Diseño de un dispositivo detector de obturaciones en aplicaciones de fertilizantes líquidos

The high cost of the liquid fertilizer application equipment, unaffordable for the majority of the farmers, forces them to derive the fertilizer contributions to the utilities. Due to the big demand of these applications, the utilities are forced to make applications during the day and at night. The fact of doing them at night hinders the tractor the visibility of the back side of the equipment, which makes difficult to test the quality of the application. For this reason when an obstruction happens in any of the equipment nozzles or in any of its lines and the driver does not realize, the application is no longer correct which leads to serious agronomic problems for the farmer and economic prejudices for the utilities. This project tries to find a system able to detect the obstructions in the liquid fertilizer application equipment. For this, four different sensors were analysed and tested based on optic, photoelectric, ultrasound and pressure sensors. The designed system had to be able to detect the nozzle obstruction and send the information to a console located in the tractor cab, allowing the driver the control of the application quality during the whole time. The results obtained after the testing gave as a result the design of a system composed by an ultrasound sensor and a led device located in the tractor cab. The project also includes the economic evaluation of the designed prototype. The optic sensors in any of the cases detected a change between presence and absence of fluid, whereas the pressure sensor detected the changes in some of the cases and the ultrasound sensor always detected the difference. L'elevat cost dels equips d'aplicació de fertilitzants líquids, inassolible per la gran majoria d'agricultors, obliga a derivar les aportacions de fertilitzant a les empreses de serveis. Davant la gran demanda d'aquestes aplicacions, les empreses de serveis es veuen obligades a realitzar aplicacions durant el dia y durant la nit. El fet de realitzar-les per les nits dificulta molt al tractorista la visibilitat de la part posterior de l'equip, el que dificulta la comprovació de la qualitat de l'aplicació. Per aquest motiu quan es produeix una obturació a qualsevol dels broquets de l'equip o a alguna de les seves conduccions i el tractorista no s'adverteix, la aplicació deixa de ser correcta el que suposa greus problemes agronòmics per l'agricultor i greus perjudicis per a les empreses de serveis. Amb aquest treball es pretén trobar un sistema capaç