Patent ID: 8822927

Claim:
A device to measure the characteristics of droplets within a stream of liquid droplets used in spraying comprising: a light source supplying light across the stream of droplets to be analysed; a detector to detect, from light passing straight across the stream of droplets, the change in the level of light caused by a droplet passing through the light produced by the light source, the droplet casting a shadow on the detector, thus generating a signal according to the change in light incident thereon; and a processor to analyse the characteristics of the droplets in the stream based on the signal produced by the detector; a panel disposed between the droplet stream and the detector and defining a horizontally disposed slit; a mask disposed between the droplet stream and the detector and defining a vertically disposed slit; wherein the light passes through the slit defined by the panel and through the slit defined by the mask, so that the change in level of light caused by the droplet shadow and detected by the detector is proportional to the diameter of the droplet.