Abstract:
The invention relates to a belt guide for short belt conveyors (1) in which an endless belt is passed over rollers (3, 4) at the ends of the conveyor. A plurality of glide strips (10) which extend generally in the direction of belt movement (7) beneath the upper run of the belt and over a stationary plane or surface (12). They are pivotal along the plane (12) about a respective pivot (11) in the proximity of the conveyor input end (8) and mutually connected for common angular movement around the pivots (11). The upper surface of respective glide strips (10) is proud of the common tangential plane of the end-rollers (3, 4) so that there can be generated between the glide strips (10) and the conveyor belt a contact pressure which is sufficiently great for the frictional force that acts laterall between the strips and the belt to enable lateral displacement of the belt in response to an angular change in the position of the glide strips (10).
Abstract:
A static mixer for mixing together gaseous and/or liquid media, comprising a casing (10) having media inlets and outlet (14-18; 19), and helical mixing elements (20, 21) extending therebetween, said mixing elements being stationary when the mixer is in use. Two or more mixing elements (20, 21) are arranged side-by-side in the casing (10), and each mixing element includes at least one flange (23) which extends helically through two or more turns along the length of the elements. The pitch of the helix is substantially greater than the flange thickness. The flanges (23) on the mixing elements (20, 21) extend helically in mutually the same direction, and the flange turns of each mixing element project into the spaces (24) between the flange turns of mutually adjacent mixing elements (20, 21).
Abstract:
A method of chlorine free bleaching of pulp where the metals in the pulp are removed by means of a chelating agent. The pulp is treated with the chelating agent at a pH 2-7 for a period of 5 minutes to 2 hours. The chelating agent is activated by the addition of an oxidizing agent. After the treatment the pulp is washed.
Abstract:
A device for compressing and processing a material mat at the manufacture of board of lignocellulosic material, comprising rotary compression rolls. At least one of the compression rolls (2) is formed with a perforated shell surface (6) and an axial duct system (7) located inside of the shell surface. A slide shoe (8) abuts sealingly the end wall of the roll (2) for injection of the processing medium to the mat via the duct system (7) in a restricted sector (9) of the roll (2) where the mat is compressed.
Abstract:
A refiner segment for disc refiners for desintegration of lignocellulose-containing material, where the refiner segment (1) is formed with a pattern of bars (2) and grooves (3), and where dams (4) are placed in the grooves. The dams (4) are so arranged that their angle in relation to the radius of the refiner segment (1) is smaller than 30 DEG .
Abstract:
Board of lignocellulose-containing material and a method of manufacturing such board. The material is disintegrated to particles or fibres, dried, glued prior to or after the drying, formed to a mat and finally dried by hot pressing to a finished board. According to the invention, the lignin is modified chemically at least in the surface layer of the particles or fibers prior to the final drying, so that an increased binding reactivity is obtained by the introduction of hydrophilic groups and so that the softening temperature of the lignin is lowered. Thereby the lignocellulose material in the board is partially sulphonated so that the organically combined sulphur exceeds the native sulphur content of the material but is lower than 0.4 %.
Abstract:
A method of treating process water containing metal ions in connection with bleaching pulp of ligno-cellulose-containing material. The process water is brought into contact with an alkaline liquid, which preferably also contains sulphide, whereby metal ions precipitate in the form of difficultly soluble metal compounds. The precipitated metal compounds thereafter are separated from the process water.
Abstract:
In an improved method for measuring the distance (B) between two mutually opposing surfaces (1, 2) by means of the reluctance method, there is used a position indicator (4) whose measuring device (9) is mounted on an associated core (6) arranged on one (1) of the two surfaces. The other (2) of the surfaces is provided either with a permanent magnet or an electromagnet (14). When the opposing surfaces rotate in relation to one another (R), the distance can be measured with the aid of a winding whose induced electromotive force constitutes a measurement of the distance to be measured. A value of the sought distance can also be obtained with the aid of a Hall-element (9), which in the detection of a static magnetic field produces an electric current value which constitutes a measurement of the distance to be measured. The magnetic field is balanced with the aid of a coil (N2) mounted on the core, thereby enabling the distance to be measured by measuring the adjusting current supplied to the balancing coil. When the magnetizing device (M) on the other surface has the form of an electromagnet, the current supply to the device and to a further balancing coil (N2') on the core is advantageously an alternating supply.
Abstract:
A method of controlling oxygen delignification of pulp, i.e. reduction of the kappa number of the pulp, where the delignification is carried out in two stages, and the main portion of the chemicals required for the delignification is added to the first stage. The ingoing kappa number of the pulp prior to the delignification and the reduction of the kappa number of the pulp during the total delignification in the two stages are used for adjusting the chemical addition to the first stage. The control is carried out so that higher ingoing kappa number yields lower charge and higher kappa number reduction yields higher charge, calculated per reduced kappa number unit. Said chemical addition to the first stage in its turn is used for control the temperature in the second stage.
Abstract:
A method for bleaching paper making pulp with peroxide with enhanced efficiency for a chelating stage wherein the pulp after digestion, and possibly oxygen bleaching, is subjected to a mild chlorine dioxide treatment at acidic pH, an alkalization and a treatment with chelating agent at a high pH before a peroxide stage.