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Polyethylene outer casing opens up new space for anti-corrosion insulation
In various industries such as petrochemicals, water treatment, heating, and industrial refrigeration, traditional anti-corrosion and insulation methods have largely relied on materials like asbestos, ash, or polyurethane. These systems often use asbestos cloth as an outer layer for protection and thermal insulation, but their effectiveness has been limited. Recently, during an interview with the Qilu Petrochemical Life Management Department's new thermal insulation material factory, the reporter learned about a breakthrough innovation: a prefabricated polyethylene thermal insulation sleeve that can be installed overhead or directly buried underground. This development is opening up new possibilities in the field of corrosion and insulation materials.
This environmentally friendly building material, which is being promoted and widely used in the construction industry, offers numerous advantages such as excellent performance, ease of installation, and eco-friendliness. As a result, it is gaining increasing popularity in the market. Li Fujun, the director of the new thermal insulation material factory at Qilu Petrochemical, explained that the polyethylene casing is made from high-density polyethylene. The product’s dimensions can be customized to meet specific user requirements. Installation is carried out by the factory itself.
The steel pipe requiring corrosion and insulation protection is placed inside the polyethylene casing, and polyurethane foam is injected into the space between the pipe and the casing, fully filling the gap. This process creates a solid, integrated structure that effectively combines the steel pipe, the casing, and the insulation layer. This method allows for both overhead and underground installation, with the entire construction process completed on-site.
According to reports, compared to traditional direct-buried insulation materials, this polyethylene casing offers significant improvements. It features high mechanical strength, excellent sealing properties, strong resistance to corrosion, low heat loss, and a long service life. The system includes fixed and sliding supports, along with mechanical compensators, which help regulate deformation and eliminate damage caused by thermal expansion and contraction. It also provides effective waterproofing, moisture resistance, and protection against acids, alkalis, salt, and oil. The overall structure remains intact, without deformation, and prevents water ingress.
The polyurethane foam layer ensures a seamless integration between the insulation and the outer sheath, solving corrosion issues for both overhead and directly buried pipes. With a service life of up to 30 to 50 years—far exceeding the typical 3 to 5 years of traditional materials—this innovative solution offers long-term cost savings and reliability. The polyurethane foam also provides excellent mechanical and thermal insulation properties, capable of withstanding normal operating temperatures of up to 120°C, and short-term exposure up to 130°C. This makes it highly suitable for a wide range of industrial applications.