Precision Glass Capillary Viscometers

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PSL Rheotek glass viscometers are mouth blown from low-expansion borosilicate glass tubing in their glassblowing workshop in Essex. The precision bore used for the capillary section is held to the close tolerance of ± 0.01mm. Glass viscometers are clearly marked with timing lines and other inscriptions as well as a unique serial number. A glass bridge is provided to give additional strength and the finished instrument is fully annealed.


Perfect smoothness
The most important feature of quality viscometer is the smoothness of the inside surface. The properties of the inside surface of the viscometer determine the flow of the sample. A smooth surface with a soft curve leading from the viscometer tube into the capillary section provides the conditions for the undisturbed flow of the sample.

Quality materials
All PSL Rheotek Capillary Viscometers are made from low thermal expansion borosilicate glass tubing.


Best flow properties
Any irregularities in the interior surface of the glass may cause turbulence in the sample movement leading to irregular flow time determinations. This will show up as a difference between the first and the second flow time when measuring viscosity. For the best chance of getting the second flow time to agree, choose a PSL Rheotek Viscometer to measure viscosity.

Measuring Different Liquids
For measuring transparent liquids, use ASTM Ubbelohde viscometer. The constant of this viscometer is temperature independent. Designed with an air arm, which is open to atmosphere, the ASTM Ubbelohde Viscometers returns accurate results using an approximate quantity of sample. For measuring opaque liquids, use U-Tube reverse flow viscometer.

Certified at the highest level
All glass viscometers from PSL Rheotek are supplied complete with a UKAS (ISO 17025) Certificate of calibration, laboratory No. 0247. A copy of the scope of accreditation may be seen here. All certificates are fully traceable to the Master Viscometer Scale held at PSL Rheotek. Production tubes are calibrated directly against Master References in the on-site laboratory.

Products available include:

  • ASTM Ubbelohde
  • U-Tube Reverse Flow Viscometers
  • Cannon-Fenske Routine
  • Cannon-Fenske Opaque
  • Suspended-Level Viscometers, Shortened Form
  • Miniature Suspended-Level Viscometers
  • Cannon-Manning Vacuum Capillary Viscometer
  • Asphalt Institute Vacuum Capillary Viscometer
  • Modified Koppers Vacuum Capillary Viscometer
  • Vacuum System for bituminous binders
  • U-Tube Viscometers
  • Cannon Manning Semi-Micro Viscometers
  • Miniature U-Tube Viscometers
  • Zeitfuchs Cross-Arm Viscometers
  • Viscometer Baths and Chillers
  • Metal Viscometer Holders and Bench Stand
  • Digital Reference Thermometers
  • Plastic & Rubber Viscometer Holders

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Contact us today for more information   |    Tel: +353 (0) 87 343 1487 or +353 (0) 87 738 5011