| 摘要 |
<p>1298593 Moulding filters STANDARD SCREW CO 9 March 1970 [10 March 1969] 11204/70 Heading B5A [Also in Division B1] A filter comprising a housing 10 closed by a cover-plate 22 and containing a transversely extending pleated filter element 12 is made by locating the cover-plate upon a mould 30, the cover-plate being provided with apertures 52 through which pins 44 and 46 carried by the mould plate project, casting a layer 20 of heat setting plastisol of, for example, PVC upon the cover-plate, and whilst the layer is still sufficiently fluid, applying the housing and filter element to it so as to embed the rim of the housing and one edge of the filter element in the layer. The layer is then heat set. Pins 44 project beyond the surface of the layer to form preformed inlet apertures whereas the layer extends over pin 42 to form a thin region rupturable just before use to form an outlet aperture. Pins 44 are apertured to allow the expanding air within the housing to escape during the heat setting of the layer. The other edge of the filter element may be bonded to the housing by a cast layer 18 of a suitable plastisol. Recesses in the mould about the pins 44 and 42 form resilient mounting grommets 58 and, if desired, these recesses may be filled with a more resilient material before the latter 20 is cast. As in Figure 1, a composite mould may comprises a series of moulds located sideby-side each surrounded by an upturned material retaining wall 34.</p> |
