The mining operations of the Middle Ages led to development of the suction (piston) pump, many types of which are described by Georgius Agricola in De re metallica (1556). A suction pump works by atmospheric pressure; when the piston is raised, creating a partial vacuum, atmospheric pressure outside forces water into the cylinder, whence it is permitted to escape by an outlet valve. Atmospheric pressure alone can force water to a maximum height of about 34 feet (10 metres), so the force pump was developed to drain deeper mines. In the force pump the downward stroke of the piston forces water out through a side valve to a height that depends simply on the force applied to the piston.
As for the sprayer, there are also many kinds like Plastic Hand Trigger Sprayer, Plastic Fine Mist Sprayer, Perfume Mini Sprayer and Perfume Credit Card Sprayer. cosmetic industry developed prediction models for the best estimate of inhalation exposure combining data from computer simulation programs available in the market, individual real measured data and last but not least the experience from the market. Such attempt is driven by the toxicological profile of individual used ingredients. The focus of this review is on the determination of inhalation exposure, and the derivation of safe exposure levels for cosmetic spray products. Many of the methods employed to ensure product safety of cosmetic sprays in accordance with the general requirements of the EC Cosmetics Directive are based on industry experience which are not necessarily consistent across companies.
