JPS60143722A - Capacitance type three-way displacement detector - Google Patents

Abstract

PURPOSE:To make it possible to detect displacements by one probe, by partially dipping a probe, wherein specified three pairs of facing electrodes are arranged on the same circumference, into a fluid, and detecting the three-way displacements based on the signals at the other common connecting point obtained by imparting a specified signal to one pair of electrode plates. CONSTITUTION:Three pairs of outer and inner electrodes 3a, 3b, 4a, 4b and 5a, 5b are arranged so that the inner and outer electrodes face to each other. The outer and inner electrodes have the same areas, respectively. Thus partially cylindrical facing electrodes 3, 4 and 5 are formed. The electrodes are arranged on the same circumference at the bottom of a container at an equal interval, and a probe is constituted. Two- phase signals V4 and V5 are obtained from multiple-phase signals by a transformer 6. The signal V4 is imparted to a transmitting circuit 7. Three-phase AC signals V1, V2 and V3 are imparted to the electrodes 3, 4 and 5. The signal at a common connecting point P, which is formed by said signals and the signal V5 through a reference capacitor 8, is amplified by an amplifier 9 and separated by a decoding circuit 10. A liquid level signal V7 is obtained from the two-phase signal component. A slant direction signal V8 and a slant angle signal V9 are obtained from the multiple-phase signal components.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention utilizes changes in capacitance to detect displacement in three directions, such as changes in fluid inclination direction, inclination angle, and liquid level. Regarding the location.

<Prior art> When measuring the fuel liquid m in an aircraft fuel tank, a probe is placed upright in the fuel tank, thereby detecting the fuel level in the tank, and based on this detection result, the fuel liquid level is determined. was calculated.

Since the fuel tank is installed in a limited space such as a wing, its shape is irregular, and if the fuel tank is detected using a single tank, when the aircraft is turning, the fuel The output detected by the plow 1 changes depending on the direction of inclination of the liquid level, making it impossible to perform accurate measurements.

For this purpose, in the conventional device, at least three or more probes are placed upright in the fuel tank, and these probes D-1 detect 1. ': Based on the output, the tilt direction, tilt angle, and fuel level I3I]! I-J i
iQ '71 was applied to ensure correct fuel flow.

However, with such conventional devices, three or more IC probes must be installed in order to measure the fuel liquid m, which increases the cost. Depending on the method, displacement signals in three directions can be expressed as l! I had to do a complicated 51 steps each time I wanted to go to school.

<Purpose> The purpose of the present invention is to enable the detection of a change in the direction of 31J (Gz) with a single probe, to simplify the configuration of the detection part, and to
In addition to being able to be configured at low cost, it is also possible to configure multiple
- The object of the present invention is to realize a capacitive three-direction displacement detecting device that does not require complicated calculations that are required when using a tube.

<Configuration of the Invention> The configuration of the present invention is such that a probe having three or more opposing electrodes having the same area and the same gap arranged at equal intervals on the same circumference is partially immersed in a dielectric fluid. One phase of three or more sets of multiphase signals each modulated by one phase of two-phase signals and having a different frequency from this signal is applied to one plate of the counter electrode, or one phase of two-phase signals is applied to one plate of the opposing electrode. One phase and a multiphase signal are applied to the alternating current U, and among the signal voltages generated at the common connection point of the other plate of the opposing electrode, the two phase components are
The other phase of the phase code is applied to the reference volume ■ and compared with the voltage obtained by 1!7, a voltage corresponding to the change in the total capacitance of the counter electrode is obtained, and from this, the liquid level of the fluid is determined. A signal related to the level is obtained, and the magnitude of the multiphase signal component of the signal voltage generated at the common connection point as well as the phase difference of this component from the reference signal are detected to detect the level of the signal voltage generated at the common connection point. Signals related to the direction of inclination and the angle of inclination of the surface are obtained. There is a cross-sectional view C of the detection portion taken along the plane A-A shown in FIG. In these figures, 1 is a container such as a fuel tank (1 is a container such as a fuel tank) in which a dielectric fluid 2 is placed.
In FIG. 2 only its bottom part is shown. ), 3.4
．． 5 is a partially cylindrical counter electrode arranged vertically at equal intervals on the same circumference centering on C at the bottom of this container, and is also the same as the outer electrodes 3a, 4a, 5a having the same area. - inner electrodes 3'b, 4b with area;

5b and 5b face each other with the same distance of 1". These constitute J and P[l-B.

If container 1 is tilted and the liquid level of fluid 2 becomes I, fluid 2
The state of each electrode immersed in the water is as shown in Figure 3. Third
The electrode portions are shown expanded according to the figure number, and to simplify the explanation, each of the opposing rri poles 3, 4, and 5 is representatively shown as one plate. S31°S41. S51 is fluid 2
represents the area of 3.4°5 part of the electrode immersed in
2,842,852 represents the area of the part exposed to the atmosphere.

α is the direction of inclination, θ is the angle IQ corresponding to the width of electric ti3.4.5 (however, θ<(2/3)・π), L is the height of the inclination, and the angle of inclination is the center C empty? Utfi3.4
．． ．． When the distance X to 5 is 1, it is expressed as arctanl.

In this relationship, if the area of the counter electrodes 3 and 4.5 is S1 when water is 1 L, and the area of the part where these electrodes are immersed in fluid 2 is So, then the area of each counter electrode immersed in fluid 2 is Area of part s31゜(α-(π/2))]d
θ = So 1L [Cos ((π/2) −α) −Oo
S(θ+(π/2)−α)] (α−(π/2))ldθ=SO+L LGO5((7/6),−π−α)−co
s(θ0(7/6)・π−α)]fα−(π/2))]
dθ −8o +1. − [Qos ((11/6) ・π−
α] −Cos (θ+ <11/6) ・π−α
Fuco... (3) Similarly (5-1, in the popular part, fas32゜842, S52 is expressed as follows.

S 3 2 = (S S o ) L [Co s
((π/22)-α)-QO5(θ-1(π/2)-
α)]...(4) 842= (S-8o) -L [Cos ((7/
6)・π−α)−CO8(θ+(7/6)・π−α)1
...(5) S52= (S-8o)-L [CO8((11/6
)・π−α)−CO5(θ+(”II/6)・π−α)
1...(6) If the constant related to the dielectric constant of the fluid 2 and the gap between the electrode plates is set to 1, and the constant related to the popular permittivity and the gap is set to 2, then the counter electrode 3°4 , 5 (1)
nm Capacity C3, C4, 05+4 JJ, Lower (D
J: It can be expressed as ').

C3 = 1.3314 ~ 2.832...(7) / C4= 1 ・841 → +2 ・842...
(8) C5= k i ・2 to S51+ ・852・
... (9) The sum of these capacitances is C3+C4→-C5=1・(S31+841+85
1) + k 2・(S32+842+852)・・
・(10) is expressed as (831''-8411-651), (S3
2+S42+552) are 3So and 3 (SSo), respectively, from equations (1) to (6), so (10)
The formula can be expressed as follows.

C3+C4→-05=3kl・So+ 3 to 2・<5-8o) =3 (2 to kl-)・S.

1,3 to 2·S (11) From this equation, it can be seen that the total capacitance depends on So, which is related to the level of the fluid 2.

On the other hand, as shown in FIG. 4, the counter electrodes 3 and 4.5 are placed on one plate as follows:
l... (13) V3=S i n [ωt+ (4/3)-yrl...
(14) 3) Phase alternating current signals Vl, V2. Rie V3,
When the other plate is connected in common, J (occurs at the connection point 8
The composite signal vO can be expressed as J above.

VO= (C3-V1+C4-V2 05-V3)
/(C;3 + 04 +Cb) ... (15) This j( is, from formulas (1) to (14), Vo=1--
[1/((So+(+2・s)/(kl−2>)]
・Sin (θ/2)・S i n [ωt+α−(θ
/2)]...(16) It can be rewritten as In this equation, kl is 2. Since S, 0 is a constant, it is proportional to VOt,
It can be seen that the phase is inversely proportional to So and is out of phase by (α-(θ/2)) with respect to the reference signal L signal of 3 inωt per month.

Therefore, in the present invention, one phase of the two-phase cable is commonly applied to the opposing electrodes 3 and 4.5, and a signal related to the sum of capacitance is detected at the common connection point, and a signal related to the sum of capacitance is detected.
One phase of the multiphase signal is applied to each counter electrode 3.4.5 separately, and from the multiphase signal component of the signal detected at the connection point,
Considering the direction of inclination α of the liquid surface of fluid 2 and the magnitude of the inclination, 3
It detects directional displacement.

The application 1j of the two-phase signal and the multi-phase signal (jS) to the counter electrode 3.4.5 may be provided in the form of a composite signal obtained by modulating the multi-phase signal with a two-phase signal, or It is also possible to time-divisionally apply the mutually transmitted multiphase signals to the intersection U.

FIG. 5 is a block diagram showing a circuit configuration for determining the height, direction of inclination, and angle of inclination of the fluid 2 in the embodiment of the present invention. ,4.5
A composite signal obtained by modulating the multiphase signal with a two-phase signal is given to the multiphase signal. In the figure, the numbers in Figures 1, 2, and 4)
Elements that are the same as those in the above are marked with the same - sign. 6 is 2
In the phase signal generation σJ lance, the middle tap of the secondary coil is grounded, and two-phase IPr@v4. Generate vs.

7 receives electrical energy supply from transformer 6, and 1%
ij' electric (<
3 whose frequency is different from this two-phase phase modulated by :
Phase AC signals Vl, V2. V3 and a reference signal v6 having the same frequency as these flow signals are generated. This reference reliability is based on the three-phase AC signal V1. It doesn't matter if it is the same as one of V2°V3.

If 8 stocks are progressing on one side, the other 1 phase v5 of the above 2 phase phases will be t'L ta% quasi-volume (?i F, opposite type 1!i3
, 4°5, the total tF capacitance a) is set up to detect changes. The other plate of this capacitance n1 is of the opposing type 1M 3 .

4.5 Synthesis (ft, 9
J is this 11. [obtained in This signal is given to an amplifier 9.

10 GJ 41g1J given the output from amplifier 9
A circuit in which the multiphase signal and the two-phase signals are separated. The two-phase signal component is the difference between the bias component connected to the sum of the capacitances of the counter electrodes 3.4.5 and the reference signal component given via the reference capacitor 8, as shown in equation (11). This corresponds to a change in the total sum of the capacitance ffi from the reference value. The demodulation circuit 10 samples this using the two-phase signal v4 given from the lances 1 to 6, shapes the waveform, measures the voltage, obtains a liquid level signal v7, and outputs this to the liquid level display section 11. .

The polyphase signal component is ll[In the S11 circuit 1o,
By performing filtering, phase inversion, addition, etc., the signal component shown by equation (16) is obtained, and the signal component shown in equation (16) is obtained, and the signal component shown in equation (16) is obtained, and the signal component shown in the attached phase difference measurement circuit 12. and the voltage measurement circuit 13. The oscillation circuit 1187/JS t3 reference signal v6 is applied to the phase difference measuring circuit 12 via the 7-way automatic coupler 14 as a signal with the ground potential as a common signal.

The phase difference between this reference signal and the multiphase signal component is detected by this circuit, and is outputted as the tilt direction (8tan 8) to the tilt direction display section 15 at the subsequent stage.

The voltage measuring circuit 13 measures the magnitude of the multiphase signal component, and its output is sent to the tilt angle correction circuit 1G. In the quadrilateral angle correction calculation circuit 1G, the liquid level level signal V7 from the demodulation circuit 10 is applied to the liquid level signal V7, and the correction calculation is made to the human power signal C1. It is a function of the level (() (due to; done to correct the difference?).The tilt angle signal from the tilt angle corrector valve circuit 16 (V≦) is output to the tilt angle display section 17. Ru.

When measuring the liquid purity in a fuel tank based on this output, it is also possible to use these signals according to the shape of the fuel tank. Apply the correct liquid and add the correct liquid. For example, the correction calculation for the case of this size includes the previous n+-! Fuel tank shape, inclination direction and liquid level and 9+71 yen!
A method is adopted in which the same relationship as the one on the right is calculated in advance using the data of the computer using the Compute La Simillet 932 method.

6th R port is a block diagram illustrating a circuit configuration for obtaining the liquid level signal, tilt direction signal, and tilt angle signal in another embodiment of the device of the present invention.

In the embodiment, the multiphase signal and the two-phase signal are alternately applied to the counter electrodes 3.4.5 in a time-division manner. In the figure, the same elements as those shown in FIG.

7' is an oscillation circuit, which generates a three-phase AC signal V1=.

A reference signal v/I' having the same wave number as V2', V3' and these AC signals is generated. 81.82 is an AC signal from the oscillation circuit 7' by the signal given from the signal source 18)3
This is a switch that applies V1=, V2' and two-phase Shintan to the opposing electrodes 3 and 4 as alternating current. The three-phase AC signal v3- is applied to the counter electrode 4 and is used as a two-phase signal. S3 is a switch that applies an AC signal V3- from the oscillation circuit 7- to the inverter 19 in response to a signal provided by the signal source 18. The output of the inverter 19 is given to the reference capacitor 8 as the other one phase of the two-phase signal.

84 outputs the output from the demodulator raio to the switches 81 to 84.
This is a switch that selectively applies to the liquid level display section 11, the phase difference measuring circuit 12, and the voltage measuring circuit 13 in synchronization with S3.

With such a configuration, the multiphase No. 18 component and the two-phase phase component are detected alternately, and the Ic fluid level signal @V7. is derived from these signals. Tilt direction signal V8'+II
rj oblique angle 1. 'i bow■9, )^ Via appropriate signal holding means, frown level display section 11. Tilt direction display section 15 *
I! If output to the inclination angle display section 17, changes in three directions ((Z) can be detected as shown in FIG. 5, as in the embodiment.

Effects> According to the present invention, since displacement in three directions can be detected with one probe, the number of detection parts can be easily configured at a low cost.

Furthermore, conventionally, when multiple probes are used, the 10-beam is stiff, and depending on the delivery method, displacement in three directions (
In order to obtain No. 3, it was necessary to perform a complicated <41 calculation each time, but with the present invention, such a complicated calculation of 81 is no longer necessary.

[Brief explanation of the drawing]

Figure 1 is a plan view of the detection part of the neck strap according to the embodiment of the invention, Figure 2 is a cross-sectional view of the detection part taken along the plane mA-A shown in Figure 1, and Figure 3 is Figure 4 is a diagram showing the state of the electrode immersed in the fluid 2 with the electrode part expanded, and Figure 4 is a connection diagram of the counter electrode of the device according to the present invention.
FIG. J5 and FIG. 6 are block diagrams showing the circuit configuration for receiving the level signal, tilt signal, and tilt angle signal of the fluid 2 in the apparatus according to the embodiment of the present invention. 1... Container, 2... Dielectric fluid, 3, 4.5...
Counter electrode, 6...Transformer, 7, 7'...Oscillation circuit, 8...Reference capacitance, 10...Demodulation circuit, 12...
Phase difference measuring circuit, 13... Voltage measuring circuit, 19...
Inverter, 81-S4... switch. M1 figure 2 figure 3 [-

Claims (1)

[Claims] The same 161 layer and three or more opposing electrodes with the same gap are arranged at equal intervals on the same circumference.
N! Partially immersed in the I fluid, each one of three or more multiphase signals modulated by one phase of the two-phase signals and having a different frequency from the two-phase signal is applied to one plate of the counter electrode. phase, or by alternately applying one phase of the two-phase 4rJ signal and a multi-phase signal, the signal type 11 generated at the common connection point of the other horizontal plate of the counter electrode is The phase signal component is
The other phase of the phase signal is compared with the voltage obtained by applying it to j, 4 quasi-capacitance, and the voltage corresponding to the change in the total capacitance of the #2 counter electrode is determined at 141. In addition to obtaining a signal related to the surface level, the level of the multiphase signal component of the signal voltage generated at the common connection point is detected, as well as the phase difference of this component from the reference signal. 1I131L for the direction and angle of inclination of the liquid level.
, capacitive type 3 formula to obtain a signal%