Profiles provide elegant jig solution

Edited by the Engineeringtalk editorial team Aug 10, 2004

A massive pipe measurement gauge built for China's foremost extruder of mains drains and sewers is based on curved structural profiles supplied by MK Profile Systems of Preston.

A massive pipe measurement gauge built for China's foremost extruder of mains drains and sewers is based on curved structural profiles, supplied by MK Profile Systems of Preston to the gauge builder Betalasermike in High Wycombe.

When Betalasermike won the order the design team worked out some initial ideas, most of which were heavily reliant on custom-built parts.

Realising that this would prove prohibitively expensive the company looked around for other possibilities and contacted several profile suppliers, recalls Mike O'Connor of Betalasermike.

The solution suggested by MK involved precision bending 100 x 50mm profiles into exact curves, and this seemed the best way to meet the design requirements.

With the concept agreed MK began work on the detailed design.

"We offer a free design service to all our customers", says Tom Murphy.

"Our main tool for this is 3D AutoCAD which shows very clearly what we are proposing, which is advantageous because of the innovative nature of our solutions".

"Many engineers automatically expect welded steel but realise the advantages of extruded aluminium profiles once they see the CAD drawings".

Profiles can be equivalent to steel in strength, yet are lighter.

The fact that they do not need welding takes significant cost out of construction, and makes future reconfiguration a much more viable prospect.

Total resistance to corrosion is another winner for end users, especially for outdoor and harsh environment applications and in cases like Betalasermike where water is very much in evidence.

The pipes being made in China made are mainly 1.6m outer diameter, although there is some production of smaller sizes down to 700mm, and the wall thickness is 60mm.

They are extruded from a special polymer that will withstand being buried underground for decades and carrying very aggressive media.

"The pipes are extruded very slowly, millimetres per minute and the wall thickness is monitored to clearly defined tolerances".

"Too thin and the long term performance may be compromised; too thick and large amounts of expensive polymer are quickly wasted", explains O'Connor.

Betalasermike's gauge basically measures pipe wall thickness after the extruder.

The pipe passes through two rings made in curved profiles, which support 16 ultrasonic transducers, each monitoring the wall thickness at equally spaced points around the diameter.

The transducers are mounted onto a movable arm driven by a simple chain mechanism so that they can be brought into close proximity to the pipe's outer surface and precisely positioned relative to its centreline.

The levers also carry nozzles so that the pipe's outer surface can be constantly flooded with water to provide a medium to carry the ultrasonic signals.

Water flow management and disposal are also built into the gauge; with so much water about MK provided many galvanised and stainless parts for the jig.

Positioning such a large gauge at the output of the extruder will need fine adjustment for height and side to side.

MK not only understood this but also was able to provide a solution from its standard catalogue parts.

It incorporated small adjustment mechanisms into each leg of the main support, so that once the jig is roughly positioned it can be raised or lowered and laterally aligned.

The gauge has been completed in High Wycombe and shipped half way around the world to it workplace, where it is expected to provide many years of service.