CN103528642B - The capacitance level gauge of a kind of real-time correction dielectric constant and level measuring method thereof - Google Patents

Abstract

The present invention discloses capacitance liquid level meter and the level measuring method thereof of a kind of real-time correction dielectric constant, and this liquid level gauge includes outer tube, inner tube, two shading rings and controller；Its middle external tube forms by liquid level outer tube and by the most coaxially connected gas phase outer tube at liquid level outer tube two ends of shading ring and liquid phase outer tube；It is consequently formed three capacitance sensors, is positioned at the liquid phase dielectric constant sensor of bottom, be used for measuring in real time the dielectric constant of liquid phase medium；It is positioned at the gas phase dielectric constant sensor on top, is used for measuring in real time the dielectric constant of gas phase media.During Real-time Liquid Level Measurement, the liquid phase dielectric constant sensor in bottom can converse the dielectric constant of this moment fluid to be measured；Gas phase dielectric constant sensor on top can converse the dielectric constant of this moment liquid overhead gas.Calculated by the true dielectric constant of gas phase liquid phase again and can obtain real liquid level, eliminate because the ambient influnences such as temperature, pressure change dielectric constant, the impact on level gauging.

Description

The capacitance level gauge of a kind of real-time correction dielectric constant and level measuring method thereof

Technical field

Invention relates to a kind of capacitance level gauge and level measuring method thereof, is specifically related to the electric capacity of a kind of real-time correction dielectric constant Formula liquid level gauge and level measuring method thereof, belong to space flight special sensor fields of measurement.

Background technology

Filling the cryogenic liquid in Cryogenic tank, in discharge process, liquid level is extremely important parameter, it is therefore desirable to Liquid level is detected in real time.Conventional low temperature level measuring method is capacitance liquid level measuring method, and capacitance liquid level meter utilizes dielectric Constant difference under liquid and gaseous state detects liquid level.But the dielectric constant of medium is by environmental factors such as temperature and pressures Impact relatively big, directly affect the precision of level gauging, measurement result need to be carried out error correction.

In conventional error correcting method, main utilization look-up table and computing formula revise temperature and pressure to dielectric constant Impact, but be simultaneously introduced the measure error of temperature, pressure, and can not eliminate other environmental factors may impact.

Summary of the invention

In view of this, the present invention provides a kind of capacitance liquid level meter and level measuring method thereof that can revise dielectric constant in real time, energy The measure error that enough dielectric constants of correction in real time bring, improves sensor accuracy.

The described capacitance level gauge revising dielectric constant in real time includes: outer tube, inner tube, two shading rings and controller, outward Peripheral equipment is Cryogenic tank；Described outer tube is by liquid level outer tube and by the most coaxially connected gas phase at liquid level outer tube two ends of shading ring Outer tube and liquid phase outer tube composition；In described outer tube coaxial package inner tube, and and inner tube between have gap.Described gas phase outer tube, Two or more through hole is distributed on the outer circumference surface of inner tube, liquid level outer tube and liquid phase outer tube.Described gas phase outer tube and inner tube coordinate shape Become gas phase dielectric constant sensor；Liquid phase outer tube and inner tube cooperatively form liquid phase dielectric constant sensor；Liquid level outer tube and inner tube are joined Close and form BL.The length of described outer tube when should ensure that use described gas phase outer tube be positioned at the upper cover of Cryogenic tank In, described liquid phase outer tube is positioned at the low head of Cryogenic tank.

Described controller includes: driver, three amplifiers, three a/d converter, sine-wave generator, microprocessors and post Storage；Described sine-wave generator is connected with inner tube by driver.Described gas phase outer tube, liquid level outer tube and liquid phase outer tube are each logical Cross an amplifier and a/d converter is connected with microprocessor；Described register interconnects with microprocessor, stores in register State the calibration data that three sensors record in calibration medium.

Described gas phase outer tube, inner tube, liquid level outer tube and liquid phase outer tube be wall thickness be aluminium-alloy pipe or the stainless steel tube of 3mm-5mm.

Described gas phase outer tube is identical with the physical dimension of liquid phase outer tube.

The level measuring method of above-mentioned capacitance level gauge is:

Step one: before using this capacitance level gauge first, calibrates described capacitance level gauge in calibration medium, obtains Calibration data:

Described capacitance level gauge is vertically placed in calibration medium, starts sine-wave generator output sinusoidal excitation signal； Feedback signal is sent respectively to corresponding amplifier by described three sensors；The described amplifier feedback signal to receiving Amplitude be modulated and amplify, be then sent to corresponding a/d converter；The signal that described a/d converter will receive It is sent to microprocessor after being converted into data signal；Described microprocessor uses following formula according to the three groups of data signals received Calculate calibration data, and calculated calibration data is prestored in a register.

Wherein:For the measurement voltage corresponding to liquid phase dielectric constant sensor electric capacity in calibration medium；

For the measurement voltage corresponding to gas phase dielectric constant sensor electric capacity in calibration medium；

For the measurement voltage corresponding to level gauging capacitance sensor electric capacity in calibration medium；

R_igAnd R_gpFor calibration data.

Step 2: be arranged in Cryogenic tank to be measured by described capacitance level gauge, makes the axis of said inner tube store with low temperature The dead in line of case, and gas phase outer tube is positioned at the upper cover of Cryogenic tank, described liquid phase outer tube is positioned at the low head of Cryogenic tank In.

Step 3: provide sinusoidal excitation signal, described three sensors to formed three sensor by sine-wave generator Feedback signal is sent respectively to corresponding amplifier；The amplitude of the described amplifier feedback signal to receiving is modulated And amplify, it is then sent to corresponding a/d converter；The signal received is converted into data signal by described a/d converter After be sent to microprocessor.

Step 4: prestore zero-bit threshold value and the full scale threshold value of Cryogenic tank in described microprocessor, if BL Feedback signal is zero-bit threshold value, then show that now BL is the most liquid-immersed, and the current level of Cryogenic tank is positioned at Below lower liquid level；

If the feedback signal of BL is full scale threshold value, then show that now BL is totally submerged by liquid, The current level of Cryogenic tank is positioned at more than liquid level；

If the feedback signal of BL is between zero-bit threshold value and full scale threshold value, the most described microprocessor is according to receiving Three data signals and the calibration data that prestores in a register calculate current level by following formula；

Current level is utilized to account for ratio f of the total liquid level of Cryogenic tank to represent current level:

$f=\frac{R_{1g}(V_{gref}-R_{gp}{V}_{probs})}{R_{1g}{V}_{gref}-V_{lref}}$

Wherein: the value of f is from 0 to 1, f is the lower liquid level of 0 corresponding Cryogenic tank, and f is the upper liquid level of 1 corresponding Cryogenic tank； V_grefFor the measurement voltage corresponding to gas phase dielectric constant sensor capacitance present；V_lrefThe most electric for liquid phase dielectric constant sensor Measurement voltage corresponding to appearance；V_probeFor the measurement voltage corresponding to level gauging capacitance sensor capacitance present.

During filling cryogenic liquid in described Cryogenic tank, when described cryogenic liquid did not had liquid phase dielectric constant sensor, The feedback signal sudden change of liquid phase dielectric constant sensor, microprocessor provides lower liquid level warning according to the feedback signal received；When When described cryogenic liquid did not had gas phase dielectric constant sensor, the feedback signal sudden change of gas phase dielectric constant sensor, microprocessor Liquid level warning is given according to the feedback signal received；

During described Cryogenic tank outwards discharges cryogenic liquid, when described gas phase dielectric constant sensor exposes cryogenic liquid, The feedback signal sudden change of gas phase dielectric constant sensor, microprocessor provides liquid level warning according to the feedback signal received；When When described liquid phase dielectric constant sensor exposes cryogenic liquid, the feedback signal sudden change of liquid phase dielectric constant sensor, microprocessor Lower liquid level warning is given according to the feedback signal received.

Described calibration medium is air.

Beneficial effect:

(1) this liquid level gauge is respectively provided with gas phase outer tube and liquid phase outer tube at the two ends up and down of liquid level outer tube, thus coordinates shape with inner tube Become gas phase dielectric constant sensor and liquid phase dielectric constant sensor；It is positioned at the liquid phase dielectric constant sensor structure chi of low head Very little fixing, the dielectric constant of this moment fluid to be measured can be conversed by it；The gas phase dielectric constant being positioned at upper cover passes Sensor physical dimension is fixed, and can pass through its dielectric constant conversing this moment liquid overhead gas.Thus by gas phase liquid phase True dielectric constant calculate and can obtain real liquid level, eliminate because the ambient influnence such as temperature, pressure changes dielectric constant pair The impact of level gauging.

(2) aluminium-alloy pipe is used to make outer tube and the inner tube of liquid level gauge, it is possible to make liquid level gauge have higher stability, it is ensured that to survey The degree of accuracy of amount.

(3) gas phase outer tube and liquid phase outer tube are designed as identical size, it is simple to the calculating of correction data.

(4) described gas phase dielectric constant sensor and liquid phase dielectric constant sensor can carry out the warning of upper and lower liquid level.

Accompanying drawing explanation

Fig. 1 is the scheme of installation of described capacitance liquid level meter.

Fig. 2 is the structural representation of controller.

Wherein, 1-flange, outside 2-gas phase outer tube, 3-shading ring A, 4-inner tube, 5-liquid level outer tube, 6-shading ring B, 7-liquid phase Pipe, 8-Cryogenic tank, 9-upper cover, 10-low head

Detailed description of the invention

Develop simultaneously embodiment below in conjunction with the accompanying drawings, describes the present invention.

The present embodiment provides a kind of capacitance level gauge and level measuring method thereof that can revise dielectric constant in real time, it is possible to surveying The measure error that during amount, real-time modifying factor dielectric constant brings, improves certainty of measurement；And measurement result can be shown intuitively, Without carrying out error correction again.

Described capacitance level gauge includes gas phase outer tube 2, inner tube 4, liquid level outer tube 5, liquid phase outer tube 7, two shading rings and controls Device processed, ancillary equipment is Cryogenic tank 8, as shown in Figure 1.

As a example by attitude when liquid level gauge described in Fig. 1 uses, the openend of Cryogenic tank 8 is considered as top, Cryogenic tank 8 Inside there is superposed gas phase media and be positioned at the liquid phase medium of bottom.Outside the bottom of liquid level outer tube 5 is by shading ring B and liquid phase Pipe 7 is coaxially connected, is consequently formed liquid level gauge outer tube.Convenient for subsequent calculations, gas phase outer tube 2 and liquid level outer tube in the present embodiment 5 equivalently-sized.In liquid level gauge outer tube coaxial package inner tube 4, and and inner tube 4 between have the gap of 2mm.Described liquid level Meter outer tube and inner tube 4 are arranged in Cryogenic tank 8 by the flange 1 of Cryogenic tank 8 opening part, make liquid level gauge outer tube and inner tube The axis of 4 and the dead in line of Cryogenic tank 8.Should ensure that described gas phase outer tube 2 is positioned at the upper cover 9 of Cryogenic tank 8 simultaneously In, liquid phase outer tube 7 is positioned at the low head 10 of Cryogenic tank 8.

For ensureing the degree of accuracy measured, liquid level gauge to have the highest stability, and therefore in the present embodiment, liquid level gauge outer tube uses Aluminium-alloy pipe thick for 5mm is made, and inner tube 4 uses aluminium-alloy pipe thick for 3mm to make.For making liquid level gauge outer tube and inner tube 4 shape The liquid level of the sleeve inner become and liquid level highly consistent, at described gas phase outer tube 2, inner tube 4, liquid level outer tube in Cryogenic tank 8 5 and liquid phase outer tube 7 outer circumference surface on be evenly distributed with some apertures.

In said structure, gas phase outer tube 2 and inner tube 4 cooperatively form gas phase dielectric constant sensor, are used for measuring gas phase in real time and are situated between The dielectric constant of matter；Liquid phase outer tube 7 and inner tube 4 cooperatively form liquid phase dielectric constant sensor, are used for measuring liquid phase medium in real time Liquid phase dielectric constant；Liquid level outer tube 5 and inner tube 4 cooperatively form BL.

The structure of controller as in figure 2 it is shown, include driver, three amplifiers, three a/d converter, sine-wave generator, Microprocessor, register and display.Wherein driver is by driving line to be connected with inner tube 4, for giving three electric capacity formed Sensor provides sinusoidal excitation signal (voltage signal).Gas phase outer tube 2, liquid level outer tube 5 and liquid phase outer tube 7 are respectively put by one Big device and a/d converter are connected with microprocessor, for feedback signal amplification being processed and being sent to microprocessor after AD conversion. In described register, storage has described three sensors to record calibration data in calibration medium.Microprocessor is according to this calibration data And the magnitude of voltage of the three groups of sensor feedback received, calculate the current level of Cryogenic tank 8.

The method using this liquid level gauge to carry out level gauging is:

(1) before using this capacitance level gauge first, it need to be carried out calibration operation, obtain calibration data.The present embodiment Alignment medium selects air, and the computational methods of calibration data are:

Described capacitance level gauge is vertically placed in calibration medium, starts sine-wave generator output sinusoidal excitation signal, just String pumping signal is voltage signal；Feedback signal (voltage signal) is sent respectively to corresponding putting by described three sensors Big device；The amplitude of the described amplifier feedback signal to receiving is modulated and amplifies, and is then sent to corresponding AD Converter；Described a/d converter is sent to microprocessor after the signal received is converted into data signal；Described microprocessor Use following formula (1) to calculate calibration data according to three data signals received, and calculated calibration data is prestored In a register.

Wherein:For the measurement voltage corresponding to liquid phase dielectric constant sensor electric capacity in calibration medium；

For the measurement voltage corresponding to gas phase dielectric constant sensor electric capacity in calibration medium；

For the measurement voltage corresponding to BL electric capacity in calibration medium；

R_lgAnd R_gpFor calibration data.

(2), when using, described capacitance level gauge is arranged in Cryogenic tank 8 shown in Fig. 1, makes described gas phase outer tube 2 upper covers 9 being positioned at Cryogenic tank 8, liquid phase outer tube 7 is positioned at the low head 10 of Cryogenic tank 8, and said two every Concordant with the weld of Cryogenic tank 8 can body with upper cover 9 and low head 10 respectively from ring.Wherein upper cover 9 with can body is The upper liquid level of weld Cryogenic tank 8, the lower liquid level of the weld Cryogenic tank 8 that low head 10 and can body are.By sine wave Generator provides sinusoidal excitation signal (voltage signal) to three sensors formed.

(3) described three amplifiers receive the feedback signal (voltage signal) of respective sensor therewith respectively, and to receiving The amplitude of feedback signal is modulated and amplifies, then is converted into data signal is sent to microprocessor by AD conversion.

(4) microprocessor prestores zero-bit threshold value and the full scale threshold value of Cryogenic tank, if the feedback signal of BL For zero-bit threshold value, then show that now BL is the most liquid-immersed, the current level of Cryogenic tank be positioned at lower liquid level with Under；

If the feedback signal of BL is full scale threshold value, then show that now BL is totally submerged by liquid, The current level of Cryogenic tank is positioned at more than liquid level；

If the feedback signal of BL is between zero-bit threshold value and full scale threshold value, the most described microprocessor is according to receiving Three data signals and the calibration data that prestores in a register calculate current level by following formula.Foundation in the present embodiment Current level accounts for ratio f of the total liquid level of Cryogenic tank to represent current level:

$f=\frac{R_{1g}(V_{gref}-R_{gp}{V}_{probe})}{R_{1g}{V}_{gref}-V_{lref}}---\left(2\right)$

Wherein: the value of f is (0,1)；

V_grefFor the measurement voltage corresponding to gas phase dielectric constant sensor capacitance present；

V_lrefFor the measurement voltage corresponding to liquid phase dielectric constant sensor capacitance present；

V_probeFor the measurement voltage corresponding to level gauging capacitance sensor capacitance present.

The derivation of above-mentioned formula (1) and (2) is:

Described gas phase dielectric constant sensor, BL and liquid phase dielectric constant sensor are capacitance sensor, its The computing formula of capacitance is:

$\left\{\begin{array}{c}{C}_{probe}=K_p\[{\mathrm{\ϵ}}_{l}f+{\mathrm{\ϵ}}_g(1-f)\]\\ C_{lref}=K_l{\mathrm{\ϵ}}_l\\ C_{gref}=K_g{\mathrm{\ϵ}}_g\end{array}\right.---\left(3\right)$

Wherein C_probeCapacitance for BL；C_lrefCapacitance for liquid phase dielectric constant sensor；C_grefFor The capacitance of gas phase dielectric constant sensor；K_pMechanical index for BL；K_lSense for liquid phase dielectric constant The mechanical index of device；K_gMechanical index for gas phase dielectric constant sensor；ε_lFor liquid dielectric constant；ε_gIt is for gaseous state dielectric Constant.

Then current level accounts for the ratio f of total liquid level and is:

$f=\frac{K_l(C_{gref}{K}_p-C_{probe}{K}_g)}{K_p(C_{gref}{K}_l-C_{lref}{K}_g)}---\left(4\right)$

Relation between magnitude of voltage V and its capacitance C of known capacitance sensor output is:Wherein G is that electric capacity passes The gain coefficient of sensor；Then have:

$\left\{\begin{array}{c}{C}_{probe}=\frac{V_{probe}}{G_p}\\ C_{lref}=\frac{V_{lref}}{G_l}\\ G_{gref}=\frac{V_{gref}}{G_g}\end{array}\right.---\left(5\right)$

Wherein: V_probe、C_probeIt is respectively measurement voltage and the capacitance of BL；V_lref、C_lrefIt is respectively liquid phase The measurement voltage of dielectric constant sensor and capacitance；V_gref、C_grefBe respectively gas phase dielectric constant sensor measurement voltage and Capacitance；G_pGain coefficient for BL；G_lGain coefficient for liquid phase dielectric constant sensor；G_gFor gas The gain coefficient of liquid phase dielectric constant sensor.

Bring formula (5) into formula (4) then to have:

$f=\frac{G_l{K}_l(G_p{K}_p{V}_{gref}-G_g{K}_g{V}_{probe})}{G_p{K}_p(G_l{K}_l{V}_{gref}-G_g{K}_g{V}_{lref})}---\left(6\right)$

Formula (6) can be equivalent to:

$f=\frac{\frac{G_l{K}_l}{G_g{K}_g}(V_{gref}-\frac{G_g{K}_g}{G_p{K}_p}{V}_{probe})}{\frac{G_l{K}_l}{G_g{K}_g}{V}_{gref}-V_{lref}}---\left(7\right)$

OrderThen

When capacitor sensor structure size is fixed, R_lgAnd R_gpFor fixed value, therefore by R_lgAnd R_gpAs calibration data；Make Before this liquid level gauge, first calculating this calibration data, then the magnitude of voltage of three sensor outputs being substituted into formula (7) just can be direct Obtain required f value.

The preparation method of calibration data is: whole fluid level measuring gauge is placed on calibration medium in (the calibration medium in the present embodiment is Air), then there is ε_l=ε_g=ε_air.Then BL, liquid phase dielectric constant sensor, gas phase dielectric constant sensing The computing formula of three sensor capacitance values of device is:

Relation between magnitude of voltage and electric capacity and the gain coefficient of above three sensor capacitance sensor output is:

From three above equation, can obtain:

Described controller can also be given according to the feedback signal of gas phase dielectric constant sensor and liquid phase dielectric constant sensor up and down Liquid level warning:

During filling cryogenic liquid in described Cryogenic tank (8), when described cryogenic liquid did not had liquid phase dielectric constant to sense During device, the feedback signal sudden change of liquid phase dielectric constant sensor, microprocessor provides lower liquid level report according to the feedback signal received Alert；When described cryogenic liquid did not had gas phase dielectric constant sensor, the feedback signal sudden change of gas phase dielectric constant sensor, micro- Processor provides liquid level warning according to the feedback signal received.

During described Cryogenic tank (8) outwards discharge cryogenic liquid, when described gas phase dielectric constant sensor exposes Low Temperature Liquid During body, the feedback signal sudden change of gas phase dielectric constant sensor, microprocessor provides liquid level report according to the feedback signal received Alert；When described liquid phase dielectric constant sensor exposes cryogenic liquid, the feedback signal sudden change of liquid phase dielectric constant sensor, micro- Processor provides lower liquid level warning according to the feedback signal received.

In sum, these are only presently preferred embodiments of the present invention, be not intended to limit protection scope of the present invention.All Within the spirit and principles in the present invention, any modification, equivalent substitution and improvement etc. made, should be included in the protection of the present invention Within the scope of.

Claims (4)

1. the capacitance level gauge of a real-time correction dielectric constant, it is characterised in that including: outer tube, inner tube (4), two Individual shading ring and controller, ancillary equipment is Cryogenic tank (8)；Described outer tube by liquid level outer tube (5) and is divided by shading ring The most coaxially connected gas phase outer tube (2) at liquid level outer tube (5) two ends and liquid phase outer tube (7) composition；At described outer tube Coaxial package inner tube (4), and and inner tube (4) between have gap；At described gas phase outer tube (2), inner tube (4), liquid level outer tube (5) and two or more through hole is distributed on the outer circumference surface of liquid phase outer tube (7)；Described gas phase outer tube (2) and inner tube (4) Cooperatively form gas phase dielectric constant sensor；Liquid phase outer tube (7) and inner tube (4) cooperatively form liquid phase dielectric constant sensor； Liquid level outer tube (5) and inner tube (4) cooperatively form BL；The length of described outer tube should ensure that described gas during use Phase outer tube (2) is positioned at the upper cover of Cryogenic tank (8), and described liquid phase outer tube (7) is positioned at the lower envelope of Cryogenic tank (8) In head；

Described controller includes: driver, three amplifiers, three a/d converter, sine-wave generator, microprocessor and Register；Described sine-wave generator is connected with inner tube (4) by driver；Described gas phase outer tube (2), liquid level outer tube (5) Respectively it is connected with microprocessor by an amplifier and a/d converter with liquid phase outer tube (7)；Described register is mutual with microprocessor Even, in register, storage has the calibration data that described three sensors record in calibration medium；

Described gas phase outer tube (2), inner tube (4), liquid level outer tube (5) and liquid phase outer tube (7) be wall thickness be the aluminium of 3mm-5mm Compo pipe or stainless steel tube；

The level measuring method of capacitance level gauge, concretely comprises the following steps:

Step one: before using this capacitance level gauge first, calibrates described capacitance level gauge in calibration medium, obtains Calibration data:

Described capacitance level gauge is vertically placed in calibration medium, starts sine-wave generator output sinusoidal excitation signal；Institute State three sensors and feedback signal is sent respectively to corresponding amplifier；The described amplifier feedback signal to receiving Amplitude is modulated and amplifies, and is then sent to corresponding a/d converter；The signal received is turned by described a/d converter It is sent to microprocessor after changing data signal into；Described microprocessor uses following formula meter according to the three groups of data signals received Calculate calibration data, and calculated calibration data is prestored in a register；

Wherein:For the measurement voltage corresponding to liquid phase dielectric constant sensor electric capacity in calibration medium；

For the measurement voltage corresponding to gas phase dielectric constant sensor electric capacity in calibration medium；

For the measurement voltage corresponding to level gauging capacitance sensor electric capacity in calibration medium；

R_1gAnd R_gpFor calibration data；

Step 2: described capacitance level gauge is arranged in Cryogenic tank (8) to be measured, makes the axle of said inner tube (4) The dead in line of line and Cryogenic tank (8), and gas phase outer tube (2) is positioned at the upper cover of Cryogenic tank (8), described liquid Phase outer tube (7) is positioned at the low head of Cryogenic tank (8)；

Step 3: provide sinusoidal excitation signal, described three sensors to formed three sensor by sine-wave generator Feedback signal is sent respectively to corresponding amplifier；The amplitude of the described amplifier feedback signal to receiving is modulated And amplify, it is then sent to corresponding a/d converter；The signal received is converted into data signal by described a/d converter After be sent to microprocessor；

Step 4: prestore zero-bit threshold value and the full scale threshold value of Cryogenic tank (8) in described microprocessor, if level gauging passes The feedback signal of sensor is zero-bit threshold value, then show that now BL is the most liquid-immersed, Cryogenic tank (8) Current level is positioned at below lower liquid level；

If the feedback signal of BL is full scale threshold value, then show that now BL is soaked completely by liquid Not yet, the current level of Cryogenic tank (8) is positioned at more than liquid level；

If the feedback signal of BL is between zero-bit threshold value and full scale threshold value, the most described microprocessor is according to receiving Three data signals and the calibration data that prestores in a register calculate current level by following formula；

Current level is utilized to account for ratio f of the total liquid level of Cryogenic tank (8) to represent current level:

$f=\frac{R_{1g}(V_{gref}-R_{gp}{V}_{probs})}{R_{1g}{V}_{gref}-V_{lref}}---\left(3\right)$

Wherein: the value of f is (0,1)；V_grefFor the measurement voltage corresponding to gas phase dielectric constant sensor capacitance present；V_lref For the measurement voltage corresponding to liquid phase dielectric constant sensor capacitance present；V_probsFor level gauging capacitance sensor capacitance present Corresponding measurement voltage；

Described gas phase outer tube (2), inner tube (4), liquid level outer tube (5) and liquid phase outer tube (7) be wall thickness be the aluminium of 3mm-5mm Compo pipe or stainless steel tube.

2. the capacitance level gauge revising dielectric constant in real time as claimed in claim 1, it is characterised in that outside described gas phase Pipe (2) is identical with the physical dimension of liquid phase outer tube (7).

3. the capacitance level gauge revising dielectric constant in real time as claimed in claim 1, it is characterised in that:

During filling cryogenic liquid in described Cryogenic tank (8), when described cryogenic liquid did not had liquid phase dielectric constant to pass During sensor, the feedback signal sudden change of liquid phase dielectric constant sensor, microprocessor provides lower liquid level according to the feedback signal received Report to the police；When described cryogenic liquid did not had gas phase dielectric constant sensor, the feedback signal sudden change of gas phase dielectric constant sensor, Microprocessor provides liquid level warning according to the feedback signal received；

During described Cryogenic tank (8) outwards discharge cryogenic liquid, when described gas phase dielectric constant sensor exposes low temperature During liquid, the feedback signal sudden change of gas phase dielectric constant sensor, microprocessor provides liquid level according to the feedback signal received Report to the police；When described liquid phase dielectric constant sensor exposes cryogenic liquid, the feedback signal sudden change of liquid phase dielectric constant sensor, Microprocessor provides lower liquid level warning according to the feedback signal received.

4. the capacitance level gauge revising dielectric constant in real time as claimed in claim 1, it is characterised in that: described calibration is situated between Matter is air.