Abstract: A container cover comprises a central dome, a peripheral rim portion surrounding the central dome, wherein the central dome extends upwardly from the peripheral rim portion, a skirt extending downwardly from an outer edge of the peripheral rim portion, and a plurality of grippers. Each gripper comprises a flange extending downwardly from a lower surface of the peripheral rim portion and at least two gripping fingers extending downwardly from the flange. The skirt and the grippers form a space for receiving an edge protrusion, for example a curled edge, of a container body. Each of the at least two fingers has a protrusion extending toward the skirt and the fingers are adapted to provide a gripping force to an edge protrusion of a container received in the space. The plurality of grippers are spaced from one another around the peripheral rim portion. The container cover may be combined with a container body having an edge protrusion at its opening.

Abstract: A composite container comprises lateral walls composed of laminar composite material sealed along at least one seam to produce a cylindrical or polyhedral body, a conical top member composed of plastic material joined to the lateral walls by adhesive means, and a bottom member of any suitable construction. Particular embodiments include containers for toxic chemical snad petroleum products.

Abstract: The invention comprises a screening device for separating fine particles from a stream of air and a particulate mixture containing coarse and fines which includes a box-like hollow housing tilted downwardly at an acute angle. The housing contains a plurality of elongated screening elements and an air cleaning device consisting of a blowpipe and a series of nozzles directed at the screening elements through Venturi tubes. At periodic intervals a jet or pulse of air is injected into the Venturi tubes to reverse air flow and rid the screen elements of adhered coarse particles. Substantially complete fines removal can be achieved by employing a recycling loop between the coarse particle outlet and inlet of the housing.

Abstract: The size of an air filter is greatly reduced compared to the size of conventional bag house type filters by the use of pleated paper filter elements grossly derated to withstand the sudden pulsating forces inherent in reverse jet cleaning.