Aerosol Spray Cans :: essays research papers fc

Aerosol dot CansSpray cans produce an aerosol, the technical term for a very fine atomizer.They do this by means of a pressurized propulsive, which is a runniness that boilsat universal temperatures. Inside the can, a form of petroleous pressure increased,and eventually it becomes so high that boiling stops. when the nozzle is pressed,the burn out pressure forces the overlap up the tube in the can and out of the nozzlein a spray or foam. The dynamic may emerge as head but, now under lesspressure, it immediately evaporates.First patented in the US in 1941, aerosol spray cans have been used asconvenient packages for an ever increasing range of products including paints,insecticides, and shaving cream to differentiate a few. The can is filled with theproduct to be sprayed and the propellant, a mat gas such as butane orFreon. The gas is partly liquefied by the pressure in the can, but there is alayer of free gas above the liquid. As the can empties liquefied gas vaporizest o fill the space.The valve is normal held shut by the pressure in the can, and by thecoil spring directly below the valve tooth root. When the push button is pressed, itforces the valve stem down in its housing, uncovering a sharp a small hole whichleads up through the stem to the nozzle in the button. This allows the productto be forced up the leaning tube by the gas pressure in the can. The nozzle isshaped to give a spray or a continuous menstruation.To produce a fine mist, a propellant is used which mixes with theproduct. The two leave the nozzle together and the propellant evaporates a soonas it reaches the air, breaking the product in to comminuted droplets. The sametechnique used with a more viscous liquid and a wider nozzle results in a foam.For a continuous stream of liquid or more viscous material, a nonmixingpropellant is used, and the dip tube reaches into the product.The widespread use of aerosol cans using Freon as the propellant ledscientists to believe by the lat e 1970s that the ozone layer in the upperatmosphere, which filters out harmful Ultraviolet radiation from the sun, couldbe finished by the large quantities of fluorocarbons in the gas being releaseinto the air. federal official controls were introduced to ban the use of Freon, andother propellants are now employed, notably butane which, unless is dangerouslyflammable.Among young people in United States, conventional drug or alcohol abusehas given away-for an increasing number of teen-agers-to a practice called