JP3801746B2 - Pan bottom temperature sensor and gas stove using it - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pan bottom temperature sensor that detects the temperature by contacting a bottom surface of a cooking container such as a pan, and a gas stove using the pan bottom temperature sensor.
[0002]
[Prior art]
Conventionally, as a gas stove with an overheat prevention function, it has a pan bottom temperature sensor that detects the temperature of the cooking container by contacting the bottom of the cooking container heated by a burner, and the temperature of the cooking container rises abnormally due to empty cooking etc. It is known to extinguish the burner when you do.
[0003]
This pan bottom temperature sensor is configured by providing a thermistor as a heat sensitive element in a casing that is in contact with the bottom surface of the cooking container, and the thermistor is connected to a controller comprising a microcomputer.
Then, a switch controlled by the controller intervenes in a safety valve circuit that connects a thermocouple that detects the flame of the burner and an electromagnetic safety valve interposed in the gas supply path of the burner, and the controller cooks based on the resistance change of the thermistor. The container temperature is calculated, and when the temperature becomes abnormally high, the switch is turned off by a signal from the controller, the electromotive force input from the thermocouple to the electromagnetic safety valve is cut off, and the electromagnetic safety valve is closed. The burner is extinguished.
[0004]
[Problems to be solved by the invention]
Since the pan bottom temperature sensor using the conventional thermistor requires a controller, there is a problem that the cost increases.
In this case, if you use a pan-bottom temperature sensor that uses a bimetal switch as the thermal element and place the bimetal switch in series with the thermocouple in the safety valve circuit, the bimetal switch can be turned off due to the abnormally high temperature of the cooking container, and the burner can be extinguished. , No controller is required.
However, in bimetal switches, there is a possibility of causing an on-failure that remains on due to welding of the switch part operated by bimetal, and if an on-failure occurs, the burner cannot be extinguished even if the temperature becomes abnormally high, and reliability is increased. There is a defect that is missing.
[0005]
In view of the above points, the present invention provides a pan bottom temperature sensor that can ensure reliability using a bimetal switch, and further provides an inexpensive gas stove having an overheat prevention function. .
[0006]
[Means for Solving the Problems]
In order to solve the above problem, the pan bottom temperature sensor of the present invention is a pan bottom temperature sensor for detecting the temperature of the cooking vessel, and includes a casing that comes into contact with the bottom surface of the cooking vessel and a thermal element provided in the casing. In this embodiment, the thermal element is composed of a bimetal switch, and the bimetal switch includes a bimetal disposed in the vicinity of the back surface of the upper plate of the casing, and a switch unit disposed below the bimetal switch so as to open and close in cooperation with the bimetal. The thermal fuse is arranged in the casing in the vicinity of the back surface of the upper plate, separated from the bimetal laterally, while the bimetal case for storing the bimetal and the switch part is arranged in the casing, The head of the bimetal case is welded to the back surface of the upper plate constituting the head of the casing, and the outer surface of the bimetal case is The case bracket the temperature fuse can be mounted after welding provided, are connected in series thermal fuse mounted to the bracket to the switch portion of the bimetal switch.
[0007]
In addition, the gas stove of the present invention uses the pan bottom temperature sensor of the present invention, and a thermocouple for detecting the flame of the burner that heats the cooking container, and a thermocouple that is interposed in the gas supply path to the burner. A series connection circuit of a bimetal switch and a thermal fuse is interposed in series with a thermocouple in a safety valve circuit that connects an electromagnetic safety valve held open by electric power.
According to this, when the cooking container becomes abnormally hot, the bimetal switch of the pan bottom temperature sensor is turned off, the input of the electromotive force from the thermocouple to the electromagnetic safety valve is cut off, and the burner is extinguished. Even if an on-failure of the bimetal switch occurs, the thermal fuse is blown, so that the electromotive force input from the thermocouple to the electromagnetic safety valve is cut off, and the burner is reliably extinguished.
[0008]
When the temperature fuse is blown, the pan bottom temperature sensor becomes unusable. Therefore, the temperature at which the temperature fuse is blown is set slightly higher than the temperature at which the bimetal switch is turned off, and the temperature fuse is blown only when the bimetal switch is on.
[0009]
By the way, the bimetal switch is composed of a bimetal, a switch portion operated by the bimetal, and a bimetal case for housing the bimetal and the switch portion, and the back surface of the upper plate constituting the head of the casing of the pan bottom temperature sensor. Weld the head of the bimetal case to install the bimetal switch in the casing.
[0010]
The thermal fuse is held by a bracket provided in the casing. In this case, if a bracket for the thermal fuse is attached to the outer surface of the bimetal case, the bimetal case and the bracket are attached to the upper plate as one unit component. It can be attached, and the assembly of the pan bottom temperature sensor is improved. However, if the bimetal case is welded to the upper plate with the thermal fuse attached to the bracket, the thermal fuse may be adversely affected by heat during welding. Therefore, it is desirable that the bracket be configured so that a thermal fuse can be attached to the bracket after the bimetal case is welded to the upper plate.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a gas stove with an overheat prevention function, and the burner 2 faces the opening 1a formed in the top plate 1 on the stove body (not shown) and is placed on the top plate 1. The cooking container P on the five virtues 3 can be heated by the burner 2.
[0012]
The burner 2 includes a burner body 20 having a mixing tube portion 20a and an annular burner head portion 20b, and an annular burner cap 21 mounted on the burner head portion 20b.
[0013]
And when the pan bottom temperature sensor 4 which protrudes upwards through each inner diameter part of the burner cap 21 and the burner head part 20b is provided and the pan bottom temperature sensor 4 detects the abnormally high temperature of the bottom face of the cooking container P, a burner is mentioned by the means mentioned later. 2 is extinguished and the cooking container P is prevented from overheating.
The pan bottom temperature sensor 4 is provided at the upper end portion of the support rod 6 fixed to the stove body via the mounting bracket 5. Further, the burner cap 21 is provided with a heat shield cylinder 21 a that surrounds the pan bottom temperature sensor 4, so that the radiant heat from the flame of the burner 2 acts on the pan bottom temperature sensor 4.
[0014]
As shown in FIG. 2, the pan bottom temperature sensor 4 includes a cylindrical casing 41 having a cap-shaped upper plate 40 attached to the head, and the casing 41 is attached to the upper end of the support rod 6 so as to be movable up and down. A coiled spring 42 is interposed between a spring receiver 60 comprising a flange attached to the upper end of the support rod 6 and the upper plate 40.
Thus, the pan bottom temperature sensor 4 is biased upward by the spring 42, and the upper plate 40 comes into contact with the bottom surface of the cooking container P on the virtues 3. The casing 41 is formed in a stepped shape having a lower small-diameter portion 41 a, and does not move any further when the upper end of the small-diameter portion 41 a abuts against the spring receiver 60.
[0015]
The upper plate 40 is caulked and coupled to the casing 41, and a bimetal switch 43 as a heat sensitive element is attached to the back surface thereof.
The bimetal switch 43 includes a disc-shaped bimetal 430 that abuts against an annular bead 430a provided in the head, and a switch unit 432 operated by the bimetal 430, in a cylindrical bimetal case 431 whose head is closed. The bimetal switch 43 is attached to the upper plate 40 by spot welding the head of the bimetal case 431 to the back surface of the upper plate 40. Then, the opening part opposite to the head part of the bimetal case 431 is sealed with a lid member 433 and sealed with an inert gas to protect the bimetal 430 and the switch part 432.
[0016]
The switch unit 432 includes a fixed contact 432a attached to the upper end of one terminal pin 434 of a pair of terminal pins 434 and 434 inserted in the lid member 433, and a movable spring plate attached to the upper end of the other terminal pin 434. The rod 435 that is in contact with the lower surface of the central portion of the bimetal 430 is brought into contact with the movable contact piece 432b through the guide member 436 in the bimetal case 431.
[0017]
The bimetal 430 is normally in a downwardly convex curved state, the movable contact piece 432b is pushed downward via the rod 435 and comes into contact with the fixed contact 432a, and the bimetal switch 43 is turned on. On the other hand, when the temperature of the bimetal 430 becomes equal to or higher than the predetermined set temperature, the bimetal 430 is inverted upwardly, the movable contact piece 432b is separated from the fixed contact 432a by its own elastic restoring force, and the bimetal switch 43 is turned off. become.
[0018]
A temperature fuse 44 connected in series to the bimetal switch 43 is provided in the casing 41 of the pan bottom temperature sensor 4. In this case, the bracket 45 for the thermal fuse 44 can be attached to the back surface of the upper plate 40. However, in this embodiment, the bracket 45 is attached to the outer surface of the bimetal case 431, and the bimetal case 431 and the bracket 45 are connected to each other. It is designed to be attached to the upper plate 40 as one unit part. As shown in FIG. 3, the bracket 45 includes a pocket portion 45a that can store the thermal fuse 44 from the side opposite to the upper plate 40, and a bendable locking piece that prevents the thermal fuse 44 from being detached from the pocket portion 45a. And a fixing tongue piece 45c attached to the outer surface of the bimetal case 431. The bracket 45 is attached to the outer surface of the bimetal case 431 at the fixing tongue piece 45c by spot welding.
[0019]
When assembling the pan bottom temperature sensor 4, first, the head of the bimetal case 431 is spot-welded to the back surface of the upper plate 40, and then turned upside down so that the upper plate 40 faces downward as shown in FIG. In this state, in the bimetal case 431, the bimetal switch 430, the guide member 436 assembled with the rod 435, and the lid member 433 assembled with the switch unit 432 are sequentially mounted, and the bimetal switch 43 is assembled. The thermal fuse 44 is accommodated in the pocket portion 45a, and the locking piece portion 45b is bent to prevent the thermal fuse 44 from coming off. In this way, by attaching the temperature fuse 44 to the bracket 45 after spot welding the bimetal case 431 to the upper plate 40, it is possible to prevent the temperature fuse 44 from being adversely affected during spot welding.
[0020]
Next, one of the pair of terminal pins 434 and 434 inserted in the lid member 433 is connected to one of the pair of fuse terminals 44a and 44a of the thermal fuse 44, and further, the other terminal pin 434 and one pair are connected. One of the lead wires 46, 46 is connected, and the other fuse terminal 44 a and the other lead wire 46 are connected.
[0021]
Next, the casing 41 is extrapolated to the support rod 6 and the lead wires 46 and 46 are inserted into the hollow support rod 6 through the inner diameter portion of the spring 42 with the spring 42 placed on the spring receiver 60. Then, the upper plate 40 is pushed down so that the bimetal switch 43 and the thermal fuse 44 are accommodated in the inner diameter portion of the spring 42, and the peripheral portion of the upper plate 40 is caulked and joined to the upper end portion of the casing 41 while the spring 42 is lightly compressed.
Thereby, the pan bottom temperature sensor 4 in which the bimetal switch 43 and the temperature fuse 44 are connected in series can be assembled.
[0022]
Referring to FIG. 1, an electromagnetic safety valve 7, a main valve 8 that is opened and closed by a point-extinguishing operation, and a flow rate adjusting valve 9 are provided in series in the gas supply path of the burner 2 in order from the upstream side. .
The electromagnetic safety valve 7 includes an electromagnet 7 a connected to the thermocouple 10 facing the flame detection combustion portion of the burner 2, and the electromagnetic safety valve 7 is held open by the electromotive force of the thermocouple 10. The thermocouple 10 is fixed to a mounting bracket 5 common to the support rod 6.
[0023]
Here, one of the pair of lead wires 46, 46 led out below the support rod 6 is connected to one terminal of the thermocouple 10, and the other lead wire 46 and the other terminal of the thermocouple 10 are Each is connected to a pair of terminals of the electromagnet 7a. Thus, a series connection circuit of the bimetal switch 43 and the thermal fuse 44 is interposed in series with the thermocouple 10 in the safety valve circuit connecting the thermocouple 10 and the electromagnetic safety valve 7.
[0024]
In such a circuit, when the cooking container P reaches an abnormally high temperature, the bimetal switch 43 is turned off, the electromotive force of the thermocouple 10 is not input to the electromagnetic safety valve 7, and the gas supply is shut off by closing the electromagnetic safety valve 7, Burner 2 is extinguished.
[0025]
Further, even if an ON failure occurs due to welding of the fixed contact 432a and the movable contact piece 432b in the bimetal switch 43, the input of the electromotive force of the thermocouple 10 to the electromagnetic safety valve 7 is cut off by the melting of the temperature fuse 44, and the electromagnetic The burner 2 is reliably extinguished by closing the safety valve 7.
[0026]
In this case, the temperature at which the temperature fuse 44 is blown is set to a temperature (eg, 270 ° C.) slightly higher than the temperature at which the bimetal switch 43 is turned off (eg, 250 ° C.) so that the temperature fuse 44 is blown only when the bimetal switch 43 is on. To do.
[0027]
【The invention's effect】
As is apparent from the above description, according to the present invention, since a bimetal switch is used as a heat sensitive element of the pan bottom temperature sensor, a controller is not required and the cost is low, and even if an on failure of the bimetal switch occurs, a temperature fuse The burner can reliably extinguish the fire and ensure reliability.
[Brief description of the drawings]
FIG. 1 is a cut-away side view of a gas stove using the pan-bottom temperature sensor of the present invention. FIG. 2 is a cut-off side view of an example of a pan-bottom temperature sensor of the present invention. Perspective view [Explanation of symbols]
P Pan (cooking vessel) 2 Burner 4 Pan bottom temperature sensor 40 Upper plate 41 Casing 43 Bimetal switch (thermal element)
430 Bimetal 431 Bimetal case 432 Switch 44 Thermal fuse 45 Bracket 7 Electromagnetic safety valve 10 Thermocouple

Claims (2)

In a pan bottom temperature sensor for detecting the temperature of the cooking container, comprising a casing that contacts the bottom surface of the cooking container, and a thermal element provided in the casing,
While configuring the thermal element with a bimetal switch,
The bimetal switch is composed of a bimetal disposed in the vicinity of the back surface of the upper plate of the casing, and a switch portion disposed below the bimetal in order to open and close in cooperation with the bimetal.
Inside the casing, in the vicinity of the back surface of the upper plate, a thermal fuse is arranged laterally away from the bimetal ,
Inside the casing, a bimetal case that houses the bimetal and the switch part is arranged,
Welding the head of the bimetal case to the back of the upper plate constituting the head of the casing;
The outer surface of the bimetal case is provided with a bracket that can be fitted with a thermal fuse after the bimetal case is welded.
A temperature sensor mounted on the bracket is connected in series to a switch portion of a bimetal switch. A gas stove having a pan bottom temperature sensor according to claim 1 Symbol placement, and a thermocouple for detecting the flame of the burner for heating the cooking vessel, is interposed in the gas supply passage to the burner, the thermocouple emf A gas stove in which a series connection circuit of the bimetal switch and the thermal fuse is interposed in series with a thermocouple in a safety valve circuit that connects an electromagnetic safety valve held in an open state.

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