Force Tensiometer – K11

The precision instrument for quality assurance

Our Force Tensiometer – K11 is a precision and fully automatic instrument for the reliable measurement of surface tension and interfacial tension. With its high-quality components and simple operation, the K11 assists in the quality control and optimization of surfactant solutions and interfacial processes.

Quality components for reliable results

Our Force Tensiometer – K11 measures the surface tension and interfacial tension based on the force which acts when a measuring probe is wetted. The instrument features a high-quality force sensor which ensures accurate results and high reproducibility. In the interests of precision, the probes are also manufactured with highly accurate contours. Our instrument therefore provides equally reliable results for measurements carried out using the ringplate or rod method. The K11 also enables the density of liquids to be measured accurately. This method is particularly useful for measurements using the ring method, in which the density is used to calculate the surface tension from the force. Measuring density with our K11 saves the trouble of carrying out external measurements.

The sample stage of our K11 has a high position resolution and, if required, can be moved very slowly and carefully. This enables the force maximum in ring measurements to be determined with great accuracy, and therefore makes this method highly reliable. As an option, the stage can also be moved very quickly for setting up measurements rapidly. At the same time, the large, illuminated sample chamber helps when preparing the measurement. Magnetically locking glass swing doors shield the measurement from troublesome air currents.

Our K11 has the option of accurately controlling the temperature of the samples between -10 and 130 °C. This enables thermal process conditions to be simulated, for example to optimize the addition of surfactant for a particular production step. An additional, automatic stirring function ensures optimum mixing of dispersions before measuring.

Easy and intuitive touch panel operation

Intuitive operation by means of a special touch panel is a unique feature of our K11. Our touch panel has intelligent, programmable measuring sequences for all the methods incorporated. A simple touch of a finger starts the measuring programs, the parameters of which we have optimized for the most frequent situations. The accurately controlled sequences guarantee that the measuring conditions are highly repeatable. However, the parameters can also be flexibly adjusted and applied as a user-defined standard. A reliable measuring sequence for the standardized quality assurance of transformer oils in accordance with ASTM D‑971 is also included.

Our touch panel software manages the measuring results in a transparent structure. The touch panel also has a vast working memory and convenient, fast access to a very large number of storable measurements. It is also capable of producing comprehensive and clear measurement reports, sending them directly to a printer or saving them in the widely used Microsoft XPS format. Data can simply be copied from the touch panel to a USB flash drive for easy export.

Tasks and applications

  • Determination of the effectiveness of wetting media
  • Checking the surfactant content in solutions below the critical micelle concentration (CMC)
  • Measurement of interfacial tension for the quality assurance and optimization of emulsifiers
  • Decomposition product content in oils according to ASTM D‑971.
  • Tank clearance and cleaning validation in the foodstuffs industry

Measuring methods and options

  • Surface tension using the ring, plate and rod method
  • Interfacial tension using the ring, plate and rod method
  • Surface tension and interfacial tension using the ring tear-off method
  • Testing of transformer oils in accordance with ASTM D‑971
  • Measuring the density of liquids
  • Measurement from -10 to 130 °C, temperature measurement with internal sensor

K11 accessories

With the comprehensive range of accessories for our Force Tensiometer – K11, you can not only extend the scope of your instrument, but also adapt the measuring conditions exactly to suit your individual samples and requirements.

Measuring probes

There are a number of special probes available for your Force Tensiometer – K11, in addition to the standard probes for the Du Noüy ring method and the Wilhelmy plate method. These enable analyses using only small sample volumes and expand the spectrum of methods to include measurement of liquid density.

 

PL01 – Standard measuring probe for the Wilhelmy plate method

The PL01 is our proven plate geometry for measuring the surface and interfacial tension using the Wilhelmy plate method. The dimensions of the plate comply exactly with the form specified in international standards and thus enable a high level of repeatability for the analyses. As the plate is made of the precious metal platinum it has an extremely high surface free energy and therefore also the required excellent wetting properties. These are further optimized by its homogenously roughened surface.

A simple clamping mechanism allows especially fast insertion of the plate. Its safe storage is assured through a high-quality protective box provided.

A PLC01 version of the plate with a certificate from an independent testing institute is also available.

PL02 – Wilhelmy plate measuring probe for small sample volumes

The PL02 measuring probe enables measurement of the surface tension with the Wilhelmy plate method in the case of small sample volumes. It is the same size (wetted length) as our standard PL01 plate and is also ideally wettable being made from the same precious metal platinum, but it is rolled cylindrically so it only requires a small surface area of the liquid. A high-quality protective box is provided for safe storage of the plate.

The scope of delivery of the rolled plate also includes a measuring vessel that can be used flexibly for different sample volumes: The hollow has a capacity of 5 mL and the vessel has concentric rings on its underside that can be filled with up to 1.2 mL or up to 0.2 mL.

PL03 – Rod-shaped probe for measurements with the Wilhelmy method

The rod-shaped probe PL03 can be used as an alternative to the rolled PL02 for measuring the surface tension using theWilhelmy method with small sample volumes. Thanks to its small diameter it is possible to carry out measurements in small vessels, but unlike the PL02 it also enables measurement of the interfacial tension. The rod is made of the ideally wettable precious metal platinum. A high-quality protective box is provided for its safe storage.

The scope of delivery of the rod also includes a measuring vessel that can be used flexibly for different sample volumes. The hollow has a capacity of 5 mL and the vessel has concentric rings on its underside that can be filled with up to 1.2 mL or up to 0.2 mL.

RI01 – Standard measuring probe for the Du Noüy ring method

The RI01 ring is our high-precision standard measuring probe for surface and interfacial tension using the Du Noüy ring method. The wire ring made of a platinum-iridium precious metal alloy is ideally wettable; the hardness of the iridium makes the measuring probe especially robust. The ring geometry is only connected to the shaft at two junctures, so that any disturbing influences on wetting are negligible.

A simple clamping mechanism allows especially fast insertion of the ring. Its safe storage is assured through a high-quality protective box provided.

An RIC01 version of the ring with a certificate from an independent testing institute is also available.

RI02 – Du Noüy ring measuring probe for small sample volumes

The special measuring probe RI02 is used for measuring the surface tension with the ring method where only small sample volumes are available. Measurements with volumes as of 1 mL are possible thanks to the reduced diameter of the ring.

Like the standard RI01 ring, the RI02 is also made of a platinum-iridium alloy so its combines ideal wettability with the necessary metal hardness. Its design with only two contact points between the ring and the shaft and its shape accuracy ensure a high level of precision. A special vessel for small sample volumes is included in the scope of delivery as well as a high-quality protective box in which it can be safely stored.

DE0601 – Set for density determination of liquids

The DE0601 set enables accurate determination of the density of Newtonian liquids using the buoyancy force on an immersion body (Archimedes’ principle). The materials – silicon crystal for the immersion body and platinum-iridium for the accompanying holder – are inert and can be used for virtually all liquids with a maximum density of 2.3 g/cm3. A high-quality protective box is provided for safe storage of the set.

Sample vessels and matching adapters

You can create the ideal conditions for the analysis of your special samples with the aid of a selection of sample vessels in various sizes and shapes and made of different materials.

 

SV30/SV20/SV10 – Glass sample vessels with different sizes

The SV30/SV20/SV10 fire-proof glass sample vessels are the standard vessels for analyses carried out with our tensiometers. Easy to clean and resistant to most chemicals, they are suitable for virtually all test liquids. The vessels come in different sizes to optimize the measurement of different sample volumes.


 

The following glass vessels are available from us:

  • SV30: set of 6 sample vessels with an outer diameter of 98 mm (temperature-controlled measurements are possible with the special TJ34 thermostat jacket)
  • SV20: set of 6 standard vessels with an outer diameter of 70 mm, that are an exact fit for the standard thermostat jacket of our tensiometers
  • SV10: set of 6 sample vessels with an outer diameter of 50 mm for medium sample volumes

SV21/SV11/SV01 – PTFE sample vessels in different sizes

Our sample vessels SV21/SV11/SV01 made of PFTE are used if glass is not suitable as a sample vessel material. Due to the fact that their surfaces are difficult to wet, the PTFE vessels are easy to clean and therefore well suited for liquids that cause severe soiling such as inks, varnishes or adhesives. The PTFE vessels also optimize the analysis of surfactants that adsorb strongly on glass.


The following PTFE vessels are available from us:

  • SV21: vessels with an outer diameter of 70 mm, that are an exact fit for the thermostat jacket of our tensiometers
  • SV11: vessels with an outer diameter of 50 mm for medium sample volumes
  • SV01: special sample vessel for the smallest sample volumes. The SV01 is included in orders for a RI02/RI0902, PL02/PL0902 or PL03/PL0903 special probe, but can also be ordered separately.

We offer matching adapters for the SV11 and SV01 for positioning the sample vessel centrally in the thermostat jacket of the tensiometer.

SV26/SV12 – Cover plates for sample vessels during measurement

During measurement the SV26/SV12 cover plates ensure reduced heat exchange with the surroundings as well as constant measuring temperatures with temperature-controlled samples. In addition, the cover plates reduce evaporation of the sample, which in turn optimizes the accuracy of the analysis in the case of long-term measurements and volatile substances.



The following cover plates are available from us:

  • SV26: for sample vessels with a diameter of 70 mm
  • SV12: for sample vessels with a diameter of 50 mm

SV13 – Disposable aluminum sample vessel

Liquids that cause severe soiling or that cure can be analyzed trouble-free with the aid of the SV13 disposable sample vessel. The vessel has an outer diameter of 50 mm and can hold 20 mL of a sample. The SV13 is available in sets of 100 vessels.

We also offer a matching adapter that positions the sample vessel centrally in the thermostat jacket and ensures optimum temperature control.

TJ22/TJ23/TJ24 – Thermostat jacket adapters for small sample vessels

The thermostat jacket of our tensiometers is designed for standard sample vessels with a diameter of 70 mm. The TJ22, TJ23 and TJ24 adapters are available for various smaller sample vessels. The adapters are made of the good heat-conductive metal aluminum, thus ensuring even temperature control of the sample. The adapters also make it easier to position the sample vessel in the center of the measuring instrument.


The available adapters are intended for the following sample vessels:

  • TJ22 (on the left in the picture): adapter for the SV10 sample vessel (50 mm outer diameter)
  • TJ23 (in the middle): adapter for the SV01 sample vessel for small sample volumes
  • TJ24 (on the right in the picture): adapter for the SV13 disposable sample vessel

Equipment for controlling temperature and gas atmosphere

A comprehensive range of accessories for carrying out measurements at defined temperature and gas atmosphere to accurately simulate the environmental conditions for your product or process or to carry out analyses of samples that are sensitive to oxygen.

 

TJ0524 – Thermostat jacket with stirring function

The TJ0524 thermostat jacket equips your tensiometer for temperature-controlled measurements of between -10 and 130 °C. The jacket has quick-locks for fast connection to a liquid thermostat and is made of the excellent heat conductor brass. An integrated temperature sensor ensures continuous communication of the temperature inside the jacket. The induction-based magnetic stirrer of this accessory is regulated via the control pad of the measuring instrument and enables quick mixing of solutions and dispersions.

Suitable thermostats are available from us.

TP0511/TP0512 – Temperature sensors for measurements with/without gas temperature controlled jacket

The TP0511 and TP0512 are highly accurate temperature sensors which can be used flexibly with your instrument. Thanks to the large measuring range at 0.1 °C precision, the sensors measures room temperature just as reliably as the working temperature of our accessories for temperature control. Measurement is carried out immediately at the sensor tip, thus reproducing the actual conditions directly at the solid or in the liquid sample. Our software links the temperature to the current analysis results.

Use of the sensor types:

  • TP0511 (top photo): Sensor set for the combination with a gas temperature controlled jacket TJ20
  • TP0512 (bottom photo): Sensor set for the standard setup of the tensiometer

TJ25 – Inert-gas hood

We have developed the TJ25 inert-gas hood to enable measurements of oxygen-sensitive substances. The TJ25 is equipped with a connection for inert gas and is attached to the thermostat jacket of the tensiometer in a few quick steps. The two-part hood ensures the lowest possible gas exchange with the surroundings.

TJ34 – Special thermostat jacket for large sample vessels

We have conceived the TJ34 thermostat jacket for temperature-controlled measurements of between -10 and 130 °C for large sample volumes. The jacket with its practical quick-lock connection accommodates the special SV30 sample vessel with its 98 mm outer diameter and is equipped with a powerful electromagnetic stirrer for effective thorough mixing of dispersions and viscous liquids. An integrated temperature sensor ensures continuous communication of the temperature inside the jacket.

Tools and aids

To assist you when working with your instrument, we offer helpful accessories for preparing and carrying out your measurements.

 

PA0910 – Wind shield hood

Strong air streams can have a negative impact on the high-precision force sensor of your tensiometer even when the measurement chamber is closed. The complete measuring instrument fits under the PA0910 wind shield hood, which can be used in order to optimize the measurement of setups under a lab hood, for example.

TO01 – Tool for adjusting distorted ring measuring probes

The delicate measuring probe for the Du Noüy ring method is easily bent if dropped or accidentally knocked rendering it unsuitable for the measurement. Our special TO01 tool can be used to restore the exact shape of the measuring element.

Alternatively our technical support also provides the re-alignment of deformed rings as a service or carries this out as part of the servicing of your instrument.