Drain socket and flush toilet

A drain socket for connecting an outlet of a trap drainage channel of a flush toilet unit and a drain pipe located external of the flush toilet unit, said drain socket comprising:

• a drain socket body provided with an inlet for coupling with the trap drainage channel and an outlet for coupling with the drain pipe;
• a channel contraction section provided in a channel of the drain socket body;
• a guide groove provided on a downstream side of the channel contraction section continuously in a water flow direction;
• and
• the entire channel in the drain socket body having an inside diameter equal to or larger than the inside diameter of the outlet of the trap drainage channel.

A drain socket to be arranged to connect an outlet of a trap drainage channel of a flush toilet unit and a drain pipe located external of the flush toilet unit whose center is eccentrically located with respect to the center of the outlet of the trap drainage channel, said drain socket comprising:

• an inlet for coupling with the outlet of the trap drainage channel;
• a channel expansion section having an inside diameter expanding toward a downstream side from the inlet;
• a deflector plate extending in an inward direction from an inner wall of the channel expansion section;
• a siphon inducing shelf formed at a downstream end of the channel expansion section to extend at least on the side in the direction opposite from the direction of eccentricity;
• and
• a bent pipe that extends from the downstream end of the channel expansion section and whose downstream end couples with the drain pipe.