Page 256 - Pipeline Pigging Technology

Specialist pigging techniques

SPECIALIST PIGGING TECHNIQUES

INTRODUCTION

Whilst the majority of operational pipelines can be successfully pigged
using standard proprietary products, there are occasions where a specialist
"one-off type of pig is required. Due to the individual nature of such pigs, it
is usually not reasonable to expect the manufacturers of standard pigs to
produce them, and in any case they often do not have the necessary
operational experience to design such a specialist pig.
In 1979 McAlpine Kershaw was established for the specific purpose of
designing and producing specialist pigs to cope with unusual and difficult
circumstances. Our initial thoughts were to produce a range of various
specialist pigs, but we quickly learnt that it was better to wait for a pipeline
operator to approach us with a specific problem and then to design and
develop a pig to solve the problem.
During the 11 years of our existence we have designed and developed
many specialist pigs to solve specific problems, which are described in this
paper.

SPECIALIST PIGS

Multi-diameter pig

This was the first development project which we undertook on behalf of
a client in the Middle East, who required to clean a water-injection ring main
having diameters of pipe ranging from 20in to 26in. At the time this project
was undertaken, there were no other suitable multi-diameter pigs on the
market. Our own multi-diameter pig is based on a different principle of
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