Force Tensiometer – K20

The flexible tensiometer for basic quality assurance

Our Force Tensiometer – K20 is a robust, semi-automatic instrument for the precise measurement of surface tension and interfacial tension. Using the ring and plate method as the main tensiometric methods, it produces reliable measurements for the routine quality assurance of your surfactant solutions and interfacial processes.

Our K20 measures surface tension and interfacial tension based on the wetting force acting on a measuring probe. The instrument's precision force sensor and the measuring probes in the form of meticulously produced rings and plates ensure accurate and reproducible results. The density of liquids can also be measured very easily and precisely. The option of long-life battery operation, the integrated memory and the low weight of the instrument also enable our K20 to be used flexibly on site.

Simple, semi-automatic measurement

The simple manual operation of the sample stage and the large, illuminated sample chamber enable the sample to be quickly set up and positioned. When one of the pre-prepared measuring programs is started, the motorized sample stage moves to enable the measurement to be carried out conveniently and accurately. The speed and other measurement parameters can be adapted flexibly to suit. This enables the measuring sequence to be easily optimized for the upper or lower measuring range of surface and interfacial tension. The accuracy of the measurement is enhanced by the magnetically locking windshield which prevents the troublesome effect of air currents.

Equipment for flexible measuring conditions

The optional thermostat jacket for our K20 enables process conditions for temperatures between ‑10 and 100 °C to be simulated exactly. For example, this enables the addition of surfactant to be optimized for a particular technical process. With dispersions, an integral magnetic stirrer ensures that the sample is uniformly mixed before the measurement is carried out.

The measuring results, together with all important parameters and flexibly editable information relating to the measurement, can be transferred to our proven tensiometer software LabDesk. Alternatively, the report containing the results can be output to a printer at the press of a button.

Tasks and applications

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

Measuring methods and options

  • Surface tension using the ring and plate method
  • Interfacial tension using the ring and plate 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 90 °C, temperature measurement with internal sensor

K20 accessories

With accessories for our Force Tensiometer – K20, you can not only extend the scope of your instrument, but also adapt the measuring conditions exactly to suit your individual samples and requirements.

PL21 – Standard measuring probe for the Wilhelmy plate method

The PL21 is our proven plate geometry for measuring 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 free surface energy and therefore also the required excellent wetting properties. These are further optimized by the homogenously roughened surface of the plate. A high-quality protective box is provided for its safe storage.

A PLC21 version of the plate with a certificate from an independent testing institute is also available.

PL22 – Wilhelmy plate measuring probe for small sample volumes

The PL22 measuring probe enables measurement of the surface tension using the Wilhelmy plate method in the case of small sample volumes. It is the same size (wetted length) as our standard PL21 plate and is also ideally wettable being made of the same precision metal platinum, but it is rolled cylindrically so it requires a smaller 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.

RI21 – Standard measuring probe for the Du Noüy ring method

The RI21 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 the wetting are negligible. A high-quality protective box is provided for its safe storage.

An RIC21 version of the ring with a certificate from an independent testing institute is also available.

DE01 – Set for density determination of liquids

The DE01 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.
 

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.

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.

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

TJ1020 – Thermostat jacket with stirring function

The TJ1020 thermostat jacket equips your tensiometer for accurate temperature-controlled measurements of between
-10 and 100 °C. The jacket has quick-locks for fast connection to a liquid thermostat and is made of the excellent heat-conducting metal brass. The 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 also available from us.

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

CP0501 – Adjustment set for the force sensor

The CP0501 set includes an E2 calibration weight with a mass of 20 g with which the force sensor of your tensiometer can be reliably calibrated. The actual value for the mass measured by the force sensor is adjusted to the nominal value of the accurate calibration weight. The attached certificate from the German Calibration Service (DKD) indicates the high level of precision of the weight.

The set also includes a hook and force sensor adapter to facilitate easy attachment of the weight and a pair of tweezers to ensure the weight can be attached without soiling. A high-quality case is provided for safe storage of the set.

CP14 – Calibration set for the force sensor

The CP14 calibration set is available for regular calibration of your tensiometer. The set includes three E2 standard weights (0.2 g; 0.5 g; 1.0 g), which are certified in compliance with OIML R111. The provided certificate from the German Calibration Service (DKD) indicates the high level of precision of the weight.

A weighing pan on which the weights can be easily placed and a pair of tweezers to ensure the weight can be applied without soiling are also included in the set. A high-quality case is provided for safe storage of the weights.

PR0510/PR12/PR13 – Protocol printer for measurement data output

The protocol printer PR0510 enables fast and simple output of your measurement data with measurement parameters and freely selectable notes for the measurement. The printer is equipped with a serial data transmission cable, a roll of paper plus a color ribbon and can be put into operation immediately.


 

Replacement material is also available from us:

  • PR12: Set of 5 rolls of paper
  • PR13: Color ribbon

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.

SP1001 – Rechargeable spare battery for stand-alone operation

The integrated SP1001 battery has to be replaced occasionally if the instrument is operated independently of the mains. You can do this yourself or have it carried out by our technical support, e.g. during servicing of the instrument.