Rotating Cylinder Viscometer

A rotating cylinder viscometer is described which depends for its operation upon measuring the frequency of a periodic flow. Compared with viscometers in common use, the results of this instrument are influenced to a smaller extent by end effects, difficulties of adjustment, or the requirement for high precision parts of special materials. It features ease of construction and maintenance, the adaptability to continuous sampling and monitoring, and a precision of about 0.3% in the measurement of the kinematic viscosity. The sensitivity of the apparatus to various aberrations is illustrated. Design considerations and attainable performance standards are discussed.