The invention relates to a mineral wool centri¬ fuge comprising a rotatable centrifuge wheel for the defibration of a molten mineral material to be passed on to said centrifuge wheel; a driving motor for the rotation of the centrifuge wheel; a blowing air nozzle /blowing air nozzles for applying blowing air to the periphery of the centrifuge wheel for separating min- eral fibres from the molten mineral material; and means for applying a binder to the mineral fibres sep¬ arated from the periphery of the centrifuge wheel.

A conventional mineral wool centrifuge general¬ ly comprises three to four centrifuge wheels. The cen- trifuge wheels form a group in which each centrifuge wheel rotates in a predetermined direction, casting centrifugally molten mineral material from the periph¬ ery thereof on to the periphery of an adjacent cen¬ trifuge wheel. The entire group is placed in a car- riage displaceable on rails under a melting furnace. The carriage further comprises a blower or the car¬ riage is connected to an external blower for producing the blowing air which is passed around the centrifuge wheels in the direction of the axes thereof. By means of the blowing air, the molten mineral material is party extended into fibres and the fibres thus formed are transported into a wool chamber. Each centrifuge wheel is rotated by a separate motor by means of a V- belt drive. The motors are placed under the protective plates of the carriage.

The above-described asymmetric mineral wool centrifuge arrangement and the motors, blowers, air pipes, water cooling means for the centrifuge wheels, etc., comprised therein form a relatively large, clum- sy structure. The centrifuge is heavy and thus diffi-

cult to handle. It takes plenty of space under the melting furnace and the air flow into a collecting chamber forming an extension thereof is difficult to control. In addition, this kind of mineral wool cen- trifuge is difficult to maintain.

The object of the present invention is to pro¬ vide a new mineral wool centrifuge the shape of which in particular is improved and by means of which the above disadvantages can be avoided in a simple manner. This object is achieved by means of a mineral wool centrifuge according to the invention, which is char¬ acterized in that the centrifuge comprises an unro¬ tatable body shaft; the driving motor is fastened di¬ rectly to the end face of the body shaft, whereby the body shaft and the driving motor form a coaxial, fix¬ ed, unrotatable whole; and a drive shaft of the driving motor for the rotation of the centrifuge wheel is arranged to extend through the body shaft so that the end portion of the drive shaft protruding from one end of the body shaft is connected to the centrifuge wheel mounted in bearings on the body shaft.

The invention is thus based on the idea that each centrifuge wheel is provided with its own stream¬ lined unit which comprises all means required for defibration and forms a small whole easy to handle so that the defibration operations can be carried out and controlled therewith more easily than previously.

The structure according to the invention en¬ ables the introduction of the blowing air to be passed around the centrifuge wheel to be effected in a new way. It is preferable to fasten the blowing air nozzle(s) to the body shaft around it, and the driving motor is surrounded by a tubular shell which extends up to the blowing air nozzle(s) so as to form an annu- lar blowing air channel which extends past the driving

motor and is connected to the blowing air nozzle(s). The defibration air advancing in the annular blowing air channel thus simultaneously cools the structures within the shell, particularly the driving motor, whereby it has been preheated when it reaches the cen¬ trifuge wheel, which is advantageous in view of the defibration.

By virtue of the unrotatable body shaft the cooling of the centrifuge wheel and the lubrication of the bearings are also easy to arrange.

In addition, the use of the mineral wool cen¬ trifuge according to the invention enables the sur¬ roundings of the melting furnace of the mineral ma¬ terial and the wool chamber to be planned more freely in the premises used for the production of mineral fibres.

In the following the invention will be de¬ scribed more closely with reference to the attached drawing, which shows a longitudinal section of a in- eral wool centrifuge according to the invention.

The mineral wool centrifuge comprises an unro¬ tatable body shaft to the face face of which is di¬ rectly attached a direct-coupled driving motor 2 having a speed of rotation preferably within the range from 3,000 to 10,000 r/min and a soft start-up and stop. The speed of rotation of the motor is adjusted with an AC inverter. The body shaft 1 and the driving motor 2 thus form a coaxial, fixed unrotatable whole. The centrifuge wheel 3 is mounted in bearings on the body shaft 1 at a distance from the driving motor 2 and a drive shaft 4 of the driving motor is arranged to extend through the body shaft, so that the end por¬ tion of the drive shaft protruding from one end of the body shaft is connected to the centrifuge wheel by means of a coupling 5. An annular blowing air nozzle 6

is arranged around the body shaft 1. The driving motor 2 is surrounded by a tubular shell 7 which ex¬ tends up to the blowing air nozzle 6 so as to form an annular blowing air channel 8 which extends past by the driving motor and is correspondingly connected to the annular blowing air nozzle. The passage of the blowing air is illustrated by means of the arrows A. A binder feeding channel 9a, 9b is arranged to extend through the driving motor 2 and the drive shaft 4 thereof into a binder spraying apparatus 17 attached to the end face of the centrifuge wheel.

Means 10 for feeding cooling water into the centrifuge wheel 3 is fitted fixedly on the body shaft 1 adjacent to that end of the centrifuge wheel which faces the driving motor 2. The cooling water is introduced into the centrifuge wheel through channels 11 positioned at the end face thereof by means of a chute 12 extending around the end face of the centri¬ fuge wheel, whereafter is circulated within the cen- trifuge wheel and discharged out of the centrifuge wheel through further channels 13 positioned at the end face of the wheel, the channels 13 being position¬ ed at a greater radial distance from the axis of rota¬ tion of the centrifuge wheel than the channels 11. The circulation of the cooling water within the centrifuge wheel 3 takes place by means of the centrifugal force. The water to be removed is passed into a chute 14 which is similar in structure to the chute 12 and which extends around the centrifuge wheel. The cooling water is removed from the chute 14 by means of a cool¬ ing water collecting means into a cooling water return pipe 16 which is positioned in the blowing air chan¬ nel 8 similarly as the feeding pipe not shown in the drawing. The circulation of the cooling water within the centrifuge wheel 3 is illustrated by arrows.