Abstract: Tube of thermoplastic material, comprising longitudinal channels of rounded cross section and having such wall stresses that, after axially cutting the tube, the edge parts beside the cut edges overlap each other for less than 5% of the outer circumference of the tube.

Abstract: A method and device for cooling molds circulating in a horizontal plane, in which siphon action is used to pass cooling liquid from a top gutter through the molds. In this way the whole cooling system is becoming constructively simplified, such that production speeds can be increased, with the consequent greater length of the cooling system, but without its becoming unduly complicated. This effect is realized irrespective of the nature of the machine or the number of molds.Method and device are especially advantageous when applied with the manufacture of plastics tube, more particularly yet with the manufacture of plastic corrugated tube.

Abstract: A plastic bag provided with a filling valve and a gas permeable dust filtering pocket opposite said valve, allowing gas to escape from the interior of the bag.A disconnectable spot adhesive connection exists between a layer of said pocket and the adjacent bag wall parts opposite a corner flap. An additional adhesive or welding connection may be present near the free end of the pocket for connecting the layer with the bottom flaps.

Abstract: An apparatus for installing a sealing ring in a groove chamber of a socket by impressing said sealing ring comprising a sealing ring impression member and sealing ring retaining means for maintaining the sealing ring in the impressed state said retaining means comprising two axis with flat sides.

Abstract: The invention relates to a pipe part with a socket being provided with longitudinally extending channels. The channels extend into the wall of the socket. The socket engages a J-shaped retaining ring which forms with the socket a recess for retaining the flange of a seal that includes a sealing sleeve. The retaining ring adheres to the outer side of the socket by an adhesive.

Abstract: A plastic pipe comprises an inner wall and an outer wall, being integral with longitudinal partitions betweem them and bounding longitudinally extending channels and a circumferential, helically or non-helically extending groove, which groove has been formed by closing the channels by pressing channel wall parts onto each other. A retaining ring may be snapped into an external groove.

Abstract: Method for connecting thin-walled plastic tubes by heat welding wherein a normal plastic tube is heated and provided with a funnel-shaped widening and another tube is heated and provided with a conical narrowing, the narrowing being pushed into the funnel-shaped widening so that these parts are heatsealed to each other.

Abstract: The raised edge part of a deep-drawn plastic cover is printed by pressing a carrier of a resilient deformable material, carrying a coloring composition, against the raised edge part.An apparatus for manufacturing the plastic cover comprises a deformable carrier for carrying a coloring composition. The carrier is integral with a cylindrical part connected with a first cylinder. Two concentric cylinders, positioned around the first cylinder at either side thereof, deform annular parts of resilient material and press these annular parts against the raised edge part when, on the one hand, the first cylinder and, on the other hand, the two concentric cylinders are moved with respect to each other.The coloring composition may also be carried by a layer-shaped carrier material.

Abstract: A socket of a thermoplastic pipe is provided with an internal groove by subjecting the tube to an upsetting action and simultaneously inflating the tube by an inner pressure. Subsequently a moulding ring is expanded and the tube is shrunk onto the expanded ring by cooling. Before shrinkage the inner diameter of the bottom of the groove is at least equal and preferably greater than the outer diameter of the moulding ring in expanded form.

Abstract: A composition of polyvinylchloride containing the usual additives and a plate out preventing, chemically or physically acting drying agent. The drying agent is preferably an expanded and finely ground aluminiumsilicate, having a high oil absorption and water absorption and preferably low amounts of earth alkaline metals. The plate out preventing drying agent is incorporated in a normal additive composition in order to avoid handling of voluminous masses of drying agent. This incorporation is executed by mixing with a mixture of additives or during the chemical reaction for preparing the additive composition.

Abstract: Plastic pipes comprising an inner and outer wall being interconnected by lengthwise extending connecting partitions, forming channels, the ends of the channels being each separately sealed by sealingly pressing the end walls of a channel to each other after these walls have been heated to a temperature surpassing the plasticizing temperature.

Abstract: A gutter fitting 1 comprises a body member 2 defining a channel for receiving therein a gutter length. A sealing member 6 extends through a slot 8 in the body member and has a respective compressible sealing portion 9 extending transversely of the slot 8 on one or each side of the slot for providing a seal between the inside surface 10 of the body member and the outside surface of a gutter length (not shown) received in the channel. The sealing arrangement is particularly applicable to rectilinear gutter systems.

Abstract: A thermoplastic socket pipe part with a sealing member comprising a sealing head and sealing sleeve, the sealing head being retained by means of a retaining ring, which retaining ring is formed by bending back the end part of an extruded plastic tube provided with three widenings with decreasing inner diameter as seen from the free end of the plastic tube.

Abstract: The present disclosure is directed to a centering device for shaping tools for extrusion presses, wherein an outer mandrel together with an inner mandrel define a through gap for plastic extrusion material which device has a plurality of centering members supported on the outer mandrel which are distributed over the periphery of a radial plane and which are adjustable in the radial direction and which are constructed in the form of push rods guided for radial displacement. Each push rod (6,106) has associated therewith an individually adjustable drive, an adjustable lever (7,107) supported for pivoting on the outer mandrel and which are actuable by means of a tightening device (8,108) and form a transmission gear for applying the tightening force.

Abstract: Method for installing a sealing body in a groove of a socket by forming a closed space in the inner side of the socket. Said closed space is bound by an inner core and an inflatable core being connected with each other by a connecting wall part and is filled with a flowable thermoplastic elastomer through an opening in the wall of the groove. After setting of the thermoplastic elastomer, the two cores are removed.

Abstract: Pipe part with socket being provided with longitudinally extending channels, said channels also extending in the wall of the socket, said socket being provided with an annular groove, formed by sealingly pressing the walls of the channels onto each other, the socket further engaging a J-shaped retaining ring forming with the socket a recess for retaining the flange of a sealing means, comprising a sealing sleeve.

Abstract: Plastic pipes comprising an inner and outer wall being interconnected by lengthwise extending connecting partitions, forming channels, the ends of the channels being each separately sealed by sealingly pressing the end walls of a channel to each other after these walls have been heated to a temperature surpassing the plasticizing temperature.

Abstract: Coloring composition for coloring thermoplastic polymers obtained by solidifying a liquid mixture of coloring pigments and an ester of phtalic acid and an alcohol. The composition contains at least 40% of pigments and at most 60% of an ester of phtalic acid and an alcohol comprising 12 to 16 carbon atoms.

Abstract: A plastic pipe comprises an inner wall and an outer wall, being integral with longitudinal partitions between them and bounding longitudinally extending channels and a circumferential, helically, or non-helically extending groove, which groove has been formed by closing the channels by pressing channel wall parts onto each other. A retaining ring may be snapped into an external groove.

Abstract: Socket pipe of thermoplastics having a groove with longitudinally extending additional recess, which groove is bound by a radially extending head portion.