JP2584699Y2 - Mounting structure of thermal fuse in electric cooker - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal fuse mounting structure for preventing overheating in an electric cooker such as a fryer for frying oil.

[0002]

2. Description of the Related Art In general, a fryer heats oil contained in an inner container by an electric heater provided at the bottom of the inner container to fry food.

The temperature of oil is usually adjusted to a predetermined temperature by an automatic temperature controller. However, if the temperature of the oil rises abnormally due to a failure of the automatic temperature controller, it is possible that the worst fire may occur, which is extremely dangerous. Therefore, a temperature fuse for detecting an abnormal temperature rise and cutting off the circuit is provided.

[0004] Normally, a temperature fuse of an electric cooker is mounted on or near a heat shield plate below the bottom of the inner container to measure the ambient temperature around the electric heater, but a fryer measures the temperature of oil in the inner container. It is necessary to accurately detect the temperature and shut off the circuit when the oil temperature rises abnormally, so the applicant wound a metal holder around the temperature fuse and brought the holder into direct contact with the inner container. The oil temperature is easily transmitted to the thermal fuse.

[0005]

[Problem to be solved by the invention] In this structure,
The oil temperature passes through the inner wall of the inner container and is transmitted to the thermal fuse via the holder.In addition to the heat transfer path, the heat of the electric heater attached to the inner container is
Some elements travel down the wall of the inner vessel without heating the oil and are transmitted to the thermal fuse.

Accordingly, particularly when the mounting position of the thermal fuse is close to the electric heater, there is a possibility that the thermal fuse is overheated and unnecessarily blown off even though the oil is not so much heated.

FIG. 6 is a graph showing the relationship between the temperature change of the oil and the temperature change of the thermal fuse in the conventional structure. Graph A shows the temperature of the oil, graph B shows the temperature of the thermal fuse, and graph C shows the temperature. Indicates whether power is supplied to the electric heater. In this graph, the temperature fuse is 169 °
What was melted by using was used.

[0008] Then, energization is started at O, and when the oil temperature reaches about 185 ° C, the thermostat operates,
Repeat connection to the electric heater.

Here, the oil is repeatedly heated and cooled by an electric heater, and its temperature graph A changes in a sawtooth shape within a range of about 180 to 195 ° C.

Accordingly, the temperature fuse also changes substantially in accordance with the oil temperature change, and the temperature graph B of the temperature fuse changes in a saw-tooth shape in the range of 135 to 145 ° C. almost in parallel with the graph A. doing.

Here, at the time point D, the object to be cooked was put into the oil, and cooking of the fried food was started. The oil temperature is lowered by charging the food, and the oil temperature is increased by the electric heater. Accordingly, as shown in the graph C, the energizing interval to the electric heater is shortened, and the energizing time is increased. .

The oil temperature is complicatedly related to the temperature drop due to the introduction of the food and the heating by the electric heater, and the oil temperature graph A is frequently and irregularly within the range of about 160 to 180 ° C. A vertical waveform is formed.

On the other hand, the temperature graph B of the temperature fuse is linked to the vertical waveform of the oil temperature graph A, but is affected by the electric heater which is frequently energized. Despite the temperature drop, the temperature of the thermal fuse has risen, reaching the range of about 150-160 ° C.

As is clear from graph B, the thermal fuse temporarily exceeds 160 ° C. and approaches the melting temperature of 169 ° C., and if the conditions are poor, the thermal fuse can be used even in a normal use condition. There is a possibility of melting.

However, if a temperature fuse having a higher melting temperature is used or a mounting structure that is less sensitive to heat is employed, the oil does not melt properly when the oil temperature rises abnormally, and the oil ignites. There is a risk.

The present invention has been made in view of the above circumstances, and it is possible to appropriately sense the temperature of oil and appropriately melt the oil when an abnormal temperature rise occurs. An object of the present invention is to provide a structure for mounting a thermal fuse, which does not unnecessarily melt under the influence of a heater.

[0017]

According to the present invention, there is provided a structure in which a metal holder is wound around a thermal fuse, the holder is brought into direct contact with an inner container of an electric cooker, and the temperature of the content is detected by the thermal fuse. In the thermal fuse, a central portion of the thermal fuse is in close contact with the holder directly or via an insulating tube fitted outside the thermal fuse, and at both ends of the thermal fuse, the holder and the thermal fuse are provided. Alternatively, an interval is formed between the insulating tube and the insulating tube.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. The drawings show an embodiment of a fryer 1 as an electric cooker to which the present invention is applied, and an inner container 3 is housed inside an outer package 2.

The exterior body 2 comprises a cylindrical outer body 4 formed by bending a metal plate, and a bottom body 5 provided below the outer body 4, and a handle 6 is provided on the outer body 4. .

The inner container 3 is a cylindrical container having a bottom made of stainless steel, and is engaged with the outer shell 4 at the upper end of the peripheral wall 7. A concave portion 10 is formed in the bottom surface 8 of the inner container 3, and a surface heater 9 is attached to a lower surface of the concave portion 10. Further, a part of the concave portion 10 extends laterally from the peripheral edge of the surface heater 9 to form an extended concave portion 11 flush with the concave portion 10. 12 is the surface heater 9
Is a heat shield plate provided below.

Reference numeral 13 denotes a thermal fuse, on which an insulating tube 14 is fitted and held by a metal holder 15 from the outside of the insulating tube 14, and the holder 15 is attached to the heat shield plate 12. ing.

In the present invention, the holder 15 is used.
Is divided into three pieces, and a center piece 16 is wound around the center of the thermal fuse 13 from the outside of the insulating tube 14, and is firmly fastened and held.

Then, both end pieces 17, 17 of the holder 15 are provided.
Are loosely wound outside the insulating tube 14 at the positions of both ends of the thermal fuse 13,
The gaps 18 are formed between the first and second surfaces.

The distal end of the holder 15 is in direct contact with the lower surface of the extension recess 11 of the inner container 3, and the temperature of the extension recess 11 is transmitted to the tip of the holder 15, and the temperature is transmitted to the insulating tube 14. The temperature fuse 13 senses the temperature of the extension recess 11 via the temperature fuse 13.

A thermostat (not shown) is attached to the inner container 3 at an appropriate position to control the energization of the surface heater 9 according to the temperature of the inner container 3 to keep the temperature of the oil 19 in the inner container 3 constant. To be held.

In the present invention, the recess 10 and the extension recess 11 are not necessarily required as the structure of the inner container 3,
The bottom surface 8 may be flat. Further, the electric heater is not limited to the surface heater 9 but may use a sheathed heater.

Since the thermal fuse 13 is directly energized, the holder 1 is connected via the insulating tube 14.
5, but it is also possible to mount the thermal fuse 13 directly to the holder 15 if other suitable insulation measures are taken.

[0028]

According to the present invention, the oil 19 is put into the inner container 3, the surface heater 9 is energized to heat the oil 19, and the food is put in there to cook fried foods such as tempura and fries. be able to.

The temperature of the oil 19 is maintained at a predetermined temperature by the thermostat (not shown).

Further, when the automatic temperature control device fails and the surface heater 9 is kept energized, the oil 19 is overheated. When the oil 19 reaches a predetermined temperature, the oil 19 is heated. The fuse 13 detects and cuts off the power supply to the surface heater 9 to prevent the oil 19 from being overheated and ignited.

In the present invention, since only the center piece 16 of the holder 15 is wound around the center of the thermal fuse 13, heat is transferred from the inner container 3 to the thermal fuse 13 via the holder 15. It is late.

Therefore, the temperature fuse 13 does not follow the frequent temperature change of the inner container 3 due to the energization of the surface heater 9, so that the temperature fuse 13 does not unnecessarily rise in normal use.

This state is shown in the graph of FIG.
In the state where the objects to be cooked from O to D in the graph of FIG. 5 are not charged, the heating and the cooling by energizing the surface heater 9 are repeated, and the temperature graph A of the oil 19 and the temperature graph B of the temperature fuse 13 become: 6 shows a sawtooth-like temperature change similar to that of the conventional example shown in FIG.

When the object to be cooked is put into the inner container 3 at the time point D and the cooking is started, the temperature of the oil 19 drops, and in order to compensate for this, the energizing interval to the surface heater 9 is short and the energizing time is short. The time gets longer.

The oil temperature graph A shows frequent and irregular temperature changes in the range of about 160 to 180 ° C. as in the case of FIG.

On the other hand, the thermal fuse 13 shown in FIG.
Although the temperature graph B of FIG. 2 draws a waveform almost interlocked with the oil temperature graph A, the temperature range is about 140 to 150.
It is in the range of ° C. and hardly changes from before the time point D.

If the oil 19 is abnormally heated,
The heat is transmitted to the central portion of the thermal fuse 13 via the central piece 16 of the holder 15 and the thermal fuse 13
Can be reliably transmitted to the thermal fuse 13 with a slight time lag, and the thermal fuse 13 can be melted to cut off the circuit, with a slight time delay. It is.

[0038]

[Effect of the Invention] Therefore, according to the present invention, the thermal fuse 1
3 does not follow a rapid change in temperature, so that the temperature fuse 13 is kept in a substantially constant temperature range in a normal use state of the fryer 1, and the temperature fuse 13 becomes unnecessary.
Is not cut off.

As is clear from FIG. 5, the smooth temperature change of the oil 19 is reliably transmitted to the thermal fuse 13, so that the thermostat malfunctions and the surface heater 9 is kept energized. If the temperature of the oil 19 rises abnormally, the thermal fuse 13 reliably detects the change in temperature, cuts off the circuit, cuts off the circuit, and prevents the oil 19 from firing.

Therefore, according to the present invention, the temperature fuse 13 does not melt in a normal use condition, and can be used normally. In addition, when the temperature of the oil 19 rises abnormally, it is detected without fail. Temperature fuse 13
Melts and is safe and secure.

In the above description, the fryer 1 has been described as an electric cooker to which the present invention is applied. 13 can also be widely used.

[Brief description of the drawings]

FIG. 1 is a central longitudinal sectional view showing an embodiment of a fryer 1 to which the present invention is applied.

FIG. 2 is a bottom view of the inner container 3 in the fryer 1.

FIG. 3 is a perspective view showing a mounting structure of the thermal fuse 13 according to the present invention.

FIG. 4 is a central longitudinal sectional view showing a mounting structure of the thermal fuse 13 of the present invention.

FIG. 5: Oil 1 in fryer 1 to which the present invention is applied
9 is a graph showing the temperature change of the thermal fuse 13

FIG. 6 is a graph showing a temperature change of oil 19 and thermal fuse 13 in fryer 1 having a thermal fuse attached in a conventional structure.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 fryer (electric cooker) 3 inner container 9 surface heater (electric heater) 13 thermal fuse 14 insulating tube 15 holder 16 center piece 17 both ends piece 18 interval 19 oil (content)

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tsutomu Ihara 1-20-5 Tenma, Kita-ku, Osaka-shi, Osaka Zojirushi Mahobin Co., Ltd. (72) Inventor Takayuki Sano 1-20, Tenma, Kita-ku, Osaka-shi, Osaka No. 5 Inside Zojirushi Mahobin Co., Ltd. (72) The inventor Akira Maenaka 1-20-5 Temma, Kita-ku, Osaka City, Osaka Prefecture Inside Zojirushi Mahobin Co., Ltd. (56) References JP-A-60-31717 (JP, A) 60-179237 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) A47J 37/12

Claims (1)

(57) [Scope of request for utility model registration] 1. A metal holder (15) is wound around a thermal fuse (13), and the holder (15) is brought into direct contact with an inner container (3) of an electric cooker (1), so that the thermal fuse (13) is heated. In the structure for detecting the temperature of the contents (19), the center portion of the thermal fuse (13) is fitted to the holder (15) either directly or outside the thermal fuse (13). At the same time, a gap (18) is formed between the holder (15) and the thermal fuse (13) or the insulating tube (14) at both ends of the thermal fuse (13). Mounting structure of a thermal fuse in an electric cooker, characterized in that: