You searched for: “inverted siphon
inverted siphon
Although not a "true siphon", the term is applied to pipes that must dip below an obstruction to form a U shaped flow path.

Inverted siphons are commonly called "traps" for their function in preventing smelly sewer gases from coming back out of drains and sometimes making solid objects; such as, rings recoverable after falling into a drain.

This entry is located in the following unit: siphon-, siphono- + (page 1)