Rotationsviskosimetrar

Rotationsviskosimetrar, also known as rotational viscometers, are laboratory instruments used to measure the viscosity of fluids by applying a controlled rotational force to a probe immersed in the sample. These devices operate on the principle of rotational shear, where the torque required to rotate a spindle at a constant speed within a fluid is directly related to the fluid’s viscosity. Rotationsviskosimetrar are widely employed in industries such as pharmaceuticals, food processing, cosmetics, and petrochemicals due to their precision and adaptability to various fluid types, including non-Newtonian substances like paints, adhesives, and biological fluids.

The basic design of a rotationsviskosimetrar consists of a spindle submerged in the test fluid, connected to a motor that applies rotational motion. Sensors detect the torque exerted by the fluid on the spindle, which is then converted into viscosity measurements using calibrated equations. Some advanced models incorporate temperature control to ensure accurate readings across different thermal conditions. These instruments can be configured for different spindle shapes and rotational speeds to accommodate a broad range of viscosity values, from highly viscous materials like molten plastics to low-viscosity liquids such as water.

Rotationsviskosimetrar offer several advantages, including high repeatability, ease of use, and the ability to measure both shear-thinning and shear-thickening fluids. However, they require careful calibration and proper sample preparation to avoid errors caused by factors such as air bubbles or non-uniform fluid distribution. Compared to capillary viscometers or falling-ball viscometers, rotational viscometers provide more versatile and dynamic measurements, making them a preferred choice for quality control and research applications where viscosity plays a critical role in product performance.