A213T12 ASTM A213 Tubing Steel Carbon Pipe Customized

Types of heat exchanger tubes
The heat exchange tube is one of the elements of the heat exchanger, which is placed in the cylinder and used for heat exchange between the two media. Has high thermal conductivity and good isothermal properties. It is a device that can quickly transfer heat energy from one point to another with almost no heat loss, so it is called a heat transfer superconductor, and its thermal conductivity is thousands of times that of copper.

Form
In addition to plain tubes, heat exchangers can also use a variety of enhanced heat transfer tubes, such as finned tubes, threaded tubes, spiral grooved tubes, etc. When the heat transfer coefficient on both sides of the inner diameter of the tube has a large difference, the fins of the finned tube should be arranged on the side with the lower heat transfer coefficient.

Size
The commonly used dimensions of heat exchange tubes (outer diameter x wall thickness) are mainly Φ19mmx2mm, Φ25mmx2.5mm and Φ38mmx2.5mm seamless steel pipes and Φ25mmx2mm and Φ38mmx2.5mm stainless steel pipes. Standard pipe lengths are 1.5, 2.0, 3.0, 4.5, 6.0, 9.0m, etc. The use of small pipe diameter can increase the heat transfer area per unit volume, the structure is compact, the metal consumption is reduced, and the heat transfer coefficient is improved. It is estimated that by changing the heat exchange tube of the same diameter heat exchanger from Φ25mm to Φ19mm, the heat transfer area can be increased by about 40%, and the metal can be saved by more than 20%. However, the small diameter of the pipe has large fluid resistance, which is inconvenient to clean and easy to scale and block. Generally, large diameter pipes are used for viscous or dirty fluids, and small diameter pipes are used for cleaner fluids.

Material
Commonly used materials are carbon steel, low alloy steel, stainless steel, copper, copper-nickel alloy, aluminum alloy, titanium, etc. In addition, there are some non-metallic materials, such as graphite, ceramics, polytetrafluoroethylene, etc. In the design, appropriate materials should be selected according to the working pressure, temperature and corrosiveness of the medium.

Center distance
The arrangement of heat exchange tubes on the tube sheet mainly includes equilateral triangle, square and corner equilateral triangle and corner square. The equilateral triangle arrangement can arrange the maximum number of tubes on the same tube sheet area, so it is most commonly used, but it is not easy to clean the outside of the tube. To facilitate cleaning outside the tubes, tube bundles in a square or corner square arrangement can be used. The center distance of the heat exchange tube should ensure that the tube bridge (clearance distance between two adjacent tubes) has sufficient strength and width when the tube is connected to the tube sheet. When cleaning is required between the tubes, a channel for cleaning should also be reserved. The center distance of the heat exchange tubes should not be less than 1.25 times the outer diameter of the heat exchange tubes. The most commonly used center distances of the heat exchange tubes are as follows. Commonly used heat exchange tube center distance (mm).