Filter cartridge assembly and method of manufacture

Abstract

An apparatus for filtering well fluids and method of manufacture is disclosed. The apparatus includes an inner support, a filter helically wrapped around the inner support, and an outer support helically wrapped around the filter. The outer support frictionally engages the filter and encloses the filter between the inner and outer supports. The filter may have offset longitudinal edges which overlap. The filter may be held in place by friction with both the inner and outer supports. The method of manufacturing the apparatus includes helically wrapping a filter medium together with a metal sheet onto an inner support, the metal sheet frictionally engaging the filter medium to retain the filter medium between the metal sheet and the inner support.

1 . An apparatus for filtering well fluids, the apparatus comprising: 
 an inner support;    a filter helically wrapped around the inner support;    an outer support helically wrapped around the filter enclosing the filter between the inner and outer supports;    wherein the outer support frictionally engages the filter.    
   
   
       2 . The apparatus of  claim 1  wherein the outer support is cold-rolled over the filter.  
   
   
       3 . The apparatus of  claim 1  wherein the filter has longitudinal edges which overlap.  
   
   
       4 . The apparatus of  claim 3  wherein the overlapping edges are frictionally engaged holding the edges in place.  
   
   
       5 . The apparatus of  claim 3  wherein the overlapping edges are not welded.  
   
   
       6 . The apparatus of  claim 3  wherein the filter comprises a plurality of layers.  
   
   
       7 . The apparatus of  claim 6  wherein each of the plurality of layers is offset from the other layers such that the overlapping longitudinal edges do not align.  
   
   
       8 . The apparatus of  claim 6  wherein at least one of the filter layers includes a plurality of filter sheets.  
   
   
       9 . The apparatus of  claim 8  wherein a seam exists between two adjoining filter sheets within a filter layer, and the seam is substantially offset from the seams in either of the adjacent filter layers.  
   
   
       10 . The apparatus of  claim 8  wherein a gap exists between two adjoining filter sheets within a filter layer, and the gap is substantially offset from gaps in either of the adjacent filter layers.  
   
   
       11 . The apparatus of  claim 1  wherein the filter is stabilized and held in place by frictionally engaging the inner and outer supports.  
   
   
       12 . The apparatus of  claim 1  wherein the outer support edges are welded.  
   
   
       13 . The apparatus of  claim 1  wherein inner and outer supports with filter therebetween are placed over a base pipe and then welded to the base pipe to create a cartridge.  
   
   
       14 . The apparatus of  claim 13  wherein the cartridge has ends which are left unfinished.  
   
   
       15 . The apparatus of  claim 13  wherein the cartridge is cut to a predetermined length.  
   
   
       16 . The apparatus of  claim 1  comprising a tubular well filter cartridge, the tubular well filter cartridge having a pre-determined outer diameter wherein the outer support is helically wrapped around the filter to the pre-determined outer diameter with the outer support frictionally engaging the filter and enclosing the filter between the inner and outer supports.  
   
   
       17 . The apparatus of  claim 1  for filtering well fluids, the inner and outer supports and filter being permeable to the well fluids.  
   
   
       18 . An apparatus for filtering well fluids, the apparatus comprising: 
 an inner support;    a filter helically wrapped around the inner support; and    an outer support helically wrapped around the filter enclosing the filter between the inner and outer supports;    wherein each helical wrap of the filter includes a plurality of filter layers, each layer being offset from and overlapping an adjacent layer.    
   
   
       19 . A well filter for filtering a radial flow of well fluids, the apparatus comprising: 
 a filter medium/metal sheet combination formed by laying a filter medium onto a metal sheet with the filter medium being unconnected to the metal sheet; and    with the filter medium being together on the metal sheet, the filter medium/metal sheet combination being helically wrapped onto a perforated tubular member;    the metal sheet frictionally engaging the filter medium to retain the filter medium between the metal sheet and the perforated tubular member.