Hollow tubular filter and manufacturing apparatus

Abstract

Embodiments of the present invention provide a hollow cylindrical filter for removing efficiently foreign substances from fluids. This is performed by forming complicated passages including an axial direction and a radial direction in the filter. The hollow cylindrical filter is formed by winding a metal wire rod in a spiral and multilayered manner. The metal wire rod includes a recess formed throughout the entire length in a longitudinal direction, or recesses repeated along said longitudinal direction. Some wire rod layers extend in an axial direction of the hollow cylindrical filter while the adjacent wire rod layers extend in an intersecting direction, thereby forming a plurality of communication paths for communicating between the overlapping wire rod layers. Additionally, a space is formed between the recess of one wire rod layer and another adjacent wire rod layer, allowing the plurality of communication paths to communicate with each other.

1 . A hollow cylindrical filter formed by winding a metal wire rod in a spiral and multilayered manner, wherein:
 the metal wire rods that configure wire rod layers extend in a direction inclined with respect to an axial direction of the hollow cylindrical filter,   the metal wire rods that configure the adjacent wire rod layers extend in directions intersecting with each other, to form a plurality of communication paths communicating in a direction into which the wire rod layers overlap with each other, and   a space that allows the plurality of communication paths to communicate with each other is formed by a recess formed in the metal wire rod that configures at least one of the wire rod layers, between the metal wire rod that configures one wire rod layer and the metal wire rod that configures another wire rod layer adjacent to the one wire rod layer.   
     
     
         2 . The hollow cylindrical filter according to  claim 1 , wherein the metal wire rod includes the recess formed along a longitudinal direction. 
     
     
         3 . The hollow cylindrical filter according to  claim 1 , wherein the metal wire rod includes the recesses repeated along a longitudinal direction. 
     
     
         4 . The hollow cylindrical filter according to  claim 1 , wherein the metal wire rod includes the recesses repeated in a direction intersecting with a longitudinal direction. 
     
     
         5 . The hollow cylindrical filter according to  claim 1 , wherein the metal wire rod includes thick narrow portions and thin wide portions repeated along a longitudinal direction. 
     
     
         6 . The hollow cylindrical filter according to  claim 1 , wherein a back side of the metal wire rod in which the recess is formed is a flat surface. 
     
     
         7 . The hollow cylindrical filter according to  claim 1 , wherein the metal wire rod is arranged such that the recess faces an upstream side of a fluid to be filtrated. 
     
     
         8 . The hollow cylindrical filter according to  claim 1 , wherein the metal wire rod is arranged such that the recess faces a downstream side of a fluid to be filtrated. 
     
     
         9 . The hollow cylindrical filter according to  claim 1 , wherein the metal wire rod includes a first metal wire rod portion extending in a longitudinal direction, and a second metal wire rod portion arranged in a different position from the first metal wire rod portion in the longitudinal direction and having a different external shape, the recess is formed in at least one of the metal wire rod portions. 
     
     
         10 . An apparatus for manufacturing the hollow cylindrical filter according to  claim 9 , the apparatus comprising:
 a rolling device including a pair of rolling rollers arranged to face each other, and configured to sandwich a metal wire and form the metal wire rod having a predetermined cross-sectional shape; and   a winding device configured to wind the metal wire rod formed by the rolling device around a core rod to form a hollow cylindrical body, wherein   the pair of rolling rollers includes a first metal wire rod forming portion that forms the first metal wire rod portion and a second metal wire rod forming portion that forms the second metal wire rod portion in different positions in the axial direction, and   the rolling device includes guide means that moves forward and backward along the axial direction of the pair of rolling rollers to guide the metal wire to the first metal wire rod forming portion or the second metal wire rod forming portion.