JPH1194245A - Pan bottom temperature sensor and gas cooker using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pan bottom temperature sensor in which a less-expensive sensor is attained by eliminating a controller under application of a bimetal switch acting as a heat sensitive element and its reliability in operation can by assured even in the event of turned-on trouble of the bimetal switch. SOLUTION: A heat sensitive element arranged in a casing 431 of a pan bottom temperature sensor abutted against the bottom surface of a cooking container is constituted by a bimetal switch 43 and then a temperature fuse 44 connected in series with the bimetal switch 43 is arranged in the casing 41. In a gas cooking device provided with the pan bottom temperature sensor 4, a series-connected circuit having the bimetal switch 43 and the temperature fuse 44 is arranged in series with a thermocouple in a safety valve circuit for use in connecting the thermocouple and a solenoid safety valve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pot bottom temperature sensor for detecting the temperature by contacting the bottom of a cooking vessel such as a pot, and a gas stove using the pot bottom temperature sensor.

[0002]

2. Description of the Related Art Conventionally, as a gas stove having a function of preventing overheating, a pot bottom temperature sensor for detecting the temperature of a cooking container by contacting the bottom surface of the cooking container heated by a burner has been provided. It is known to extinguish a burner when the temperature rises abnormally.

[0003] The pan bottom temperature sensor is constituted by providing a thermistor as a heat-sensitive element in a casing which is in contact with the bottom surface of the cooking vessel, and the thermistor is connected to a controller composed of a microcomputer. Then, a switch controlled by the controller is interposed 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 performs cooking based on a change in resistance of the thermistor. Calculate the temperature of the container, when the temperature becomes abnormally high, turn off the switch by the signal from the controller, cut off the input of electromotive force from the thermocouple to the electromagnetic safety valve, and close the electromagnetic safety valve I am extinguishing the burner.

[0004]

The pan bottom temperature sensor using the above-mentioned prior art thermistor requires a controller, so that there is a problem that the cost is increased. in this case,
If a bimetal switch is used in series with a thermocouple in a safety valve circuit using a pan bottom temperature sensor that uses a bimetal switch as a heat-sensitive element, the bimetal switch can be turned off and the burner can be extinguished due to abnormally high temperatures in the cooking vessel. It becomes unnecessary. However, with bimetal switches, there is a possibility that an on failure will occur which remains on due to welding of the switch operated by the bimetal, and if an on failure occurs, the burner cannot be extinguished even at an abnormally high temperature, resulting in increased reliability. There are missing defects.

[0005] In view of the above, the present invention provides a pan bottom temperature sensor which can ensure reliability using a bimetal switch, and further provides an inexpensive gas stove having an overheating prevention function. It is an issue.

[0006]

Means for Solving the Problems In order to solve the above problems,
In the pan bottom temperature sensor of the present invention, the heat-sensitive element provided in the casing abutting on the bottom surface of the cooking vessel is constituted by a bimetal switch, and the temperature fuse connected in series to the bimetal switch is provided in the casing.

Further, a gas stove according to the present invention comprises a thermocouple for detecting a flame of a burner for heating a cooking vessel using the pan bottom temperature sensor of the present invention, and a thermoelectric device provided in a 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 that is held open by a pair of electromotive forces. According to this, when the temperature of the cooking vessel becomes abnormally high, 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 occurs in the bimetal switch, the thermal fuse is blown, so that the input of the electromotive force from the thermocouple to the electromagnetic safety valve is cut off and the burner is reliably extinguished.

When the thermal fuse is blown, the pan bottom temperature sensor cannot be used. Therefore, the temperature at which the thermal fuse blows is set slightly higher than the temperature at which the bimetal switch turns off, so that the thermal fuse blows only when the bimetal switch turns on.

The bimetal switch comprises a bimetal, a switch operated by the bimetal, and a bimetal case accommodating the bimetal and the switch. The bimetal switch forms a head of the casing of the pan bottom temperature sensor. Weld the head of the bimetal case to the back of the board and mount the bimetal switch in the casing.

[0010] The thermal fuse is held by a bracket provided in the casing. In this case, if a thermal fuse bracket is mounted on the outer surface of the bimetal case, the bimetal case and the bracket are formed as one unit part. It can be attached to the upper plate, and the assemblability 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 PREFERRED EMBODIMENTS FIG. 1 shows a gas stove having an overheating prevention function. A burner 2 faces an opening 1a formed in a top plate 1 on a vessel (not shown) of the stove. The cooking vessel P on the top 3 placed on the top plate 1 can be heated by the burner 2.

The burner 2 includes a burner main body 20 having a mixing tube section 20a and an annular burner head section 20b, and an annular burner cap 21 mounted on the burner head section 20b.
It is composed of

A pot bottom temperature sensor 4 is provided which projects upward through the inner diameters of the burner cap 21 and the burner head 20b. When the pot bottom temperature sensor 4 detects an abnormally high temperature on the bottom of the cooking vessel P, it will be described later. Burner 2 by means
Is extinguished to prevent overheating of the cooking vessel P. The pan bottom temperature sensor 4 is provided at an upper end portion of a support rod 6 fixed to a container of the stove via a mounting bracket 5. The burner cap 21 is provided with a heat shield cylinder 21a that surrounds the pan bottom temperature sensor 4 to suppress the radiant heat from the flame of the burner 2 acting on the pan bottom temperature sensor 4.

The pan bottom temperature sensor 4 is, as shown in FIG.
A cylindrical casing 41 having a cap-shaped upper plate 40 attached to the head is provided. The casing 41 is externally vertically movably inserted into the upper end portion of the support rod 6 and includes a flange attached to the upper end of the support rod 6. A coil-shaped spring 42 is interposed between the spring receiver 60 and the upper plate 40. Thus, the pot bottom temperature sensor 4 is urged upward by the spring 42, and the upper plate 40 abuts against the bottom surface of the cooking vessel P on the gotoku 3. The casing 41 is formed in a stepped shape having a lower small-diameter portion 41 a, so that when the upper end of the small-diameter portion 41 a contacts the spring receiver 60, the casing 41 does not further move upward.

The upper plate 40 is caulked to a casing 41, and a bimetal switch 43 as a heat-sensitive element is mounted on the back surface thereof. The bimetal switch 43 has a cylindrical bimetal case 43 with a closed head.
1, a disc-shaped bimetal 430 that contacts an annular bead 430a provided on the head and a switch 432 operated by the bimetal 430 are housed. The bimetal switch 43 is attached to the upper plate 40 by spot welding to the back surface of the upper plate 40. Then, the opening on the side opposite to the head of the bimetal case 431 is sealed with a cover member 433 and an inert gas is sealed therein to protect the bimetal 430 and the switch section 432.

The switch section 432 is connected to one terminal pin 4 of a pair of terminal pins 434 and 434 inserted in the lid member 433.
34 and a movable contact 432 made of a spring plate attached to the upper end of the other terminal pin 434.
The rod 435, which is in contact with the lower surface of the central part of the bimetal 430, is brought into contact with the movable contact piece 432b through the guide member 436 in the bimetal case 431.

The bimetal 430 is always in a downwardly convex curved state, and the movable contact piece 432b is pushed downward via the rod 435 to contact 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 to an upwardly convex state, and the movable contact piece 432 is raised.
b is separated from the fixed contact 432a by its own elastic restoring force, and the bimetal switch 43 is turned off.

Further, the casing 41 of the pan bottom temperature sensor 4
Inside, a thermal fuse 44 connected in series to the bimetal switch 43 is provided. In this case, the bracket 45 for the thermal fuse 44 can be attached to the back surface of the upper plate 40. In the present 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 has a pocket portion 4 in which the thermal fuse 44 can be stored from the side opposite to the upper plate 40.
5a, a bendable locking piece 45b for retaining the thermal fuse 44 with respect to the pocket 45a, and a fixing tongue piece 45c to be attached to the outer surface of the bimetal case 431. One side 45c is attached to the outer surface of the bimetal case 431 by spot welding.

When assembling the pan bottom temperature sensor 4, first, the bimetal case 431 is attached to the back surface of the upper plate 40.
Then, a guide member 436 in which a bimetal 430 and a rod 435 are assembled in a bimetal case 431 with the upper plate 40 turned upside down as shown in FIG. And the lid member 433 to which the switch section 432 is attached, in order to assemble the bimetal switch 43 and to mount the pocket section 4 of the bracket 45.
The thermal fuse 44 is housed in 5a, and the locking piece 45b is bent to prevent the thermal fuse 44 from coming off. Thus, by mounting the thermal fuse 44 to the bracket 45 after spot welding the bimetal case 431 to the upper plate 40, it is possible to prevent the thermal fuse 44 from being adversely affected during spot welding.

Next, one of the pair of terminal pins 434, 434 inserted into the cover member 433 is connected to one of the pair of fuse terminals 44a, 44a of the thermal fuse 44, and further,
The other terminal pin 434 is connected to one of the pair of lead wires 46, 46, and the other fuse terminal 44a is connected to the other lead wire 46.

Next, the lead wires 46, 46 are inserted into the hollow support rod 6 through the inner diameter of the spring 42 while the casing 41 is extrapolated to the support rod 6 and the spring 42 is mounted on the spring receiver 60. After the insertion, 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 periphery of the upper plate 40 is swaged to the upper end of the casing 41 with the spring 42 lightly compressed. Join. Thereby, the bimetal switch 43
And a temperature sensor 44 connected in series can be assembled.

Referring to FIG. 1, an electromagnetic safety valve 7, a main valve 8 opened and closed by a point fire extinguishing operation, and a flow control valve 9 are arranged in series in the gas supply path of the burner 2 from the upstream side. Have been. The electromagnetic safety valve 7 includes an electromagnet 7a connected to the thermocouple 10 facing the flame detecting combustion part of the burner 2, and the electromagnetic safety valve 7 is kept open by the electromotive force of the thermocouple 10. The thermocouple 10 is fixed to the mounting bracket 5 that is common to the support rod 6.

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 thermocouple 10 are connected.
Are connected to a pair of terminals of the electromagnet 7a, respectively. Thus, a series connection circuit of the bimetal switch 43 and the thermal fuse 44 intervenes in series with the thermocouple 10 in the safety valve circuit connecting the thermocouple 10 and the electromagnetic safety valve 7.

In such a circuit, when the cooking vessel P becomes abnormally high in temperature, the bimetal switch 43 is turned off and the electromotive force of the thermocouple 10 is not input to the electromagnetic safety valve 7, and the supply of gas is shut off by closing the electromagnetic safety valve 7. Then, the burner 2 is extinguished.

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 blowing of the temperature fuse 44. When the electromagnetic safety valve 7 is closed, the fire of the burner 2 is surely extinguished.

In this case, the temperature at which the thermal fuse 44 is blown is set to a temperature slightly higher than the temperature at which the bimetal switch 43 is turned off (for example, 270 ° C.) so that the thermal fuse 44 is blown only when the bimetal switch 43 is turned on. ).

[0027]

As is apparent from the above description, according to the present invention, since a bimetal switch is used as a thermal element of the pan bottom temperature sensor, a controller is not required, the cost is low, and the ON failure of the bimetal switch is prevented. Even if it occurs, the burner can be surely extinguished by blowing the thermal fuse and reliability can be ensured.

[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-away side view of an example of the pot bottom temperature sensor of the present invention.

FIG. 3 is a perspective view showing an assembled state of the pan bottom temperature sensor of FIG. 2;

[Explanation of symbols]

P pan (cooking container) 2 burner 4 pan bottom temperature sensor 40 top plate 41 casing 43 bimetal switch (thermal element) 430 bimetal 431 bimetal case 432 switch section 44 temperature fuse 45 bracket 7 electromagnetic safety valve 10 thermocouple

Claims (3)

[Claims] 1. A pot bottom temperature sensor for detecting a temperature of a cooking vessel, the casing being in contact with a bottom face of the cooking vessel;
With a thermosensitive element provided in the casing, the thermosensitive element is configured by a bimetal switch,
A pot bottom temperature sensor, wherein a temperature fuse connected in series to a bimetal switch is provided in a casing. 2. A bimetal switch comprising a bimetal, a switch portion operated by the bimetal, and a bimetal case accommodating the bimetal and the switch portion, and a bracket holding the thermal fuse on an outer surface of the bimetal case. At the same time, the head of the bimetal case is welded to the back of the upper plate constituting the head of the casing, the bracket is welded to the upper plate, and then the thermal fuse is mounted to the bracket. The pan bottom temperature sensor according to claim 1, wherein: 3. A gas stove provided with the pan bottom temperature sensor according to claim 1 or 2, which is provided in a thermocouple for detecting a flame of a burner for heating a cooking vessel, and in a gas supply path to the burner. A gas characterized in that a series connection circuit of the bimetal switch and the thermal fuse is interposed in series with a thermocouple in a safety valve circuit for connecting an electromagnetic safety valve held in an open state by an electromotive force of a thermocouple. Cook.