The tower is a cylindrical welding structure of the process equipment, consisting of a shell, head (or cover) and a support. It is used in distillation, absorption and extraction to complete heat and mass transfer process in chemical industry.

According to its structure can be divided into two kinds: plate tower and packed tower.

It is often used with bubble tower, packing tower, thick plate tower, flood tower, floating valve tower, keittel tower, shaped tower (S tower), tongue tower, circulating plate tower, rotary tray tower, guide sieve plate tower, etc.