Connection Modes of Oil Pipelines

Several days ago, we introduced the types of tube that used in oil pipeline, today, we will share the connection modes of oil pipelines for people those interested in this aspect.

Oil pipeline must use a certain connection to form a complete system. Connection methods of pipeline are mainly three categories, including screw thread, welding and flange connection.

When the pressure is not high, the pipe with small diameter can be connected by using screw thread this method. This connection method is very convenient, but most of the diameter of oil pipelines are generally larger, so other two connection methods are used commonly.

The pipeline that DN≥50 basically uses welding method to connect. Welding has many advantages, such as convenient construction, strong, tight and saving steels. The general straight pipe or bends those parts do not need to tear down can use this method.

The connection of pipes and valves or other equipment (such as: pump) and the parts those need to disassemble of pipeline need to use flange to connect. In order to ensure the tightness of the flange connection, we also need to use a relatively soft flange grommet to assist on both sides of the flange. According to the production process, flange can be divided into flat welding, thread, butt welding, loose tube and blind plate and other types. Except blind plate flange, others are all used in interconnection between the pipeline. If you need to connect different diameters of the pipeline, you can use the adapter flange that two diameter corresponding. The blind plate flange is used to close the end of the pipe head. Therefore design of it make it can withstand greater bending stresses.

What type of tube is used in Oil pipeline?

The tube that used in Oil pipeline is mainly carbon steel pipe, according to its manufacturing process, it can be divided into seamless steel pipe and welded steel pipe.

Seamless steel pipe has the characteristics of high strength, specifications and more features, so it is applicable to transport strong corrosive oil or transport in the high temperature conditions. The technology of seamless steel pipe is divided into hot rolling and cold drawn. As the cold drawing process will cause the material hardening, it also needs to do the corresponding heat treatment based on the specific use of pipe.

Welded steel pipe can be divided into two kinds, straight seam steel pipes (LSAW steel pipe) and spiral welded pipe (SSAW steel pipe). The process characteristics of carbon steel pipe leds the steel pipe to tend to become brittle at low temperatures, so it is mainly applied to the normal temperature pipeline, the use of pipe temperature should not exceed 300 degrees Celsius. In general, the temperature of ordinary carbon steel pipe is between 0 to 300 degrees Celsius. If using the high-quality carbon steel pipe, the temperature range can be broadened from -40 to 450 degrees Celsius. The experimental pressure of the steel pipe is generally 1.5 times of the nominal pressure. When the temperature of the material delivered does not exceed 200 degrees Celsius, the working pressure is the nominal pressure. When the temperature exceeds 200 degrees Celsius, the working pressure should be correspondingly lower than the nominal pressure.