Filter pipe made of concrete and/or plastic and optionally glass fibers used for micro-tunneling with the aid of an advance working machine has openings in its casing with filter bodies

摘要

Filter pipe made of concrete and/or plastic and optionally glass fibers has openings (5) in its casing with filter bodies (6). Preferred Features: The openings make up 10-30, preferably 15-25% of the outer surface of the casing and are formed as circular recesses conical vertical to the pipe axis and conical to the inside of the pipe. The filter bodies consist of sand grains adhered together. The empty chambers are filled with a gel or tenside as protective material.