Water closet comprising variable soil exhaust system

A water closet, comprising:

• a variable siphon soil exhaust system including:
• a flexible water bladder installed at a rear side of a bowl to be connected to a water supply passage, a tension spring for applying an elastic force to contract the water bladder, a variable siphon tube connected to the water bladder via a bracket to allow soil to be exhausted from the bowl while lifted and lowered by an expanding and contracting motion of the water bladder, and a small tube for connecting the water bladder to the variable siphon tube;
• and
• a cover installed to surround the soil exhaust system,
• wherein the cover is formed by coupling first and second half covers having the same shape and comprises a first port connected to the water supply passage, a second port connected to the bowl, and a third port connected to a bottom tube laid under the floor;
• the variable siphon tube has one end connected to the bowl through a bellows tube and an open opposite end disconnected from the bottom tube and freely movable in horizontal and vertical directions within the interior of the cover;
• and the tension spring is installed with an upper end thereof fixed to an upper catching portion installed at an outlet of the water supply passage and a lower end thereof is fixed to a lower catching portion provided on the bracket or a bottom surface of the water bladder.