Velocity induced drainage method and unit
AssigneesThermo Fibertek Inc., Smurfit Carton Y Papel de Mexico
InventorsLuis Fernando Cabrera y Lopez Caram, Jeffrey P. Bachand
Life of this patent
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Abstract
A drainage device and method which provides for drainage from paper or pulp stock on a fabric in a sheet or mat making machine which includes a primary blade and trail blade with a gap therebetween for drainage wherein the size of the gap controls drainage and the primary blade is so configured so as to force a portion of the drained liquid through the fabric to create paper stock activity and disbursement while minimizing turbulence and maintaining laminar flow in the machine direction along with providing reinforcement of CD shear.
Claims38
A drainage device for use in a pulp or papermaking machine for drainage of liquid from pulp or paper stock contained on a fabric which passes over said device, comprising:
- a blade arrangement comprising a primary blade and a trail blade;
- a gap formed between the primary blade and a trail blade to allow drainage of liquid therethrough;
- said primary blade having a leading edge support surface adjacent the fabric for support thereof and a trailing surface that diverges downward from said support surface away from the fabric on the support surface so that a space is formed between said fabric and said trailing surface;
- said trail blade having a leading edge support surface for the fabric;
- means for maintaining controlled drainage from the paper stock by controlling flow of entrained liquid across the gap whilst completely filling the space between the fabric and trailing surface with entrained liquid so as to allow a portion thereof to be forced back through the fabric;
- and
- said trailing surface of said primary blade being so formed with raised protuberances and valleys so as to force a portion of entrained liquid back through the fabric so as to create activity in the stock to enhance stock distribution.
A drainage device for use in a pulp or papermaking machine for drainage of liquid from pulp or paper stock contained on a fabric which passes over said device, comprising:
- a blade arrangement comprising a primary blade and a trail blade;
- a gap formed between the primary blade and a trail blade to allow drainage of liquid therethrough;
- said primary blade having a leading edge support surface adjacent the fabric for support thereof and a trailing surface that diverges downward from said support surface away from the fabric on the support surface so that a space is formed between said fabric and said trailing surface;
- said trail blade having a leading edge support surface for the fabric;
- means for maintaining said space and said gap filled with liquid by controlling flow of entrained liquid across the gap;
- and
- said primary blade shape having raised protuberances and valleys which force some or all of the liquid drained back through the fabric to facilitate stock distribution and activity in the paper stock while facilitating laminar flow in the machine direction.
A method for draining liquid from paper stock contained on a fabric in a pulp or papermaking machine comprising the following steps:
- providing a drainage device having a primary blade and a trail blade with a gap therebetween for drainage;
- providing said drainage device for use in a pulp or papermaking machine for drainage of liquid from pulp or paper stock contained on a fabric which passes over said device;
- forming a space between the primary blade and the fabric passing thereover;
- adjusting the size of the gap to control the desired amount of drainage whilst completely filling the space between the fabric and trailing surface with entrained liquid so as to allow a portion thereof to be forced back through the fabric;
- and
- providing said trailing surface of said primary blade with raised protuberances and valleys so as to force a portion of the entrained liquid back through the fabric so as to cause activity in the stock to enhance stock distribution.
Dependencies are inferred from the claim text.