When the main­te­nance staff for the air condi­tioning at the site dropped by at the old supply fan as part of their routine checks, they were aston­ished: the massive fan, with a diam­eter of over two meters, was damaged beyond repair. This was caused by vibra­tions that broke the conveyor blades, so the approx­i­mately thirty-year-old fan had finally been killed off.

This was not discov­ered imme­di­ately. “The system venti­lates a rela­tively small manu­fac­turing area as well as halls currently used as a ware­house. During routine checks, we asked ourselves why it was so quiet, then we saw it: blade breakage, total damage that caused it to disas­semble itself,” explains Jens Goßmann, respon­sible for process opti­miza­tion at Cordenka.

Strict require­ments, high-quality replace­ments

At some point, everyone gives up: since the 30-year-old fan could no longer with­stand the vibra­tions of the drive, which was not oper­ating smoothly, even the blade broke. (Photos: HDS, Cordenka))

The company, which is head­quar­tered in Obern­burg am Main, has been producing tech­nical viscous fibers since the factory was founded in 1924 and is now the leading manu­fac­turer of tech­nical rayon thread, which is predom­i­nantly used for car tires. For this reason, it is a matter of course that all machines, which are oper­ated by around 600 employees, are of an outstanding quality. A high-quality, long-term reli­able replace­ment was there­fore required for the defec­tive fan. Since Cordenka had already worked with ebm-papst, Goßmann approached the company directly and was referred to HDS GmbH, who took care of the plan­ning process as a service partner of ebm-papst. Everyone started working together.

A hundred-year-old factory building, a large axial fan, a small service door: “The fan could not be replaced like-for-like without labo­rious building measures. We had to disas­semble it into indi­vidual parts to get it out in the first place.” That is why Goßmann and HDS also planned for the tiny door when orga­nizing the replace­ment – and decided on a fan wall. “With a modular design, you can create the same perfor­mance and also have greater flex­i­bility: many old fans are located in small cellars, in which they are often fixed into a wall,” explains Jens Gerner, who led the project at HDS together with his colleague Jens Martin.

Up until then, the old axial compact fan could only be switched ‘on’ or ‘off’. So that energy does not liter­ally vanish into thin air, we had already closed venti­lation ducts that were not required in the ware­house in some cases. Jens Goßmann

100,000 cubic meters of air flow per hour: this maximum power had to be repro­duced using the RadiPac series’ EC centrifugal fans. “A 08/15 fan cannot achieve that.”

From axial to centrifugal

HDS planned the FanGrid with eight Radi­Pacs and supplied them in a modular system as indi­vidual modules and pre-assem­bled.

There­fore, HDS planned the FanGrid with eight Radi­Pacs and supplied them in a modular system as indi­vidual modules and pre-assem­bled. From this point on, Cordenka’s service providers took care of assembly and connec­tion. “The HDS plans were very good and the instal­la­tion went smoothly,” says Goßmann. The new modules have been in oper­a­tion for four months and run smoothly. And that is not all: they are infi­nitely adjustable.

“Up until then, the old axial compact fan could only be switched ‘on’ or ‘off’. So that energy does not liter­ally vanish into thin air, we had already closed venti­lation ducts that were not required in the ware­house in some cases.” Cordenka can now also regu­late the air flow into the supplied manu­fac­turing facility because of the fans’ control char­ac­ter­is­tics, which actively saves energy. If produc­tion begins again in the ware­house at a later time, the venti­lation ducts will be opened again and the fans will be adjusted appro­pri­ately. And if, contrary to expec­ta­tions, a fan has a problem in the future, seven more fans will effort­lessly pick up the slack it is repaired. At present, Cordenka is already testing how air quality can be improved using the fan wall.

The FanGrid with eight RadiPac EC centrifugal fans, which was planned by HDS, makes perfect use of the tight space thanks to a tailor-made design...

and supplies the asso­ci­ated halls with a maximum air flow of 100,000 m³/h with a maximum elec­trical total power of 19kW. (Photos: HDS)

For the successful project, Cordenka was awarded BAFA Module 1 support for using effi­cient cross-section tech­nolo­gies. In the future, further retro­fits with EC centrifugal fans could also be planned. “These have the advan­tage that they can be easily accom­mo­dated in rela­tively small rooms and can be inte­grated into intel­li­gent control systems. This enables us to use them according to require­ments and in a way that is more energy-effi­cient.”