New Venturi Flowmeter Based on Differential Pressure Method

A new Venturi flowmeter was designed and fabricated to realize the pesticide flow rate detection in the process of pesticide automation mixing during agricultural spraying. A problem of mini or micro-flow detection of pesticide was solved. This flowmeter is mainly composed of a special Venturitube, a differential pressure (DP) sensor, an instrumentation amplifier and a microcontroller STC12C5410AD. The differential pressure between the inlet channel and the throat channel of Venturitube is detected by a DP sensor and converted into voltage which is amplified by an instrumentation amplifier, and then the voltage is collected and processed by the microcontroller when liquid flows through the Venturitube. The calibration experiments of the DP Venturi flowmeter in a certain dimension were carried out by using water as a working fluid at the temperature of 15 degrees C. The experimental results show that the proposed DP Venturi flowmeter is feasible for sprayer with errors less than +/- 1.5%. This DP Venturi flowmeter has the advantage of simple structure so that it is a good method for sprayer pesticide flow rate measurement and other aeras.