| 摘要 |
Plate-like or cylindrical or tubular insulating elements are made from mineral wool, e.g. stone-wool or glass-wool by immersing the material, while contained in a mould having a perforated circumferential wall, in a liquid synthetic resin-based binding agent such that the synthetic resin penetrates into the fibrous material only superficially. A suitable synthetic resin is melamine-formaldehyde resin. The mineral wool is supplied on a conveyer belt between a pair of rollers and thereby formed into a coherent layer with a thickness of about 1/4 in. under a slight pressure. The layer is wound on a core to the desired thickness and then placed in the perforated mould which is immersed in the liquid binding agent. The fibrous body impregnated with liquid and while still in the mould is rapidly rotated and thereafter dried and hardened. By this means the excessive liquid is thrown out of the body and by the centrifugal action the liquid in the body is driven out from the interior. The body is thus strengthened on its outer side while the insulating capacity of its inner side is increased. To this end a mould containing the fibrous mass is clamped into a rotating head in such a manner that a hollow space is formed around the axis of rotation. Through a bore in the rotating head a hot gas is introduced into the hollow space and flows through the fibrous layer in the direction of the centrifugal force and out through the perforated mould walls. When insulating elements for pipe-lines are being made, the cylindrical core is withdrawn from the fibrous body after the immersion step, hot gas being introduced into the interior of the cylinder-shaped element during the centrifugal step. Plate-shaped fibrous bodies are obtained in flat moulds and the moulds may be joined to a polygonal drum for subjecting them to the centrifugal step. |
