SPR™-ST rehabilitation process.

SPR™-ST Rehabilitation Process

Spiral winding rehabilitation processes can be categorized in various ways depending on the construction method and the profiles selected.

For instance, they can be classified into the fixed-diameter method and the expansion method based on whether the diameter of the resulting liner pipe changes; they can also be categorized as stationary or self-propelled based on the mobility of the winding equipment. Each method offers distinct advantages.

SPR™-ST Rehabilitation Process.

The primary liner material (PVC strip) and an outer steel strip (which provides added strength) are fed into specialized winding equipment installed at the bottom of the manhole. The equipment joins the PVC profiles to form a sealed liner pipe, while the steel strip is embedded on the exterior of the liner to reinforce structural strength.

Upon completion of the winding process, a gap remains between the new liner and the old pipe; cement grout is injected into this space to create a solid bond between the liner and the host pipe.

Its unique advantages include:

Capability for wet-condition operations: Suitable for pipelines where complete dewatering is not feasible.

No excavation required; minimal footprint and noise; interruptible construction process; quiet operation with flexible mobility.

Adaptability to harsh underground environments: The use of specialized steel strip materials effectively ensures the structural strength of the wound pipe. "T"-shaped ribs and male-female interlocking edges on the PVC profiles effectively enhance both the material's structural strength and the sealing integrity of the resulting liner.

Three types of PVC profiles are currently in use: 91-25-PVC1, 126-15-PVC1, and 126-20-PVC1 (where 91 and 126 represent the PVC strip width, and 25, 15, and 20 represent the height of the "T"-shaped rib). Steel strip dimensions vary according to the profile used. Within a given unit length of the liner, using a narrower PVC strip results in a higher number of embedded steel strip coils at the interlocking joints; a greater number of coils translates to higher structural strength for the liner (the steel strip thickness can also be increased based on design requirements, up to a maximum of 1.5 mm). When selecting materials for spiral wound repair, the appropriate profiles and steel strips must be calculated and chosen based on factors such as the pipeline's burial depth, load-bearing capacity, and structural strength requirements.