JP3055610U - Pot overheating prevention device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To simplify the circuit configuration of a pot overheating prevention device, to reduce the number of parts without requiring a battery, and to simplify the structure of a temperature sensing unit for sensing the temperature of the pot. Therefore, the die cost is reduced, and a fail-safe function is provided. SOLUTION: A thermostat 23 arranged so as to be directly pressed against the bottom of the pan when the pan is put on a burner 16 of a gas stove, a thermocouple 17 which generates an electromotive force by combustion heat of the burner 16, and an electromotive force of the thermocouple 17 By electrically connecting the solenoid valve 12 that continues to supply gas to the ignited burner 16 in series, and when the pot is overheated, the thermostat 23 is opened to cut off the electromotive force of the thermocouple 17, and the solenoid is opened. Valve 12
Close to shut off gas supply.

Description

Description: BACKGROUND OF THE INVENTION [0001] The present invention relates to a pot for preventing a pan or the like cooked on a gas stove or a cooking vessel of this kind from overheating and causing a fire or the like. The present invention relates to an overheat prevention device. 2. Description of the Related Art A conventional device of this type will be described with reference to FIGS. First, FIG. 7 shows a temperature detector 1 for detecting the temperature at the bottom of the pan, and a temperature sensor, for example, a thermistor 3 is fixed to the inner surface of the top plate of the aperture case 2 in close contact with its terminal 3a. Is connected to the withdrawal cord 4. One end of a stepped case 5 is fixed to the aperture case 2, and a two-stage aperture case 6 slidable in the axial direction with respect to the stepped case 5 is provided at the other end. A coil spring 7 is interposed between the diaphragm case 2 and the two-stage diaphragm case 6. The two-stage aperture case 6 has its leg 6a fixed to an angle 8 of a gas stove by a fitting 9 as shown in FIG. FIG. 9 shows a contact state between the pot 11 placed on the gas stove 10 of the gas stove and the temperature detector 1. When the pan 11 is not placed, the temperature detector 1 pushes the aperture case 2 up against the two-stage aperture case 6 fixed to the angle 8 by the urging force of the coil spring 7, and FIG. As shown by the dashed line, it protrudes above the virtues 10. Then, when the pot 11 is placed on the gode 10, the squeezing case 2 is pushed down at the bottom of the pot 11 against the urging force of the coil spring 7. Therefore, the upper surface of the squeeze case 2 to which the thermistor 3 is closely fixed is pressed against the bottom of the pan 11 to detect the temperature of the bottom of the pan. FIG. 10 shows an electric circuit of a conventional pot overheating prevention device, in which 12 is a solenoid valve with a hand switch, 13 is a switch linked to the hand switch, and a high voltage generating circuit 14 for ignition is connected to a battery. 15 is connected. Reference numeral 16 denotes a gas stove burner in which the temperature detector 1 having the thermistor 3 and the thermocouple 17 are arranged. The thermistor 3 and the thermocouple 17 are connected to a controller 18 for controlling burner combustion. Next, the operation of the conventional example will be described. When the hand switch is pressed, the solenoid valve 12 is opened mechanically to supply gas to the burner 16, and at the same time, the battery 15 is connected to the high voltage generating circuit 14 via the switch 13, and the burner 16 is ignited. The burner 16 heats the thermocouple 17 by the heat of combustion, and the thermocouple 17 keeps the solenoid valve 12 open by the electromotive force of the heat and continues to supply gas. When the combustion of the burner 16 stops, the electromotive force of the thermocouple 17 disappears, the solenoid valve 12 closes, and the supply of gas stops. [0006] Here, when the pot 11 over the gotoku 10 is overheated, the thermistor 3 detects the temperature. The controller 18 controls the solenoid valve 12 based on the detection signal to close the gas passage. Thus, overheating of the pot can be prevented. However, in the above-mentioned conventional pot overheating prevention device, the controller 18 controls the solenoid valve 12 by inputting the detection signal of the thermistor 3 and the electromotive force of the thermocouple 17. Therefore, the number of parts is large, the configuration is complicated, and a power supply (battery) for operating the controller 18 is required, and the parts cost is high. In the temperature detector 1, the draw case 2, the stepped case 5, and the two-step draw 6 are formed by deep drawing, which requires advanced technology, and the die cost is high. Was very expensive. Further, considering the reliability and safety of the system, as shown in (Table 1), failure modes include open / short of an element or a circuit and large / small change in resistance value. In the case of the conventional example, if the sensor (thermistor 3) is opened, the resistance value becomes infinite, which is dangerous because the solenoid valve is kept open by the control by the controller and the gas continues to flow. The same is true even if the resistance value greatly changes. On the other hand, a short circuit of the sensor is safe because the controller closes the solenoid valve to stop the gas, and the same is true when the change in the resistance value is small. On the other hand, when the output of the controller is open, the solenoid valve is closed and the gas is stopped, so it is safe. Even when the change in the resistance value is large, it is almost safe. When the output of the controller is short-circuited, the solenoid valve is kept open and the gas continues to flow, which is dangerous. The same applies to the case where the change in the resistance value is small. [Table 1] Therefore, as a comprehensive judgment of this type of system in which the output operation of the system is determined by the synergistic operation of the sensor and the controller, in the same failure mode, even if one is safe, the other is not safe. In this failure mode, safety or reliability becomes poor. The present invention solves such a conventional problem, and has a simple circuit configuration, does not require a battery, and therefore has a small number of parts and a temperature sensor for sensing the temperature of the pan. It has a so-called fail-safe function that simplifies the structure of the part, reduces the cost of the mold, and maintains the operation direction in the case of an abnormality and the safety even if some equipment fails. An object of the present invention is to provide a pot overheating prevention device. Means for Solving the Problems To achieve this object, the apparatus for preventing overheating of a pot according to the present invention is arranged such that the pot is directly pressed against the bottom of the pot when the pot is placed on the gas stove. A thermostat, a thermocouple that generates an electromotive force by the combustion heat of the gas stove, and a solenoid valve that continues to supply gas to the ignited gas stove by the electromotive force of the thermocouple, wherein the thermostat, the thermocouple, and the solenoid valve Are electrically connected in series, and when the pot overheats, the thermostat opens to cut off the electromotive force of the thermocouple, close the solenoid valve, and cut off the gas supply. Things. According to the above configuration, the solenoid valve is mechanically opened by the hand switch, gas is supplied to the gas stove, and after ignition, the solenoid valve is kept open by the electromotive force of the thermocouple, Continue burning. When the pot is overheated, a thermostat that detects the temperature of the pot opens to shut off the electromotive force of the thermocouple, close the solenoid valve, and cut off gas supply. As described above, the device for preventing overheating of the pot of the present invention is composed of a series circuit of the thermostat, the thermocouple and the solenoid valve, so that the number of parts is small and the configuration is extremely simple. Since it is not a controller control method as in the conventional example, no battery is required. Further, the thermostat is hermetically sealed, and has a fail-safe structure in which the contact spring is pushed in one direction during abnormal operation when the pot is overheated, and the contact is separated. Therefore, it is hardly affected by the external atmosphere and has excellent safety. The thermostat has a terminal connected to a lead cord, and is installed at the tip of the temperature sensor. The temperature sensor has a substantially cylindrical case having one end in contact with the lower peripheral portion of the lower surface of the thermostat, and an aperture case for projecting a thermosensitive surface of the thermostat from the top to couple and fix the thermostat and the case. One end is fixed to the angle of the gas stove and the other end is inserted into the other end of the case, and is interposed between the lower surface of the thermostat and the holding base to urge the thermostat upward. And a coil spring. According to this configuration, the substantially cylindrical case is obtained by processing a pipe, and since the holding table is a general press-processed product, unlike the conventional case, it does not require many deep drawing operations. The shape is simple, and the cost of the mold can be greatly reduced. Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a temperature sensor 21 for detecting the temperature at the bottom of a pot in one embodiment of the present invention. An exploded perspective view of the temperature sensor 21 is shown in FIG. 4, and will be described below with reference to FIG. The temperature sensor 21 has a thermosensitive surface of a thermostat 23 that has been hermetically projected from the top of an aperture case 22 without a top plate. The thermostat 23 is provided with a terminal 23a for external connection, and a lead cord 24 is connected to the terminal 23a. Reference numeral 25 denotes a substantially cylindrical case having one end abutting on the peripheral edge of the lower surface of the thermostat 23. The projection 25 or the cut-and-raised claw 22a formed on the aperture case 22 is engaged with a hole 25a formed on one end thereof. By joining, the thermostat 23 and the case 25 are connected and fixed. 26 is a holding table having one end fixed to an angle 28 of the gas stove with a screw 29 and the other end inserted into the other end of the case 25; and 27 is interposed between the lower surface of the thermostat 23 and the holding table 26. , A coil spring that urges the thermostat 23 upward. The cut-and-raised claw 25b formed on the case 25 is engaged with the window 26a provided on the holding base 26 so that the thermostat 23 does not rotate and the drawer cord 24 is twisted or the terminal 23a is not bent. Let me. A gap 30 is provided between the inner wall of the case 25 and the coil spring 27, and the case 25 can be inclined to some extent in all directions around the front, rear, left and right. This is so that the thermosensitive surface of the thermostat 23 can be fitted even if the bottom of the pot placed on Gotoku is slightly inclined. FIG. 5 shows an example in which two legs are provided to stabilize the holding table. FIG. 2 shows the internal structure of the thermostat 23 hermetically sealed. A bimetal 35 having a push rod 34 is arranged near the top of the case 33, and the bimetal 35 is in a normal state and is in an upwardly convex state as shown in FIG. As shown in FIG. 2 (b), the thermostat 23 that has sensed overheating of the pot is configured such that the bimetal 35 is curved so as to protrude downward, the push rod 34 pushes down the contact spring 36, and the contacts are separated. It has become. FIG. 3A shows the state of the temperature sensor 21 when the pot 11 is not placed on the gas stove 10 of the gas stove. At this time, due to the urging force of the coil spring 27, the thermostat 23 is pushed up together with the surrounding case against the holding base 26 fixed to the angle 28, and protrudes upward from the gode 10. Then, when the pot 11 is placed on the goto 10, the thermostat 23 is pushed down at the bottom of the pot 11 against the urging force of the coil spring 27 as shown in FIG. Therefore, the thermostat 23 has its temperature-sensitive surface pressed against the bottom of the pan 11 and detects the temperature at the bottom of the pan. FIG. 6 shows an electric circuit of the apparatus for preventing overheating of the pot according to the present embodiment. Reference numeral 12 denotes a solenoid valve with a hand switch, 16 denotes a burner, and 17 denotes a thermocouple. . Reference numeral 23 denotes a thermostat, and reference numeral 31 denotes an ignition piezoelectric element that operates in conjunction with the hand switch. Here, the thermostat 23, the thermocouple 17, and the solenoid valve 12 are electrically connected in series. Next, the operation in the present embodiment will be described. When the hand switch is pressed, the solenoid valve 12 is opened mechanically to supply gas to the burner 16 and, at the same time, a spark discharge is generated by hitting the piezoelectric element 31 to ignite the burner 16. The burner 16 heats the thermocouple 17 by the heat of combustion, and the thermocouple 17 keeps the solenoid valve 12 open by the electromotive force of the heat to continue supplying gas. When the combustion of the burner 16 stops, the electromotive force of the thermocouple 17 disappears, the solenoid valve 12 closes, and the supply of gas stops. In this case, when the pot 11 placed on the pot 10 is overheated and abnormal, the thermostat 23 that senses the temperature of the pot 11 is opened to cut off the electromotive force of the thermocouple 17. As a result, the solenoid valve 12 is closed and the supply of gas is cut off. In this manner, overheating of the pot can be prevented, and occurrence of a fire or the like can be prevented. The case 25 constituting the temperature sensor 21 has a substantially cylindrical shape, and can be easily processed from a pipe. In addition, the holding table 26 is obtained by a general press working, and therefore, only the drawing case 22 for connecting and fixing the thermostat 23 to the case 25 is required to be drawn by using a mold. can do. In addition, since the processing technique is also ordinary drawing, the yield is good. Therefore, the manufacturing cost of the mechanical component can be reduced. Considering the reliability and safety of the thermostat system, as shown in (Table 1), the failure mode includes the thermostat open and short circuit. When open, the circuit is opened immediately and the solenoid valve is closed to cut off gas supply, which is safe. On the other hand, in the case of a short-circuit, welding of the contacts is generally considered. However, in the configuration of the present invention, there is no welding because the electromotive force of the thermocouple is very small and the maximum current is 0.4 A. In addition, a short may be considered due to a deformation factor of the case due to an external force. However, even when the top of the case is depressed, the structure is such that the contacts are separated, so that it is safe. The present invention has been realized by developing a thermostat embodying such a fail-safe concept. As described above, according to the present invention, the configuration of the apparatus for preventing overheating of the pot is simplified, and the number of parts can be reduced, and the cost of parts can be reduced by not using batteries. it can. Further, the members constituting the temperature sensor can also be manufactured by drawing without using an expensive mold, so that significant cost reduction can be achieved. In addition, the thermostat is hermetically sealed, so that it is not affected by the external atmosphere.Moreover, when the pot is overheated, the thermostat detects the temperature of the pot and opens the circuit. Therefore, a highly safe pot overheating prevention device having a fail-safe function can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a temperature sensor according to an embodiment of the present invention. FIG. 2 is a diagram showing an internal structure of a thermostat according to an embodiment of the present invention. FIG. 4 is a view showing a relationship between a temperature sensor and a pot in one embodiment of the present invention. FIG. 4 is an exploded perspective view of the temperature sensor in one embodiment of the present invention. FIG. 5 is a view showing another example of a holding table. FIG. 6 is a circuit configuration diagram of the apparatus for preventing overheating of the pot in one embodiment of the present invention. FIG. 7 is a configuration diagram of a conventional temperature detector. FIG. 8 shows a mounting structure of the conventional temperature detector on a gas stove. FIG. 9 is a diagram showing the relationship between a conventional temperature detector and a pan. FIG. 10 is a circuit configuration diagram of a conventional pan overheat prevention device. [Description of References] 11 pan 12 solenoid valve 16 burner 17 thermocouple 21 Temperature sensor 22 Aperture case 23 Thermostat 24 Pull-out cord 25 Case 26 Holder 27 Coil spring 31 Piezoelectric element 34 Push rod 35 Bimetal 36 Contact spring

Claims (1)

[Claim 1] A thermostat arranged so as to be directly pressed against the bottom of a pot when a pot or the like is placed on the gas stove, and a thermocouple that generates an electromotive force by the combustion heat of the gas stove And a solenoid valve for continuously supplying gas to the ignited gas stove by the electromotive force of the thermocouple, wherein the thermostat, the thermocouple and the solenoid valve are electrically connected in series, and the pot or the like is overheated. When the thermostat is opened, the thermostat is opened to shut off the electromotive force of the thermocouple, and the solenoid valve is closed to cut off the gas supply. 2. The apparatus according to claim 1, wherein the thermostat is hermetically sealed. 2. The overheating of the thermostat according to claim 1, wherein the thermostat is of a fail-safe type in which a contact spring is pressed in one direction when an abnormal operation occurs when the pot or the like is overheated and the contact is opened. Prevention device. 4. A thermostat (23) having a lead cord (24) connected to its terminal and a temperature sensor (21).
The temperature sensor (21) is installed at the tip of the thermostat (23). The thermostat (23) has a substantially cylindrical case (25) with one end abutting on the lower peripheral edge of the thermostat (23). An aperture case (22) for projecting a warm surface and connecting and fixing the thermostat (23) and the case (25), and one end of an angle of a gas stove (28)
, The other end of which is inserted into the other end of the case (25), and the thermostat (23) interposed between the lower surface of the thermostat (23) and the holder (26). 4. A pan overheating prevention device according to claim 1, 2, or 3, further comprising a coil spring (27) for urging the upper portion of the pan upward.