明杆闸阀: outside screw stem rising through handwheel type gate aleoutside screw stem rising through handwheel type gate valve
三通: 1.[机械工程] triplet; tee; tee joint; [工业] wye; y; yoke2.(指通邮、通商、通航) “three exchanges”: exchanges of mails, trade, air and shipping services; the opening of postal, aviation and navigational s