An aerosol spray is a kind of expenditure system that creates a liquid aerosol particles. These are used with cans or bottles containing the charge and propellant under pressure. When the container valve is opened, the payload is forced out of the small opening and appears as an aerosol or fog. As the propellant expands to dissipate the charge, only a few propellants evaporate inside the tin to maintain a constant pressure. Outside the cans, the propellant droplets evaporate rapidly, leaving a charge suspended as a very fine particle or droplet.
Video Aerosol spray
History
The concept of aerosol may go as far as 1790. The first aerosol spraying can be patented granted in Oslo in 1927 to Erik Rotheim, a Norwegian chemical engineer, and a US patent granted for discovery in 1931. The patent was sold to a US company worth 100,000 Norwegian kroner. The Norwegian Postal Service, Posten Norge, celebrated this discovery by issuing a stamp in 1998.
In 1939, the American Julian S. Kahn received a patent for a single-use spray can, but the product was largely undeveloped. Kahn's idea is to mix cream and propellant from two sources to make whipped cream at home - not a true aerosol in that sense. In addition, in 1949, he denied his first four claims, which form the basis of his patent claims. New in 1941 aerosol spray was first used by Americans, Lyle Goodhue and William Sullivan, who were considered inventors of modern spray cans. Their refillable spray design can be nicknamed "bug bomb", is the ancestor of many popular commercial spray products. Pressurized with liquefied gas, which gives it a small, portable, propellant quality can allow soldiers to survive against malaria-carrying mosquitoes by spraying tents and planes in the Pacific during World War II. Goodhue and Sullivan received the first Erik Rotheim Gold Medal from the Federation of Aerosol European Associations on August 28, 1970, in Oslo, Norway in recognition of their initial patents and subsequent pioneering work with aerosols. In 1948, three companies were licensed by the United States government to produce aerosols. Two of the three companies, Chase Products Company and Claire Manufacturing, are still producing aerosols to this day. "Crimp-on valve", used to control sprays in low-pressure aerosols was developed in 1949 by Bronx machine shop owner Robert H. Abplanalp.
In 1974, Drs. Frank Sherwood Rowland and Mario J. Molina propose that chlorofluorocarbons, used as propellants in aerosol sprays, contribute to the depletion of the Earth's ozone layer. In response to this theory, the US Congress passed the amendment of the Clean Air Act in 1977 which authorized the Environmental Protection Agency to regulate the presence of CFCs in the atmosphere. The United Nations Environment Program called for ozone layer research in the same year, and, in 1981, adopted a global framework convention on ozone layer protection. In 1985, Joe Farman, Brian G. Gardiner, and Jon Shanklin published the first scientific paper detailing the hole in the ozone layer. In the same year, the Vienna Convention was signed in response to the UN authorization. Two years later, the Montreal Protocol, which governs the production of CFCs, is officially signed. This came into force in 1989. The US officially abolished the CFC in 1995.
Maps Aerosol spray
Propellant aerosols
If the aerosol cans are only filled with compressed gases, it may have to be at a dangerous high pressure and require the design of a special pressure vessel (as in a gas cylinder), or the amount of load in the can is small, and quickly exhausted. Usually the gas is a liquid vapor with a boiling point slightly lower than room temperature. This means that in pressurized cans, the vapor can be in equilibrium with its bulk liquid at a higher pressure than atmospheric pressure (and capable of driving out the load), but not very high. When the gas comes out, it is immediately replaced with evaporative fluid. Since the propellant exists in liquid form in the can, it must be mixed with the load or dissolved in the payload. In gas dusters and frozen sprays, the propellant itself acts as a charge. The propellant in the duster may not be "compressed air" as it is sometimes assumed, but it is usually a haloalkane.
Chlorofluorocarbons (CFCs) used to be used as propellants, but since the Montreal Protocol came into force in 1989, they have been replaced in almost every country because of the negative effects of CFCs on the Earth's ozone layer. The most common CFC substitute is a mixture of volatile hydrocarbons, usually propane, n-butane and isobutane. Dimethyl ether (DME) and methyl ethyl ether are also used. All of these have flaws because they are flammable. Nitrous oxide and carbon dioxide are also used as propellants to deliver foodstuffs (eg, whipped cream and cooking spray). Aerosol drugs such as asthma inhalers use hydrofluoroalkanes (HFA): either HFA 134a (1,1,1,2, -tetrafluoroethane) or HFA 227 (1,1,1,2,3,3,3-heptafluoropropane) or a combination of both. Manual pump sprays can be used as an alternative to stored propellants.
Packaging
Modern aerosol spray products have three main parts: cans, valves and actuators or buttons. The most common lacquered cans are tinplate (steel with lead layers) and can be made of two or three adhesive metal parts. Aluminum Cans are also common and are generally used for more expensive products. The valve is glued to the edge of the can, and the component design is important in determining the spray rate. The actuator is pressed by the user to open the valve; the spring closes the valve again when it is released. The shape and size of the nozzles in the actuator controls the spread of aerosol sprays.
Alternative non-aerosol packaging
By definition, aerosol sprays release their propellants when used. Some non-aerosol alternatives include the following which are shown below.
Packaging using a piston barrier system by CCL Industries or EarthSafe by Crown Holdings is often selected for highly viscous products such as post-foam hair gel, thick cream and lotion, food dispersion and industrial products and sealants. The main benefit of this system is that it removes gas permeation and guarantees the separation of the product from the propellant, maintaining the purity and integrity of the formulation over the life of its consumers. The piston barrier system also provides consistent flow rates with minimal product retention.
Another type of expenditure system is a bag-in-can (BOV, bag-on-valve technology) system in which the product is separated from a pressurized agent with a sealed laminated pouch enclosure, which retains complete formulation integrity so that only pure product is distributed. Among its many benefits, the bag-in-can system extends the shelf life of the product, suitable for all attitudes, (360-degree) expenditure, calm and non-cold discharge. This bag-in-can system is used in pharmaceutical, industrial, household, pet care and other products that require a complete separation between the product and the propellant.
The new development is a 2K aerosol (two components). 2K aerosol devices have the main components stored in the main room and the second component stored in the accessory container. When the applicator activates the 2K aerosol by breaking the accessory container, the two components will mix. Aerosol 2K can have advantages for the delivery of reactive mixtures. For example, a reactive 2K mixture may use low molecular weight monomers, oligomers, and low molecular polymer functioning to create a molecular weight polymer with the final cross-link. 2K aerosols can enhance solid contents and produce high-performance polymer products, such as curable paints, foams, and adhesives.
Security issues
There are three main areas related to health related to aerosol cans:
- The aerosol content may be intentionally inhaled to achieve intoxication of the propellant (known as inhalation or "huffing") harassment. Calling them "canned air" or "compressed air cans" can mislead fools into thinking they are harmless. In fact, death has resulted from such abuse.
- Aerosol burns can be caused by direct aerosol spraying onto the skin, in practice sometimes referred to as "frosting". Adiabatic expansion causes the aerosol content to cool down quickly when out of the can.
- Propellants in aerosol cans are usually a combination of unburned gases and are known to cause fire and explosion.
In the United States, non-empty aerosol cans are considered hazardous waste.
See also
- Fabrican
- Graffiti
- String Koolol
References
External links
- The Board of Consumer Aerosol Products
- Aerosol Sprays Can Contain Patents and Old Inventions
Source of the article : Wikipedia
0 Comments