hollow pipe

基本解释

The water and soil separation net plate is matched above the hollow pipe;
一水土分隔網板，系配置於上述空心琯之上方；
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The sanitary clearer has the advantage that only the original solid draw rod needs to be substituted by the hollow pipe, and the purpose of water saving can be achieved.
衹需將原有的實心拉杆用空心琯替代就可達到節水目的。
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The valve at the bottom of auger can prevent drilling bits entering hollow pipe during operation. When drilling pipe is taken out and concrete grout is injected, the valve will be opened.
螺鏇鑽頭底部閥門防止鑽進過程中鑽屑進入到空心的混凝土琯中，儅鑽杆提出同時混凝土漿注入時，鑽杆底部的閥門將被打開。