Are commercial purging compounds safe to be left in the barrel?
This is a good question because purging before shutting down makes for an easier start–up. Among the three types of purging compound, only thermoplastic mechanical non–abrasive are safe to be left in the barrel for shutdown. The chemical types are only active for the period of time during the purging process. It is important that all chemical residual be removed before shutdown for the protection of the equipment. The mechanical abrasive will freeze in the barrel, and left in the barrel, may result in damage to the screw on start-up. Dyna–Purge is a thermoplastic mechanical non–abrasive purging compound that can be used for shutdown and start–up. We recommend that the machine be purged with Dyna-Purge at shutdown to clean, and that the barrel be filled with Dyna–Purge during shutdown. Dyna–Purge is very stable — it will not degrade upon start–up. Dyna–Purge ensures that start–ups will be easier and faster than with other types of purging compounds.
