| 摘要 |
<p>The blast cleaning unit is for use by dental surgeons, and may be deployed to clean fresh castings e.g. for false teeth, and may use corundum grit projected by compressed air. The treatment is effected in a glove-box, and a tapping (26) from the compressed air feed (18) is used to promote a controlled internal flow of grit-laden air. The arrangement prevents an escape of grit-laden air when the box (11) is opened to retrieve the workpiece. The unit comprises a treatment chamber (11) within a housing (10). The chamber (11) contains the jet (15) which is fed to a mixture of compressed air (18) and grit (14). The tapping (26) issues (27) in a vol. (20) adjacent to the chamber (11) and which communicates (23) with the chamber whilst being capable of ventilation. The tapping (26) has a secondary jet (28) which causes an air flow through a baffle (24) into a stilling chamber (25) and through screens (36). Controls may include valves (29, 35) for the respective air feeds and electric switches (33, 34).</p> |
