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KSV Sigma703
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Sigma 703 - Digital Tensiometer
Sigma 703 is manually operated all-round tensiometer and it measures surface or
interfacial tensions of liquids by Du-Nouy or Wilhelmy plate method. The
instrument is designed to be used in industrial, educational and other multiple
user applications where a need for a tensiometer is occasional, work load is low
or the purchase budget is limited. Sigma's features large digital read out with
display memory and the ring correction values are automatically calculated.
Measuring range is 0 to 200 mN/m and accuracy 0.1 mN/m.
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Features:
- easy to use and sturdy construction
- uses Du-Nouy or Wilhelmy plate method
- large digital readout
- automatic calculation of ring correction values
- accurate electronic micro balance
Performance:
- surface and interfacial tension measurement of liquids
- absorption measurements
Specifications:
| Maximum sample weight |
25 g |
| Measuring range |
0-250 mN/m (0-250 dyne/cm) |
| Resolution |
0.1 mN |
| Stage operation |
manual precision lift stage |
| Vessel size |
70 mm or 50 mm diameter |
Accessories:
| T201 |
Thermostatic vessel for temperature control of the
sample liquid. A heat exchange vessel with water jacket type of
construction. Heating/cooling of the water jacket by external
bath/circulator. Fits glass sample vessels of 50 mm and 70 mm in
diameter (T104, T105.) Operable temperature range 0 to +80 C. (External
bath/circulator not included). |
| T104 |
Sample Vessel fireproof, diameter 70 mm, 5 pcs/box |
| T105 |
Sample Vessel fireproof, diameter 50 mm, 5 pcs/box |
| T106 |
Du Nouy ring Pt-Ir-ring made to DIN 53914-80 and
ASTM D 971 specifications. Packed in wooden box. |
| T107 |
Wilhelmy Plate, platinum plate with micro roughened
surface |
| T108 |
Ring re-form tool for straightening of disformed Du
Nouy ring. |
| T109 |
Sample holder for plates. For rigid plate like
samples. Max. sample thickness 3 mm. |
| T110 |
Sample holder for plates. For flexible plate like
samples. Max. sample thickness 3 mm. |
| T111 |
Sample holder for fibres. Single use aluminium tube
hanged from balance hook. 10 pcs/bag. |
Catalogue summary
Applications
surfactants, soaps detergents
emulsions
Pharmaceuticals
Paints&Coatings
Paper, Film & ink products
Cosmetics
Oils, lubricants,
Designed to be used in industrial, educational and other multiple user
applications, Sigma 703 offers a cost effective and accurate solution to routine
measurement of surface and interfacial tension of liquids. Its straight forward
operation and sturdy construction makes it so easy to use that even the
inexperienced user can successfully make accurate measurement.
What is surface tension?
Surface tension is the property of a liquid in contact with air that makes it
behave as if it was covered with a thin membrane under tension. The molecule
inside the liquid interact equally with other molecules, from all sides, whereas
the molecule at the surface is affected only by the molecule below it. Therefore
the molecules exposed to air behave differently and try to contract to the
smallest possible area. Surface tension is defined as the force acting over the
surface of the liquid per unit length of the surface perpendicular to the force.
Why measure surface tension?
Understanding the interactions in-between the surfaces plays vital role in
research of new surface-engineered materials and in development of products and
processes with better performance. With today's sophisticated surface
engineering technologies it is possible to modify nearly any liquid or solid
surface to fit an application.
Surface tension is an extremely sensitive indicator providing information on the
washability, wetting, emulsification, foaming and other surface related
processes. The progress of various chemical reactions and presence of solvents
or surfactants in a liquid systems can be monitored by surface tension
measurement. Surface tension also provides information about the quality of
water-repellent finishes, stability of emulsions, oxidation, polymerization etc.
For example; in the development of new detergents the measurement of surface
tension becomes a indispensable tool in optimizing the performance of the
detergent. Wetting of solids, for example textiles, becomes problematic when the
surface tension of the water is high. The cleaning power is weak if the water
can not penetrate deep into the structure of the fabric. The function of
detergent is to lower the surface tension of the water detergent solution and to
help the solution to thoroughly enter into the textile.
How to measure surface tension
Du Nouy ring method
The most common way of measuring the surface tension is with the Du Nouy ring
method. The method is named after the French physicist who developed it in the
late 1800's. The measurement is performed by a Tensiometer, an instrument
incorporating a precision micro balance, platinum-iridium ring with defined
geometry and a precision mechanism to vertically move sample liquid in a glass
beaker.
The ring hanging from the balance hook is first immersed into
the liquid and then carefully pulled up, by lowering the sample cup, trough the
surface of the liquid. The micro balance is recording on-line the force applied
on the ring while pulling through the surface. The surface tension is the
maximum force needed to detach the ring from the liquid surface.
Wilhelmy Plate method
The Wilhelmy plate method uses the same hardware as the ring method. In the
dynamic plate method the platinum-iridium plate with defined perimeter is hung
from the micro balance and the plate is immersed into the sample liquid. The
surface of the plate is micro roughened in order to give it optimum wetting
properties. The plate then is pulled through the surface of the liquid until the
maximum force is reached and the plate brakes away from the surface.
In the static plate method the dry unwetted plate
is lowered to the surface until its lower edge nearly touches the surface. At
this point the liquid "jumps" onto the edge and sides of the plate.
The liquid wets the plate perimeter and increases its total mass to some maximum
point which is proportional to the surface tension of the liquid.
Easy operation
The result of the measurement is displayed in large digit in the front panel.
The tarring knob is used to zero the instrument before measurement. The Sigma
703 is factory calibrated and there is no need to calibrate balance before use.
Ring or Wilhelmy plate measuring method is chosen from a mode selector.
The measuring probe either the ring or plate is lifted from
the liquid by manually lowering the measuring cup. A precision thumb wheel
provides steady vertical movement of the sample vessel.
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