Air-cooled COD (Chemical Oxygen Demand) digester

The utility model provides an air-cooled COD (Chemical Oxygen Demand) digester. The air-cooled COD digester comprises a bottom plate, the sliding rods are fixedly installed on the periphery of the top of the bottom plate, sliding sleeves are slidably connected to the outer side faces of the sliding rods, and a heating plate is fixedly installed on one sides of the sliding sleeves; and the mounting groove is formed in the top of the bottom plate, a driving motor is fixedly mounted at the bottom of the inner side face of the mounting groove, a threaded sleeve is fixedly mounted at the output end of the driving motor, and the inner side face of the threaded sleeve is in threaded connection with a threaded rod. According to the air-cooled COD digester provided by the utility model, the heating plate is driven to move up and down through the rotation of the driving motor, and then the conical flask is driven to move up and down, so that when a user takes down and installs the conical flask, the conical flask can b