Structure of external cover of air drying apparatus

A structure of an external cover of an air drying apparatus, the structure comprising:

• an outer case;
• a base housed in the outer case and including a large-diameter cylindrical body;
• a small-diameter cylindrical body formed integrally with the large-diameter cylindrical body;
• a drying case including a desiccant filled in the large-diameter cylindrical body, the base being fixed to a lower end of the drying case and including an inlet port and an outlet port for compressed air, the base being fixed by swaging an outer edge thereof to a lower end of the outer case, wherein the external cover includes:
• a rising piece inserted into and engaged with the inlet port of the base for compressed air;
• a first slope formed at an intermediate position between the rising piece and a bottom;
• an outer vertical wall formed so as to rise from the bottom;
• a top face formed at an upper end of the outer vertical wall;
• an inner vertical wall formed opposite to the outer vertical wall;
• a circular-arc portion formed at a lower end of the inner vertical wall;
• a second slope formed at a position on the circular-arc portion that corresponds to an intermediate position of a height of the external cover and a position of a predetermined height from a lower end face;
• an outermost vertical wall formed so as to fall from the second slope by way of the circular-arc position, an angle of inclination between a back surface of the second slope and a back surface of the outermost vertical wall is about 45°;
• and
• a sealing agent fitted to an indentation defined by the outer vertical wall, the top face, and the inner vertical wall.