Certain embodiments include a screen assembly of a vessel, where the screen assembly includes a plurality of fixed elements and a retainer, and the retainer includes a ring, a plurality of wedges disposed about the ring, and a plurality of keyholes at spaced locations about the ring. Each keyhole includes a bore and a slot extending from the bore into an adjacent wedge of the plurality of wedges, the slots have a width less than the bores, and the retainer may receive the fixed elements through the bores and may be rotated in a relation with the plurality of fixed elements to bring the plurality of fixed elements into simultaneous engagement with the wedges.

Certain embodiments include a screen assembly of a vessel, where the screen assembly includes a plurality of fixed elements and a retainer, and the retainer includes a ring, a plurality of wedges disposed about the ring, and a plurality of keyholes at spaced locations about the ring. Each keyhole includes a bore and a slot extending from the bore into an adjacent wedge of the plurality of wedges, the slots have a width less than the bores, and the retainer may receive the fixed elements through the bores and may be rotated in a relation with the plurality of fixed elements to bring the plurality of fixed elements into simultaneous engagement with the wedges.

A gas lift conveyance device moves a slurry through an upwardly extending lifting section of a conduit in communication from a source location at a first pressure to a discharge location at a lesser second pressure. A gas injector of the device injects gas into the conduit through a variable position valve that is controlled by a controller that uses a representative value measured by a sensor as input to a closed loop control algorithm of the controller. The representative value may be a pressure or flow rate that is representative of the gas delivery rate. The device provides: (i) automated control over the delivery rate of slurries; (ii) real time values of air rate, valve position, and pressure; (iii) a reduction of energy input due to optimal use of air; and (iv) a reduction in air pumps stalling or plugging failures.

The disclosed invention pertains to a novel device and method for effectively emptying water treatment vessels. This innovation may provide a sturdy, aluminum-framed apparatus featuring a cradle and adjustable legs. The water treatment vessel may be securely fastened onto the cradle after the frame is first adjusted to a suitable height using the device's adjustable legs. A water hose may be attached to the device's fitting, directing water into the vessel for rinsing filter media or resin. The inverted vessel's contents may flow onto a washout tray for collection. This innovative device may enhance stability, ease of use, and safety, making it ideal for emptying water treatment tanks or vessels of varying shapes and sizes.