| 摘要 |
<p>1,204,816. Valves. TECHNICON CORP. 30 Oct., 1968 [13 Nov., 1967[, No. 51541/68. Heading F2V. [Also in Division H1] A combined valve and electric switch device for process control such as in a continuous flow automatic system for chromatographic analysis, comprises a number of resiliently compressible tubes 86 through which different eluting liquids are pumped, and means for occluding the tubes consisting of an array of cam-shafts 54 arranged round a rotatable support 42, 44, 46, so that the tubes are compressed against a platen 68. Those cams such as 130, between the support plates 44, 46, are arranged to operate snap-action switches 106, 108, 110, 112 through pivoted arms 116, 118, 120, 122 to control a drive motor 134 and pumps supplying the tubes. The camshafts are releasably mounted in the support by spring clips 58, for replacement through an access door 133. The phasing of the switches is adjustable by screw tappets 124, Fig. 5 (not shown). Spacers in place of some of the cams 130 are arranged to miss the switches. The arm may have a narrow follower part 128N so that it drops behind each cam, or a wide follower part 128W so that it is held actuated by one cam until engaged by the next succeeding cam. The occlusion of the tubes 86 is similarly controlled, in that a spacer, following an occluding cam 98, will allow the tube to open, whereas two following cams 98 will hold the tube occluded continuously. The direction of motion of the cams is counter to the flow direction so that no pumping action occurs. The drive motor is energized through a latching relay (140), Fig. 5 (not shown), initially by a pulse from an external switch. The latter may be incorporated in a clock mechanism, with a continuously advanced punched tape. The tubes are located by grooved blocks (82) and collars (88) adhered to the tubes. Automanual selector switches (146) are provided, with a manual push button control (148), Fig. 3 (not shown).</p> |
