Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Experimental estimation of the moisture content of cotton bales through required hydraulic force
Submission Author:
André Araújo Fernandes , SP
Co-Authors:
André Araújo Fernandes, Gabriel Alberto Bermudez Arias, André Vecchione, Thiago Boaventura
Presenter: André Vecchione
doi://10.26678/ABCM.COBEM2023.COB2023-1452
Abstract
Measurement and control of the moisture content (MC) of cotton bales is a primary issue in cotton ginning. Low MC reduces profitability, with higher machine wear and lower fiber quality. If the MC is too high, it is harder to clean and separate the lint from the seed. High MC cotton bales also degrade in storage, changing color and, therefore, losing value. The dielectric properties of cotton are greatly affected by water, and most commercial MC sensors are based on this effect. Microwave sensors (non-contact measuring devices) are usually installed after the baling press and encompass most of the bale volume, but are expensive. Capacitance-based sensors are a cheaper alternative. They are hand-held devices that use a probe to estimate the MC of a small region in the bale. Another way to measure the MC is through the mechanical effort required to press the cotton lint into a bale. There is a direct relationship between the force exerted by the hydraulic press and the overall MC of the bale, for bales of the same mass. This article investigates this relationship by measuring the maximum hydraulic pressure and then measuring the MC by oven drying. To generate the required data, an automated hydraulic press was used to manufacture reduced-scale cotton bales following commercial standards. The project and automation of this hydraulic press are shown. Pressure transducers were used to measure hydraulic pressure throughout the process. The force exerted can be determined by relating the area of the hydraulic cylinder and the diameter of the rod with the pressure in the line. After being weighed, the cotton bale is untied and placed in baskets inside a drying oven. The baskets hang from a structure fixed to a load cell outside the oven, allowing weight measurements while drying. This experiment follows the ASTM D2495 standard. The results showed a linear relationship between the logarithm of the force and the MC of the bale. Finally, a comparison between the measurements of a commercial capacitive sensor, a microwave sensor, and the developed method showed satisfactory agreement. The overall MC of the bale can then be estimated without additional sensors.
Keywords
moisture content, Cotton bale, PLC, Hyrdraulic Press
