JPS58186017A - Level indicating device - Google Patents

Abstract

PURPOSE:To exactly display a level of a liquid, by providing plural electrodes in a suport vertically provided in a storage tank, connecting each electrode to a high frequency power source, constituting a level display of a detector, a decoder, an arithmetic device, etc., and connecting the detector to the storage tank. CONSTITUTION:A high frequency power source 13 is operated, and a current value is detected by detectors 14a-14c from the electrostatic capacity between electrodes 12a-12c and a storage tank 10. Since the distance between the bottom wall of the storage tank 10 and the electrodes 12a-12c is known already, a digital signal is outputted to an arithmetic device 19 from a decoder 18, is processed by the device 19, and thereafter, the digital signal is outputted to a level indicator 20 from the device 19, and a level l0 of a liquid is indicated roughly. Even if the conductivity of a fluid in the storage tank is varied, said signal is processed by the arithmetic device in accordance with a current value detected by the detector, the distance between the bottom side of the storage tank and the lower end of the electrode, and the length of the electrode, and is outputted to a level indicator, by which a level of a fluid can be indicated exactly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a level indicating device, and particularly to a level indicating device suitable for indicating a change in the level position of a fluid stored in a reservoir and having a varying dielectric constant inside the reservoir from outside the reservoir. This relates to a level indicating device.

An example of a conventional level indicating device will be explained with reference to FIG.

Fig. 1 is a configuration diagram of a capacitive level indicating device with a single fixed electrode.Inside the metal storage tank lO, there is a support 11 molded from a fluid-impermeable and electrically insulating material. are laid out in layers. Support 11
A high frequency electrode (hereinafter abbreviated as electrode) 12 is placed inside. A high frequency power source 13 is connected to the electrode 12 . An electric signal detector (hereinafter abbreviated as "detector") 14 of a level display device is connected to the high frequency power source 13 via a 15° resistor and an inductance 16. Electric signal detector 1
4 is connected to the outer wall of the storage tank IO.

Note that a level display meter (not shown) of a level display device is connected to the electric signal detector 14.

If the fluid is stored in the storage tank 10 at the level shown in FIG. Indication is given by detecting the current value and outputting this current value to the level display meter.

With such level indicating devices, the temperature in the storage tank.

When the pressure, fluid composition, etc. change, the dielectric constant of the fluid is
Because of these changes, the current value detected by the detector will differ even if the fluid level is at the same position, and therefore the level indication on the level indicator will be inaccurate. there were.

An object of the present invention is to provide a level indicating device capable of accurately indicating the level with a level indicator even if the conductivity of the fluid stored in the storage tank changes by eliminating the above-mentioned drawbacks. There is a particular thing.

A feature of the present invention is that a plurality of electrodes are installed on a support made of a material that is impermeable and electrically insulating and is installed vertically in a storage tank while maintaining electrical insulation from adjacent electrodes. At the same time, each electrode is connected to a high frequency power source, and a level display device is connected to a number of detectors corresponding to the number of electrodes, a decoder connected to the detector, a nuclear decoder, and a computing unit connected to the detector. and a level indicator connected to the arithmetic unit, the detector is connected to a high frequency power source via a resistance and inductance, and the detector is connected to a storage tank, so that the amount of water stored in the storage tank is The purpose is to enable accurate level indication with a level indicator even if the dielectric constant of the fluid in the fluid changes.

An embodiment of the present invention will be described with reference to FIG.

FIG. 2 is a block diagram of a level indicating device according to the present invention. In FIG. 2, the same devices as those in FIG.

The electrodes 12 a to 12 c are arranged inside the support 11 while being electrically insulated from adjacent electrodes. electrode 12
a~12 c 1. t, connected to the high frequency power source 13.

The number of level display devices corresponds to the number of electrodes 12 a to 12 c, in this case, three detectors 14 a to 14
c, detectors 14a to 14c'', :''a decoder 18 connected via an amplifier 17, an arithmetic unit 19 connected to the detector 14a=14c via the decoder 18 and the amplifier 17, and an arithmetic unit 19 It consists of a level display meter and a connected level display meter. Detector 14 B = 14 c
is resistance 15a~15C, inductance 16a~
It is connected to the high frequency power source 13 via 16c and to the outer wall of the storage tank IO.

In addition, the frequency of the high frequency power supply 13 and the inductance 1
6a to 16c, the temperature and pressure inside the storage tank 10.

Even if the composition of the fluid changes and the capacitance changes due to changes in the dielectric constant of the fluid, changes in the electrical signals detected by the detectors 14a to 14c, such as changes in current values, do not exceed the maximum value. In addition, the capacitance and the current value are set in a range where the relationship is a linear function.

The fluid in the reservoir 10 is at the level shown in FIG.

), then the fluid level order 1 (J,) is determined as follows.

First, the high frequency power supply 13 is activated, and the electrodes 12a-12c are
From the capacitance between the detector 14 and the storage tank 10, a = 14
Detect the current value with c. In this case, the detector 14a~
As shown in Fig. 3, the current value detected by the detector 14c is at a high level at the detector 14a, at a low level between 4 and high level at the detector 14b, and at a low level at the detector 14c. , and the bottom wall of the storage tank 10 and the electrodes 12a to 12
Since the distance to c is known in advance, the decoder 18 outputs a digital signal to the arithmetic unit 19, and after the arithmetic processing is performed by the arithmetic unit 19, the arithmetic unit 19 outputs a digital signal or an analog signal for each level display. , the fluid level (
l! . ) can be given general instructions. Also, the fluid level (t!
. ) is specified precisely as follows.

The current value (d) detected by the detector 1114b is output from the detector 14b to the arithmetic unit 19 via the amplifier 17.

Then, calculate! At a19, the fluid level (10) is calculated using the following equation. This result is output as a digital signal or an IJ analog signal to a level display, where the fluid level <t. ) is accurately indicated.

Here, 10: Fluid level l, : Distance between the bottom wall of the storage tank and the lower end of the electrode 12b ■, : Detected current value ■, Current value at the second detector 14 b High level I2: Current value at the detector 14 b Low level R,: Length of pole 12b In a level indicating device such as this embodiment, even if the conductivity of the body stored in the storage tank changes, the current value detected by the detector, the storage tank The fluid level can be accurately indicated by calculating the distance from the bottom wall to the lower end of the electrode and the length of the electrode using a calculator and outputting the result to the level indicator.

As explained above, the present invention has a plurality of electrodes mounted on a support vertically installed in a storage tank made of a material that is impermeable to fluids and electrically insulating, and is electrically insulated from adjacent electrodes. At the same time, each electrode is connected to a high frequency power source, and a level display device is connected to a number of detectors corresponding to the number of electrodes, a decoder connected to the detector, and a level display device connected to the decoder and the detector. It consists of a calculator, a level display meter connected to the calculator, and a detector connected to a high frequency power source via a resistor and an inductance.
Additionally, by connecting the detector to the storage tank, the level of the fluid stored in the tank can be calculated and indicated, so even if the dielectric constant of the fluid changes, the level indicator can accurately indicate the level. There is an effect that can be done.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional level indicating device, and Fig. 2 is a block diagram of a conventional level indicating device.
A configuration diagram showing an embodiment of a level indicating device according to the present invention,
FIG. 3 is a diagram showing the relationship between the fluid level position and the current value of the detector. 10...Storage tank, 11...Support, 1
2 a to 12 c... electrode, 13... high frequency power supply, 14 a to 14 c... detector, 1
5 a to 15 c...Resistance, 16. from 16
c...Inductance, 17...Amplifier, 18...Decoder, 19...Arithmetic unit, Addition...Level display hand, 7. Figure 31'1, 8. yft# /) Level σ L

Claims (1)

[Claims] 1. A support made of a fluid-impermeable and electrically insulating material, a high-frequency electrode, and a level display device;
In the level indicating device, the support is installed vertically in a storage barrel, and the support is provided with a plurality of the high-frequency electrodes inside the support while being electrically insulated from adjacent high-frequency electrodes; , each high-frequency electrode is connected to the high-frequency power supply, and the level display device is connected to a number of electric signal detectors corresponding to the number of high-frequency electrodes, a decoder connected to the nuclear electric signal detector, and the decoder and the electric signal. It consists of a computing unit connected to a signal detector, and a level display meter connected to the computing unit, and the electrical signal detector is connected to a high frequency power source through a resistance and inductance. % connected to said storage tank
level indicating device.