Gravimetric Capillary Viscometer / Ubbelohde automatic
These viscometer models are further developments of manual glass capillaries. Depending on the model the filling, measuring as well as cleaning and drying are performed automatically. This eliminates operator reading errors and saves time. Most automated capillary viscometers operate with special capillaries that require less sample volume than the original types or that cover a wider measuring range. Such special capillaries do not fulfill the original standards but provide comparable precision. To enhance the performance further, there are also models available that test two or more capillaries simultaneously.
Temperature control is not limited to liquid thermostat baths. Precise temperature equilibration with liquid baths takes typically several hours. There are also electric systems available, especially for micro systems.
Many different capillaries (also referred to as 'tubes') are required to cover a wide viscosity range. Each capillary can cover a range defined by its minimum viscosity times factor 10 or times factor 100. For example, the standard 100-fold range for a specific Ubbelohde style capillary is 20 mPa.s to 2,000 mPa.s.
- Viscosity measuring range - several capillaries for the entire range: 0.3 mm2/s to 100,000 mm2
- Repeatability: < 1 %
- Temperature measuring range: -40°C (-40°F) to +200°C (392°F)
This range cannot be covered with one instrument alone - different models with additional equipment are required, depending on the desired measuring temperature range.
Sample throughput - max./hour for manual operation:
- less than 20, depending on sample type and measuring conditions
How temperature control is done depends on the viscometer model and temperature measuring range. Most models work with a liquid bath, but there are also instruments with electric heating and cooling available.
The sample volume depends on the capillary used.
- Typical sample volume for an automatic Ubbelohde style capillary: 25 mL
- Generally, automated viscometers are suitable for transparent and opaque samples.
|Viscometer type||Gravimetric Capillary Viscometer / automatic|
|Measuring principle||Gravimetric Capillary Viscometer|
|Calculated quantity||kinematic viscosity|
|Viscosity range - min||0.3 mm²/s|
|Viscosity range - max||100,000 mm²/s|
|Temperature - min||-40°C|
|Temperature - max||+200°C|
|Liquid bath thermostat required||yes|
|Temperature change with same filling||no|
|Sample volume - typical||25 mL|
|Solvent volume - typical||40 mL|
|Sample throughput - max / h||< 20|
|Measuring accuracy||< 1 %|
|Shear rate control||no|
|Shear rate calculation||no|
|Lab space||approx. 0.5 m²|
|Standards and norms||ISO 3104, ISO 3105, ASTM D 445, ASTM D 446, IP 71, BS 188, USP <911>|
We offer typical values which are based on the values in brochures and standards but are not related to specific instruments.