Abstract: According to the process, limestone is burned at a high temperature to form calcium oxide and, thereafter, calcium carbonate is formed from calcium oxide in the presence of water and carbonate ions and the formed calcium carbonate is recovered. The formation of the carbonate may be performed by carbonating calcium oxide with carbon dioxide gas in the presence of water or water vapour, or by reacting calcium oxide with soda solution. According to the invention calcium oxide is converted to calcium carbonate without separate slaking and essentially without intermediate storage, in particular without intermediate storage between the burning of the starting material and the forming of calcium carbonate. With the aid of the invention a quite advantageous solution in view of heat economy is achieved.

Abstract: Method and assembly for forming a paper or board web and a product made using the method. According to the method, the web (11) is made from fibers and then the web (11) is treated with pigment particles. The web is treated with microscopic pigment particles whose average size is so small as to permit the particles to adhere to each other by van der Waals forces. The particles are transferred to the web and adhered thereto advantageously using an ion-blast technique.

Abstract: Method and assembly for forming a paper or board web and a product made using the method. According to the method, the web (11) is made from fibers and then the web (11) is treated with pigment particles. The web is treated with microscopic pigment particles whose average size is so small as to permit the particles to adhere to each other by van der Waals forces. The particles are transferred to the web and adhered thereto advantageously using an ion-blast technique.

Abstract: Method and assembly for forming a paper or board web and a product made using the method. According to the method, the web (11) is made from fibers and then the web (11) is treated with pigment particles. The web is treated with microscopic pigment particles whose average size is so small as to permit the particles to adhere to each other by van der Waals forces. The particles are transferred to the web and adhered thereto advantageously using an ion-blast technique.

Abstract: Method and assembly for forming a paper or board web and a product made using the method. According to the method, the web (11) is made from fibers and then the web (11) is treated with pigment particles. The web is treated with microscopic pigment particles whose average size is so small as to permit the particles to adhere to each other by van der Waals forces. The particles are transferred to the web and adhered thereto advantageously using an ion-blast technique.

Abstract: A rotating electric machine (1) has a rotor, a stator (2), and stator windings (3, 4). The windings (3, 4) include high voltage cable drawn through slots (5, 6) in the stator (2). Support members (8) are arranged inside the slots (5, 6) along and in contact with the windings (3, 4), said support members (8) comprising a hose (8′) with a substantially triangular cross-section. A wire (9) is extending through and being attached to each support member (8). When mounting the support members (8) air inside a support member (8) is evacuated in order to shrink the support member (8). Then the wire (9) extending through the support member (8) is used to pull the evacuated support member (8) into a slot (5, 6), whereupon the evacuated support member (8) is expanded by releasing the vacuum inside in order to make it clamp a cable inside a slot (5, 6) of the stator (2).

Abstract: The present invention concerns a process for preparing calcium carbonate pigment from calcium oxide and/or calcium hydroxide and carbon dioxide in the presence of water. According to the invention, the starting materials are reacted in fluid state containing at least 20 parts of volume of gas for each part by volume of suspension formed by water and solid substances, and the amount of water is essentially equivalent to the amount which is evaporated during the reaction together with the amount left in a calcium carbonate product which behaves like a powder. By means of the present invention, PCC in powder form can be prepared without the product first having to be separated from a slurry.

Abstract: Method and assembly for forming a paper or board web and a product made using the method. According to the method, the web (11) is made from fibers and then the web (11) is treated with pigment particles. The web is treated with microscopic pigment particles whose average size is so small as to permit the particles to adhere to each other by van der Waals forces. The particles are transferred to the web and adhered thereto advantageously using an ion-blast technique.

Abstract: The invention concerns precipitated calcium carbonate products containing polynuclear regular agglomerates having a number of calcium carbonate particles (aggregates) attached to each other and having a particle size of about 40 to 200 nm. According to the invention, these products are prepared by adjusting the Z potential of the calcium carbonate suspension to −1 . . . −20 mV by adjusting the pH of the suspension to 6.5 . . . 9.5. The pH of the calcium carbonate slurry obtained by causticizing is adjusted to a desired value in a box filter, where after the suspension is stirred by a heavy-duty mixer such that it is subjected to differences of about 50 to 200 m/s in peripheral speed. The products according to the invention have good opacity and are very well suited for coating paper.

Abstract: The invention is related to a method for forming calcium carbonate. In the method, calcium oxide is reacted with carbonate ions in the presence of water to produce calcium carbonate. According to the invention, the formation is carried out directly from calcium oxide to calcium carbonate without intermediate stages in a three-phase precipitation, whereby the hydration of the calcium oxide to calcium hydroxide and the carbonation of the hydrated part are carried out immediately after one another under so intensive agitation that the calcium carbonate elements thus created are detached from the surface of the calcium hydroxide. The mixing is preferably carried out in a fluid medium where the amount of gaseous phase is at least 20 parts by volume and the amount of liquid phase is 0.5 to 1 part per one part by volume of the solid matter of the suspension. In the process, the desired end product, PCC, can be prepared in a very short residence time and with a small operational content.

Abstract: A process and an apparatus for the preparation of precipitated calcium carbonates calcium hydroxide using gaseous carbon dioxide, whereby the carbonation is performed in a gaseous phase by mixing calcium-hydroxide-containing liquor mist with the carbon dioxide gas in a turbulence having an energy intensity in excess of 1000 kW/m3. The reaction is advantageously carried out in an apparatus, comprising at least two serially arranged pin mills having one or more rotatable vane rings which can be used to impose a great energy intensity on the material which is fed into the apparatus, whereby the first pin mill is provided with at least an inlet for slaked lime and carbon dioxide and an outlet for the reaction product, and the second pin mill is provided with an inlet for the product from the previous mill and an outlet for the reaction product. Carbonating is extremely swift. The residence time of the reaction is even less than 1 second.

Abstract: This invention relates to a pigment particle product and a method for its preparation. According to the invention pigment particles, such as kaolin, natural calcium carbonate or titanium dioxide, and precipitated calcium carbonate are mixed together in an aqueous phase at pH 6-11, which causes the pigment particles to become coated with particles of precipitated calcium carbonate. The brightness of the product is excellent, and it is quite inexpensive to produce.

Abstract: The invention concerns a prestressed construction element of composite structure comprising a bar- or tendon-like inner part (1) of high tensile strength, a sheat part (2) of, e.g., high-strength concrete or ceramic material, adapted about and precompressed by the inner part (1), and a shape-forming structure (4) adapted about the sheath part (2) with dimensions corresponding to the desired dimensions of the construction element. According to the invention, the structure (4) is such an elastic material as is capable of taking both compression and tensile stresses without cracking. The construction in accordance with the invention achieves a strong and easily workable construction element.

Abstract: The invention concerns a method for producing a hardened mineral product, especially concrete. The method utilizes a hydration reaction with water for at least 1 hour, preferably for 4 to 40 hours, by producing a water/binding agent paste containing components for retardation of binding agent crystallization together with other possible admixtures, e.g., accelerators. When the binding agent reaches an appropriate degree of hydration, preferably 10 to 90%, the unset paste is complemented with fillers for producing the desired mineral mix, after which the end product is shaped as desired and hardened. The water/binding agent paste is agitaged in order to promote the hydration reaction, and when required, admixed with an additional amount of the retarding component of the binding agent crystallization. Furthermore, the invention includes an apparatus for hydrating the binding agent with a facility for subjecting the paste to compacting pressurization in order to improve hydration.

Abstract: Apparatus for manufacturing a hollow concrete slab by a slide casting operation. The slab is formed with one or more cavities through the use of tubes of flexible material into which a pressurized medium, particularly water, is fed. The apparatus comprises a stationary base and a casting device arranged to travel in the longitudinal direction of the base. A number of parallel shaping pipes forming part of the travelling casting device and having a cross section corresponding to the desired cross section of the cavities to be formed are opened at both ends. The flexible tubes, which are fastened at their rear ends, to a pressured liquid source pass during the casting process from reels in the casting device through the pipes so as to give the cavities their final form.

Abstract: Hydraulically driven percussion device, comprising a piston reciprocally movable within a body and striking against a tool, said piston defining with reference to the body two cylinder spaces, one of which continuously communicates with the high pressure duct and the other by the aid of a distribution means alternatingly connectable to the high pressure duct and the low pressure duct. At both ends of the piston there are breathing chambers opening into the free atmosphere. Within one of said two cylinder spaces a sleeve-like distribution means has been placed to encircle the piston and which distribution means, in order to move into a position such that movement of the piston directed towards the tool becomes possible, is controlled by means of grooves provided in the piston and in the body when the piston is in its end position farthest removed from the tool and only on condition that the pressure in the high pressure duct exceeds a pressure set with an adjustable valve incorporated in the body.