1. Type A Sleeves (Reinforcing)
This type of Sleeve is not is used only for non-leaking defects installed on a pipeline without welding
2. (Type B Sleeves) Pressure Containing or Capable of Containing Pressure
The other type of steel sleeve used to make pipeline repairs is known as a Type B sleeve. The ends of a Type B sleeve are fillet welded to the carrier pipe.
3. Defect Repair Using Composite Reinforcement Sleeves
Composite materials have been used in aerospace structural applications for many years. In recent years, composite sleeves have been developed and used for the repair of non-leaking pipeline defects. The various composite sleeves are proprietary products produced by specific vendors. The rigid materials are limited to relatively straight sections of pipe much as steel sleeves. The flexible materials can be applied to bends, elbows, and tees.
The advantages of composite reinforcements compared with steel sleeves are easier handling of the materials, lower skill requirements for installation personnel, more rapid installation, and lower overall cost.
4. Mechanical Clamps
Several types of mechanical clamps are available from various commercial vendors. Figure 24 shows a photograph of a typical bolt-on clamp.
A leak clamp is used to repair a leaking external corrosion pit. It consists of relatively lightweight metal bands with a single draw bolt to tighten it onto the pipe. Figure shows a typical leak clamp.
The clamp has a threaded fitting located 180 degrees from the draw bolt.
5. Hot Tapping
Hot Tapping is a means by which access is made to the inside of an operational pipeline, using either a drill or a circular cutter. Applications include attachment of a branch connection to the line, installation of an internal probe or monitor, and to stop or redirect flow in a line for maintenance or repair purposes.
A plugging system which is designed to stop flow through a line while equipment installation, maintenance work or repairs are being made. A plugging head is inserted into the line through a fitting and flow is stopped and/or redirected through bypass piping.
A plugging (Stopple) machine is used to temporarily stop the product in an operating pipeline, by acting as a block valve. When used in conjunction with a bypass line and another plugging machine, product can be rerouted around the isolated section of pipeline, while repairs, alterations, relocations and instrument installations are made to the piping system.