Abstract: A part molded from thermoplastic material is disclosed comprising welding bush portions each of which are provided with a heating coil for connection with tubularly-shaped parts. A clamping portion with slots and screws arranged in flanges facilitates the clamping of wherein the welding bush portion by the screws against the inserted tubularly-shaped part, assuring fixation and retention of the parts prior to and during the welding process.

Abstract: A unidirectional valve includes a generally tubular housing through which fluid can flow substantially in a straight line. The housing has an interior valve seat portion at the inlet end, in the direction of desired flow, and a valve member which is axially movable by the fluid medium. The valve member includes a rigid annular part and a flexible part and is carried by an axially movable guide member to which the rigid part of the valve member is attached The flexible portion consists of a tapered control skirt extending outwardly from the rigid part. Small differences in pressure or flow volume in the reverse direction cause the flexible part to move outwardly against a sliding surface on the interior of the housing, moving the valve member axially toward the valve seating surface in the closed position. Flow in the desired direction causes the skirt to move axially and fold toward the rigid portion. Various embodiments of the valve member and guide arrangements are shown.

Abstract: A stop valve includes a housing formed with a continuous cylindrical bore; a pair of connecting sleeves are disposed one at each end of the housing and are coupled to it by means of coupling nuts. A spherical stopcock coupled to a shaft is positioned in the bore in the housing along with two sealing rings each adjacent to an opposite side of the stopcock, and two insert rings each arranged to push a different one of the sealing rings into contact with the stopcock. The insert rings are insertable into and held within the housing bore by bayonet-like points. A certain amount of axial play is provided between the connecting sleeves and the housing which is adjustable via the coupling units.