JPH0572104A - Dropping ball type viscometer for process control - Google Patents

Abstract

PURPOSE:To select the passing detector of a device in which a bellows as pneumatic type intermittent operating pump is incoporated as the integral structure with a measuring pipe and solve the trouble of the constitution, as for a dropping ball type viscometer used for process control. CONSTITUTION:For a dropping weight, and measuring pipe and a detector for detecting the dropping ball, it is desirable to mainly use an optical means, since the chance of intrusion of error in the measurement process is much, in the conventional method where magnetism and electromagnetism are utilized. Accordingly, the measuring pipe is used in tilt form, and a ball is used as the dropping weight, and a dropping ball type viscometer is used. Accordingly, the device which can correctly measure the viscosity of a measured liquid and the properties in a wide range can be obtained.

Description

Detailed Description of the Invention

[0001]

[Industrial application] The electric wire industry, in which insulating coatings such as enamel electric wires are applied to copper wires, the electronic parts assembly industry, in which moisture-proof insulating varnish is applied to printed circuit boards, magnetic materials, cassette tapes; V
TR tape: In the coating process of various industries that process semi-finished liquid adhesive target materials in the manufacturing process, such as the magnetic recording material industry that coats discs or the paper manufacturing industry that coats the coating agent on the surface of paper, paint, Depending on the viscosity of the coating agent such as varnish, the quality of the finished surface coated on the work piece, the function of the processing surface, the material cost, etc. differ, so during the process of controlling the viscosity of the coating agent to the optimum value,
It is necessary to perform automatic viscosity adjustment and viscosity control of the coating agent.

A viscometer for process control used in such a process is such that a cylindrical rotor is rotated in a liquid,
Rotational viscometer that detects the viscosity of the liquid by viscous resistance torque generated in the rotor, drop a cylindrical drop weight or a spherical drop ball into a vertically or diagonally installed measuring tube, and in the liquid inside the measuring tube Viscometers of various measurement principles have been put to practical use, such as a method of measuring the viscosity of a liquid to be measured by measuring the time required for a falling weight or a falling ball to pass between preset detection gauges.

Of the above-mentioned various process control viscometers, the present invention is relatively well used because of its good maintainability and stability, and its high accuracy especially for low-viscosity liquids. It is related to the composition of the total.

[0004]

2. Description of the Related Art Conventionally, a falling weight type viscometer (including a falling ball type) which has been widely used as a viscometer for process control of this kind.
The measurement principle of is first explained. FIG. 3 is a vertical cross-sectional view of the measuring unit showing the basic principle of the falling weight type viscometer. In the figure, 1 is a vertically set measuring tube, and 2 is a cylindrical drop weight inserted into the measuring tube. At the lower end of the measuring tube 1 is a bottom plate 3
Is provided to prevent the liquid from leaking when the measuring tube 1 is filled with a liquid to be measured (hereinafter referred to as a sample liquid) whose viscosity is to be measured. A passage detector 4a which is separated from the upper and lower parts of the middle of the measuring pipe 1 by a distance L and detects the passage of the falling weight 2 from outside the measuring pipe when the falling weight 2 falls inside the measuring pipe 1 and transmits a signal. , And 4b are installed. It was customary to apply various non-contact detection principles to these passage detectors, such as detectors using the magnetic principle, detectors using the electromagnetic principle, and detectors using the optical principle. ..

When the dropping weight is dropped from the upper end of the measuring tube while the measuring tube 1 is filled with the sample solution, the dropping weight receives the viscous resistance of the sample solution in the tube, and first, the falling weight of the upper passage detector 4a is detected. After passing through the position and then the position of the lower passage detector 4b, it falls to the lower end position of the measuring pipe 2'shown by the dotted line and stops. A gate signal G is created from the two passage signals S-1 and S-2 emitted from the passage detectors that are different in time, and the number of pulses is measured from a clock pulse CP having an appropriate frequency as shown in FIG. As a result, CT can be calculated as a numerical value related to the viscosity and density of the sample liquid. Actually, the density of the sample solution is considered to hardly change even if the solution concentration changes due to process condition changes and the change range of the solution concentration is small. It doesn't matter.

The above is the principle of the falling weight type viscosity measurement. If the measurement is an experimental measurement only once, the falling weight is 2'of FIG.
The measurement is ended by dropping to the position of, but when it is desired to repeat the measurement a plurality of times experimentally, a lid is also provided on the upper end of the measuring tube 1 in FIG. For each measurement, the measuring tube 1 may be turned over to return the falling weight to the upper end position of the measuring tube, and the apparatus may be turned over again to start the falling weight to repeat the measurement.

When the above-mentioned drop weight type viscometer is used for process control, in order to always measure in response to process changes, it is necessary to repeatedly perform measurement at regular time intervals.
And it is necessary to always replace the sample liquid in the measuring tube with the liquid in the tank so that the sample liquid represents the state change. For that purpose, it is necessary to automatically return the falling weight that has dropped to the bottom of the measuring tube to the upper end of the measuring tube, and at the same time to flow a new sample solution into the measuring tube to replace the solution each time the measurement is repeated.

As a method of replacing the liquid in the measuring pipe and returning the falling weight that has dropped to the bottom of the measuring pipe to the upper end of the measuring pipe at the same time, the inventor of the present application used a process using a pneumatic intermittent operation pump (for example, using bellows). We have already applied for the invention of the falling weight type viscometer for control. (Application on August 30, 1991)

[0009]

[Problems to be Solved by the Invention] Above, August 3, 1991
Taking the configuration of the invention of the 0th application as an example, the problems of the magnetic type, electromagnetic type, and optical type non-contact detectors that are used as the passage detectors of ordinary drop weight type viscometers, and The problems of this type of viscosity measurement method related to the measuring principle of the falling weight type viscometer itself and the problems that should be further studied technically will be examined deeply. FIG. 5 is a cross-sectional view showing the configuration of the process control drop cone viscometer of the above patent application. In the figure, 1 is a measuring tube, and measuring tube 1
Two upper and lower passage detectors 4a, 4 provided outside the
When the falling weight 2 inserted in the measuring tube 1 falls in the sample liquid by b and passes through the positions of the passage detectors 4a and 4b, the falling weight 2 of the falling weight 2 is contacted from the outside of the measuring tube 1. In order to detect the passage time, whether the operating principle of the detector is magnetic type,
It is limited to the electromagnetic type or the optical type, and the material of the measuring tube 1 and the falling weight 2 must be selected strictly according to the detection principle.

In the conventional viscometer of this type, the simplest method of the non-contact detection principle is that the first method uses a bar magnet as the falling weight 2 and a non-magnetic material as the measuring tube 1, and the measuring tube 1 Two reed switches 4a, 4 installed outside the
There has been a magnetic detection method of activating b to detect the passing time of the falling weight 1.

In the second method, the dropping weight is made of a ferromagnetic material and the measuring tube 1 is made of a non-magnetic material, and the dropping weight 2 is passed through the measuring tube 1 to set it outside the measuring tube 1. There is an electromagnetic detection method in which a rapid change in impedance occurs in each of the induction coils 4a and 4b at every other time to detect the difference in passing time of the falling weight 2.

The third method is the case of optical detection, in which the measuring tube 1 is made of a material having good light transmittance such as hard glass, and the light source is applied from the outside of the measuring tube 1 as shown in FIG. 6-a. 9a,
By setting the light receiving element 9b at a position sandwiching the measuring tube 1, a method of using a light transmission type detector for detecting the interruption of light when the falling weight 2 passes, or as shown in FIG. The light 10-a is projected from the light projector on one side of the outer surface of the measuring tube 1, and the reflected light 10-b from the falling weight is reflected by another light receiver on the same side.
There has been a method of using a reflection type detector for detecting.

However, these detection methods have various limitations as described below depending on the case of measurement, and one method cannot be applied to all cases, so that they are most suitable for each measurement condition. There was a problem that the method had to be selected.

Such problems will be listed and described in the order of the first to third methods. Regarding the first method, the method using a bar magnet or reed switch has the simplest structure,
There is an advantage that the cost can be the lowest. However,
Depending on the type of sample liquid to be measured, there is a liquid containing a small amount of fine iron powder in the liquid, or a liquid in which a large amount of magnetic fine powder is suspended from the beginning such as a magnetic paint. In such a case, iron powder and magnetic powder are attracted and firmly adhered to the periphery of the falling weight 2, so that the gap between the inner surface of the measuring tube 1 and the outer surface of the falling weight 2 is clogged, and a normal viscosity measurement is performed. There was a serious drawback that the movement was disturbed and the measurement could not be performed.

Regarding the second method, the electromagnetic detection method is more general than the above-mentioned first method, but the materials that can be used for the falling weight 2 are mostly limited to iron-based magnetic materials. For this reason, depending on the viscosity of the sample liquid, it may be desirable to slow down the drop speed, or the length of the drop weight is lengthened or the dimension difference between the inner diameter of the measuring tube and the outer diameter of the drop weight, that is, the gap dimension is narrowed. There is no other means. In this case, it is difficult to arbitrarily change the drop weight length due to the length of the measuring tube and the limit of the detector arrangement interval L. On the other hand, if the drop weight outer diameter is increased and the interval dimension is narrowed. However, since the particulate foreign matter suspended in the liquid interferes with the free fall of the falling weight, there is a fatal problem that it is easily affected by the foreign matter in the liquid and impairs reproducibility.

The optical detection method of the third method can be used in a relatively wide range as long as the sample liquid to be measured has a property that is almost transparent, but the sample liquid is opaque like ink and paint. As a result, the dynamic range of the change in the amount of transmitted light is reduced, which makes the detection unstable.

The problem is that even when reflected light is used instead of transmitted light, the state of reflected light is unstable because the falling weight fluctuates and falls in a vertical measuring tube, and especially when the sample solution is opaque, There was a problem of unstable detection, more than the above-mentioned transmitted light type, such that reflected light from the falling weight could not be obtained.

[0018]

The present invention has been made in view of the above-mentioned many problems, and is constituted by the following structure and detection method as means applicable to all cases by one method. It proposes a falling ball type viscometer for process control characterized by the above.

First means: The measuring tube is not vertical but is a tilt measuring tube whose tilt angle is variable, and the falling object is a falling ball different from the above-mentioned falling weight.

Second means: As the material of the measuring tube, hard glass, which has good light transmittance and relatively good workability, is used because the light is used as a non-contact passage detecting means.

Third means: As falling balls, metal spheres having a large light reflectance from the surface of the sphere, sintered metal spheres, white ceramic spheres, opaque white glass spheres, and the like, and black ceramic spheres having a small light reflectance. , Opaque, black glass sphere, etc., the black and white spheres having different surface reflectances and the spheres having different material densities are appropriately selected and used according to the reflectance of the sample liquid and the specific gravity and viscosity of the sample liquid.

Fourth means: The outer diameters of these falling spheres are set to a certain size which is considerably smaller than the inner diameter of the measuring tube.

Fifth means: Non-contact passage detection of a sphere falling in the sample liquid in the measuring tube is performed by focusing on the generatrix of the tube which is in contact with the falling (falling) sphere on the inner wall of the inclined measuring tube. For example, a diffuse reflection type optical fiber type detector disposed at two positions above and below the outer side is used.

[0024]

In the falling ball type viscometer constructed as described above, when the falling ball 2 falls in the tilt measuring tube 1 while receiving the viscous resistance of the sample liquid, it falls as shown in FIG. 7-a. Sphere 2
Will fall while being guided along the lower surface side busbar 1a of the inclination measuring tube 1. At this time, even if the sample solution is opaque,
If there is a difference in reflectance between the sample liquid and the falling ball, the liquid film of the sample liquid is extremely thin at the contact point between the falling ball 2 and the inner wall surface of the tilt measuring tube 1 when observed from the arrow Y side in FIG. 7-a. So, Figure 7-
The contact point 2a of the falling ball 2 even from the outside of the inclination measuring pipe as shown in b
It can be clearly observed that the object moves as it falls.

As shown in FIG. 7, the diffuse reflection type optical fiber type detector which focuses the passage of the contact point 2a on the drop guide bus 1a on the inner surface of the inclination measuring tube 1 as shown in FIG. By arranging the contact points 2a at the upper and lower positions like 4a and 4b of -a, the contact point 2a always moves on the drop guide bus 1a, so that the passing of the contact point 2a of the falling ball can be detected stably and reliably. it can.

At this time, in the passage detection by the diffuse reflection type optical fiber type detector, a black sphere is used when the reflectance of the opaque sample liquid is high, and a white color is detected when the reflectance of the opaque sample liquid is low. By using the sphere of the system, it is possible to further improve the detection contrast of the contact point 2a for detection.

When it is desired to slow down the falling speed of the falling balls depending on the viscosity of the sample solution, various metal balls, ceramic balls,
In addition to being able to select and use spheres with significantly different material densities such as glass spheres, the tilt angle of the tilt measuring tube can be changed, so unlike the conventional drop weight type viscometer, the measuring tube inner diameter and drop The drop speed can be changed by orders of magnitude without making troublesome changes such as reducing the outer diameter of the weight and reducing the gap size. Therefore, if the outer diameter of the falling ball is set to a sufficiently small size with respect to the inner diameter of the measuring tube, the influence of foreign matter in the liquid can be reduced.

An application was filed on August 30, 1991 in order to return the falling ball dropped to the bottom of the tilt measuring tube to the upper end of the tilt measuring tube again and at the same time to replace the sample liquid inside the tilt measuring tube. There is an invention of a falling weight type viscometer for process control. This invention operates a pneumatic intermittent operation pump using a bellows integrally provided in the lower part of the tilt measuring tube to automatically aspirate the sample liquid in the tank and then flush the tilt measuring tube. It can be circulated and has a simple structure so that the required functions can be sufficiently achieved.

[0029]

EXAMPLE FIG. 1 shows an example of a viscometer having a configuration in which all of the above means are adopted. FIG. 1 is a sectional view. Reference numeral 1 is an inclination measuring tube, 2 is a falling ball, 4a is a fiber type light reflection type passage detector provided on the upper side of the inclination side constant tube, and 4b is a fiber type light reflection type passage detector also provided on the lower side of the inclination side constant tube. A detector, 5 is a pneumatic intermittent intermittent working pump having two check valves 5a and 5b, an air chamber 5c and a bellows 5d, and a coil spring 5e for return, and 6 is an electromagnetic for operating the pneumatic intermittent intermittent working pump 5. It is a valve.

In the falling ball type viscometer having the above structure, when the solenoid valve 6 is operated to release the air pressure in the air chamber 5c, the return coil spring 5e pushes down the bellows 5d. The sample solution in a tank (not shown) is sucked into the bellows 5d. Next, solenoid valve 6
When the excitation is turned off, air pressure is applied to the air chamber 5c.
When the bellows 5d is compressed, the sample liquid in the bellows 5d is
It is pushed out through the check valve 5b and the inclination measuring pipe 1 and returned to the tank. At this time, when the sample liquid flows through the tilt measuring tube 1, the falling ball 2 that has dropped to the bottom of the tilt measuring tube is
It is blown up to the upper end of the tilt measuring tube by the flow of the sample liquid, and is pressed against the stopper 1a provided at the upper end of the tilt measuring pipe while the sample liquid is flowing.

When the bellows 5d is compressed, the bellows 5d
When the bottom plate P is pressed against the stopper S, the bellows 5d cannot be displaced any further, so the inclination measuring tube 1
The flow inside stops instantly. By stopping this flow,
The falling ball 2 pressed against the stopper 1a starts falling in the sample solution. That is, the viscosity measurement is also started by the start of falling of the falling ball, and the time required for the falling ball 2 to fall is counted by the clock pulse due to the time difference when passing through the passage detectors 4a and 4b. This count value becomes a measured value corresponding to the viscosity of the sample liquid.

Next, when the solenoid valve 6 is excited again, the sample liquid is again sucked into the bellows 5d as described above. In this way, by repeatedly turning ON / OFF the excitation of the solenoid valve 6, intermittent suction circulation of the sample liquid and repeated measurement operation of the viscometer are performed.

In the above viscosity measuring operation, the inclination measuring tube 1
Inside, the falling ball 2 repeatedly blows up and falls in the sample solution. When the falling ball 2 falls into the sample solution at this time, even if the sample solution is an opaque sample solution that cannot use transmitted light, in the case of the falling ball type of the present invention, the falling ball 2 and the inclination measuring tube 1 By utilizing the fact that the movement of the contact point with the inner wall surface can be observed, it has become possible to optically detect the passage of a falling ball that has fallen.

Moreover, since the material density of the falling ball can be largely changed and the inclination angle of the inclined side constant tube can be changed, there is no trouble of changing the inner diameter of the measuring instrument or the outer diameter of the falling weight, and the falling ball can be changed. By simply selecting the type and setting the tilt angle, you can easily change the drop time significantly.

[0035]

Other Embodiments As another embodiment, as shown in FIG. 2, as the passage detector, a limited reflection type photodetector is used instead of the fiber type detector. In the figure, 7a,
Reference numeral 7b is a limited reflection photodetector, and 8a and 8b are LED phototransistors incorporated in the detectors.

In the falling sphere viscometer, the passing position of the falling ball is limited, and the contact point between the falling ball and the tilt measuring tube always passes on a fixed bus line. Photodetectors can be used.

Also in this method, if the surface texture of the falling ball is selected so that the moment of passing the contact point can be detected as a sufficient change in brightness, the passage can be detected with good contrast in the first embodiment. This is similar to the case of the diffuse reflection type optical fiber type detector described above.

[0038]

The effects of the present invention are as described in the following items. a) In the conventional drop weight type viscometer, the condition of the sample liquid to be inspected,
One type of viscosity because the applicable pass detector differs depending on various conditions of the sample liquid, such as the sample liquid being opaque, containing magnetic fine powder, or suspending particulate foreign matter. The viscometer of the present invention has an effect that it can be used in common even if there is such a difference in the sample liquid conditions, although it could not be dealt with by the meter.

B) Unlike the conventional drop weight type viscometer, since the gap size can be made large, there is an effect that it is unlikely to be affected by the particulate foreign matter suspended in the liquid.

C) Even if the sample liquid, which cannot be measured by the conventional drop weight type viscometer, is a highly corrosive liquid, it has high corrosion resistance such as hard glass for the tilt measuring tube and ceramic ball for the falling ball. Since a flexible material can be used, the most important element parts for viscosity measurement, namely the inner diameter of the inclined measuring pipe and the size of the falling ball.
There is also an effect that measurement can be performed while ensuring durability such as mass. As described above, there is an effect that the material selection range of the falling ball is particularly widened, and the range of possibility of adapting to the sample condition is widened.

D) By using an optical fiber type detector as the optical passage detector, by installing only the amplifier section in a non-hazardous area, it is possible to use it in a hazardous area as it is.

In the conventional drop weight type viscometer, even if a large number of drop weights having different sizes are selected, the range that can be dealt with by a wide range of sample liquid viscosity is narrow. If a meter is used, it is possible to prepare a falling sphere made of various materials having different densities, and selectively use the sphere, so that a wider viscosity range can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a falling ball type viscometer showing an embodiment of the present invention.

FIG. 2 is a sectional view showing a partial configuration of another embodiment of the present invention.

FIG. 3 is a cross-sectional view showing only a main part of a conventional drop weight type viscometer.

FIG. 4 is a graph showing a measurement point of a measurement clock pulse of a conventional drop weight viscometer.

FIG. 5 is a cross-sectional view of a falling weight type viscometer using a bellows, which the present inventor has already applied for.

6 is a cross-sectional perspective view showing an arrangement of the optical sensor of the present invention, and FIG. 6-a shows a case where a light transmission type detector is used.
b is the case of using a light reflection type detector.

FIG. 7 is a view showing the behavior of a falling sphere, FIG. 7-a is a side perspective view seen from the right side of an inclined measuring pipe, and FIG. 7-b is a front perspective view seen from the front of the measuring pipe; FIG. 7-c is a perspective view showing a cross section of the measurement tube cut at the portion where the sensor is arranged.

[Explanation of symbols]

1 Measuring tube 2 Falling ball 3 Bottom plate 4a, 4b Passage detector 5a, 5b Check valve 5c Air chamber 5d Bellows 5e Return coil spring 6 Solenoid valve 7a, 7b Limited reflection photodetector 8a, 8b In the detector, respectively Built-in LED, phototransistor 9a light source 9b light receiving element 10a projected light 10b reflected light

Claims (4)

[Claims] 1. A detector is provided at each of an upper middle portion and a lower portion of a cylindrical measuring tube filled with a liquid to be measured whose viscosity is to be measured, and a weight previously prepared inside the upper portion of the pipe is freely dropped into the liquid. Applying the principle of measuring viscosity by measuring the time difference of passing through the weight detected by the detectors provided at the top and bottom,
In addition, instead of holding the cylindrical measuring tube vertically, in a viscometer in which an intermittently operating bellows pump that operates by air pressure or an air pump that performs the same function as the above is integrally incorporated into the lower part of the measuring tube. The measuring tube is made of a transparent material, the weight is a sphere, and the detectors on the upper and lower parts are optical. A process control tumbler characterized by using a detector to make it possible to handle a wide variety of liquids to be measured by utilizing the characteristic that the tumbling sphere falls and falls along the lower bus bar of the measuring tube. Spherical viscometer. 2. Hard glass is used as a transparent material constituting the measuring tube according to claim 1. 3. The falling sphere according to claim 1, which is a metal sphere having a high light reflectance, a sintered metal sphere, a white ceramic sphere, an opaque white glass sphere, a black ceramic sphere, an opaque black glass sphere, or the like. It is selected and used according to the liquid reflectance, the same liquid specific gravity, and the same liquid viscosity. 4. The optical detector described in claim 1 is a diffuse reflection type optical fiber type detector or a limited reflection type photodetector arranged at two positions above and below the outside of the tilt measuring tube.