主要性能和长处
Rigid frame design
The RH2000 series mechanics are contained within a rigid one-piece housing which gives the cantilever design extreme strength and stiffness. This is an important consideration in transient tests such as PVT, which rely upon compliance free measurement for accurate volume determination.
Swivel head design
A unique, safety interlock protected, swivel design means that the actuated part of the rheometer (流变仪) can be moved to one side giving complete ease of access for cleaning and sample loading.
Bi-Modal speed control
Malvern has developed a bespoke Bi-Modal digital speed control technology to control the latest generation of capillary rheometers (毛细管流变仪). The technology uses different speed control algorithms suited to high and low speed operation in order to optimize performance. This gives the rheometer (流变仪) an impressive dynamic range in speed control. In practice, the lower limit is determined only by long experimental times at low shear rates (切割率) but a dynamic range in speed of in excess of 200,000:1 is available if required. This greatly enhances the system's flexibility and means that a wider range of shear rates (切割率) can be covered using a particular die.
Rosand Twin Bore Principle (RH2200 model)
Malvern was the first manufacturer to introduce the twin bore measurement principle in a commercially available rheometer (流变仪) unit. Simultaneous measurements can therefore be made on both long and short dies to determine the inlet pressure drop at the die, and therefore absolute viscosity, using the Bagley method. More commonly, Rosand 'zero length' dies are used to directly measure the inlet pressure drop and measure the extensional viscosity using the Cogswell (钝齿膨胀) method. The twin bore technique gives obvious experimental advantages including improved throughput since both experiments are preheated simultaneously. Alternatively, the software can be configured to run a two material test, thus measuring the apparent viscosity of two different materials simultaneously. |
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