CSC Scientific Company

DuNouy Tensiometer

DuNouy Tensiometer• The CSC DuNouy Tensiometer helps

decorative and hard chrome platers meet the EPA regulations on chromium emissions.

The regulations state that there is a direct relationship between surface tension and chromium emission.

• The interfacial tension test is the most valuable single test that can be used to evaluate a turbine oil.

It is generally agreed that when the interfacial tension is between 15 and 20 dynes/cm, deposits may or may not be forming in the system.

•The Precision DuNouy Tensiometer measures upward surface tension.

DuNouy Tensiometer

Both units are delivered complete with platinum iridium ring and carrying case allowing you to get rapid measurement in 15 to 30 seconds right out of the box.

•The Interfacial DuNouy Tensiometer measures both upward and downward forces.

Applications

•paints, coatings and inks;

•chrome, nickel, and brass plating;

•soap;

•surfactants;

•emulsions;

•crude and transformer oils.

•universities and technical centers as an

important instrument for scientific studies.

•RAPID MEASUREMENT Ring method allows readings to be made in 15-30 seconds

•DIRECT READING Equipped with circular scale in dyne/cm - No Calculations needed.

•REPRODUCTIBLE RESULTS Accurate readings can be reproduced within +/- 0.05 dyne/cm

•PORTABILITY Compact unit comes with a carrying case for easy transport

•STABILITY Mounted on a cast tripod support with convenient leveling screws

DuNouy Tensiometer

Intermolecular forces as they effect Interfacial Tension

A layer of molecules on an oil’s surface are in contact with air (Fig 1) the molecules are more strongly attracted from below because the molecules in the air are further apart (the attraction is inversely proportional to the distance between the molecules).

A similar imbalance occurs between two immiscible liquids such as oil and water; in this case the phenomenon is called

interfacial tension.

Measurement Techniques

The most common method of measuring surface /interfacial tension

In the test (Figures 2 and 3), the force required to lift a horizontal platinum wire ring away from the oil’s surface is measured either directly (surface tension) or at an oil/water interface (interfacial tension).

The unit of measure for surface tension is dynes per centimeter

(equal to mN/m).

Interfacial Test

Comparing Oil Oxidation Sensitivity Using Interfacial Tension and Neutralization

Number

When oils oxidize they form soluble and insoluble hydrophilic compounds. Many of these compounds can alter the IFT of a lubricant long before there is any noticeable change in acid number or viscosity (Fig 4).

Different ways Surface Tension is Measured

Wilhelmy Plate

DuNouy Ring

How is Surface Tension Measured?

CSC Rings

CSC DuNouy Tensiometer

DuNouy Precision TensiometerHow it works

DuNouy Interfacial TensiometerHow it works