JPH1073250A - Automatic fire extinguishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent affection on the performance of an instrument and ensure high reliability by restraining the fluctuation of a circuit resistance. SOLUTION: A temperature sensor 7, provided in the range unit of a table range, is provided with an operating shaft 17, to which a ferrite magnet 15, capable of being attracted to a temperature sensitive ferrite 12, is connected through a yoke 16, so as to be slidable up-and-down and energized downward by a returning spring 19. A neodymium magnet 21, arranged so as to have the polarity thereof in up-and-down direction, is fixed integrally to the lower position of a yoke 16. On the other hand, coils 22a, 22b, 22c are wound around the outer surface of a column with an interval between them respectively while a thermoelectric circuit 23 is constituted by connecting the coils 22a-22c in series to a thermocouple 8 and the exciting coil 6a of a solenoid valve 6 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic fire extinguisher provided in a burning appliance such as a table stove and capable of extinguishing a gas burner at a desired timing, for example, when the temperature of a pan bottom is overheated, during an earthquake, or when a timer is activated. .

[0002]

2. Description of the Related Art FIG. 8 shows an example of a conventional automatic fire extinguisher. The automatic fire extinguisher 30 is configured to prevent a tempura from being fired by a table stove, and operates by detecting a pan bottom temperature. First of all, a holder 31 protruding in the center of the stove
Inside, the temperature-sensitive ferrite 33 is provided on the back surface of the cap 32 that contacts the bottom of the pot, and the temperature-sensitive ferrite 33 attracts a magnet 35 to which an operating shaft 34 is connected below. The operating shaft 34 is urged downward by a return spring 38, and has a lower end provided with a coil of a magnet solenoid valve 40 for opening a gas flow path to a gas burner, and a thermocouple 41 disposed near the gas burner. And a micro switch 36 that opens and closes a thermoelectric circuit 39 formed by connecting the micro switch 36 in series. At an upper limit position where the magnet 35 is attracted to the temperature-sensitive ferrite 33, the micro switch 36 comes into contact with the switch plate 37 to turn on. Become. Therefore, when the temperature-sensitive ferrite 33 changes from ferromagnetic to paramagnetic when the Curie point is reached by the rise in the temperature of the pot bottom, the magnet 35 separates from the temperature-sensitive ferrite 33 by the urging force of the return spring 38 and drops downward. At the same time, the microswitch 36 also moves downward to
The FF is performed, the energization of the thermoelectric circuit 39 is stopped, the magnet electromagnetic valve 40 is closed, the gas supply is cut off, and the fire is automatically extinguished. On the other hand, a valve element for directly opening and closing the gas flow path is provided at the lower end of the operating shaft so as to be urged downward (in a valve closing direction). Then, a configuration is also adopted in which the valve body is closed by the bias and the gas flow path is shut off.

[0003]

In the above automatic fire extinguisher, the former has a considerably small circuit resistance of the thermoelectric circuit 39 of about 50 mΩ.
The contact resistance changes, that is, an increase in the contact resistance, cause a problem that affects the performance of the combustion appliance itself, such as poor ignition and deterioration of the throttle performance of the thermal power. Similarly, since the latter also has a structure in which the gas flow path is directly opened and closed, a high sealing load is required for the valve body, and the urging force in the valve closing direction is increased. However, on the contrary, it is necessary to increase the magnetic force of the magnet so that the magnet can be attracted to the temperature-sensitive ferrite against the urging force, so that the operation performance of the sensor deteriorates.

Accordingly, an object of the present invention described in claims 1 and 2 is to provide an automatic fire extinguisher which can suppress fluctuations in circuit resistance of a thermoelectric circuit and maintain a suitable operation performance without deteriorating equipment performance. It is to provide in a simple configuration.

[0005]

According to a first aspect of the present invention, an exciting coil of an electromagnetic valve arranged in a gas flow path is connected to a thermoelectric element arranged near a gas burner. A thermoelectric circuit for maintaining the supply of gas to the gas burner by adsorbing and holding the solenoid valve that has been forcibly opened by the thermoelectromotive force of the thermoelectric element, and a plurality of coils in the thermoelectric circuit; And one or a plurality of magnets which can be relatively approached or separated from the coils are provided, and the relative approaching or separating motion is applied to each coil or magnet at a desired timing for each coil. In order to sequentially induce an induced electromotive force in the opposite direction to the thermoelectromotive force of the thermoelectric element in each coil, reduce the forward current to the solenoid valve by their reverse current, and Valve can be closed It is characterized in that the.
In order to achieve the above object, the second invention of claim 2 is:
Two exciting coils are wound around the iron core of the solenoid valve arranged in the gas flow path, and one of the exciting coils is connected to a thermoelectric element arranged near the gas burner, and forcibly generated by the thermoelectromotive force of the thermoelectric element. The electromagnetic valve that has been opened is suction-held and held open to constitute a thermoelectric circuit that maintains gas supply to the gas burner, while the other excitation coil is connected to another plurality of coils and connected to those coils. By providing one or a plurality of magnets that can be relatively approached or separated from each other, by causing the coil or magnet to perform the relative approaching or separating motion at a desired timing for each coil in order, The induced electromotive force is continuously induced in each coil to energize the other exciting coil, and is excited in a direction opposite to that of the one exciting coil, and the attracting force of the solenoid valve is reduced by the back magnetomotive force. Let It is characterized in that to allow closing the solenoid valve.

According to a third aspect of the present invention, in addition to the object of the first aspect, the current supplied to the solenoid valve by the reverse current is provided in order to secure a current level at which the solenoid valve closes for a long time. The value of the reverse current is adjusted so as not to exceed the valve closing level on the reverse current side. According to the invention of claim 4, in addition to the object of claim 2, in order to secure a long magnetomotive force level at which the solenoid valve closes, the combined magnetomotive force generated in the solenoid valve by the back magnetomotive force is increased. The value of the back magnetomotive force is adjusted so as not to exceed the valve closing level on the back magnetomotive force side. In addition, the invention of claim 5 has, in addition to the objects of claims 1 to 4, in order to constitute an automatic fire extinguishing device that can be suitably used particularly for preventing a tempura fire of a table stove, wherein the magnet is one,
While connected via a connecting member to a second magnet adsorbing to a temperature-sensitive ferrite provided at a predetermined location as a temperature sensor, the plurality of coils are arranged on a coaxial straight line below the magnet, and the coil or The relative approach or separation movement of the magnet and its timing are obtained by an operation in which the second magnet separates from the temperature-sensitive ferrite in accordance with a change in magnetism due to a temperature rise of the temperature-sensitive ferrite. It is characterized by the following.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view of an automatic fire extinguisher configured on a table stove. The automatic fire extinguisher 1 is incorporated in a blinker main body 2 and is forcibly opened by a push operation of an ignition button 3 in the direction of an arrow to burner. A magnet electromagnetic valve 6 for opening a gas flow path to the main body 4, a temperature sensor 7 penetrating through the center of the burner head 5 and protruding upward, and being disposed near the burner head 5, detecting a flame to generate heat. A thermocouple 8 for supplying electric power to the magnet solenoid valve 6. First, the details of the temperature sensor 7 are shown in FIG. On the cylindrical support 10 erected on the fixed plate 9 inside the table stove,
A cylindrical holder 13 containing a heat-sensitive cap 11 on the top and a temperature-sensitive ferrite 12 on the back thereof,
It is externally slidable up and down. This holder 1
3 is urged upward by a compression spring 14 provided between the temperature-sensitive ferrite 12 and the expanded portion 10a at the upper part of the column 10, and a stopper 13a protruding from the inner surface of the holder 13 and the expanded portion 10a. The upper limit position is regulated by the locking with the above. Also, inside the support post 10,
A cylindrical yoke 16 holding the ferrite magnet 15 at the upper end
And an operating shaft 17 is connected below the yoke 16. The operating shaft 17 is provided with a lower flange 18.
When the temperature of the temperature-sensitive ferrite 12 is a ferromagnetic material before the Curie point (for example, 250 ° C.) is reached, the ferrite magnet is pressed by a return spring 19 provided between the ferrite magnet and the fixing plate 9. When the temperature of the temperature-sensitive ferrite 12 reaches the Curie point and turns into a paramagnetic material, the operating shaft 17 is returned to the upper limit position together with the yoke 16 against the bias of the return spring 19. When the urging force of the spring 19 exceeds, the ferrite magnet 15 separates from the temperature-sensitive ferrite 12, and the operating shaft 17 drops together with the yoke 16. Further, a neodymium magnet 21 whose polarity is arranged up and down is integrally mounted at a position below the yoke 16 on the operating shaft 17. The connection between the operating shaft 17 and the yoke 16 is performed by inserting the upper part of the operating shaft 17 having the retaining portion 17a into the yoke 16, and the partition plate 16a above the yoke 16 and the retaining portion 17a Are biased in directions that are separated from each other in the axial direction. Here, the support 10 and the yoke 16 are formed of a non-magnetic material. On the outer surface of the column 10, three coils 22a, 22b, and 22c are wound in the same winding direction at intervals. These coils 22a to 22c are
As shown in the lower part of FIG. 1, the thermocouple 8 and the exciting coil 6 a in the magnet solenoid valve 6 are respectively connected in series to form a thermoelectric circuit 23.

In the automatic fire extinguisher 1 constructed as described above, when a pot or the like is set on the hot pot, the holder 13 is pushed down against the bias of the compression spring 14, and the heat-sensitive cap 11 is placed on the bottom of the pot. The temperature of the pot bottom is transmitted to the temperature-sensitive ferrite 12 in close contact. At normal times when the temperature of the temperature-sensitive ferrite 12 does not reach the Curie point, as described above, the ferrite magnet 15 is attracted to the temperature-sensitive ferrite 12 to hold the operating shaft 17 at the position shown in FIG. It is located above the coil 22a. When the magnet electromagnetic valve 6 is forcibly opened by the push operation of the ignition button 3 and the gas burner is ignited, the thermoelectric circuit 23 is energized by the thermoelectromotive force of the thermocouple 8 that senses the flame, and the magnet electromagnetic valve 6 is turned on. Attraction current flows to the coil 6a of the magnetic solenoid valve 6, and the magnet solenoid valve 6 is kept open. When the extinguishment occurs, the power supply to the thermoelectric circuit 23 is stopped due to a decrease in the thermoelectromotive force of the thermocouple 8, and the magnet solenoid valve 6 is closed. On the other hand, when the temperature of the pot bottom rises and the temperature-sensitive ferrite 12 in the temperature sensor 7 reaches the Curie point, its magnetism changes from a ferromagnetic substance to a paramagnetic substance. It separates from the warm ferrite 12 and falls down together with the operating shaft 17. Then the operating shaft 1
The neodymium magnet 21 integrated with the magnet 7 also falls within the column 10, but the magnetic flux that changes with the movement of the neodymium magnet 21 crosses the coil 22a and induces electromotive force at both ends of the coil 22a. After passing through the coil 22a, the second and third coils 22b and 22c
Similarly, the same induced electromotive force is generated three times successively by approaching, passing, and falling to the lower limit position in FIG. The current due to these induced electromotive forces is
It is set to flow in the opposite direction to the adsorption current to the magnet solenoid valve 6 due to the thermoelectromotive force of the thermocouple 8 (set by the winding direction of the coils 22a to 22c, the polarity of the neodymium magnet 21, and the like). The adsorption current in the thermoelectric circuit 23 decreases, the magnet solenoid valve 6 closes, the gas supply stops, and the fire extinguishes automatically.

This operation will be described with reference to the graph of FIG. This figure shows a change with time of the attracting current to the magnet solenoid valve 6 during the operation of the automatic fire extinguisher (the forward current at the time of attraction is shown on the upper side and the reverse current is shown on the lower side). From the point P at which the neodymium magnet 21 starts to fall, the reverse current is generated by approaching the first coil 22a, so that the forward current decreases below the adsorption level, and the release level (the lower limit value at which the valve can be kept open) (point a) and becomes 0. The level of the reverse current further rises due to the increase of the reverse current, and after the reverse departure level exceeds the adsorption level (point b), the reverse current decreases due to the passage of the neodymium magnet 21 to the forward current side again. Invert and return to the original level (cycle A). That attraction current is between the forward side of the withdrawal level (a point) of the time shifts t ₁ to opposite side of the suction level (b point), the magnet solenoid valve 6 is to closed. Also without it closed here, so that the reverse current can be closed by the time t ₂ to reach the opposite side of the withdrawal level (c point) to a downward side of the suction level (d point) decreases. Cycles B and C are similarly generated by the subsequent approach and passage to the coil 22b and the coil 22c.
₃ , t ₄ and t ₅ , t ₆ can be obtained continuously with a time difference. Therefore, the chance that the magnet solenoid valve 6 can be closed increases, and the fire can be surely extinguished. Although each cycle has reached the value exceeding the suction level (point b) on the reverse current side here, the magnet solenoid valve 6 can also be attracted by the exceeded reverse current value. It is desirable to stop the lower limit in each cycle to the opposite departure level. As a result, the times T ₁ , T ₂ , and T ₃ from the forward release level (point a) to the forward suction level (point d) again in each cycle are the times when the magnet solenoid valve 6 can be released. Thus, a long valve closing time for each cycle can be secured.

In the above-described embodiment, the coils 22a to 22c are wound around the support 10 at intervals, and a reverse current is continuously obtained. However, as shown in FIG.
Even if the thermoelectric circuit 23a is formed by winding the reverse coils 24, 24 which are reversely wound with the reverse coil 22c, a forward current is generated in the reverse coils 24, 24 by electromagnetic induction, so that the coil 2
The reverse current in 2a to 22c is continuously generated with a time difference, and the same operation and effect as described above can be obtained. In the above description, a plurality of coils are arranged on a coaxial straight line, and one magnet is moved to obtain an induced electromotive force. However, a plurality of magnets are provided for each coil, and the coils are arranged in parallel. On the other hand, a configuration in which the magnets approach each other in order may be adopted. Similarly, the induced electromotive force can be obtained by moving the magnets and the coils away from each other, instead of approaching each other. Other ways to obtain the induced electromotive force effectively include increasing the number of turns of the coil, changing the shape of the magnet, and surrounding the coil with a ferromagnetic material such as iron. Both ends are short-circuited with a micro switch, and this is turned on by contact with a flange etc. when the operating shaft falls
By doing so, the forward current flowing to the magnet solenoid valve when the reverse current flows can be reduced, and the magnet solenoid valve can be effectively closed even with a small reverse current.

In the above-described embodiment, the coil of the temperature sensor is connected in series to the thermoelectric circuit. However, in the present invention, the electromagnetic valve is closed by obtaining the induced electromotive force by the change in the magnetic flux of the magnet with respect to the coil. 6 and 7 are also possible as long as the object is achieved. That is, as a second invention, an exciting coil 6a and a reverse exciting coil 26 which is reversely wound to the exciting coil 6a are wound around the iron core 25 of the magnet solenoid valve 6, respectively.
As described above, the exciting coil 6a is connected in series with the thermocouple 8 to form a thermoelectric circuit 23b, while the reverse exciting coil 26 is connected in series with the coils 22a to 22c of the temperature sensor 7. Therefore, in this case, the coil 2
2a to 22c, the electromagnetic solenoid valve 6
Generates a magnetomotive force in a direction opposite to the magnetomotive force due to the energization of the thermoelectric circuit 23b, the attraction force (combined magnetomotive force) to the attraction piece 28 connecting the valve body 27 decreases, and the valve body 27 closes. .
According to this configuration, the coils 22a to 22c are provided in the thermoelectric circuit 23b.
Need not be incorporated, and the variation of the circuit resistance can be suppressed, and the influence on the performance of the device can be more suitably prevented. Of course, also in the second invention, if the back magnetomotive force is set so as not to become too large, that is, the combined magnetomotive force does not exceed the valve closing level on the back magnetomotive force side, T ₁ to T ₁ described in FIG. longer be secured closing time in each cycle as T _3. Also, the one employing the reverse coil 24 as shown in FIG. 5 is similarly applicable.

In the above, the present invention has been described in connection with a temperature sensor in a table stove to constitute an automatic fire extinguishing device effective for preventing a tempura fire. However, the present invention is also related to a vibration sensor, a timer and the like. This makes it possible to arbitrarily configure an automatic fire extinguisher that extinguishes fire at a desired timing, such as an earthquake fire extinguisher or a timer fire extinguisher.

[0013]

According to the first and second aspects of the present invention, fluctuations in circuit resistance in a thermoelectric circuit composed of a thermoelectric element and a solenoid valve are reduced, thereby improving the performance of the appliance such as poor ignition and poor throttle characteristics. And a highly reliable automatic fire extinguisher that reliably extinguishes fire at a desired timing can be easily configured. In particular, a more reliable automatic fire extinguishing operation can be assured by generating the reverse current and the counter-electromotive force continuously plural times. According to the third and fourth aspects of the present invention, in addition to the effects of the first and second aspects, by adjusting the reverse current and the counter-electromotive force, the current for closing the solenoid valve and the level of the magneto-motive force can be secured for a long time. Therefore, the reliability of automatic fire extinguishing can be further improved. According to the fifth aspect of the present invention, in addition to the effects of the first to fourth aspects, an automatic fire extinguishing device that extinguishes a fire at a desired temperature can be easily configured in combination with a conventional temperature sensor. It can be suitably used for fire prevention.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an automatic fire extinguisher.

FIG. 2 is an explanatory diagram of a temperature sensor.

FIG. 3 is an explanatory diagram showing an operation state of a temperature sensor.

FIG. 4 is a graph showing a transition of a current to a magnet solenoid valve during an automatic fire extinguishing operation.

FIG. 5 is an explanatory diagram showing a modification of the automatic fire extinguishing device.

FIG. 6 is an explanatory view of a magnet solenoid valve according to the second invention.

FIG. 7 is a circuit diagram of the automatic fire extinguisher according to the second invention.

FIG. 8 is an explanatory view of a conventional automatic fire extinguishing device.

[Explanation of symbols]

1. Automatic fire extinguisher, 3. Ignition button, 6. Magnet solenoid valve, 7. Temperature sensor, 8. Thermocouple, 12.
・ Temperature-sensitive ferrite, 15 ・ ・ Ferrite magnet, 17 ・ ・
Working shaft, 21. neodymium magnet, 22a, 22b, 2
2c-coil, 23-thermoelectric circuit.

Claims (5)

[Claims] An exciting coil of an electromagnetic valve arranged in a gas flow path is connected to a thermoelectric element arranged near a gas burner,
A thermoelectric circuit for maintaining the gas supply to the gas burner by holding the solenoid valve that has been forcibly opened by suction by the thermoelectromotive force of the thermoelectric element and holding the valve open, and incorporating a plurality of coils in the thermoelectric circuit Together with one or more magnets which are relatively close to or away from the coils,
By causing each of the coils or magnets to perform the relative approach or departure movement in turn at desired timing for each coil, an induced electromotive force in the opposite direction to the thermoelectromotive force of the thermoelectric element is applied to each coil. An automatic fire extinguishing device, wherein the electromagnetic valve is continuously induced, a forward current to the electromagnetic valve is reduced by a reverse current thereof, and the electromagnetic valve can be closed. 2. An excitation coil is wound around an iron core of an electromagnetic valve disposed in a gas flow path, and one of the excitation coils is connected to a thermoelectric element disposed in the vicinity of a gas burner. Thereby, the electromagnetic valve that has been forcibly opened is held by suction-opening, and a thermoelectric circuit that maintains gas supply to the gas burner is configured, while the other excitation coil is connected to another plurality of coils. One or a plurality of magnets which can be relatively approached or separated from the coils are provided, and the relative approach or separation movement is performed on the coils or the magnets at desired timing in order for each coil. In this way, an induced electromotive force is continuously induced in each of the coils to energize the other exciting coil, and is excited in a direction opposite to the excitation by the one exciting coil. Adsorption An automatic fire extinguishing device, characterized in that the solenoid valve can be closed by reducing the force. 3. The automatic fire extinguisher according to claim 1, wherein the value of the reverse current is adjusted so that the current supplied to the solenoid valve by the reverse current does not exceed the valve closing level on the reverse current side. 4. The automatic magneto-motive force according to claim 2, wherein the value of the back magnetomotive force is adjusted so that the combined magnetomotive force generated in the solenoid valve by the back magnetomotive force does not exceed the valve closing level on the back magnetomotive force side. Fire extinguisher. 5. A single magnet, which is connected as a temperature sensor to a second magnet adsorbed on a temperature-sensitive ferrite provided at a predetermined location via a connecting member, while connecting the plurality of coils to the magnet. The second magnet is disposed on a coaxial straight line below and determines the relative approach or separation movement of the coil or the magnet and the timing thereof in accordance with a change in magnetism due to a temperature rise of the temperature-sensitive ferrite. The automatic fire extinguisher according to any one of claims 1 to 4, wherein the automatic fire extinguishing device is obtained by an operation of detaching from the warm ferrite.