JPH0336426A - Cooking device with pyroelectric type steam sensor - Google Patents

Abstract

PURPOSE:To present a lead from stretching and bending in the work of assembling and carrying in order, and prevent faults such as detachment of an element and an electrode from occurring by using a pyroelectric steam sensor and by fixing the lead to a part of the main body. CONSTITUTION:A pyroelectric steam sensor 1 has a heat-transferrable plate- shaped material 2 fixed to a guide 3 and a lead 4 adhesively attached to a part of the guide 3 by means of an adhesive agent 5. As a result, the lead 4 is restrained from moving and its adhesion point 6 to an electrode is freed from easy influences of stress. As to the actual flow of air, hot air (or steam) 8 passed through a hot air passage 7 mixes with cool air 10 passes through a cool air passage 9 to form a mixture-of-air 11, which flows out of a mixed air passage 12; as air thus mixes, the heat-transferrable plate-shaped material 2 of the pyroelectric steam sensor 1 is given a thermal change.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for installing a pyroelectric steam sensor for detecting high-temperature steam or hot air when used in a cooking appliance.

2. Description of the Related Art Conventional sensors of this type are often used for the purpose of detecting boiling in cooking appliances such as high-frequency heating devices, so here we will describe the technology related to high-frequency heating devices.

First, a typical example is an absolute humidity sensor.

The absolute humidity sensor in FIG. 8 includes a sensor chip 43 and a heater 4.
4, a resin base 45, a mesh cover 46, and a terminal 47. Since the resistance value of the sensor chip 43 changes depending on the humidity, the heater 44, which detects the cooking state by comparing the reference voltage with the voltage determined by the resistance value, uses an absolute humidity sensor in the high-frequency heating device. In this case, the sensor chip 43 is soiled by food gas, oil, etc., so it is used to refresh it, and the mesh cover 46 is used for wind protection and to save power for the heater 44.

(Nasinal Technical Report Vol. 29 N
3 JAN 1983) Fig. 9 shows a conventionally used high frequency heating device with an absolute humidity sensor. In the case of an absolute humidity sensor, since the moisture in the food boils and the humidity changes rapidly from decreasing to increasing, it is possible to determine the end of the tlI process by detecting this point. Based on this, as shown in FIG.
The device is controlled by detecting the voltage by dividing the voltage with the resistor 50. 19 is a magnetron. (For example, JP-A-53-77365) In addition to absolute humidity sensors, there are pyroelectric vapor sensors.

Generally, a pyroelectric vapor sensor has a structure as shown in FIG. 10, for example, in which a lead portion 4 is attached to a metal plate 2 and an electrode 14. (For example, Japanese Unexamined Patent Publication No. 62-37624) Problems to be Solved by the Invention However, when using a humidity sensor as described above, gas or oil in the food adheres to the humidity sensor during cooking, reducing detection sensitivity. Therefore, it is necessary to evaporate the deposits on the humidity sensor using a heater for refresh heat treatment or the like after each cooking cycle, resulting in the problem of extra power and cost.

There is also a method of using a pyroelectric vapor sensor instead of a humidity sensor, but since the lead part 4 is attached to the electrode 14, when the lead part 4 is pulled or bent, t
There was a problem with 8i14 peeling off from metal [2].

Therefore, an object of the present invention is to prevent the electrode from peeling off due to tension or bending of the lead.

Means for Solving the Problems In order to achieve the above object, the present invention uses an electroless steam sensor and has a structure in which the lead thereof is fixed to a part of the main body.

Function: The pyroelectric steam sensor-equipped cooker of the present invention fixes the lead to the main body. The base of the lead (i.e. the part where it attaches to the electrode)
Forces that place stress on (e.g. pulling or bending)
This prevents the occurrence of the pyroelectric steam sensor and prevents the pyroelectric steam sensor from being destroyed, resulting in a highly reliable cooking appliance with a sensor.

Example An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a configuration diagram when a pyroelectric steam sensor is fixed to a cooking appliance main body. The pyroelectric vapor sensor 1 has a heat conductive plate 2 fixed to a guide 3, and a lead 4 is bonded to a part of the guide 3 with an adhesive 5. For this reason, lead 4
movement is restricted, and the adhesive portion 6 with the electrode is placed in a state where stress is less likely to be applied. The actual flow of air is that the hot air (or steam) 8 passing through the hot air path 7 is mixed with the cold air 10 passing through the cold air path 9, and is then transferred to the heat conductive plate 2 of the pyroelectric steam sensor 1. It undergoes a thermal change, becomes mixed air 11, and exits mixed air path 12.

FIG. 2 shows a top view (a) of the pyroelectric vapor sensor 1 and a cross-sectional view (b), and FIG. 3 shows an external perspective view.

The pyroelectric vapor sensor 1 includes a ceramic plate 15 having a pair of opposing electrodes 13.14 on a heat conductive plate 2, and a lead portion 4 led out from the pair of Ag electrodes 13.14.
One of the electrodes 13 is a folded electrode covering part of the first and second surfaces of the ceramic 15, and the other electrode 14 is disposed on the second surface of the ceramic 15. (Electrode 13
．． The pyroelectric element 14 and ceramic 15) is kept in thermal contact with the metal plate 2 by an adhesive 16 such as silicone. Although it also serves to fix the lead portion 4, the pyroelectric element is covered with a coating agent 17 made of silicone or the like mainly for the purpose of moisture proofing.

The actual operation will be explained. When hot steam hits the metal plate 2, the metal plate 2 → adhesive 16 → pyroelectric element ceraξ
Heat transfer occurs in the order of step 15, and the pyroelectric element generates a polarized current due to the pyroelectric effect in response to the transferred heat. Depending on this polarization flow, it is possible to determine whether or not steam is input to the heat-conductive plate 2.

FIG. 4 shows a high-frequency heating device with a pyroelectric steam sensor, showing one embodiment of the present invention.

The output of the pyroelectric steam sensor 1 enters the controller 9, and the controller 18 controls the radio wave emitter 19 and the cooling fan 20 according to the signal.
controls the operation of

A food product 22 is placed in the heating chamber 21 , and a portion of the cooling air from the radio wave emitter (magnetron in this case) 19 is guided into the heating chamber 21 via a duct 23 by a cooling fan 20 . A portion of the cooling air is shown by a solid arrow 24, and a solid arrow 25 represents air containing water vapor, oil, etc. generated from the food.

The cooling air and the air containing water vapor and oil generated from the food pass through the exhaust section 26 and reach the louver 28 of the body cover 27.
It is sent to the outside.

On the other hand, there is another suction hole 29 in the heating chamber 21, and a part of the steam 30 passes through the suction hole 29 and passes through the pyroelectric vapor sensor 1.
After the heat is transferred to the body cover 27, it is sent out from the louver 31 of the body cover 27.

The cooling air 32 from the cooling fan 20 is also used to cool the pyroelectric steam sensor 1 and to suck out a part of the steam 30, and the source of the cooling air is the external air 33.
is adapted to be taken in through the hole 34 of the body cover 27.

With the above configuration, the high-frequency heating device with a pyroelectric steam sensor detects the finished state of cooking. Of course, you can use the same principle with other cookers as well.

FIG. 5 shows the output when the pyroelectric steam sensor 7 is used in a high-frequency heating device, which is extracted as a frequency characteristic using a spectrum analyzer. A is the signal before boiling, and B is the signal after boiling. As you can easily imagine from this waveform, in order to increase the S/N, a low-pass filter (LP
It is better to use F).

FIG. 6 is a block diagram showing the inside of the controller.

As described above, the pyroelectric vapor sensor 1 generates a polarization current by being subjected to a thermal change due to boiling vapor or the like. Inside the controller 1, there is a sheet resistor 35 for extracting the polarization current as a voltage value, and a capacitor 36 for temperature characteristic correction (stabilization) of the pyroelectric vapor sensor 1. As described in Fig. 5, it is filtered by LPF 37 (cutoff 4H2), amplified by amplifier 38, rectified by rectifier 39, and judged by microcomputer 40 whether it is at the detection level. The configuration is such that a control signal is sent to the heating means 41 of. (Of course, it is also possible to control without using a microcomputer.) FIG. 7 shows another embodiment. The lead 4 is fixed using a fixture 42.

Effects of the Invention As described above, the present invention fixes the pyroelectric steam sensor to the main body of the cooking device, thereby preventing the lead from being pulled or bent during the assembly process or iii*. Since stress is not applied to the bonded part with the electrode and failures such as element peeling and electrode peeling can be prevented, it is possible to provide a highly reliable sensor and a cooking appliance with a sensor.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a main part of a pyroelectric steam sensor fixed to a cooking appliance showing an embodiment of the present invention, Fig. 2a is a plan view of the pyroelectric vapor sensor, and Fig. 2 is a cross-sectional view of the same. Figure 3 is a perspective view of the same, Figure 4 is a sectional view when the pyroelectric steam sensor is used in a high frequency heating device, Figure 5 is a frequency characteristic diagram of the output of the pyroelectric steam sensor, and Figure 6 is a block diagram of the controller, FIG. 7 is a sectional view of essential parts showing an example of the same location, FIG. 8 is a perspective view of a conventional absolute humidity sensor, and FIG. 9 is a conventional high-frequency heating device with an absolute humidity sensor. Figure 10 is a block diagram of a conventional pyroelectric vapor sensor. 1... Pyroelectric steam sensor, 3... Body guide, 4... Lead, 18... Controller, 19... Heat B (radio wave emitting part). f-・-Ko wL type 11 Qi (Nsa 3--Ne body voice Ir 4...Leat 2nd figure fig.?...-!I!, type P, MA 7 assembly lδ---Il
1 擲Xia・f9- 庶η(Den Shunki Lung Scale) Fig. 7 z Fig.

Claims (1)

[Claims] A pyroelectric vapor sensor includes a heat conductive plate, a ceramic having a pair of electrodes on the plate, a lead led out from the plate or the electrode, and a heat source inside the main body. A cooking appliance with a pyroelectric steam sensor, wherein the lead of the pyroelectric steam sensor is fixed to a part of the main body.