JPS5836359Y2 - pressure cooker - Google Patents

Description

[Detailed explanation of the invention] This invention detects the temperature of the pot and controls the temperature inside the pot, thereby keeping the pressure inside the pot lower than the operating pressure of the valve, and creating an airtight state to prevent steam from coming out from inside the pot during normal use. The present invention relates to a pressure cooker that performs cooking by heating.

6 Below, the embodiments of the present invention shown in the drawings will be described in detail.

FIG. 1 is a longitudinal cross-sectional view showing the structure of the cooking device according to the present invention, and FIG. 2 is an electric circuit diagram thereof, with the cross-sectional position being changed from the broken line in FIG.

First, in FIG. 1, 1 is a main body equipped with a handle 2 and an operation panel part 3 on the outer circumferential side, 4 is a hot plate with a main heater 5 and an auxiliary heater 6 buried therein, and is arranged on the inner bottom surface of the main body 1; 8 is a pot that can be inserted into and removed from the main body 1; 9 is a heat-sensitive element that passes through the center of the hot plate 4 and comes into elastic contact with the bottom of the pot 8; 10 is an upper part of the pot 8. A lid 12 that airtightly closes the opening via the backing 11 is provided on the lid 10;
A pressure regulating valve 13 is also provided on the lid 10, and opens to reduce the pressure inside the pot 8 when the pressure reaches a level higher than the normal operating pressure.If the pressure regulating valve 12 is inoperable, the internal pressure of the pot 8 increases abnormally. This is a safety valve that opens when an explosion occurs to prevent an explosion.

A pressure mechanism 14 is provided between the pot 8 and the lid 10, which pressurizes the lid 10 by applying pressure to maintain the closed state of the lid 10, and enables the lid 10 to be opened by releasing the pressure. It is being

This pressure mechanism 14 is fixed to the outer peripheral surface of the pot 8, and is supported by a pair of locking metal fittings 15 that protrude upward and diverge from each other, and a screw mechanism 16 in the center of the lid 10, and is engaged. The pressurizing arm 17 has both ends engaged with and disengaged from the stopper 15.

The screwing mechanism 16 is configured to operate to move the pressure arm 17 and the lid 10 toward or away from each other by rotating the eldest child 16'.

That is, when the locking metal fitting 15 and the pressure arm 17 are in a locked state, when the screw mechanism 16 is operated to separate the pressure arm 17 and the lid 12, the pressure arm 17 is moved to the locking metal fitting 1.
Since the lid 10 is prevented from floating by the lid 5, the lid 10 is pressurized and the upper opening of the pot 8 is hermetically closed via the backing 11.

18 is a stopper that prevents the pressurizing arm 17 from rotating as the spring mechanism 16 is operated.

Incidentally, reference numeral 19 in FIG. 1 indicates a timer disposed on the operation panel section 3.

Next, the electric circuit shown in FIG. 2 will be explained.

The hot plate 4 is connected to a power supply terminal via a thyristor 20 such as a triac and a timer 19 in series, and a gate circuit of the thyristor 20 is formed by the heat sensitive element 9 and a resistor 21.

Such a control circuit controls the hot plate 4, that is, the heater 5.6, so that the internal pressure of the pot 8 is slightly lower than the operating pressure of the pressure regulating valve 12.

Therefore, in the present invention, as the heat-sensitive element 9, a material that is paramagnetic (
The present invention is characterized in that it uses a heat-sensitive element consisting of a magnetic material 9a (which loses its magnetism), a coil 9b wound around it, and a heat-sensitive case 9C housing them.

Hereinafter, the action of this heat-sensitive element 9 will be explained according to the waveforms of each part shown in the fourth figure and the temperature vs. B-H characteristics of the magnetic material 9a shown in the fifth figure.

The heat-sensitive element 9 is made of magnetic material 9 by the current flowing in it at room temperature.
A magnetic flux φ having the same phase as the power supply voltage e is generated at a, and at this time, the magnetic flux waveform exhibits saturation in a weak magnetic field because the magnetic material 9a has a rectangular hysteresis characteristic with a small coercive force. A symmetrical rectangular pulse that shows a sudden change when the voltage is applied is generated, and a symmetrical sharp pulse voltage ep is induced at both terminals of the heat-sensitive element 9 when the power supply voltage e is zero voltage.
By applying this pulse as a trigger to the gate of the thyristor 20, the thyristor 20 is rendered conductive.

As the temperature rises, the heat-sensitive element 9 reduces the pulse voltage ep by changing the hysteresis characteristic of the magnetic material 9a as shown in FIG. The voltage becomes lower than the trigger voltage, and the thyristor 20 becomes non-conductive.

Although it is possible to use a thermistor as the heat-sensitive element 9, a thermistor has a small heat capacity and is not suitable for a pressure cooker that performs cooking at a higher temperature than a normal cooker.

That is, since the thermistor has a small heat container, if it is placed in the center of the hot plate 4, it will be greatly affected by the radiant heat from the hot plate 4, and the pot 8
There is a concern that the pot 8 may not be able to accurately sense the temperature inside the pan 8 because it operates quickly due to the radiant heat from the hot plate 4 before the inside temperature reaches the set temperature.

In addition, in order to solve this problem, the pot 8 separated from the hot plate 4
It is also possible to provide a thermistor to sense the side temperature of the hot plate 4, but this has the disadvantage that it cannot be controlled by temperature changes at the center of the bottom of the hot plate 8, where the internal temperature of the hot plate 8 can be sensed most accurately. If it is unavoidable to arrange the thermistor, special measures such as covering the thermistor with a heat insulating material to increase the heat capacity will be required.

However, since the heat-sensitive element 9 made of the magnetic material 9a, coil 9b, etc. has a larger heat capacity than the thermistor, even if it is placed in the center of the hot plate 4, it will not be greatly affected by the radiant heat from the hot plate 4, and the pot 8 The internal temperature of the device can be sensed accurately through the center of its bottom surface.

To use the above-described pressure cooker, first place the pot 8 into the main body 1.
This can be done by inserting the lid into the pan, closing the top opening of the pot 8 with a lid 10 via the backing 11, and setting the timer 19 while pressing the lid 10 with the pressure mechanism 14.

By setting the timer 19, the heaters 5 and 6 are energized to heat the pot 8, the internal temperature of the pot 8 is controlled to the set temperature by the heat sensitive element 9, the thyristor 20, etc., and the internal pressure of the pot 8 is The pressure is maintained slightly lower than the operating pressure of the control valve 12, and cooking is performed in an airtight state without releasing steam from the pot 8.

As described above, according to the configuration of the present invention, the heat-sensitive element can accurately sense the internal temperature of the pot and control the heater without being greatly affected by radiant heat from the hot plate, making it extremely useful as a pressure cooker. It is.

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional view showing the configuration of the proposed cooking device, Figure 2 is its electric circuit diagram, Figure 3 is the constituent countries of the heat-sensitive element, Figure 4 a,
1) and c are waveform diagrams of the same parts, and FIG. 5 is a temperature versus BH characteristic diagram of the same magnetic material. 1: Main body, 4: Heat plate, 8: Pot, 9: Heat-sensitive element, 9a: Magnetic material, 9b: Coil, 9C: Heat-sensitive case, 10: Lid,
11: Backing, 20: Thyristor.

Claims (1)

[Scope of utility model registration request] A main body equipped with a hot plate with a heater embedded in the inner bottom, a pot that can be inserted into and removed from the main body and placed on the hot plate, and a lid that airtightly closes the iron pot via a backing, In a pressure cooker that performs cooking in an airtight state so that steam is not released from the inside of the pot during normal use, a thyristor is connected in series to the heater of the hot plate, and the gate I of the thyristor is connected in series to the heater of the hot plate.
- A heat-sensitive element consisting of a magnetic material that suddenly loses its magnetism at a certain temperature, a coil, and a heat-sensitive case that houses them is inserted into the circuit, and the thyristor is controlled by the presence or absence of a trigger pulse from the heat-sensitive element due to changes in the temperature of the pan. A pressure cooker characterized by controlling electricity supply to the heater.