DE2643964A1 - METHOD AND DEVICE FOR LOCATING THE SEPARATION LEVEL BETWEEN TWO FLUID PHASES WITH DIFFERENT ELECTRICAL CONDUCTIVITY - Google Patents

Description

ΡΑΤΞΝΤΑΝ RULE

A. GREEN CORNER

OIPt - iMG.

H. KlNKELDEY

Ea-INGL

W. STOCKMAIR

Da-IMG. AnE (CAUEOt

K. SCHUMANN

Often RER NAT. - DlPL- PHYa

P. H. JAKOB

DIFL-ING.

G. BEZOLD

DR RER NAT OIPL-CHEM.

8 MUNICH 22

MAXIMILIANSTRASSE 43

Sept. 29, 1976 PH 10 84-9

COMMISSAEIAT AL ¹ EKERGIE ATOMIQUE

29-33 rue de la Federation Paris (XV) France

Method and device for localizing the separation level between two fluid phases with different electrical conductivity

The invention relates to a method and a device for Locating the level of separation between two fluid phases with different electrical conductivity.

Numerous methods and devices are known with which the separation level between two liquid phases can be measured. In most cases, vertical, dipping into the liquid electrodes and electrical devices are used which allow, the length by which the electrodes 3 ny of the liquids are immersed or to determine the number of electrodes which are located above the separating surface .

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TELEPHONE (OSO) 33 28 62 TELEX OS-SS 3BO TELEGRAMS MONAPTH TELECOPER

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These known methods and devices provide useful results when the liquids determine their level of separation have very different electrical conductivities, but these methods and devices are poor useful when this difference becomes small. In addition, the performance achieved depends on the absolute value of the conductivity of the solutions.

The aim of the invention is a method and a device that allow the separation level between two fluid phases itself to be localized when their electrical conductivities differ only very slightly. The services of the Devices should be relatively independent of the absolute value of these conductivities.

The invention provides a method for localizing the separation level between two liquid-liquid phases or liquid-gas phases supplied with different electrical conductivity, characterized in that a number of identical along the vertical direction distributed electrodes is immersed in the two phases and each with a series of identical resistances is connected, that a common electrode is immersed in both phases, that an electrical Voltage is applied between the common electrode and each pair of electrode resistors that is applied to the terminals of each The voltages appearing in the resistors are measured, these measured voltages having a narrow distribution either an upper value for the electrodes immersed in the phase which has a higher conductivity, or a lower value Value for the electrodes immersed in the phase that has a lower conductivity equal to, and that the number of voltages that equal the upper value or the lower value with a narrow distribution is counted This number indicates the position of the separation level in relation to the number of electrodes.

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This procedure can be carried out in two different ways, but they are not intended to be limiting:

In the first type of implementation, an average voltage is formed which is equal to half the sum of the Voltage of the top electrode and the voltage of the bottom electrode, and this mean voltage becomes linear integrated, the integrated mean voltage is then compared with a fixed reference voltage and becomes the time at which the mean integrated voltage reaches the value of the reference voltage, the number of integrated Counts voltages that have exceeded the reference value. In the second type of implementation, the Terminals of all resistances measured voltages are linearly integrated and the integrated voltages are linked to a reference voltage compared, which has a first value at the beginning, but then when one of the integrated voltages has this reaches first value, assumes a second value which is below the first value by an amount equal to one assumed distribution, which will show the values of the group of higher voltages, and will subsequently be the number of the integrated voltages are counted which have a higher value than the second value of the reference voltage.

The invention also provides a device for implementation of said method, which is characterized by a number of identical ones along the vertical direction electrodes distributed and immersed in the two phases, each connected to a series of identical resistors are, through a common electrode, which is immersed in both phases, through a voltage source, its voltage poles with the common electrode and each pair of electrode resistors are connected by a device for measuring the voltages appearing at the terminals of all resistors, wherein the measured voltages in a narrow distribution either

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an upper value for the electrodes immersed in the phase which has a higher conductivity, or a lower value for the electrodes that are immersed in the phase which has a ^ lower conductivity, equals, and by means of counting the number of voltages which have the upper or lower value in the narrow distribution. The device for counting the number of voltages with the higher value preferably has a reference voltage source, so much Conduction paths such as electrodes, each conduction path having a linear integrator to which the terminals of the resistor of the Electrode tapped voltage is, and has a comparator to which the voltage output by the integrator and the reference voltage is a logical device for counting the number of comparators that are in a particular state find and comprises a control device that provides for the application of the voltage of the voltage source and commands that the State of the comparators is counted by the counter.

The device according to the invention can have two forms, depending on whether one or the other variant of the method is to be carried out. In the first embodiment, an integrator for the mean voltage between the voltage of the uppermost electrode and the voltage of the lowermost electrode and a comparator for comparing this mean voltage with the reference voltage are provided. In the second embodiment, means are provided which decreases the reference voltage from a first value by an amount to a second value which is equal to the assumed distribution which the values of the group of higher voltages show, and means which at the time counts at which the reference voltage is reduced.

In the following , preferred exemplary embodiments of the invention are explained in more detail with reference to the associated drawing:

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Figure 1 shows schematically the inventive arrangement of the Electrode group.

FIG. 2 shows the Spamiungs scatter curves as a function of the ratio compatible with the device the upper to the lower tension.

Figure 3 shows a schematic overview of the Device according to the invention related circuits.

Figure 4- shows a schematic overview of the facility, which can generate an integrated mean voltage in a first embodiment of the invention.

Figure 5 shows a schematic overview of the device, which can lower the reference voltage in a second embodiment of the invention.

FIG. 6 shows a schematic overview of the device for resetting the various elements of the circuit to zero.

In Figure 1, the basic idea of the fiction according to the method is shown. The problem is to locate the level of separation between two liquids' 2 and * k with different electrical conductivity and density. For this purpose, it is provided according to the invention, on the one hand, to immerse a large number of electrodes 6, which are all identical to one another and distributed vertically, and, on the other hand, to immerse a main electrode 8 which is immersed in both solutions 2 and 4. Each of the electrodes 6 is connected to a resistor 10, all resistors associated with the electrodes being identical. A voltage can be applied to the common electrode 8 and the resistors 10 via a voltage source 12, which voltage allows a current to flow in the solutions 2 and 4-. Voltages then appear at the terminals of the resistors 10

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genes that can be tapped and measured. In the following, these voltages are referred to as electrode voltages for the sake of simplicity called.

These voltages are a function of the strength of the current flowing through the resistors, which is itself a function of the Conductivity of the solutions is. For example, if solution 2 has a higher conductivity than solution 4, the Electrode voltages that are tapped at the terminals of those resistors that are assigned to the electrodes that are in the Immerse solution 2, have a higher value than the voltages that are tapped at the terminals of those resistors assigned to electrodes that are immersed in solution 4. Thus, the measured voltages are either equal to a higher voltage V or equal to a lower voltage V-. For a variety of reasons related to the fact stand that the electrodes are not exactly identical, that their surface properties can be different and that the solutions can partially diffuse into one another, especially in the vicinity of their interfaces, are in reality the higher and lower voltages show a certain distribution D, so that the measured voltages are in reality Distribute into two groups of values near the higher voltage V_ and the lower voltage V-.

The method according to the invention now consists in counting the number of voltages in the narrow distribution D one equal to a higher value V, or what comes to the same thing, to count the number of voltages which, in a narrow distribution D, are also equal to a lower value V. This number actually indicates the number of electrodes that are in the solution with the higher or the lower conductivity are immersed and consequently allows the position of the separation level to be determined with respect to the electrode set, which is shown in forms a reference scale of some kind. The one just described

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Procedure can have two different variants. The first variant consists in that a voltage Y is formed which is equal to the mean value of the voltages V ^. and V is ₂ measured at the outermost electrodes, ie, the top and bottom electrodes. These voltages T 1 and V ₂ are the most representative voltages of the conductivities of the present solutions. It is clear that all electrode voltages which are above this mean voltage Y belong to a voltage group which characterizes the solution with the higher conductivity. Conversely, the electrode voltages that are below vert Y belong to a voltage group that characterizes the solution with the lower conductivity.

If any of the voltages of the electrodes that are in the solution with the higher conductivity is denoted by Y. and assuming that Y ^. the tension of the extreme Electrode that corresponds to this solution of higher conductivity and that Yp is the voltage of the other outermost electrode that then immersed in the solution with the lower conductivity, then it is possible to calculate the smallest value that

V. can take, which makes it possible to use the permissible Yertei-

d
which can show the electrode voltages belonging to the voltage group that characterizes the solution with the higher conductivity. This calculation gives the ratio E of the conductivities of the solutions, which is equal to the ratio of the extreme _{voltages Y ^ and Y 2 of} the two solutions: -π-

The smallest value V-? _m: i _{n of} any voltage V. for the group of higher values is of course equal to an average voltage V, from which it follows:

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V ^ ₁₊ V ₅ 1 + E
¹ ^ and

The result of this calculation is that the smallest voltage T.. , which is permissible in the first "variant, of the ratio the conductivity R depends on the following relationship:

if they are in percentages of the voltage V _x . the outermost electrode immersed in the solution with the higher conductivity. The permissible course of this distribution is shown in FIG. 2 by curve a as a function of the ratio

E = Ii

shown.

According to a second variant of the method according to the invention, the lower limit value of the voltage group V. with respect to the

ο the highest voltage can be determined that corresponds to the electrodes in the solution with the lower conductivity. In this case, all electrode voltages that are above this highest voltage can be assigned to a voltage group.

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which identifies the solution with the higher conductivity. As with the first variant, the -second variant the largest ratio between the voltage V ^, which is the greatest voltage among the voltages corresponding to the solution with the greater conductivity, and the smallest

! Voltage V. be calculated to the permissible distribution of the

"

! Get voltages of the electrodes that are in solution with the

higher conductivity are immersed. Since the smallest value of '. V. is the largest value of the voltages of the electrodes immersed in the solution with the lower conductivity, one immediately obtains:

V ^, VH
and it:

where V.. Expressed in pr ο ζ numbers of the greatest voltage of V. is. This distribution is shown in FIG. 2 by curve b as a function of the ratio of the conductivities R. FIG. 2 shows that, depending on whether the mean value V or the largest value of the voltages, belongs to the group of the lower voltages belong, is used as a reference value, which determines the affiliation to one of the two measured voltage groups allowed to get different feasible distributions. Although the second variant allows distributions, which are practically twice the distributions that are permissible in the first variant, but they take into account not a possible reduction in the ratio V- that is to it

can lead to the two groups of higher and lower voltages getting mixed up, because their conductivities lie close to each other and the greatest tension of the group of the lower Tensions differ very little from the higher tensions

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which makes the distinction very difficult.

The choice of one or the other variant depends on the. essentially of the stability of the ratio V / Vp ^at) »as characterizes the two existing solutions. When the conductivities are very different, ie. if the ratio V ^ / V ^ S ^r ° ß ^ ^s ^ and if there is no risk of it dropping to 10, for example, the second variant is more advantageous, since it leads to a permissible distribution among the voltages that is practically twice that as large as the distribution in the first variant. However, if there is a risk that the ratio V ^ / Vp will be less than xv, the first variant is preferred.

Whichever variant of the method is used, the devices for carrying out the method have common elements in each pail, which are shown schematically in FIG. The circuit shown in FIG. 3 contains an output block 20 for the voltages of the electrodes, a control block 22 and a block 24 for the logical processing of the information supplied by block 20. The block 20 consists of a reference voltage source 26 and an equal number of circuit paths 28 Xfie electrodes. Each of these conduction paths has an input 30 which receives the voltage taken from the terminals of one of the resistors 10 associated with the electrodes immersed in the solutions. This input is connected to a linear integrator 32, the output of which emits a voltage which increases linearly over time. At the output of the integrator there is a comparator 34- _} which receives the reference voltage output by the circuit 26 and the integrated voltage output by the output of the integrator 32. The comparator is therefore in one or another of two states which it can assume, depending on whether the integrated voltage it receives is above or below the reference voltage.

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The logical processing block 24 consists of an input register 4-0 which is connected to each of the comparators 34. The register can store the state of each of the comparators. At the output of the input register there is an output register 42, to which the content of the input register 40 is transferred if it has stored the state of the comparators.

The control block 22 allows the flow of the work processes to be controlled the evaluation of the electrode voltages in block 20 and the logical processing in block 24, as it will later in is represented individually.

The circuits shown schematically in Figure 4 are general known. The linear integrator can for example consist of a current-voltage converter which has an integration capacitor supplied in such a way that the capacitor charges itself via a constant current, which results in a linear integration in the capacitor causes. The comparator can be formed by a functional amplifier. This amplifier can preferably be equipped with a be coupled to a monostable circuit with a short switching time, which allows changes in the state of the comparator to be displayed, indenr a pulse at the terminal of the output of the monostable Circuit appears. The input register can consist of the same number of elementary memories as comparators, where each storage element stores the occurrence of a pulse at the output of the monostable circuit of the comparator.

It is advantageous to connect the blocks 20 and 24 to one another via an intermediate part 44 made of photoelectric insulators 46 exists.

Figure 4 shows schematically the control device in the case of the first Variant. This device comprises a conduction path, the inputs 50 and 52 of which are those at the terminals, of the resistors received voltages that are connected to the external electrical

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which are connected at the very top and at the bottom and a linear integrator 54- which is the sum of the voltages of the external electrodes receives. This integrator preferably has a time constant that is twice as large as the time constant of the integrators 32 associated with each of the electrodes so that at the output of the integrator 54- the integrated mean voltage is obtained. Of course, devices that first take the mean value of the voltages occurring at terminals 50 and 52 and then an integrator identical to the integrators 32 can be used.

The integrated average output at the output of the integrator 54 Voltage is compared in a comparator 56 with that from the source output reference voltage compared. The comparator can also be formed by a puncture amplifier which is coupled to a monostable circuit with a short switching time. When the integrated mean voltage reaches the reference voltage, the device 56 emits a pulse which is responsive to the Input register 40 optionally via a photoelectric Isolator 58 is transmitted. This impulse triggers the storage the states of the various comparators 34 assigned to each of the electrodes into the input register 40. The registry 40 thus stores the number of comparators that have already flipped when the mean integrated voltage reaches the reference voltage. The theoretical considerations developed above have shown that this number is the number of voltages with the higher value or, in other words, the number which represents electrodes immersed in the solution with the higher conductivity. The difference becomes the number of the electrodes immersed in the solution with the lower conductivity. When this storage is completed, the measurement is finished and the elements are reset to zero, as will be seen later.

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In the second type of embodiment, that shown in FIG. 5 is used Control circuit related. In this embodiment, the. the pulse emitted by the comparator 34 of the voltage measuring paths used to change the value of the reference voltage, which is emitted from the source 26. This voltage initially assumes a first value, which is retained until then

\ the voltage output by any of the integrators reaches the reference voltage. If one of the integrators of the solution

, with higher conductivity those lying above the reference voltage Reaches the value, the assigned comparator tilts and causes the pulse of the monostable circuit connected to it to be shorter

: Switching time a decrease in the reference voltage by an amount D, which is the permissible distribution in the solution with higher conductivity represents. This new value of the reference voltage, which is below the first value, immediately causes the comparators to overturn with itself, which are connected to integrators, whose output voltage is equal to or greater than the second value of the reference voltage is. At this point all of those integrators that are connected to electrodes have been put into the solution with the higher conductivity are immersed, then a causes their comparators to overturn. The impulse that makes a change of the value of the reference voltage can be used at the same time to store the states of the

^; To effect comparators, for example via a photoelectric isolator 60 in the input register 40. The measurement of the number of overturned comparators is now complete.

When the storage by the input register 40 is completed in one or the other variant, the content of the Register 40 transferred to the output register 42, which contains the information relating to the number and position of the electrodes that are in the solution with the higher conductivity. The devices shown schematically in FIG. 6 enable the various switching elements to be reset to zero so that a new measurement can be carried out. the

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Devices shown in FIG. 6 for resetting the switching elements, which are included in the control block 22 can be, on the one hand can generate a command that entails that the measuring electrodes and the common electrode be short-circuited via the interrupter 62 and, on the other hand, the integrators 32 and the storage elements of the Reset input register 4-0 to zero. When disappearing These commands to reset the elements to zero start a new measuring cycle.

It is advantageous to tell an operator the number of electrodes that are immersed in the solution with greater density, even if it is non-conductive, as this information gives directly the height of the iris level of the fluids. The information in the output register is used for this purpose corresponds to the lowest electrode and which makes it possible to see whether this electrode is among the group of electrodes appears or not that are in the solution with the higher conductivity. In the case where the bottom electrode is immersed in the solution with the higher conductivity, the information of the output register is directly on the output terminals of the "device. In the event that the lowest electrode is not in solution with the If the conductivity is higher, the information in the output register is inverted.

The output signal can be converted into an analog signal, which is proportional to the number of electrodes immersed in the denser solution, from which directly the position the level of separation can be obtained.

In the present case, the voltages at the terminals of the measuring resistors result from the current flowing across the fluids flows, but the principle of the invention is also applicable

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an evaluation of all physical properties of the fluids, applicable by a measurement * di-e "these properties a into discrete-. ■ t electrical. voltages = converts ;;. _: '-.

From the above it can be seen that the method according to the invention and the gate direction according to the invention allow a separation from the absolute values of the conductivities, since only the voltage differences and therefore the differences in conductivities are taken into account.

The "c differential ^{precision J} '.., of the measurements allows a precise localization of the separation level of the fluids even in the case in which the fluids have very close electrical conductivities.

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Claims (9)

Claims * ί. Method for locating the level of separation between two fluid phases with different electrical conductivity, thereby characterized in that a number of identical electrodes distributed along the vertical direction are immersed in both phases and is connected to a series of identical resistors that a common electrode in both phases is immersed that an electric voltage is applied between the common electrode and each pair of electrode resistors is that the voltages appearing at the terminals of each of the resistors are measured, the measured Voltages in a narrow distribution either an upper value for the electrodes immersed in the phase, which has a higher conductivity, or a lower value for the electrodes immersed in the phase which has a lower conductivity, and that the number of in a narrow distribution equal to the upper or the lower Voltage equivalent to a value is counted, which supplies the position of the separation level with regard to the number of electrodes. 2. The method according to claim i, characterized in that for Counting the number of voltages that have the upper value, a mean voltage is formed that is equal to half the sum of the voltage of the top electrode and the voltage of the lowest electrode, and that this mean voltage is linearly integrated that the integrated mean Voltage is compared with a fixed reference voltage and that at the time when the mean integrated voltage reaches the reference value, the number of integrated voltages are counted that have exceeded the reference value, xiras delivers the required number. 709814/0797 3- The method according to claim 1, characterized in that for Count the number of voltages with the upper value linearly the voltages measured at the terminals of all resistors be integrated so that the integrated voltages are compared with a reference voltage which has a first value, that when one of the "integrated voltages reaches this first value of the reference voltage, the reference voltage to one the second value is reduced, which differs from the first value by an amount equal to the assumed distribution, which show the values of the group of higher voltages, and that the number of integrated voltages with a value above the second. The value of the reference voltage is always counted when this is decreased, which results in the number sought. 4-, Device for locating the level of separation between two Pluid phases with different electrical conductivities for carrying out the method according to Claim 1, characterized by a number of identical electrodes (6) immersed in the two phases (2, 4-), along the vertical one Direction are distributed and each connected to a number of identical resistors (10) by a common Electrode (8) immersed in both phases (2, 4 ·) is, by a voltage source (12), whose voltage poles with the common electrode (8) and each pair of electrode resistors (6, 10) are connected by a means for measuring of the voltages appearing at the terminals of each of the resistors, with the measured voltages in a narrow distribution either an upper value, for the electrodes that are immersed in the phase, which have a higher conductivity has, or a lower value for the electrodes that are immersed in the phase that has a lower conductivity has, equal, and by means of counting the number of voltages that are in a narrow distribution have upper or lower value. 7098U / 0797 5- device according to claim 4, characterized in that the Means for counting the number of voltages with the upper value a reference voltage source (26), as many conduction paths as electrodes, each of the conduction paths being a linear integrator (32), on which the voltage tapped at the terminals of the resistor (10) of the electrode (6) is applied, and one Contains comparator (34) at which the voltage output by the integrator (32) and the reference voltage are applied, a logical one Device (24) which at a certain point in time of the measurement counts the number of comparators (34) that are in one are certain state, and a control device (22) for the application of the voltage of the voltage source ensures and commands that the state of the comparators (34) is stored by the counter (24). 6. Apparatus according to claim 5 _5, characterized in that the control device comprises an integrator (54) for the mean voltage between the voltage of the uppermost electrode and the voltage of the lowermost electrode and a comparator (56) on which the mean integrated voltage and the Reference voltage lie, the counter being controlled at the point in time at which the comparator changes its state. 7. Apparatus according to claim 5 »characterized in that the Control device (22) means a device which gives the reference voltage a first value, and has a device, which reduces the reference voltage at a point in time to a second value which differs from the first value by an amount which is equal to the assumed distribution that the values of the group of higher voltages show at which the highest increased integrated voltage reaches the first value, whereby the counter is activated when the reference voltage is lowered. 7098U / 0797 8. Device according to. Claim 5j characterized in that the logic means (24) for counting the number of comparators that are in a particular state photoelectric isolators connected to the comparators " is. 9. Apparatus according to claim 4-, characterized in that the counting device (24) from an input register ( ² K)) which consists of memories which are connected to the comparators (34) and which store the state of each comparator (34) , and an output register (42) is formed, to which the result stored in the input register (40) is transferred after the measurement. IO. Device according to claim 4, characterized by means to reset to Full, which is operated 'after the measurement is stored and _r resets the integrators and the counter on UuIl and short-circuits the common electrode with the number of electrodes. 7098U / 079 7