New airlock design takes the heat
When Tennessee Eastman needed airlocks that wouldn't leak or bind between the rotors and housings when feeding hot plastic pellets, a new design that allows on-line adjustment of the rotor-to-housing clearance solved the company's problem.
Tennessee Eastman, located in Kingsport, Tenn., produces chemicals, fibers, and plastics, including 1/8-inch polyethylene teraphthalate [PET] pellets used to manufacture plastic beverage containers. Several identical process lines perform the final, polishing stage of the PET pellet production. In each process line, the pellets go from a feed bin operating at ambient temperature and pressure into a rotary airlock, which feeds them into a polishing reactor operating at high temperature and about 10 lb/in2 pressure. From the reactor, the PET pellets go through another rotary airlock into a cooler operating at low temperature and pressure, then through a final rotary airlock into a product bin operating at ambient temperature and pressure.