Abstract: An apparatus for introducing gas into a large body of liquid, including a horizontal frame on ballast adjustable floats, a pressurized gas source, a vertical shaft rotatable about its axis, and a plurality of blades submerged in the liquid and extending radially from a hub on the lower end of the shaft. The blades each have an elastomeric membrane around a longitudinal member, where the longitudinal member is hollow with a closed end and in communication with the pressurized gas source through the shaft on the other end, with openings through its lower side, and the elastomeric membrane has perforations which are spaced from the longitudinal member openings. A drive on the platform rotates the shaft via a ring gear around the shaft with a key connection thereto allowing axial movement therethrough, and an inwardly facing surface supported on bearings. A selectively driven and smaller pinion gear directly engages the ring gear.

Abstract: An assist mechanism for assisting in the pivotal movement of an enclosure member between closed, intermediate, and open positions. A first biasing member has a swing arm pivotally connected to a strut and extends between a base plate and enclosure member, and a second biasing member has a link pivotally connected to a limited tension spring and also extends between the base plate and enclosure member, whereby each impart a substantially biasing force substantially on only one side of the intermediate position, with the first biasing member biasing the enclosure member away from the closed position, and a second biasing member biasing the enclosure member away from the open position.

Abstract: A lift assist mechanism for lifting a large enclosure that is pivotally attached to a body member, between a closed position, an intermediate position, and an open position. The lift assist mechanism includes a swing arm member and an expansible strut member. The swing arm member is pivotally attached to the body member at a first end and to a first end of the strut member at its second end. The second end of strut member is pivotally attached to the enclosure member. The pivot point between the swing arm member and the strut member pushes against a base plate associated with the body member when the enclosure member is in its closed and intermediate positions.