Abstract text

A main drain of a swimming pool has a housing, a removable cover, and one elongated opening formed therein. In one embodiment, the housing is oval in shape with the elongated opening running parallel to the major dimension of the housing to provide a single extended opening that would be difficult for a swimmer to obstruct. In an alternative embodiment, the elongated opening extends over a round cover and is H-shaped. Each elongated opening is formed to have an internally curved flange to provide a smooth edge and structural stiffness for the cover. The single extended opening with its smooth, rounded edges reduces the likelihood of entrapment and entanglement and allows large debris, such as leaves, to pass more easily into the main drain.