HDPE‑EVOH double‑layer composite pipe is a high‑performance thermoplastic piping solution specially engineered for underground fuel transmission at gas stations. Manufactured by multi‑layer co‑extrusion technology, the pipe adopts HDPE as inner and outer structural layers while embedding EVOH as the core hydrocarbon‑resistant barrier layer. It is supplied in coil and straight‑pipe forms with multiple caliber options, compatible with imported PE electrofusion fittings for on‑site connection. Widely used in fuel supply pipelines, vapor recovery pipelines and tank‑dispenser connecting pipelines, this piping system copes with harsh underground conditions including soil corrosion, stray current and ground settlement. Strict performance requirements are imposed on hydrocarbon permeation resistance, mechanical impact strength, underground anti‑aging property and joint sealing reliability.
Traditional pipeline materials show evident drawbacks for buried fuel pipeline projects. Carbon steel pipes possess high mechanical strength but suffer from underground electrochemical corrosion. Damaged anti‑corrosion coatings during transportation and installation will trigger rust, pitting and medium leakage, requiring regular maintenance and bringing high full‑cycle costs. Single‑layer HDPE pipes avoid metal corrosion yet lack effective barrier structures. Long‑term fuel permeation causes gasoline volatilization loss and potential soil contamination. Ordinary composite pipes without EVOH barrier cannot satisfy modern anti‑permeation standards for gas stations. Poor‑quality fusion joints may result in hidden leakage defects after burial, which are hard to detect and repair.
This HDPE‑EVOH double‑layer composite pipe is produced through precise multi‑layer co‑extrusion processes. The outer HDPE layer delivers excellent wear‑resistance, anti‑aging performance and soil‑stress tolerance to adapt to complex underground environments. The inner HDPE layer resists swelling and erosion from liquid hydrocarbon fuels. The sandwiched EVOH functional layer serves as an efficient barrier against hydrocarbon molecule penetration, greatly suppressing fuel permeation and volatile loss. Coil‑type pipes cut down intermediate joints for long‑distance laying and lower connection‑point leakage risks. Straight‑type pipes are applicable to short‑distance and segmented layout to meet diversified on‑site layout demands.
Matched imported PE electrofusion fittings realize reliable electro‑fusion welding on site. Under standardized construction procedures, electro‑fusion joints form integral sealing interfaces and effectively eliminate hidden leakage risks at connecting positions. Benefiting from favorable flexibility, the pipe can withstand slight ground settlement and foundation deformation without brittle fracture. Different from steel pipelines, the composite pipe needs no anti‑corrosion coating or cathodic protection, simplifying construction workflows and reducing later‑stage maintenance workload. Complete supporting accessories include electro‑fusion couplings, elbows, tees and transition joints to construct a full‑set underground fuel piping network.
Vohon Petrochemical provides both coil and straight‑pipe products in various specifications. Custom dimensions are available according to project flow requirements, burial depth, pipeline routes and field layout conditions. Every product undergoes strict factory inspection before delivery. The product set is convenient for loading and transportation, brings moderate on‑site construction workload, shortens project cycles and has minimal influence on daily gas‑station operations. All pipe bodies and matched electrofusion fittings comply with international gas‑station piping standards. Optimized raw‑material formula guarantees stable barrier performance and mechanical properties for long‑term underground service. Complete technical documents such as material test reports and construction guidance manuals can be provided.