hollow pipe

基本解释

The water and soil separation net plate is matched above the hollow pipe;
一水土分隔网板，系配置于上述空心管之上方；
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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.
只需将原有的实心拉杆用空心管替代就可达到节水目的。
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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.
螺旋钻头底部阀门防止钻进过程中钻屑进入到空心的混凝土管中，当钻杆提出同时混凝土浆注入时，钻杆底部的阀门将被打开。