Abstract: A multi-bed filtration system includes an upstream filter bed in series with a downstream filter bed of nonbuoyant media. Also included is a system for periodically backwashing the nonbuoyant filter bed. Coagulant-treated water is passed through the upstream filter bed, followed by the downward flow of water through the downstream filter bed. Thereafter, the downward flow of water through the downstream filter bed is periodically interrupted. During these interruptions, a limited amount of water is introduced upwardly through the downstream filter bed by the backwashing system. Such backwashing frees coagulated solids within the bed, causing the solids to move upwardly through the bed. The solids ultimately collect in a zone above the surface of the bed. When normal filtration recommences, water passes through the deck of solids in the zone prior to entering the nonbuoyant filter bed.

Abstract: The invention relates to a novel tubular fitting member formed of a deformable material, such as steel, which may be combined with a helically wrapped wire screen to produce a mechanical seal of a gap formed adjacent the cut-off end portion of the screen when the screen is cut off perpendicular to its supports. Such cutting produces a loose, tapered wire tail which is normally broken off, thereby producing an open gap in the screen which is wider than the width of the slot between the wire wraps. The tubular fitting member has a groove formed in its outer surface closely adjacent to the screen end of the fitting. The groove defines the inner wall of a deformable flange which may be selectively forced toward the screen to close any gap formed adjacent its end during the cut-off operation.

Abstract: Plural pipe-based well screen segments can be assembled more quickly and easily and with no chance of damage to the screen jacket by welding a boss ring to the center pipe of each segment intermediate the upper pipe end and the screen jacket and then using a slip to support the boss ring. The slip is designed to be supported by holes normally present in the master bushing of a rotary drilling table or platform and is of sufficient height that the screen sections can be joined without the operator having to bend over. A pair of relatively light weight, hinged cantilevered plates can be easily lifted to provide clearance for the screen jacket to be lowered through the table and are then moved to their horizontal position just before the boss ring portion of the screen is lowered so as to engage them. A vertical bar on the slip acts as a wrench stop to permit the upper end of the pipe to be held stationary as the succeeding segment of screen is threaded to it.