Pilot tube for construction of main pipe line, has mantle that consists of five or six longitudinal sheets, where tube is provided through steel bandage, which is continuous along length and is fitted at mantle in sealed manner

摘要

The tube has a mantle that consists of five or six longitudinal sheets (1) made of steel, where side edges of the sheets are bent inwards to the tube, and adjacent parts of the side edges (2) inside the tube are welded with one another. The tube is provided through a bandage made of durable material such as steel. The bandage is continuous along the length and is fitted at the mantle in a sealed manner. The sheet has the form of circular sectors in the cross section and is laid concentrically with the mantle.