Strengthening corroded pipe walls with sealer sleeves
One of the most common reasons why there is a need for gas internal pipe repair is corrosion which can compromise the wall thickness of pipes. In order to prevent rupture on the corroded area, the pipe must be reinforced. Most of the pipe repairs that can be done outside can also be applied inside the home but it is more desirable if the pipes are taken out of service while the process of internal pipe repair is being undertaken. The most common method used in internal pipe repair is the installation of a welded full encirclement steel repair sleeve that resists hoop stress. If the ends will be welded on the pipeline, it can resist axial stresses. Sealer sleeves can seal cast iron and low pressure mains that will eliminate pipe replacements. The pipe walls that have been subjected to corrosion will be strengthened with minimal disruption to the property.
Fiber reinforced composite repairs
An alternative to the installation of sealer sleeves to strengthen pipes that have been corroded is the use of fibers for reinforcement. The repair is undertaken through the use of glass fibers in a polymer matrix material that is bonded to the pipe using an adhesive. The adhesive filler is applied to the defective part prior to installation to allow load transfer to the composite material. A variety of liners are often used for the repair of internal pipes that include sectional liners, cured-in place liners and fod-and-formed liners.
Sectional liners are typically available in 3-foot to 15-foot lengths and can be installed in areas that need repair. Both the cured-in-place and fod-and-formed liners are applied in the entire pipe segment. Cured-in place liners are installed through the inversion process while the fod-and-formed liners are pulled into place before inversion so that they can fit tightly against the inside of the pipe. In addition to the advantages of repair, if liners are continuously applied, they can increase the operating pressure of the existing pipeline.
Ways to apply a liner into the pipe
In the first process of liner installation into pipes, it is pulled using a cable to the precise location so that the pre-cut connections will line up where the incoming pipes are. The second process of liner installation is through “invert” or “shoot” it into pipe. The liner is rolled into the tank that has a gun barrel sticking out of it. When the tank is pressurized with air, the front ends of the liner that is sticking out of the barrel and has been wrapped on the outside of the barrel will shoot the liner into place while the liner inverts.