Method and apparatus for feeding chemicals into a process liquid flow

Abstract

A method of mixing at least two chemicals or additives into a process liquid flow flowing in a process liquid flow duct including: feeding a liquid jet to the process liquid flow in the process liquid flow duct, wherein the liquid jet is formed in a feeding device and the liquid jet flows in a transverse direction to a flow direction of the process liquid flow through the process liquid flow duct; mixing the at least two chemicals or additives together to form a mixture; feeding the mixture of the at least two chemicals or additives into the process liquid flow duct with the feeding liquid jet, and mixing the at least two chemicals or additives with the feeding liquid jet in the process liquid flow duct.

1 . A method of mixing at least two chemicals or additives into a process liquid flow flowing in a process liquid flow duct comprising:
 feeding a liquid jet to the process liquid flow in the process liquid flow duct, wherein the liquid jet is formed in a feeding device and the liquid jet flows in a transverse direction to a flow direction of the process liquid flow through the process liquid flow duct;   mixing the at least two chemicals or additives together to form a mixture;   feeding the mixture of the at least two chemicals or additives into the process liquid flow duct with the feeding liquid jet, and   mixing the at least two chemicals or additives with the feeding liquid jet in the process liquid flow duct.   
     
     
         2 . The method in  claim 1  further comprising introducing another chemical or additive to the feeding device before the mixing with the feeding liquid jet and the at least two chemicals or additives to the to the process liquid flow. 
     
     
         3 . The method in  claim 2 , wherein the another chemical is mixed with the feeding liquid substantially simultaneously with feeding of the feeding liquid to the process liquid flow. 
     
     
         4 . The method of  claim 1  wherein said process liquid flow includes a fiber suspension and the process liquid flow duct is in a paper machine headbox feed duct downstream of a machine screen. 
     
     
         5 . The method of  claim 1  wherein said at least two chemicals or additives include one or more of: fillers, binding agents, sizing agent, optical brighteners, antifoaming agents, retention chemicals, micro-particles, paper dyes and silicates. 
     
     
         6 . The method in  claim 1  wherein the at least two chemicals or additives are formed of one of the following pairs of chemicals or additives: retention chemical—filler, retention chemical—micro particle, retention chemical—sizing agent, silicate—filler, sizing agent—polymer, cationic polymer—anionic micro particle, and sizing agent—starch. 
     
     
         7 . The method in  claim 1  wherein said at least two chemicals or additives includes at least one of titanium dioxide, talc, kaolin, calcined kaolin, calcium carbonate, PCC, magnesium carbonate, calcium sulphate, barium sulphate, sodium silicate, aluminium trihydrate, and magnesium hydroxide. 
     
     
         8 . The method in  claim 5  where said sizing agent includes at least one of alkenylsuccinic anhydride, alkylketene dimer and a polymer. 
     
     
         9 . The method in  claim 5  wherein said retention chemicals are formed of micro-particles and polymers. 
     
     
         10 . The method in  claim 5 , wherein said micro-particle is at least one of colloidal silica, micro-polymer, bentonite, and polyethylene oxide. 
     
     
         11 . The method as in  claim 5  wherein said retention chemical is at least one of a cationic or an anionic acryl amid copolymer, colloidal silica, micro-polymer, bentonite, cationic starch, aluminum, PAC, polyethylenes, and polyamine. 
     
     
         12 . The method as recited in  claim 4  wherein a feeding point of said at least two chemicals or additives is at a point in the process liquid flow duct such that the mixture of said at least two chemicals or additives and fiber suspension is substantially homogenous at the latest when the mixture arrives from the headbox to the wire. 
     
     
         13 . An apparatus for feeding at least two chemicals or additives to a process liquid flow flowing in a process liquid flow duct, the apparatus comprising:
 a feeding device having a first inlet connection to receive a feeding liquid,   a second inlet connection for a first chemical or additive;   a feed connection for the feeding liquid and the chemical or additive,   a third inlet connection for a second chemical or additive introducing the second chemical or additive in the same space with the first chemical or additive within the feeding device.   
     
     
         14 . The apparatus in  claim 13  wherein the feeding device includes a feeding liquid space, a mixing liquid space and a chemical space. 
     
     
         15 . The apparatus in  claim 13  wherein in that said feeding device is arranged in flow communication with a paper machine headbox feed duct downstream of a machine screen. 
     
     
         16 . A method of mixing a plurality of chemicals or additives into a process liquid flow flowing in a process liquid flow duct comprising:
 forming a liquid jet in a feeding device which injects the liquid jet into the process liquid flow duct transversely to a flow direction of the process liquid flow through the process liquid flow duct;   mixing the chemicals or additives to form a mixture;   feeding the mixture directly into the process liquid flow duct using a pressure difference formed by the feeding liquid jet entering the process liquid flow duct, and   mixing the mixture of chemicals or additives with the feeding liquid jet in the process liquid flow duct.