Washing installation and accessories
The machinery and/or accessories that make up washing installations for thermoplastic and other materials may consist of a variety of modular units including a “friction washer”, “centrifuge”, “spin dryer”, “hydrodynamic separation tank”, “drying presses”, “hot air fluid bed drying systems”, etc.
Friction washer: this is a washing centrifuge positioned horizontally or vertically as needed. It is used for thorough washing of the material introduced, in a water bath by high mechanical friction products by the particular design of the rotor. The machine is built so that all the parts in contact with the material are entirely made of AISI 304L stainless steel. In case of particular requirements, for example when processing PET, the machine can wash in a water bath heated to 85/90° C with the addition of detergents.
Spin dryer: this is a drying centrifuge positioned horizontally or vertically as needed. The machine is designed to separate the material from the fluid in which it has been treated. The rotor, drainage basket and machine body can be shaped differently depending on the granulometry, density and productivity required. With these machines it is possible to reach production rates of up to 3000/4000 kg/h with varying percentages of output moisture ranging from 1.8% to 6% depending on the type of material introduced at the beginning of the cycle, for example: films, ground material, foam, flakes, etc.
Hydrodynamic separation tank: make entirely of AISI304L stainless steel, this machine serves for separation by floatation of thermoplastic materials that have to be finished, from those that have to be discarded. Floatation can be achieved using water (1 kg/dmc) or other fluid containing salts (1.1 – 1.2 kg/dmc). The tank size will depend on the quantity and quality of materials to be processed. The progress of the material through the tank can be achieved using large immersion drums, if the material to be finished tends to float, or screws with single and/or double spiral installed on the bottom, if the material tends to sink. The tank is also equipped with a special infeed screw that doses the incoming material, as well as special evacuators on the bottom, sides or at the head of the tank . The floatation system and heating of the material is hydrodynamic with controlled filtration and introduction of the fluid.
Drying press: built like an extruder, the machine presses the material introduced, using a large compacting screw constructed entirely in a solid bar, that presses it against the drainage basket and against a special outlet opening . The expulsion system is hydraulic, with electronic control to maintain a constant output pressure and ensure perfect drying, while preventing any possible plastification of the material inside the screw of the compacting chamber.
Fluid bed drying system: all the parts in contact with the material are constructed in AISI 304 stainless steel and are insulated with a layer of rock wool covered by a sheet of aluminum. The material is dried by fluctuation on a fluid bed of hot air heated by batteries and/or a gas boiler. In case of use of a current generator, it is possible to heat the air necessary for the dryer using an air/air heat exchanger that takes advantage of the high temperature of the discharge gasses from the generator.