?双面槽    double groove

?双槽焊    double groove weld

?人字齿轮    double helical (or herring-bone) gear

?双层船壳    double hull

?复式喷射器    double injector

?双螺帽    double nut

?双通净油系统    double pass purifying system

?双边办公桌    double pedestal desk

?双排柱    double pillar

?双重管卤水冷却器    double pipe brine cooler

?双管冷凝器    double pipe condenser

?复板舵    double plate rudder

?双口滑阀    double ported slide valve

?双油头    double probe

?双滑车起货机,双索绞    double purchase winch

?双索绞车    double purchase winch

?双级减速齿轮    double reduction gear

?两段减速齿轮    double reduction gear

?双行铆接    double rivet joint

?双行铆[钉]接[合]    double riveted joint

?双行铆接    double riveting

?双排缸回转引擎    double rotary engine

?双座阀    double seat (or beat) valve

?双座停止阀    double seat stop valve

?双座阀    double seat valve

?双面剪    double shear

?双蔽叶轮    double shrouded impeller

?双边[频]带发送    double side-band transmission (DSB)

?两侧吸入叶轮    double sided impeller

?双面搭板接合    double strapped joint

?双吸[式]泵    double suction pump

?双转环钩    double swivel hook

?双重拉伸试验    double tension test

?双螺纹    double thread

?双纹螺钉    double threaded screw

?双拐曲柄轴    double throw crankshaft

?双投开关    double throw switch

?双面焊接接合    double welded joint

?双线式    double wire system

?双断开关    double-break switch

?双管设备    double-hose rigs

?双面丁形槽    double-J groove