Abstract: An extruder barrel for twin screw extruders. The barrel body has a removable insert firmly seated in an insert receiving opening extending centrally and longitudinally therethrough. The insert has two circular bores with parallel axes extending centrally and longitudinally therethrough, the bores being in communication along a common chord. The walls of the bores have a wear and corrosion resistant layer that is a powder metallurgical material that is preferably applied by hot isotactic pressing. The preferred powder metallurgical material forming the wear resistant layer is a composition containing at least 50% by weight tungsten carbide with the remainder being nickel. The outer surface of the insert has a thin layer of a heat conductive, malleable material, such as copper, adhered thereto.

Abstract: A method of making metal hydroxide plate blanks for use in an electrochemical cell which includes compressing a porous metal web in at least one compression zone to a substantially non-porous state, attaching at least one a non-porous strip of the same metal to the porous metal web in the area of the compression zone, impregnating the porous metal web with a coating of electrochemically active material to form an impregnated web, removing excess coating from the impregnated web, drying the impregnated web, and dividing the dried web into plate blanks in the area of the metal strip. The metal is selected from the group consisting of nickel, silver and copper, with the preferred metal being nickel.

Abstract: A method of enveloping and assembling positive and negative plates into a group suitable for use in an electrochemical cell by forming at least one row of alternating positive and negative plates of a predetermined number with the top edges of said plates in longitudinal alignment, enveloping the plates with a separator material by bringing a continuous sheet of separator material into contact with both planar faces of the plates and sealing the separator material along the side and bottom edges of the plates to thereby form a row of enveloped plates interconnected to each other by the separator material, assembling the interconnected row of enveloped plates into a folded group by folding the row in an accordion-like manner, and compressing the folded group into a cube of predetermined size. The product of this method is a group of plates located in interconnected pockets of separator material that has been folded in an accordion-like manner and compressed into a cube of predetermined size.