35F / 35FD Twin Shaft®

New 35F / 35FD blade with FRP pultruded shaft represent the most suitable product for Wet application with VFD device, combining the unique advantages of the flexible design together with the high resistance against corrosion effects.
Special root cap design determines a total efficiency increase reducing reverse airflow effects and allowing a better flow distribution along the blade.

The patented 35F /35FD Twin shaft^® solutions are availabe from 20 ft diameter up to 40ft (12.192 m) diameter with different G hub configurations to optimize blade length and natural frequency values. Combination of different materials and painting cycles offers the perfect solution to resist under the most aggressive environmental conditions, including offshore and seawater applications.

Cofimco’s extensive research and laboratory test have resulted in the development of a new innovative shaft to connect the blade air foil to the hub, the new pultruded FRP shaft with carbon-fiber. The innovative shaft material gives the blade a suitable elasticity, between a flexible and rigid connection. As a result, vibration introduced by the fan to the supporting structure is noticeably reduced. The blade equipped with the innovate shaft is made with a traditional aerodynamic airfoil, fixed to the shaft by means of bolts.

Special root and tip caps are fixed to the airfoil by mean of rivets.

The 35F / 35FD Cofimco fan blade is the first and only worldwide blade with pultruded FRP shaft with carbon-fiber, the following goals are achieved using the innovative material and dampening shaft design:

The vibrations and loads introduced by large fan blades in the supporting structure are greatly reduced thanks to the resulting blade elasticity, midway between flexible and rigid links.
The fan blades are able to withstand severe duty points and manage the high abrupt loads frequently introduced to the blades of large fans.
Drive system life is extended and supporting structure preserved. This new material and design represent a great improvement in the blade shaft strength and performance.

Main applications: