Patent ID: 11872416
Assignee: MOLDEX-METRIC, INC.
Field: Other special machines (Mechanical engineering)
Classification: CPC A  B | IPC A  B

Claim 17:
18. A method of making a filter for mounting to a face piece or respirator, the method comprising:
providing a layer of flexible plastic netting material having a plurality of perforations allowing free passage of air through the perforations of the plastic netting material;
providing a layer of polymeric filter media for filtering impurities in air passing through the filter;
positioning the layer of flexible plastic netting material and the layer of polymeric filter media to lie one on top of the other to form a multilayer of flexible plastic netting material and polymeric filter media;
moving the multilayer of flexible plastic netting material and polymeric filter media to a pleater;
pleating the multilayer of flexible plastic netting material and polymeric filter media to form a pleated composite layer of flexible plastic netting material and polymeric filter media having an overall structure of continuous and adjacent pleated folds;
moving a length of the pleated composite layer to a filter element pre-former;
by the filter element pre-former, compressing peripheral edges of the length of the pleated composite layer to form a preformed pleated filter element;
moving the preformed pleated filter element to an assembly and sealing unit and combining the preformed pleated filter element with the preformed filter mounting element, the preformed filter mounting element being semi-rigid and molded from a plastic material, the preformed filter mounting element including
a mounting connector for mounting the filter to the face piece or respirator, and
a plenum devoid of the pleated filter element, the plenum defining a free volume between the mounting connector and the pleated filter element allowing passage of unrestricted inhaled air into the face piece or respirator after the inhaled air has passed through the polymeric filter media of the filter,, the assembly and sealing unit having a mold configuration conforming generally to contours of the preformed filter mounting element, the mold configuration having an upper mold and a lower mold; and
by the upper mold and the lower mold, melting and pressing together a flange formed by a plastic material of the preformed pleated filter element and a flange formed by the plastic material of the preformed filter mounting element thereby to join and bond together, by the melting of the plastic material of the preformed pleated filter element and the plastic material of the preformed filter mounting element, the flange of the filter element and the flange of the preformed filter mounting element to form an air impermeable seal extending around a periphery of the filter.