Patent ID: 6346035
Filing Date: 2002-02-12
Classification: B24C

Abstract:
Particulate blasting apparatus comprising:an adjustable variable speed metering element delivering particles of solid carbon dioxide at a selected rate; an air lock element comprising a rotor having a central axis of rotation, an upper and a lower flat rotor surface axially separated from one another, and parallel to one another, a plurality of separate rotor ports disposed in a ring array around said axis, extending between said rotor surfaces; an upper and a lower non-rotating pad each having a flat surface bearing against a respective upper and lower rotor surface, an upper and lower pad holder, said upper pad holder having a particle port disposed to receive particles and discharge said particles to rotor ports as they pass said particle port, and an air port disposed to receive air under pressure and discharge air to said rotor ports as they pass said air port, said lower pad holder having a receiving port aligned with said air port disposed to receive the contents of rotor ports as they pass said receiving port together with air from said air port; a chute for discharging particles from said metering element to said particle port; air supply means for providing air under adjustable pressure to said air port in said upper pad; and bias means for biasing said pads against said rotor; said bias means comprising a pneumatic cylinder whose bias pressure is proportional to the pressure of the air supplied to the air lock.