Reduction in environmental pesticide contamination

Oxford Lasers VisiSizer systems are being used to characterise the size spectrum of sprays produced by new nozzle designs for pesticide sprays, to reduce the spray drift and consequent pollution

The problem of pesticides drifting from the area in which they are required leads to pollution and inefficient use of pesticides.

In the 1980s and 90s institutions in Europe and the Spray Drift Task Force in the USA were established to look at ways of minimising this worldwide problem.

After extensive practical trials it has been concluded that droplet size is one of the most important factors affecting 'spray drift'.

Oxford Lasers VisiSizer systems are now being used to characterise the size spectrum of sprays produced by new nozzle designs for pesticide sprays.

Sizing software is combined with a pulsed laser that eliminates 'motion blur' and visualises the effect of new 'air-inclusion' nozzles that have been developed to combat the 'spray drift' problem.

Droplets produced by one of these devices can contain bubbles, as a result, making sizing difficult for alternative techniques.

The VisiSizer system employs a back illumination technique and droplets appear as black on a white background.

Particle can be sized at the rate of 7,680 drops per second in real time.

The droplets can be of any shape or size and can even be non-spherical.

VisiSizer is not deceived by out-of-focus droplet images.

By measuring the sharpness of the image edges, VisiSizer automatically corrects for this effect.

Oxford Lasers VisiSizer is not only able to see droplets clearly but has produced unique images of droplets that themselves contain air bubbles.

To see this remarkable phenomenon go to the website and look at the Drop, Bubble and Particle Sizing page.

While drop size and velocity distribution information is vital in developing pesticide spray nozzles, it is the interaction of droplets with plants that determines the effectiveness of the delivery system and whether the droplets stay on the plant/leaf or bounce off to form a 'drift' problem.

A sequence of images captured by Oxford Lasers VisiSizer can be viewed as a movie.

This then shows exactly how many droplets are bouncing off the plant/leaf on impact and how many are adhering to the surface.

The Oxford Lasers range of VisiSizer systems can also be used to measure the following.

* bubble columns.

* deodorant sprays.

* hair sprays.

* fire suppression sprays.

* fuel injector sprays.

* airborne powders.

* paint sprays.

* inkjet printer sprays.

* medical device sprays and many others.

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