Apparatus and method for manufacturing mineral wool as well as a mineral wool product

A method of manufacturing mineral wool, the method comprising:

• producing a molten mineral material;
• feeding the molten mineral material into a plurality of fiberizing devices including a first fiberizing device for forming a first group of fibers and a second fiberizing device for forming a second group of fibers, each of the fiberizing devices comprising, rotationally arranged around a vertical axis, a fiberizing plate having a vertical peripheral edge, into which are formed a plurality of holes, through which the molten material is led by centrifugal force to form the fibers;
• directing an annular flow of blowing medium downwards around each of the fiberizing devices to cause the fibers to turn downwards and to thin;
• conveying the first group of fibers by a first conveying means to a collection device;
• and
• conveying the second group of fibers by a second conveying means to the collection device;
• and
• forming a mat-like material in the collection device using the first group of fibers and the second group of fibers;
• wherein the collection device comprises a collection chamber, a collection drum having a perforated surface, and a suction box arranged inside of the collection drum;
• and
• wherein a height of the first fiberizing device relative to the collection device is different from a height of the second fiberizing device relative to the collection device.