Stage grinding with hammer mill and crushing roller mill.

摘要

The optimization of the particle size structure of a pig feed mixture with a high barley content by means of stage grinding with hammer mill and downstream crushing roller mill was conducted. The following variants were compared: (1) crushing roller mill twice; (2) stage grinding hammer mill with pre- and post-mill; and (3) stage grinding with hammer and crusher roller mills. Contrary to the hammer mill, by means of roller crushing, the fines content in the finished product <0.5 mm can be reduced considerably to below the target value of 25%. However, to both reduce the fines content and achieve a high percentage within the medium range of 0.5 to 1.6 mm, the combined stage grinding with hammer mill and crushing roller mill was more suitable, since in this case the coarse fraction, i.e., husks, will be reduced sufficiently. Results of preliminary tests showed that the arrangement, hammer mill first then the crusher roller mill' was more appropriate than the reverse order, since post-grinding with the hammer mill produces more fines than post-grinding with the crushing roller mill. The use of a crushing roller mill, whether in combination with a hammer mill or not, produces in all cases a significant reduction of the specific energy consumption in the range of 30 to 50%.