초록 ▼

A filter for removing solid contaminants from plastic melt as well as homogenizing the plastic melt prior to injection, including a generally cylindrical filter screen having an inlet passage receiving the unfiltered plastic melt. Axially arranged series of relatively large diameter holes extend bet

A filter for removing solid contaminants from plastic melt as well as homogenizing the plastic melt prior to injection, including a generally cylindrical filter screen having an inlet passage receiving the unfiltered plastic melt. Axially arranged series of relatively large diameter holes extend between the inlet passage and filter grooves formed in the surface of the filter screen. A first stage, coarse filtration is achieved by flow through the holes radially outwardly from the inlet passage into each of the filter grooves. A second stage, fine filtration occurs by flow from the filter grooves through circumferential clearance spaces located between each of several lands separating the filter grooves and the interior of the filter cavity. Filtered plastic is collected in axially extending discharge grooves also formed in the filter screen surface intermediate the pairs of filter grooves. Each discharge groove is in communication with a discharge passage collecting the flow of filtered plastic melt from each of the discharge grooves. Flow through the clearance spaces and discharge grooves affords linear flow paths, enhancing the homogeneousness of the plastic melt and uniformity of density in the molded product.

대표청구항 ▼

CM,1. A filter arrangement for an injection molding machine comprising: a main body having an internal bore formed therein defining a filter cavity; a filter screen received within said filter cavity; said filter screen generally cylindrical to be interfit within said filter cavity and wherein said

CM,1. A filter arrangement for an injection molding machine comprising: a main body having an internal bore formed therein defining a filter cavity; a filter screen received within said filter cavity; said filter screen generally cylindrical to be interfit within said filter cavity and wherein said filter cavity is correspondingly cylindrically shaped; said filter screen being formed with at least one filter groove formed into the periphery of said filter screen and extending axially for a portion of the length of said filter screen, and a discharge groove circumferentially spaced from said at least one filtering groove, said discharge groove formed into the periphery of said filter screen and extending axially along a portion of the length of said filter screen, said at least one filter groove and said at least one discharge groove being separated by an axially extending land, said land being radially spaced to form a circumferentially extending clearance space; inlet passage means including an interior inlet passage extending for a portion of the length of said filter screen; an outlet passage means including at least one discharge groove; said inlet passage and outlet passage means each in communication with said at least one filter groove, discharge groove, and circumferentially extending clearance space to define a flow path through said filter with filtration occurring by flow therethrough; and further including a series of through holes extending between said at least one filter groove and said inlet passage, whereby a two-stage filtering action is enabled by flow through said holes into said filter groove thence through said clearance space into said discharge groove; and wherein said through holes are of larger diameter than the distance across said at least one clearance space, whereby a coarse filtering action is achieved by flow through said large diameter holes into said filter grooves and a fine filter action achieved by flow from said filter groove through said clearance space and into said discharge groove.