Abstract: The invention refers to a method and apparatus for manufacturing a single-wall pipe, tube or like conduit (9,44) having smooth inner surfaces and a mechanical-strength enhancing pattern of walls, flanges or ridges on the outer surface thereof, the conduit being made of plastics or like extrudable material.

Abstract: A reformable, shape retentive hose having a precured tube located in a hose sidewall, and a reformable rod inserted in the precured tube. A method for making hose by placing at least one precured tube in the sidewall of a hose during the time that the hose sidewall is formed, curing the hose assembly with the precured tube in the sidewall, and inserting a reformable rod in a portion of the precured tube.

Abstract: A heat shrinkable tubing is described which has a texturized surface. Upon applying the heat shrinkable tubing to a complex shaped object and applying heat the tubing shrinks radially and linearly, uniformly so as to preserve the texturized friction surface, shrinking over depressions and expansions of the complex surface without wrinkling.

Abstract: A method of making blow-molded perforated tubing and the tubing made by said method is provided. In the method of the invention, hollow-walled protuberances are blow molded into the side of the tubing as the tubing is formed and perforations are formed by cutting the hollow-walled protuberances.

Abstract: Extruded web multiple panels are produced with undulated webs by extrusion of a thermoplastic material by a device including an extruder, a slotted die connected thereto which comprises core pieces in the die slot for forming the webs, a movable mold channel placed downstream of the slotted die, and a removal device. The undulation of the webs is produced by friction forces rhythmically alternating in direction crosswise to the extrusion direction. The friction forces are allowed to act in the mold channel on the extrudate in an area where it is still above its softening temperature. The friction forces are produced either by a rhythmic crosswise movement of the entire mold channel or by movable sections of the mold channel walls of a special mold channel.

Abstract: In an apparatus such as a corrugator for manufacturing thermoplastic pipe with a corrugated outer wall and a smooth inner wall, a calibrator is employed to provide a smoother inner wall and a more rapid inner wall cooling. The calibrator includes a tube wound into a helical coil and an adjustment mechanism for adjusting the coil diameter. A cooling fluid may be passed through the tube.

Abstract: Method and apparatus for molding of plastic tubing, including an elongate nozzle receiving an extrudate of an expandible plastic material under pressure from an extrusion head and a coaxial mandrel with air supply and evacuating passages communicating with a vortex generation tube for cooling air before its introduction to the interior of the formed tubing for its blowing and conforming to the walls of a tubular mold cavity formed by a series of forwardly moving molds.

Abstract: Relatively long plastic microfilaments are used to make reinforcing, filler materials and fabrics. A blowing gas is applied at a positive pressure to the inert surface of a liquid plastic film formed across a coaxial blowing nozzle to blow the film and form an elongated hollow tube having a thinned wall or weakened portion. An entraining fluid is directed at an angle over and around the blowing nozzle and as it passes over and around the blowing nozzle, it dynamically induces a pulsating or fluctuating pressure field at the opposite side of the blowing nozzle in the wake thereof and produces a laminar flow of entraining fluid in the vicinity of the forming elongated tube.

Abstract: Double walled thermoplastic tubes, with corrugated outer walls and smooth inner wall are formed with integral bell sections spaced along the tube. The outer, corrugated wall is formed with a bell section. One of the walls is pierced between the ends of the bell section to allow the escape of air, and the inner wall is pressed outwards into engagement with the bell section of the outer wall.

Abstract: A plurality of internal couplers (A, B, C, D) are integrally connected end to end in a single tubing construction of indeterminant length. Between each coupler is an annular, frangible region (14, 24) of thin plastic. In the field, the individual couplers are readily broken manually from the tubing construction. Each coupler includes a plurality of cleats (40) which are partially surrounded by a region (50) of relatively thin plastic material. The couplers are manufactured by continuously blow molding a sleeve of softened plastic into the tubing construction of indeterminent length.

Abstract: An apparatus for the production of plastic pipes with transverse grooves comprising half shells each having a mold recess which are arranged on a machine bed driven in a cycle. The half shells are assembled in pairs in a molding path to form a complete mold, the injection head of an extruder being arranged at the beginning of the molding path. Furthermore, the half shells are provided with vacuum channels, each vacuum channel being connected to a respective mold recess. The vacuum channels are joined into vacuum connections formed in the machine bed, and the half shells are provided with cooling channels which join into cooling water inlets and outlets in the machine bed. In order to ensure an exact setting of the half shells during the molding operation, the cooling channels, on the one hand, and the vacuum channels on the other hand, in a given half shell are completely separated from each other.

Abstract: A fluid distribution device particularly useful as a drip irrigation emitter, comprises: a continuous plastic tube for conveying the fluid therethrough; and a plurality of individual plastic sleeves enclosing and fixed to the tube at longitudinally-spaced sections along the length of the tube; each of the sleeves being deformed to define a pressure-dropping fluid passageway between its inner surface and the outer surface of the section of the tube enclosed thereby; each of said tube sections having an inlet opening through the tube wall leading to the interior of the tube, and an outlet leading externally of the plastic sleeve.

Abstract: Apparatus for making profiled plastic tube and comprising two circulating endless chains, each making a plurality of mold halves move along with a tube coming from an extruder, these mold halves pairwise constituting a mold cavity in which the tube is being given its profile. According to the invention the molds are movable relative to the chain links in a direction perpendicular to the direction of movement of the links. The machine frame is provided with guides for the mold halves, some located interiorly, others exteriorly, with respect to the chain loop, such that once closed, the cavity formed by the pairs of mold halves will remain closed and undisturbed up to the end.Preferably the transitions between curved portions and the operative portion of the path of the mold halves at the entrance and the exit ends are bending points of mathematically calculated paths and the operative straight path tangentially joins said transitional portions.

Abstract: A process for the manufacture of a flat-shaped hollow body through the use of a forming die, wherein mold segment halves move continuously along a forming die and which, upon entering the forming die, are moved in an operating direction facing each other in pairs in a closed mold in tight proximity to each other. The mold is injected with warm thermoplastic hose stock which is shaped under vacuum action in the mold. In order to produce flat-shaped hollow bodies on a continuous basis the hose stock is subjected to vacuum action over at least a portion of its cross section even before mold segment halves are brought together and is pressed together accompanied by the formation of welds and the creation of hollow spaces over a portion of its cross section.

Abstract: The specification discloses an apparatus and method for concurrently manufacturing at least two semiround tubing structures. An extruder including plasticizing means for a plurality of plastic resins extrudes semiround and linear strips of plastic material in generally two back to back D-shaped sleeves. Between the D-shaped sleeves, a strip of adhesively non-compatible material is extruded so that the D-shaped sleeves may be separated. The rounded portions of the D-shaped sleeves are molded in a continuous blow molding arrangement to form the top wall of the semiround tubing. The tubing is cooled, and the two semiround tubing lengths separated from the adhesively non-compatible strip inbetween. Optionally, the base of the semiround tubing may be perforated. The two lengths of semiround tubing are folded with the base inside the top wall and coiled into large reels.

Abstract: Apparatus for continuous extrusion of tubular sections of thermoplastic material having a smooth inner surface and an annularly finned outer surface defined by alternating ribs and grooves. The apparatus comprises a die assembly made up of an outer die part and an inner die plunger. Two sets of chills define in combination a casting cavity having alternating grooves and ribs both having circular cross sections. The radius of the cross section of the grooves is smaller than that of the ribs, preferably the radius of the ribs ranges between 1.25-1.35 times greater than the radius of the grooves. For their displacement along closed loop paths the chills are provided with racks and their back sides are in meshing engagement with gears. A smoothing mandrel is provided in line with the die plunger and is cooled by a cooling fluid.

Abstract: In an apparatus for producing thermoplastic tubing, the apparatus being of the type comprising a pair of complementary mold assemblies providing recirculating mold units which cooperate in pairs along a forward run to define a mold cavity, each mold unit comprises a transversely displaceable die member providing a plurality of half molds which can be selectively displaced to an operative position. The apparatus includes selectively operable cam means positioned along the return runs of the mold units for selectively engaging the die members. The half molds in each die member are configured differently, there being at least one with a smooth inner surface and at least one with a corrugated inner surface.

Abstract: Apparatus for producing corrugated thermoplastic tubing of the type comprising a pair of complementary upper and lower mold assemblies each having an endless chain of articulately interconnected mold blocks which are driven along a forward run and back along a return run, the mold blocks cooperating in pairs along the forward run to form an axially extending tubular mold tunnel, within which the tubing is expanded by vacuum forming or blow molding. The mold blocks have mold-defining faces of corrugated form with alternating troughs and crests. Each mold block is formed with passages which extend between the bases of the troughs of the corrugations and the exterior of the mold block. These passages communicate with the base of each trough throughout its length, and serve to permit the escape of any atmospheric air which is trapped by the tubing in the troughs during expansion of the tubing.

Abstract: A hose construction and apparatus for and method of making such hose construction are provided wherein the hose construction comprises a corrugated outer tube made of polymeric material and having alternating projections and recesses with the recesses having inwardly facing convex surfaces and an inner tube made primarily of polymeric material and having smooth inside and outside surfaces with the outside surface being bonded against the convex surfaces and wherein the inner tube has at least one longitudinally extending polymeric portion comprising same which has electrically conductive particles embedded therein in which the polymeric portion serves as a matrix for the particles and with the polymeric portion being heat fused to the convex surfaces.

Abstract: Apparatus and method for producing thermoplastic corrugated tubing having substantially uniform thickness throughout comprises extruder and step of forming hollow smooth-walled extrudate. Corrugating structure immediately adjacent extruder is arranged to receive extrudate and to form corrugations therein. Such structure includes continuously moving cooperating mold blocks configured to form alternating annular peak portions, valley portions and interconnecting side wall portions in extrudate when it is blown into intimate engagement with configured mold blocks. Thickness of extrudate being corrugated is controlled to provide relatively thin extrudate portions during formation of annular valley portions and relatively thick extrudate portions during formation of annular peak and interconnecting side wall portions.

Abstract: An apparatus for producing multi-walled thermoplastic tubing having a corrugated wall and a substantially smooth inner wall secured to the corrugated wall, there is incorporated two sets of endless flexible belts each of which is entrained around rotatable end rolls, the outer runs of the belts of one of the sets thereof alternating with the outer runs of the other of the sets thereof, with these outer runs of the various belts serving to urge the inner wall against the corrugations of the corrugated wall while the thermoplastic material of the walls is soft thereby to secure the walls together, and with an electrically energizeable heating coil being provided for softening the thermoplastic material of the corrugated wall to ensure satisfactory securement between the walls.

Abstract: An apparatus for the manufacture of transversely contoured tubing from thermoplastic material. The tube emerges in the plastic state from an extrusion nozzle and is guided into a mold composed of a plurality of mold sections in series, with inner side working surfaces forming the transverse contours. Each of the mold sections is composed of two mold halves which are arrayed along a straight molding run in two confronting rows and which are circulated. In the circulation, the first two mold halves are moved apart and out of the molding run at the end of the molding run and are guided to a return run on which they are separately returned to the beginning of the molding run where they are rejoined to the preceding mold half. The mold halves are guided on the return run in a continuous, accelerated and then decelerated movement by a transfer mechanism which couples and uncouples from the mold halves as actuated by pneumatic cylinders under the control of limit switches.

Abstract: Machine for imprinting indicia on thermoplastic corrugated tubing comprises framework with structure connected thereto for guiding tubing along predetermined path of travel. Motivator on framework moves tubing along its path of travel, and imprinting structure mounted adjacent path of travel of tubing functions to selectively move into and out of engagement with exterior surface of tubing. Imprinting structure includes print wheel with spaced apart teeth at periphery thereof arranged to mesh with corrugated tubing when imprinting structure is in engagement therewith. Conductive print type are releasably secured to print wheel at periphery thereof, and heater cartridges function to heat print type. Print wheel is selectively shifted into engagement with exterior surface of corrugated tubing as it moves along its path of travel so that heated print type softens thermoplastic to thereby heat stamp indicia of type onto corrugated tubing.

Abstract: In order, in the molding of corrugated thermoplastic tubing, to overcome the disadvantage that pressurized air which is supplied to a zone within the tube of thermoplastic material as it is extruded from an extrusion head into the entrance of a tubular mold tunnel may tend to cause rupturing of the tube at the area immediately adjacent to the extrusion head where the tube is unsupported by the wall of the tubular mold tunnel the pressurized gas is supplied at a low pressure to a first zone within the tube of thermoplastic material to support the tube against the wall of the tunnel, and pressurized gas at a higher pressure is supplied to a second zone within the tube to urge the tube outwardly into the corrugations of the tubular mold tunnel. A first sealing arrangement separates the first zone from the second zone which is disposed downstream of the first zone, and a second sealing arrangement defines the downstream end of the second zone.

Abstract: A molded rubber article is described having an exterior or surface layer which is formed of a blend including a heat setting rubbery polymer, and a halogenated polyethylene acting as an internal mold release agent during processing and also enhancing the surface qualities of the molded article.

Abstract: In a process for forming a resin body, the thickness of the body is altered by altering the feed rate of raw material to an extruder and the screw rate of the extruder screw in such a relationship to alter the quantity extrusion rate without altering the amount of resin within the extruder.