CN1910462A

CN1910462A - Method and apparatus for measuring electrical conductivity

Info

Publication number: CN1910462A
Application number: CN 200580002644
Authority: CN
Inventors: A·D·马克斯韦尔; A·L·阿福克; N·H·汉考克
Original assignee: University of Southern Queensland
Current assignee: University of Southern Queensland
Priority date: 2004-01-15
Filing date: 2005-01-14
Publication date: 2007-02-07
Anticipated expiration: 2025-01-14
Also published as: CN100472218C

Abstract

An apparatus (12) for measuring electrical conductivity in a material comprises a pair of electrically conducting elements (6), a first electrical conductor (9) coupled to the electrically conducting elements, the first electrical conductor coupling a first transformer core (10) and a second transformer core (12) to form a first current loop (8) and a second electrical conductor (17) of known resistance coupling the second transformer core and a third transformer core (14) to form a second current loop (16).

Description

Be used to measure the method and apparatus of conductivity

Technical field

The present invention relates to a kind of method and apparatus that is used to measure conductivity, especially the measurement in having the material of low conductivity.Especially, though be not unique, the present invention relates to be used for measuring the method and apparatus of conductivity at low conductivity bulk material (bulk material).But method and apparatus of the present invention also can be used to have the material of high conductivity.

Background technology

All need accurately measure the ability of conductivity in much different fields in bulk material, this ability is essential for measure conductivity in having the material of low conductivity especially.An example is food industry, wherein measures conductivity to determine and/or to check the characteristic of food.For example, adopted the technology of measuring the milk conductivity increasing with bacterium in the physical chemistry of checking milk and the milk.McPhillips, J.﹠amp; Snow, N. (1958); " Studies on Milk with a New Type ofConductivity Cell "; The Australian Journal of Dairy Technology 192-196 page or leaf; disclose a kind of electronic installation; be used to carry out the measurement of relevant milk, and Gupt a, S.﹠amp; G. (1956), " A Precision Electrode-less Conductance Cell foruse at Audio Frequencies " a kind of similar electronic installation disclosed.Two kinds of layouts include by toroid transformer and are coupling in current return between exciting circuit and the sensor circuit.

But these layouts all are unsuitable for being used in the various application occasions, the application scenario in the drum for example, because measured material can pollute and the blocking current loop, when drum must be cleared up, it further caused problem.

These arrange that another problem that is had is that they can bear power supply excitation fluctuation, and this causes measuring noise, and needs stabilized power source and monitoring supply voltage.

Therefore, need be used for accurately measuring system and/or the method and/or the equipment of conductivity, it can solve or improve the problems referred to above at least.Especially, need this system, method and/or equipment are used to measure the conductivity of material of low conductivity.

In this manual, term " comprises " that " comprising " or similar terms are used to represent nonrestrictive comprising, and for example comprises the method for a series of elements, and system or equipment does not comprise those elements individually, also comprises the element that other is not listed.

Summary of the invention

On the one hand, though it needs not be unique or in fact the most wide in range form, the invention reside in a kind of equipment that is used for measuring at material conductivity, described equipment comprises:

The pair of conductive element;

Be coupled to first electric conductor of described conducting element, described first electric conductor is coupled first transformer core and second transformer core to form first current return; With

Second electric conductor with known resistance is coupled described second transformer core and the 3rd transformer core to form second current return.

Suitably, described conducting element is bolt or stopper form.As selection, described conducting element is plate or loop type.

Suitably, described first, second and the 3rd transformer core are ring-type " C ", " O " or " E " deformation depressor iron core or its combination.

Suitably, described first, second and the 3rd transformer core are FERRITE CORE, laminated core or dust core or its combination.

Preferably, this equipment also comprises at least one installing plate, and described conducting element is attached on the installing plate, and described at least one installing plate is attached on the described container of material.

Suitably, described second current return is partly by being attached on described at least one installing plate, and forms with the becket of described conducting element electric coupling, and described becket supports described first and second transformer cores.

According to an embodiment, described first, second is ring-type " O " the deformation depressor iron core that links to each other with described becket with the 3rd transformer core, makes that the axis of transformer core is orthogonal.

On the other hand, the invention reside in the method for measuring conductivity in material, described method comprises the following steps:

The pair of conductive element is installed to contact with described material;

The be coupled described pair of conductive element and first electric conductor, described first electric conductor are coupled first transformer core and second transformer core to form first current return;

Described second transformer core and the 3rd transformer core are coupled to form second current return with second electric conductor with known resistance;

Measure the voltage of crossing over described material and described first transformer core;

By measuring the reference voltage of crossing over described the 3rd transformer core, the driving voltage of described second transformer core is crossed in monitoring; With

From crossing over the described voltage of described material, described reference voltage and described known resistance are determined the described conductivity of described material.

As selection, the described conductivity of described material is from determining with the corresponding current measurement of described voltage measurement.

According to following detailed description, further feature of the present invention will become apparent.

Description of drawings

In order to help to understand the present invention and those skilled in the art realize the present invention, the preferred embodiments of the present invention explanation by way of example with reference to the accompanying drawings, wherein:

Fig. 1 is according to one embodiment of the invention, is used for measuring at material the equipment synoptic diagram of conductivity;

Fig. 2 is the alternative view of equipment shown in Fig. 1, represents the actual arrangement of this part of appliance;

Fig. 3 is the synoptic diagram of equipment second embodiment among Fig. 1 and 2;

Fig. 4 is an installing plate, the planimetric map of stationary installation and half current return;

Fig. 5 is the partial enlarged drawing of Fig. 4;

Fig. 6 represents first, second and the 3rd transformer core, first current return and half current return;

Fig. 7 represents voltage ratio and the uncorrected curve of Klorvess Liquid volumetric molar concentration;

Fig. 8 represents the curve of voltage ratio and the correction of Klorvess Liquid volumetric molar concentration;

Fig. 9 represents voltage ratio and the uncorrected curve of the theoretical conductivity of Klorvess Liquid;

Figure 10 represents the curve of voltage ratio and the theoretical conductivity correction of Klorvess Liquid;

Figure 11 represents the details of conducting element spacing according to the preferred embodiment of the invention;

Figure 12 represents the relation between installing plate preferred size and the conducting element;

Figure 13 represents the cross-sectional elevational view of conducting element embodiment;

Figure 13 A represents the planimetric map of Figure 13 conducting element;

Figure 14 represents other details of Figure 13 conducting element;

Figure 15 is the planimetric map of installing plate and Figure 14 conducting element and loop alternate embodiment;

Figure 16 is the front view of embodiment shown in Figure 15;

Alternate embodiment shown in Figure 17 presentation graphs 1;

Alternate embodiment shown in Figure 18 presentation graphs 2;

Alternate embodiment shown in Figure 19 presentation graphs 3;

Figure 20 is one embodiment of the invention is applied to measure material electric conductivity in pipeline a skeleton view;

Figure 21 is the alternate embodiment shown in Figure 20;

Figure 22 is the planimetric map of embodiment shown in Figure 20; And

Figure 23 is another alternate embodiment shown in Figure 20.

Embodiment

With reference to Fig. 1 and 2, provide a kind of being used for accurately to measure conductivity, in particular in having the bulk material of low conductivity, measuring the equipment 2 of conductivity at material.Equipment 2 comprises a container, and this container adopts the form of the liquid unit 4 of holding material, and material is the form of liquid 5 in this embodiment.Liquid unit 4 is constructed in the mode identical with the standard conductivity measuring unit, and comprises the pair of conductive element, and this adopts the form of a pair of plate 6 to conducting element, is arranged to contact with liquid 5.The structure of liquid unit 4 is common for those skilled in the art among this embodiment.

Equipment 2 comprises that also first current return, 8, the first electric conductors that formed by first electric conductor adopt the form of first lead 9 that passes first transformer core 10 and second transformer core 12.Provide the 3rd transformer core 14 to be used for, and second current return 16 is formed the form that second lead 17 of second transformer core 12 and the 3rd transformer core 14 is passed in the employing of second electric conductor by second electric conductor with reference to monitoring.In one embodiment,

transformer core

10,12,14 adopt ring-type ferrite " C " deformation depressor iron core, but the instead of transformers iron core can adopt the transformer core such as ring-type ferrite " O " or " E " shape.Also can adopt ring-type ferrite " C " shape, the combination of " O " and/or " E " deformation depressor iron core.In alternate embodiment, can adopt laminate transformer iron core or press-powder transformer core.But because ring-type ferrite " O " deformation depressor iron core has improved electromagnetism stability and self-shileding characteristic, the applicant has determined that ring-type ferrite " O " deformation depressor iron core is first-selected, and this has promoted to improve the dynamic usable range of this method and apparatus.

First transformer core 10 is measured the voltage V that crosses over liquid 5 in the liquid unit 4 _Fluid, and second transformer core 12 is for having the excitation iron core of typical driving voltage 10V RMS.Second lead 17 that forms second current return 16 has known resistance R _Standard, and second current return, 16 coupling second transformer core 12 and the 3rd transformer cores 14, but first transformer core, 10, the first transformer cores 10 that are not coupled are used for measuring the voltage V that crosses over liquid unit 4 liquid 5 _FluidInduced voltage depends on the stack that the driving voltage of crossing over second transformer core 12 and the 3rd transformer core 14 are considered the intrinsic monitoring of driving voltage, and this makes above-mentioned noise of the prior art and stability problem minimum.

Liquid 5 is the resistance R between the plate 6 in liquid unit 4 _FluidRepresent with formula 1:

R _Fluid=(R _Standard* V _Fluid)/V _StandardFormula (1)

Liquid resistance R _FluidWith its electricalresistivity _FluidBe directly proportional, and the conductivity of liquid _FluidIt is the inverse of resistivity.Thereby, the conductivity of liquid _FluidWith liquid resistance R _FluidInverse be directly proportional.

The applicant when measuring, determines that the layout of equipment shown in Fig. 1 and 2 has some difficulty in big barrel-like structure.Therefore, the applicant has designed the alternate device that is used for practical application, shown in an alternative embodiment of the invention among Fig. 3.Identical Reference numeral is used to represent feature identical between the embodiment.

In this embodiment, replace liquid unit 4 among the last embodiment, be used for measured container of material and adopt bucket 18 with barrel wall 19.Identical with the material that is used for bucket 18, plate 6 is made by suitable food-grade stainless steel, to avoid producing the thermopair effect.In the embodiment shown in Fig. 3, plate 6 is contained on the installing plate 20, and it is made by PTFE in this embodiment.But, can adopt any other suitable food grade plastic.Should be noted that this layout makes equipment 2 can be installed in barrel wall and other holds on the measured container of material.This being arranged in formed " half current return " 22 between the plate 6, thereby allows non-exciting conductance rate to measure.Installing plate 20 makes plate 6 insulated from each other and make

plate

6 and 19 insulation of bucket wall.

Below with reference to the realization mechanically of Fig. 4-6 this equipment of explanation.

With reference to figure 4, becket 28 is connected on the installing plate 20 by stationary installation, to form above-mentioned half current return 22.In this embodiment, stationary installation adopts the form of pair of bolts 24 and a pair of nut 26.Alternatively, can adopt special stopper or other suitable known stationary installation.Enlarged drawing among Fig. 5 has represented that each nut 26 comprises first screw thread 27 that is arranged on the first direction, and for example, clockwise and layout second screw thread 29 in the opposite direction for example, is counterclockwise in this embodiment.Screw thread 31 directions of bolt 24 and screw thread 33 directions on becket 28 ends are arranged in such a way, and nut 26 is connected on the bolt 24 securely, and becket 28 ends are connected on the nut 26, thereby produce firm electrical connection.The end of bolt 24 and ring 28 is designed so that they nip each other, so that the electric loss minimum by joint between bolt 24 and the becket 28.

Bolt 24 and encircle 28 between low resistance, the reliable connection that is preferably zero resistance can realize in many ways.For example,

screw thread

31,33 can mill and become to have the raised tooth decorative pattern or bossing that other is very little, sharp-pointed, and these bossings are out of shape when fastening nut 26.As an alternative, the end of bolt 24 and ring 28 can be complementary shape, and for example taper and back taper make them be fitted to each other, and connects to produce good conduction.Another kind of replacement scheme can adopt the material of one deck such as beryllium, has with respect to two surfaces, and is very little, the sharp protrusion part.Then this layer filled between the end of

screw thread

31 and 33, so that the interlock effect of expectation to be provided.Beryllium has good interlock performance, and is generally used for this purpose, but may have the shortcoming of the thermopair effect that generation do not expect.

Preferably, bolt 24, nut 26 and becket 28 are made by the stainless steel of same levels, to avoid producing any hot e.m.f..Adopt suitable food-grade stainless steel, its application for food-processing industry is safe and suitable.This stainless use also prevents the pollution of food and the similar pollution that can produce when adopting such as materials such as copper, this can cause the problem such as copper creep and crystal boundary diffusion.

Alternatively, can be provided for encircling 28 additional support so that act on mechanical load minimum on bolt 24 and the installing plate 20.This additional support can adopt pillar, bridging, welding or other supporting form well known in the art, provides insulation completely, to avoid interference current return 28.For this purpose, can adopt appropriate plastic material, PTFE or with the stainless steel of ring 28 contact point place insulation.

Be installed on the ring 28 with reference to figure 6, the first and

second transformer cores

10,12, it forms the part of first current return 8.The 3rd transformer core 14 be can't help to encircle 28 and is supported, and remains on the correct position plastics for example, PTFE or at the stainless steel of contact point place insulation but support by the insulation of any suitable form.Second transformer core 12 and the 3rd transformer core 14 of lead 17 couplings formation second current return 16 that as shown in the figure, resistance is known.

First, second and the 3rd transformer core have x, y and z coil respectively, and wherein roughly numerical value and the scope of x, y and z are as follows: x=100-200, y=20, z=100-200.The coil turn that is adopted depends on the size and the magnetic characteristic of

iron core

10,12,14, the voltage output level of the selected scope of the resistance between electrode that measure and expectation.Along with the increase of coil turn on the iron core, the sensitivity of equipment 2 improves.But the increase of coil turn has also increased electric capacity, resistance and inductance, thus influence low-pass filtering and coil harmonic parameters.

Below with reference to Fig. 3, the detection of 6-8 and table 1 explanation equipment of the present invention and method.

With reference to figure 3 and 6, amplified by high power amplifier 32 by the 30kHz sinusoidal signal that precise frequency signal generator 30 produces, and amplifying signal inputs to second transformer core 12.Liquid voltage V _FluidWith leap the 3rd transformer core 14 voltage V _StandardVoltage ratio V _RatioRepresent with formula 2:

V _Ratio=V _Fluid/ V _StandardFormula (2)

In this embodiment, liquid unit 4 has the capacity of 10L, and has been full of potassium chloride (LCl) solution.By adding the KCl salt of scheduled volume, the volumetric molar concentration of potassium chloride (LCl) solution with predetermined and repeatably mode change.For the solution of each volumetric molar concentration, measure V _FluidAnd V _Standard, the result is as shown in table 1:

Table 1

KCl volumetric molar concentration [M]	The Vref[V that measures]	The Vfluid[V that measures]	Theoretical conductivity [mS/cm]	The ratio Vfluid/Vref that measures	The theoretical correction than (1+1.75Molarity) Ratio
KCl volumetric molar concentration [M]	The Vref[V that measures]	The Vfluid[V that measures]	Theoretical conductivity [mS/cm]	The ratio Vfluid/Vref that measures	The theoretical correction than (1+1.75Molarity) Ratio	0	1.760	0.025	0.119	0.014	0.014
0.01	1.755	0.692	1.408	0.395	0.401	0	1.760	0.025	0.119	0.014	0.014
0.01	1.755	0.692	1.408	0.395	0.401	0.02	1.757	1.318	2.694	0.750	0.776
0.03	1.787	1.929	3.976	1.079	1.136	0.02	1.757	1.318	2.694	0.750	0.776
0.03	1.787	1.929	3.976	1.079	1.136	0.04	1.795	2.495	5.254	1.390	1.487
0.05	1.798	3.049	6.529	1.696	1.844	0.04	1.795	2.495	5.254	1.390	1.487
0.05	1.798	3.049	6.529	1.696	1.844	0.06	1.798	3.577	7.800	1.989	2.198
0.07	1.802	4.080	9.068	2.264	2.542	0.06	1.798	3.577	7.800	1.989	2.198
0.07	1.802	4.080	9.068	2.264	2.542	0.08	1.802	4.558	10.332	2.529	2.884
0.09	1.802	5.030	11.593	2.791	3.231	0.08	1.802	4.558	10.332	2.529	2.884
0.09	1.802	5.030	11.593	2.791	3.231	0.1	1.803	5.544	12.850	3.075	3.613
0.2	1.812	9.388	25.223	5.181	6.994	0.1	1.803	5.544	12.850	3.075	3.613
0.2	1.812	9.388	25.223	5.181	6.994	0.3	1.819	12.389	37.237	6.811	10.387
0.4	1.825	14.797	48.893	8.108	13.784	0.3	1.819	12.389	37.237	6.811	10.387
0.4	1.825	14.797	48.893	8.108	13.784	0.5	1.829	16.798	60.190	9.184	17.220
0.6	1.833	18.472	71.129	10.077	20.659	0.5	1.829	16.798	60.190	9.184	17.220
0.6	1.833	18.472	71.129	10.077	20.659	0.7	1.833	20.090	81.710	10.960	24.386
0.8	1.990	23.330	91.931	11.724	28.137	0.7	1.833	20.090	81.710	10.960	24.386
0.8	1.990	23.330	91.931	11.724	28.137	0.9	1.992	24.467	101.795	12.283	31.628
1	1.993	25.514	111.300	12.802	35.205	0.9	1.992	24.467	101.795	12.283	31.628

Table 1 is also represented the estimation conductivity of KCl solution, it comprises ± and the error of 5mS/cm.Voltage ratio V _RatioWith the curve map of volumetric molar concentration as shown in Figure 7.Nonlinear relationship between voltage ratio and the solution volumetric molar concentration is the additional resistance owing to 2ohms in second current return 16.It is applied the correction factor correction in voltage ratio, and revises voltage ratio shown in right-hand column in the table 1.Revise voltage ratio V _RatioWith the curve map of volumetric molar concentration as shown in Figure 8.Voltage ratio V _RatioWith the curve map of conductivity as shown in Figure 9.Revise voltage ratio V _RatioWith the curve map of conductivity as shown in figure 10.

Fig. 7 and 8 clearly shows and revises in voltage ratio and the liquid unit 4 between the KCl solution volumetric molar concentration dullly, and in the situation of Fig. 8, roughly is linear relation.Equally, Fig. 9 and 10 clearly shows and revises in voltage ratio and the liquid unit 4 between the KCl electrical conductivity of solution dullly, and in the situation of Figure 10, roughly is linear relation.

Fig. 7,8,9 and 10 proves that also equipment of the present invention is suitable for measuring low conductivity in material, and it can also be used to distinguish difference very little between the conductivity.This ability makes it possible to variation very trickle in the test material.Detect this very little variation and represent the variation of material character, not only can be used in the application of related food, but also can be used in other field.

In equipment of the present invention, provide adapter transformer iron core 14 can not only in material of low conductivity, measure conductivity, and make this equipment can handle the fluctuation of crossing over second transformer core, 12 driving voltages, thereby it helps the accuracy that stability helps this measuring equipment.

Other details below with reference to 11 and 12 explanation plates 6 and installing plate 20.By electromagnetic model, the applicant determines the measurement for the milk-based liq conductivity, and the spacing at circular slab 6 centers-center should approximately be between a times to ten times of plate 6 diameters usually, but preferably is between three times to four times of plate 6 diameters.Other the center-center distance that can imagine plate 6 for the measurement of other material electric conductivity with particularly suitable.The applicant determines that also insulating mounting plate 20 should have such size, and promptly its border is three times of plate 6 diameters at least.Therefore, as shown in Figure 11 and 12, for the plate with 40mm diameter, the spacing between its center approximately should be 4 * 40mm-20mm=140mm.Installing plate 20 has the size 300 * 600mm that satisfies above-mentioned second standard.

With reference to Figure 13,13A and 14, the preferred embodiment of plate 6 comprise threaded rod 40 and are welded to the corrosion resistant plate 6 of bar 40 ends.The plate 6 that size is suitable has the diameter of about 40mm and the thickness of about 2-3mm.Plate 6 is recessed in the plastic mounting plate 2, and plastic mounting plate 20 has elastomeric seal, and sealing takes to be arranged in the rubber washer 42 between plate 6 downsides and the installing plate 20.Second packing ring 44 is arranged in installing plate 20 opposite sides and is fixed on the correct position, as shown in Figure 14 with nut 46.

With reference to Figure 15 and 16, the preferred mounting arrangements of ring-

type transformer core

10,12,14 makes its axis orthogonal.This makes the intersection magnetic couple minimum between the iron core, otherwise can reduce the sensitivity of conductivity measurement.According to an embodiment, the mutually perpendicular mounting arrangements of ring-type transformer core realizes that by ring 28 ring 28 comprises two bendings 48 that are in 45 degree.The first driver transformer iron core 10 and the second current sense transformer iron core 12 be through on the ring 28, make they have vertical towards.The 3rd reference current sensor transformer iron core 14 is connected to by any suitable device for mechanical and encircles 28 center section, makes its axis normal in two transformer cores 10,12.In the embodiment shown in Figure 15 and 16, transformer core 14 is connected on the ring 28 by insulating mounting piece 49, and mounting blocks 49 is molded or be processed into iron core 14 and ring 28 are met at right angles.Simple insulation clip or ring, for example plastics sour jujube bar is used for this assembly firmly fixing facing to ring 28.

Second current return 16 is by forming as second lead 17 that passes

transformer core body

12 and 14 that illustrates among the last embodiment.Though can adopt the iron core that substitutes diameter, the typical internal diameter of transformer core and external diameter are respectively 18mm and 45mm.In this case, ring 28 has the thickness of about 15mm, passes to allow

core body

10 and 12, and allows coverture to avoid scraping around encircling the inside surface that twines with protection ring-type iron core.Ring is used to hold the hole 52 of threaded rod 40 in 28 can depart from the ring center line to keep structural strength.

The applicant has determined to adopt the replacement scheme of current measurement as voltage measurement, and has been found that current measurement is to measure conductivity method preferably.With reference to figure 17-19, in first current return 8 and second current return 16, current measurement all realizes by the first and the

3rd transformer core

10,14 with single secondary coil.This layout provides almost 1: 1 electric current, and is consistent with the electric current by primary coil, provides and be used to measure the excitation insulation of the reometer (not shown) of electric current I simultaneously.In the illustrated embodiment, second transformer core has 100 circles, though coil turn is not critical.Single coil in the first and the 3rd transformer core makes the current i maximum of being measured by reometer.

With reference to figure 20-23, the another kind of application of the present invention is to measure conductivity of electrolyte materials in pipeline.Plate 6 is installed on the insulating mounting plate 20, and it occupies the part of pipeline 18 walls 19.First current return 8 is formed by the first electric conductor coupling plate 6 that adopts first lead, 9 forms.This is arranged in and produces " half current return " that allows non-exciting conductance rate to measure between the plate 6, and is illustrated among the embodiment as mentioned.Installing plate 20 make plate 6 insulated from each other and with tube wall 19 insulation.Though expression in Figure 20-23, the layout of metering circuit and transformer core will be with mentioned above identical, and as shown in Figure 19.Depend on the diameter of pipe 18, insulating mounting plate 20 can occupy any part of tube wall 19 circumference.As shown in Figure 20 and 21, depend on the diameter and/or the geometric configuration of pipe 18, plate 6 can be circumferentially or vertically to arrange.

In an alternate embodiment, as shown in figure 23, a plurality of

insulcrete elements

60,61 and 62 that installing plate 20 is had adjacent

conductive element

64,65 replace.In this embodiment, conducting

element

64,65 adopts the form of a pair of electrical insulation ring 64,65.The same with

ring

64,65,

plate

60,61 and 62 extends on the whole circumference of tube wall 19.The layout of " half current return " 22 is as indicated above, has the first electric

conductor coupling ring

64,65 that adopts first lead 9.

Though describe the present invention, be appreciated that the present invention also is suitable for measuring conductivity in the material under being in other state about in the liquid unit that contains KCl solution, measuring conductivity.And though about measure conductivity in having the material of low conductivity equipment of the present invention and method are illustrated, Shuo Ming equipment and method can also be used for accurately measuring conductivity at the material with high conductivity here.

Run through whole instructions target of the present invention has been described, and do not limited the invention in the set of arbitrary embodiment or special characteristic.Those skilled in the relevant art can realize falling into variation in the scope of the invention according to specific embodiment.For example, the size of pair of conductive element 6, shape, area and insulation, and the size of installing plate 20, shape and area can change to realize optimum result.Also can change specific coil winding arrangement, the material of coil turn and employing, and canonical reference resistance value.

Claims

1, a kind of equipment that is used for measuring conductivity at material, described equipment comprises:

The pair of conductive element;

Be coupled to first electric conductor of described conducting element, described first electric conductor is coupled first transformer core and second transformer core to form first current return; And

2, equipment according to claim 1, wherein said conducting element are bolt or stopper or plate.

3, equipment according to claim 1, wherein said first, second and the 3rd transformer core are ring-type " C ", " O " or " E " deformation depressor iron core or its combination.

4, equipment according to claim 1, wherein said first, second and the 3rd transformer core are FERRITE CORE, laminated core or dust core or its combination.

5, equipment according to claim 1 comprises that also at least one is used to install the installing plate of described conducting element, and described at least one installing plate is attached on the described container of material.

6, equipment according to claim 1, wherein said second current return is partly by being attached on the described installing plate, and forms with the becket of described conducting element electric coupling, and described becket supports described first and second transformer cores.

7, equipment according to claim 6, wherein said first, second is coupled on the described becket with the 3rd transformer core, makes that the axis of transformer core is orthogonal.

8, equipment according to claim 1, the spacing at wherein said conducting element center-center are between a times to ten times of described conducting element diameter.

9, equipment according to claim 1, wherein, in order to measure conductivity in milk system liquid, the spacing at described conducting element center-center is between three times to four times of described conducting element diameter.

10, equipment according to claim 5, wherein the border of at least one installing plate is at least three times of described conducting element diameter.

11, equipment according to claim 1, wherein said first transformer core and described the 3rd transformer core include independent secondary coil separately.

12, equipment according to claim 5, wherein said container are pipes, and described at least one installing plate is at least in part along described pipe longitudinal extension, or circumferentially extend around described pipe at least in part.

13, equipment according to claim 12, wherein said conducting element extends on described pipe circumference.

14, equipment according to claim 13 also comprises being positioned near the described conducting element and the insulcrete element that extends on described pipe circumference.

15, a kind of method of measuring conductivity in material, described method comprises the following steps:

The pair of conductive element is installed to contact with described material;

With the coupling of described pair of conductive element and first electric conductor, described first electric conductor is coupled first transformer core and second transformer core to form first current return;

16, a kind of method of measuring conductivity in material, described method comprises the following steps:

The pair of conductive element is installed to contact with described material;

Secondary coil by described first transformer core is measured the electric current that passes through described material;

According to the reference current of measuring by described the 3rd transformer core secondary coil, the driving voltage of described second transformer core is crossed in monitoring; And

From described electric current by described material, described reference current and described known resistance are determined the described conductivity of described material.