JP2515850B2 - Automatic ventilation - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an automatic ventilation device, and in particular, to the hot air generated during cooking by automatically driving a ventilation fan upon determining the start of cooking,
The present invention relates to a control system of an automatic ventilation device that detects polluted air such as smoke, odor, and gas, and automatically controls the ventilation volume (air volume) of a ventilation fan based on the detected value.

[Prior Art] As a conventional automatic ventilation device, there is a device which detects a flame depending on the presence or absence of ultraviolet rays and drives a ventilation fan for a certain period of time, as described in Japanese Utility Model Publication No. 62-95216. Also, JP-A-56-1423
As described in Japanese Patent Publication No. 33, there is an apparatus that stores a sensor output signal for a long time and compares it with a new output signal to detect a change in the sensor output signal to drive a ventilation fan. Further, as described in Japanese Utility Model Application Laid-Open No. 62-67134, there is a device that compares an output signal of a temperature sensor and an output signal of a gas sensor and drives a ventilation fan with a larger control amount (high-speed rotation side).

A technique for storing the output signal of the sensor for a long time, comparing it with a new output signal, and automatically controlling the output signal of the sensor based on the change in the output signal of the sensor is disclosed in JP-A-54-2526 and 52-59347. It is described in the official gazette.

[Problems to be Solved by the Invention]

The above-mentioned conventional technology is applied to an ignition accident (fire) caused by extinguishing a flame caused by spilling of cooked food or overheating of cooked food, which is caused while using a cooking utensil (heating device) such as a gas stove. However, there are functional issues that are not taken into consideration so that they can be dealt with immediately.

The object of the present invention is to start the operation almost at the same time as the start of cooking, detect and discharge hot air, smoke, odor, contaminated air such as gas generated during cooking, and to eliminate abnormal situations such as extinction of flames and fires. An object of the present invention is to provide an automatic ventilation device that can switch the ventilation amount to deal with it immediately. Another object of the present invention is to provide an automatic ventilation device that displays an alarm when an abnormal situation occurs.

[Means for solving the problem]

The above-mentioned object is an automatic ventilation device, an ultraviolet sensor for detecting ultraviolet rays emitted from a flame, a gas sensor for detecting contaminated air, a temperature sensor for detecting hot air, and a fan capable of discharging contaminated air, This is achieved by providing a control circuit that processes the output signal of each sensor to drive the fan, and the control circuit drives the fan as follows.

(A) When the amount of ultraviolet rays detected by the ultraviolet ray sensor reaches or exceeds a first predetermined value, the fan is driven.

(B) While the fan is being driven in (a), the amount of ultraviolet rays detected by the ultraviolet ray sensor is lower than the first predetermined value, and the amount of contaminated air detected by the gas sensor is not less than a predetermined value. Then, the rotation speed of the fan is maximized.

(C) While the fan is being driven in (a), the ultraviolet ray amount detected by the ultraviolet ray sensor is equal to or larger than a second predetermined value set to a value larger than the first predetermined value, and the temperature sensor is used. The fan is stopped when the temperature detected in step 3 reaches a predetermined value or higher.

[Action]

The ultraviolet sensor detects ultraviolet rays radiated from the flame of a cooking utensil such as a gas stove and outputs an ultraviolet ray detection signal corresponding to the intensity level of the ultraviolet rays to a control circuit. The gas sensor detects contaminated air and outputs a gas detection signal corresponding to the concentration level to the control circuit. The temperature sensor detects the temperature of hot air and outputs a temperature detection signal corresponding to the temperature level to the control circuit.

The control circuit determines that the cooking utensil such as the gas stove is ignited and drives the fan when the amount of the ultraviolet rays detected by the ultraviolet ray sensor becomes equal to or more than the first predetermined value. At this time, it is preferable to control the rotation speed of the fan based on the amount of contaminated air detected by the gas sensor or the temperature detected by the temperature sensor.

Further, when the amount of ultraviolet rays detected by the ultraviolet ray sensor is equal to or more than a first predetermined value and the fan is driven, the amount of ultraviolet rays detected by the ultraviolet ray sensor is lower than the first predetermined value, When the amount of contaminated air detected by the gas sensor exceeds a predetermined value, it is determined that the flame has disappeared due to spillage of cooked food, and the fan speed is maximized.

Further, when the amount of ultraviolet rays detected by the ultraviolet sensor becomes equal to or larger than the first predetermined value and the fan is driven, the amount of ultraviolet rays detected by the ultraviolet sensor is set to a value larger than the first predetermined value. When the temperature exceeds the second predetermined value and the temperature detected by the temperature sensor exceeds the predetermined value, it is determined that an ignition accident due to overheating of the cooked product has occurred and the fan is stopped.

As a result, the fan starts operating almost at the same time as the start of cooking, operates according to the level of hot air or contaminated air, and switches the ventilation rate in response to an abnormal situation as soon as possible. Sometimes it is possible to perform a suitable operation.

Further, the control circuit sends a signal to the alarm device when an abnormal situation occurs, so that the alarm device displays an alarm. Thereby, the user can prevent the accident from spreading.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is an example of a structural view of the automatic ventilation device of the present invention. FIG. 2 (a) is a front view in which the front cover 29 of the main body 20 of the automatic ventilation device is removed, and a part is cut away. FIG. 2 (b) shows the main body 20 of the automatic ventilation device.
It is the side view which notched a part of. The illustrated automatic ventilation device is installed in the upper part of the cooking place and near the ceiling.

In FIG. 2, 1 is a gas sensor for detecting polluted air (hereinafter, referred to as contaminated air), 2 is a temperature sensor for detecting hot air, and 3 is a UV sensor for detecting ultraviolet rays emitted from a flame of a gas stove (not shown). An ultraviolet ray detecting tube (ultraviolet ray sensor); 24, a fan for discharging contaminated air; and 25, a fan motor for driving the fan 24. Hereinafter, the fan 24 and the fan motor 25 are collectively called a ventilation fan.

Further, 26 is a grease filter that captures and removes particle components such as oil mist from contaminated air, 27 is a control circuit that controls the ventilation operation of the ventilation fans (24, 25), and 28 and 28 are lamps that illuminate the lower part of the main body 20. It is a lamp house that houses (not shown). 29 is a front cover provided to improve the efficiency of capturing contaminated air, 30 is a curtain plate that guides the contaminated air remaining on the ceiling surface (not shown) to the ventilation fans (24, 25), 31 is sucked by the fan 24 It is an exhaust port for discharging the contaminated air to the outside.

When a gas stove installed below the main body 20 ignites and a flame is generated, the ultraviolet ray detection tube 3 detects the ultraviolet ray radiated from the flame, and a signal indicating the presence or absence thereof (and an intensity level signal) is a control circuit. Supply to 27. The control circuit 27 receives the signal from the ultraviolet ray detecting tube 3 and drives the ventilation fans (24, 25).

As a result, contaminated air such as hot air and smoke generated by the flame of the gas stove is discharged to the main body of the automatic ventilation system installed above.
Guided to 20 . And mainly, the contaminated air is
Collected by the fan through the grease filter 26
Inhaled to 24. At this time, a part of the contaminated air whose particle components have been captured and removed by the grease filter 26 is sucked into the fan 24 after passing through a place where the gas sensor (reducing gas sensor) 1 and the temperature sensor 2 are installed.

The temperature sensor 2 detects the temperature of the contaminated air and supplies a signal of the temperature level to the control circuit 27. Similarly, the gas sensor 1 detects smoke, odor, gas, etc. in the contaminated air,
A signal corresponding to the level is supplied to the control circuit 27. The control circuit 27 detects contaminated air from the signals supplied from the temperature sensor 2 and the gas sensor 1 and continuously drives the ventilation fan (24, 25). The contaminated air sucked by the fan 24 is discharged to the outside through the exhaust port 31.

As shown, the gas sensor 1 and the temperature sensor 2 are installed behind the grease filter 26 so as to maintain the detection performance over a long period of time and maintain reliability. The UV detector tube 3 is also a grease filter for the same reason.
It is installed in the rear of 26 and is housed in a case 21 having a sealed structure except for the surface facing the gas stove. Also,
Although an alarm device (abnormality notification device) is provided on the main body 20 , the illustration and description thereof are omitted in FIG.

Next, the configuration of the control system in the automatic ventilation device of the present invention will be described with reference to the block diagram of FIG.

In FIG. 1, 1-3 are the sensors shown in FIG. 2, respectively, and in particular, 3 is an ultraviolet ray detection tube having a pulse generator (not shown) incorporated therein, which indicates the intensity of the incident ultraviolet ray in a unit time. The number of pulses is replaced and output. Reference numeral 7 is a microcomputer (hereinafter abbreviated as a microcomputer), and 4 is a pulse counter that counts the pulses output from the ultraviolet detection tube 3 after being reset by the microcomputer 7 and supplies the count value to the microcomputer 7.

Reference numeral 5 denotes a multiplexer (analog switch) that switches and outputs the output of the gas sensor 1 and the output of the temperature sensor 2 according to a switching signal from the microcomputer 7. 6
Converts the output of the multiplexer 5 into a digital signal,
The A / D converter supplies this digital signal to the microcomputer 7. 8 is a RAM (random access memory) in which data is recorded by the microcomputer 7 and can be read.
Is. Reference numeral 9 denotes a ROM (read only memory) from which constant data stored in advance is read by the microcomputer 7.

Further, 10 is a motor control circuit for controlling the rotation speed of the fan motor 25 in accordance with the output signal of the microcomputer 7. The fan 24 in FIG. 2 changes the ventilation amount by changing the rotation speed of the fan motor 25. 12 is an alarm device including a lamp and a buzzer. The control circuit 27 described with reference to FIG.
Is a microcomputer 7, a pulse counter 4, a multiplexer 5, an A / D converter 6, a RAM 8, a ROM 9 and a motor control circuit 10.
It is composed of

Next, the operation of the control system of this embodiment shown in FIGS. 1 and 2 will be described with reference to the flow charts of FIGS.

3 and 4 are diagrams showing the algorithm of the microcomputer 7. Now, it is assumed that the user connects the automatic ventilation device of the present invention to a power supply. The microcomputer 7 starts operating at the same time when the power is turned on. STAR at this point in Fig. 3
Shown as T40. After that, the microcomputer 7 resets the pulse counter 4 to prepare for ultraviolet ray detection (step 4).
1).

Then, the microcomputer 7 controls the multiplexer 5 to
The output signal of the gas sensor 1 and the output signal of the temperature sensor 2 are read via the A / D converter 6 respectively (step 4
2). The microcomputer 7 stores the read output signal of the gas sensor 1 in the RAM 8 as a gas sensor output (concentration) reference value SENφ. Similarly, the output signal of the temperature sensor 2 is stored in the RAM 8 as the temperature reference value THφ (step 43).

After that, the output signal of the gas sensor 1 and the output signal of the temperature sensor 2 are read again in the same manner as in step 41 described above. The weekly force signal of the gas sensor 1 at this time is stored in the RAM 8 as the gas sensor output value SEN1. The output signal of the temperature sensor 2 is stored in the RAM 8 as the temperature measurement value TH1 (step 44).

Then, the microcomputer 7 calculates the output ratio SC of the gas sensor output reference value SENφ and the gas sensor output value SEN1 by SEN1 / SENφ. This ratio SC is also stored in the RAM 8. In addition, the temperature difference TC between the temperature measurement value TH1 and the temperature reference value THφ is calculated as TH1-THφ
It is calculated by: The microcomputer 7 stores this temperature difference TC in the RAM 8 (step 45).

Next, it is determined whether the predetermined time TM3 has elapsed (step 46). Here, the time TM3 indicates a cycle of the timing of detecting the ultraviolet rays. When this time TM3 has elapsed, the microcomputer 7 resets the pulse counter 4 as shown in step 47.

Next, the output of the pulse counter 4 is read, and the read ultraviolet ray measurement value PC is stored in the RAM 8 (step 48).
Here, when the ultraviolet ray measurement value PC is equal to or larger than a predetermined set value N, the ultraviolet ray detection tube 3 detects the ultraviolet ray radiated from the flame of the gas stove, and outputs a pulse output based on the detection result to the pulse counter 4. Indicates that it was output.

Note that the microcomputer 7 regards the time when the gas stove is ignited (ignited) as the start time of cooking, and proceeds with the process. If the ultraviolet ray measurement value PC is less than the set value N, the microcomputer 7 determines that the gas stove is in an unused state (step 55 in FIG. 4).

When the gas stove is not used, whether the ventilation fan is stopped, that is, the microcomputer 7
It is determined whether the motor is in the stopped state via the motor control circuit 10 of 25 (step 56 in FIG. 4). When the ventilation fan is stopped, the process proceeds to step 57, and when the ventilation fan is driven, the process proceeds to step 58.

In step 57, the presence or absence of hot air, smoke, odor, gas, etc. generated by cooking is determined. Specifically, the steps
The output ratio SC calculated in 45 is compared with the output ratio reference value SCD stored in the ROM 9 in advance. In addition, the temperature difference TC and ROM9
The temperature difference reference value THD1 stored in is compared. here,
If SC <SCD and TC ≦ THD1, it is determined that hot air, smoke, odor, gas, etc. are not generated, and the process proceeds to step 59 (update of the reference value).

On the other hand, when the conditions of SC <SCD and TC ≦ THD1 are not satisfied, it is determined that hot air, smoke, odor, gas, etc. are generated by cooking, and the process proceeds to the determination process of step 58. In step 58, the output ratio SC and the output ratio reference value SCD are compared. Further, the temperature difference TC stored in advance in the ROM 9 is compared with the temperature difference reference value THD2.

As a result of the comparison, if SC ≧ SCD or TC ≧ THD2,
The microcomputer 7 drives the ventilation fan (step 60). If the comparison result does not satisfy the above condition, the ventilation fan is driven for a predetermined (specified) time only (step 61). Step 59 ~
After completing one of the processes shown in step 61, that is, the process of updating the reference value, driving the ventilation fan, or driving the ventilation fan for the designated time, the process returns to step 44 in FIG. Repeat the process.

Next, the updating of the reference value in step 59 of FIG. 4 will be described with reference to the flowchart of FIG.

The updating of the reference value (step 59) is a process for preventing malfunction due to environmental changes other than cooking. The update processing cycle is a predetermined time, as shown in step 62.
Determined by TM1. When the time TM1 elapses, the microcomputer 7
The gas sensor output value SEN1 stored in 1 is reset as the gas sensor output reference value SENφ, and a new SENφ is stored in the RAM8.

Similarly, the microcomputer 7 stores the measured temperature value TH1 in the RAM 8 as a new temperature reference value THφ (step 63). In this way, in the updating of the reference value (step 59 in FIG. 4), the gas sensor output reference value SENφ and the temperature reference value THφ are updated. In this way, the reference value SEN for controlling
Updating φ and THφ has an advantage in that a long-period input signal detected by each sensor (1, 2) can be removed.

Next, driving of the ventilation fan in step 60 of FIG. 4 will be described with reference to the flowchart of FIG.

First, a value for determining the ventilation volume (air volume), that is, the control volume FS1 of the ventilation fan is calculated according to the output ratio SC based on the gas sensor output reference value SENφ (step 64). Further, the control amount FC2 of the ventilation fan is similarly calculated according to the temperature difference TC (step 65). These control variables FS1, FS2
Is calculated based on the specifications of the fan 24 and the fan motor 25 and the control function of the motor control circuit 10 by a preset design equation or empirical equation.

The microcomputer 7 compares the control amount FS1 calculated in this way with the control amount FS2 (step 66). Then, the motor control circuit 10 is operated using the control amount having the larger value (step 67 or step 68). According to such a driving method, there is a merit that an optimal ventilation amount can be assigned to each of the temperature and the gas component (concentration) of the contaminated air.

Next, the specified time drive of the ventilation fan in step 61 of FIG. 4 will be described using the flowchart of FIG.

The driving of the ventilation fan for the designated time is a process for sufficiently discharging the remaining contaminated air when the degree of contamination of the contaminated air is reduced by the driving of the ventilation fan from the start of driving. Specifically, when the ventilation fan is driven, the drive is forcibly continued for a predetermined time TM2.

In FIG. 7, the processing from step 70 to step 74 is the same as the ventilation fan driving processing (from step 64 to step 68) in FIG. When the predetermined time TM2 has elapsed, the microcomputer 7 uses the motor control circuit 10 to stop the ventilation fan (step 75). Then, in the same manner as step 63 in FIG. 5, the gas sensor output reference value SENφ and the temperature reference value T
Update Hφ (step 76).

A characteristic diagram when the automatic ventilation device of this embodiment is actually driven is shown in FIGS. 8 to 11 and will be described in detail.

FIG. 8 is a characteristic diagram showing an operation when grilled fish is cooked using a gas stove. The horizontal axis represents time t, and the vertical axis represents the gas sensor output value SEN1 and the measured temperature value TH1.
Indicates. In Fig. 8, the solid line indicates the gas sensor output value SEN1.
, And the dashed line indicates the measured temperature value TH1. In the drawing, the setting positions of the output ratio reference value SCD and the temperature difference reference values THD1 and THD2 are indicated by a two-dot chain line.

Time point t ₁₀ indicates a time point when the reference value is updated (step 59 in FIG. 4). At this time t ₁₀ , the count value PC of the pulse counter 4 for counting the output of the ultraviolet ray detection tube 3 is 0 because the gas stove is not ignited again. The ignition of the gas stove is made at time t _11, UV detection pipe 3 supplies detect the ultraviolet rays emitted from the gas stove flames, a pulse corresponding to the pulse counter 4 to the radiation intensity of the ultraviolet.

The pulse counter 4 counts the output of the ultraviolet detection tube 3. Since this count value PC satisfies the condition (PC ≧ N) shown in step 55 of FIG. 4, the microcomputer 7 executes step 58.
Is performed. At time t ₁₁ in FIG. 8, the output changes of the gas sensor 1 and the temperature sensor 2 are still small, and SC ≧ SC.
Since the condition of D or TC ≧ THD2 is not satisfied, the ventilation fan is driven for the specified time described in step 61 of FIG. Here, the time from ignition of the gas stove to driving of the ventilation fan is extremely short.

Thereafter, the gas sensor output value SEN1 increases due to leakage of raw gas at the time of ignition of the gas stove. Eventually, time t
_When it becomes ₁₂ , the condition of step 58 in FIG. 4, that is, SC ≧ SCD is satisfied. As a result, the microcomputer 7 drives the ventilation fan described in step 60 of FIG. During the use of the gas stove, the count value PC keeps a relationship of PC ≧ N.

On the other hand, the gas sensor 1 detects gas components such as smoke, odor, and gas generated by burning fish. Therefore, the gas sensor output value SEN1 increases from time t ₁₂ to time t ₁₄ in FIG. In this case, the ventilation volume (air volume) of the ventilation fan is automatically controlled according to the value of the output ratio SC. At the same time, the temperature of ventilation generated by the gas stove rises as the cooking time elapses. The temperature sensor 2 detects the temperature of the hot air.

Therefore temperature measurements TH1 as shown at time t ₁₃ from the time point t ₁₂ of Figure 8 is increased. Becomes a time t _13, the conditions of FIG. 4 step 58, namely satisfying TC ≧ THD2. As a result,
As shown in FIG. 6, the microcomputer 7 controls the ventilation volume (air volume) of the ventilation fan using the larger control volume of the control volume FS1 and the control volume FS2.

Cooking is completed and the stove fire extinguishing is carried out at time t _14, the count value PC of the pulse counter 4 becomes zero.
Also, the gas sensor output value SEN1 and the temperature measurement value TH1 begin to fall. Output ratio SC based on gas sensor output value SEN1
Does not satisfy the condition (SC ≧ SCD) of step 58 in FIG. 4 at time t ₁₅ . However, since the temperature difference TC still satisfies the condition of step 58 (TC ≧ THD2), the time t
Up to ₁₆ , the ventilation fan is driven according to the temperature difference TC (step 60 in FIG. 4).

After the time point t ₁₆ , the condition of step 58 in FIG. 4 is not satisfied, but the ventilation fan is driven for the designated time in step 61 of FIG. By driving this ventilation fan for a specified time,
Remaining hot air and contaminated air are discharged. After that, the specified time TM2 (for example, several minutes to several tens of minutes) has elapsed and time t
_When it reaches ₁₇ , the microcomputer 7 stops the ventilation fan and updates the reference value (steps 75 and 76 in FIG. 7).

At the time t ₁₇ or later, the count value PC of the pulse counter 4
Is 0, and the ventilation fan is stopped. Microcomputer 7
Performs the judgment process of step 57 in FIG. 4, and the condition SC <SCD
And TC ≤ THD1 are satisfied, then step 59
The reference value of is updated. This updating of the reference value is performed with the time TM1 as one cycle, as shown in step 62 of FIG.

Next, the operation when boiling water with a gas stove will be described with reference to the characteristic diagram of FIG. The description method of FIG. 9 is the same as that of FIG.

In FIG. 9, time t ₂₀ indicates the time when the reference value was updated (step 59 in FIG. 4). After that, when the gas stove is ignited at time t ₂₁ , the ultraviolet ray detection tube 3 detects the ultraviolet rays emitted from the flame of the gas stove and supplies a pulse to the pulse counter 4. The count value PC of the pulse counter 4 is the condition (PC ≧ PC ≧ 55 shown in step 55 of FIG.
N) is satisfied, the discrimination processing of step 58 in the microcomputer 7 is performed.

In Figure 9 the time t _21, in order not to satisfy the condition of the SC ≧ SCD or TC ≧ THD2, performs specified time driving the ventilating fan in Figure 4 step 61. The driving of the fan motor 11 of the ventilation fan is started almost at the same time as the ignition of the gas stove. Thereafter, the gas sensor output value SEN1 increases due to leakage of raw gas at the time of ignition of the gas stove.

Eventually, at time t ₁₂ , the condition of step 58 in FIG. 4,
That is, SC ≧ SCD is satisfied. As a result, the microcomputer 7 drives the ventilation fan described in step 60 of FIG. In the case of boiling water, normally, smoke, odor, gas, etc. are not generated, and the gas sensor output value SEN1 decreases. Then, at time t ₂₃ , the condition of step 58 (SC ≧ SCD) is not satisfied.

Therefore, the microcomputer 7 switches the operation from driving the ventilation fan in step 60 to driving the ventilation fan for the designated time in step 61. On the other hand, the temperature of the hot air generated by the gas stove increases. This temperature rise includes the temperature rise of the surrounding air. Then, before the designated time TM2 elapses, the condition of step 58, that is, TC ≧ THD2 is satisfied,
At time t ₂₄ , the ventilation fan in step 60 is driven again.

When the hot water is boiled and the gas stove is extinguished at time t ₂₅ , the count value PC of the pulse counter 4 becomes 0 and the temperature measurement value TH1 begins to decrease. As a result, the condition (TC ≧ THD2) of step 58 in FIG. 4 is not satisfied at time t ₂₆ . Then, the microcomputer 7 switches the operation from the driving of the ventilation fan in step 60 to the driving in step 61 again. Thereafter, at a time point t ₂₇ specified time TM2 has elapsed, the microcomputer 7 stops the ventilation fan, and updates the reference value (FIG. 7 step 75, 76).

After time t ₂₇ , the count value PC is 0,
Ventilation fan is off. The microcomputer 7 is step 57 in FIG.
To step 59, the reference value is updated.
As a result, automatic ventilating device of this embodiment is the same state as the state at time t _20.

Next, the operation when the flame of the gas stove disappears during cooking due to boiling, spilling, or blowing of wind will be described with reference to the characteristic diagram of FIG. In addition,
The description method of FIG. 10 is the same as that of FIG. 9, and similarly, it is a diagram showing an operation in the case of boiling water with a gas stove, and is a characteristic diagram when the extinguishing of the gas flame occurs on the way.

In FIG. 10, time point t ₃₀ indicates the time point when the reference value was updated. After that, when the gas stove is ignited at time t ₃₁ , the ultraviolet detection tube 3 detects the generation of ultraviolet rays due to the ignition, and the microcomputer 7 drives the ventilation fan via the motor control circuit 10. Further, the gas sensor output value SEN1 rises due to the leakage of raw gas when the gas stove is ignited.

Becomes a time t _32, the microcomputer 7 is a gas sensor output value SEN
According to 1, the ventilation fan is driven (step 60 in FIG. 4). From time t ₃₃ to time ₃₄ , the microcomputer 7 drives the ventilation fan for the designated time in step 61 of FIG. The above operation is the same as the operation shown in FIG.

Eventually, the hot water is gradually boiled increased temperature of hot air, driven ventilators again Figure 4 step 60 at time t ₃₄ is performed. Then, hot water at the time t ₃₅ is violently boiling and cow,
Hot water flows out occurs extinction of the gas stove flame at the time t _36. Simultaneously with the extinction of the flame, the count value PC of the pulse counter 4 becomes 0, and the temperature measurement value TH1 begins to decrease.

On the other hand, the gas sensor output value SEN1 greatly increases in a short time due to generation of a large amount of raw gas. As a result, in step 49 of FIG. 3, PC <N and SC ≧ SCD
Is satisfied, and the microcomputer 7 determines that an abnormal situation (going out) has occurred. Then, the microcomputer 7 operates the motor control circuit 10 by using the maximum control amount (step 50 in FIG. 3).

Therefore, the generated raw gas is rapidly discharged. Further, the microcomputer 7 sends a signal to the alarm device 12 (abnormality notification device) to cause the lamp to blink and the buzzer to generate an alarm (step 51 in FIG. 3).

Next, the operation when the cooked food (tempura oil) is ignited due to overheating or the like will be described with reference to the characteristic diagram of FIG.

Also in FIG. 11, as in the case of FIG. 10, time t ₄₀
Indicates the time when the reference value was updated. After that, when the gas stove is ignited at time t ₄₁ , the ultraviolet ray detection tube 3 detects the generation of ultraviolet rays due to the ignition, and the microcomputer 7 drives the ventilation fan via the motor control circuit 10. Further, the gas sensor output value SEN1 rises due to the leakage of raw gas when the gas stove is ignited.

Becomes a time t _42, the microcomputer 7 is a gas sensor output value SEN
According to 1, the ventilation fan is driven (step 60 in FIG. 4). From time t ₄₃ to time t ₄₄ , the microcomputer 7 drives the ventilation fan for the designated time in step 61 in FIG. The above operation is the same as the operation in FIG.

Eventually, the temperature of the cooking oil is up, the temperature of the hot air also increases, driving the ventilation fan again FIG. 4 step 60 at time t ₄₄ is performed. Further excessive heating was performed,
At t ₄₅ , the temperature of the tempura oil becomes abnormally high and the smell of the tempura oil increases. The cooking oil is ignited at last time t _46, fire. Simultaneously with the occurrence of the fire, the count value PC of the pulse counter 4 rapidly increases and becomes equal to or more than a second set value N 'which is much larger than the set value N.

A little later than this, the temperature measurement value TH1 also sharply increases, and the temperature difference TC becomes equal to or higher than the third temperature difference reference value THD2 'which is much larger than the temperature difference reference value THD2. The set value N 'and the temperature difference reference value THD2' are values stored in the ROM 9 in advance.

As a result, in step 52 of FIG. 3, PC ≧ N ′, TC
The condition of ≧ THD2 ′ is satisfied, and the microcomputer 7 determines that an abnormal situation (fire occurrence) has occurred. Then, the microcomputer 7 stops driving the ventilation fan (step 5 in FIG. 3).
3). For this reason, ventilation is stopped and the progress of the fire is slowed (weakened). Further, the microcomputer 7 is provided with an alarm device 12
A signal is sent to the (abnormality notification device) to cause a lamp to blink and a buzzer to generate an alarm (step 54 in FIG. 3).

The automatic ventilation device according to the present invention is provided with a microcomputer 7.
Alternatively, it is also possible to incorporate an abnormality notification unit connected to the alarm device 12 and control an external device (for example, a telephone) via this unit to make a notification using the external device when the flame goes out or a fire occurs. .

Even if control is performed using the change value of the output of the ultraviolet sensor, stable operation can be performed.

〔The invention's effect〕

According to the present invention, the drive of the ventilation fan can be started almost at the same time as the start of cooking, and the ventilation fan can be automatically controlled by detecting hot air or contaminated air, and further according to the environmental conditions of the place where it is used. Since the standard is set automatically, usability can be improved, malfunctions are less likely to occur, and abnormal situations such as flame extinguishing during cooking and ignition (fire) can be immediately and automatically dealt with, and an alarm can be issued. An automatic ventilation device can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing a control system of an automatic ventilation device according to an embodiment of the present invention, FIG. 2 is a diagram showing a structure of an automatic ventilation device according to an embodiment of the present invention, and FIGS. 8 is a diagram showing a flowchart of the microcomputer 7 shown in FIG. 1, 8
FIG. 11 to FIG. 11 are characteristic diagrams when the automatic ventilation device of the present invention is driven. 1 ... Gas (reducing gas) sensor, 2 ... Temperature sensor,
3 ... UV sensor (UV detection tube), 4 ... Pulse counter, 5 ... Multiplexer, 6 ... A / D converter, 7
... Microcomputer, 8 ... RAM, 9 ... ROM, 10
...... Motor control circuit, 11 ...... Fan motor, 12 …… Alarm device (error notification device).

Claims (2)

(57) [Claims] 1. An ultraviolet sensor for detecting ultraviolet rays emitted from a flame, a gas sensor for detecting contaminated air, a temperature sensor for detecting steam, a fan capable of discharging contaminated air, and each of the sensors. An automatic ventilator comprising a control circuit for processing an output signal to drive the fan, the control circuit driving the fan as follows. (A) When the amount of ultraviolet rays detected by the ultraviolet ray sensor reaches or exceeds a first predetermined value, the fan is driven. (B) While the fan is being driven in (a), the amount of ultraviolet rays detected by the ultraviolet ray sensor is lower than the first predetermined value, and the amount of contaminated air detected by the gas sensor is not less than a predetermined value. Then, the rotation speed of the fan is maximized. (C) While the fan is being driven in (a), the ultraviolet ray amount detected by the ultraviolet ray sensor is equal to or larger than a second predetermined value set to a value larger than the first predetermined value, and the temperature sensor is used. The fan is stopped when the temperature detected in step 3 reaches a predetermined value or higher. 2. The automatic ventilation device according to claim 1, further comprising an alarm device that displays an alarm in the case of (b) and / or (c).