More than just pipe dreams


More than just pipe dreams

An advanced system for making rubber seals significantly improves the efficiency of manufacturing huge concrete pipes. Trelleborg makes sure the sections will fit together without leaking. 

Anyone seeing the massive concrete pipes used for sewers and culverts might assume that making them is a fairly simple matter of pouring concrete into a mold and waiting for it to harden. But manufacturing concrete pipe is actually a very demanding process. It requires the right consistency of concrete and a lot of vibrating to make sure the concrete is compacted properly. 

Pipes are generally made in vertical molds and can weigh upward of seven tons, depending on the diameter of pipe. Pipes made with integrated sealing systems include cast-in rubber seals to assure there’s no leakage when pipe sections are joined together on site. But the vibration needed to make a pipe correctly is bad news for those seals, which can be displaced in the manufacturing process. The concept of integrating seals into manufactured pipe has been around for more than 35 years, but until recently, most seals have been a bit of a compromise. 

That has changed thanks to Trelleborg’s Forsheda F165. The F165 is a pipe sealing system that uses two grades of rubber to create an integrated seal that holds in place during manufacturing despite the vibrations. A harder rubber gives a superior tension against the steel pallet used in the pipe-making process, reducing any possibility of a seal moving out of place. The biggest advantage is the stability of this seal during the manufacture of the pipes. Pipe makers can’t tell if a seal has moved until after a pipe has cured. And if one has been displaced, all they can do at that point is scrap the pipe. The F165 significantly cuts such scrap rates. Besides making the manufacturing process easier, the F165 also simplifies the pipe installation process. The seal requires fewer installers in a trench and is ideal for mechanized pipe laying, reducing health and safety issues on site. 

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