Other

Corma, Inc.

Lupke, Manfred A. A.

Lupke, Stefan A.

Manfred A A Lupke

Stefan A Lupke

Mold blocks of a pipe molding corrugator are provided with enhanced cooling capability due to the provision of cooling fins on the side portions of each mold block. Air can be forced between the fins and some exhaustion of the air can occur at the base of the fins adjacent the mold block cavity. With this arrangement, enhanced cooling of mold blocks is possible.

Finned mold block

A pipe connection used in corrugated pipe includes a male/female connection that is configured to accommodate movement of the male connector in the female connector after installation of the pipe. The ability to maintain a satisfactory pipe connection throughout a desired and designed range of movement is helpful in applications where the pipe may be exposed to changing conditions such as ground settling, ground shifting, earthquake or other conditions. The male connector and the female connector for receiving the male connector are oversized to allow additional insertion of the male connector or partial withdrawal of the male connector while maintaining the pipe connection throughout the range of movement. The pipe connection can also be used to provide an effective two stage male/female connection between reinforced plastic pipe sections.

Pipe coupling

In the manufacture of double-walled corrugated extruded pipe it is desirable to form an integral connecting cuff that is of a single wall thickness and typically of a large diameter. The mold blocks and process parameters for forming of the cuff as part of an otherwise double-walled pipe requires a transition as the cuff moves past the die outlets. The present invention allows for accurate sensing and control of air pressure and temperature as the cuff moves past the die outlets. Improvements in both the die tooling and the method of manufacture are disclosed.

Air pressure control for corrugator

The present invention provides a spider for a die head and die tooling that utilizes curved flow guides to direct the flow of plastic through the die head and die tooling. The spider leg splits the stream of plastic flowing through the spider into two independent streams at the upstream end. The downstream end comprises two curved flow guides that are configured to direct the two streams of plastic towards a longitudinal center plane of the spider leg. The turbulence caused by the curved flow guides creates obtuse or acute angled welding lines between the two streams of plastic. These obtuse and acute angled welding lines provide stronger bonds than the known spider legs that create butt welding or right angled welding lines.

Die head and die tooling spider with spider legs having curved flow guides

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.

Method for forming inline triple wall coupling connector

Pipe corrugators having opposed series of pushed mold blocks forming a moving mold tunnel are subject to significant thermal expansion and are designed with a thermal expansion gap. The present invention provides a method and apparatus for measuring changes in this expansion gap and preferably recognizing potential thermal issues before serious problems occur. A sensor is provided adjacent a mold block drive that preferably detects a time duration between sensing a trailing portion of a lead mold block and a leading edge of a following mold block separated from the lead mold block by the thermal expansion gap. This time duration in combination with a speed of the pushed mold blocks is used to calculate the size of the thermal expansion gap.

System and method for identifying thermal expansion issues in a corrugator

A two stage mold block transfer station is used the exit of a moving mold tunnel to quickly move mold blocks to a clear position relative to the molded product. Once in the clear position the mold block is rotated and provided to a return drive moving the mold block back to the inlet of the moving mold tunnel. By moving the last mold block of the moving mold tunnel primarily away from the longitudinal axis of the mold tunnel less mold blocks are required. Various arrangements for moving of the mold blocks can be used achieve this advantage.

Mold block return

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.

Die tooling for extruding tubular product

A corrugated pipe having a non circular in cross section profile and at least one generally elongate wall section is improved by using a variable height corrugation in the length of the elongate wall segment. The variable height corrugation is of a greatest height at a center portion thereof and decreases in height towards the end points of the elongate wall segment. A spanning type truss arrangement is formed that opposes inward deflection of the straight wall segment.

Non-circular pipe profile

A molding apparatus for the manufacture of pipe advantageously uses a cooling plug that is adjustably-secured to the extrusion head to compensate for misalignment of the extrusion head relative to recirculating mold blocks. This provides a simplified adjustment for adjusting the molding apparatus to correct for wall thickness variations in the molded pipe. This apparatus can be used in combination with existing alignment systems.

Alignable cooling plug for extruder

A piece of corrugated pipe cut from a longer length of pipe is provided with a pipe coupling part by subjecting one or more of the corrugation crests on the pipe to heat and pressure. This reshapes the one or more corrugations to form a seal receiving recessed spigot on the piece of pipe.

Method of forming corrugated pipe with a pipe spigot seal seat

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.

Pipe extruding system with cooling plug separation

In at least one method for manufacturing a double-walled, thermoplastic tube with a connecting sleeve, which enables precise and complete moulding of the connecting sleeve by simple means, it is provided that a) a first tube () is extruded into a mould tunnel () comprising at least one row of moulds () guided on a path, b) the first tube () is given a corrugated shape in at least one first section and expanded into a connecting sleeve in at least one second section, c) a second tube () is extruded into the first tube and pressed against the corrugation troughs () of the first tube (), d) while the first tube () is being given a corrugated shape and the second tube () extruded into the first, the space (A) between the two tubes () is subjected to a pressure p1 that is above atmospheric pressure, e) the space (A) between the two tubes () is subjected, at a specified time before or after expansion of the first tube () into a connecting sleeve, to an essentially constant pressure p&#x2266;pabove atmospheric pressure, or to a variable, but not continuously declining pressure pf) during extrusion of the second tube () into the first tube (), which has already been expanded into a connecting sleeve, the second tube () is internally subjected to a pressure pabove atmospheric pressure and pressed against the first tube (), and g) pressure pis subsequently again applied to space (A) between the two tubes.

Method and device for manufacturing a double-walled, thermoplastic tube with a connecting sleeve

In a method for manufacturing a double-walled, thermoplastic tube with a connecting sleeve, which enables precise and complete molding of the connecting sleeve by simple means, it is provided that a) a first tube () is extruded into a mold tunnel () comprising at least one row of molds () guided on a path, b) the first tube () is given a corrugated shape in at least one first section and expanded into a connecting sleeve in at least one second section, c) a second tube () is extruded into the first tube and pressed against the corrugation troughs () of the first tube (), d) while the first tube () is being given a corrugated shape and the second tube () extruded into the first, the space (A) between the two tubes () is subjected to a pressure pthat is above atmospheric pressure, e) the space (A) between the two tubes () is subjected, at a specified time before or after expansion of the first tube () into a connecting sleeve, to an essentially constant pressure p&#x2266;pabove atmospheric pressure, or to a variable, but not continuously declining pressure p, f) during extrusion of the second tube () into the first tube (), which has already been expanded into a connecting sleeve, the second tube () is internally subjected to a pressure pabove atmospheric pressure and pressed against the first tube (), and g) pressure pis subsequently again applied to space (A) between the two tubes.

Device for manufacturing a double-walled, thermoplastic tube with a connecting sleeve

A pipe mold () produces plastic pipe with an internal wall having a first wall portion () and a second wall portion (). The pipe mold () includes a two stage cooling plug () to assist in setting the pipe wall. The first cooling stage () is controlled to remove heat from the pipe wall to partially set the plastic without excessive cooling. The partially set plastic pipe then passes over a second stage () where less precision in the cooling of the pipe occurs. The partially set plastic is more tolerant and subject to less damage. Preferably both the first and second stages () include separate temperature sensors () and control arrangements () for varying the cooling medium of each stage. In a preferred embodiment a cooling medium is circulated through a first stage at a temperature and at a flow rate to maintain the first stage () within a narrow temperature range about the temperature of the cooling medium. The staged cooling plug () allows better control at initial startups and with varying operating conditions.

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Thornhill, Canada

Manfred A A Lupke