JP3320377B2 - Pressure 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 pressure cooker, and more particularly to a pressure cooker characterized by a relief valve structure.

[0002]

2. Description of the Related Art Conventionally, in a pressure cooker such as a pressure cooker,
Pressure cooking can be performed while maintaining the internal pressure at a set pressure exceeding 1 atm.

In order to maintain the internal pressure at a set pressure, heating is controlled by using a pressure regulating ball or directly detecting the temperature and internal pressure of generated steam.

In the case of using a pressure adjusting ball, a pressure adjusting hole provided in a lid is closed with the pressure adjusting ball so that the pressure adjusting ball is prevented from moving unless the internal pressure exceeds a set pressure exceeding 1 atm. ing.

On the other hand, in the apparatus for directly detecting the temperature and internal pressure of water vapor, the temperature and internal pressure of water vapor generated by a temperature sensor and a pressure sensor provided on a cover are directly detected, and heating is controlled based on the detection result. ing.

[0006]

However, in the case of using a pressure regulating ball, since the heating is controlled based on the detection result of the inner pot temperature which is not directly related to the internal pressure, the internal pressure may exceed the set pressure. is there. In this case, since the steam generated by floating the pressure regulating ball is discharged to the outside, there is a problem that an installation place of the cooker is restricted.

On the other hand, for detecting the temperature of water vapor or the like,
Since the temperature of the portion where the internal pressure acts directly or the internal pressure itself can be detected, the heating can be controlled so that the internal pressure does not exceed the set pressure. However, in case the internal pressure exceeds the set pressure, a configuration that can communicate between the inside and outside is required separately. For this reason, there are problems such as an increase in the number of parts and an increase in the number of assembly work steps.

[0008] Therefore, an object of the present invention is to provide a pressure cooker having a simple configuration and capable of suppressing discharge of steam.

[0009]

According to the present invention, as a means for solving the above problems, an exhaust passage formed in a lid is opened and closed by a relief valve so that an internal pressure exceeds a set pressure exceeding 1 atm. In a pressure cooker that communicates between the inside and outside of the cooker so that the valve body of the relief valve is integrated with temperature detection means, the internal pressure is maintained at the set pressure based on the temperature detected by the temperature detection means. Control means for controlling heating so as to perform heating.

With this configuration, not only can the temperature be detected at a position facing the internal space where the internal pressure can be accurately estimated, but also if the internal pressure exceeds the set pressure, the relief valve operates. It is possible to communicate between inside and outside.

[0011] When the temperature detecting means is composed of a thermistor and a cap which covers the thermistor and is exposed to the internal space of the cooker and is made of a material having high thermal conductivity suitable for temperature detection by the thermistor, This is preferable because it can prevent direct exposure to water vapor.

The lower surface of the lid is formed of a heat radiating plate, and an inner lid is detachably provided on the heat radiating plate, and the relief valve is slidably inserted into a case attached to the heat radiating plate. The configuration in which the temperature sensor is housed and sealed with packing is preferable because the inner lid can be removed even when the temperature detecting means is provided in the relief valve.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic view of a pressure cooker as an example of a pressure cooker, and FIG. 2 is a partial sectional view thereof. In this pressure cooker, a relief valve 4 is provided on a lid 3 that closes an inner pot 2 housed in the rice cooker body 1.

The lid 3 comprises an upper lid plate 5 and a lower lid plate 6. A housing recess 7 is formed on the outer peripheral portion of the lid lower plate 6 so as to protrude upward. On the lower surface of the lid lower plate 6, a radiator plate 8 having a heater 30 is screwed. An opening 9 is formed in the heat sink 8 at a position corresponding to the accommodation recess 7. Further, an inner lid 10 is attached to a lower surface of the heat sink 8. In the inner lid 10,
A recess 11 swelling downward is formed at a position corresponding to the accommodation recess 7 and the opening 9, and an exhaust hole 12 is formed at the center of the bottom surface. Further, the gap between the heat radiating plate 8 and the inner lid 10 allows the exhaust passage 1 to communicate with the outside.
3 are formed.

The relief valve 4 has a structure in which a valve body 15 in which a thermistor 28 as a temperature detecting means is integrated is slidably housed in a case 14 and sealed by a packing 16.

The case 14 is a stepped cylinder having a small diameter portion 17 and a large diameter portion 18. A center hole 17 a is formed in the ceiling surface of the small diameter portion 17, and a cylindrical contact portion 17 b protrudes toward the opening side of the large diameter portion 18 at the inner edge of the connection portion with the large diameter portion 18. The opening edge of the large-diameter portion 18 is mounted on the upper peripheral edge of the opening 9 of the heat sink 8.

The valve element 15 is composed of a cylindrical sliding part 19 and a valve part 20 mounted on the lower end thereof. The cylindrical sliding portion 19 penetrates the center hole 17a of the case 14, and has a flange 21 formed at the upper end. The cylindrical sliding portion 19
Is provided with a spring 23, which urges the valve body 15 downward.

The valve section 20 comprises a cylindrical section 24 and a temperature detecting section 25 fitted and integrated at the center thereof. Tubular part 24
An engagement receiving portion 26 is formed on the outer periphery of the pair by a pair of annular grooves. The distal end portion of the cylindrical portion 24 has a small outer diameter and is formed to have a size that closes the exhaust hole 12 of the inner lid 10. The temperature detecting section 25 includes a cap section 27 made of a material having high thermal conductivity such as an aluminum alloy, and a thermistor 28 housed in the cap section 27. The temperature detected by the thermistor 28 is input to the control device 29, and based on the detected temperature, the control device 29 controls the energization of the heater 30 in the pressure cooking process as described later.

The packing 16 includes a cylindrical portion 31 and an annular flange portion 33.
It consists of On the inner surface of the cylindrical portion 31, the valve portion 20 is provided.
An engagement groove 32 that engages with the engagement receiving portion 26 is formed. In addition, the annular flange portion 33 includes a curved portion 34 that is elastically deformed as the valve body 15 described later moves. The outer edge of the annular flange 33 is attached to the opening edge of the large diameter portion 18 of the case 14.

In the pressure cooker having the above-described structure, it is only necessary to attach the pre-assembled relief valve 4 to the heat radiating plate 8. It can be easily assembled without increasing. In the assembled state, the valve body 15 is urged downward by the spring 23, and the cylindrical portion 24 of the valve portion 20 is recessed 11 so that the packing 1 is attached to the upper peripheral edge of the exhaust hole 12.
6 to seal the exhaust hole 12. When a pressure exceeding the upper limit value (1.25 atm) of the set pressure acts, the valve body 15 moves mainly against the urging force of the spring 23, and the internal pressure is radiated by opening the exhaust hole 12. The air is released to the atmosphere through an exhaust passage 13 between the plate 8 and the inner lid 10.

Next, the operation of the pressure cooker provided with the relief valve 4 will be described.

In this pressure rice cooker, rice cooking is controlled through the steps of preheating, steam treatment, pressure rice cooking and steaming, as in the prior art. In the pressure cooking step, heating control is performed so that the internal pressure becomes a set pressure exceeding 1 atm (here, 1.2 to 1.25 atm). In this heating control, the internal pressure is estimated according to the saturated steam curve based on the temperature detected by the thermistor 28 provided in the relief valve 4. Then, duty control is performed on the power supplied to the heater 30 based on the estimation result. Since the thermistor 28 is integrated with the cap portion 27 of the relief valve 4 that is directly exposed to the internal space of the rice cooker main body 1, it is possible to detect an accurate temperature according to a difference in internal pressure. Therefore, by performing the heating control based on the detected temperature, it is possible to perform pressure cooking while maintaining the internal pressure accurately at the set pressure. If the internal pressure exceeds the set pressure, the valve body 15 of the relief valve 4 moves mainly against the urging force of the spring 23 to open the exhaust hole 12 and release to the atmosphere. I do.

In addition, with the above-described configuration of the relief valve, the inner lid 10 can be detachably attached to the heat sink 8. That is, the relief valve slidably accommodates the valve body 15 in which the thermistor 28 is integrated in the case 14,
The structure is sealed with packing 16. For this reason, the lead wire of the thermistor 28 can be wired in the cover 3 in advance, and no trouble occurs even if the inner cover 10 is removed. Therefore, the inner lid 10 can be washed in a circle and the heat radiating plate 8 can be cleaned, so that a configuration excellent in hygiene can be achieved.

[0025]

As is apparent from the above description, according to the pressure cooker according to the present invention, since the temperature detecting means is integrated with the valve body, the detected temperature can be reduced without increasing the number of parts. Based on this, it is possible to accurately maintain the internal pressure at a set pressure exceeding 1 atm, thereby reliably suppressing the discharge of steam.

Further, since the temperature detecting means is configured to cover the thermistor with a cap made of a material having a high thermal conductivity, it is possible to detect a good temperature while extending the life of the thermistor.

Further, since the relief valve is attached to the heat radiating plate, even if the relief valve is provided with a temperature detecting means, the inner lid can be removed and the whole can be washed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a pressure cooker according to the present embodiment.

FIG. 2 is an enlarged sectional view of a portion where the relief valve of FIG. 1 is mounted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Rice cooker main body 2 ... Inner pot 3 ... Lid 4 ... Relief valve 10 ... Inner lid 12 ... Exhaust hole 13 ... Exhaust flow path 14 ... Case 15 ... Valve body 16 ... Packing 20 ... Valve part 25 ... Temperature detection part 27 ... Cap part 28 ... Thermistor (temperature detecting means) 29 ... Control device 30 ... Heating heater

Claims (2)

(57) [Claims] 1. A pressure cooker that opens and closes an exhaust passage formed in a lid with a relief valve and communicates between the inside and outside of the cooker so that the internal pressure does not exceed a set pressure exceeding 1 atm. While integrating the temperature detecting means into the valve body, a control means for controlling heating so as to maintain the internal pressure at the set pressure based on the temperature detected by the temperature detecting means is provided, and the temperature detecting means comprises a thermistor and A pressure cooker which covers the thermistor, is exposed to the interior space of the cooker, and is made of a material having high thermal conductivity suitable for temperature detection by the thermistor. 2. The lower surface of the lid is formed of a radiator plate, and an inner lid is detachably provided on the radiator plate, while the relief valve is slid in a case attached to the radiator plate. The pressure cooker according to claim 1, wherein the pressure cooker is freely housed and sealed with a packing.