Abstract: A method of forming a filter unit comprised of a filter element and an encircling peripheral encasement frame to which the filter element is sealed. The frame is moulded in situ by solidification of a liquid, solidifiable moulding composition (e.g. a curable resin or a matter thermoplastic resin that solidifies on cooling) provided around the periphery of the filter element. The method may comprise the steps of: (i) providing a filter element having front and rear faces and a bounding peripheral edge, (ii) locating around the peripheral edge of the element a mould unit which seals against peripheral regions of the front and rear faces and which together with the peripheral edge defines a mould cavity, (iii) filling the mould cavity with a solidifiable, liquid moulding composition, (iv) effecting conversion of the liquid to a solid, and (v) removing the mould thereby producing the filter element.

Abstract: An insert mould tool for moulding an annular moulded portion onto an insert such as a filter sheet of a filter cartridge comprises a plurality of mould pieces and means for applying pressure to the mould pieces. Each mould piece comprises complementarily shaped mating surfaces and can be assembled to define an annular mould cavity intersecting at least one mating surface for defining the shape of the moulded portion and an insert-receiving cavity for receiving a portion of the insert. The insert-receiving cavity comprises a sealing portion extending radially inwardly of the annular mould cavity for sealing receipt of a portion of the insert, the sealing portion being exerting a substantially evenly distributed pressure across an area thereof when pressure is applied to the mould pieces. Also disclosed is a method of insert moulding, and a filter cartridge.

Abstract: A method of forming a filter unit comprised of a filter element and an encircling peripheral encasement frame to which the filter element is sealed. The frame is moulded in situ by solidification of a liquid, solidifiable moulding composition (e.g. a curable resin or a matter thermoplastic resin that solidifies on cooling) provided around the periphery of the filter element. The method may comprise the steps of: (i) providing a filter element having front and rear faces and a bounding peripheral edge, (ii) locating around the peripheral edge of the element a mould unit which seals against peripheral regions of the front and rear faces and which together with the peripheral edge defines a mould cavity, (iii) filling the mould cavity with a solidifiable, liquid moulding composition, (iv) effecting conversion of the liquid to a solid, and (v) removing the mould thereby producing the filter element.