Buying and Selling New, Used and Reconditioned Extruders and Extruding Equipment
We buy and sell used, unused and reconditioned Single Screw and Twin Screw EXTRUDERS, including EXTRUDERS manufactured by: Berstorff, Leistritz, Davis Standard, Deltaplast, Welex and many others.
Extruders are typically used to turn solid plastic into a uniform melt through the heating, pressure and shear. The melt includes mixing a master-batch and other additives such as resin, and then smashing in the production process. The finished melt must be homogeneous in concentration and temperature. The pressure must be high enough for viscous polymer extrusion.
Extruder completes all of the above process through the barrel with a spiral track and a screw. Plastic pellets are fed through a hopper at one end of the barrel into the barrel, and then transmitted to the other end of the barrel by a screw. The thread depth of screw starts to decrease with the increase distance of the hopper to ensure sufficient pressure. External heating and the internal heat generated by friction in the plastic and the screw make plastic soften and melt. Different polymers and applications have various design requirements of the extruder.
The extrusion machine is normally composed by at least three segments. The first part is feeding zone near the hopper. This part can push the material into the extruder at a relatively steady rate, which will maintain relatively low temperature to avoid clogging of the feeding channel. The second part is divided into the compression zone which forms a melt and increases the pressure. The transition can be sudden or gradually (gentle) from the feed zone to the compression section. The last part is the metering zone close to the outlet of the extruder. The main function is to maintain uniform material from the outflow of the extruder. And the material should have a sufficient residence time to ensure the uniformity of the composition and temperature.
The drive mechanism controls the rotational speed of the screw which determines the output of the extruder. The required power is determined by the viscosity of the polymer (flow resistance) which depends on the temperature and the flow rate.
There are two types of extruders: Single Screw Extruders and Twin Screw Extruders.
If you are looking for a complete plastic plant such as a polypropylene plant, pvc plant, polyethylene plant (hdpe or ldpe) or other chemical process in which an extruder is a major piece of equipment, please click here to view complete chemical and plastic processing plants we are selling.