Abstract:
A pipe coupling for triple wall corrugated plastic pipe includes a triple wall corrugated bellmouth connector that is of a unitary construction with one end of the corrugated plastic pipe. This bellmouth connector is of higher strength and in cooperation with the two wall corrugated spigot provides a high strength coupling. This coupling includes the bellmouth connector and spigot that are made inline with the corrugated pipe. A method for the manufacture of the pipe includes controlling of an air pressure on the outside of a formed two wall corrugated pipe as an exterior third wall is secured thereto.
Abstract:
Die tooling is formed by forming a series of passages extending in the length of the tooling where each passage has a circumference defined within a body member of the tooling. Preferably the passages are primarily formed using a drilling procedure. The passages define a predetermined pattern of outlets adjacent the extrusion outlet or outlets. The passages between the inlets and outlets can be formed in a series of connected body members with each passage extending through each body member. Die tooling of this design is more robust and cost effective to manufacture.
Abstract:
The pipe molding system includes a separable cooling plug and an automatic procedure to alleviate problems associated with excess plastic continuing to extrude after a sudden shutdown of the extrusion system. The separable cooling plug and shutdown procedure includes accommodating any excess plastic in a created void between the cooling plug and the extruder. This arrangement simplifies removal of the excess plastic and reduces the time required to return the equipment to normal production. Preferably, a controller monitors operating conditions of the system and automatically releases the cooling plug based on the monitored operating conditions.
Abstract:
A ribbed pipe molding apparatus has a die with a plastic flow passage which carries molten plastic from an extruder to a mold for making the ribbed pipe. The plastic flow passage has a downstream flow region which exits at an acute angle through the external surface of the die. The inner wall of the end region which locates downstream of the outer wall of the flow passage in the downstream flow region of the passage has a transition wall part which is also inclined relative to the exterior surface of the die but which is sloped at a angle less than the main part of the downstream flow region of the passage. The transition wall part of the inner wall shapes the mouth of the passage so as to produce a wedging of the plastic flowing through the passage into the mold for extremely efficient production of the ribs on the pipe.
Abstract:
A plastic pipe has a multiple layer wall construction including major and minor wall portions. The major wall portions are formed with first corrugations and are separated from one another by the minor wall portions which are formed with second corrugations and a bowed wall part which is of the same diameter as the first corrugations. The second corrugations are smaller in diameter than both the first corrugations and the bowed wall pipe. The wall construction is cut at the bowed wall part to produce two pipe sections which couple with one another. One of those pipe sections has an open ended bell converted from the bowed wall pipe and the other pipe section has a male spigot formed by the second corrugations of the wall construction.
Abstract:
An extruder for use in a plastic extrusion process comprises a plurality of extruder members. Each extruder member comprises a plate portion and a hollow tubular portion perpendicular to the plate portion. The plate portions of the extruder members are located side by side with one another and define a first plastic handling part of the extruder in which there is firstly a feeding and then a transition of plastic material fed to the extruder. The tubular portions of the extruder members which are telescopically interfitted with one another define a second plastic handling part of the extruder for metering of plastic flow output from the extruder.
Abstract:
A mold block which is used in a moving mold tunnel comprises first and second mold block sections which meet at their parting faces to close the mold block. Each mold block section has a product shaping interior surface and an air movement passage having an entrance at the base of each mold block section, a first opening to the interior surface and a second opening to the parting face of each mold block section. An air flow controller is provided between the parting face opening and the interior surface opening of the passage in the first mold block section and an air flow controller is provided between the entrance and the interior surface opening in the passage in the second mold block section. Through various different positionings of the two air flow controllers, the mold block can be operated in any one of four different modes including a first vacuum forming mode in which air is withdrawn from the mold block through both of the mold block sections, a second vacuum forming mode in which air is withdrawn from the mold block through only one of the mold block sections, a third cooling mode in which air is introduced into the mold block through one of the mold block sections and is then withdrawn from the other of the mold block sections and a fourth blow molding mode in which pressure within the mold block is released through both mold block sections.
Abstract:
A pipe cutting apparatus comprises a housing with a pipe passage through the housing, a rotatable collar and a rotatable ring both of which rotate about the pipe passage and a pipe cutter mounted on the collar. The pipe cutter is movable inwardly toward and outwardly away from the pipe passage and has a drive gear which engages the ring such that differences in rotating speeds between the collar and the ring operate the drive gear to produce movement of the pipe cutter.
Abstract:
A travelling mold has mold blocks formed by opposing mold block sections which open and close relative to one another. The mold sections travel horizontally around a continuous track which is fitted with a plurality of side-by-side mold block carriers on which the mold block sections are releasably supported. The mold block carriers are provided with carrier gears which engage with the main drive gear of the mold so that the mold is driven by engagement of the drive gear with the carriers and not the mold block sections.
Abstract:
A travelling mold tunnel for the vacuum forming of profiled tube from extruded parison of molten thermoplastic material includes a plurality of parallel mold cavities with a vacuum applied to each of the mold cavities.