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Difference of Pipe and Tube

Posted on 01 November 2020 by Admin

The terms pipe and tube are often confused, although they both have the same function to flow fluids, pipes and tubes have very different characteristics. Pipes are identified by NB, nominal bore, which is a measure used to describe the diameter of a pipe. What is usually the NB size (some call it ND, nominal diameter or NPS, nominal pipe size) is not necessarily the same as the OD of the actual pipe size. While tubes, identified with OD are usually the same size for all sizes.

What are pipes?

Each pipe has a uniform OD size, which is usually identified with NPS while only the thickness (schedule) is different. For pipes below 12 inc, the NPS size is larger than the OD, while above (14 in and above) the NPS size is exactly the same as the OD. Usually stay multiply the NPS by 25.4 mm as converter to in.

What are tubes?

As for the tube, the tube is a cylindrical object that has a hole in the middle to drain the fluid. Unlike pipes, tubes are relatively small in size and are not limited by a spool (a certain length such as pipes, generally 6 meters). In addition, tubes are more flexible and easier to shape or bend than pipes.

If the same is used to flow fluid, where is the tube needed? Tubes are usually used for instrument equipment. More specifically, tubes are used to drain fluid in the heat exchanger. The fluid that is flowed in the tube will usually be increased or heated with other fluids in HE.

In terms of size, tubes are measured in OD. Unlike the pipe which has an OD that is not the same as the NPS, the measuring tube is used OD and the thickness is measured in a unit of thickness known as bwg. In contrast to pipes that are made with large sizes, tubes are made small in size but many. The goal is to expand the contact surface with other fluids, so that later the heat exchange is more effective.

The large tube size has the advantage of being easier to clean, besides being hard. As for the small tube size, it has a greater advantage in heat transversion because of its high heat-transfer efficiency.

The tubes on the heat exchanger have an Outside diameter of ¼ in (6.35mm) to 2 in (5.8 mm). The available OD tubes are ¼, 3/8, ½, 5/8, 3/4, 7/8, 1, 1 ¼, 1 ½ and 2 in. As for the size of the tube thickness, it is known as bwg. Bwg is the size for tube thickness used by TEMA (tubular exchanger manufacturers association), BWG itself stands for birmingharm wire gauge.

Because it is intended for heat transfer, usually these tubes will be arranged in such a way as to follow a certain pattern, so that the heat transfer process is effective. Like pipes, tubes also consist of tubes that have a connection, some are seamless tubes. For welded tubes, it is usually made of strip material which is then rolled into sylindrical and then welded.

As for the extruded or drawn seamless tubes using hot working. Generally, the types of tubes on the market consist of either seamless (without welding) or with welds, only for copper type tubes and copper alloys which only exist in seamless types. with this, hopefully you will understand more about the difference between pipe and tube.