【机械工程】下水孔冲击方式（锤子）

down-the-hole drill【矿】;down-hole drill【矿】

cleaning of down-hole filters

cleaning of down-hole gravel packs

cleaning of down-hole screens

down-hole flowmeter【油气】

down-hole impacting means

down-hole troublesome condition

down-hole drill【矿】;down-the-hole drill【矿】;in-hole perforator【矿】