Pulp dewatering clothing for a pulp dewatering machine

Abstract

A pulp dewatering fabric includes a pulp-side first woven fabric layer for receiving the cellulose pulp material to be dewatered and a running-side second woven fabric layer. The first woven fabric layer is formed with first longitudinal threads which run in a belt longitudinal direction and first transverse threads which run in a belt transverse direction. The second woven fabric layer is formed with second longitudinal threads which run in the belt longitudinal direction and second transverse threads which run in the belt transverse direction. The first woven fabric layer and the second woven fabric layer are joined to one another by connecting threads. Second floats are formed by the second longitudinal threads or the second transverse threads on a running-side outer side.

What is claimed is: 
     
         1 . A pulp dewatering clothing for a pulp dewatering machine, the pulp dewatering clothing comprising:
 a plurality of binding threads;   a pulp-side first woven fabric layer for receiving a cellulose pulp material to be dewatered, said pulp-side first woven fabric layer being formed with a plurality of first longitudinal threads which progress substantially in a longitudinal direction of the clothing and a plurality of first cross threads which progress substantially in a transverse direction of the clothing, wherein a plurality of first floats are formed by one of said first longitudinal threads and said first cross threads on a pulp-side outer side of the clothing; and   a machine-side second woven fabric layer formed with a plurality of second longitudinal threads which progress substantially in said longitudinal direction of the clothing and a plurality of second cross threads which progress substantially in said transverse direction of the clothing, said first woven fabric layer and said second woven fabric layer being joined to one another by said binding threads, wherein a plurality of second floats are formed by one of said second longitudinal threads or said second cross threads on a machine-side outer side of the clothing and at least one of a maximum float length and a mean float length of said second floats is greater than at least one of a maximum float length and a mean float length of said first floats.   
     
     
         2 . The pulp dewatering clothing according to  claim 1 , wherein at least one of said second floats have a float length in a range of between approximately 2 and 11, and said first floats have a float length of a maximum of 4. 
     
     
         3 . The pulp dewatering clothing according to  claim 2 , wherein said float length of said second floats is in a range of between approximately 3 to 9. 
     
     
         4 . The pulp dewatering clothing according to  claim 3 , wherein said float length of said second floats is approximately 7. 
     
     
         5 . The pulp dewatering clothing according to  claim 1 , wherein said first woven fabric layer is one of a plain weave fabric and a rib weave fabric. 
     
     
         6 . The pulp dewatering clothing according to  claim 1 , wherein said longitudinal threads and said cross threads forming said first floats and said second floats have a thread type which is the same. 
     
     
         7 . The pulp dewatering clothing according to  claim 1 , wherein said longitudinal threads and said cross threads forming said first floats and said second floats have a thread type which is the different. 
     
     
         8 . The pulp dewatering clothing according to  claim 1 , wherein at least one of said first longitudinal threads and said binding threads progressing in said longitudinal direction in said first woven fabric layer are offset relative to at least one of said second longitudinal threads and said binding threads progressing in said transverse direction in said second woven fabric layer. 
     
     
         9 . The pulp dewatering clothing according to  claim 1 , wherein one type of thread of said longitudinal threads and said cross threads is provided by warp threads and another type of threads of said longitudinal threads and said cross threads is provided by weft threads, said warp threads of said first woven fabric layer and said warp threads of said second fabric layer being offset relative to each other in a weft direction. 
     
     
         10 . The pulp dewatering clothing according to  claim 1 , wherein said binding threads include binding thread pairs consisting always of two of said binding threads adjacently positioned and assigned to each other as pairs, said pairs continuing a weave structure of said first woven fabric layer. 
     
     
         11 . The pulp dewatering clothing according to  claim 1 , said plurality of binding threads including binding threads not continuing a weave structure of said first woven fabric layer and not tying off with said first longitudinal threads or said first cross threads. 
     
     
         12 . The pulp dewatering clothing according to  claim 1 , wherein the clothing is configured to handle a tension of approximately 3 to 100 kilonewtons per meter (kN/m) 
     
     
         13 . The pulp dewatering clothing according to  claim 12 , wherein the clothing is configured to handle a tension of approximately 8 to 80 kN/m. 
     
     
         14 . The pulp dewatering clothing according to  claim 13 , wherein the clothing is configured to handle a tension of approximately 5 to 50 kN/m. 
     
     
         15 . A pulp dewatering machine, comprising:
 at least one pulp dewatering clothing, comprising:   a plurality of binding threads;   a pulp-side first woven fabric layer for receiving a cellulose pulp material to be dewatered, said pulp-side first woven fabric layer being formed with a plurality of first longitudinal threads which progress substantially in a longitudinal direction of the clothing and a plurality of first cross threads which progress substantially in a transverse direction of the clothing, wherein a plurality of first floats are formed by one of said first longitudinal threads and said first cross threads on a pulp-side outer side of the clothing; and   a machine-side second woven fabric layer formed with a plurality of second longitudinal threads which progress substantially in said longitudinal direction of the clothing and a plurality of second cross threads which progress substantially in said transverse direction of the clothing, said first woven fabric layer and said second woven fabric layer being joined to one another by said binding threads, wherein a plurality of second floats are formed by one of said second longitudinal threads or said second cross threads on a machine-side outer side of the clothing and at least one of a maximum float length and a mean float length of said second floats is greater than at least one of a maximum float length and a mean float length of said first floats.   
     
     
         16 . The pulp dewatering machine according to  claim 15 , said at least one pulp dewatering clothing being two pulp dewatering clothings guided around at least one turn roller in a twin-wire zone of the pulp dewatering machine. 
     
     
         17 . The pulp dewatering machine according to  claim 15 , wherein the pulp dewatering machine is not equipped with a press nip. 
     
     
         18 . The pulp dewatering machine according to  claim 16 , including a pre-dewatering zone located before said twin-wire zone and through which said pulp dewatering clothing is routed. 
     
     
         19 . The pulp dewatering machine according to  claim 18 , wherein said at least one turn roller includes a first turn roller and an additional turn roller and in said twin-wire zone both of said two pulp dewatering clothings move first around said first turn roller having a first roll turning axis located substantially above said pre-dewatering zone, and subsequently move around said additional turn roller having another roll turning axis positioned above said first roll turning axis. 
     
     
         20 . A method of using a pulp dewatering clothing, the method comprising the steps of:
 providing at least one pulp dewatering clothing, comprising:
 a plurality of binding threads; 
 a pulp-side first woven fabric layer for receiving a cellulose pulp material to be dewatered, said pulp-side first woven fabric layer being formed with a plurality of first longitudinal threads which progress substantially in a longitudinal direction of the clothing and a plurality of first cross threads which progress substantially in a transverse direction of the clothing, wherein a plurality of first floats are formed by one of said first longitudinal threads and said first cross threads on a pulp-side outer side of the clothing; and 
 a machine-side second woven fabric layer formed with a plurality of second longitudinal threads which progress substantially in said longitudinal direction of the clothing and a plurality of second cross threads which progress substantially in said transverse direction of the clothing, said first woven fabric layer and said second woven fabric layer being joined to one another by said binding threads, wherein a plurality of second floats are formed by one of said second longitudinal threads or said second cross threads on a machine-side outer side of the clothing and at least one of a maximum float length and a mean float length of said second floats is greater than at least one of a maximum float length and a mean float length of said first floats; and 
   routing said at least one pulp dewatering clothing through a pre-dewatering zone located before a twin-wire zone in a pulp dewatering machine to dewater the pulp suspension with said at least one pulp dewatering clothing.