Process and apparatus for compressing, and monitoring the compression of, pulverulent materials and a press applying same

A compaction press for compressing doses of pulverulent materials which are compacted in a container by a punch comprising

• (a) a chassis rising generally vertically from a table;
• (b) a jack attached to the chassis and having a generally vertically oriented extendible and retractable piston rod;
• (c) a support frame slidably mounted on the chassis and operatively associated with the piston rod of the jack so as to be displaced by movement of the piston rod;
• and,
• (d) at least one spindle assembly attached to the support frame, each spindle assembly comprising:
• (i) a monitoring spindle;
• (ii) means operatively connecting the punch to the spindle;
• (iii) a screw nut drive system having a driving member to move the punch so as to compact the pulverulent material;
• (iv) a housing having monitoring sensor means to monitor the force of compression exerted on the pulverulent material by the punch, the housing being operatively associated with the spindle and interposed between the screw nut driven system and the punch, and adapted to be displaced by the screw nut drive system;
• and,
• (v) servo-control circuit means operatively connected to the monitoring means and the screw nut drive means such that the force of compaction is between predetermined minimum and maximum values.

A method of controlling an apparatus for compressing doses of pulverulent material which are compacted in a container by a punch comprising the steps of:

• (a) fixing a reference value of at least one of the force of compaction, and the compacted height of the does to be attained less than a corresponding maximum value;
• (b) controlling the displacement of the punch until at least one of the force of compaction and the compacted height has reached the corresponding reference value;
• (c) after the reference value of the force of compaction is reached, measuring the maximum force of compaction achieved during the compacting cycle;
• (d) measuring the residual force of compaction to examine the evolution thereof;
• and,
• (e) controlling displacement of the punch based upon at least one of the measured maximum force of compaction and measured residual force of compaction.