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Pinch Valve
A pinch valve is a full bore or fully ported type of control valve which uses a pinching effect to obstruct fluid flow. Operating principle Pinch valves employ an elastic tubing (sleeve/hose) and a device that directly contacts the tubing (body). Forcing the tubing together will create a seal that is equivalent to the tubing's permeability. Air-operated pinch valves consist of an elasticised reinforced rubber hose, a type of housing, and two socket end covers (or flanges). In air-operated pinch valves, the rubber hoses are usually press-fitted and centered into the housing ends by the socket covers. There is no additional actuator, the valve closes as soon as there is a pressurized air supply into the body. When the air supply becomes interrupted and the volume of air exhausts, the elastic rubber hose starts to open due to the force of the process flow. Fields of application Pinch valves are typically used in applications where the media needs to be completely isolated fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastics
Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptability, plus a wide range of other properties, such as being lightweight, durable, flexible, and inexpensive to produce, has led to its widespread use. Plastics typically are made through human industrial systems. Most modern plastics are derived from fossil fuel-based chemicals like natural gas or petroleum; however, recent industrial methods use variants made from renewable materials, such as corn or cotton derivatives. 9.2 billion tonnes of plastic are estimated to have been made between 1950 and 2017. More than half this plastic has been produced since 2004. In 2020, 400 million tonnes of plastic were produced. If global trends on plastic demand continue, it is estimated that by 2050 annual global plastic production will reach over 1,1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium
Aluminium (aluminum in AmE, American and CanE, Canadian English) is a chemical element with the Symbol (chemistry), symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has a great affinity towards oxygen, and Passivation (chemistry), forms a protective layer of Aluminium oxide, oxide on the surface when exposed to air. Aluminium visually resembles silver, both in its color and in its great ability to reflect light. It is soft, Magnetism, non-magnetic and ductility, ductile. It has one stable isotope, 27Al; this isotope is very common, making aluminium the twelfth most common element in the Universe. The radioactivity of Aluminum-26, 26Al is used in Radiometric dating, radiodating. Chemically, aluminium is a post-transition metal in the boron group; as is common for the group, aluminium forms compounds primarily in the +3 oxidation state. The aluminium cation Al3+ is small and h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Butyl Rubber
Butyl rubber, sometimes just called "butyl", is a synthetic rubber, a copolymer of isobutylene with isoprene. The abbreviation IIR stands for isobutylene isoprene rubber. Polyisobutylene, also known as "PIB" or polyisobutene, (C4H8)n, is the homopolymer of isobutylene, or 2-methyl-1-propene, on which butyl rubber is based. Butyl rubber is produced by polymerization of about 98% of isobutylene with about 2% of isoprene. Structurally, polyisobutylene resembles polypropylene, but has two methyl groups substituted on every other carbon atom, rather than one. Polyisobutylene is a colorless to light yellow viscoelastic material. It is generally odorless and tasteless, though it may exhibit a slight characteristic odor. Properties Butyl rubber has excellent impermeability to gas diffusion, and the long polyisobutylene segments of its polymer chains give it good flex properties. The formula for PIB is: –(–CH2–C(CH3)2–)n– The formula for IIR is: It can be made from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neoprene
Neoprene (also polychloroprene) is a family of synthetic rubbers that are produced by polymerization of chloroprene.Werner Obrecht, Jean-Pierre Lambert, Michael Happ, Christiane Oppenheimer-Stix, John Dunn and Ralf Krüger "Rubber, 4. Emulsion Rubbers" in Ullmann's Encyclopedia of Industrial Chemistry, 2012, Wiley-VCH, Weinheim. Neoprene exhibits good chemical stability and maintains flexibility over a wide temperature range. Neoprene is sold either as solid rubber or in latex form and is used in a wide variety of commercial applications, such as laptop sleeves, orthopaedic braces (wrist, knee, etc.), electrical insulation, liquid and sheet-applied elastomeric membranes or flashings, and automotive fan belts. Production Neoprene is produced by free-radical polymerization of chloroprene. In commercial production, this polymer is prepared by free radical emulsion polymerization. Polymerization is initiated using potassium persulfate. Bifunctional nucleophiles, metal oxides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrile
In organic chemistry, a nitrile is any organic compound that has a functional group. The prefix '' cyano-'' is used interchangeably with the term ''nitrile'' in industrial literature. Nitriles are found in many useful compounds, including methyl cyanoacrylate, used in super glue, and nitrile rubber, a nitrile-containing polymer used in latex-free laboratory and medical gloves. Nitrile rubber is also widely used as automotive and other seals since it is resistant to fuels and oils. Organic compounds containing multiple nitrile groups are known as cyanocarbons. Inorganic compounds containing the group are not called nitriles, but cyanides instead. Though both nitriles and cyanides can be derived from cyanide salts, most nitriles are not nearly as toxic. Structure and basic properties The N−C−C geometry is linear in nitriles, reflecting the sp hybridization of the triply bonded carbon. The C−N distance is short at 1.16 Å, consistent with a triple bond. Nitril ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Rubber
Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and Indonesia are three of the leading rubber producers. Types of polyisoprene that are used as natural rubbers are classified as elastomers. Currently, rubber is harvested mainly in the form of the latex from the rubber tree (''Hevea brasiliensis'') or others. The latex is a sticky, milky and white colloid drawn off by making incisions in the bark and collecting the fluid in vessels in a process called "tapping". The latex then is refined into the rubber that is ready for commercial processing. In major areas, latex is allowed to coagulate in the collection cup. The coagulated lumps are collected and processed into dry forms for sale. Natural rubber is used extensively in many applications and products, either alone or in combination ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synthetic Polymer
Some familiar household synthetic polymers include: Nylons in textiles and fabrics, Teflon in non-stick pans, Bakelite for electrical switches, polyvinyl chloride (PVC) in pipes, etc. The common PET bottles are made of a synthetic polymer, polyethylene terephthalate. The plastic kits and covers are mostly made of synthetic polymers like polythene, and tires are manufactured from Buna rubbers. However, due to the environmental issues created by these synthetic polymers which are mostly non-biodegradable and often synthesized from petroleum, alternatives like bioplastics are also being considered. They are however expensive when compared to the synthetic polymers. Inorganic polymers * Polysiloxane * Polyphosphazene * Polyborazyline Organic polymers The eight most common types of synthetic organic polymers, which are commonly found in households are: *Low-density polyethylene (LDPE) *High-density polyethylene (HDPE) *Polypropylene (PP) * Polyvinyl chloride (PVC) * Po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
