LOW-PRESSURE REINFORCED CONCRETE PIPE AND ITS MANUFACTURING METHOD Russian patent published in 2022 - IPC B28B21/18 F16L9/08 

FIELD: construction.

SUBSTANCE: group of inventions relates to the construction of underground low-pressure water supply and drainage systems from reinforced concrete pipes and their factory manufacture. A reinforced concrete pipe with a round hole with a diameter of 300-1200 mm for underground low-pressure pipelines transporting non-aggressive liquids with a temperature of up to 95°C under a pressure of up to 6 atm, mounted by an open trench method with backfilling of soil or a closed pushing method – micro-tunneling using rubber sealing rings with a cross-sectional size of 16-24 mm for joining adjacent pipes, consists of a middle part, bushing and bell-shaped docking ends. In this case, the pipe is made of unstressed heavy concrete, reinforced with a single steel welded wire orthogonal or spiral-cross cylindrical or ovoidal frame. Pipe concrete has classes of axial tensile strength of at least R_bt 3.2 and compression of at least B45. The pipe has a working length of 2.5-3.5 m, and it is made with a bell that does not protrude beyond its outer cylindrical surface. The middle part of the pipe has an outer cylindrical surface for pipes of all diameters of 300-1200 mm or partially cylindrical surface with a flat support sole for pipes with a diameter of 800-1200 mm. A pipe wall has a thickness equal to 1/5-1/12 of its inner diameter. The outer surface of the middle part of the pipe is made polymer of a sealed thin-sheet polyethylene or polypropylene lining cover with a thickness of 3-6 mm with inner V-shaped point anchors with a height of at least 15 mm, fixing the cover in concrete. Docking ends of the pipe have prefabricated polymer – polyethylene or polypropylene – rings of angular cross-section, consisting of polymer rings-cuffs hermetically welded to each other, with a thickness of 20-40 mm: inner rings of 50-80 mm wide and outer rings of 80-120 mm wide. In this case, the inner ring-cuff of the bell end of the pipe is designed to push a rubber sealing ring, when pipes are joined, and the inner ring-cuff at the bushing end of the pipe is a stop for the rubber sealing end, when pipes are joined. The bushing end of the pipe has a reinforced concrete step with a width of 80-100 mm, consisting of three parts: cylindrical one with a width of 25-30 mm at the end of the pipe, designed to install the rubber sealing ring before joining pipes, conical one, along which the sealing ring moves when it is pushed, and cylindrical one, on which it is fixed after the end of joining pipes. Outer rings-cuffs are connected hermetically by welding flush along the outer surface of the pipe with a lining cover. Behind the prefabricated polymer ring of the bell end of the pipe, there is a flat chipboard ring (hereinafter – CBR) with a thickness of 20-25 mm, the inner diameter of which is equal to the diameter of the conditional passage of the pipe. CBR is tightly fixed to the end of the inner polymer ring-cuff with steel screws of 40-60 mm long, and it also has additional steel screws screwed into it, ensuring reliable adhesion of CBR to hardened concrete of the pipe. According to the method for manufacturing a pipe, a false mold with CBR in its lower part and a reinforcing frame with fixers of its design position are placed in an outer vertical detachable steel mold. The assembled formwork, consisting of the outer steel mold and a completed false mold, is moved by a crane to a turntable of a molding post, supporting it with end surfaces of the prefabricated polymer ring and the outer flat surface of CBR on a non-removable steel ring. The pipe is formed by radial pressing using a roller head compacting a concrete mixture and forming the inner surface of the pipe.

EFFECT: creation of a reliable structure of a reinforced concrete low-pressure pipe and increase in the efficiency of its manufacture.

2 cl, 1 dwg, 2 tbl