JPH10311529A - Liquid fuel combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify control of a fire extinguishment sequence and to perform control of stable fire extinguishment being not influenced by a combustion mode by a method wherein after a combustion device is transferred to a given combustion amount once, a blower for combustion is controlled for deceleration through a specified sequence. SOLUTION: In a liquid combustion device, liquid fuel supplied by a fuel supply device 23 alternately based on an ON-signal and an OFF-signal is vaporized by a vaporizer 21, the vaporized gas is mixed with air for combustion from a blower 24 for combustion, and mixture gas is ignited by an ignition device 22 at a flame forming part to effect combustion. In this case, after combustion is transferred to a given combustion amount during fire extinguishment operation by an operation off switch 14, for a specified time, a control device 10 outputs a deceleration signal to control the blower 24 for combustion after a lapse of a given time starting from an OFF-signal to the fuel supply device 23. This constitution simplifies control of a fire extinguishment sequence and performs control of stable fire extinguishment not influenced by a combustion mode.

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 and a forced supply / exhaust type hot air heater for vaporizing and burning liquid fuel in a vaporizer, and more particularly to a liquid fuel in a fire extinguishing operation. The present invention relates to control of a combustion blower of a fuel combustion device.

[0002]

2. Description of the Related Art As a control of a fire extinguishing operation of a conventional liquid fuel combustion apparatus, as disclosed in Japanese Patent Application Laid-Open No. 2-197760, at the time of a combustion stop operation, an operation state of a fuel supply apparatus (more specifically, an electromagnetic pump) is controlled. Generally, the supply of the liquid fuel is immediately stopped regardless of the manner.
In particular, according to the heater disclosed in the above publication, the supply of liquid fuel is stopped, and at the same time, the combustion air is fixed to a weak air flow, so that the residual heat of the burner causes the fuel supply device (specifically,
The nozzle is heated to increase its temperature, making it easier to drip fuel.

[0003] Japanese Patent Application Laid-Open No. 6-94235 discloses that
In order to reduce the unburned gas mixture of combustion air and vaporized fuel and reduce the odor at the time of fire extinguishing, the reduction rate of combustion air approaches the reduction rate of fuel or when the fuel decreases to the specified amount. A technique for stopping the supply of combustion air is disclosed.

However, even in the above control mode,
At the time of fire extinguishing, unburned gas (hereinafter referred to as unburned gas) of the mixed gas is generated, and this unburned gas is released to the outside of the body of the liquid fuel combustion device, and it is understood that the user feels it as smell. ing.

Therefore, in order to minimize the generation of unburned gas at the time of fire extinguishing when a fire extinguishing operation is instructed, it is necessary to appropriately stop the fuel supply / sending device (particularly the pump) and then apply a brake to the combustion blower. By controlling, before the flame disappeared, that is, the generation of unburned gas was suppressed, and a liquid fuel combustion device in which the concentration of the mixed gas immediately before the misfire was appropriately adjusted so as to have an appropriate value for burning was devised. I have.

According to this control mode, it is possible to completely burn out the mixed gas that has accumulated in the space from the vaporizer to the flame forming section when extinguishing the fire. The problem that fuel gas is discharged is eliminated, and the odor at the time of fire extinguishing can be suppressed.

[0007]

However, in such a liquid fuel combustion device, when the fuel supply device is stopped, the combustion state of the equipment (strong combustion state or weak combustion state,
Or, depending on the number of revolutions of the combustion blower at that time)
Since the time from when the fuel supply device is stopped to when the fire is completely extinguished differs (for example, 2500 kcal / h)
With the combustion device of the above, about 0.2 seconds for strong combustion and about 0.2 seconds for weak combustion.
8 seconds), there is a disadvantage that the control of the fire extinguishing operation is complicated because the start timing and the braking time of the brake control of the combustion blower at the time of the fire extinguishing operation vary depending on the combustion state.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks. At the time of a fire extinguishing operation, the combustion device is temporarily shifted to a predetermined combustion amount regardless of the combustion state, and thereafter,
It is an object of the present invention to provide a liquid fuel combustion apparatus that simplifies the control of a fire extinguishing sequence by performing deceleration control of a combustion blower in a fixed sequence, and realizes stable fire extinguishing control that is not affected by a combustion mode.

[0009]

That is, according to the present invention, the liquid fuel supplied by the fuel supply device which operates based on the ON signal and the OFF signal supplied alternately is vaporized by the vaporizer. In a liquid fuel combustion system in which the vaporized gas is mixed with combustion air from a combustion blower, and the mixed gas is ignited by an ignition device in a flame forming unit and burned, when the fire is extinguished by a run-off switch, combustion is performed. And a control device for outputting a deceleration signal for decelerating the combustion blower for a predetermined time after a predetermined time has elapsed from the supply of the OFF signal to the fuel supply device after the shift to a predetermined combustion amount.

Further, according to the present invention, the liquid fuel supplied by the fuel supply device which operates based on the ON signal and the OFF signal supplied alternately is vaporized by the vaporizer, and the vaporized gas is discharged. Mix with combustion air from combustion blower,
In a liquid fuel combustion device in which the mixed gas is ignited by an ignition device in a flame forming unit and burned, at the time of a fire extinguishing operation by an operation-off switch, the combustion is shifted to a predetermined combustion amount, and then an off signal to the fuel supply device is output. A control device is provided which outputs a deceleration signal for controlling deceleration of the combustion blower after a predetermined time from the supply, and outputs a drive signal of the combustion blower before the combustion blower does not stop.

Further, the present invention according to claim 3 is characterized in that, when it is detected that any abnormality has occurred in the liquid fuel combustion device, the control device immediately shifts to a fire extinguishing operation.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic perspective view showing an entire configuration of an oil fan heater as a hot air heater according to an embodiment of the present invention, and FIG. 2 is a control means for controlling a liquid fuel supply device, a combustion fan and a convection fan. FIG. 3 is a block diagram of a control device centered on FIG. 3, FIG. 3 is a flowchart schematically showing the control operation of the control means shown in FIG.
3 is a main flowchart of the present invention showing an outline of the fire extinguishing operation sequence of FIG. 3, and FIG. 5 is a time chart showing an outline of signal processing in the fire extinguishing operation sequence of FIG.

In FIG. 1, reference numeral 1 denotes an outer case constituting a main body of the oil fan heater H, and 2 denotes an outlet for blowing out hot air. There are a blower for combustion and a blower for convection.

The fuel is supplied from the fuel tank to the combustion chamber to a carburetor and a burner head as a flame forming portion located above the carburetor (collectively referred to as a burner or a combustion portion). Fuel supply device including an electromagnetic pump, a fuel discharge nozzle, an ignition plug (igniter) as an ignition device, a flame sensor and a carburetor as an ignition and flame detection device for detecting a state of a flame formed in a burner head A combustion device composed of a vaporization heater and the like built in the device is disposed.

Reference numeral 3 denotes an openable and closable lid for inserting and removing a cartridge tank which is detachably set to a fuel tank (not shown). Reference numeral 4 denotes a switch for instructing the operation of the oil fan heater H by control means to be described later. And an operation panel as an operation unit on which operation means such as lamps and liquid crystal display means are arranged. The operation panel is provided on the upper surface of the outer case 1.

In the lower part of the back surface of the oil fan heater H, electric components such as a control device 10 mounted on an operation board or a control board disposed directly below the operation panel 4, a combustion device, a combustion fan, and a convection fan. When a power cord for supplying power to the power supply is wired and a plug of the power cord is inserted into an outlet, power is supplied to at least the control device 10. Here, an operation of inserting the plug into the outlet is performed. This is called power-on, which is distinguished from the operation switch-on operation.

Next, with reference to FIG. 2, a schematic configuration of a control device 10 centering on a control means 11 for controlling an ignition device, a liquid fuel supply device, a combustion fan and a convection fan will be described.

In FIG. 2, reference numeral 10 denotes a control device mainly including a control means 11 which is a main component of the present invention. The control means 11 is constituted by a microcomputer having a timer and a ROM and a RAM as storage means. ing. The control means 11 outputs a control signal for controlling the operation of various loads based on the input signal. Reference numeral 12 denotes an EEPROM as a writable storage means connected to the control means 11 via a signal line. is there. In FIG. 2, the EEPR
Although the OM is expressed as if it is separate from the control means 11, this is not limited to a separate one.
M may be incorporated in the control means 11.

Various switches 13 to 15 provided on the operation panel 4 and various sensors 16 to 20 provided at appropriate positions are connected to the input side of the control means 11, and the output side of the control means 11 is connected to an electric motor. Parts, ie, a vaporization heater 21 incorporated in a burner (specifically, a vaporizer), a spark plug (igniter) 22 as an ignition device, and a part of a fuel supply device for supplying fuel from a fuel tank to a burner (combustion unit). An electromagnetic pump 23, a blower 24 for supplying combustion air to a combustion section, and a convection fan for sucking outside air into an outer case 1 and exchanging heat with combustion gas generated in a combustion chamber and supplying the air to an outlet 2. 25 are connected.

The various switches connected to the input side of the control means 11 include an operation-on switch 13 for instructing the start of operation of the oil fan heater H and extension of the combustion time, an operation-off switch 14 for instructing stop of the operation, and There is another switch 15 for instructing other functions, such as a second-speed ignition and a timer.

In this embodiment, the operation switch 1 is turned off.
4 has a function of controlling the operation of each of the electromagnetic pump 23 and the combustion blower 24 during the fire extinguishing operation to suppress and control the generation of unburned gas. As a specific example, another switch may be provided independently of the operation switch 14. However, in order to reduce the number of switches on the operation panel, it is preferable that the switch is also used. Performing the fire extinguishing operation in this control mode enhances the function as a warm air heater.

The various sensors include a burner thermistor 16 provided below the burner (more specifically, a vaporizer) for detecting the temperature of the burner, and that a flame is formed in the burner head, that is, that the ignition and the burner head are formed. Frame sensor 17 as a flame detection device for detecting the state of the flame
Rotation speed sensor 1 for detecting the rotation speed of combustion blower 24
8, a liquid level sensor 19 for detecting the presence or absence of liquid fuel such as kerosene stored in the fuel tank at a predetermined level or more, and the outside air sucked into the exterior case 1 provided near the suction port (not shown) (that is, There is a room temperature sensor 20 that detects the temperature of (room air).

With the above configuration, each operation process of the control means 11 will be described with reference to FIGS.

First, at step S1, the operation switch 13 is turned on.
Is turned on and an operation start is instructed, the operation lamp is turned on or the operation mode text is displayed on the liquid crystal display unit in step S2, and the energization to the vaporization heater (for example, a sheath heater) 21 is started in step S3. In S4, it is determined whether the temperature of the vaporizer (specifically, the burner body) is a temperature suitable for the ignition operation (for example, a temperature range of 250 to 270 ° C.), and the energization control of the vaporization heater 21 is continued until the temperature reaches the proper temperature. When the temperature reaches an appropriate temperature, the combustion blower (specifically, burner motor) 24 is driven in step S5.

Next, in step S6, the rotation speed sensor 1
It is determined whether or not the rotation speed of the burner motor 24 detected in Step 8 has reached a predetermined rotation speed (for example, 1100 rpm).
The operation shifts to S16. If the number of revolutions reaches the specified number of revolutions, the ignition operation is performed in Step S7. In Step S8, it is determined whether or not the ignition has been performed based on the flame current detected by the flame sensor 17, and in the following Step S9. It is determined whether the combustion is normal.

If it is determined in step S8 that the fuel is not ignited, or if it is determined in step 9 that the combustion is not normal, the operation proceeds to steps S17 to S19. An automatic change operation of the combustion amount is started to set the combustion mode or the set room temperature based on the combustion mode.

In the next step S11, it is determined based on the flame current detected by the flame sensor 17 whether or not the state of the flame at the set combustion amount is normal. The operation shifts to operation, and if it is normal, it is determined in step S12 whether or not the operation switch 14 has been operated.

Thereafter, the operations of steps S10 to S12 are repeated until the power-off switch 14 is operated. If the power-off switch 14 is operated, the fire extinguishing operation is performed in the next step S13, and the combustion stop operation is performed in step S14. Upon completion, the operation of the oil fan heater H stops.

If it is determined in step S6 that the rotation speed of the burner motor 24 is abnormal, error processing of the burner motor 24 is executed in step S15. In this case, the operation does not shift to the ignition operation until the abnormality is eliminated. Then, when the user operates the operation-off switch 14 and the operation-on switch 13 in step S16, the control process returns to step S3.

Step S8 or step S9
If the normal flame is not detected within the ignition trial period (for example, 23 seconds) (this is referred to as an ignition error), a mis-ignition process is executed in step S17.

In the following step S18, the convection blower 25
(Fan motor) in step S19
4 (burner motor), the drive signal is stopped, and the ignition sequence is terminated. Then, when the user operates the operation-off switch 14 and the operation-on switch 13 in step S20, the control process returns to step S3.

If it is determined in step S11 that the fire has occurred but the fire has been extinguished in the course of changing the amount of combustion (this is referred to as halfway fire extinguishing), a process of halfway fire extinguishing is executed in step 21. Subsequently, the drive signal is stopped to stop the convection blower 25 in step S22 and the combustion blower 24 in step S23, respectively, and the combustion amount control sequence ends. When the user operates the operation switch 14 and the operation switch 13 in step S24, the control process returns to step S3. Here, an example of the error processing, the mis-ignition processing, and the mid-fire extinguishing processing will be described. The energization of the vaporization heater 21 is stopped, and the operation lamp blinks or the operation mode text on the liquid crystal display unit blinks. The abnormality is indicated by displaying a symbol (for example, E6) indicating a rotation speed abnormality of the burner motor 24, a symbol (for example, E1) indicating misfiring, and a symbol (for example, E2) for extinguishing the fire as the details of the abnormality.

Next, referring to FIG.
A more detailed operation of the fire extinguishing operation by the operation off switch 14 will be described.

First, in step S30, the presence or absence of a fire extinguishing signal (combustion off signal) is detected, and combustion is continued until the off signal is detected. When the off signal is detected, it is determined in step S31 whether the signal is an off signal due to the operation of the operation switch 14 or an off signal due to any other cause (for example, when a device abnormality such as misfiring occurs). .

In the case where the operation switch 14 is operated,
When it is determined that the signal is a normal fire extinguishing signal, the combustion of the device is shifted to a preset combustion amount in step S32 (the rotation speed of the combustion blower 24 is changed. In this case, the electromagnetic pump 23 is changed according to the rotation speed of the combustion blower 24). Also changes the drive pulse signal, and the supply amount of the liquid fuel changes). If it is recognized in step S33 that the combustion amount has reached a predetermined level (fixed point) (for example, the rotation speed of the combustion blower 24 is monitored by the rotation speed sensor 18), a pump signal (for the electromagnetic pump 23) is generated in step S34. It is determined whether or not the on-time output (T2 in FIG. 5) of the drive pulse signal) has been completed.
The combustion operation is continued at the shifted combustion amount until the end of the im output.

When the on-time output of the pump signal is completed, the driving of the electromagnetic pump 23 is stopped in step S35, while the combustion fan 24 (and the convection fan 2) is stopped.
The driving signal (specifically, the phase control signal) to 5) is stopped, and a fire extinguishing sequence for performing the deodorizing operation is started.

Here, as shown in the time chart of FIG. 5, the change in the rotation speed of the combustion blower 24 when the combustion amount is shifted to the fixed point is controlled to reduce the rotation speed, that is, the combustion amount is reduced. Although the case is shown, the combustion operation when the operation off switch 14 is operated is, for example, a weak combustion,
In addition, for example, when the fixed-point combustion amount is set in the middle between the strong combustion and the weak combustion, the rotation speed of the combustion blower by the operation of shifting the combustion amount is controlled to increase. In the present embodiment, when the transition of the combustion amount is completed during the off time (T1-T2),
The combustion state shifted at that time is continued, and this off t
When the im period ends and the next on time ends, the drive signal of the combustion amount blower 24 is stopped.

Next, in step S36, a predetermined time A according to the transferred combustion amount is set in a timer of the control means 11. This predetermined time A corresponds to the start of the fire extinguishing sequence,
That is, a stop time for stopping the output of the phase control signal to both the blowers from the supply of the OFF signal of the electromagnetic pump 23,
During this time, both fans operate by inertia, and the rotation speed gradually decreases.

Next, in step S37, it is determined whether or not a predetermined time A has elapsed. The rotation operation by inertia continues until the predetermined time A has elapsed. When the predetermined time A has elapsed, a deceleration signal, which will be described later, is executed in step S38. To output both blowers 2
The deceleration control of steps 4 and 25 is started, and in the subsequent step S39, a fixed time B is set as a deceleration time. Step S4
At 0, it is determined whether or not a predetermined time B has elapsed.
The deceleration control is continued until elapses, and when the predetermined time B elapses, the drive signals of the combustion fan 24 and the convection fan 25 are supplied again (ie, re-driven) in the next step S41.
Then, the process proceeds to step S14. Note that the starting point of the time until the re-drive signal is stopped is set at the time when the operation switch 14 is operated, and after a lapse of time C (this is referred to as a post-purge time) larger than the time A + B from this starting point. Control is performed so that both blowers 25 are stopped.

Here, the fixed time B is set to the time when the combustion blower 24
Forcibly reduce the number of revolutions (ie, brake control)
Thus, for example, the time (deceleration time) for outputting a signal (deceleration signal) that has been subjected to half-wave rectification, and this constant time B is also the same as the predetermined time A, and corresponds to the combustion amount transferred after the operation of the operation switch 14. The corresponding time is set.

As described above, by stopping the phase control signal of the combustion blower 24, the rotation speed of the blower 24 gradually decreases due to the inertial force. However, after a predetermined time A from when the pump signal is turned off, the combustion is stopped. By controlling the brake of the blower 24 for use, the reduction speed of the rotation speed of the blower 24 for combustion is increased, and the concentration of the mixed gas can be set to an appropriate state in which the concentration of the mixed gas is easily burned just before misfire during the fire extinguishing operation.

In addition, when the fire extinguishing operation is performed, the fire extinguishing sequence is executed after shifting to the predetermined amount of combustion once in any combustion mode. And convection blower 2
The time for stopping the drive signal in 5) (ie, the predetermined time A) and the time for performing the deceleration control (ie, the fixed time B) are the amount of combustion (the mixture of fuel and combustion air) immediately before the fire extinguishing command is issued. Since it can be uniquely set regardless of the mixing ratio), the control of the combustion blower 24 (and the convection blower 25) is extremely simplified, and the optimum value can always be set.

Therefore, regardless of the operating condition (ie, the amount of combustion air) of the combustion blower 24 for supplying combustion air immediately before extinguishing, accurate deceleration control can be realized at all times. In addition to suppressing the excess, it is possible to completely burn out the mixed gas regardless of the fire extinguishing operation in any combustion mode, so that the amount of unburned gas generated can be more suitably suppressed than the conventional fire extinguishing operation. become.

Further, since the combustion blower 24 and the convection blower 25 are driven again after the elapse of the predetermined time B, it is possible to immediately shift to the post-purge operation after the misfire. The post-purge is to cool the combustion part, a heat shielding plate (for example, a shelter) and a liquid fuel supply device (specifically, a nozzle) after a fire extinguishing operation (specifically, a misfire), and to collect unburned gas remaining in the combustion part. Is a blowing operation for discharging air. However, in the present embodiment, as shown in FIG. 5A, the post-purge time C is measured starting from the time when the operation switch 14 is operated.

On the other hand, in step S31, the operation switch 1
If it is determined that the signal is a fire extinguishing signal due to an operation other than the operation 4 (for example, a device abnormality), the electromagnetic pump 23
Is started, that is, a so-called fire extinguishing sequence at the time of occurrence of an abnormality is started, and the process proceeds to step S14. By the way, in the fire extinguishing sequence at the time of occurrence of the abnormality, if the details of the abnormality are separately displayed, the user is kind to the user.

As shown in the time chart of FIG. 5, when the error signal is generated at the same time as described above, the ON signal of the electromagnetic pump 23 is immediately stopped regardless of the combustion mode. Is done. The post-purging time is also C as shown in FIG. 5A, as shown in FIG. 5B, and the amount of combustion air during this post-purging is fixed.

As described above, when the operation switch 14 is operated, first, the combustion is shifted to a predetermined combustion amount.
This combustion operation is continued until the pump signal to the electromagnetic pump 23 switches off. When the pump signal is turned off, the drive signal to the combustion blower 24 is stopped. Therefore, when the fire extinguishing command is issued by operating the operation switch 14, the electromagnetic pump 23 always outputs the tip of the plunger (and thus the nozzle). At the end of the fuel) (that is, a state in which inertia in the direction of pulling in from the tip side can be expected), and the amount of fuel emitted from the nozzle at the time of fire extinguishing can be constantly maintained. In addition, oil dripping from the nozzle tip due to inertia of the electromagnetic pump is eliminated. In addition, since the fire extinguishing operation sequence is executed after the combustion amount is shifted to the fixed point, stable control independent of the combustion mode can be performed.

[0048]

As described above, according to the first aspect of the present invention, during the fire extinguishing operation, the stop instruction of the fuel supply device (for example, the electromagnetic pump) after shifting the combustion to a predetermined combustion amount. By performing the brake control of the combustion blower after a predetermined time from the (ie, OFF signal), the blown air amount can be rapidly reduced, and as a result, the fuel mixture ratio at the time of extinguishing the fire to an appropriate value that facilitates combustion is reduced. By doing so, it is possible to create a flammable state, and it is possible to suppress unburned mixed gas (that is, generation of unburned gas) and bring the mixed gas closer to the direction in which it can be burned. Moreover, since the brake control is performed after the combustion amount is shifted to the fixed point, the start timing and the brake time of the brake control can always be uniquely set without being influenced by the combustion state at the time of fire extinguishing. The control mode is simplified, and stable control can be realized.

According to the present invention described in claim 2,
By rapidly reducing the speed of the combustion blower, the amount of combustion air is reduced and the mixing ratio of fuel is increased, making the mixed gas more flammable to suppress the generation of unburned gas in the mixed gas. Since the fan is restarted without completely stopping, the cooling of the burner (specifically, the flame forming part, the vaporizer, and the nozzle tip) is suppressed (in other words, the temperature rise at the nozzle tip due to radiation and transmission by the residual heat of the burner) In this case, it is possible to quickly shift to the post-purge operation after the fire is extinguished, to improve the fire-extinguishing characteristics by quickly starting the burner cooling, and to appropriately shift to the post-purge operation. Moreover, since the fire extinguishing operation sequence is executed after the combustion amount is shifted to the fixed point, the start timing and the brake time of the brake control, the shift timing to the post-purge operation, the post-purge time, etc. Various time controls can always be uniquely set without being influenced by the combustion state at the time of fire extinguishing, so that the control form is simplified and stable control can be realized.

Further, according to the present invention, when any abnormality (ie, error) is detected in the liquid fuel combustion device, the control device immediately shifts to a fire extinguishing operation and safely operates. Since the so-called fail-safe control for ensuring the safety is performed, the inconvenience of continuing the combustion at the time of abnormality is eliminated, and the safety of the device is ensured.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an overall configuration of an oil fan heater as a liquid fuel combustion device according to an embodiment of the present invention.

FIG. 2 is a block circuit diagram of a control device mainly including control means for controlling a liquid fuel supply device, a combustion blower, and a convection blower.

FIG. 3 is a flowchart schematically showing a control operation of a control unit.

FIG. 4 is a main flowchart schematically showing a sequence of a fire extinguishing operation in FIG. 3;

FIG. 5 is a time chart showing an outline of signal processing in the fire extinguishing sequence of FIG. 4;

[Explanation of symbols]

 H Liquid fuel combustion device (oil fan heater) 10 Control device 11 Control means (microcomputer) 21 Vaporizer (vaporization heater) 23 Fuel supply device (electromagnetic pump) 24 Blower for combustion 25 Blower for convection

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Tadashi Yamaguchi 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Nobuhiro Ogura 2-5-2 Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd.

Claims (3)

[Claims] 1. A liquid fuel supplied by a fuel supply device which operates based on an ON signal and an OFF signal supplied alternately is vaporized by a vaporizer, and the vaporized gas is mixed with combustion air from a combustion blower. Then, in a liquid fuel combustion device that ignites this mixed gas with an ignition device in a flame forming unit and burns, when extinguishing operation by an operation-off switch, the combustion is shifted to a predetermined combustion amount, and then the fuel is supplied to the fuel supply device. A liquid fuel combustion device, comprising: a control device that outputs a deceleration signal for decelerating the combustion blower for a predetermined time after a predetermined time from the supply of the OFF signal. 2. A liquid fuel supplied by a fuel supply device operating based on an ON signal and an OFF signal supplied alternately is vaporized by a vaporizer, and the vaporized gas is mixed with combustion air from a combustion blower. Then, in a liquid fuel combustion device that ignites this mixed gas with an ignition device in a flame forming unit and burns, when extinguishing operation by an operation-off switch, the combustion is shifted to a predetermined combustion amount, and then the fuel is supplied to the fuel supply device. Liquid provided with a control device that outputs a deceleration signal for controlling deceleration of the combustion blower after a predetermined time from the supply of the OFF signal, and outputs a drive signal for the combustion blower before the combustion blower does not stop. Fuel combustion device. 3. The control device according to claim 1, wherein when the control device detects that any abnormality has occurred in the liquid fuel combustion device, the control device immediately shifts to a fire extinguishing operation. Liquid fuel combustion device.