Currently pipeline maintenance and repair is divided into stopping transmission repair and transmission repair stop, for example, in the oil and gas pipeline network developed in North America, the same line pipe network composed by a few pipes, pipe network can be achieved in one of pipeline shutdown in a planned mend, which is generally carried out in these pipes is to stop transmission repair. There are some requirements for pipeline transportation pipeline because the body is not suitable for intermittent or transport, according to local conditions, which requires us to be constantly lose fixed. In China, the pipeline mend methods are also fairly with foreign developed level. However, in general, is the most used way to stop transmission repair. Pipeline repair methods to some extent, also determines the pipeline repair methods, typically using ditch outside repair is needed to stop the pipeline, but from an economic sense, than the trench ditch outside repair costs low.
In the pipeline repair methods are generally divided into inner and outer repair method. PE pipe insertion method, pipe lining method and the soft inner liner mend method is turning more common approach. Within the repair method is generally applicable for low pressure gas pipes, water pipes, gas pipes or sewers, etc., in the mend of civilian facilities is relatively common. As for the high, medium pressure gas pipeline more common is the use of foreign repair method fixes. Repair can be divided into the outer tube defect mend and reinforcement pipeline coating mend. Currently used methods of reinforcing tube defects patched, patching, full circle sleeve, half sleeve, composites mend, epoxy filler fix sleeve. Which patched tube replacement method, the metal fixtures in the domestic pipeline repair method is widely used in epoxy composites filled sleeve and fix of new technology in the country a few years ago, is currently in China on land, at sea oil and gas pipeline repair has been widely used.
Pipeline repair coating material required to have chemical and physical properties of indicators such as many, such as water resistance, electric insulation, adhesion and so on. In the restoration project, the original pipe coating type, geographical location, re-coating method, the coating of the applicable conditions, pipeline operating conditions, and cost are all factors that need to be considered coating selection, pipe surface pretreatment conditions, repeated cycle, the application of the device complexity, backfill time, old and new chemical compatibility of coating material determines the success or failure of the pipeline repair, so select the appropriate materials fix the pipeline fix a key part. Polyurethane and epoxy coatings are currently in the pipeline fix the most widely used material. Polyurethane coatings with good mechanical properties and fast curing characteristics, and a wide range of epoxy coating surface tolerance and at a relatively low film thickness, can all play a very good protection. Other coatings include coal tar enamel, cold polyolefin tape, FBE and the wax coating and tape coating.