Method and device in the regulation of a headbox

A method for regulating a total pulp flow from a headbox, comprising a pulp inlet header, a discharge duct and conduit means for passing the total headbox pulp flow from said inlet header to said discharge duct, said conduit means including a plurality of conduits, said total headbox pulp flow comprising at least one component flow, the method comprising the steps of:

• forming said at least one component flow from component subflows arranged at different locations in a direction transverse to a direction of flow of said at least one component flow,
• forming each of said component subflows from at least first and second subcomponent flows,
• directing each of said second subcomponent flows from said inlet header into a respective one of said conduits,
• introducing each of said first subcomponent flows into one of said second subcomponent flows at a point within one of said conduits at a certain mixing ratio, said introducing step comprising the steps of passing at least one of said first subcomponent flows into a mixing chamber in at least one of said conduits, coupling said mixing chamber to said inlet header, and passing said subflow constituting a combination of said at least one of said first subcomponent flows and one of said second subcomponent flows from said mixing chamber into a first duct portion of said at least one of said conduits having a sectional flow area smaller than the sectional flow area of said mixing chamber, and
• regulating the concentration of each of said subflows by adjusting the flow rates of said first subcomponent flow and said second subcomponent flow which constitute said subflow relative to one another.

A method for regulating a total pulp flow from a headbox, said headbox comprising a pulp inlet header, a discharge duct, and conduit means for passing the total headbox pulp flow from said inlet header to said discharge duct, said conduit means including a plurality of conduits, said total headbox pulp flow comprising a plurality of component flows, the method comprising the steps of:

• forming each of said plurality of component flows from component subflows arranged at different locations in a direction transverse to a direction of flow of said component flow,
• forming a plurality of said component subflows from at least first and second subcomponent flows,
• directing each of said second subcomponent flows from said inlet header into a respective one of said conduits,
• introducing said first subcomponent flows into said second subcomponent flows within said conduits, said introducing step comprising the steps of arranging mixing chambers in said conduits, passing each of said second subcomponent flows through a respective pipe arranged in one of said mixing chambers, passing one of said first subcomponent flows annularly from around said pipe into an end of each of said mixing chambers, and
• regulating the concentration of each of said subflows by adjusting the flow rates of said first subcomponent flow and said second subcomponent flow, which constitute said subflow, relative to one another.

A method for regulating a total pulp flow from a headbox, comprising a pulp inlet header, a discharge duct, and conduit means for passing the total headbox pulp flow from said inlet header to said discharge duct, said conduit means including a plurality of conduits, said total headbox pulp flow comprising a plurality of component flows, the method comprising the steps of:

• forming each of said plurality of component flows from component subflows arranged at different locations in a direction transverse to a direction of flow of said component flow,
• forming a plurality of said component subflows from at least first and second subcomponent flows,
• directing each of said second subcomponent flows from said inlet header into a respective one of said conduits,
• introducing said first subcomponent flows into said second subcomponent flows within said conduits, said introducing step comprising the steps of passing one of said first subcomponent flows into a mixing chamber in one of said conduits, coupling said mixing chamber to said inlet header, and passing said subflow formed in said mixing chamber from said mixing chamber into a first duct portion of said one of said conduits having a sectional flow area smaller than the sectional flow area of said mixing chamber, and
• regulating the concentration of each of said subflows by adjusting the flow rates of said first subcomponent flow and said second subcomponent flow which constitute said subflow relative to one another.

In a headbox comprising a pulp inlet header, a discharge duct and conduit means for passing a total headbox pulp flow from said inlet header to said discharge duct, said conduit means including a plurality of conduits, said total headbox pulp flow comprising at least one component flow having component subflows in a transverse direction of said headbox, the improvement comprising;

• a device for regulating the flow of said at least one component flow through said conduit means, said device comprising
• means for forming component subflows of said at least one component flow arranged at different locations in a direction transverse to a direction of flow of said at least one component flow, each of said component subflows being formed from at least first and second subcomponent flows,
• means for regulating the flow of each of said first subcomponent flows relative to the flow of a respective one of said second subcomponent flows to thereby regulate the concentration of said component subflows and thus said at least one component flow so as to adjust the grammage of a web formed from said total headbox pulp flow to a desired level in the transverse direction, said regulation means comprising;
• means for passing each of said second subcomponent flow from said inlet header to a respective one of said conduits,
• additional-flow duct means for directing each of said first subcomponent flows into one of said second subcomponent flows within one of said conduits, said additional-flow duct means communicating with a respective one of said conduits such that said first subcomponent flows are carried into different positions in the transverse direction of said at least one component flow,
• means for regulating the flow of said first subcomponent flows through said additional-flow duct means, and
• means defining a mixing chamber arranged in each of said conduits, said additional-flow duct means being connected to said mixing chambers.

In a headbox comprising a pulp inlet header, a discharge duct and conduit means for passing a total headbox pulp flow from said inlet header to said discharge duct, said conduit means including a plurality of conduits, said total headbox pulp flow comprising a plurality of component flows having component subflows in a transverse direction, the improvement comprising;

• a device for regulating the flow of said component flows through said conduit means, said device comprising
• means for forming component subflows of each of said component flows arranged at different locations in a direction transverse to a direction of flow of said component flow, a plurality of said component subflows being formed from at least first and second subcomponent flows,
• means for regulating the concentration of each of said plurality of said component subflows formed from said first and second component subflows and thus said component flows so as to adjust the grammage of a web formed from said total headbox pulp flow to a desired level in the transverse direction, said regulating means comprising;
• means for passing each of said second subcomponent flows from said inlet header to a respective one of said conduits,
• additional-flow duct means for directing said first subcomponent flows into said second subcomponent flows within said conduits, said additional-flow duct means communicating with said conduits,
• means for regulating the flow of said first subcomponent flows through said additional-flow duct means, and
• means defining a mixing chamber in each of said conduits, said additional-flow duct means being connected to said mixing chambers.