JPS623049Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a pressure cooker having a structure in which cooking is performed by bringing the bottom of the pot into contact with a heating plate.

Conventionally, the bottom of the pot of this type of pressure cooker is usually formed into a spherical convex surface in order to ensure strength against the increase in internal pressure. The whole part is in close contact with the heating plate. However, when the internal pressure of the pot rises due to the start of cooking, the bottom of the pot undergoes slight deformation, as if expanding due to the internal pressure.
Contact with the hot plate becomes local contact at the center,
There was a problem in that the area around it rose slightly, and as a result, the contact area with the heating plate decreased, resulting in poor heating efficiency.

Therefore, an object of the present invention is to provide a pressure cooker that can prevent the contact area with the heating plate from decreasing as much as possible and improve heating efficiency even when the bottom of the pot is deformed due to an increase in internal pressure. be.

An embodiment of the present invention will be described below based on the drawings. First, in Figure 1 showing the overall configuration, 1 is the outer frame of the pressure cooker, 2 is the inner frame, 3 is the heating plate disposed at the bottom of the inner frame 2, and 4 is a plate that can be inserted into and taken out of the inner frame 2. A pot is housed and placed on a heating plate 3, a lid 5 is airtightly attached to the top of the pot 4 by a bayonet engagement mechanism, etc., and a pressure regulating valve 6. The pot 4 has a bottom 4a formed into a spherical convex surface to ensure strength against an increase in internal pressure. On the other hand, the heating plate 3 is made of aluminum die-casting, and has an annular electric heater 7 mounted on the lower surface near the outer periphery, and has a heat transfer surface in contact with the bottom 4a of the pot 4 on the annular region near the outer periphery of the upper surface. 3a, and a circular recess 8 corresponding to a relief part is formed in the center surrounded by the heat transfer surface 3a. The heat transfer surface 3a is formed by aluminum die casting and then finished into a spherical concave surface so as to match the bottom 4a of the pot 4. While forming the surface 3a as an inclined surface descending toward the recess 8,
The recess 8, which is a non-contact area with the bottom 4a of the pot 4, does not require finishing, so it is left as a die-cast base. Reference numeral 9 denotes a heat-sensitive part of a thermal switch for controlling power on/off of the electric heater 7, which protrudes through a hole 10 in the center of the heating plate 3 so as to come into contact with the center of the bottom 4a of the pot 4.

Next, the operation of the above configuration will be explained. When the electric heater 7 is energized to perform cooking, the heating plate 3 is heated, and the heat is transmitted to the pot 4 via the heat transfer surface 3a. As a result, the water in the pot 4 is heated and boiled, and the internal pressure of the pot 4 increases due to the generated steam. Then, the bottom portion 4a of the pot 4 receives the internal pressure and deforms so as to bulge downward and increase its curvature, as shown by the two-dot chain line in FIG. by the way,
Different from this embodiment, for example, if the heat transfer surface of the heating plate is formed flat, and therefore the bottom of the pot is formed flat, the amount of downward bulging deformation of the bottom of the pot will be different from that of this embodiment. It becomes larger in comparison. One of the reasons for this is that the strength of the bottom of the pot against increases in internal pressure is inferior to that of this embodiment, and another reason is that if the amount of increase in internal volume of the pot due to the bulging deformation of the bottom of the pot is different from that of this embodiment. Even if they are the same, a pot with a flat bottom has a smaller area than a convex pot like the one in this example, so the amount of downward bulge deformation of the bottom of the pot is correspondingly large. It is about becoming.

Taking the above points into consideration, in this embodiment, the heat transfer surface 3a of the heating plate 3 is formed into an inclined surface that descends toward the recess 8, and the bottom 4a of the pot 4 is formed into a convex surface accordingly. Therefore, as the internal pressure of the pot 4 increases, the bottom 4a of the pot 4
The amount of downward bulging deformation has become relatively small. Moreover, the amount of deformation of the bottom portion 4a at this time is larger towards the center and smaller towards the outer periphery connected to the peripheral wall 4b, but the relatively large deformation on the center side is released by expanding into the recess 8 of the hot platen 3. Therefore, it is possible to prevent the outer peripheral side portion of the bottom portion 4a from completely lifting off from the heat transfer surface 3a, and maintain a good contact state with the heat transfer surface 3a. Therefore, compared to the conventional method in which heating was performed with only the center part of the bottom of the pot in local contact with the heating platen, in this embodiment, a wide annular area near the outer periphery contacts the heating platen 3. The heat transfer area becomes larger and heating efficiency improves. Furthermore, heat can be efficiently conducted to the pot 4 also in relation to the mounting position of the electric heater 7. In addition, in conventional methods, the entire bottom of the pot is in contact with the heating plate at the beginning of heating, but this state is maintained for a short time compared to the total cooking time, so this embodiment has better heating efficiency. Much better in that respect.

As is clear from the above description, the present invention forms a relief part in the center of the heating plate against the swelling deformation of the bottom of the pot, and also directs the part of the heating plate that contacts the bottom of the pot toward the relief part. Since the surface is formed with a descending slope, it is possible to reduce the amount of bulging deformation of the bottom of the pot due to an increase in the internal pressure of the pot during cooking, and to allow the bulging deformation of the bottom of the pot to escape through the relief part. This has the practical effect of preventing a reduction in the contact area with the heating plate due to lifting of the pot to the utmost, and transmitting heat to a wide area near the outer periphery of the bottom of the pot, improving heating efficiency.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the whole, FIG. 2 is a perspective view of the heating plate, and FIG. 3 is a longitudinal sectional view of the main parts for explaining the operation. In the figure, 3 is a heating plate, 4 is a pot, and 8 is a recess (relief part)
It is.

Claims (1)

[Scope of utility model registration request] In a device in which cooking is performed by bringing the bottom of a pot into contact with a heating plate, a relief portion is formed in the center of the heating plate to prevent expansion and deformation of the bottom of the pot due to an increase in the internal pressure of the pot, and A pressure cooker characterized in that a portion that contacts the bottom portion is formed as an inclined surface that descends toward the relief portion.