Extrusion techniques Pumps

Alves-Filho, O., 2002. Combined innovative heat pump drying technologies and new cold extrusion techniques for production of instant foods. Diying Technol. 20(8) 1541-1557. 

The type of pumps used to dispense epoxy adhesives depends on whether it is a one-part or two-part adhesive. One-part epoxy adhesives are dispensed using direct metering extrusion pumps. An electric motor pushes a follower plate into a drum of adhesive, which is then extruded through a hose to the dispensing valve. This technique is used for medium-and high-volume production rates. 

Extrusion and impregnation, electrospinning, and multilayer films are other processes applicable for reinforced nanocomposites. Thus, preparation of cellulose whiskers reinforced with polylactic acid nanocomposites (by melt extrusion carried out by pumping the suspension of nanocrystals into the polymer melt during the extrusion process), using polyvinyl alcohol as a compatibilizer for the dispersion of cellulose whiskers within the polylactic acid matrix, was reported (de Menezes et al. 2009) bacterial cellulose whiskers incorporated into poly(oxyethylene) nanofibers by electrospinn to enhance the mechanical properties of electrospun fibers (Peresin et al. 2010) or the use of the layer-by-layer assembly technique, which maximizes the interaction between cellulose whiskers and a polar polymeric matrix (Bruno et al. 2009 Aulin et al. 2010), are some examples of nanocomposites reinforced by the last three methods. 

Poly-3,3-bis(chloromethyl)oxacyclobutane may be fabricated by injection moulding and extrusion it may also be applied as coatings by means of fluidized bed, solution or dispersion techniques. The majority of uses of the polymer are for articles which are required to withstand corrosive environments, especially at elevated temperatures. Typical applications include pump components, pipes and coatings for reactors and storage tanks. 

The deep reactive ion etching (DRIE) technique, first presented in the mid- to late 1990s, facilitated the fabrication of numerous innovative microsystems, especially power-MEMS systems. Since most MEMS devices involve some form of lithography-based microfabrication, the use of flat substrates is required. Often, these flat substrates involve the use of DRIE methods and result in structures characterized by extrusion of two-dimensional features into the third dimension as illustrated in Fig. 2. Therefore, microfluidic components are often limited in their geometrical appearance, which precludes full three-dimensional shapes commonly found in many large-scale fluidic devices such as pumps hydrofoils, turbine blades and vanes, mixers, etc. 

Techniques of supported extrusion are basically similar to those of the cross-head extrusion of rubber and plastic materials used by the wire and cable industries. The main difference is the absence of an extruder Liquid silicone rubber is pumped directly to a cross-head from the meter-mix unit or pressure pot. Curing is often carried out vertically using infra-red heaters or circulated hot air, but horizontal HAV units can also be used. A typical layout is shown in Fig. 7. The technology has been applied successfully to wire coating, optical fibres, ignition core, various tapes and to braided glass... 

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