Method and Apparatus for Feeding Chemicals Into a Process Liquid Flow

Abstract

A method and apparatus for feeding a retention chemical together with an additive, which may be another chemical or for example a mineral, to paper suspension flow in a paper machine. The method and the apparatus are applicable to the simultaneous feeding of an additive of the paper manufacture, such as a filler, together with a retention chemical to paper pulp.

1 . A method of feeding chemical into a process liquid flow said method comprising:
 spraying a chemical to said process liquid flow with a feeding liquid jet created a feeding apparatus and having a transverse direction in relation to said process liquid flow whereby the chemical is mixed the feeding liquid substantially simultaneously with said spraying of the chemical, and   feeding at least one of a further chemical and additive with the feeding liquid jet to the process liquid.   
     
     
         2 . A method as recited in  claim 1 , wherein said at least one of the further chemical and the additive is fed to said feeding apparatus before being introduced to the process liquid flow. 
     
     
         3 . A method as recited in  claim 1 , wherein said at least one of the further chemical and additive flows into a space in said feeding apparatus, wherein the space is separate from the mixing of feeding liquid and chemical. 
     
     
         4 . A method as in  claim 1 , wherein said at least one of the further chemical and additive flow into a space provided in said feeding device. wherein said space receives at least another chemical and additive. 
     
     
         5 . A method as in  claim 1 , wherein said at least one of the further chemical and additive flows into at least one of a feeding liquid space in said feeding apparatus and a flow duct feeding liquid to said feeding liquid space. 
     
     
         6 . A method as in  claim 1 , wherein said at least one of the further chemical and additive is added at a process pressure to a duct transporting said process liquid flow. 
     
     
         7 . A method as in  claim 1 , wherein said at least one of the further chemical and additive is added to a process liquid duct transporting the process liquid flow at a process pressure and is fed to the process liquid flow by feeding liquid jet discharged from the feeding apparatus. 
     
     
         8 . A method as in  claim 1 , wherein said process liquid includes a fiber suspension flowing in a paper machine headbox feed duct downstream of a machine screen. 
     
     
         9 . The method as recited in  claim 8 , wherein at least one of a fillers, binding agents, sizing agents, optical brighteners, antifoaming agents, two-component and multi-component chemicals is fed into the fiber suspension flow after the machine screen. 
     
     
         10 . The method as in  claim 8 , wherein the at least one of a retention chemical and filler, retention chemical and micro particle, retention chemical and sizing agent, silicate and filler, and sizing agent and polymer is fed into the fiber suspension flow after the machine screen. 
     
     
         11 . The method as recited in  claim 9 , characterized in that wherein said filler is 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. 
     
     
         12 . The method as recited in  claim 9 , wherein said sizing agent is at least one of an ASA sizing agent, AKD sizing agent, polymer and corresponding substance. 
     
     
         13 . The method as recited in  claim 9  wherein said retention chemical includes micro particles and polymers. 
     
     
         14 . The method as recited in  claim 9  wherein said micro particle is at least one of colloidal silica, micro polymer and bentonite. 
     
     
         15 . The method as recited in  claim 10  wherein said retention chemical is at least one of a cationic acryl amide copolymers, an anionic acryl amid copolymers, a colloidal silica, a micro polymer, bentonite, cationic starch, alum, PAC, a polyethylene, and a polyamine. 
     
     
         16 . A method as recited in  claim 1 , wherein a feeding point of said at least one of the further chemical and additive occurs such that a mixture of said at least one further chemical and additive and the paper pulp is substantially homogenous when the mixture arrives from the headbox to the wire. 
     
     
         17 . A method as recited in  claim 1 , wherein said at least one of the further chemical and additive is a retention chemical, a micro particle, filler, binder, sizing agent, optical brightener, paper dye and silicate. 
     
     
         18 . An apparatus for feeding chemical into a process liquid flow, the apparatus comprising:
 a feeding apparatus for feeding at least one chemical to said process liquid flow, wherein the feeding apparatus includes a nozzle spraying the chemical to the process liquid flow;   the nozzle including a feeding liquid jet having a transverse direction in relation to the process liquid flow whereby the chemical is mixed with the feeding liquid substantially simultaneously with the spraying action, and   a connection to the feeding apparatus for feeding additional chemical to a process liquid flow duct.   
     
     
         19 . An apparatus as recited in  claim 18 , wherein the process liquid is paper pulp and said connection is located in the flow duct of the paper pulp upstream of the feeding apparatus so that the chemical flowing from said connection to the flow duct is conveyed with the paper pulp flow to an opening of the feeding apparatus. 
     
     
         20 . An apparatus as in  claim 18 , wherein the feeding apparatus includes a feeding liquid space, a mixing liquid space and a chemical space into which each of the media mentioned is introduced by of flow ducts. 
     
     
         21 . An apparatus as in  claim 18  wherein said connection is in flow communication with a feed liquid space of said feeding apparatus. 
     
     
         22 . An apparatus as in  claim 18 , wherein said connection is in flow communication with a mixing liquid space of the said feeding apparatus. 
     
     
         23 . An apparatus as in  claim 18 , wherein said connection is in flow communication with a chemical space said feeding apparatus. 
     
     
         24 . An apparatus as in  claim 18 , wherein said connection is in flow communication with a flow duct bringing medium to the said feeding apparatus. 
     
     
         25 . An apparatus as in  claim 18 , wherein said feeding apparatus and said connection for feeding additional chemical are flow communication with a paper machine headbox feed duct downstream of a machine screen.