All fired up for Safety

Let’s take a look at a cold rolling mill in which steel strip coils are processed. The pro­duc­tion process includes five steps: pick­ling, cold rolling, annealing, tem­pering and then fin­ishing. The chal­lenge? The fre­quent shut­ting down of the start-up burners, which ignite the main burners.

The start-up burners were con­trolled by only one module, while flame mon­i­toring occurred via UV cells at the igni­tion. As a result, trou­bleshooting became a puzzle: if a UV cell was defec­tive the whole mill stopped. Restart dragged on because unburned gases con­taining nitrogen had to be expelled first. And the defec­tive UV cell had to be replaced – although one never knew which UV lamp actu­ally failed. As this little story demon­strates: time is an impor­tant factor in areas where fire and its asso­ciates define the pro­duc­tion activ­i­ties. Not only the smooth but above all the safe oper­a­tion of this type of mill depends on the right timing.

Cool safety manager for hot work

This explains why the require­ments for product and process safety and health and safety are so high. Any­thing else would risk a fire or explo­sion, irre­spec­tive of whether it involves burners with oil, gas, coal or other flam­mable sub­stances, whether boilers or fur­naces. Modern burner man­age­ment sys­tems for auto­mated oper­a­tion of a burner instal­la­tion must there­fore have a com­plex design and must meet a number of inter­na­tional stan­dards.

With the base unit PNOZ m B1 Burner of the safe small con­trollers PNOZ­multi 2 the entire fur­nace can be con­trolled and mon­i­tored safely, including the appli­ca­tion-spe­cific safety func­tions up to PL e/SIL 3.

Pilz offers two fail­safe system solu­tions with its small con­trollers ­PNOZ­multi – with base unit PNOZ m B1 Burner – and automa­tion system PSS 4000 – with the con­troller PSSuni­versal PLC: From smaller machines – such as waffle baking ovens – to com­plex net­worked plants – such as for ­example in the metal, glass and ceramics industry where a dozen burners across exten­sive pro­duc­tion areas with a large number of inputs and out­puts are common – they always ensure that any fiery hap­pen­ings are safe and under con­trol. They reli­ably manage, for example, the mon­i­toring of pres­sure, tem­per­a­ture and flames, safe run-through of the sequence for starting up and switching off the burner instal­la­tion or even the safe mon­i­toring of the fuel/air ratio. This increases pro­duc­tivity, not least through inte­grated, com­pre­hen­sive diag­nos­tics.

Which brings us back to our little story: After the automa­tion system PSS 4000 took over burner man­age­ment in the cold rolling mill, the tech­ni­cians them­selves have been reporting “peaceful nights” – late-night trou­bleshooting trying to find that one lamp is now a thing of the past!

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