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Du Nouy Ring Surface Interfacial Tensiometer
Automatic surface tensiometer

Du Nouy Ring Surface Interfacial Tensiometer

Model: TEN201/TEN202, ASTM D1590, ISO 304, ISO 6295

TEN201/TEN202 Automatic interface tensiometer is an instrument that uses physical methods (such as the platinum ring method and platinum plate method) as an alternative to chemical analysis. It is mainly used to measure the surface and interfacial tension of liquids and is suitable for industries such as petroleum, chemical, power, and scientific research. Its indication error is ≤±1%, supports liquid-liquid interface testing, and is compatible with medium- to high-viscosity liquids (such as ink and paint) for tension variation analysis. 


Using the ring method under non-equilibrium conditions, it measures the surface tension of various liquids as well as the interfacial tension between mineral oil and water, reliably indicating the presence of hydrophilic oxides. With digital processing technology, the Du Nouy Ring Surface Interfacial Tensiometer offers faster response and improved anti-interference capabilities. The fully English interactive menu provides a simple and user-friendly interface. It is also equipped with a desktop thermal micro-printer that can automatically print test results.

General Introduction

TEN201/TEN202 Automatic interface tensiometer is an instrument that uses physical methods (such as the platinum ring method and platinum plate method) as an alternative to chemical analysis. It is mainly used to measure the surface and interfacial tension of liquids and is suitable for industries such as petroleum, chemical, power, and scientific research. Its indication error is ≤±1%, supports liquid-liquid interface testing, and is compatible with medium- to high-viscosity liquids (such as ink and paint) for tension variation analysis. 


Using the ring method under non-equilibrium conditions, it measures the surface tension of various liquids as well as the interfacial tension between mineral oil and water, reliably indicating the presence of hydrophilic oxides. With digital processing technology, the Du Nouy Ring Surface Interfacial Tensiometer offers faster response and improved anti-interference capabilities. The fully English interactive menu provides a simple and user-friendly interface. It is also equipped with a desktop thermal micro-printer that can automatically print test results.


Key Features

  • ​Working Principle
  • Standard
  • Structural Features
  • Application and Maintenance
  • Advantages

The interfacial tension meter mainly measures the surface tension of a liquid based on mechanical principles. It uses a sensor (such as a platinum plate or platinum ring) to come into contact with the liquid surface and then measures the maximum force required to detach the sensor from the liquid surface. This force represents the surface tension of the liquid.

During the measurement process, the interfacial tension meter first immerses the sensor into the liquid and then slowly pulls it out. At the moment the sensor detaches from the liquid surface, the instrument records the maximum force needed to pull out the sensor. The magnitude of this force directly reflects the liquid's surface tension.

Tension value Calculation: 

The interfacial tension meter uses high-precision internal sensors and a data processing system to accurately measure and record this maximum force. Then, using specific physical formulas, it converts this force into the surface tension value of the liquid. This value is usually expressed in milli-Newtons per meter (mN/m).

Manual surface tensiometerManual surface tensiometer
Platinum ringDu Nouy Ring method test


ISO 304 "Surface active agents -- Determination of surface tension by drawing up liquid films”

ISO 1409  " Plastics/rubber -- Polymer dispersions and rubber latices (natural and synthetic) -- Determination of surface tension by the ring method”

ISO 6295  " Petroleum products -- Mineral oils -- Determination of interfacial tension of oil against water -- Ring method “

ASTM D1417  "Standard Test Methods for Rubber Latices—Synthetic”

ASTM D1590  "Surface tension of industrial water and Industrial waste water”

ASTM D1331  "Standard Test Methods for Surface and Interfacial Tension of Solutions of Paints, Solvents, Solutions of Surface-Active Agents, and Related Materials”

ASTM D971  "Standard Test Method for Interfacial Tension of Oil Against Water by the Ring Method”

EN 14370  "Surface active agents. Determination of surface tension”

EN14210, OECD 115, ZB2025, GB/T 2960, GB/T 6541, GB/T 22237, GB/T 6541, GB/T 5549 etc.,

TEN201:

★Mainly consist in platinum ring, platinum torsional wire, differential sensor and data processing system etc.

★Easy to operate, high accuracy, auto calculate the liquid surface or interface tension value;  

★Digital display the load; Measuring tray auto up and down; Automatic one key adjust Zero point function;  

With peak value holding function; Automatic stop when the liquid film break; 

TEN202:         ★Mainly consist in platinum ring, platinum torsional wire, differential sensor and data processing system etc.

★Easy to operate, high accuracy, auto calculate the liquid surface or interface actual tension value;  

automatic calculate actual average tension value. 

★LCD display the load; Measuring tray auto up and down; Automatic one key adjust Zero point function;   

With peak value holding function; Automatic stop when the liquid film break;   

★ With peaking value holding indication function; 

with tray up and down indication function; 

with auto zeroing indication function.



Application Scenarios
This instrument is suitable for testing the tension at liquid-air interfaces (surface tension) or between different liquids (such as oil-water interfaces). In the power industry, it can be used for insulating oil quality monitoring; in the chemical industry, it can analyze solution properties; and in educational settings, it can intuitively demonstrate the forces between liquid molecules. Its purely mechanical structure makes it highly durable and easy to maintain, suitable for long-term use.

Operation and Maintenance
Before use, the level must be adjusted, and the platinum ring should be raised and lowered using the worm gear handle. After measurement, the platinum ring and sample container should be cleaned promptly, and the torsion wire should be stored in a relaxed state. The instrument does not require complex calibration; regular lubrication of the mechanical parts is sufficient to maintain performance. The specially designed lever frame structure effectively reduces operational errors.


Factors Affecting Measurement Accuracy

Although the interfacial tension meter is a high-precision measuring device, the measurement results may still be influenced by certain factors. For example, the liquid's temperature, purity, and the stability of the measurement environment can all affect the results. Therefore, when performing measurements, it is necessary to strictly control these variables to ensure the accuracy of the results.

1. The ring method testing uses a scientifically calibrated tension value. To eliminate errors caused by factors such as the shape and contamination of the platinum ring during ring method testing, the correction uses two standard substances instead of the gravitational method. When the platinum ring is used for a long time, causing shape changes or contamination that lead to testing errors, normal conditions can be restored simply by correction with standard substances, without the need to replace the expensive platinum ring.  
2. An integrated molded casing and precision direct drive mechanism are used, greatly improving the reliability and performance of the instrument. The drive mechanism operates without vibration, providing a physical basis for improving testing accuracy.  
3. The improved torque screw lever structure ensures that the magnetic core movement of the sensor follows a trajectory as close to a straight line as possible, ensuring the linearity of the test. 4. The instrument features an automatic stop function, allowing it to stop automatically when testing surface tension. After the test is completed, the lifting platform will automatically stop moving and display the tension value.  
5. The automatic averaging function can automatically calculate and display the average of multiple test results, reducing the workload and effort required from the operator.

Main Technical Specification

ModelTEN201TEN202
Measuring methodMotorized automaticMotorized automatic
Display typeDigital displayLCD screen
PrinterMicro printer
Measuring range0~200mN/m
Min. dial scale0.01mN/m
Platinum ring radius9.55mm
Platinum torsion wire0.3mm
Platinum ring perimeter length60mm
Sample tray stroke25mm
Glass cup volume60ml
Sample tray speed15 mm/min±2 mm/min
Dimensions400*250*350mm
Weight22kg
Power220V, 50HZ / 110V,60Hz


Main Accessories

ItemQuantity
Frame1   set
Platinum ring1   pc
Torsion wire1   pc
Pothook1   pc
Glass cup1   pc
500mg weight for calibration5   pcs
Power cord1   set
Micro printer1   set
Documents   (Manual, packing list, certificate)


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