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High-stability viscometer baths 

for kinematic viscosity testing

Our viscometer baths are engineered for exceptional temperature control, essential for accurate kinematic viscosity measurements. Designed to meet the stringent demands of ASTM D445, ISO 3104, and IP 71 protocols, these constant temperature baths maintain temperature stability & uniformity within ±0.01 °C across the entire volume. 

Each model accommodates a range of capillary viscometers and comes equipped with intuitive digital controllers, safety features, and optional automation interfaces. Suitable for petrochemical labs, polymer testing, and precision calibration environments.

Ultra-stable constant temperature baths for viscosity testing

TCB-7 Viscometer Bath | PSL Rheotek

Temperature control you can trust


PSL Rheotek viscometer baths are engineered for laboratories that need high-precision thermal stability in accordance with ASTM D445, ISO 3104, and IP 71 viscosity methods. Each bath is designed for compatibility with glass capillary viscometers and delivers exceptional uniformity of temperature across all positions.

Lab-ready precision


  •  ±0.01 °C temperature stability Ensure compliance and reproducibility in kinematic viscosity tests. Each bath features tight temperature control over long runtimes.
  •  Compatible with all viscometer types Supports Ubbelohde, Cannon-Fenske, and reverse flow viscometers. Interchangeable racks and clamps provide universal fit.
  •  Digital control, safety, and automation Baths are fitted with digital PID temperature control, overheat protection, and optional interfaces for integration with automated testing systems.
  •  Available in multiple sizes From compact 2-place units to high-throughput 7-place models, there's a size for every lab capacity and workflow.
Why is a constant temperature bath essential for viscosity testing?

Viscosity is highly temperature-dependent. A ±0.01 °C stability ensures test repeatability and compliance with methods like ASTM D445, ISO 3104, and IP 71. Baths with poor temperature uniformity lead to inaccurate, non-reproducible results.

How often should the bath temperature be validated?

The general recommendation is to validate the bath temperature at least once every 12 months as part of the standard Quality Assurance routine of the laboratory. Some laboratories may have shorter validation intervals.

What size viscometer baths are available?

Our range includes compact 2-place models to large 7-place baths. Custom configurations are also available for high-throughput labs or special test tubes.

What bath medium do you recommend?

At measurement temperatures between 20 and 50 degrees C, our recommendation is to use demineralised water. At temperatures of 60 degrees C and above, we recommend to use silicone oil or a light mineral oil.