Holman dust extractor

Holman dust extractor

[′hōl·mən ′dəst ik‚strak·tər]
(mining engineering)
A dust-trapping system in which the dust and chippings from percussive drilling operations are drawn back through the hollow drill rod and along a hose to a metal container with filter elements.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.