JPH0116967Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a portable kerosene stove, and particularly relates to an improvement in a means for detecting an oxygen deficiency state.

[Conventional technology]

Portable kerosene heaters have the advantage of being easily portable and can be used in any room, but on the other hand, because they emit indoor air, if used for a long time, the room becomes deficient in oxygen, which has a negative impact on the human body.

Conventionally, the combustion flame in the combustion section is detected, the detected value is stored, and this stored value is compared with the detected value after a certain period of time (for example, after 60 seconds).If the difference between the comparison values exceeds a predetermined value, A stove has been proposed that detects a lack of oxygen and extinguishes the fire. {Jitsugan 1974-
No. 052259 (Utility Model Publication No. 55-153462)} [Problem to be solved by the invention] However, in the conventional stove as described above, if the combustion flame detection value decreases by more than a predetermined difference over a certain period of time, Since the sensor only detects an oxygen-deficient state, if the combustion flame detection timing is short, the value of the predetermined difference must be made small, which is likely to cause malfunction. Therefore, the detection timing requires about 60 seconds, so if the detection is activated when the combustion flame drops to a level within a predetermined difference due to oxygen deficiency, the extinguishing operation will not occur until approximately 60 seconds have passed. There was a risk of an oxygen deficiency accident.

Therefore, the present invention provides a portable kerosene stove that can reliably detect in real time when the wick becomes deficient in oxygen after normal and stable combustion, and perform the necessary actions such as extinguishing the fire and notifying the user, thereby further improving safety. This is what I am trying to do.

[Means and actions to solve the problem]

This device uses a temperature detection element to continuously detect the temperature near the wick, and a timer disables oxygen deficiency detection for a certain period of time from the start of combustion until the wick reaches normal and stable combustion. When the detection element output level falls below the voltage level corresponding to the preset oxygen deficiency judgment temperature, the fire extinguishing system is activated.
It is designed to operate a response device such as a notification device. In other words, the temperature near the lamp wick, for example, the wick guide cap that supports the lamp wick, rises with the start of combustion at time t ₀ , as shown in Figure 1, and after a certain period of time, at time t ₁ , the temperature shifts to normal and stable combustion.
The temperature will be maintained at around 200℃. Then time t ₂
When there is a lack of oxygen, incomplete combustion occurs, causing the flame to separate from the wick and reducing the lamp's power. Therefore, for a certain period of time from the start of combustion until the wick reaches normal and stable combustion, a timer disables the oxygen deficiency detection operation to prevent malfunctions due to temperature detection below the oxygen deficiency determination temperature, and after transitioning to normal and stable combustion, the wick guide is disabled. By detecting that the temperature of the cap has decreased to, for example, T ₀ ° C. or lower, it is possible to reliably detect an oxygen deficiency state in real time.

This idea was made based on this principle.

[Example of idea]

Figure 2 shows the external appearance. 1 is the housing, 2 is an oil tank housed in one side of the housing 1, and 3 is an arc-shaped reflective plate 4 located at the upper center of the housing 1.
It is a combustion chamber with an open front. Reference numeral 5 denotes a combustion mechanism provided extending from the central lower part of the combustion chamber 3 to the lower part of the housing 1, and is composed of a burner part 6, a fire pan 7, a lamp wick 8, a wick guide cap 9, and a combustion tube 10 having a hollow part. has been done. A negative characteristic thermistor 11 is provided at the center of the core guide cap 9 as a temperature detection element. A knob 12 is provided at the bottom of the housing 1 to raise the lamp wick 8 to the combustion position.

FIG. 3 shows the circuit configuration, in which a solenoid 15 for core fall prevention is connected to the power plug 13 via a normally open contact 14 of a relay to be described later, and the primary winding of a power transformer 17 is connected via a start switch 16. Connected. The input terminal of a full-wave rectifier diode bridge 18 is connected to the secondary winding of the power transformer 17. The diode bridge 18
A smoothing capacitor 19 is connected between the output terminals of the . A timer circuit 21, the thermistor 11 and a resistor 22 are connected between both ends of the smoothing capacitor 19 via the collector and emitter of an NPN transistor 20.
A series circuit of resistors 23 and 24, and a comparator 25 are connected in parallel. A resistor 26 is connected between the collector and base of the transistor 20.
A Zener diode 27 is connected between the base of the transistor 20 and the negative terminal of the smoothing capacitor 19. The connection point P ₁ between the thermistor 11 and the resistor 22 is connected to the inverting input terminal (-) of the comparator 25, and the connection point P ₂ between the resistors 23 and 24 is connected to the non-inverting input terminal (-) of the comparator 25. +) is connected. The output terminal of the timer circuit 21 is connected to the connection point _P2 . A relay 28 for driving the normally open contact 14 is connected between the positive end of the smoothing capacitor 19 and the output terminal of the comparator 25. The solenoid 15 operates a locking mechanism that locks the lamp wick 8 in the combustion position, and together with the relay 28 constitutes a response device. The locking mechanism is a plunger 29 of the solenoid 15 as shown in FIG.
One end of an L-shaped solenoid lever 30 is locked to the lever. The solenoid lever 30 is rotatably provided around an intermediate portion thereof, and its other end is locked to the lower side of one end of a clutch lever 31. The solenoid lever 30 is constantly given a counterclockwise rotational force by a spring 32 attached to its intermediate rotating portion. The clutch lever 31
The wick rotates around its middle portion, and the other end is engaged with a ratchet gear 33 that locks the combustion wick in a predetermined raised position. The clutch lever 31 has one end locked with a support plate 34 and the other end locked with the lever 31, and a spring 35 is attached to the intermediate rotating portion thereof to urge the lever 31 counterclockwise in the figure. . The ratchet gear 33 rotates clockwise in the figure as the combustion wick rises, and is prevented from rotating counterclockwise by the clutch lever 31, thereby locking the combustion wick from falling. When the locking by 31 is released, the combustion wick is rotated counterclockwise and the combustion wick is dropped. That is, in this lock mechanism, the other end of the clutch lever 31 is normally released from the ratchet gear 33 as shown by the two-dot chain line in the figure, but when the solenoid 15 is energized, the plunger 29 is released as shown by the solid line in the figure. This causes the solenoid lever 30 to rotate clockwise against the biasing force of the spring 32, thereby rotating the clutch lever 31 counterclockwise.
This prevents the ratchet gear 33 from rotating counterclockwise. Further, the lock mechanism has a lower end portion on the support plate 34.
4 and the vibration sensor 36 passing through the clutch lever 31
is placed and when a vibration occurs, the vibration sensor 36 tilts as shown by the two-dot chain line in the figure, and the clutch lever 31 is rotated clockwise at its lower end. The wick 8 is ignited by the wick 8.
When the lamp wick 8 rises to the combustion position, this is automatically done by an igniter (not shown), and the start switch 16 is turned on as the lamp wick 8 rises.

Note that the voltage level of the connection point _P2 is determined by the temperature when the thermistor 11 is in an oxygen-deficient state, for example, the first
The connection point P ₁ when detecting T ₀ ℃ in the figure
is set to be equal to the voltage level of Further, when the timer circuit 21 starts to be energized, the output from the output terminal is held at a low level for a sufficient period of time until the lamp wick 8 reaches normal and stable combustion, and then the output is inverted to a high level. .

In the embodiment of the present invention constructed as described above, when the knob 11 is rotated to raise the lamp wick 8 to a predetermined combustion position, the start switch 16 is turned on, the timer circuit 21 starts operating, and the lamp wick 8 is turned on. Ignition is started. At this time, the resistance value of the thermistor 11 is still large, but the timer circuit 2
Since the 1 output is at a low level, the level of the input to the comparator 25 at the connection point _P1 is higher than the level at the connection point _P2 , and the output of the comparator 25 becomes a low level. Therefore, the relay 28 is activated and its normally open contact 14 is opened.
When turned ON, the solenoid 15 is energized, and the counterclockwise rotation of the ratchet gear 33 is prevented, thereby preventing the lamp wick 8 from falling. In this way, combustion of the lamp wick 8 is started, and after a certain period of time, the lamp wick 8 enters a normal and stable combustion state. Thereafter, the output of the timer circuit 21 is inverted from low level to high level. However, at this time, the resistance value of the thermistor 11 detects the temperature during normal and stable combustion and has become sufficiently small, so the connection point _P1 level remains higher than the connection point _P2 level, and the comparator 25 output is at a low level. hold. In this way, the combustion of the wick 8 is continued. If the interior of the room becomes oxygen deficient during such combustion, the lamp wick 8 will undergo incomplete combustion, causing a phenomenon in which the flame separates from the lamp wick 8, and the temperature detected by the thermistor 11 will decrease. When the temperature detected by the thermistor 11 becomes below T ₀ ℃, the connection point _P1 level becomes the connection point.
_P2 level or lower, and the output of the comparator 25 is inverted from low level to high level. That is, it outputs an oxygen deficiency detection signal. This deenergizes the relay 28 and turns off its normally open contact 14, turning the solenoid 1
5 is stopped. Then, the solenoid lever 30 rotates counterclockwise, the clutch lever 31 disengages from the ratchet gear 33, and the ratchet gear 33 rotates counterclockwise, causing the lamp wick 8 to fall and be extinguished. Furthermore, the start switch 16 is turned OFF due to the falling of the lamp wick 8.

In this way, the timer circuit 21 disables the oxygen deficiency detection operation of the comparator 25 from the start of combustion until the lamp wick 8 achieves normal and stable combustion.
Malfunctions due to temperature detection below T ₀ °C are prevented. After the lamp wick 8 has undergone normal and stable combustion, when an oxygen deficiency condition is detected based on the continuous detection output of the temperature near the lamp wick by the thermistor 11, an extinguishing operation is immediately performed. Therefore, by appropriately setting the oxygen deficiency determination temperature T ₀ °C, it is possible to reliably prevent accidents due to oxygen deficiency after normal and stable combustion, and improve safety.

In addition, in the above embodiment, a relay,
Although the fire extinguishing system has been described using a fire extinguishing system consisting of a solenoid, the present invention is not necessarily limited to this. For example, a system using a notification device such as a buzzer or a lamp may be used. Further, in the above embodiment, the thermistor is provided on the core guide cap, but the present invention is not limited to this, and the thermistor may be provided in the hollow part of the combustion tube 10. Further, in the embodiment described above, a negative characteristic thermistor is used as the temperature detecting element, but it is needless to say that the present invention is not limited to this.

[Effect of idea]

As described above, according to this invention, when the lamp wick becomes deficient in oxygen after normal and stable combustion, it is possible to detect this in real time and take necessary actions such as extinguishing the fire or giving an alarm. It is possible to provide a portable kerosene stove that can prevent malfunctions due to temperature detection below the oxygen deficiency determination temperature and further improve safety.

[Brief explanation of drawings]

Figure 1 shows the time and
A graph showing the temperature characteristics of the wick guide cap, Fig. 2 is an external view showing an embodiment of the present invention, Fig. 3 is a circuit diagram of the same embodiment, and Fig. 4 is a diagram showing the locking mechanism of the wick in the same embodiment. be. 2...oil tank, 8...lamp wick, 9...wick guide cap, 11...negative characteristic thermistor, 14...
... Normally open contact of relay, 15 ... Solenoid, 21
...Timer circuit, 22, 23, 24...Resistor, 2
5... Comparator, 28... Relay.

Claims (1)

[Scope of utility model registration request] In a portable oil stove, an oil tank is provided and a lamp wick impregnated with oil supplied from the oil tank is provided so as to be movable up and down, and the temperature in the vicinity of the lamp wick is continuously controlled by raising the lamp to perform a combustion operation. Comparison that compares the temperature detection element to be detected and the output level of this temperature detection element with a voltage level corresponding to a preset oxygen deficiency judgment temperature, and outputs an oxygen deficiency detection signal when the output level is below the voltage level. a timer that responds to the start of combustion of the lamp wick and disables the oxygen deficiency detection operation of the comparator for a certain period of time until the lamp wick achieves normal and stable combustion; and a timer that responds to the oxygen deficiency detection signal of the comparator. A portable kerosene stove characterized by being provided with a device.