Method of forming a semipermeable membrane with intercommunicating pores for a pressing apparatus
AssigneeVoith Sulzer Papiertechnik Patent GmbH
InventorDavid A. Beck
Life of this patent
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Abstract
A unitary membrane for use in a pressing apparatus includes a pair of longitudinal edge portions and a semipermeable portion having a plurality of intercommunicating pores. The semipermeable portion is positioned between the pair of longitudinal edge portions. Wherein the unitary membrane includes a formed fabric and has a thickness less than about 0.1 inches. The semipermeable portion 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 method of making the unitary membrane includes the steps of providing a carrier fabric which is very permeable and forming a plurality of intercommunicating pores in the carrier fabric.
Claims8
A method of making a unitary membrane for use in a pressing apparatus, comprising the steps of:
- providing a carrier fabric which is very permeable;
- and
- forming a plurality of intercommunicating pores in said carrier fabric, said forming step further comprising the steps of:
- blending heat fusible and non-heat fusible fibers;
- needling the blend of fibers into said carrier fabric;
- and
- applying heat to melt said heat fusible fibers, which leave voids in the form of intercommunicating pores.
A method of making a unitary membrane for use in an air pressing apparatus, comprising the steps of:
- providing a carrier fabric which is very permeable;
- and
- forming a plurality of intercommunicating pores in said carrier fabric and reducing the permeability of said carrier fabric, and thereby creating a permeable membrane having a total permeability greater than zero and less than about five CFM per square foot as measured by TAPPI Test Method TIP 0404-20;
- wherein said forming step comprises the steps of:
- forming a resistance layer;
- and
- forming a fluid distribution layer.
A method of making a unitary membrane for use in an air pressing apparatus, comprising the steps of:
- providing a carrier fabric which is very permeable;
- and
- forming a plurality of intercommunicating pores in said carrier fabric and reducing the permeability of said carrier fabric, and thereby creating a semipermeable membrane having a total permeability greater than zero and less than about five CFM per square foot as measured by TAPPI Test Method TIP 0404-20;
- wherein said forming step further comprises the step of successively applying a coating to said carrier fabric until the desired permeability is reached.
A method of making a unitary membrane for use in a pressing apparatus, comprising the steps of:
- providing a carrier fabric which is very permeable;
- and
- forming a plurality of intercommunicating pores in said carrier fabric to thereby create a semipermeable membrane having a foam structure, said forming including successively applying a coating to said carrier fabric and entraining air into said coating to adjust said permeability, until the desired permeability is reached.
Dependencies are inferred from the claim text.