Process for making a shaped fibrous article by a vacuum forming process and the shaped fibrous article made thereby

• US 3,968,004 A
• Filed: 11/21/1973
• Issued: 07/06/1976
• Est. Priority Date: 11/21/1973
• Status: Expired due to Term

• Current Assignee: Pittsburgh Corning Corporation (Nouryon BV)
• Original Assignee: Pittsburgh Corning Corporation (Nouryon BV)
• Inventors: Weaver, Harold Lloyd, Coffey, Fred Simms, Johnson, Howard Beattie
• Primary Examiner(s): Lindsay, Jr., Robert L.
• Assistant Examiner(s): Chin, Peter
• Application Number:
  US05/417,976
• Time in Patent Office: 958 Days
• Field of Search: 162/152, 162/218, 162/228, 162/384, 162/382, 162/389, 162/119, 162/181 D, 162/221, 162/222, 162/387, 162/266, 264/108, 264/114, 425/84, 425/85, 425/86, 425/87
• US Class Current: 162/152
• CPC Class Codes: D21J 7/00 Manufacture of hollow articles from fibre suspensions or papier-mâché by deposition of fibres in or on a wire-net mould

Abstract

A dilute slurry that includes mineral wool fibers, a clay binder, other binders and a flocculent is introduced into a forming tank at several elevations and with sufficient velocity to circulate toroidally therein. A mandrel having the desired configuration of one surface of the shaped article is lowered into the forming tank and rotated at a preselected speed. Vacuum is applied to the rotating mandrel and a substantially uniform layer of solids is deposited on the outer surface of the mandrel while the filtrate is withdrawn through an internal portion of the mandrel and conveyed to a filtrate recovery tank. After a layer of a preselected thickness is deposited on the outer surface of the mandrel, the mandrel is removed from the forming tank and vacuum is maintained on the mandrel to reduce the water content of the accreted fibers to between about 40 to 65% by weight water. Thereafter, while on the mandrel, the accreted fiber-shaped article is trimmed to provide an outer surface of a desired configuration. The trimmed article is thereafter sprayed with a coating material while vacuum is maintained on the mandrel so that the coating material penetrates the surface of the shaped article. The shaped article is thereafter removed from the mandrel and trimmed to provide a fibrous shaped article having a desired configuration and thickness.

Claims

1. A process for making a fibrous shaped article comprising,

introducing a dilute aqueous slurry containing mineral wool fibers, a clay binder and other binders into a forming tank tangentially to the direction of circulation to toroidally circulate said slurry in said forming tank to maintain said solids substantially uniformly distributed therein, said slurry having between about 1 and 5% solids by weight,

positioning a foraminous member in said circulating slurry in said forming tank so that said foraminous member is submerged in said slurry,

applying a suction to an internal portion of said foraminous member and accreting a substantially uniform layer of said solids in said slurry on the outer surface of said foraminous member,

maintaining said foraminous member submerged in said slurry while accreting said substantially uniform layer of said solids thereon,

trimming the outer surface of said layer of accreted solids while said layer of accreted solids is on said foraminous member to form a shaped article having an inner surface with the configuration of the outer surface of said foraminous member and an outer surface of a preselected configuration,

thereafter removing said shaped article from said foraminous member, and

drying said shaped article to remove substantially all of the liquid in the shaped article of accreted solids.

2. A process for making a fibrous shaped article as set forth in claim 1 in which,

said foraminous member comprises a mandrel having a cylindrical outer surface,

positioning said mandrel vertically in said slurry in said forming tank while accreting solids thereon to form a substantially cylindrically shaped article of accreted solids.

3. A process for making a fibrous shaped article as set forth in claim 2 which includes,

rotating said mandrel in said forming tank while accreting said solids thereon.

4. A process for making a fibrous shaped article as set forth in claim 3 which includes,

rotating said mandrel in a direction opposite to the direction of circulation of said slurry.

5. A process for making a fibrous shaped article as set forth in claim 1 which includes,

removing said foraminous member from said forming tank and maintaining suction on said foraminous member to reduce the water content of said accreted solids to between about 40 to 65% water by weight.

6. A process for making a fibrous shaped article as set forth in claim 5 which includes,

trimming the outer surface of said accreted solids on said foraminous member while said accreted solids contain between about 40 and 65% liquid by weight.

7. A process for making a fibrous shaped article as set forth in claim 1 which includes,

introducing said slurry at a plurality of different elevations into said forming tank to maintain said solids in said slurry uniformly distributed therein.

8. A process for making a fibrous shaped article as set forth in claim 1 which includes,

withdrawing the filtrate formed by the accretion of said solids on said foraminous member through an internal portion of said foraminous member, said filtrate containing between about 1 and 3% solids by weight,

recirculating said filtrate to a slurry preparation tank,

adding mineral wool fibers and binders to the filtrate to form said dilute slurry.

9. A process for making a fibrous shaped article as set forth in claim 2 which includes,

positioning said mandrel with said layer of accreted solids thereon in abutting relation with an endless saw blade,

moving said saw blade relative to said layer of accreted solids while rotating said mandrel, and

trimming the layer of said accreted solids with said saw blade to form a shaped article having a generally cylindrical outer surface.

10. A process for making a fibrous shaped article as set forth in claim 9 which includes,

maintaining a suction on said mandrel while trimming said layer of accreted solids with said saw blade,

thereafter terminating the suction on said mandrel and trimming said layer of said accreted solids a second time with said saw blade to form a shaped article having a generally cylindrical outer surface.

11. A process for making a fibrous shaped article as set forth in claim 1 which includes,

spraying a coating material on the outer surface of said shaped article while said shaped article remains on said foraminous member,

applying suction to said foraminous member while spraying said coating material on the outer surface of said shaped article so that the coating material penetrates the outer surface of said shaped article.