How does a bottle trap work?

The bottle trap is a kind of a deep vessel which has a bigger diameter than the plumbing pipe. The plumbing pipe that comes from the basin goes straight into the bottle trap.

When more water gushes in the water inside the bottle trap goes into the drain and fills with the new water that comes from the waste. Thus the trap always remains filled with a certain amount of water and the pipe from the basin remains immersed into this water inside the bottle trap.

Now when the sewer gases re enter the system through the outlet pipes they reach the bottle trap, but here they find their way sealed with the water that is collected in the trap. Due to the basin pipe immersed in water it remains closed and doesn’t allow the return waste and gases to enter it and pave their way upwards into and out of the basin right into the bathroom.