to a carburetor 10 by a fuel pump (not shown), is vaporized by heating of a vaporization heater 12, and is supplied as a fuel gas A from a nozzle 14 to a burner bottom 21 of a combustion burner 20. Partition plate 2
2 is injected into the mixing tube 23 composed of In the mixing pipe 23, the fuel gas A is mixed with the primary air B flowing into the fuel gas A to form a mixed gas C. Mixed gas C
Enters a static pressure chamber 25 constituted by a burner top 24 and a partition plate 22, is made uniform by a rectifying plate 26,
After passing through the back nets 271 and 272,
The fuel is ignited by the ignition device 40 and burns. Then, the presence / absence and state of the combustion flame are confirmed by the flame detection means (frame sensor) 50, and the combustion is continued. The carburetor 10, the combustion burner 20, the igniter 40, the flame detecting means 50 and the like are fixed to the mounting box 60.

The heat recovered by the combustion heat recovery unit 11 heats the vaporization chamber of the vaporizer 10 together with the vaporization heater 12. Before the start of combustion, that is, before the combustion flame is formed, the liquid fuel is preheated to a predetermined temperature by the vaporizing heater 12 to become the combustion gas A.

At the time of extinguishing the fire, the fuel pump that has pumped the liquid fuel to the vaporizer 10 is stopped, and the convection blower is also braked and stopped. Mixed gas C remaining in mixing pipe 23 and static pressure chamber 25 of combustion burner 20
Continues to burn on the flame cords 281, 282 of the combustion burner 20. Further, high-pressure residual vaporized gas (vaporized fuel) remains in the vaporizer 10.

[0012] As the mixed gas C remaining in the combustion burner 20 burns, the pressure of the residual vaporized gas in the vaporizer 10 also decreases, so that the ejection pressure from the nozzle 14 of the vaporizer 10 also decreases. Along with this, the suction amount of the primary air B also decreases, so that the power of the combustion flame in the combustion burner 20 also gradually weakens, and the flame detection means 5 via the combustion flame.
The flame current value between 0 and the combustion burner 20 also decreases. When the flame current value becomes equal to or less than a preset value, the solenoid valve 15 of the carburetor 10 operates to close the nozzle 14 of the carburetor 10 to prevent the release of the residual vaporized gas in the carburetor 10. I have.

On the other hand, in the combustion burner 20, the combustion is stopped by closing the nozzle 14 of the carburetor 10, but the combustion is stopped.
A small amount of unburned gas remains in the combustion burner 20, the mixing pipe 23, and the static pressure chamber 25.
4. Back net 271,272, Flame net 281,28
Intermediate products such as aldehydes are generated upon contact with 2 or the like, and an irritating odor is generated. This causes an unpleasant odor generated at the time of fire extinguishing.

[0014]

However, the above-mentioned conventional liquid fuel combustion apparatus has the following problems.

In order to suppress the generation of offensive odor during the fire extinguishing described above, the flame nets 281 and 282 and the back net 2
In the combustion burner 20 formed by carrying a catalyst for oxidizing an unburned gas on the fuel burners 71 and 272, the generation of off-flavors during digestion is suppressed. A transient excessive oxidation reaction occurs on the ropes 281 and 282 and the back nets 271 and 272,
The flame current value between the flame detecting means 50 and the combustion burner 20 is significantly reduced, and the control circuit determines that a misfire or a significant combustion failure has occurred even during combustion, so that combustion cannot be continued. There was something to do.

FIG. 8 shows a correlation diagram of the flame current value during normal combustion and when a transient excessive oxidation reaction occurs.

That is, particularly during weak combustion, if the combustion speed becomes higher than the injection speed of the mixed gas C from the burner flame hole, the combustion position gradually falls and the flame hole rope 28
Approaching 1,282. At this time, the flame net 281
The temperature of the catalyst supported on 282 becomes high, and an excessive oxidation reaction occurs. As a result, the combustion position further lowers, and eventually reaches the lower surfaces of the flame holes 281 and 282. In this case, as shown in FIG. 8, the flame current value sharply decreases, and the control circuit determines that a misfire or significant combustion failure has occurred, stops the combustion, and cannot continue the combustion.

In view of the above-mentioned problems, the present invention can prevent a rapid decrease in flame current value due to a transient excessive oxidation reaction that occurs during combustion, can continue combustion normally, and generate an odor during digestion. It is an object of the present invention to provide a liquid fuel combustion device capable of reducing the amount of liquid fuel.

[0019]

According to a first aspect of the present invention, there is provided a liquid fuel combustion apparatus comprising: a vaporizer for vaporizing a liquid fuel; and a vaporizer for vaporizing the vaporized fuel by the vaporizer. A combustion burner to be burned, a catalyst carried by the combustion burner to oxidize unburned vaporized fuel, flame detection means disposed above the combustion burner for detecting a combustion flame, and an output of the flame detection means. And a control means for controlling combustion by means of a fuel burner, characterized in that an unsupported portion of the catalyst is provided at a position of the combustion burner facing the flame detection means.

According to a second aspect of the present invention, there is provided a liquid fuel combustion apparatus according to the first aspect.
The combustion burner has a plurality of flame holes and a plurality of flame hole networks respectively arranged in the flame holes, and one of the plurality of flame hole networks arranged to face the flame detecting means. The catalyst is not carried on the flame hole network, but the catalyst is carried on the other flame hole network substantially juxtaposed with the one flame hole network.

Further, according to a third aspect of the present invention, in the liquid fuel combustion apparatus according to the second aspect, the shape of the one flame hole network is smaller than that of the other flame hole network. It is characterized by the following.

According to the above configuration, the liquid fuel combustion apparatus according to the first aspect of the present invention has a configuration in which the non-supporting portion of the catalyst is provided at a position facing the flame detecting means of the combustion burner. In the portion excluding the non-supported portion, that is, in the portion where the catalyst of the combustion burner is supported, a transient excessive oxidation reaction occurs, but since the catalyst is not supported in the non-supported portion, the transient Excessive oxidation reaction can be prevented from lowering the combustion position.
As a result, the flame current value is prevented from remarkably lowering due to a transient excessive oxidation reaction. Can be prevented. Moreover, at the time of digestion, the unburned vaporized fuel is decomposed by the oxidation reaction in the portion of the combustion burner supporting the catalyst, thereby reducing the generation of offensive odor.

According to a second aspect of the present invention, there is provided a liquid fuel combustion apparatus according to the first aspect.
The combustion burner has a plurality of flame holes and a plurality of flame hole networks respectively arranged in the flame holes, and one of the plurality of flame hole networks arranged to face the flame detecting means. Since the catalyst is not carried by the flame hole network and the catalyst is carried by the other flame hole network substantially juxtaposed with the one flame hole network, malfunctions can be reliably prevented during combustion, as described above. At the same time, the generation of off-flavors during digestion can be reduced.

Further, according to a third aspect of the present invention, in the liquid fuel combustion apparatus according to the second aspect, the shape of the one flame hole network is smaller than that of the other flame hole network. Therefore, at the time of digestion, many unburned vaporized fuels can be decomposed by oxidizing reaction with the catalyst, and the generation of off-flavors can be further reduced.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A liquid fuel combustion apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view of an essential part of a liquid fuel combustion apparatus according to a first embodiment of the present invention, FIG. 2 is a plan view of an essential part of the liquid fuel combustion apparatus, and FIG. FIG. 3 is an exploded perspective view of the combustion burner shown in FIG. 2.

As shown in FIGS. 1 and 2, the liquid fuel combustion apparatus according to this embodiment comprises a petroleum fan heater and the like, and includes a combustion burner 20 and a carburetor 10 as in the conventional example. It is fixed to the box 60. The combustion burner 20 includes a metal flame hole cord 281
282 is used. As shown in FIG. 3, the combustion burner 20 includes a partition plate 22 sandwiched between a burner top 24 and a burner bottom 21 combined with a burner top 24, and a rectifying plate 26 attached to the partition plate 22.

The burner top 24 has flame holes 281 and 282 excellent in heat resistance and high-temperature oxidation resistance, and a back net 27 for preventing flashback and reducing the static pressure of the mixed gas C.
1, 272 are attached.

Here, the flame holes 2 of the flame holes which do not face the flame detecting means (frame sensor) 50 of the combustion burner 20.
81, the back net 271 carries a catalyst for oxidizing unburned gas (unburned vaporized fuel). Also,
The flame net 282 and the back net 272 of the flame holes facing the flame detection means 50 of the combustion burner 20 do not carry a catalyst for oxidizing unburned gas, and have a shape (specifically, a combustion area). ) Are smaller than the flame net 281 and the back net 271 of the flame holes not facing the flame detecting means 50. Therefore, the rate at which unburned gas contacts the catalyst is increased as compared with the liquid fuel combustion device according to the second embodiment described later. Further, since the flame hole facing the flame detecting means 50 only needs to detect the flame current, it can be further reduced.

The vaporizer 10 includes a vaporization heater 12 for heating the vaporizer 10 to a predetermined temperature, a thermistor 13 for detecting the temperature of the vaporizer 10, and a vaporizer in the vaporizer 10. Nozzle 14 for ejecting the fuel gas A
Is attached. Reference numeral 15 denotes a solenoid valve that operates a needle for opening and closing the nozzle 14.

The operation and effect of the carburetor 10 and the combustion burner 20 of the liquid fuel combustion apparatus configured as described above will be described below. Detailed description is omitted.

The unburned gas generated after the fire is extinguished is brought into contact with the catalyst supported on the flame net 281 and the back net 271 heated to an active temperature by the combustion flame, and is oxidized and burned.

At the time of combustion, a transient excessive oxidation reaction may occur in the back net 271 carrying the catalyst and the flame hole rope 281 particularly during weak combustion, but the back net 272 carrying no catalyst and the flame hole The net 282 does not undergo a transient excessive oxidation reaction during weak combustion. Therefore, there is no remarkable decrease in the flame current value, and a malfunction such as misfire or significant combustion failure is determined by the control circuit via the flame detection means 50 and combustion is stopped, and combustion is continued normally. .

As described above, according to the liquid fuel combustion apparatus of this embodiment, in the combustion burner 20, the oxidation catalyst is supported only on the back net 271 and the flame net 281 of the flame holes not facing the flame detecting means. By doing so, an unpleasant odor can be reduced at the time of fire extinguishing, and a remarkable decrease in flame current value does not occur at the time of combustion, so that normal combustion can be continued.

FIG. 4 is an exploded perspective view of a combustion burner of a liquid fuel combustion apparatus according to a second embodiment of the present invention. In the present embodiment, only points different from the above-described first embodiment will be described.

In the liquid fuel combustion apparatus according to the present embodiment, the flame nets 281 and 282 and the back nets 271 and 272 have substantially the same shape.

In the liquid fuel combustion device, since the ratio between the one carrying the catalyst and the one not carrying the catalyst is uniform, the generation of an unpleasant odor is prevented during digestion as in the liquid fuel combustion device according to the first embodiment. Although it is not possible to reduce the generation of off-flavors, it is also necessary to reliably prevent malfunction during combustion, as in the case of the liquid fuel combustion apparatus according to the above-described embodiment, and to continue normal combustion particularly during weak combustion. Can be.

[0038]

As described above, according to the liquid fuel combustion apparatus of the present invention, since the catalyst is not supported in the non-supporting portion, a transient excessive oxidation reaction occurs during combustion,
The combustion position does not decrease. As a result, the flame current value is prevented from remarkably lowering due to a transient excessive oxidation reaction. Can be prevented. Therefore, it is possible to continue the combustion normally especially at the time of the weak combustion.

Further, at the time of digestion, the unburned vaporized fuel is decomposed by oxidizing reaction at the portion of the combustion burner supporting the catalyst, thereby reducing the generation of offensive odor.

Further, according to the liquid fuel combustion apparatus of the third aspect of the present invention, during digestion, a large amount of unburned vaporized fuel can be decomposed by oxidizing reaction with the catalyst to further reduce the generation of offensive odor. Can be.

[Brief description of the drawings]

FIG. 1 is a front view of a main part of a liquid fuel combustion device according to a first embodiment of the present invention.

FIG. 2 is a plan view of a main part of the liquid fuel combustion device according to the first embodiment of the present invention.

FIG. 3 is an exploded perspective view of a combustion burner of the liquid fuel combustion device according to the first embodiment of the present invention.

FIG. 4 is an exploded perspective view of a combustion burner of a liquid fuel combustion device according to a second embodiment of the present invention.

FIG. 5 is a front view of a main part of a conventional liquid fuel combustion device.

FIG. 6 is a plan view of a main part of a conventional liquid fuel combustion device.

FIG. 7 is an exploded perspective view of a combustion burner of a conventional liquid fuel combustion device.

FIG. 8 is a correlation diagram between a flame current and a combustion state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Evaporator 20 Combustion burner 281,282 Flame line 271,272 Back net 50 Flame detecting means

Claims (3)

[Claims] 1. A vaporizer for vaporizing a liquid fuel, a combustion burner for burning the vaporized fuel vaporized by the vaporizer, a catalyst carried on the combustion burner for oxidizing unburned vaporized fuel, and the combustion burner. A liquid fuel combustion device, comprising: a flame detecting means disposed above the flame detecting means for detecting a combustion flame; and a control means for controlling combustion based on an output of the flame detecting means. A liquid fuel combustion apparatus, wherein a non-supporting portion of the catalyst is provided at a position facing the liquid fuel combustion device. 2. The combustion burner has a plurality of flame holes and a plurality of flame hole networks respectively arranged in the flame holes, and faces the flame detecting means in the plurality of flame hole networks. 2. The liquid fuel according to claim 1, wherein the catalyst is not carried by one of the arranged flame networks, and the catalyst is carried by the other flame network substantially juxtaposed to the one of the flame networks. Combustion equipment. 3. The liquid fuel combustion apparatus according to claim 2, wherein the shape of the one flame hole network is smaller than that of the other flame hole network.