| 摘要 |
<p>Method of controlling the evaporation of the droplet cloud resulting from nebulization of a liquid expelled from a liquid droplet spray device, wherein said liquid droplet spray device comprises a reservoir for containing the liquid, a perforate membrane plate, fluid interface means for feeding the liquid from the reservoir to the membrane plate, ultrasound generating means for acting on the supplied liquid to cause it to be expelled as a spray of droplets through orifices of said membrane plate and electronic control means for controlling the activation of the ultrasound generating means. The method comprises the steps of:
providing the liquid droplet spray device,
supplying the liquid to a space below the perforated membrane plate,
providing a pulsed driving signal having a period T for activating the ultrasound generating means,
activating the ultrasound generating means for a period of time T on so as to cause the spray of droplets to be expelled at a maximum spray cloud height, T on consisting of T ona and T onb ,
de-activating the ultrasound generating means for a period of time T off , where T off ‰¥ T on + T evap ,
wherein T evap is the time that is required for the sprayed cloud of a given liquid produced during T on to fully evaporate,
wherein T ona is the time required to ultrasonically energise the liquid, T onb is the time to spray the liquid, and T ona lasts from less than tens of milliseconds to several seconds,
whereby the amount of unevaporated liquid that falls back on a surface surrounding said liquid droplet spray device is minimised.</p> |
