Since the early 1960s, and shortly after the first introduction, polyethylene pipes have been increasingly used for offshore applications. Fluid discharge, fluid transfer from under the river or lake, and getting fresh water and saline water are the major applications of polyethylene pipes in the sea. In addition to the main applications mentioned above, they may be used at sea, in cases such as temporary pipelines floating on the water surface, installation on marshy land and using in dredging operations.
For installations that are mainly built by the seas and lakes and require large scale cooling systems, using seawater is the cheapest and most convenient solution. Double-wall polyethylene pipes with core-tube play a major role in transferring large volumes of seawater to the pumping part of the cooling system. With the development of the country’s industry in areas near the sea, the use of large diameter pipes for various industries has also emerged.
How to place on the seabed
Double-wall polyethylene pipes up to 4000 mm in diameter can be easily welded into pieces of varying lengths and can be placed on the seabed. Stub-end is also used to connect the spools to each other. The advantages of double-wall polyethylene pipes with core-tube are as follows:
- High flexibility of pipes
- High quality welding beyond the standard in fittings
- Complete sealing
- Engineering facilities
- Designing to offer optimal conditions to the employer
We are proud that for the first time in the world, the company’s double-wall polyethylene pipe with a diameter of 2500 mm has been worked in the sea. This pipeline was 1700 meters long and was installed at a depth of 25 meters.
High quality floats can be manufactured with double-wall polyethylene pipes. High density polyethylene (HDPE) is lighter than water and makes the pipe float on the water. If the openings of the pipes are closed, their buoyancy will increase and they can withstand heavy loads.
These materials are resistant to saline water and, unlike steel floats, do not rot. Neither they do stay out of the water too much, nor do they sink too deep into the water that water covers them.
The various chambers inside the floats control the water level. Separate chambers prevent complete drowning when the body is damaged and perforated, preventing it from sinking into the water.
The company’s double-wall polyethylene pipes can be connected to large lengths without any problems. The maximum length depends on the type of profile used in the double-wall polyethylene pipe and the method of its installation in water.
In Germany, most of the marine basins were built between 1970 and 1985. The basins were taken to the North Sea, the East Sea and the Elbe and Rhine rivers. Since then, the foreign partner of Tadbir Novin Sazan has acquired the knowledge of how to work with static structures and install pipelines.
Collaborating with construction companies is important because such projects require more work than ground pipe technology. Tadbir Novin Sazan double-wall polyethylene pipes with core-tube are connected without any problems over long lengths. The maximum length depends on the type of profile used in the double wall pipe and how it is installed in the water.
How to connect
External welding is used to connect the pipes. Because of the mechanical strength of the pipes, it is possible to move them in the water and they can be slept on the sea floor without causing any damage.
Of course, Tadbir Novin Sazan also uses special connections that can be built by divers under the sea. Only in this case it is possible to connect to buildings or multiple pipelines. The company uses a plastic connector to do this.
Due to the light weight of polyethylene pipe profiles than water, there is no problem in moving them in water. Placing the pipes on the seafloor is possible by applying more pressure from outside on the pipe or by creating anchor, or by filling the hollow chambers of the pipe profile, for example with cement.
The basin not only needs a good pipe, but it must also have a complete system, the output buildings are very important, the cross section of the pipe is enlarged, and it must be hydrodynamic. HDPE systems are also manufactured by the company and delivered to the construction site.