| 摘要 |
<p>1488705 Valves IMPERIAL CHEMICAL INDUSTRIES Ltd 23 May 1975 [25 June 1974] 28099/74 Heading F2V In a valve, particularly for laboratory glassware, the valve member comprises a mandrel 11 around which are placed 0-ring seals 12, 13, 14, 15 located in grooves and the whole is enclosed in a plastics sleeve 16. The O-rings press the sleeve into sealing contact with the bore 5 and the spaces between form passageways through which a port 2 may be connected with a port 3 or 4 when the valve member is moved axially by rotating a cap 17. In another embodiment, Fig. 2 (not shown), the 0-rings 13, 14 are replaced by a single O- ring (23) placed obliquely around the mandrel. In this embodiment flow is controlled by rotating the valve member by a cap as in Fig. 1. The small axial movement of the valve member is insufficient to affect flow. In a further embodiment, Fig. 3 (not shown), generally similar to that of Fig. 2, only a short length of the cap and valve body are screw threaded and on assembly the cap is screwed to a point at which the threads dis-engage so that on rotation there is no axial movement of the valve member. In a yet further embodiment, Fig. 4 (not shown), for a simple two-way valve similar to that of Fig. 1, the cap is a sliding fit on the body and is operated by push/pull. In all the embodiments the O-rings may be of rubber and the sleeves of polyethylene, nylon, a fluorine-containing polymer such as PTFE, heat-shrinkable polypropylene or heat-shrinkable tetrafluorethylenehexafluoropropylene copolymers. The thickness of the sleeve is preferably at least 0À3 mm. and not more than 0À63 mm. The body may be made of glass or rigid thermoplastic material, reinforced, e.g. with glass fibres.</p> |
