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BS U-Tube viscometers for opaque liquids
+ infoDynamic viscosity measurement for laboratory and industrial applications
Dynamic viscosity measurement is essential for evaluating how liquids and semi-solid materials resist flow under applied force. Accurate viscosity data supports product development, quality control and process optimisation across a wide range of industries.
Fungilab provides complete dynamic viscosity measurement solutions based on precision rotational viscometers, temperature control systems and specialized accessories designed to deliver reliable, repeatable and traceable laboratory results.
Whether measuring low-viscosity liquids or highly viscous materials, Fungilab offers instruments adapted to routine laboratory testing as well as demanding research applications.
Our products
Viscolead Series
Viscolead ONE
Viscolead ADV
Accessories
LABORATORY DIVISION
Dynamic viscosity
Viscosity is part of the science of Rheology which quantifies the resistance materials give to changing shape.
Proper interpretation of viscosity data can reduce the rate of rejects while keeping production and formulation development costs to a minimum. Consistent product quality is ensured through proper viscosity measurements, either alone or in conjunction with compatible tests.
Dynamic viscosity testing can help with:
- Material characterization or “finger-printing”
- Standard testing methods to check for differences between batches
- Indirect way of measuring quality
- Product formulation
- Quality control
- Process control
- Design, optimization and operation of process equipment
Material characterization or “finger-printing”
Standard testing methods to check for differences between batches
Indirect way of measuring quality
Product formulation
Quality control
Process control
Design, optimization and operation of process equipment
Viscosity types
Dynamic viscosity
Centipoise (mPa*s)
Kinematic viscosity
Centistokes (mm2/sec)
Apparent viscosity
Centipoise (mPa*s)
Newton’s Law
According to Newton’s law, the viscosity of a fluid is constant. As shear rate changes, shear stress changes in proportion such that viscosity is constant. Common fluids that exhibit such behavior are:
Unfortunately for us, not all fluids follow Newton’s law. In fact, most fluids do not. For this reason, fluids are classified into two categories:
Rotational Viscometer
The viscosity is calculated from the measured torque and rotational speed, as well as the dimensions of the measuring geometry.
A fluid’s resistance to flow is measured by the torque it exerts on the rotating shaft of the viscometer.
Absolute viscosity: the measuring geometry fulfills certain requirements (which is the case of coaxial spindles).
Relative viscosity: the dimensions of the measuring geometry are not well defined.
Advantage
Flexibility in:
- Viscosity Range
- Temperature range
- Shear rate range
Application
For Newtonian and non-Newtonian substances and temperatures different from room temperature.
Reverse-flow capillary viscometers for opaque samples
The BS/IP/RF U-Tube reverse-flow viscometer is specifically designed for measuring the kinematic viscosity of opaque Newtonian liquids. Its measuring configuration makes it possible to determine flow time without relying on the same visual conditions required by conventional capillary viscometers for transparent samples.
This makes the instrument suitable for dark petroleum products, lubricants, oils, chemical products and other samples where colour or opacity can make standard viscosity measurement difficult.
Standards for BS U-Tube viscosity testing
Fungilab BS U-Tube viscometers for opaque liquids are manufactured according to recognised viscosity testing procedures, including:
- ASTM D445
- ASTM D446
- ISO 3104
- ISO 3105
- UNE 400313
Main characteristics
- Reverse-flow configuration for opaque liquids.
- Borosilicate glass construction.
- Permanent and non-alterable timing marks.
- Measurement precision of approximately ±0.3%.
- Calibration certificate with constant values at 40°C and 100°C.
- Suitable for laboratory and industrial quality control.
Calibration and measurement traceability
Each capillary viscometer is supplied with an individual calibration certificate issued under the accreditation requirements of a National Metrological Register. This documentation supports measurement traceability, laboratory capability and uncertainty evaluation according to recognised international standards.
Accurate kinematic viscosity measurement also requires stable sample temperature. The Fungilab Thermocap precision bath provides controlled conditions for measurements performed with glass capillary viscometers.
BS U-Tube viscometers for transparent and opaque liquids
Fungilab offers BS U-Tube capillary viscometers for both transparent and opaque samples. Standard BS U-Tube models are intended for transparent Newtonian liquids, while BS/IP/RF reverse-flow models are designed for opaque liquids.
Other available solutions include Cannon-Fenske viscometers and Ubbelohde viscometers for different kinematic viscosity measurement methods and sample requirements.
Applications for opaque liquid viscosity measurement
BS U-Tube reverse-flow viscometers are suitable for viscosity testing in sectors such as petroleum, lubricants, oils and chemicals. They can be used for routine quality control, batch comparison, product verification and laboratory research.
Fungilab can help select the appropriate capillary size and measuring range according to the expected viscosity, sample characteristics, operating temperature and applicable testing standard.
Frequently asked questions about the Viscolead ADV
What is a BS U-Tube viscometer for opaque liquids?
It is a reverse-flow glass capillary viscometer designed to measure the kinematic viscosity of dark, coloured or opaque Newtonian liquids.
Why is a reverse-flow viscometer used for opaque samples?
The reverse-flow configuration allows reliable flow-time measurement when the sample is too dark or opaque for conventional observation methods used with transparent-liquid capillary viscometers.
Which standards apply to BS U-Tube viscometers for opaque liquids?
Fungilab BS/IP/RF U-Tube viscometers are manufactured according to ASTM D445, ASTM D446, ISO 3104, ISO 3105 and UNE 400313.
What measurement precision do these viscometers provide?
The BS/IP/RF U-Tube reverse-flow viscometers for opaque liquids provide a measurement precision of approximately ±0.3%.
Are BS U-Tube viscometers supplied with a calibration certificate?
Yes. Each viscometer is supplied with an individual calibration certificate that includes constant values at 40°C and 100°C and provides traceability to recognised international standards.
Which samples can be measured with a BS U-Tube reverse-flow viscometer?
Typical samples include opaque petroleum products, lubricants, oils, chemicals and other dark Newtonian liquids requiring accurate kinematic viscosity measurement.
Is temperature control necessary during capillary viscosity testing?
Yes. Kinematic viscosity is strongly affected by temperature, so measurements should be performed under stable and controlled thermal conditions using a suitable precision bath.
What is the difference between BS U-Tube models for transparent and opaque liquids?
Standard BS U-Tube models are designed for transparent Newtonian liquids, while BS/IP/RF reverse-flow models are specifically intended for opaque liquids.
