The semi-circular coil jacket is an efficient heat transfer element. Compared with other forms of jacket, the heat transfer efficiency is high; compared with the inner coil, there is no risk of mixing with the medium in the tank after the leakage of the coil, so it is often used in occasions where the purity of the medium is relatively high.

Semi-circular coils are limited to use seamless tubes with outer diameters of 60, 89, 114mm, suitable for vessels with a diameter of 760~4300mm, and a cylinder or head thickness of 4.5~50mm.

When the semicircular coil jacket is arranged on the shell, its pitch can be determined according to the needs of the heat transfer process and the welding process, and has nothing to do with the strength and rigidity of the shell. Therefore, the semicircular coil jacket does not need to calculate the external pressure, and it has a certain strengthening support for the kettle body.