Wall Thickness: 18 mm

Length: 322 m

Application: Rainwater Pipeline

Project Introduction：

This DN1800 main Rainwater pipeline was buried at a depth of 4.7 m to 6.1 m and ran beneath a railway subgrade. Severe offset joints and disconnections have occurred on the pipeline, leading to continuous water seepage that eroded the railway subgrade and created an imminent safety hazard.

Construction Challenge：

The DN1800 allowed an adult to walk upright inside. Installing the nearly 2-meter-diameter, 18 mm wall Thickness liner precisely 6 meters underground through manholes and curing it into a seamless "pipe-within-a-pipe" via UV light posed unprecedented technical difficulties.

1. Difficulties in liner manufacturing: The tension control and uniformity of fiberglass weaving, resin impregnation, and outer film lamination for ultra-large-diameter liners were extreme tests. The enormous weight of the liner can easily twist or scratch during lowering, and any folds or hollow sections would render all previous efforts futile.

2. Complex curing process: Extra-large liners demanded exponentially higher UV intensity and uniform light coverage. The light train required several times the power of standard units, with travelling speed calibrated to centimeters per minute and stringent curing temperature regulation.

3. Restrictive construction environment: The pipeline crossed an active railway with uninterrupted train operations throughout construction. Confined space entry, toxic and hazardous gas monitoring and tight deadlines for construction and acceptance required the rehabilitation to be completed within a minimal timeframe.

Integrated Solution

After multi-party technical evaluation, UV-CIPP technology was selected for this rehabilitation project. Pro-liner delivered an integrated one-stop solution covering liners, UV Curing System and professional technical services.

· Liners: Independently developed DN1800×18mm extra-large-diameter and wall Thickness UV-CIPP liner. Its load-bearing capacity was multiple times higher than conventional polyester felt liners. It achieved equivalent structural strength with reduced wall thickness to preserve maximum internal flow cross-section.

· Equipment: Full-process support by Pro-liner UV curing system, featuring real-time control over light train travel speed, multi-point temperature and internal pressure, delivering stable high-power curing performance.