孔口；孔( orifice的名词复数 )；洞口；
1. 门阀、球阀、挡板、旋塞、防爆盘、喷嘴：K Mechanical components 机械部件 | KA Gate valves, globe valves, dampers, cocks, rupture disks, orifices 门阀、球阀、挡板、旋塞、防爆盘、喷嘴 | KB Gates, doors, dam boards 闸门、门、挡板
