초록 ▼

A pressurized feeder vessel feeds powdered material into a stream of propellant gas. The feeder vessel includes a funnel-shaped hopper that is resiliently suspended by an elastic member inside the vessel. A vibrator such as an electric motor with an eccentric weight on its shaft vibrates the bottom

A pressurized feeder vessel feeds powdered material into a stream of propellant gas. The feeder vessel includes a funnel-shaped hopper that is resiliently suspended by an elastic member inside the vessel. A vibrator such as an electric motor with an eccentric weight on its shaft vibrates the bottom end of the hopper. The vibration forces of the vibrator are preferably transferred to the hopper via a flexible diaphragm. The hopper is thus subjected to primary vibration forces and torques from below, and secondary, reaction vibration forces and torques from above. This induces the powder in the hopper to fluidize thoroughly and to circulate. In particular, it circulates over and past an inlet orifice, through which powder exits the hopper and enters the propellant stream. Powder circulation thus also prevents clogging of the inlet orifice and leads to more even flow rates. The invention is particularly well suited for delivering abrasive powder to a hand-held dental tool for abrasive treatment of teeth.

대표청구항 ▼

An arrangement for delivering powdered material under pressure comprising: A. a source of pressurized propellant gas; B. a pressure vessel that is connected to the source of pressurized propellant gas via a pressure inlet and that has a pressurized outlet; C. a mainly funnel-shaped hopper that is mo

An arrangement for delivering powdered material under pressure comprising: A. a source of pressurized propellant gas; B. a pressure vessel that is connected to the source of pressurized propellant gas via a pressure inlet and that has a pressurized outlet; C. a mainly funnel-shaped hopper that is mounted within the pressure vessel, that holds the powdered material, and that has a top portion and a bottom portion; D. an inlet orifice through which the powdered material exits the hopper and enters the pressurized outlet line; E. a suspension resiliently supporting the hopper within the pressure vessel; and F. a vibration means for applying oscillatory forces and torques to the bottom portion of the hopper and thereby for causing the powdered material in the hopper to fluidize and circulate within the hopper and across the inlet orifice; in which the suspension is an annular elastic member that contacts the hopper around the top portion of the hopper and is fastened to an inner surface of the pressure vessel.