明杆平行式双闸板闸板 Double Disk Parallel Gate Valves ; Double Disk Parallel ; DoubleDiskParallelGateValves

明杆平行式双闸滑阀 rising-stem double-disk parallel slide valve ; disk parallel slide valve

明杆平行式双闸板闸阀 double disk parallel gate valves

明杆平行式双阀板阀板 Double Disk Parallel Gate Valves