| 摘要 |
A metering device includes an inlet and outlet for a material (liquids, gases or solid particles) to be metered, a rotatable ball driven by a shaft and interposed between the inlet and outlet seats. The rotatable ball has a transverse bore containing a sealess shuttling member which can reciprocate back and forth along the bore between two sealing seats so as to seal against one or the other. The sealess shuttling member is propelled by pressurized material which flows into the bore without surface-to-surface contact of the shuttling member with the bore wall until is engages one of the two sealing seats. Each time the rotatable ball rotates 180 DEG , a metered shot is ejected resulting in a quasi continuous flow depending upon a rotatable ball revolution rate.
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