Pressing apparatus having semipermeable membrane

An apparatus for processing a continuous web having a first side and a second side, comprising:

• a pressing assembly defining a chamber, said chamber having an inlet and an outlet;
• a first pressure source fluidly coupled to said chamber to pressurize said chamber with a fluid;
• a membrane positioned adjacent said first side of said continuous web, said continuous web and said membrane entering said chamber at said inlet and exiting said chamber at said outlet, said membrane being a semi-permeable membrane structured and adapted to have a permeability which permits a limited predetermined flow of said fluid therethrough to said continuous web, said membrane has a permeability greater than zero and less than about five CFM per square foot as measured by TAPPI test method TIP 0404-20;
• a differential pressure source coupled to said chamber to effect a flow of said fluid through said membrane and said continuous web, said membrane structured and adapted for communicating with the pressurized chamber and said differential pressure source to apply a mechanical pressing force to said continuous web.

An apparatus for processing a continuous web having a first side and a second side, comprising:

• a plurality of rollers arranged for cooperative rotation, each of said plurality of rollers having a first circular end, a second circular end and a cylindrical middle surface, said plurality of rollers including a plurality of main rollers and a plurality of cap rollers positioned to define a plurality of inlet roller nips and a plurality of outlet roller nips, and a portion of said plurality of rollers having at least one void formed in said cylindrical middle surface;
• a first and second sealing panel for engaging said first and second circular ends of each of said plurality of rollers, said first and second sealing panels and said plurality of rollers defining a plurality of chambers;
• at least a first pressure source fluidly coupled to each of said plurality of chambers to pressurize said plurality of chambers;
• and
• at least one semi-permeable membrane structured and adapted to engage a portion of said plurality of inlet roller nips, to hydraulically communicate with said cylindrical middle surface of a portion of said plurality of main rollers and to engage a portion of said plurality of outlet roller nips to define a plurality of expanded nips, said membrane has a permeability greater than zero and less than about five CFM per square foot as measured by TAPPI test method TIP 0404-20.

An apparatus for processing a continuous web having a first side and a second side, comprising:

• a plurality of rollers arranged for cooperative rotation, each of said plurality of rollers having a first circular end, a second circular end and a cylindrical middle surface, said plurality of rollers positioned to define a corresponding plurality of nips, said continuous web being processed through at least two of said plurality of nips, and at least a first roller of said plurality of rollers having at least one void formed in said cylindrical middle surface;
• a first and second sealing panel for engaging said first and second circular ends of each of said plurality of rollers, said first and second sealing panels and said plurality of rollers defining a chamber;
• a first pressure source fluidly coupled to said chamber to pressurize said chamber to a pressure of at least about 30 pounds per square inch;
• and
• a membrane positioned adjacent said first side of said continuous web to separate said continuous web from direct communication with said chamber, said membrane being structured and adapted to be a semi-permeable membrane having a permeability which permits a limited predetermined fluid flow therethrough to said continuous web and being structured and adapted for communicating with the pressurized chamber and said at least one void to apply a mechanical pressing force to said continuous web, said membrane being structured and adapted to have a permeability such that said membrane is thereby configured to simultaneously effect a given fluid flow through said continuous web and a mechanical pressure thereupon.

An apparatus for processing a continuous web having a first side and a second side, comprising:

• a pressing assembly defining a chamber, said chamber having an inlet and an outlet;
• a first pressure source fluidly coupled to said chamber to pressurize said chamber with a fluid to a pressure of at least about 30 pounds per square inch;
• a membrane positioned adjacent said first side of said continuous web, said continuous web and said membrane entering said chamber at said inlet and exiting said chamber at said outlet, said membrane being semi-permeable;
• a differential pressure source coupled to said chamber to effect a flow of said fluid through said membrane and said continuous web, said membrane being structured and adapted to have a permeability such that said membrane is thereby configured for simultaneously effecting a given fluid flow through said continuous web and for communicating with the pressurized chamber and said differential pressure source to apply a mechanical pressing force to said continuous web.

An apparatus for processing a continuous web having a first side and a second side, comprising:

• a plurality of rollers arranged for cooperative rotation, each of said plurality of rollers having a first circular end, a second circular end and a cylindrical middle surface, said plurality of rollers including a plurality of main rollers and a plurality of cap rollers positioned to define a plurality of inlet roller nips and a plurality of outlet roller nips, and a portion of said plurality of rollers having at least one void formed in said cylindrical middle surface;
• a first and second sealing panel for engaging said first and second circular ends of each of said plurality of rollers, said first and second sealing panels and said plurality of rollers defining a plurality of chambers;
• at least a first pressure source fluidly coupled to each of said plurality of chambers to pressurize said plurality of chambers to a pressure of at least about 30 pounds per square inch;
• and
• at least one semi-permeable membrane structured and adapted to engage a portion of said plurality of inlet roller nips, to hydraulically communicate with said cylindrical middle surface of a portion of said plurality of main rollers and to engage a portion of said plurality of outlet roller nips to define a plurality of expanded nips, each said membrane being structured and adapted to have a permeability such that said each said membrane is thereby configured to simultaneously effect a given fluid flow through said continuous web and effect a mechanical pressure thereupon.