New developments from Bohlin Instruments

Citation

(2002), "New developments from Bohlin Instruments", Industrial Lubrication and Tribology, Vol. 54 No. 1. https://doi.org/10.1108/ilt.2002.01854aad.003

New developments from Bohlin Instruments

Keyword: Bohlin

Bohlin Instruments has developed a direct strain control oscillation feature for its digital DSP based rheometer range, which includes the new C-VOR. The new oscillation mode enables oscillation tests to be performed directly at a pre set strain amplitude. This feature can be especially useful in a number of practical applications. For example, it avoids the time consuming need to iteratively adjust the stress amplitude on successive oscillation cycles in order to achieve a target strain. For curing or gelling systems where rapid changes in modulus can lead to large variations in strain if a stress controlled test is performed, it is now possible to directly regulate the strain amplitude. This not only generates data points more rapidly but also has the additional benefit of closely controlling the sample's strain history. In addition to the strain controlled oscillation testing, Bohlin has also introduced partial wave analysis for the oscillation mode. This feature dispenses with the need to sample an entire waveform during an oscillation test. Instead, the user can select just part of a wave to be analysed with, typically, just a minimal loss of precision in modulus or phase angle resolution. Besides obvious time saving advantages for general work, the partial wave mode is able to give extremely fine resolution along the time domain during material transitions such as curing where, for example, several points per second can be acquired at 1Hz oscillation frequency.

Bohlin Instruments has also introduced the CP180 Coaxial Cylinder Peltier. For fluids applications, CP180, a rapid, Peltier based, temperature control module with coaxial cylinders (cup and bob geometries). The CP180 is designed for use with the Bohlin CVO and C-VOR rheometers. For the vast majority of fluid applications, the CP180 dispenses with the need for a separate fluids circulator for use with cylinder geometries. The new system differs from conventional units in its ability to effect very rapid changes in the test temperature. Ramping rates of up to 30^oC per minute can be achieved with the new unit with a maximum temperature of 180^oC. This makes the CP180 especially suitable for applications such as starch and other foodstuffs where very rapid changes in temperature are required in order to simulate processing conditions. Several removable sample cup sizes are available for flexibility and ease of cleaning. The CP180 is available as a simple retrofit to existing CVO and C-VOR users.

For more information contact Lynda Watson at Bohlin Instruments Ltd, The Corinium Centre, Cirencester, Gloucester, GL7 1YJ UK. Tel: +44 1285 644407; Fax: +44 1285 644314; E-mail: lw@bohlin.com; Web site: www.bohlin.com