Method and apparatus for making a filter element

Abstract

There is disclosed a method for making a filter element comprising the steps of: advancing two or more sheets of filtering material in a longitudinal direction; separating the two or more sheets of longitudinally advancing filtering material; gathering the separated sheets of longitudinally advancing filtering material to form a partially gathered rod of filtering material having a longitudinally extending recess; inserting an additive release vessel into the longitudinally extending recess; gathering the filtering material around the additive release vessel to close the recess and thereby form a rod comprising a longitudinally extending core of filtering material and one or more additive release vessels.

1 - 33 . (canceled) 
     
     
         34 . A method for making a filter element comprising the steps of:
 advancing two or more sheets of filtering material in a longitudinal direction;   separating the two or more sheets of longitudinally advancing filtering material; gathering the separated sheets of longitudinally advancing filtering material to form a partially gathered rod of filtering material having a longitudinally extending recess;   inserting an additive release vessel into the longitudinally extending recess;   gathering the filtering material around the additive release vessel to close the recess and thereby form a rod comprising a longitudinally extending core of filtering material and one or more additive release vessels.   
     
     
         35 . The method according to  claim 34 , wherein the two or more sheets of longitudinally advancing filtering material are separated by a separator; and/or wherein the gathering of the separated two or more sheets of longitudinally advancing filtering material comprises drawing the separated two or more sheets of longitudinally advancing filtering material into a gathering chamber. 
     
     
         36 . The method according to  claim 35 , wherein the separator is coupled to the gathering chamber such that the two or more sheets of longitudinally advancing filtering material are separated before entering the gathering chamber, and the separator prevents complete gathering of the two or more sheets of longitudinally advancing filtering material to thereby form a longitudinally extending recess in the partially gathered filtering material. 
     
     
         37 . The method according to  claim 35 , wherein the gathering chamber comprises an inlet for receiving the separated sheets of filtering material and an outlet for the partially gathered filtering material to exit, and wherein the gathering chamber is tapered longitudinally away from the inlet; and/or wherein the separator is longitudinally tapered and/or extends into and along at least part of the length of the gathering chamber; and/or wherein the separator is tapered in the same direction as the gathering chamber. 
     
     
         38 . The method according to  claim 36 , wherein the separated two or more longitudinally advancing sheets of filtering material are drawn into a preliminary chamber before entering the gathering chamber; for example wherein the preliminary chamber comprises an inlet and an outlet, wherein the outlet of the preliminary chamber is joined to the inlet of the gathering chamber, and wherein the separator extends into and along at least part of the length of the preliminary chamber. 
     
     
         39 . The method according to  claim 34 , wherein the additive release vessel is inserted into the longitudinally extending recess by an additive release vessel inserter; for example wherein the additive release vessel inserter comprises a rotating drum or wheel. 
     
     
         40 . The method according to  claim 34 , wherein the two or more sheets of filtering material are embossed; and/or wherein the filtering material comprises a non-woven material; and/or wherein the filtering material comprises paper; and/or wherein the two or more sheets of longitudinally advancing filtering material comprise 2, 3 or 4 sheets of longitudinally advancing filtering material. 
     
     
         41 . The method according to  claim 34 , comprising a step of cutting the rod to form a filter element comprising a longitudinally extending core of filtering material and one or more additive release vessels. 
     
     
         42 . A filter element comprising a longitudinally extending core of filtering material and an additive release vessel enclosed within the longitudinally extending core of filtering material; wherein the longitudinally extending core of filtering material is formed from two or more sheets of filtering material. 
     
     
         43 . The filter element according to  claim 42 , wherein the filtering material comprises paper or a non-woven material; and/or wherein the additive release vessel is a capsule. 
     
     
         44 . An apparatus for making a filter element comprising:
 a separator for separating two or more longitudinally advancing sheets of filtering material;   a gathering chamber configured to gather the separated longitudinally advancing sheets of filtering material and form a rod of partially gathered filtering material;
 wherein the separator is coupled to the gathering chamber such that the separator and the gathering chamber are configured to form a longitudinally extending recess in the rod of partially gathered filtering material; and 
 an inserter configured to insert one or more additive release vessels into the longitudinally extending recess. 
   
     
     
         45 . The apparatus according to  claim 44 , wherein the gathering chamber comprises an inlet for receiving the separated sheets of filtering material and an outlet for the partially gathered filtering material to exit, and wherein the gathering chamber tapers longitudinally away from the inlet; and/or wherein the separator is longitudinally tapered and extends into and along at least part of the length of the gathering chamber; for example wherein the separator is tapered in the same direction as the gathering chamber. 
     
     
         46 . The apparatus according to  claim 44  comprising: a preliminary chamber comprising: an inlet and an outlet; wherein the outlet of the preliminary chamber is joined to the inlet of the gathering chamber; and wherein the separator extends into and along part of the length of the preliminary chamber; for example wherein the preliminary chamber tapers longitudinally away from the inlet. 
     
     
         47 . The apparatus according to  claim 44 , wherein the gathering chamber comprises a longitudinally extending aperture for receiving the inserter; and/or wherein the gathering chamber is configured to gather the filtering material around the additive release vessel to close the recess and thereby form a continuous rod comprising a longitudinally extending core of filtering material and one or more additive release vessels; and/or wherein the apparatus comprises a rod cutter configured to cut a rod comprising a longitudinally extending core of filtering material and one or more additive release vessels to form a filter element; and or wherein the inserter comprises a rotating drum or wheel configured to insert the or each additive release vessel into the longitudinally extending recess. 
     
     
         48 . An apparatus for separating and gathering two or more sheets of filtering material, the apparatus comprising:
 a gathering chamber comprising an inlet and an outlet, wherein the inlet has a larger diameter than the outlet such that the gathering chamber is longitudinally tapered;   a separator extending at least part of the way into the gathering chamber and protruding from the inlet of the gathering chamber;   wherein the separator and the gathering chamber are configured to separate and partially gather two or more sheets of filtering material to thereby form a partially gathered longitudinally extending rod of filtering material comprising a longitudinally extending recess.