Vacuum Pumps For Plastic Extrusion

Plastic extrusion begins with plastic chips, beads or pellets - often referred to as resin. The resin, along with additives such as colorants and UV inhibitors, is fed from a hopper into the barrel of the extruder.

The resin is pushed by the screw extruder towards the barrel where it is heated at around 400°F (200­°C) to a molten state. As the material nears the end of the screw, the melt is unpressurized, and NASH vacuum pumps are used to vent the trapped gases. The gases need to be vented because they could create voids and other imperfections in the finished product. 

Once through the breaker plate, the plastic - still in its molten state - enters the die, which gives it the final profile. The extrudate is then cooled and solidified as it is pulled through a water tank. In a tube or pipe extrusion line, a sealed water bath has a carefully controlled vacuum applied to keep the molten tube or pipe from collapsing.

NASH liquid ring vacuum pumps are ideal for this application because they handle intermittent and continuous streams of water without damage or loss of vacuum level and are tolerant of plastic resin carryover.