Maintenance-free moisture absorption device for transformer

The maintenance-free moisture absorption device comprises a moisture absorber and a control box, the moisture absorber comprises an upper support, a lower support, a fixing sleeve and a connecting flange, an upper air hole is formed in the upper support, lower air holes are formed in the lower support, the fixing sleeve comprises a cylindrical shell and an inner net which are sleeved with each other, and an inner cavity and an outer cavity are formed in the shell; the upper support and the lower support are coaxially arranged at the upper end and the lower end of the fixing sleeve respectively and clamp and fix the fixing sleeve, so that the lower air hole, the inner cavity, the outer cavity and the upper air hole are communicated, the inner cavity is filled with moisture absorption materials, the upper air hole is coaxially connected with the connecting flange, and a heating piece and a temperature and humidity sensor are arranged in the inner cavity. A pressure sensor and an airflow sensor are arranged on t