Effort-saving flap-type drain valve

An effort-saving flap-type drain valve, comprising:

• a base with a drain port;
• a flapper capable of hermetically covering and connecting to the drain port;
• an actuator connected to the flapper;
• and
• a connecting rod rotationally connected to the base and the flapper at two ends respectively;
• wherein in a state where the flapper hermetically covers and connects to the drain port, as the actuator is driven, the actuator is capable of causing the flapper to rotate relative to the connecting rod, and the actuator is capable of simultaneously causing the flapper to rotate about a first rotation pivot formed at a position where the flapper is in contact with the base to initially open the drain port;
• and in a state where the drain port is initially opened, the actuator is capable of causing the flapper and the connecting rod to rotate together about a second rotation pivot formed at a rotational connection between the connecting rod and the base to further open the drain port.