| 摘要 |
Apparatus which controllably meters dry powder from a powder supply chamber falling through a vertically disposed axial passageway interconnecting the supply chamber with a mixing chamber therebelow for forming an air-powder mixture therein for transport to a desired site. A tapered plug member is bonded to a bimorph bender comprising a piezoelectric element bonded to each face of a thin, flat, cantilevered metallic beam which is deflectable by a dc bias or driving voltage applied to the bender to cause the tapered plug to penetrate or move within the passageway, thus varying width of annular gap formed between the plug and passageway, and hence, amount of powder capable of falling therethrough. An oscillating voltage may be impressed upon the piezoelectric elements to cause the deflected beam to additionally be vibratorily displaced in accordance with the frequency of vibrations of the impressed oscillating source.
|
