Memtec America Corporation

Pall Corporation

Memtec LLC

Usf Filtration and Separation Group, Inc.

Usf Filtration & Separations, Inc.

Usf Fultration and Separations Group Inc.

Robert J Schmitt

Brian Mozelack

Robert D Connor

Steven D Barboza

Charles S Hoffman

Clinton V Kopp

Anthony C Shucosky

Timothy W Yingling

Ronald R Gschwandtner

Son Ngoc Nguyen

Praveen Jana

Charles Hoffman, Jr

Filter cartridges may have a core element formed of a non-filtering, self-supporting non-woven mass of indefinite length continuous synthetic polymeric core fibers, and at least one annular filtration zone layer formed of a mass of non-woven indefinite length continuous synthetic polymeric filtration fibers. The non-woven core element is most preferably formed in situ during filter cartridge manufacturing by melt-blowing synthetic polymeric core fiber streams toward a forming mandrel. The non-woven core element is completely solidified prior to the filtration zone fibers being melt-blown thereon so that the core and filtration fibers are predominantly mechanically interlocked with one another, instead of being melt-bonded thereto. Filter cartridges of predetermined length may be cut from an upstream filter cartridge preform of indefinite length by subjecting the preform to forced cooling air to thereby minimize (if not eliminate entirely) significant filter cartridge shrinkage over time. In addition, a cutter assembly may be mounted laterally of the preform, but is capable of rate-synchronized longitudinal movement with the preform during its cutting operation.

Apparatus for making melt-blown filter cartridges

Melt-blown tubular core elements and filter cartridges including the same

Substantially constant tension is maintained on a melt-blown nonwoven fibrous sheet by mounting the sheet take-up roller for longitudinal movements relative so as to accommodate the increasing diameter of the sheet material being wound convolutely on the take-up roller. Sheet tension during production is thereby maintained substantially constant by virtue of a continual increase in the longitudinal distance (in relation to the machine direction) between the fiber collection mandrel and the take-up roll. Preferably, tension control is achieved by a pneumatic pressure-regulating system which includes at least one rotatable press roller which is longitudinally fixed in position relative to the collection mandrel and is in contact with the sheet material being wound around the take-up roll. The take-up roller is pneumatically advanced toward the press roller by the pneumatic actuation of at least one air cylinder. Thus, as the diameter of the sheet material being wound around the take-up roll increases, the pneumatic ram of the air cylinder will cause the pneumatic pressure of the air cylinder to correspondingly increase. This increase in pneumatic pressure is sensed by a pneumatic pressure regulator which vents sufficiently to decrease the pneumatic pressure acting on the air cylinder to a predetermined set point pressure. In this manner, the pressure exerted on the sheet material between the positionally fixed press roller and the longitudinally movable take-up roller is maintained substantially constant during production of the nonwoven sheet material.

Apparatus and method for making melt-blown nonwoven sheets

Apparatus and methods are disclosed whereby elongate preformed thermoplastic elements are friction-welded coaxially in an end-to-end manner so that the core elements are joined integrally to one another. Most preferably, the elongate elements are perforated tubular elements formed of a thermoplastic material which are employed as core elements in the production of cylindrical melt-blown filter cartridges. As such, the integrally joined core elements can be rotated and traversed as a unit relative to a melt-blowing die during the continuous production of indefinite length cylindrical melt-blown filter cartridges.

Apparatus and method for integrally joining preformed thermoplastic core

Filtration medium is formed of a mass of nonwoven melt blown support and filtration fibers which are integrally co-located with one another. The support fibers have, on average, relatively larger diameters as compared to the filtration fibers which are integrally co-located therewith. Preferably, the filtration medium is disposed within at least one annular zone of a filtration element, for example, a disposable cylindrical filter cartridge having an axially elongate central hollow passageway which is surrounded by the filtration media. A depth filter cartridge in accordance with the present invention may thus be formed having one or more additional filtration zones (which additional filtration zones may or may not respectively be provided with integrally co-located support fibers) in annular relationship to one another. As a result of the melt blown, nonwoven fiber structure in accordance with the present invention whereby at least one filtration zone is comprised of relatively larger diameter support fibers integrally co-located with relatively smaller diameter filtration fibers, a filter cartridge having a wide range of 'engineered' physical properties (e.g., in terms of filtration, pressure drop tolerance and the like) can be provided.

Method of making filtration media having integrally co-located support

Apparatus for integrally joining elongate preformed thermoplastic

The apparatus is provided to make a melt blown fibrous medium and includes first and second melt blowing dies for respectively issuing first and second streams of melt blown fibers along first and second melt blown paths. The first and second streams are issued on a forming surface where the streams are collected to form a melt blown fibrous medium. A movable transfer surface is interposed between the first die and the forming surface in the first path so that the first stream of melt blown fibers impinges on the transfer surface in advance of the forming surface such that the first stream is transferred to and brought into contact with the second stream of melt blown fibers on the forming surface.

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Stewartstown, PA, United States of America

Robert J Schmitt