Method for weaving a filter fabric belt for pressure filter apparatus

• US 5,615,713 A
• Filed: 09/29/1995
• Issued: 04/01/1997
• Est. Priority Date: 07/08/1994
• Status: Expired due to Term

• Current Assignee: Flsmidth A/S (Flsmidth & Company A/S)
• Original Assignee: Steve C. Benesi
• Inventors: Benesi, Steve C.
• Primary Examiner(s): Falik, Andy
• Application Number:
  US08/536,652
• Time in Patent Office: 550 Days
• Field of Search: 139/383 R, 139/420 A, 139/383 A, 139/110, 139/97, 34/116, 210/500.1
• US Class Current: 139/97
• CPC Class Codes: D03D 1/0041 Cut or abrasion resistant
• CPC Class Codes: D03D 15/00 Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used
• CPC Class Codes: D03D 15/267 Glass
• CPC Class Codes: D03D 15/283 synthetic polymer-based, e.g. polyamide or polyester fibres cellulose-based artificial fibres D03D15/225
• CPC Class Codes: D03D 15/41 with specific twist
• CPC Class Codes: D03D 15/50 characterised by the properties of the yarns or threads
• CPC Class Codes: D10B 2101/06 Glass
• CPC Class Codes: D10B 2201/02 Cotton
• CPC Class Codes: D10B 2321/022 polypropylene
• CPC Class Codes: D10B 2331/02 polyamides D10B2331/08 takes precedence
• CPC Class Codes: D10B 2331/04 polyesters, e.g. polyethylene terephthalate [PET]
• CPC Class Codes: D10B 2401/021 hydrophobic
• CPC Class Codes: D10B 2401/022 hydrophylic
• CPC Class Codes: D10B 2505/04 Filters
• CPC Class Codes: D21F 1/0027 Screen-cloths
• CPC Class Codes: D21F 1/0036 Multi-layer screen-cloths
• CPC Class Codes: D21F 1/80 using endless screening belts
• CPC Class Codes: D21J 3/00 Manufacture of articles by pressing wet fibre pulp, or papier-mâché, between moulds
• CPC Class Codes: Y10T 442/3065 Including strand which is of specific structural definition
• CPC Class Codes: Y10T 442/3179 Woven fabric is characterized by a particular or differential weave other than fabric in which the strand denier or warp/weft pick count is specified

Abstract

The method of weaving a dimensionally stable fabric filter medium having particular use in a pressure filter apparatus. The fabric is woven with tension on the warp and weft yarns and the woven fabric is heat set outside the weaving loom to create a desired crimp in the warp and weft yarns and thus to produce a dimensionally stable filter medium. The fabric is woven in a pattern and of materials that provide the desired permeability while being capable of capture of the solids in a slurry and permitting the fluids of the slurry to flow through the medium.

Claims

1. A method of forming a belt filter medium by machine weaving a dimensionally stable controlled permeability woven fabric for use as a belt filter medium in a pressure filter machine, said woven fabric having warp yarns in the direction of said machine and weft yarns in a cross direction of said machine and being adapted for repeated use as a belt filter medium in said pressure filter machine, comprising the steps of:

a) in a weaving loom machine establishing a plurality of individual parallel sized warp yarns with the axis of said warp yarns being in the machine direction of said machine, each of said warp yarns having a total density of about 2,000 denier,

b) placing each warp yarn under equal tension in said machine direction with resulting tension on said woven fabric being about 200 to about 5,000 pounds,

c) weaving a plurality of sized weft yarns through said warp yarns with the axis of said weft yarns being in a cross direction of said machine and placing each of said weft yarns under equal tension in said cross machine direction to produce said woven fabric,

d) transporting said woven fabric from said weaving loom while maintaining said woven fabric under tension by uniformly pulling said warp yarns,

e) passing said woven fabric with tensioned warp yarns through a heating means having a temperature range of about 200°

F. to about 400°

F. to heat set and crimp said warp and weft yarns of said woven fabric, the size of said weft yarns and said warp yarns being related to each other to cause said warp yarns and said weft yarns to become crimped during said heat set step to produce said dimensional stability in said woven fabric,

f) maintaining said tension on said woven fabric as said fabric is accumulated as a continuous woven fabric,

g) and forming said woven fabric as a continuous belt filter medium for use in said pressure filter machine by joining the ends of the woven fabric.

2. The method of claim 1 wherein said woven fabric is a twill weave produced by

a) passing each of said warp yarns sequentially over three adjacent weft yarns and then under three adjacent weft yarns and

b) passing adjacent warp yarns under a first of three weft yarns one weft yarn along said plurality of weft yarns and

c) passing the next adjacent warp yarn over the next of three weft yarns in the warp direction.

3. The method of claim 1 wherein said plurality of warp yarns and said plurality of said weft yarns is selected to produce said woven fabric having a thread count of 69 to 71 warp yarns per linear inch and 20 to 40 weft yarns per linear inch of woven fabric.

4. The method of claim 1 wherein said weft yarns are sized for crimp to conform to the size of said warp yarns and wherein said crimp of said weft yarns is formed by said tension on said warp yarns and the amount of said crimp of said weft yarns is determined by the size and formation of said weft yarns, said crimp being adapted to control movement of said warp yarns with respect to said weft yarns.

5. The method of claim 4 wherein said tension on said warp yarns produces a resulting tension of about 200 to about 5000 pounds on said woven fabric during said passing of said woven fabric through said heating means.

6. The method of claim 1 wherein said woven fabric belt filter medium is produced by

a) pulling two untwisted 1500 denier yarns through the same harness eye of said weaving loom machine to produce each warp yarn with about 120 to 140 ends per inch across said woven fabric,

b) and weaving through said warp yarns a 15 mil ±

0.002 mil monofilament weft yarn

c) whereby said woven fabric having about 22 to 28 picks per inch in said machine direction is produced.

7. The method of claim 1 wherein

a) each warp yarn includes two untwisted 1500 denier yarns pulled through the same harness eye to produce about 120 to 140 ends per inch across said woven fabric

b) weaving through said warp yarns a 19 to 20.5 mil monofilament weft yarn and

c) whereby said woven fabric having 19.5 to 24 picks per inch in said machine direction is produced.

8. The method of claim 4 wherein said crimp in said warp yarns produced by said tension in said weft and warp yarns and said heat setting is less than the crimp in said weft yarns.