Abstract: A spool valve for use with pressurized fluid to control components of a control system. The spool valve has two stable positions in one of which the spool is firmly held by pressurized fluid.

Abstract: Apparatus for providing a continuous flow of fluent particulate material suspended in a gaseous stream from a bulk source. The pneumatically powered and controlled apparatus includes a material receiving chamber intermittently replenishing a second chamber operable to maintain a third or material dispensing chamber adequately charged at all times. The apparatus controls are responsive to the material level sensing means in the second chamber to initiate a recharging cycle when the material therein falls below a predetermined level.

Abstract: Improved apparatus for the transportation of granular materials such as concrete is disclosed. The apparatus includes a pneumatic discharge area, a rotatable feed wheel having a plurality of pockets opening to a hopper for transporting increments of material to the discharge area and vibrating apparatus including one or more resilient members disposed adjacent the openings to the feed wheel pockets for being alternately flexed and released to impart vibration to the resilient members to enhance the flow of material into the pockets. The vibrating apparatus further includes a mounting ring, adapted for mounting in the device, and one or more inwardly extending mounting bars affixed to the ring for carrying the resilient members.