Abstract: Pipe closure device with opposing dual mandrels has external conical surfaces which cooperate with internal conical surfaces of segmented rigid wall engagement member. Rotation of threaded shaft causes relative axial movement of dual mandrels and effects outward radial motion of rigid wall engagement members and outward motion of elastomeric seal, securing device to wall of pipe and sealing pipe closed. Rotation of shaft in opposite direction releases elastomeric seal and rigid wall engagement members from pipe wall. Inflatable seal seals against inside wall of pipe when inflated. Shaft is rotated by air-powered motor which is insertable and attachable into sealed receiver without use of tools.

Abstract: Normally closed valve for controlling flow of fluid material through a straight, non-tapered conduit has resilient elastomeric seal attached to the perimeters of two axially aligned rigid end plates. Elasticity of elastomeric seal draws end plates together while radially expanding so as to engage and seal against the inner wall of conduit. Valve may be opened by axially separating the two opposing end plates using a locally actuated displacer mechanism attached to one of the end plates, causing the elastomeric seal to radially contract and the valve to open.