Projeto de uma bancada experimental de placas de orifício para medição do fornecimento de ar a sistemas de leito fluidizado de laboratório

Abstract

Orifice plates are devices used to measure the flow rate of fluids transported in a pipeline. They are widely used for their low cost of construction and maintenance, as well as for their good accuracy and integration with data acquisition systems for automation of processes where it is necessary to regulate the supply of fluids. The mass flow rate determined by the instrument is proportional to the pressure drop caused in the stream during its passage through a hole located in the plate. With the purpose of assist experimental studies in laboratory fluidized systems, this work designs an experimental bench of orifice plates that provides a wide range of operation (1 kg/h to 780 kg/h), composed of two sets of meters connected in parallel and that allow, each one of them, the accommodation of up to five plates with different hole sizes. Operational verifications were carried out in order to determine the Best performance ranges for each proposed orifice plate geometry. For this, the criteria were the air pressure supplied to the equipment, the characteristics of the instruments available for reading the pressure data measured in the orifice plate and the energy expenditure required for its operation. Results showed that, for the supply of air with an absolute pressure of 2 and 3 bar, the set of plates in the 1inch pipe can provide a maximum mass flow rate of 125 kg/h and 199 kg/h, respectively; while the set installed in the 2inch pipe, this maximum mass flow rate rises to 490 kg/h and 781 kg/h, respectively.