JPH0331373B2 - - Google Patents

Description

Detailed Description of the Invention Technical Field The present invention provides a method for measuring the interface position between liquids with different specific gravities that have phase-separated after a reaction has been promoted by stirring and then stopped for a period of time. It relates to a measurement method when a layer is formed and/or when the clay content of the upper liquid is high.

BACKGROUND OF THE INVENTION It is known that one method of measuring the interface position between phase-separated liquids with different specific gravity is to use a self-balancing interfacial meter. The interface meter used for this purpose consists of suspending a displacer made of a material with a higher specific gravity than any liquid in the liquid using tape or cables, and applying a constant tension such that the displacer is in equilibrium at the interface position. In other words, a force obtained by subtracting the buoyancy of the displacer at the interface between the two liquids from the weight of the displacer is applied to the tape or cable immediately above the displacer, and this causes the displacer to follow the interface position. The interface position is measured in this way.
This method has the advantage of allowing automatic and remote measurement.

However, when measuring the interface position of two liquids that have been separated after stirring the liquid using an automatic equilibrium interfameter such as a lever, conventional methods have been used to measure the position of the interface between two liquids that have been separated after stirring. It has been considered impossible to measure liquids that produce bubbles, liquids that have thixotropic substances on their surfaces, or liquids that are extremely clayey. This is because in this conventional method, the displacer is suspended with the above-mentioned constant tension that is balanced at the interface position. The descending force due to the force obtained by subtracting the tension force from the weight (or the descending force due to the force obtained by subtracting the tension force and the buoyancy force of the displacer from gravity when in liquid) is extremely small. This is because, with this small driving force, when the displacer is lowered into the liquid for measurement after stirring, if there is a solid coating, it will not be able to break through the solid coating, which may result in measurement being impossible. Furthermore, if air bubbles are formed in the liquid, the air bubbles will adhere to the displacer and change the buoyancy, thereby increasing measurement errors. Furthermore, when a highly thixotropic substance is present on the surface, if the driving force is small, the displacer will stop on the surface or become unable to move up and down in the liquid.

A known method is to allow the displacer to stand still after stirring and then release the suspension tension to allow the displacer to fall freely into the liquid, thereby breaking through the solid coating.
However, in this case, it is necessary to solve problems such as the impact caused by the displacer colliding with the bottom of the liquid tank (for example, a tank) and the wear and damage of related parts when it falls, or to avoid this problem. When a friction deceleration mechanism is installed in a vehicle, the frictional force reduces the downward force, so it is necessary to solve the problem of difficulty in penetrating the solid coating. In addition, if you leave the displacer in the liquid in an automatic equilibrium state after stirring and before separating the two liquids to avoid the problem of breaking through the solid film, the solid film may adhere to the tape or cable after standing. This results in problems such as impeding smooth movement and increasing measurement errors. Moreover, none of these offers a solution to the problem of air bubbles adhering to displacers, tapes, etc. For this reason, for example, in the case of the above-mentioned liquid, it has been considered impossible to automatically measure the interface position using a self-balancing interface meter as a practical matter.

In cases where automatic measurement using a self-balancing interface meter is not possible, measurement is conventionally performed by sampling. This method collects liquid from various depths in the liquid (for example, at intervals of several centimeters in the case of a storage tank) and estimates the interface position from the sampled liquid. This method is also known as a method for confirming the performance of an interface meter and is the most basic method.

However, this kind of sampling-based measurement requires the inspector to climb on top of the storage tank, for example, which has the drawback that it is not easy to work and can be extremely dangerous depending on the type of liquid being measured. There is. Moreover, only rough measurements can be made based on intermittent data depending on sampling depth intervals, and it is practically difficult to carry out continuous automatic and remote measurements, so for example, the realization of an automatic movement system in conjunction with a computer, etc. This was a major obstacle.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a method for automatically and remotely measuring the interface position even for liquids that would otherwise have had to rely on conventional sampling methods.

Structure of the Invention When measuring the interface between liquids having different specific gravity, the present invention suspends a displacer made of a material having a higher specific gravity than any of the liquids within the liquid using a tape or cable, and suspends the displacer in the liquid using a tape or cable. In a method of measuring by automatically controlling the position of the interface to achieve force balance, first, the buoyancy of the displacer in the liquid having a higher specific gravity is subtracted from the weight of the displacer. Once a small force is applied to the tape or cable, or a force obtained by subtracting the buoyancy of the displacer at the interface from the weight of the displacer, the displacer is temporarily removed. The displacer is lowered and held lower in the liquid, and then a force equal to the weight of the displacer minus the buoyant force of the displacer at the interface is continuously applied to the tape or cable. This interface measuring method is characterized in that the displacer is made to follow the interface by causing the displacer to follow the interface. In addition, in order to obtain better measurements, it is necessary to apply a force that is calculated by subtracting the buoyant force of the displacer at the interface from the weight of the displacer to the tape or cable before moving to the stairs. The displacer may include a step for forcibly raising the displacer by applying a force greater than the weight of the displacer to the tape or cable. In order to further reduce the measurement error, after the step in which the displacer is forcibly raised, the buoyancy of the displacer in the liquid having a higher specific gravity is subtracted from the weight of the displacer. A force smaller than the weight of the displacer and a force greater than the weight of the displacer are alternately applied to the tape or cable to create a staircase for raising and lowering the displacer.
Great effects can be obtained by repeating this more than once. Furthermore, in order to carry out this method industrially, it is preferable that the force applied to the tape or cable be controlled automatically or remotely.

In other words, in order to make soap etc., first stir the reaction thoroughly and then let it stand for a certain period of time.
When measuring the interface after the liquid has completely separated, the displacer is lowered after stirring and before a solidified layer is formed on the surface, and after the two liquids have separated, it is pulled upward by automatic tension control. When pulling upward, it is possible to reduce measurement errors by first pulling up with a large force to separate it from the deposits below, and then repeating the up and down motion to separate the deposits. Furthermore, the idea is to perform these actions in a planned manner.

Embodiment FIG. 1 generally shows schematically the case in a storage tank as an example of implementing the method for measuring the interface position according to the invention. This storage tank 4
accommodates and stores two types of liquids that have different specific gravity and undergo phase separation, namely a first liquid 1 with a heavy specific gravity and a second liquid 2 with a light specific gravity. This liquid 1
Since liquid 2 and liquid 2 are in a phase-separable relationship,
After a certain period of time has passed, the layer is clearly separated into two layers, forming an interface 20, as shown in the figure. These liquids can be passed through suitable inlet or outlet passages 15 or 1.
6 into the storage tank 4, and can also be supplied to the outside of the storage tank 4 through an inlet or outlet passage 15 or 16. (Aisle 1
5 and 16, it is preferable to use either passage for introduction, and for outflow, it is preferable to use passage 16 for items with light specific gravity and passage 15 for items with heavy specific gravity. ) Also in this supply,
For example, an outflow passage 15 and/or 16 is provided so that either the first liquid 1 having a higher specific gravity or the second liquid 2 having a lower specific gravity can be taken out independently, and an interface 20 which is a feature of the present invention to be described later. It is now possible to guarantee such separation of liquids based on position measurements. Storage tank 4
A stirring blade 5 is provided inside, and the stirring blade 5 can be rotationally driven by a stirring drive device 6 provided on the top wall 4A. Further, reference numeral 3 indicates a solid film formed on the surface of the second liquid 2 having a light specific gravity. That is, it is assumed here that the second liquid 2 is a liquid that forms a solid film when exposed to air.

In the measuring method of the present invention, a displacer 9 made of a material with a specific gravity greater than that of any of the liquids is immersed in these liquids, and this displacer 9 is finally positioned at the interface 20. The principle of self-balancing interface measurement is applied, which is based on balancing the tension exerted by the tape or cable with the difference between gravity and buoyancy, and measuring the interface position accordingly. However, the feature of the present invention lies in the switching control of the suspension force of the displacer 9, as will be described later.

The displacer 9 is connected to one end of a flexible hanging member 10 such as a tape or cable, and is suspended within the storage tank 4. The other end of the hanging member 10 is wound around and fixed to a tension control take-up drive drum 13 provided in the gauge head 12, and the drive drum 13 prevents the displacer from moving at the interface between the two liquids from the gravity of the displacer. Tension is applied to the hanging member 10 so that a tension equal to the value obtained by subtracting the buoyant force is applied to the hanging tool immediately above the displacer. This tension control is carried out by feeding back a value detected by a tension detection mechanism generally indicated by reference numeral 11. Such a tension detection mechanism 11 and the tension control technology itself based on this detected value are basically disclosed in Japanese Utility Model Publication No. 52-55080 and Publication No. 52-55081. The gauge head 12 is also equipped with an interface position detection wheel 14, which detects the lifting/lowering position of the displacer 9 based on the amount of extension/retraction of the suspension member 10, that is, the interface position that will eventually reach equilibrium in the liquid. It is now detectable. The displacer 9 is vertically movable within the storage tank 4 and can be moved between an upper stopper 7 provided on the top wall 4A and a mounting leg 8 provided on the bottom wall 4B. The upper stopper 7 raises the displacer 9 when the liquid flows violently when the liquids 1 and 2 are introduced into the storage tank 4 or when the stirring blade 5 is rotationally driven by the stirring drive device 6, and is indicated by the reference numeral 9''. Therefore, it is desirable to have an appropriate interlock mechanism to ensure that the locking state is maintained until such work is completed.On the other hand, the mounting legs 8 are 9'' so that when the displacer 9 is submerged in the liquid, it will not come into close contact with the bottom wall 4B and the static pressure of the liquid 2 will be applied from the bottom surface as well.
This is to provide support as shown in , and to provide a guarantee that the subsequent levitation will occur reliably.

Now, to explain the measurement method according to the present invention, first, when introducing the mixed liquid of liquid 1 and liquid 2 into the storage tank 4 or stirring with the stirring blade 5, the displacer 9 is raised and is indicated by the reference numeral 9''. The displacer 9 and the hanging member 10 are protected by being locked to the upper stopper 7 in this way.
At this time, it is possible to calibrate the detection value by the measurement position, that is, the interface position detection wheel 14, based on the upward limit of the displacer 9.

After the stirring is completed, the displacer 9 is lowered while applying an appropriate tension to the suspension member 10. This descent occurs before the solid film 3 is formed.
That is, this is performed before the two liquids are allowed to stand still and are separated as shown in the figure. Further, the appropriate tension at this time is intended to cause the displacer 9 to descend at a relatively gentle speed without causing it to fall freely. Therefore, for example, the tension is sufficient to allow sedimentation in the first liquid 1 having a heavy specific gravity, that is, the force obtained by subtracting the buoyancy of the displacer 9 in the liquid 1 from the weight of the displacer 9, and further subtracting the frictional force. The torque of the motor that drives the drum 13 is set so that a small force is applied to the suspender of the displacer 9. Such setting method and setting circuit are disclosed in Utility Model Application Publication No. 54-74565.
It is disclosed in the publication No. Alternatively, while the torque of the drive motor is released and the displacer 9 is falling due to the weight of the displacer 9, the force for the displacer 9 to balance itself at the position of the interface 20, that is, the weight of the displacer 9, is intermittently applied. Torque may be applied to the take-up drive drum 13 so that a force obtained by subtracting the buoyant force at the interface 20 of the displacer 9 acts on the suspender of the displacer 9.
To carry out this intermittent operation, the circuit of the drive motor of the drum of the gauge head 12 may be controlled by a program so as to be switched between automatic and disconnected intermittently. Due to this gradual sedimentation, the displacer 9
is placed on the mounting leg 8 as indicated by the reference numeral 9'.
Thereafter, the two liquids gradually separate, forming a clear interface 20 as shown in the figure, and a solid film 3 is gradually formed on the surface of the upper liquid 2. Therefore, the displacer 9 is not affected by the solid coating 3.

After the two liquids are allowed to stand until they are completely separated, first, a force greater than the weight of the displacer 9 is applied to the suspension member 10 to forcibly raise the displacer 9. This rise moves the displacer 9 within a range that does not exceed the interface 20. For this purpose, a predetermined force can be applied for a predetermined time and can be increased more rapidly. However, movement that disturbs the interface 20 or creates bubbles due to this rise is undesirable. During this upward movement, torque is applied in an open loop to the motor that drives the tension control take-up drive drum 13 provided in the gauge head 12, and a force greater than the weight of the displacer 9 is applied to the suspension member 10. By applying this force, the displacer 9 that is in close contact with the mounting leg 8 is separated, and the solid film 3 adhering to the hanging member 10 is stripped off.

Thereafter, a force obtained by subtracting the buoyancy of the displacer 9 at the interface 20 from the weight of the displacer 9 is applied to the suspension member 10 so as to be applied to the suspender of the displacer 9, so that the displacer 9 moves to the interface 20.
Make it stand still at the position. This position at rest is detected by the interface position detection wheel 14,
This is to know the position of the interface. This step is similar to normal self-balancing interface measurement and will not be described in detail.

In the measurement example described above, the displacer 9 was first placed on the mounting leg 8, then forcibly raised, and then equilibrated at the interface. However, in some cases it is possible to equilibrate the displacer 9 to the interface position immediately after it has been placed and held on the support leg 8. Conversely, after the displacer 9 is placed on the mounting legs 8, a tension greater than the weight of the displacer 9 is applied as described above to forcibly raise it, and then After stirring, the displacer 9 is lowered again by the means used to lower it several times, and the solid coating 3 adheres to the suspension member 10.
Also, after peeling off the bubbles attached to the displacer 9 and the hanging member 10, by balancing the displacer 9 at the position of the interface 20, measurement with less error than at the position of the interface 20 can be performed. can. This operation can be performed by switching the drive motor circuit of the winding drive drum 13 between winding and lowering with a switch.

Looking at the circuit of the drive motor for the drum 13, all of the above steps can be accomplished by switching between automatic/hoisting/lowering/off according to a program.

As described above, when measuring the interface between two liquids separated after stirring, the present invention suspends the tension obtained by subtracting the buoyancy of the displacer at the interface from the weight of the displacer so that the displacer is in equilibrium with the interface. Before measuring the holding member, first reduce the holding force to be smaller than the force that balances at the interface, or slowly lower the holding member by the gravity of the displacer while applying an equilibrium force intermittently. After the two liquids are separated by standing still,
Apply a lifting force that is balanced at the interface, or lift the displacer upwards with a lifting force greater than the weight of the displacer while it is down, or force a lift followed by lifting the displacer. It is also possible to reduce the force applied to the suspension member 10, forcibly lower it, and repeat such raising and lowering an appropriate number of times, thereby peeling off the solid coating attached to the suspension member 10, and then equilibrating it to the interface position. be.

As described above, in the present invention, before equilibrating the displacer at the interface, first, the suspension force is made smaller than the force at equilibrium, or the action time is controlled intermittently to lower it, and this state is maintained. After that, either the liquid is allowed to stand still and the interface is stabilized, and then the interface is brought to equilibrium, or the suspension force is made greater than the force at equilibrium to forcibly move it upwards, and such lifting and lowering is carried out an appropriate number of times. After repeating, let the interface equilibrate,
Since the interface position is measured in this equilibrium state, the effects are as follows.

By lowering the displacer at a slow rate before a solid film is formed on the surface, conventional drawbacks such as solid films and shock are avoided, and measurements in liquids that produce solid films are uninterrupted.

Since the displacer is raised and lowered as necessary, it becomes possible to release the deposits on the displacer and the hanging member, and the drawbacks of the conventional method can be eliminated.

The desired lifting and lowering of the displacer can be achieved by controlling the suspension force or by controlling the force to be applied intermittently, so the control technology is easy, and the interface position can be measured continuously, automatically, and remotely at low cost. can be achieved.

Measurement accuracy can be improved.

Note that the present invention is not limited to the embodiments described above, and the actual technical means of controlling the suspension force or controlling the force to act intermittently may be performed by any known method. good. Moreover, the features of the present application can be applied not only to interface meters but also to liquid meters, and measurement accuracy can be improved.

[Brief explanation of the drawing]

FIG. 1 is an elevational view, partially in section, schematically showing an apparatus for carrying out the measuring method of the present invention. 1...first liquid, 2...second liquid, 3...
Solid film, 4... Storage tank, 5... Stirring blade,
6... Stirring drive device, 7... Upper stopper, 8
... Placement leg, 9 ... Displacer, 10 ... Hanging member, 11 ... Tension detection mechanism, 12 ... Gauge head, 13 ... Winding drive drum, 14
...Wheel for detecting interface position, 15, 16...Passway, 20...Interface.

Claims (1)

[Scope of Claims] 1. When measuring the interface between liquids with different specific gravity, a displacer made of a material with a higher specific gravity than any of the liquids is suspended in the liquid with a tape or cable, and the displacer is suspended in the liquid using a tape or cable. In a method of measuring by automatically controlling the position of the interface to achieve force balance, first, the buoyancy of the displacer in the liquid having a higher specific gravity is subtracted from the weight of the displacer. A small force is applied continuously to the tape or cable, or a force obtained by subtracting the buoyancy of the displacer at the interface from the weight of the displacer is applied intermittently to the tape or cable. Lower the sprayer and hold it lower in the liquid, then
An interface measuring method comprising: causing the displacer to follow the interface by continuously applying a force obtained by subtracting the buoyancy of the displacer at the interface from the weight of the displacer to the tape or cable. 2. Applying a force greater than the weight of the displacer to the tape or cable before moving to the staircase where a force equal to the weight of the displacer minus the buoyancy of the displacer at the interface is continuously applied to the tape or cable. 2. The interface measuring method according to claim 1, further comprising a step for forcibly raising the displacer by acting on a cable. 3. After the staircase that raises the forcible displacer, before transitioning to the staircase that continuously applies a force equal to the weight of the displacer minus the buoyancy of the displacer at the interface to the tape or cable, a force that is less than the weight of the displacer minus the buoyancy of the displacer in the liquid with a higher specific gravity;
a force greater than the weight of the displacer;
3. The interface measuring method according to claim 2, wherein steps of raising and lowering the displacer are repeated one or more times by alternately acting on a tape or a cable. 4. The interface measuring method according to claim 1, wherein the force applied to the tape or cable can be controlled automatically or remotely.