Manually closable anti-backup trap

Abstract

A trap for a drain has a housing with a lateral exit port for water flowing in through an apertured lid and/or through a lateral entrance port. A tubular insert fitted to the sidewall with the exit port has a bottom inlet beneath the level of that port and a side outlet provided with a check valve in the form of a hinged flap swinging outwardly into the exit port. In one embodiment, the flap comes to rest on the broad end of a frustoconical shutter rotatably seated in the upper end of the insert which is separated by a correspondingly curved partition from the lower end; the shutter and the partition have apertures which normally register with each other but can be disaligned by a rotation of the shutter about a horizontal axis with the aid of a handle secured to it inside the housing and accessible upon removal of the lid. In another embodiment, a similarly accessible handwheel atop the insert has a tubular shaft threadedly engaging a vertical leadscrew rising from a shutter disk which lies between the bottom opening and a horizontal partition having an aperture that is closable by the disk from below.

Dependencies are inferred from the claim text.