Método de Cuckow para la calibración de aerómetros : diseño y puesta a punto del equipo

Abstract

The method used in Laboratorio Tecnológico del Uruguay (LATU) for hydrometers calibration is the “Cuckow method for hydrometers calibration using water added with a surfactant as a standard”. A surfactant is used to decrease the surface tension of distilated water used as a standar and is verified that the density variation of distilated water produced by the surfactant adds a small contribution to the uncertainty of the method and can be contemplated within the accepted uncertainty for the density of distilated water. A strategy to reduce the uncertainty calibration of the method was planned; to perform it a container with a system of thermostatization with recirculating water per jacket to provide thermal stabilization to the system was designed, shaking to improve the thermostatization and avoid gradients of density associated with inhomogeneities in the temperature. Improvements were made in the adjustment system of reading and shape of the meniscus. The improved method was validated again and it was demonstrated that improvements help to reduce the uncertainties of calibration, giving the possibility to apply it for calibration of precision hydrometers. In this article considerations in designing and working conditions adjustments of the improved equipment are detailed, mainly in the container and its jacket for recirculating water of thermostatization. This raises its construction with tubes of glass available on the market and lowering the costs.