Construction of a microbubble generation and measurement unit for use in flotation systems

[Display omitted] •Microbubble generation and measurement unit was constructed with Arduino UNO R3®.•The small air flow measurement system showed uniformity of measurement.•A R2 of 98% for the calibration curve between airflow and pressure variation was found.•The microbubble images were captured with quality for future measurements. Flotation with microbubbles is one of the most viable methods for separating oil from water. Microbubbles are formed by the injection of a small air flow through a pressurized liquid flow. In the present study, a microbubble generation and measurement unit (MBGMU) was constructed to measure mean microbubble size through the liquid flow and airflow of the system. The liquid flow rate was measured by a Hall effect-type sensor, whereas it was necessary to construct a sensor for bubbles immersed in glycerin for the determination of the airflow rate. This sensor was used to determine the minimum and maximum airflow limits, and the airflow measurements were compared with pressure gauge readings to establish a calibration curve. The Arduino UNO R3® board was the microcontroller of the MBGMU for the determination of the liquid flow rate. A coupled system involving a GoPro® Hero 6 camera and microscope lenses was assembled to capture images of the microbubbles. The airflow rate ranged from 0.001 to 10,000l/h, and a high linear regression coefficient was found (98%) for the calibration between airflow and the variation in pressure. Images of microbubbles in motion were captured for future analyses. This innovative device is a promising system to be applied in industrial processes for the control of microbubbles produced in flotation systems.