Abstract: A plenum drying hopper for granular material includes a housing enclosing a plenum chamber, an upper material inlet for introducing a flow of granular material into the plenum chamber, and a perforate diffuser cone, located in the lower portion of the plenum chamber, that directs the granular material from the plenum chamber into a material outlet. The perforations in the diffuser cone are large enough to permit ready passage of gas therethrough but small enough to preclude passage of all but the finest particles of the granular material. A gas inlet extends into the lower portion of the housing for introducing a drying gas (air) into the plenum chamber; a gas outlet discharges the gas from the upper part of the housing. Heaters are provided for heating the gas prior to its entry into the plenum chamber.

Abstract: A vacuum storage hopper for storing and dispensing granular materials, including a storage chamber having a lower inverted conical discharge section terminating in a discharge valve. At least one material inlet and a combination air inlet-outlet are connected to the upper part of the storage chamber. A source of air under vacuum and pressure is connected to the air inlet-outlet for exhausting air from the storage chamber to draw granular material thereinto, and for supplying air under pressure to the storage chamber to assist the discharge of granular material from the hopper. A flexible, resilient air-impervious membrane of inverted generally conical configuration is located in the discharge section of the hopper; the membrane has its upper edge secured to the upper edge of the discharge section of the hopper and hangs downwardly therefrom. A short strip of the membrane, no more than a minor fraction of its circumference, is secured to the storage chamber below its upper edge.

Abstract: A versatile control for a plural-material vacuum hopper loader comprising a blowback timer which generates a blowback enabling signal for a time interval T2, a blowback signal generator which develops a series of blowback pulse signals of adjustable duration, and blowback logic which actuates an air supply to apply pulses of air to the hopper loader during interval T2. A fill timer generates a fill enabling signal over a time interval T3, and a fill signal generator develops a repeating sequence of fill actuating signal pulses of adjustable relative duration; the fill enabling signal energizes an evacuation apparatus to evacuate the hopper continuously during interval T3 whereas fill logic actuates fill control valves (one for each material) in the repeating sequence of the fill actuating signal pulses throughout the same interval.

Abstract: A regeneration cycle control for a dessicant air dryer of the kind in which regeneration is effected by passing heated air through the bed; a thermal sensor senses the bed outlet temperature and de-energizes the regeneration air heater when a given outlet temperature T1 is reached, after which regeneration air flow is continued to cool the bed to a lower temperature T2, at which point the regeneration cycle is terminated and on-stream operation resumed. In a dual-bed dryer, the beds are maintained alternately in on-stream mode and regeneration mode.

Abstract: Pneumatic conveyor apparatus for conveying particulate material in successive plugs separated by gas-filled spaces, comprising a take-off chamber connecting a supply source to a pressurizing chamber through an internal port, a valve rod and valve closure member for closing the port between the two chambers, a valve actuator connected to an extension of the rod outside the two chambers, a main gas supply for supplying gas under pressure into the top of the pressurizing chamber, and control means for cyclically energizing and de-energizing the valve actuator and the main gas supply, closing the port and supplying gas to the pressurizing chamber and then opening the port with the main gas supply shut off. A cylinder encompasses the valve rod extension, and a continuous flow of gas is maintained through the cylinder into the transfer chamber. The valve closure member has a conical elastomer surface facing a sharp valve seat at the internal port, affording free flow in a self-cleaning valve.