Pleated filter and method and apparatus for fabricating same

A method for fabricating a filter for separating constituent components from a fluid, said method comprising the steps of:

• forming a plural-layer sheet-like member, having a plurality of layers of material adjacent one another, into an elongated and peripherally continuous tube;
• folding said tube to provide multiple sequentially adjacent plural-layer peripheral pleats having fold lines disposed generally transversely of the length of said tube;
• the step of forming including the steps of:
• feeding said plurality of layers from respective individual locations in adjacent relation into an entrance to a longitudinally-extending, transversely-configured passage of predetermined transverse cross-section;
• and
• conveying the adjacent layers longitudinally through said passage in side by side relation;
• the step of conveying including pneumatically conveying said layers by flowing a conveying gas into said passage at a conveyor location with a flow component directed longitudinally of said passage.

A method for fabricating a filter for separating constituent components from a fluid, said method comprising the steps of:

• forming a plural-layer sheet-like member, having a plurality of layers of material adjacent one another, into an elongated and peripherally continuous tube;
• folding said tube to provide multiple sequentially adjacent plural-layer peripheral pleats having fold lines disposed generally transversely of the length of said tube;
• the step of forming including the steps of:
• feeding said plurality of layers from respective individual locations in adjacent relation into an entrance to a longitudinally-extending, transversely-configured passage of predetermined transverse cross-section;
• and
• conveying the adjacent layers longitudinally through said passage in side by side relation;
• the step of folding including the step of withdrawing the sheet-like member from an exit of said passage at an average linear speed which is lower than the linear speed at which said layers are fed to said entrance so as to cause said sheet-like member to be multiply crimped in said passage.

A method for fabricating a filter for separating constituent components from a fluid, said method comprising the steps of:

• forming a plural-layer sheet-like member, having a plurality of layers of material adjacent one another, into an elongated and peripherally continuous tube;
• folding said tube to provide multiple sequentially adjacent plural-layer peripheral pleats having fold lines disposed generally transversely of the length of said tube;
• the steps of folding comprising the steps of:
• delivering said sheet-like member to an entrance of a longitudinally-extending transversely-confined passage having a predetermined transverse cross-section, said sheet like member being delivered at a first average linear speed;
• conveying said sheet-like member longitudinally through said passage;
• and
• withdrawing said sheet-like member from an exit of said passage at a second average linear speed which is lower than said first average linear speed in order to cause the sheet-like member to be multiply crimped in said passage.

Apparatus for fabricating a multi-layer filter comprising:

• a longitudinally-extending passage of predetermined cross-sectional configuration, said passage having an entrance and an exit;
• a delivery means for delivering a sheet-like member having plural layers into said passage via said entrance at a predetermined speed, with said plural layers disposed in successively adjacent relation to one another, said plural layers being disposed transversely of the longitudinal direction of said passage;
• a conveyor means for translating said sheet-like member longitudinally through said passage;
• a forming means in said passage for forming said sheet-like member into an elongated hollow tube member having an continuous transverse periphery;
• said forming means including a pleating means for pleating said sheet-like member while it is conveyed from said passage to form multiple successively adjacent transverse pleats in said sheet-like member, such that each pleat includes said plural layers and a fold line oriented transversely to the longitudinal direction of said passage;
• and
• a means for withdrawing said tube member from said passage at a speed lower than said predetermined speed.