WO1982001251A1 - Sensing circuit - Google Patents

Abstract

A sensing circuit for controlling the heating condition in an electric range, an electric oven, etc. A sensing element (1), which detects, as the change of impedance, the amounts of various gases such as vapor discharged from heated foods, has electrode plates (2) and (3) provided on both the surface thereof, respectively. The electrode plate (2) is used for heating the sensing element (1) and connected to a first electric source (10). The electrode plate (3) is used for measuring the impedance of the sensing element (1) in co-operation with the electrode plate (2) and its current path includes a second electric source (11) having a different frequency from that of the first electric source (10) and a filter (12) for blocking the entrance of current from the first electric source (10) into the current path. Such a construction permits an exact detection of the heated condition on the foods.

Description

 Specification

 Title of invention

 One sensor circuit

 Technical field

 The present invention relates to a control circuit for detecting various amounts of water vapor and various gases emitted from food with a sensor element and controlling various functional components such as a cooking device.闋

 Background art

 In heating controllers, such as microwave ovens and electric heaters, which are currently in practical use, the state of heating of food is measured, and the amount of water vapor and various gases released from the food is sensed by sensor-element elements. Some automatically detect the change in impedance and automatically control the heating of food.

Fig. 8 shows the composition of the above-mentioned sensor-element part, and around the sensor-element ^{1 /} , there is dust adhering to this sensor-element ^ and oil vapor emitted from food or from food. A coil-shaped heater ² is provided to prevent the sensitivity from being lowered by burning out the components. The heater ² and the sensor element ^{1 /} are connected to each other by a current flowing into the heater ^{2 /} and a current flowing into the sensor ^{2 /} A predetermined space St is provided to prevent the control from being performed incorrectly, regardless of the amount of control.

However the sensor - element and the heat over release the data ^, Heater ^2, the sensor - the heat transfer elements ^{1 /} to the Ruru惡Ku heat - the motor ^{2 /} Ne flows a large current Barurasu, power consumption Is extremely large

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-· · DISCLOSURE OF THE INVENTION-Accordingly, the present invention is capable of accurately performing heating control and the like in a sensor-control circuit for controlling various functional components such as a cooking device, and further reducing power consumption of a heater. It is to make it.

 Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a perspective view of a principal part of a sensor-control circuit showing an embodiment of the present invention, as viewed from the front side, FIG. 2 is a perspective view of the principal part, viewed from the back side, and FIGS. Fig. 6 is a block diagram showing the electrical connection of the main parts, Fig. 6 is a circuit diagram showing an electrical equivalent circuit of Fig. 5, Fig. 7 is an equivalent circuit diagram obtained by simplifying Fig. 6, and Fig. 8 The figure is a perspective view of a conventional example. BEST MODE FOR CARRYING OUT THE INVENTION

In FIGS. 1 and 2, the sensor element 1 is made of, for example, a magnesium pinel monolter (MgCrO ^ -Ti0 ₂ ) ceramic. The electrode plate 2 and the second electrode plate 3 are provided in contact with both sides of the sensor-element 1. 1st, 1st

2 of the electrode plates 2, 3 are for example those having a漦化Ruteni c arm (Hu0 ₂₎ by being created Contact] ?, predetermined resistance value. Lead wires 4,. 6 are electrically connected to the first electrode plate 2, and leads 5 are electrically connected to the second electrode plate 3. The first electrode plate 2 is particularly capable of generating heat. When a voltage is applied between the lead wires 4 and 6 (the first electrode plate 2 generates heat, the sensor - heating the element ^1, the sensor - also to burn off a was oil vapor and the like from Hoko Li and food in the air adhering to the element 1 Nodea

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You. Li - lead wire Ryo is moth - der those electrically connected to the cathode electrode 8 also, guard electrode 8 may Retabe made Aluminum Na (Alpha £ ₂ .theta.3) - Contact on scan 9 Printed and wired around the lead wires 4, 5, and 6. The lead wires ⁴ , ⁵ , ⁶ , 7 penetrate the base 9 and are fixed to the base ⁹ at the penetrating portions.

In FIG. 3, a ^first power supply 1 た め for causing the ^first electrode plate 2 to generate heat is electrically connected to a lead wire ⁴ and a lead wire ⁶ , and is connected to a ^first ground. ^It is also electrically connected to ¹⁴ . Sensor-A second power supply provided to measure the impedance of element 1

One end of 11 is electrically connected to a lead wire 4 or 6 via a filter 12, and the other end is electrically connected to a second ground 15. In here, the first and second power supply ^{1 Ο, 1 1} of the frequency Ru so different, et al. Further, a resistor 13 is electrically connected between the lead wire 5 and the second ground ¹⁵ .

FIG. 4 shows another embodiment of the present invention. In this embodiment, a filter 12 is provided at a connection portion between a lead wire 5 and a resistor 13. Shifted in Seyofu I filter - ¹ 2 ^and the ^second power supply ¹ 1 energizing route, That ^second power supply ^{1 1} → sensor - element ¹ - resistor ^{1 3} second ground 1 5 → second power supply 1 ^It is provided in the first circuit, and functions to block the current from the first power supply and pass the current from the second power supply 11.

FIG. 5 shows an embodiment using a DC power supply 1 as a first power supply 1 、 and a capacitor ¹² ′ as a filter ^12, and FIG. 6 shows an equivalent circuit thereof. Is shown. In such a configuration, the impedance of sensor 1 element ¹

1 8 and R _s, obtaining the relationship between the output voltage V_〇 from the Lee emissions bicycloalkyl one dance R _s and resistor 1 ^3. Now, the second power supply 1 1 V _s, the value of capacitor 1 ² 'C, the equivalent resistance 1 ⁶ of the ^first electrode plate ^2, 1 Ryo ^, r _2, the values of the resistors 1 3 R 〇 Wherein the first equivalent resistance of the electrode plates 2 tau, r ₂ originally der D that functions as an electrode, is the value rather _{small, r «j, r 2"} H s, and the ^R 0 Can be shown, so ^, r ₂ can be ignored.

 Therefore, the equivalent circuit for the signal can be simplified as shown in FIG.

R

 V 〇

 o = V S

この式から明らかな よ うにセンサー素子 1 のィ ンピーダンス R _s に対して、 出力電圧 V〇 は一義的に求まる。

As is clear from this equation, the output voltage V〇 is uniquely determined with respect to the impedance R _s of the sensor element 1.

In this case, the impedance R _s of the sensor element ¹ changes according to the amount of water vapor and various gases emitted from the food, so that the heating state of the food can be detected based on the output voltage 0 and the food can be automatically controlled. Industrial applicability

As is clear from the above description, the present invention uses the first electrode plate used as a heater for burning off dust in the air adhering to one sensor element and oil vapor from food, etc. to the sensor element. Since they are provided in contact with each other, heat transfer is very good and the power consumption can be reduced by that much. Further, the frequencies of the first and second power supplies are made different, and the power supply path of the second power supply is also provided. With the intervening filter, 2nd :? I The current from the first power supply is prevented from flowing into the power supply path of the power supply, so when it is used in a cooking device, for example, the heating status of the food can be accurately determined according to the amount of water vapor and various gases emitted from the food. And the heating control can be performed accurately.

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Claims

― Ό— • Scope of billing  1. A flat sensor element, a first electrode plate provided on one surface of the sensor-element and having a predetermined heating resistance, and a first electrode plate provided on the other surface of the sensor-element. A second power supply electrically connected to the second electrode plate, a first power supply electrically connected to the first electrode plate, and a second power supply electrically connected to the first electrode plate and the second electrode plate. In addition to the above, the frequencies of the first and second power supplies are made different, and the current path of the second power supply is blocked and the current of the second power supply is passed through the current supply path of the second power supply. Sensor-control circuit characterized by the provision of a filter.  2. A sensor control circuit according to claim 1, wherein the first power supply is constituted by a DC power supply, and the filter is constituted by a capacitor. .