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The cylinder guard, made from AKROMID® A3 S1 Grey (4377)

AKROMID® A3 S1 Changing of the Guard

Technical Moulder Glazpart Ltd (Banbury, UK) in conjunction with its major customer have “pushed the boundaries” and developed an innovative plastic cylinder guard for a new mainstream cylinder valve.

“Super tough” AKROMID® A3 S1 grey, thanks to its outstanding impact properties, has successfully replaced a steel valve protection guard. At 100 kg in weight, this is an extremely demanding application, and AKROMID® A3 S1 grey has fulfilled the 1.2 metre drop test at temperatures between -40° C and +65° C. A third party certification body has tested and certified the guards for use under these conditions.

K.D. Feddersen UK Ltd. closely supported Glazpart through the material selection and trialling stages until approval.

A program to identify a material that could replace steel for a new large industrial oxygen cylinder guard was started at Glazpart in April 2011. AKROMID® B3 S1 grey (4377) was developed and submitted for tests along with a competitive product (default high impact material).

Argumentation AKROMID® B3 S1 grey versus competitive product prepared by the distributor for submission to the OEM. Due to the demanding drop impact tests (100 kg cylinder raised 1.2 metres and dropped on the guard onto a hard surface) at -40° C to +65° C, the guards broke.

Modifications to the tool were made to locally thicken the area where the breakage occurred. Further drop testing showed that passes were borderline, and so additional tool modifications were carried out.

Moulding trials were supported by Martyn Jocelyn, Sales Manager at K.D. Feddersen UK Ltd., and later by Jürgen Ulrich, Application Engineer at AKRO-PLASTIC.

In September 2012, the latest AKROMID® A3 S1 grey (4377) and not guards made from the competitive product were submitted to the Belgian certification body Apragaz in Brussels. AKROMID® A3 S1 grey (4377) passed all tests required for cylinders up to 100 kg gross weight at temperatures -40° C to +65° C.

In September 2012, the first order was placed, and AKROMID® is the only approved material for this application to date.

AKROMID® A3 S1 is a highly impact-modified PA 6.6 with very good processing characteristics. The material is produced at AKRO-PLASTIC’s state-of-the-art compounding operation in Niederzissen, Germany.

»It is easy to get a guard for a 50 kg cylinder, but there has never been one for a 100 kg one«

a spokesman for the OEM

The new guard has taken 2 years and numerous iterations to perfect. The current steel guard is sourced from China; they are shipped to the UK in large batches for test shop workers to clamp onto cylinders. However, with around 300 cylinders tested every shift, lead times that sometimes stretched to six months and occasional quality problems, it has been difficult for test shops to keep up. This was the driving force to contact Glazpart, the Oxfordshire company that manufactures the plastic guards used on small cylinders.

»Across the UK, we buy about 30,000 guards a year, and that figure is growing” [...] “The shortages we used to get are a thing of the past now,«

the spokesman continued.

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