Plastic pipes, fittings and joints 2007 conference

AMI is pleased to announce the launch of a new international conference, "Plastic Pipes Fittings and Joints", which will be held at the Maritim Hotel in Cologne, Germany, from 10-12 December 2007

AMI is pleased to announce the launch of a new international conference, Plastic Pipes Fittings and Joints, which will be held at the Maritim Hotel in Cologne, Germany, from 10-12 December 2007.

This event will provide a forum to debate the methods for joining pipes, the manufacture of plastic pipe fittings, their materials and joining equipment.

The conference aims to cover a range of current technical and commercial issues facing the industry including selecting the best materials and processing technology for plastic pipe fittings, and key applications and markets.

A fitting for joining pipe sections can be a simple cuff or in a variety of shapes from 90degree elbow joints to branch and tee fittings.

Plastic pipes are joined primarily by welding, bonding or mechanical methods.

Each method has its own advantages and disadvantages.

For example, welding requires specialist equipment and skilled workers.

On the other hand fittings add additional costs and need to be transported and stored.

Solvent cement is used in some applications, for example for joining CPVC pipe systems.

In the belling mechanical method (used for straight pipelines), one end of the extruded pipe is expanded allowing the end of another pipe to be pushed in to form a joint.

A rubber seal is usually added to ensure a leak proof system.

The simplest belling method involves adding extra equipment to the end of an extrusion line.

This does not work in all situations.

For example, high pressure PE pipes tend to have thicker walls which can be difficult and expensive to bell with precision.

In some instances a pipe socket is moulded on the end of the extruded pipe in a secondary processing step such as thermoforming or injection moulding.

Pipe fitting manufacture often involves several steps.

Sometimes sockets are manufactured completely separately, often by injection moulding, followed by a machining step to create a seat for a gasket, and then welded to the pipe.

For example, spinwelders (using friction to generate heat) have been used to attach injection moulded sockets to extruded HDPE corrugated pipe.

Alternatively, gasketed bell and spigot ends can be manufactured into corrugated pipe during production.

Coupling bands can also be used to join this type of pipe.

The bands wrap around the pipe and are secured with plastic ties.

The materials commonly used in plastic pipes and fittings are polyethylene, crosslinked polyethylene (PEX), polypropylene, rigid PVC (uPVC), biaxially oriented PVC (OPVC), chlorinated PVC (CPVC), polybutylene, acrylonitrile-butadiene-styrene (ABS) and glass-reinforced plastic (GRP).

Other materials such as PVDF and polyamide 11 are used in more specialist applications, for example the chemical industry.

The pipe fitting design for chemical transport must take into consideration the fact that mechanical pipe joints often involve other materials in the gasket, a typical example is an SBR gasket in a PVC pipe bell.

Alternative materials include nitrile, EPDM, fluoroelastomers and polychloroprene.

The common commercial welding methods used to join plastic pipes are butt fusion welding, electrofusion welding, infrared welding, bead and crevice free (BCF) welding, and socket fusion welding.

Other techniques include extrusion welding.

Electrofusion involves the use of a sleeve fitting: the pipe ends are pushed into the sleeve and then welded in place.

In butt fusion welding a hot plate is placed between the two pipe ends and, after the material is sufficiently melted, the plate is removed and the pipes are pushed together to form the joint.

Socket fusion welding uses a metal socket mounted on a hot plate to heat the outside of the pipe end while a spigot mounted on the opposite side of the hot plate heats the inside of an injection moulded pipe fitting.

After heating, the pipe is pushed inside the fitting where it welds.

Infrared welding is a more specialised technique, used in applications such as pharmaceutical and chemical industry pipes.

It is similar to butt fusion, but the pipe ends do not touch the hot plate (this reduces the weld beads).

BCF welding is primarily used on PVDF pipes: an inflatable bladder is placed inside the pipe and a metal collar is heated around the joint.

The melted material retains its shape because of the internal and external pressures.

Plastic Pipe Fittings and Joints 2007 provides an international forum for all companies involved in the technology of joining pipes, including pipe industry experts, fitting designers and manufacturers, plastics welding experts and suppliers to the plastic pipe fittings industry.

The deadline for offering a paper is 9th June 2007.

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