Variable rate dispensing system for abrasive material and method thereof

A method of regulating a flow rate for an abrasive material dispensed in an abrasive jet apparatus, the method comprising the steps of:

• a. establishing an abrasive dispenser defining a compartment for storing a granular abrasive material;
• b. establishing in said abrasive dispenser at least one metering orifice disposed in open communication with said compartment for dispensing the granular abrasive material;
• c. establishing a shutter member adjacent said metering orifice of said abrasive dispenser, said shutter member having at least one shutter opening formed therethrough, said shutter member being angularly displaceable between first and second positions relative to said metering orifice, said shutter opening being substantially fully aligned with said metering orifice in said first position and substantially fully offset therefrom in said second position;
• d. reversibly displacing said shutter member to said first and second positions and a plurality of intermediate positions therebetween for occluding a selective portion of said metering orifice;
• and,
• e. adaptively controlling said shutter member displacement to maintain a flow rate of the abrasive material dispensed through said metering orifice at a predetermined level.

An abrasive jet apparatus comprising:

• an abrasive dispenser defining a compartment for storing a granular abrasive material and at least one arcuate metering orifice disposed in open communication therewith for dispensing the granular abrasive material;
• a shutter assembly disposed adjacent said metering orifice of said abrasive dispenser, said shutter assembly including a shutter member angularly displaceable between first and second positions relative to said metering orifice, said shutter member having at least one arcuate shutter opening formed therethrough, said shutter opening being substantially fully aligned with said metering orifice in said first position and substantially fully offset therefrom in said second position;
• and,
• a position actuator operatively coupled by a substantially tubular drive shaft member to said shutter mechanism for reversibly displacing said shutter member to said first and second positions and a plurality of intermediate positions therebetween for occluding a selective portion of said metering orifice, said drive shaft member defining an axial bore for conducting a stream of air induced therethrough, whereby a flow rate of the abrasive material dispensed through said metering orifice is maintained at a predetermined level.