Patent ID: 6857322

Claim:
A process for the continuous production of a polymer powder, comprising continuously producing a polymer powder in a reactor for gas-phase polymerization in the presence of a polymerization catalyst, and during said production controlling at least one operating parameter thereof by measuring a compressibility value K of a hot powder produced, this compressibility measurement comprising the following steps: filling a graduated vertical container with a volume V 1 of hot powder, so that an upper surface of this powder volume is plane and horizontal; placing a piston on this upper powder surface, this piston being guided vertically and sliding freely inside the container and the cross section of the piston having a shape identical to that of the container and being slightly smaller in size; leaving the piston for a sufficient time to compress the hot powder by the effect of the weight of the piston; measuring a volume V 2 of hot powder thus compressed; and calculating the compressibility value K (%) by the equation K=((V 1 -V 2 )/V 1 )*100.