A sleigh ride in South Africa

Polyethylen pipe OD 1200 mm

There is a water shortage in South Africa. However, the industry is booming in the area around Johannesburg and the companies requiring large amounts of this limited resource. Therefore from various rivers, such as the Crocodile River or the Mokolo River, therefore, water is diverted, stored in large reservoirs and delivered to the industry. The two water reservoirs Mokolo and Crocodile River have been connected to a large-sized concrete pipeline since the 1970s. This pipeline was leakage for some time and therefore professionally rehabilitated with AGRULINE HDPE 100-RC pipes.

HDPE pipe pit with 5 m length
The pipe pit with 5 m length was too short to install a butt welding machine.
electro fusion welding of HDPE pipes
Preparatory work for the electro fusion welding.

The challenge was to rehabilitate the existing concrete pipe, OD 1700 mm and 150 m long that runs underground using a HDPE pipe (high density polyethylene pipe). Because a pump station was built on the construction site at the same time, the space in the excavation pit was conceivably tight. Our partner Astore Keymak (AK) commissioned the AGRU technical engineering to find a workable solution within the scope of the required work.

Our application engineers were able to propose a special solution thanks to their extensive knowledge and experience. The cramped space in the only 5 m long pipe pit prevented the installation of a butt welding machine. Thus the length of the pipe rods was limited to 5 m, because otherwise they could not be inserted into the pipe. In addition, the rough concrete pipe made the pipe installation difficult. Our technicians planned and implemented an extraordinary solution: to ensure easy handling in the short construction pit, between 4 and 5 m long pipe segments with OD 1200 mm were selected. These were equipped with “runners” in Bad Hall and delivered together with our AGRU e-couplers as a ready-to-use system solution to South Africa. Thanks to the “runners”, the HDPE pipes could slide like a sled into the concrete pipe without being damaged. The “runners” were polyethylene pipes with a small OD of only 63 mm. Each pipe was welded with two “runners” by extrusion welding technique. At the two ends of the pipe segments, our engineers left enough space free to attach e-couplers to the OD 1200 mm pipe. Because of the cramped space in the ditch, this was the only acceptable welding solution.

polyethylene pipe OD 1200 mm
The new pipe was inserted by means of winch and pulley, not pulled in.
polyethylene pipe OD 1200 mm
The polyethylene pipe OD 1200 mm slid like a sled on the “runners” into the old concrete pipe.

With a winch and pulley, the new pipe was then inserted step by step into the old pipe. It was not pulled in, in order to avoid a tensile load on the welds. The existing annulus was finally dammed with concrete. AGRU on-site application engineers ensured that the construction team could work without any problems. Thanks to this brilliant solution, the installation was made easier despite the tight space conditions and a permanently leak-free system could be installed. Due to the unique mechanical and chemical properties of HDPE 100-RC in terms of service life, pumped medium and water hammer, a long life expectancy can be achieved.

Flanges conect HDPE pipes
The annulus was dammed with special concrete and the connection to the existing steel pipe was made by means of a flange.

Here you can find more information about our AGRULINE HDPE 100-RC piping system.

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