JPH05126616A - Liquid level meter - Google Patents

Abstract

PURPOSE:To reduce the liquid level measurement error by laminating a heating element, an insulator, and a superconductor in this order on a finely divided chip-like ceramic board, and connecting the preset number of unit chip elements covered by a protective film on them to form a liquid level detection section. CONSTITUTION:A heater 11 is bent and formed on a ceramic board 13, and an insulating thin film 4 is formed on it. An oxide conductor thick film 12 is bent and formed on it, and a protective film 15 is coated to form a unit chip element 1. The required number of the unit chip elements 1 are connected to form a liquid level detection section. The partial failure of the liquid level detection section can be easily repaired by the replacement of the unit chip element 1, the shape and size of a container can be merely coped with the connecting work, and it is suitable for mass production.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid level meter using a superconductor for detecting the liquid level of liquefied gas such as liquid nitrogen.

[0002]

2. Description of the Related Art In a liquid level meter using a superconductor, while a superconductor portion immersed in a liquid is in a superconducting state, a portion outside the liquid surface is in a normal conducting state. It was used, from the normal conduction state part length to the total length,
The liquid level, which is the immersion portion length, is determined. And many proposals have already been made for this kind of thing.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
A brittle substance such as a sintered body made of an oxide superconductor has to be processed into a rod or a film on the substrate. Therefore, there is a problem in strength or uniform processing of these materials. That is, there is a problem not only technically but also economically in forming a superconducting film having a certain length and a uniform thickness and film quality on a substrate.

Further, the liquefied gas container has various shapes and sizes depending on its application, and it is neither practical nor wasteful to manufacture a liquid level meter having a predetermined length from the beginning. .. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid level meter that can be arbitrarily adapted without depending on the shape and size of a container.

[0005]

In order to achieve the above-mentioned object, the present invention provides a heating element on a subdivided chip-shaped ceramic substrate, forms an insulating film covering the upper surface of the heating element, A unit chip element is formed by laminating an oxide superconductor thick film whose seaside temperature is higher than the temperature of the liquefied gas on the upper surface of the film, and covering the oxide superconductor thick film with a protective film. A predetermined number of liquid level detectors were connected. Further, a heating resistor and a superconductor thick film are formed in parallel on the same surface of the chip-shaped ceramic substrate while maintaining electrical insulation between them, or a heating resistor is provided on one surface of the chip-shaped ceramic substrate. , A superconductor thick film is formed on one surface of the other side, and the heating resistor and the superconductor thick film are covered with a protective film to form a unit chip element, and a predetermined number of these unit chip elements are connected to form a liquid level detection unit. ..

[0006]

When a predetermined number of units are connected, the number should be the number that matches the container, and when detecting the liquid level, the unit chip element in the position in contact with the liquid and the unit in contact with the gas above the liquid level. Since the unit chip element is small and the unit chip element is small, the oxide superconductor thick film of the unit chip element in the part in contact with the gas above the liquid surface shows normal conduction. Since only the oxide superconductor of the unit chip element in contact with the liquid exhibits superconductivity, the measurement error of the liquid surface is reduced.

[0007]

Embodiments will be described below with reference to the drawings. Figure 1
FIG. 3 is an enlarged principle view showing a liquid level meter according to the present invention. In the figure, the unit chip elements 1 have the same structure, and a required number of them are connected. Although the structure of the unit chip element 1 will be described later, the portion of the unit chip element 1 connected by a predetermined number serves as a liquid level detection unit. The heater power source 2 is connected to the heater 11 inside the unit chip element. The heater is for clarifying the temperature gradient between the inside and outside of the liquid surface when the liquid surface detection part is immersed in the liquid, and the black portion in the figure indicates the heater.
Represents 11.

Thick oxide superconductor film 12 in a unit chip
The liquid level measuring power source 3 is connected to. In the figure, the shaded portion represents the oxide superconductor thick film 12. In addition, the liquid level detection principle is the same as in the prior art, where a constant power is supplied from the heater power source 2 to the heater 11, while the oxide superconductor thick film 12 is used.
In addition, a constant current is made to flow while being measured by the current system 5 from the liquid level measuring power supply 3, and at this time, the liquid level is measured from the voltage value detected by the voltmeter 4.

2 to 5 are exploded views for explaining the structure of a unit chip constituting the liquid level meter. First, in FIG. 2, the heater 11 is bent and formed on the ceramics substrate 13, and an insulator thick film 14 is formed on the upper surface thereof as shown in FIG. Then on top of it, as shown in FIG.
The oxide superconductor thick film 12 is formed by bending, and on it,
As shown in FIG. 5, the protective film 15 was formed. In short, heating resistors (heaters), insulators,
The superconductor was formed in order, and finally the upper surface was covered with a protective film to form a laminated structure.

FIG. 6 shows an example of the entire structure for detecting the liquid level of a liquefied gas such as liquid nitrogen using a liquid level meter.
The nitrogen container 16 is filled with a liquefied gas 17 such as liquid nitrogen, and a detection unit in which unit chip elements are connected to the liquefied gas
18 are installed. The heater power source 2, the liquid level measuring power source 3, etc. are as described above. .

In the actual production of the unit chip element,
As a ceramic substrate, a yttria-stabilized zirconia substrate and an alumina substrate were used, and the thickness was 10 mm square and the thickness was 1 mm. As the heating elements, platinum heating resistors containing 40% by volume of zirconia and alumina were used, and the thickness was 30 μm and the width was 200 μm.
It is formed by bending it to a substrate shape with a resistance of 20 μm.
It was set to ~ 30Ω. The insulating film is a zirconia-based film, about 50 μm on the entire surface except for the lead-out terminals for connecting the heating resistor.
Formed in thickness.

As the superconductor film, a yttrium oxide superconductor film is used, and the width is 300 to 500 μm, the length is 24 mm,
The thickness was set to 30 μm. Further, as a protective film, a polyimide resin or GE7 manufactured by General Electric Company is used.
A polymer film of 031 varnish was used.

The film is formed by screen printing except for the protective film, the firing temperature is set to 1000 to 1500 ° C. for the platinum heating element film and the insulator film, and 950 to 980 ° C. for the oxide superconductor.
And The protective film is formed by a spin coating method or a coating method, and the polymer is polymerized at about 300 ° C. with GE7.
The 031 varnish was formed at about 150 ° C. Then, as the detection unit 18, the unit chip element created as described above is used.
Ten pieces were connected to form the structure shown in FIG.

FIG. 7 shows the measurement results of the liquid level meter using the detector thus created, and the vertical axis of the figure is the output standardized by setting the voltage to 100 when the liquid level is 0. Voltage,
If the horizontal axis is the liquid level height, an output voltage that is substantially proportional is generated as the liquid level height decreases. The total power supplied from the heater power supply to the heating resistor is about 2
W and the current flowing through the superconductor was about 1 mA.

The unit chip element described in the above embodiment has been described as a structure in which a heating resistor, an insulator, a superconductor and the like are sequentially laminated on a substrate, but the invention is not limited to such a structure. FIG. 8 shows another embodiment of the unit chip element. In this embodiment, a heating resistor (heater) 11 and a superconductor thick film 12 are provided in parallel on a ceramic substrate 13 while electrically insulating each other. Is.

FIG. 9 shows still another embodiment. In this embodiment, a heating resistor (heater) 11 and a superconductor thick film 12 are provided on a ceramic substrate while maintaining electrical insulation therebetween. Same as, but different in that they are arranged by bending each.

FIGS. 10, 11 and 12 show still another embodiment. In this embodiment, a heating resistor (heater) 11 is provided on one surface (front surface) of a ceramic substrate (FIG. 10), and the other surface is formed on the other surface. The superconductor thick film 12 is provided on the (rear surface) (FIG. 11), and its side surface is as shown in FIG. The upper surface of each unit chip is coated in the same manner as above. It is obvious that the same effect as that of the above-mentioned embodiment can be obtained by using this type of unit chip.

[0018]

As described above, according to the present invention, a heating element, an insulator and a superconductor are provided on a chip-shaped ceramic substrate which is subdivided, and the unit is formed by covering the upper surface of the superconductor with a protective film. Since the chip elements are formed and a predetermined number of these unit chip elements are connected to each other to form the liquid level detection unit, the following effects are achieved. A partial failure of the liquid level detector can be easily repaired by replacing the unit chip element. Since the liquid level detection unit is formed by connecting the unit chip elements, only one type of device needs to be produced, which is economical and suitable for mass production. A point-type level gauge can be achieved with only one unit chip element. Can be used for various shapes and sizes of containers only by connecting them.

[0019]

[Brief description of drawings]

FIG. 1 is a principle view showing an enlarged liquid level meter.

FIG. 2 is a diagram in which a heating resistor is provided on a substrate.

FIG. 3 is a diagram in which an insulator is provided on the upper surface of a heating resistor.

FIG. 4 is a diagram in which a superconductor is provided on an upper surface of an insulator.

FIG. 5 is a diagram in which the upper surface of a superconductor is covered.

FIG. 6 is a diagram showing an example of the overall configuration for detecting the liquid level of a liquefied gas such as liquid nitrogen using a liquid level meter.

FIG. 7 is a diagram showing a measurement result of a liquid level meter.

FIG. 8 is a diagram showing another example of the unit chip element.

FIG. 9 is a view showing still another embodiment of the unit chip element.

FIG. 10 is a front view of still another embodiment of the unit chip element.

FIG. 11 is a rear view of FIG. 10.

FIG. 12 is a side view of FIG.

[Explanation of symbols] 1 unit Chip element 2 Heater power supply 3 Liquid level measurement power supply 4 Voltmeter 5 Ammeter 11 Heating resistor 12 Superconductor thick film 13 Ceramic substrate 14 Insulator 15 Protective film 16 Nitrogen container 17 Liquefied gas 18 Detector

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Shimizu Kenji Shimizu 5310 Sangejiri, Kumagaya-shi, Saitama Chichibu cement Co., Ltd.Development headquarters Company Development Division

Claims (3)

[Claims] 1. A heating element is provided on a chip-shaped ceramic substrate that is subdivided, an insulator is formed to cover the upper surface of the heating element, and a superconductor is laminated on the upper surface of the insulator, and the superconductor is also formed. A liquid level meter, wherein an upper surface is covered with a protective film to form a unit chip element, and a predetermined number of the unit chip elements are connected to form a liquid level detection unit. 2. A unit chip element for a liquid level gauge, wherein a heating element and a superconductor are arranged on the same surface of a subdivided chip-shaped ceramic substrate so as not to contact each other. 3. A unit chip element for a liquid level meter, wherein a heating element is provided on one surface of a subdivided chip-shaped ceramic substrate and a superconductor is arranged on the other surface.