TRAPPED KEYS
February 1st 2004

The ability of Allen-Bradley Guardmasters Prosafe range of trapped key interlocks to simplify safety provision, while at the same time, providing safer access into the largest of machine installations has been demonstrated at Spooners Vicars on Merseyside. The stainless steel Prosafe units are being used to ensure that 32 separate doors on a 90m long triple hybrid continuous bakery oven are securely interlocked and isolated before personnel access is allowed.

Hybrid ovens are typically long pieces of equipment. They integrate conveyors and have doors along their length to allow full body access for maintenance and product inspection.

Any safety system must ensure that the whole oven is isolated both electrically and mechanically should an operative need to enter the oven. Spooner Vicars chose a system with Allen Bradley Guardmaster rotary key switch isolator with electronic time delay and 32 dual access trapped key interlocks.

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