JPH11141810A - Liquid fuel combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To elongate the life of an ignition heater while contriving the reduction of smell arising at ignition by operating an ignition heater. SOLUTION: When extinguishing action is started, the supply of fuel to a burner 6 is interrupted, and flame decreases gradually. When a specified waiting time passes and the flame disappears, a current is supplied to an ignition heater 17. The ignition heater 17 comes to high temperature, and uncombusted gas left within the burner 6 turns into gas with little smell, and it is deodorized.

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 apparatus such as a petroleum fan heater capable of reducing the generation of odor when extinguishing a fire.

[0002]

2. Description of the Related Art Conventionally, in a liquid fuel combustion apparatus such as a petroleum fan heater which vaporizes and burns liquid fuel such as kerosene, kerosene in a fuel tank is sent to a vaporizer to be vaporized and vaporized. The fuel is ejected to the burner by the nozzle of the carburetor, and is mixed with air to form a mixed gas. Then, the mixed gas is ignited by an igniter (ignition heater) to form a flame on the burner and is burned in the combustion chamber.

To extinguish a fire, the supply of fuel to the burner is stopped, and at the same time, the kerosene in the carburetor is returned to the fuel tank, and the combustion is terminated. At this time, the unburned mixed gas remaining in the burner flows out of the combustion device without burning (reacting), and thus remains as an odor at the time of fire extinguishing.

[0004] In order to solve this problem, there is a method in which a catalyst is carried on a burner and the unburned gas is reacted to produce an odorless gas. There is also a method of completely burning (reacting) the unburned gas after fire extinguishing to reduce the generation of odor. For example, JP-A-58-160718 and JP-A-60-2375.
No. 2, JP-A-61-161325, JP-A-61-16325
Japanese Unexamined Patent Application Publication No. 1-223415 and Japanese Unexamined Patent Application Publication No. Sho 62-119362 disclose a technique for energizing an ignition heater at the time of fire extinguishing to burn unburned gas.

[0005]

However, when the fire extinguishing operation is started, the ignition heater has been exposed to the flame, and thus has a high temperature of 300 ° C. or more. For this reason,
If the ignition heater is energized at the same time as the ignition operation, the temperature may rise excessively more than necessary, which may shorten the life of the ignition heater.

[0006] In view of the above, an object of the present invention is to provide a liquid fuel combustion apparatus that operates the igniter to reduce the odor generated at the time of fire extinguishing, and that extends the life of the igniter.

[0007]

Means for Solving the Problems According to the present invention, when a fire extinguishing operation is performed by stopping the supply of fuel to a burner and extinguishing a flame, a predetermined standby time has elapsed after the start of the fire extinguishing operation. A control unit is provided to control the igniter to operate or to provide a detection unit for detecting fire extinguishing of the burner, and to control the igniter to operate after the fire extinguishing is detected.

Accordingly, the igniter can be operated after the flame has completely disappeared from the burner, so that an abnormal rise in the temperature of the igniter can be prevented, and the life of the igniter can be extended.
In addition, the unburned gas remaining in the burner is burned until the igniter is activated, and the igniter reacts the unburned gas to a gas with low odor until the igniter is activated. can do.

Here, the standby time of the igniter is set based on the combustion amount before the start of the fire extinguishing operation. Further, the operating time of the igniter may be set based on the combustion amount before the start of the fire extinguishing operation. As a result, the igniter does not operate when it is exposed to the flame, and the harmful effect of operating the igniter until an unnecessary time can be eliminated, so that the odor can be rationally deodorized.

[0010] If a catalyst for promoting the reaction of unburned gas is carried on the igniter, the deodorizing effect can be further enhanced by its action.

[0011]

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 accompanying drawings when applied to a liquid fuel vaporization type combustion apparatus such as a petroleum fan heater.

1 to 3, reference numeral 1 denotes a fuel tank for containing kerosene 2 as a liquid fuel; 3 a vaporizer for vaporizing the kerosene 2; 4 an electromagnetic pump for feeding the kerosene 2 to the vaporizer 3 through an oil supply pipe 5; Reference numeral 6 denotes a burner for mixing the vaporized kerosene 2 with air and burning it, and reference numeral 7 denotes a combustion chamber.

The vaporizing chamber of the vaporizer 3 is provided with a vaporizing element 8 made of a wire mesh, porous metal or the like, and a vaporizing heater 9 made of a ceramic heater such as silicon nitride. Nozzle 11 that jets out toward the suction hole 10 is provided. Further, a heat transfer body 12 for transmitting radiant heat from the burner 6 to the vaporizer 3 is integrally formed, and
Is arranged above the mesh-shaped flame port 13.

The nozzle 11 is opened and closed by a needle 14, and an electromagnetic valve 15 for controlling the opening and closing of the needle 14 is provided. Further, a return pipe 16 is provided to return the kerosene 2 in the vaporization chamber to the fuel tank 1 when the nozzle 11 is closed.

An ignition heater 17 as an igniter for igniting and burning a mixed gas of kerosene 2 and air injected and supplied to the burner 6 is disposed immediately above the flame port 13 of the burner 6. The ignition heater 17 is made of a ceramic heater such as silicon nitride, and is a support member 1 fixed to a main body frame 18.
9 attached. Further, by supporting a catalyst such as platinum (Pt) or nickel on the surface of the ignition heater 17, the reaction of the unburned gas can be promoted and the generation of odor can be suppressed.

A flame sensor 20 for detecting the combustion state of the burner 6 is provided alongside the ignition heater 17. The frame sensor 20 uses a frame rod whose resistance value changes according to the combustion state. That is, if an alternating current is applied using the frame rod and the conductive burner 6 as a pair of electrodes, a flame corresponding to the resistance value flows due to the action of ions present in the flame. Detect whether or not.

The electromagnetic pump 4, the vaporizing heater 9, the electromagnetic valve 15, the ignition heater 17, and the frame sensor 20 are:
As shown in FIG. 4, the control unit 21 is connected to a control unit 21 composed of a microcomputer. The operation and extinguishing operations are performed by turning on and off the operation switch 22 and an output signal from the frame sensor 20, and a temperature signal from a temperature sensor (not shown). Each operation is controlled so as to reach a temperature set based on.

In the liquid fuel combustion apparatus configured as described above, when the operation switch 22 is turned on, the electromagnetic pump 4
As a result, the kerosene 2 in the fuel tank 1 is sent into the vaporizer 3 through the oil feed pipe 5, is vaporized and vaporized through the vaporizing element 8 heated by the vaporizing heater 9, and is ejected toward the burner 6 by the nozzle 11. .

The vaporized kerosene 2 is mixed with air in a burner 6 to form a mixed gas, ignited by an ignition heater 17, ignited on a flame port 13, and a flame is generated. To start. Then, when the flame sensor 20 detects the occurrence of the flame, the energization of the ignition heater 17 is stopped, and the driving of the vaporizing heater 9 and the electromagnetic pump 4 is controlled to continue the combustion while detecting the combustion state thereafter. .

At the time of fire extinguishing, the fire extinguishing operation is started when the operation switch 22 is turned off. First, the electromagnetic pump 4 is stopped, and then the nozzle 11 is closed by the electromagnetic valve 15 to stop energizing the vaporization heater 9. At the same time, the kerosene 2 in the vaporization chamber of the vaporizer 3 is returned into the fuel tank 1 by the return pipe 16 to terminate the combustion.

Then, when the fire extinguishing operation is started, the ignition heater 17 is energized. Normally, a ceramic heater such as silicon nitride, which rapidly rises in temperature, is used as the ignition heater 17, so that even if a household power supply of 100 V is energized, 50 seconds can be obtained in a few seconds.
The temperature can be sufficiently raised to about 0 ° C. Therefore,
Even if the nozzle 11 is closed by the solenoid valve 15 and the flame is extinguished from the flame opening 13 of the burner 6, the ignition heater 17 can be maintained at a high temperature, and the unburned gas remaining in the burner 6 is discharged by the flame of the burner 6. When the gas is generated from the mouth 13, it can be reacted with a gas having a small odor.

When the fire extinguishing operation is started, the temperature of the ignition heater 17 is high because it is exposed to the flame. Therefore, a predetermined standby time is provided, and the operation of the ignition heater 17 is controlled so that the power is supplied after this time has elapsed.

That is, when the fire extinguishing operation is started, the flame of the burner port 13 of the burner 6 gradually decreases, and the flame disappears (extinguishes) in about 5 to 30 seconds. Also, after the flame has extinguished,
Since unburned gas is generated for 0 to 30 seconds, it is sufficient for the unburned gas to react even if the ignition heater 17 is energized after the flame is extinguished, thereby preventing the generation of odor.

By the way, the time until the flame disappears naturally depends on the amount of combustion immediately before performing the fire extinguishing operation. In other words, when the maximum combustion occurs immediately before performing the fire extinguishing operation, the flame in the burner port 13 of the burner 6 decreases, and it takes about 30 seconds until the flame disappears. For example, the larger the amount of combustion, the longer the time. Also, the amount of fuel supplied varies depending on the amount of combustion, and the larger the amount of combustion, the greater the amount of residual unburned gas.

Therefore, the control unit 21 stores the combustion amount during operation in a memory or the like at any time based on the output signal of the frame sensor 20, and sets the standby time based on the combustion amount immediately before the fire extinguishing operation. The operating time of the ignition heater 17 is also set. Specifically, as shown in Table 1, the standby time and the operation time are lengthened as the combustion amount increases, and the standby time and the operation time are shortened as the combustion amount decreases.

[0026]

[Table 1]

This makes it possible to energize the ignition heater 17 after the flame is extinguished without fail, so that the temperature of the ignition heater 17 can be prevented from rising more than necessary, and the life of the ignition heater 17 can be extended. be able to. Moreover, since the ignition heater 17 is operated only for a time enough to cause all remaining unburned gas to react, wasteful consumption of electric power can be prevented.

In the above configuration, the ignition heater 17 is controlled based on the amount of combustion. However, the flame sensor 20 is used as a detecting unit for detecting the extinction of the burner 6, and the ignition heater 17 is controlled based on the actual flame state. May be controlled. That is, the detection of the state of the flame is performed by the frame sensor 20 and the burner 6.
It is done by detecting the current flowing between
As shown in FIG. 5, the frame detection circuit can be equivalently represented by a diode 23 and a resistor 24 connected in series.

In the case of normal combustion, this equivalent resistance value is 2 MΩ or less. When the fire extinguishing operation is started and the electromagnetic pump 4 is stopped, the flame in the burner port 13 of the burner 6 gradually decreases, and this equivalent resistance value increases. When the fire resistance exceeds 6 to 7 MΩ, it can be determined that the flame has disappeared.

From this, when the equivalent resistance value becomes equal to or more than a certain value, for example, 6 MΩ or more by the frame sensor 20 after starting the fire extinguishing operation, it is determined that the fire has been extinguished, and the ignition heater 17 is energized. Further, after several tens of seconds, for example, 30 seconds, the power supply to the ignition heater 17 is stopped. Therefore, since the extinction of the flame can be accurately detected, it is possible to prevent the ignition heater 17 from being energized while being exposed to the flame and to prevent an excessive rise in temperature, and to more reliably extend the life.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that many modifications and changes can be made to the above-described embodiment within the scope of the present invention. For example, an ignition heater made of a ceramic heater has a characteristic that a specific resistance value of the heater itself changes with temperature. Therefore, by using this characteristic to detect the resistance value of the ignition heater, after the fire extinguishing operation starts, when the temperature of the ignition heater drops to a certain temperature, it is determined that the flame has extinguished, and the energization is started. You may. Further, a time required to decrease to a certain temperature is measured, and an operation time is set based on the time. This makes it possible to make all the unburned gas react while eliminating the odor while extending the life of the ignition heater.

[0032]

As is apparent from the above description, according to the present invention, the igniter is controlled to operate after a predetermined standby time has elapsed since the start of the fire extinguishing operation, or the igniter is operated after the fire extinguishing of the burner is detected. Since the ignition is controlled, the igniter is not operated in a state where the flame exists immediately after the start of the fire extinguishing operation, so that an abnormal rise in the temperature of the igniter can be prevented, and the life of the igniter is not impaired. Moreover, even when the igniter is operated in this manner, the unburned gas generated after the flame is extinguished can be reacted, and the odor generated due to the fire extinguishing operation can be reliably reduced.

Since the standby time or operating time of the igniter is set based on the amount of combustion before the start of the fire extinguishing operation, the igniter is not exposed to the flame, does not generate an excessive temperature rise, and has a long service life. Can be achieved. Moreover, since it is possible to eliminate unnecessary operation of the igniter after the deodorization is completed,
Deodorization can be performed efficiently.

By supporting the catalyst on the igniter, the reaction of the unburned gas is promoted, and the deodorizing effect can be further enhanced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of a liquid fuel combustion device according to an embodiment of the present invention.

FIG. 2 is a front view of the same main part.

3A is a plan view of a burner portion, and FIG. 3B is a front view of the same.

FIG. 4 is a control block diagram.

FIG. 5 is a detection circuit diagram of a frame sensor.

[Explanation of symbols]

 3 carburetor 6 burner 17 ignition heater 20 frame sensor 21 control unit

Claims (5)

[Claims] 1. A fire extinguisher comprising: a vaporizer for vaporizing liquid fuel; a burner for burning the vaporized fuel; and an igniter for igniting the burner, and by stopping supply of fuel to the burner. In a liquid fuel combustion device that performs an operation, a control unit that activates the igniter after a predetermined standby time has elapsed from the start of the fire extinguishing operation is provided. 2. The liquid fuel combustion apparatus according to claim 1, wherein the control unit sets the standby time of the igniter based on the amount of combustion before the start of the fire extinguishing operation. 3. The liquid fuel combustion device according to claim 1, wherein the control unit sets the operation time of the igniter based on a combustion amount before the start of the fire extinguishing operation. 4. A fire extinguishing method comprising: a vaporizer for vaporizing liquid fuel; a burner for burning the vaporized fuel; and an igniter for igniting the burner, and stopping the supply of fuel to the burner. A liquid fuel combustion device that performs an operation, wherein a detection unit that detects the extinguishing of the burner and a control unit that activates the igniter after the detection of the extinguishing are provided. 5. The igniter carries a catalyst that promotes the reaction of unburned gas.
A liquid fuel combustion device as described.