Experimental study on improving deposition rate using PWM-based intermittent spray from enlarged nozzle

In order to obtain appropriate small spray droplet size spectra and increase spray droplet velocity, so as to improve pesticide spray deposition rate, a method to improve spray deposition rate using PWM-based (pulse width modulation, PWM) intermittent variable spray technology was discussed. Through four groups of comparative tests, the effects of three kinds of flow-rate control methods on spray droplet sizes and velocity were compared. The three flow-rate control methods are: 1)spray flow-rate control by changing pressure, 2)spray flow-rate control by PWM-based intermittent variable spray, and 3)spray flow-rate control by combining PWM-based intermittent variable spray, variety of nozzle size, and change of pressure. The study results show that not only can the flow-rate be controlled, but also suitable smaller droplet diameter spectra can be obtained and spray droplet velocity can be increased through adjusting spray duty cycle, spray pressure, and nozzle size using the method of PWM-based intermittent spray from enlarged nozzles operated at increased liquid pressure. Therefore, spray deposition rate could be improved.