Woven loop press base fabric having high density top layer

Abstract

A papermaker's fabric having a system of primary machine direction yarns which form seaming loops at each end of the fabric and a system of secondary machine direction yarns. A system of cross-machine direction yarns are interwoven with the primary and secondary systems of machine direction yarns in a weave pattern that provides adjacent balancing yarns that maintain the seam loops in substantially vertical alignment.

What is claimed is:  
     
       1. An improved papermaker's fabric of a type having a system of primary machine direction (MD) yarns which form seaming loops at each end of the fabric, the improvement characterized by: 
       a system of secondary MD yarns that at least equal in number the number of primary MD yarns; and  
       a system of cross-machine direction yarns (CMD) interwoven with the primary and secondary systems of MD yarns in a weave pattern that provides adjacent balancing yarns that maintain the seam loops in substantially vertical alignment.  
     
     
       2. The fabric according to claim  1  wherein the primary MD yarn system includes stacked lower and middle layer MD yarns and the secondary MD yarn system includes a single layer of upper MD yarns. 
     
     
       3. The fabric according to claim  2  wherein the CMD yarn system includes two sub-systems, the first CMD sub-system yarns weaving exclusively with the upper and middle layer MD yarns and the second CMD sub-system yarns weaving exclusively with the middle and lower layer MD yarns. 
     
     
       4. The fabric according to claim  3  wherein each first CMD sub-system yarn weaves in a repeat pattern of over two, under four, over two and under four relative to the upper and middle layer MD yarns. 
     
     
       5. The fabric according to claim  3  wherein each second CMD sub-system yarn weaves in a repeat pattern of over, between, under, between relative to the stacked pairs of middle and lower layer MD yarns. 
     
     
       6. The fabric according to claim  1  wherein the fabric repeats on sixteen CMD yarns. 
     
     
       7. The fabric according to claim  1  wherein the fabric repeats on thirty-two MD yarns. 
     
     
       8. The fabric of claim  1  wherein the fabric is flat woven. 
     
     
       9. The fabric of claim  1  wherein the fabric is endless woven. 
     
     
       10. The fabric of claim  9  wherein the fabric is woven using a two shuttle loom. 
     
     
       11. The fabric of claim  1  wherein batt material is attached thereto. 
     
     
       12. The fabric according to claim  3  wherein the first CMD sub-system yarns weave in repeat pattern of over one, under one with respect to the middle layer MD yarns.