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Impinging Mixer
Impinging mixers combine and disperse resins within each other, and are often used in reaction injection molding (RIM). Mixing occurs as two high velocity streams collide in a mixing chamber. High velocity results in a turbulent rather than a laminar flow. Impingement mixing is most effective when it occurs at the center of the mixing chamber. Thermosetting polymer, Thermosetting plastics cure by a chemical reaction between two resins. The resins must be mixed immediately before they are injected into a mold. The mixing can be done by impingement mixing, where two streams to collide at high velocity in a mixing chamber. As soon as the mixing chamber is full, a piston immediately pushes the mixed resin into the mold, leaving very little mixed resin curing outside the mold. References {{Engineering-stub Injection molding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reaction Injection Molding
Reaction injection molding (RIM) is similar to injection molding except thermosetting polymers are used, which requires a curing reaction to occur within the mold. Common items made via RIM include automotive bumpers, air spoilers, and fenders. Process The two parts of the polymer are mixed together, usually by injecting them under high pressure into an impinging mixer. Then the mixture is injected under lower pressure into a mold. The mixture is allowed to sit in the mold long enough for it to expand and cure. If reinforcing agents are added to the mixture then the process is known as reinforced reaction injection molding (RRIM). Common reinforcing agents include glass fibers and mica. This process is usually used to produce rigid foam automotive panels. A subset of RIM is structural reaction injection molding (SRIM), which uses fiber meshes for the reinforcing agent. The fiber mesh is first arranged in the mold and then the polymer mixture is injection molded over it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbulent
In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow, which occurs when a fluid flows in parallel layers, with no disruption between those layers. Turbulence is commonly observed in everyday phenomena such as surf, fast flowing rivers, billowing storm clouds, or smoke from a chimney, and most fluid flows occurring in nature or created in engineering applications are turbulent. Turbulence is caused by excessive kinetic energy in parts of a fluid flow, which overcomes the damping effect of the fluid's viscosity. For this reason turbulence is commonly realized in low viscosity fluids. In general terms, in turbulent flow, unsteady vortices appear of many sizes which interact with each other, consequently drag due to friction effects increases. This increases the energy needed to pump fluid through a pipe. The onset of turbulence can be predicted by the dimensionless Reyno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
European Federation Of Chemical Engineering
The European Federation of Chemical Engineering (EFCE), also known as Fédération Européenne du Génie Chimique and Europäische Föderation für Chemie-Ingenieur-Wesen, is an association of professional societies in Europe concerned with chemical engineering. It was formed in Paris on 20 June 1953 with 18 societies in 8 countries.''Trans IChemE, Vol 81, Part A,'' January 2003, pp 179-183 "European Federation of Chemical Engineering" India was the first non-European member in 1956 and Czechoslovakia the first Eastern European one in 1966. As of November 2016, it has 38 member societies in 29 countries joining 162000 individual chemical engineers. (Some countries have more than one member society). The EFCE passport programme allows members of one society some of the benefits of membership in other societies when travelling abroad, particularly for conferences. It has a set of 20 Working Parties and 5 Sections comprising about 1000 industrial and academic experts on different s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermosetting Polymer
In materials science, a thermosetting polymer, often called a thermoset, is a polymer that is obtained by irreversibly hardening (" curing") a soft solid or viscous liquid prepolymer (resin). Curing is induced by heat or suitable radiation and may be promoted by high pressure, or mixing with a catalyst. Heat is not necessarily applied externally, but is often generated by the reaction of the resin with a curing agent (''catalyst'', ''hardener''). Curing results in chemical reactions that create extensive cross-linking between polymer chains to produce an infusible and insoluble polymer network. The starting material for making thermosets is usually malleable or liquid prior to curing, and is often designed to be molded into the final shape. It may also be used as an adhesive. Once hardened, a thermoset cannot be melted for reshaping, in contrast to thermoplastic polymers which are commonly produced and distributed in the form of pellets, and shaped into the final product form b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
