Device for diluting shredded cellulosic particles/chips
The device is for the dilution of dewatered cellulose pulp that maintains a consistency of 20-30% or greater. By shredding of the pulp to a finely divided dry-granulate, dilution to a homogeneous consistency in the medium consistency range can take place exclusively through hydrodynamic effects from the addition of dilution fluid. The dilution fluid is added to granulate at a position at which granulate is in free fall in a standpipe and above a level Liq lev of diluted pulp in the standpipe. A number of nozzles are arranged around the periphery of the stand pipe, directed in towards the center of the stand pipe, obliquely downwards in the direction of fall of the granulate. It is possible through this simplified procedure to avoid completely the conventional dilution screws, and this reduces the investment costs and operating costs, while at the same time unnecessary mechanical influence of the pulp fibers can be avoided.
1. A device for the dilution of dewatered cellulose pulp, comprising; shredder screw means for fragmenting pulp to a particle size in an interval of 5-40 millimeters, the shredder screw means having an outlet defined therein, the shredder screw means containing the fragmented pulp, a vertical standpipe connected to the outlet of the shredder screw means, the standpipe carrying a flow of the fragmented pulp flowing under free fall, the standpipe having a distribution chamber defined therein at an upper end of the stand pipe, the distribution chamber arranged concentrically around the standpipe, at least four nozzles arranged around a circumference of the distribution chamber, the nozzles being oriented inwardly towards a center of the flow to add a dilution fluid under pressure into the stand pipe, the nozzles being disposed above a liquid level of diluted pulp established in the standpipe, a feed arrangement disposed at a bottom of the standpipe for feeding the pulp to subsequent treatment stages, a pump disposed at the bottom of the standpipe and in operative engagement with the feed arrangement, and the standpipe having no mechanical agitator disposed above the liquid level.
2. The device according to claim 1 wherein the device has the pump connected to the standpipe at a lower part thereof close to the bottom of the standpipe under the liquid level.
3. The device according to claim 1 wherein the nozzles are arranged around a periphery of the stand pipe, where a distance between neighboring nozzles is less than 50-300 mm.
4. The device according to claim 3 wherein each nozzle is directed at an angle relative to a direction of free fall of the fragmented pulp of 45 degrees±15 degrees.
5. The device according to claim 4 wherein all nozzles are connected to a common distribution chamber for dilution fluid, and the distribution chamber is pressurized through a pressure-raising device.
6. The device according to claim 1 wherein the nozzles are oriented obliquely downwardly.