Cooled tangential pins

The new TPT range of cooled tangential pin extruders patented by Colmec (hall 16, stand E59) will be unveiled at K 2013. They are the natural evolution of the pin extruders that have been used for several decades by rubber products manufacturers, especially in the tyre industry, for tasks such as: calender feeding; compound filtering; extrusion of semi-finished profiles to be laminated in downstream process stages such as, for example, the co-extrusion of tread bands and sidewalls. Sporadically, these extruders are also used for the production of finished profiles vulcanised in continuous, where traditional pinless extruders are still considered the best solution.
The TPT extruders are characterised by the presence of pins arranged tangentially in the plasticising barrel close to the corresponding notches on the screw, whose function is to increase the flow rate to counter back flow phenomena as well as to facilitate the rubber plasticisation process. The new technology aims at optimising the characteristics of traditional extruders improving temperature control and thus making it suitable for any application. The innovation consists in a special extrusion barrel that can incorporate the cooled tangential pins. The pin cooling subtracts a substantial amount of energy to the compound processed, thus allowing the screw speed to be increased while maintaining low extrusion temperatures.
These extruders have passed the experimental stage and basically their industrialisation is now accomplished, as some units are already being employed by Italian and foreign processors with positive results. The continuous running over three shifts has confirmed their competitiveness in the production of profiles, tubes and tyre bands as well as in calender feeding. The TPTs are available with a diameter of 90, 120, 150, 200 or 250 mm. Moreover Colmec also offers the possibility to retrofit conventional extruders produced by other manufacturers by replacing old barrels and extrusion screws.