BYK-Gardner 0643 Glass Bubble Viscosity Tube, Certified W Standard, 9mL Capacity

The BYK-Gardner 0643 replacement bubble viscometer standard tube has a viscosity of approximately 1,073 centistokes (cSt), and is suitable for testing fluids such as resins and varnishes. The 9mL capacity sealed bubble tube standard is lettered W and has a bubble test time of approximately 11.5 seconds. Sample fluid viscosity is determined by comparing bubble rise time to those of bubble tube standards and choosing the closest match. The sealed standard tube has a 15-year shelf life and can be National Institute of Standards and Technology (NIST) recertified. This bubble viscometer standard tube is ASTM International certified and meets the ASTM International D1545 standard for testing viscosity.

A viscometer, also called a viscosimeter, is an instrument used to measure the friction caused by the relative motion of a Newtonian fluid and a known surface, and is usually expressed in units of poise (P), centipoise (cP), pascal seconds (Pa s), and millipascal seconds (mPa s). Viscometers have several forms, including but not limited to falling ball, rotational, vibrating, capillary, funnel, and bubble. A falling ball viscometer measures the time it takes for a ball of known diameter and density to fall through fluid in a cylinder of known diameter. A rotational viscometer measures the force required to stir a fluid. A vibrating viscometer measures the power input necessary to keep the oscillator vibrating at constant amplitude while immersed in a fluid. A capillary viscometer has a narrow-bore vertical section with two printed marks that measure time required for a known volume of fluid to fall a known distance. A funnel viscometer, such as a Ford, Zahn, or Shell cup, measures the time it takes a known volume of fluid to flow from the base of a cone through a short tube. A bubble viscometer measures the time required for an air bubble to rise through a fluid. Viscosity measurements are used in laboratories, research and development, process control, and plant quality control applications. Some viscometers are manufactured to meet industry or governmental standards, including Ingress Protection (IP), National Institute of Standards and Technology (NIST), International Standards Organization (ISO), and ASTM International (formerly American Society for Testing and Materials)

BYK-Gardner manufactures additives that enhance material properties and testing equipment for commercial and industrial applications. The company, founded in 1873 and headquartered in Geretsried, Germany, is a division of Altana Group.