Automatic drain discharge apparatus

An automatic drain discharge apparatus comprising:

• a case including an opening at a bottom of the case;
• a first housing provided in the opening, and including a drain discharge hole;
• a drain valve seat provided in the drain discharge hole;
• a drain valve plug configured to open/close the drain valve seat;
• a float movable vertically in accordance with a liquid level of drain in the case;
• and
• a pilot valve configured to apply pilot pressure to a diaphragm by vertical movement of the float in order to drive the drain valve plug,
• wherein an inner diameter at the bottom of the case is gradually decreased from upper to lower positions;
• the first housing includes a communication hole configured to allow an inside of the case to communicate with the drain discharge hole;
• a bottom surface of the communication hole includes an inclined surface inclined toward the drain discharge hole;
• and
• the bottom surface of the communication hole and an inner circumferential surface of the case form a continuous surface, or an uppermost position in the bottom surface of the communication hole is lower than a lowermost position in the inner circumferential surface of the case and adjacent to the opening.