Abstract: A particle blast cleaning apparatus incorporates a pressurized container which is pressurized by the transport gas upon start up through a feeder which does not comprise an airlock. The feeder introduces the blast media into the transport stream. At start up, the transport gas pressurizes the container, flowing upwardly through the feeder until the container is substantially pressurized and the flow substantially ceases. The feeder rotor may be configured to crush or grind the particles.

Abstract: A particle blast cleaning apparatus incorporates a pressurized container which is pressurized by the transport gas upon start up. A feeder introduces the blast media into the transport stream.

Abstract: Apparatus to prepare an airstream laden with particles of solid dry ice. A rotor has passages which sequentially pass a source of particles and a source of air under pressure to prepare the airstream and send it to a nozzle. The rotor is held between pads whose force against the rotor is a function of air supply pressure. The speed of the rotor and of the particle feed are controllable, and the air feed persists after particle feed has stopped for a period of time sufficient to clear particles from the rotor.

Abstract: A granulator and delivery system for sublimable CO.sub.2 granules has working edges rotatably supported for defining a cutting surface; a driver for powering the working edges; a feeder for advancing solid CO.sub.2 into contact with the working edges, the working edges removing the granules from the solid CO.sub.

Abstract: Apparatus for enhancing the feeding of particles includes a hopper having a central axis, walls of the hopper being concentric with the hopper axis above an outlet of the hopper; a sensor for sensing a desired flow of particles from the hopper; a shaft rotatably mounted on the hopper axis; a paddle connected to the shaft and extending from approximately 0.125 inch to approximately 0.250 inch from at least a lower portion of an inside surface wall of the hopper, the shaft being rotated at approximately 1 radian per second in response to a drive signal; the drive signal being momentarily activated in the presence of an external activate signal when the flow of particles falls below the desired rate, the drive signal being active for a period of time sufficient to cause the paddle to move through an angle of about 90.degree. about the hopper axis. The paddle is mechanically agitated during feeding of the particles, the paddle vibrating only during activation of the external signal, with a displacement of from 0.

Abstract: Disclosed is an improved pelletizer and delivery system for hygroscopic and deliquescent materials, pellets being formed by a rotary extrusion mechanism that receives the material in the form of snow from a snow chamber, the system having a pair of scraper members for preventing undesired snow build-up on inside walls of the snow chamber, the scraper members operating in a scissors manner for preventing snow build-up on the scraper members. Carbon dioxide gas from the snow chamber can be used for pressurizing a pellet collector that is located under the extrusion mechanism for smoothly and gently feeding the pellets at least 15 feet horizontally to a receiving hopper, the gas pressure within the collector also enabling delivery of the pellets several feet above the bottom of the collector. The pellets can be delivered in excess of 150 feet horizontally from the collector.

Abstract: A system (10) for delivering a cold particulate material (14) has a closed storage hopper (12) for the material, the hopper having a bottom hopper outlet (16); a venturi feeder (22) having a material inlet (20) for feeding the material, a material conduit (26) to a remote nozzle (30), and a gas inlet (24); a hopper passage (18) connecting the hopper outlet to the feeder material inlet; a gas feed valve (33), the gas feed valve being openable in response to a feed signal (40) for activating the feeder and a blast conduit to the nozzle; a heater (50) in the blast conduit for limiting cooling of a workpiece without adversely heating the material; and a comminutor (52) in the material line proximate the nozzle for delivery of the material at reduced particle size to the nozzle for increased blasting effectiveness.

Abstract: A system for delivering a particulate material has a closed storage hopper for the material, the hopper having a bottom hopper outlet and a check valve connected to a top portion of the chamber for venting positive pressure from the chamber; a venturi eductor having a material inlet for feeding the material, an eductor outlet, and a gas inlet; a gas feed valve, the gas feed valve being openable in response to a feed signal for activating the eductor; a hopper passage connecting the hopper outlet to the eductor material inlet; a hopper outlet valve for closing the hopper outlet in response to a hopper signal; a stir valve for pressurizing the hopper passage in response to a stir signal for agitating the material in the hopper; and a pressure sensor for momentarily activating the stir signal in response to an absence of the material at the material inlet, the system being operative in a transporting mode wherein the hopper valve is open, the feed valve is open, and the stir valve is closed; a stirring mode wher