Abstract: The invention concerns a system for controlling an aircraft propeller. A hydraulic motor controls pitch of the propeller blades. The propeller blades are characterized by the absence of feather-inducing counterweights. An overspeed governor senses when propeller speed exceeds a limit, and, in response, assumes control of the hydraulic motor and drives the blades toward a coarsened pitch position, which reduces the propeller speed. In another form of the invention, a mechanical brake can override the hydraulic motor and mechanically retard a rotating gear, which causes the propeller blades to move toward a coarsened pitch.

Abstract: A fuel control apparatus for supplying metered fluid at a variable pressure to a turbine engine in response to an electrical signal. A solenoid responds to the electrical signal to vary the flow rate of the fluid to an outlet and to regulate the pressure differential across an orifice as a function of the flow rate.

Abstract: A filter includes a bed of particulate solids for removal of contaminants from a fluid directed in a downstream direction therethrough. A barrier is located downstream of the bed of particulate solids and includes an anchoring member having flexible members joined thereto and projecting outwardly therefrom. The flexible members are closely spaced to each other for providing a closely-spaced network of flexible members to establish multiple barrier layers in the downstream direction of fluid flow through the barrier. In one embodiment the barrier is in the form of a planar member generally coextensive with a bottom wall of the filter and includes a plurality of anchoring members spaced-apart horizontally from each other. In another embodiment the barrier is in the form of a strainer with the anchoring members being spaced-apart vertically from each other and with the flexible members joined thereto being spaced transversely along the anchoring members to provide the multiple barrier layers.

Abstract: A filter block used in the construction of a multi-block filter bottom includes upper and lower lateral sections extending between end walls and being separated from each other by a horizontal petition that includes ports for communicating the upper and lower lateral sections with each other. A removable top wall section includes passages through it for communicating with the upper lateral section, and fastening means are provided for removably securing the top wall section to the remainder of the block.

Abstract: An upflow filter of the type in which a liquid influent (e.g. water) is directed upwardly through buoyant filter media particles includes a porous supporting member, preferably in the form of a screen having openings through it that are larger than the nominal size of the media particles. A layer of particulate material is positioned on the upper surface of the porous supporting member and has a nominal particle size that is greater than the size of the openings through the supporting member. This layer of particulate material includes a plurality of interstices, or passages through which filtered liquid influent can pass, and, in the most preferred embodiment, also retains the buoyant media particles in the filter.

Abstract: An improved rigid filter plate for sludge dewatering is comprised of a filter element of two or more sizes within the range of 0.2 to 0.002 inch of irregular hard particles of aluminum oxide or similar materials, and of a supporting element of larger particles all bonded with an adhesive bonding agent. A process for manufacturing the improved rigid filter plate is also set forth.

Abstract: An improved rigid filter plate for sludge dewatering is comprised of a filter element of two or more sizes within the range of 8 to 100 grid of jagged, irregular hard particles of aluminum oxide or similar materials, and of a supporting element of larger particles all bonded with an adhesive bonding agent. The particles in the filtering element increase in average diameter progressing from the upper surface to the lower surface of the element. A process for manufacturing the improved rigid filter plate is also set forth.

Abstract: A bottom for a filter of the type that employs granular material for removing impurities from liquids includes a trough, the bottom wall of which is interrupted by an egress passage for the granular material. Lateral wall sections of the bottom slope upwardly away from the trough toward sidewalls of the filter. An elongate header, having a central passageway therethrough, is embedded in an elongate sidewall section defining a part of the trough, and a plurality of openings are provided through an outer wall of the header and spaced-apart along the elongate extent thereof for permitting filtered liquid to pass into the header. A plurality of conduits extend laterally from the header and include central passageways communicating with the central passageway of the header. These conduits are spaced-apart along the elongate extent of the header and slope upwardly from the header toward sidewalls of the filter and are embedded in the sloping lateral wall sections of the bottom.

Abstract: Biological treating systems include a treating tank for receiving wastewater to be treated, and a wastewater contacting unit mounted for reciprocating movement into and out of wastewater retained within the tank. Movement of the unit out of the wastewater exposes it to oxygen that is needed to maintain an aerobic environment for biolgical slimes, and movement of the unit into the wastewater permits these slimes to feed upon and metabolize pollutants therein. Preferably the systems include a plurality of wastewater contacting units positioned in pairs on opposite sides of axles and connected thereto. These axles are mounted for reciprocating movement, and a drive mechanism is provided to reciprocate the axles and the connected pairs of contacting units.

Abstract: Quick-cooking white, brown, and wild rices are prepared by a process wherein the rice is soaked in water, cooked, and dried in a centrifugal fluidized bed drier while being tumbled at at least two different centrifugal forces.