Abstract: In an axial fan having an impeller with settable blades and wherein the root end of each blade connects, via a bearing permitting rotation of the blade, to the outer end of a blade-attachment shaft extending substantially radially relative to the impeller, the blade-attachment shaft is rigidly connected at its inner end to an impeller hub. The blade-attachment shaft is abutted against the radial outer side of the hub and is pre-tensioned by compressing said shaft in the longitudinal direction thereof against said hub.

Abstract: There is provided an axial fan having a fan wheel with settable blades, each blade being rotatably mounted at its root end about an axis which extends substantially radially relative to the fan wheel, and carries a setting arm which projects radially outwardly relative to the blade axis, said arm being connected via a movement-transmission arm to a setting device which is common to all said blades and which is displaceably mounted on the fan wheel for movement in the axial direction thereof to change the blade angle. The setting device is also rotatable coaxially in relation to the fan wheel, and each movement-transmission arm is rigidly connected at one end thereof to the setting device. The other end of the movement-transmission arm is mounted in the associated setting arm for both axial and universal movement.

Abstract: A method for manufacturing fan blades which are adjustable in operation. The adjusting means comprises a compressed air box for actuating each fan blade by means of a dog member, said box and said member being non-rotatable on the fan wheel axle. The fan is easy to construct to different demands for capacity due to the fact that fan blade shafts are made in a number of exchangeable preselected standardized sizes and always has the same above mentioned arrangements for the rest of the fan.