DE102016219832A1 - capillary - Google Patents

Abstract

The invention relates to a capillary rheometer comprising a measuring cell (11) with an inlet (6a) and an outlet (6b) for feeding and discharging a test mass into or out of the measuring cell (11), the measuring cell (11) being a capillary (11). 3, 3a, 3b) and wherein at the two ends of the capillary in each case a test piston (4a, 4b) is arranged, which is arranged displaceably relative to the ends of the capillary, and wherein at both ends in each case a pressure sensor (2a, 2b 2c, 2d) is arranged to measure the pressure in front of the respective ends of the capillary, wherein the test pistons (4a, 4b) are mechanically interconnected and are displaceable by means of a common drive.

Description

The invention relates to a capillary rheometer, comprising a measuring cell with an inlet and an outlet for feeding and discharging a test mass into and out of the measuring cell, wherein the measuring cell comprises a capillary and wherein a test piston is arranged at the two ends of the capillary, which is arranged displaceably relative to the ends of the capillary and wherein at the two ends in each case a pressure sensor for measuring the pressure in front of the respective ends of the capillary is arranged.

The invention further relates to a method for operating a capillary rheometer, wherein the capillary rheometer is provided with a measuring cell, comprising an inlet and an outlet for feeding and discharging a test mass into and out of the measuring cell, wherein the measuring cell is provided with a capillary and wherein at the two ends of the capillary in each case a test piston is arranged, which is arranged displaceably relative to the ends of the capillary and wherein at the two ends in each case a pressure sensor for measuring the pressure in front of the respective ends of the capillary is arranged.

High polymers are by far the most widely used materials which are used in innumerable applications. a. in the packaging industry, the construction industry, in the automotive, electrical and household industries up to the areas of the furniture industry and agriculture.

With known plastic molding process a variety of products and components made of different thermoplastic melts. Here, for example, initially present as granules thermoplastics are melted or extruded in extruder screws. These plastic melts to be processed behave viscoelastically. This means that in addition to the viscous properties of ideal liquids and elastic material properties appear. The processability of plastic melts is decisively influenced by these rheological properties.

Measuring instruments for determining rheological properties, so-called rheometers, are constructed either as rotary or capillary rheometers. Known rotational rheometers may, for example, be designed as a plate-plate or cone-plate system and measure in the linear and nonlinear viscoelastic region. In contrast, known capillary rheometers measure in a steady pressure flow, which is formed by the flow through a capillary or rectangular nozzle. However, this does not directly determine viscoelastic polymer properties in absolute physical quantities.

The results from the dynamic (oscillating) test on the rotation rheometer lead directly to the characterization of the material structure, while the data of the stationary test in the capillary rheometer describe the process behavior of the plastic melt in the subsequent processing (injection molding, extrusion, etc.).

This process of determining the rheological properties of plastic materials in the laboratory with two different devices and then transferring them to the process is problematic in two respects. On the one hand, properties are determined with two different measuring devices and measuring geometries, which can make the comparability and correlation of the measurement data thus obtained more difficult or adversely affect.

On the other hand, it is fundamentally problematic to transfer laboratory data one-to-one to the later process. Thus, for example, the thermal degradation of a polymer melt in the extruder (high thermal and mechanical loads) in the laboratory test can not be described or quantified. The goal is to quantify the rheological properties directly in the process.

Directly in the process, so-called online rheometers in capillary design are used to determine the melt index and the viscosity or their viscous properties. However, carrying out dynamic tests and thus determining the structural properties - derived from the viscoelastic material properties - of the processed material is not possible with online rheometers compliant with the process time.

The company STRATA technology Limited has announced a so-called "Multi Pass Rheometer MPR", which can measure both the dynamic and the stationary properties of a test mass. This is based on the publication "MR Mackley, RTJ Marshall and JBA Smeulders," The Multipass Rheometer ", J. Rheol. 39 (6) November / December 1995, 1293-1309 , The rheometer is only suitable for laboratory use. Here, a melt is brought into oscillation by a hydraulic drive. The rheometer can only be used up to a maximum of 200 ° C.

Other known rheometers are in the non-patent literature "MR Mackley, DG Hassell," The multipass rheometer a review ", J. Non-Newtonian Fluid Mech. 166 (2011) 421-456 , in the form of a product description for the device "ViscoSure" of the company PAC, http://www.paclp.com/process_analytics/viscosure , as well as in the non-patent literature "Rheological Testing Technique of High Polymers", A. Göttfert, E.-O. Reher, KGK 9/1996 page 609-615 described: In the non-patent literature MR Mackley, DG Hassell, "The multipass rheometer a review," J. Non-Newtonian Fluid Mech. 166 (2011) 421-456 a rheometer is shown, which is separated by two valves from a melt line. 1 shows such a rheometer. The rheometer also has two test punches, which are controlled by two synchronized servohydraulic motors. The test punches are arranged in a heated test channel segment with a centrally arranged test chamber. The test punches can either be moved back and forth to oscillate the test material either oscillating through the capillary, or rate-controlled in a direction of motion to produce a steady state flow. Before and after the capillary, a pressure sensor for measuring the pressure is arranged in each case. One of the disadvantages of this is that no defined rinsing operations, which are necessary for a perfect measurement process, are possible. In the worst case, the measuring cell is not rinsed in this arrangement. Also shown is a measuring chamber for optical tests.

In the product description for the device "ViscoSure" of the company PAC, http://www.paclp.com/process_analytics/viscosure is an online rheometer described for measuring asphalt and oil. The measurement takes place via an oscillating test punch, which is moved back and forth in a bore.

From the non-patent literature "Rheological Testing Technique of High Polymers, A. Göttfert, E.-O. Reher, KGK 9/1996 page 609-615 " a rheometer is known in which an oscillatory speed change is applied to a spinning pump, so that the stationary flow is superimposed on a dynamic flow.

It is therefore an object of the present invention to provide an on-line rheometer which can determine the properties of a test mass both dynamically and stationarily, and is also easy to produce and enables a reliable determination of the rheological properties of the test mass.

The invention solves the problem in a capillary rheometer, comprising an inlet and an outlet for feeding and discharging a test mass into or from a measuring cell, wherein the measuring cell comprises a capillary, and wherein in each case a test piston is arranged at the two ends of the capillary, which is arranged displaceably relative to the ends of the capillary and wherein at the two ends in each case a pressure sensor for measuring the pressure in front of the respective ends of the capillary is arranged, characterized in that the test pistons are mechanically interconnected and are displaceable by means of a common drive.

The invention also achieves the object in a method for operating a capillary rheometer, wherein the capillary rheometer is provided with a measuring cell, comprising an inlet and an outlet for feeding and discharging a test mass into or out of the measuring cell, wherein the measuring cell is provided with a capillary and wherein at the two ends of the capillary in each case a test piston is arranged, which is arranged displaceably relative to the ends of the capillary, and wherein at the two ends in each case a pressure sensor for measuring the pressure in front of the respective ends of the capillary is arranged, characterized in that the test pistons are mechanically connected to one another and displaced by means of a common drive.

One of the advantages achieved with this is that a particularly reliable measurement of both the stationary and the dynamic viscoelastic properties is made possible in a simple manner.

Further features, advantages and further embodiments of the invention are described below or are apparent therefrom:
Advantageously, the common drive takes place in the form of a, in particular electrically operable, eccentric drive. This is a simple and inexpensive and at the same time flexible drive possible.

The test pistons are expediently connected to one another and to the common drive by means of a highly rigid fork. On the one hand, this enables a highly synchronous movement of the test punches, at the same time enabling a highly synchronous oscillatory movement in an extremely cost-effective manner.

Advantageously, at least one sliding seal is arranged on at least one, preferably both, test pistons. This ensures a very high density and thus a reliable measurement.

Conveniently, in each case a valve for controlling the supply and discharge of the proof mass is arranged. This reliably controls the inflow and outflow from the measuring cell.

Advantageously, the at least two valves are formed by a common rotary valve. This provides a very inexpensive and at the same time reliable design for controlling the inflow and outflow of the proof mass.

Conveniently, the rotary valve is electrically and / or pneumatically or manually actuated. This is an easy and flexible way an operation of the rotary valve is possible.

Advantageously, a decoupling device for decoupling the measuring cell is arranged. By means of the decoupling device a reliable separation of the measuring cell from the process is possible, so that, for example, the system, ie. H. the measuring cell, regardless of the process pressure in a melt line or the extruder (process) can be rinsed.

Advantageously, the uncoupling device comprises at least one, preferably two spinning pumps and / or a throttle. This is a simple and reliable way a decoupling possible.

Advantageously, a second capillary is arranged, wherein at the two ends of the capillary each have a further pressure transducer for measuring the pressure in front of the respective ends of the second capillary is arranged and wherein the second capillary is arranged in the measuring cell, so that by means of the first and second capillary can be measured simultaneously dynamically and in stationary flow. Thus, the time for a determination of the rheological properties can be significantly shortened.

Conveniently, at least a third capillary is arranged, in which case a spinning pump is then arranged for each of these third capillaries. For example, several measurements of different materials or the same material can be carried out at the same time by means of a plurality of third capillaries. In the latter case, several measurements can then be combined to increase the measuring accuracy.

Advantageously, the respective spinning pump for each of the third capillaries is coupled to drive them with a further spinning pump or has a separate drive, which is synchronized with another spinning pump. One of the advantages achieved is that in a simple way the spinning pump are synchronized with each other.

Appropriately, the delivery rate of at least one spin pump, in particular on the speed controlled. This makes it possible to regulate the delivery rate in a simple and reliable manner.

Further important features and advantages of the invention will become apparent from the subclaims, from the drawings, and from associated figure description with reference to the drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Preferred embodiments and embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components or elements.

It shows

1 an already known rheometer;

2 Parts of a rheometer according to an embodiment of the present invention;

3 Parts of a rheometer according to an embodiment of the present invention;

4 Parts of a rheometer according to an embodiment of the present invention; and

5 Parts of a rheometer according to an embodiment of the present invention.

1 shows an already known rheometer. The rheometer 1 has a measuring cell 11 on, which is a capillary 3 having. In a linear arrangement at the two ends of the capillary 3 are test pistons 4a . 4b arranged in the direction 100 , So in the direction of the ends and away from each of them are movable. The end areas of the capillary 3 stand each one valve 5a . 5b in connection with a connection cable 6a . 6b can be added or removed via the proof mass.

2 shows parts of a rheometer according to an embodiment of the present invention.

In detail is in 2 a measuring cell 11 a rheometer 1 shown. The measuring cell 11 has an inlet 6a and an outlet 6b for a test mass to the environment, for example, for connection to an extruder or melt line. Downstream of the inlet 6a is a spinning pump 10 arranged by means of a motor 21 is drivable. Downstream of the spinning pump 10 is a valve 5a arranged and further downstream of the valve 5a is the inlet of a capillary 3 arranged. In the area of the entrance of the capillary 3 is a first pressure transducer 2 B for measuring the pressure before the inlet of the capillary 3 arranged. The same applies accordingly to the other end of the capillary 3 - Outlet of the capillary - on which a second pressure transducer 2a is arranged. In a linear arrangement to the longitudinal extent of the capillary 3 are two displacement pistons 4a . 4b arranged. The outlet of the capillary 3 is in turn via a valve 5b and continue one throttle 11 with the outlet 6b connected. The test pistons 4a . 4b are with a high stiff fork 9a . 9b connected by means of an Excenters 8th in turn, from a motor 22 is driven, is operable. The high stiff fork 9a . 9b provides a highly synchronous movement of the test piston 4a . 4b for sure. The movement of the test piston takes place here via an electric eccentric drive 8th . 22 , The test pistons 4a . 4b each have at least one, preferably two sliding seals 7a . 7b on to achieve a high density. The over the high stiff fork 9a . 9b coupled test piston 4a . 4b move through the eccentric drive 8th . 22 oscillating back and forth. Through a variable speed control of the eccentric motor 22 may be a defined frequency range for determining the known physical variables of the viscoelasticity of a test mass in the capillary 3 be enabled.

Furthermore, the measuring cell 11 - As stated above - two valves 5a . 5b for the inlet and outlet of the test mass or melt into or out of the measuring cell 11 on, manually, electrically or pneumatically by means of a motor 21 can be operated. These valves 5a . 5b are here preferably as a uniaxial rotary valve 12 executed in a connecting hole. The rotary valve 12 allows in a first position A a direct flow through the measuring cell 11 , whereby there the material exchange takes place. In another position B is the measuring cell 11 from inlet and outlet 6a . 6b decoupled - now the melt rests - and is bypassed in the bypass via the connecting hole. In position B, the oscillating movement of the two test pistons takes place 4a . 4b , and thus the determination of viscoelastic characteristics.

The measuring cell 11 further points the already mentioned spinning pump 10 on top of that, the measuring cell 11 decoupled from the process, so that the measuring cell can be purged regardless of the process pressure in the melt line or the extruder (process). In position A will flow through the capillary 3 at constant speed of the spinning pump 10 the pressure difference between the pressure transducers 2a . 2 B measured to determine the steady state viscosity. Through the throttle 11 at the outlet 6b a constant filling pressure is achieved. The throttle 11 fulfilled, comparable to the spinning pump 10 in the input, the output-side decoupling of the measuring cell 11 from the process. By means of variable pump speeds and corresponding pressure drops, the stationary viscosity function can thus be determined in a given shear rate range.

3 shows parts of a rheometer according to an embodiment of the present invention.

In 3 is essentially a measuring cell 11 according to 2 shown. In contrast to the measuring cell 11 according to 2 has the measuring cell 11 according to 3 a second capillary 3b on. At the inlet and outlet of the second capillary 3b are each another pressure sensor 2c . 2d arranged to measure the pressure. By means of the valves 5a . 5b or the rotary valve 12 can the second capillary 3b fluidic with the inlet 6a or the outlet 6b get connected. By means of the second capillary 3b and the two pressure sensors 2c . 2d before or after the second capillary 3b can in position B of the rotary valve 12 , simultaneously, dynamically via first capillary 3a and in steady flow over the second capillary 3b be measured. In the case of the second capillary 3b is designed identically as the first capillary 3a , During the flushing process, the measured variable of the second capillary 3b be used to safely stop the flushing while checking whether the bore of the first capillary 3a not added with degraded material. This effect - z. B. deposits in the capillary 3a . 3b - Can be due to the longer residence time of the test mass / the material in this part of the measuring cell 11 occur. In the case that the system has more than one or even more capillaries, one additional spin pump can be arranged for each of these additional capillaries. The further spinning pump (s) is (are) either mechanically coupled to the already existing spinning pump (s) or each equipped with a further drive whose speed coincides with the speed of the drive 21 the first spinning pump 10 is synchronized.

4 shows parts of a rheometer according to an embodiment of the present invention.

In 4 is essentially a measuring cell 11 according to 2 shown. In contrast to the measuring cell 11 according to 2 has the measuring cell 11 according to 4 instead of the throttle 11 a second spinning pump 10b on, by means of another motor 23 is drivable.

By means of the second spinning pump 10b with engine 23 , the material / proof mass can be returned to the process (melt line or extruder) via the outlet 6b be encouraged. Through the second spinning pump 10b in the area of the outlet 6b the system is independent of the process pressure and a constant feeding pressure can also be achieved. This second spinning pump 10b either has - as mentioned - a separate engine 23 on that with the engine 21 the first spinning pump 21 is synchronized or mechanically coupled via a common drive shaft.

5 shows parts of a rheometer according to an embodiment of the present invention.

In 5 is essentially a measuring cell 11 according to 3 shown. In contrast to the measuring cell 11 according to 3 has the measuring cell 11 according to 5 instead of the throttle 11 a second spinning pump 10b on, by means of another motor 23 drivable is analogous to the embodiment in 3 ,

Analogous to the embodiment according to FIG 3 here is the further capillary 3b and the at least two other pressure transducers 2c and 2d in front of and behind the second capillary 3b arranged to be simultaneously, dynamically via first capillary 3a and in steady flow over the second capillary 3b to be able to measure. In the event that the system with more than one further capillary is thus three or more capillaries, in each case one further spinning pump can have in the feed bore of the measuring arrangement or measuring cell 11 to be ordered.

The second spinning pump 10b is either mechanical with the already existing first spin pump 10a with engine 21 coupled or with another drive 23 equipped, whose speed with the speed of the drive 21 the first spinning pump 10a is synchronized. Alternatively, the pressure after the second capillary 3b measured via the fourth pressure sensor 2d about the speed of the spinning pump 10b be controlled in the outlet to avoid possible foaming of the test mass during the measurement process

• 1. Eine Messzelle mit linearer Kolbenanordnung von zwei gegenüberliegenden Kolben, die über eine hochsteife Gabel in der Bewegung synchronisiert sein können • Die Bewegung der Kolben kann über einen Exzenterantrieb erfolgen. • Die Stempel können mindestens je eine Gleitringdichtung aufweisen. • Die Stempel können sich oszillierend hin und her bewegen.
• 2. Die Messzelle kann an den Ausgängen zwei Ventile, bzw. einen Drehschieber, elektrisch oder pneumatisch angesteuert aufweisen. • Die Ventile/Drehschieber können mindestens zwei Stellungen, eine Durchgangsstellung und eine Stellung zum Umströmen der Messstelle aufweisen. • Die Anordnung kann eine Spinnpumpe in der Zuführleitung aufweisen. • Die Spinnpumpe kann ein Spülen der Kapillare ermöglichen. • Hierdurch kann die Messzelle vom externen Prozessdruckabgekoppelt werden. • Es kann eine Messung der stationären Viskosität während des Spülvorgangs erfolgen.
• 3. Die Anordnung kann eine Drossel in der Schmelzerückführung aufweisen und es kann ein stationärer Fülldruck erreicht werden.
• 4. Alternativ oder zusätzlich zur Verbindungsbohrung zwischen Ein- und Auslass im Ventil/Drehschieber kann die Anordnung mindestens eine weitere Kapillare mit mindestens zwei Druckaufnehmern aufweisen. • Es kann simultane Messung von stationärer und dynamischer Viskosität erfolgen. • Es kann Überprüfung des Spülvorgangs durch Vergleich der Viskosität von erster Kapillare und zweiter Kapillare bei identischer Kapillarengeometrie erfolgen. • Jede weitere Kapillare kann über eine separate Spinnpumpe versorgt werden, angetrieben über – gleichen Antriebsschaft und/oder – synchron zur Messpumpe arbeitender Motor.
• 5. Alternativ zur Drossel kann die Anordnung eine weitere Spinnpumpe zur Rückführung des Materials in den Prozess aufweisen und eine • Messzelle unabhängig vom Prozess und einen • konstanten Fütterdruck bereitstellen, wobei diese • angetrieben über – gleichen Antriebsschaft und/oder – synchron zur Messpumpe arbeitender Motor mit mindestens gleichem spezifischen Volumen.
• 6. Alternativ zur Verbindungsbohrung zwischen Ein- und Auslass im Ventil kann die Anordnung, bei der mindestens eine Spinnpumpe im Auslass vorhanden ist, mindestens eine weitere Kapillare mit mindestens zwei Druckaufnehmern aufweisen. • Es kann eine simultane Messung von stationärer und dynamischer Viskosität erfolgen. • Es kann eine Überprüfung des Spülvorgangs durch Vergleich der Viskosität von erster Kapillare und zweiter Kapillare bei gleicher Kapillarengeometrie erfolgen. • Es kann eine Regelung des Druckes nach der zweiten Kapillare über die Drehzahl im Falle, dass eine zweite Spinnpumpe im Rückförderstrom mit separatem Antrieb angeordnet ist. • Jede weitere Kapillare kann über eine separate Spinnpumpe versorgt werden und kann angetrieben werden über – gleichen Antriebsschaft oder – Synchron zur Messpumpe arbeitenden Motor.

In summary, in one or more embodiments, the present invention provides a test apparatus for determining the dynamic and stationary rheological data in the continuous process. The tester can according to at least one of the following points 1.-6. be trained:

• 1. A measuring cell with a linear piston arrangement of two opposing pistons, which can be synchronized via a highly rigid fork in the movement • The movement of the pistons can take place via an eccentric drive. • The punches can have at least one mechanical seal each. • The stamps can oscillate back and forth.
• 2. The measuring cell may have two valves, or a rotary valve, electrically or pneumatically actuated at the outputs. • The valves / rotary valves can have at least two positions, a passage position and a position for flowing around the measuring point. The arrangement may have a spinning pump in the supply line. • The spinning pump can allow flushing of the capillary. • This allows the measuring cell to be disconnected from the external process pressure. • It is possible to measure the stationary viscosity during the rinsing process.
• 3. The arrangement may have a throttle in the melt return and it may be a stationary filling pressure can be achieved.
• 4. Alternatively or in addition to the connection bore between the inlet and outlet in the valve / rotary valve, the arrangement may have at least one further capillary with at least two pressure transducers. • Simultaneous measurement of steady state and dynamic viscosity can be made. • It is possible to check the rinsing process by comparing the viscosity of the first capillary and the second capillary with identical capillary geometry. • Each additional capillary can be supplied by a separate spinning pump, driven by the same drive shaft and / or by a motor operating synchronously with the metering pump.
• 5. As an alternative to the throttle, the assembly may include a further spinning pump for returning the material to the process and providing a measuring cell independent of the process and a constant feeding pressure, this being driven by the same drive shaft and / or motor operating synchronously with the metering pump with at least the same specific volume.
• 6. As an alternative to the connection bore between inlet and outlet in the valve, the arrangement in which at least one spinning pump is present in the outlet, at least one further capillary having at least two pressure transducers. • Simultaneous measurement of steady-state and dynamic viscosity can be performed. • It is possible to check the rinsing process by comparing the viscosity of the first capillary and the second capillary with the same capillary geometry. • It can be a regulation of the pressure after the second capillary over the speed in the event that a second spin pump is arranged in the return flow with separate drive. • Each additional capillary can be supplied via a separate spin pump and can be driven via the same drive shaft or - synchronously with the metering pump motor.

In summary, the invention has, inter alia, the advantage that defined game operations are made possible and thus the reliability in the measurement of the rheological properties are significantly better. Another advantage is that easy synchronization of two pistons is made possible, without the need for a complicated control is necessary. Another advantage is that the invention is inexpensive and reliable at the same time.

Although the present invention has been described in terms of preferred embodiments, it is not limited thereto, but modifiable in a variety of ways.

LIST OF REFERENCE NUMBERS

1

capillary

2a, 2b, 2c, 2d

Pressure sensor / pressure sensor

3, 3a, 3b

capillary

4a, 4b

dolly

5a, 5b

Load cell

6a

Connection melting line / Extruders

6b

outlet

7a, 7b

poetry

8th

eccentric

9a, 9b

linkage

10, 10a, 10b

spinning pump

11

cell

12

rotary vane

13

throttle

20, 21, 22, 23

engine

100

Displacement direction / inspection stamp

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• "MR Mackley, RTJ Marshall and JBA Smeulders," The Multipass Rheometer ", J. Rheol. 39 (6) November / December 1995, 1293-1309 [0010]
• MR Mackley, DG Hassell, "The multipass rheometer a review", J. Non-Newtonian Fluid Mech. 166 (2011) 421-456 [0011]
• http://www.paclp.com/process_analytics/viscosure [0011]
• "Rheological Testing Technique of High Polymers", A. Göttfert, E.-O. Reher, KGK 9/1996 pages 609-615 [0011]
• MR Mackley, DG Hassell, "The multipass rheometer a review," J. Non-Newtonian Fluid Mech. 166 (2011) 421-456 [0011]
• http://www.paclp.com/process_analytics/viscosure [0012]
• "Rheological Testing Technique of High Polymers, A. Göttfert, E.-O. Reher, KGK 9/1996 page 609-615 " [0013]

Claims (14)

Capillary rheometer ( 1 ), comprising a measuring cell ( 11 ) with an inlet ( 6a ) and an outlet ( 6b ) for the supply and discharge of a test mass into or out of the measuring cell ( 11 ), the measuring cell ( 11 ) a capillary ( 3 . 3a . 3b ) and wherein at the two ends of the capillary in each case a test piston ( 4a . 4b ), which is arranged displaceably relative to the ends of the capillary, and wherein at both ends in each case a pressure sensor ( 2a . 2 B ; 2c . 2d ) is arranged to measure the pressure in front of the respective ends of the capillary, characterized in that the test pistons ( 4a . 4b ) are mechanically connected to each other and are displaceable by means of a common drive. Capillary rheometer according to claim 1, characterized in that the common drive in the form of, in particular electrically operable, eccentric drive ( 8th . 22 ) he follows. Capillary rheometer according to one of claims 1-2, characterized in that the test pistons ( 4a . 4b ) by means of a high stiff fork ( 9a . 9b ) with each other and with the common drive ( 8th . 22 ) are connected. Capillary rheometer according to one of claims 1-3, characterized in that at least one sliding seal ( 7a . 7b ) on at least one, preferably both, test pistons ( 4a . 4b ) is arranged. Capillary spectrometer according to one of claims 1-4, characterized in that in each case a valve ( 5a . 5b ) is arranged to control the supply and discharge of the proof mass. Capillary rheometer according to claim 5, characterized in that the at least two valves ( 5a . 5b ) by a common rotary valve ( 12 ) are formed. Capillary rheometer according to claim 6, characterized in that the rotary valve ( 12 ) is electrically and / or pneumatically or manually operable. Capillary rheometer according to one of claims 1-7, characterized in that a decoupling device ( 10a . 10b ) for decoupling the measuring cell ( 11 ) is arranged. Capillary rheometer according to claim 8, characterized in that the decoupling device ( 10a . 10b . 11 ) at least one, preferably two, spinning pumps ( 10a . 10b ) and / or a throttle ( 13 ). Capillary rheometer according to one of claims 1-9, characterized in that a second capillary ( 3b ) is arranged, wherein at the two ends of the second capillary ( 3b ) each another pressure transducer ( 2c . 2d ) for measuring the pressure in front of the respective ends of the second capillary ( 3b ) and wherein the second capillary ( 3b ) so in the measuring cell ( 11 ) is arranged so that by means of the first and second capillary ( 3b ) can be measured simultaneously dynamically and in stationary flow. Capillary rheometer according to one of claims 1-10, characterized in that three or more capillaries are arranged, in which case a spinning pump is then arranged for each of these capillaries. Capillary rheometer according to claim 11, wherein the respective spinning pump is coupled for each of the capillaries to drive them with another spin pump or has a separate drive, which is synchronized with another spinning pump. Capillary rheometer according to one of claims 1-12, characterized in that the delivery rate of at least one spinning pump ( 10a . 10b ), in particular on the speed of which is controllable. Method for operating a capillary rheometer ( 1 ), wherein the capillary rheometer with a measuring cell, comprising an inlet ( 6a ) and an outlet ( 6b ) for the supply and removal of a test mass into or out of the measuring cell ( 11 ), the measuring cell ( 11 ) with a capillary ( 3a ) and wherein at the two ends of the capillary ( 3a ) a test piston ( 4a . 4b ), which is relative to the ends of the capillary ( 3a ) is arranged displaceably, and wherein at both ends in each case a pressure transducer ( 2a . 2 B ) to measure the pressure in front of the respective ends of the capillary ( 3a ), characterized in that the test pistons ( 4a . 4b ) are mechanically connected to each other and by means of a common drive ( 8th . 22 ) are moved.

Images