Trap-type drain with built-in strainer

Claim 1

A drain trap comprising: an upwardly open four-sided outer vessel with a closed bottom, one side of said outer vessel being provided with a lateral outlet extending from said bottom to a high point close to an upper rim thereof; a partition parallel to said one side in said outer vessel rising from the bottom thereof and having an overflow edge at a level below said high point, said partition dividing the interior of said outer vessel into a first compartment remote from and a second compartment proximal to said outlet; and an open-topped insert suspended by a closely fitting collar from said rim in sealed relationship with said outer vessel while terminating above the bottom thereof, said insert extending below said level into said first compartment and forming a downwardly converging, generally frustopyramidal closed-bottom inner vessel with a solid wall spacedly confronting said partition and with three other walls having peripheral apertures in the vicinity of said level, said insert further forming a skirt depending from said collar while spacedly surrounding said three other walls and defining therewith a laterally closed but downwardly open chamber while leaving said solid wall exposed, said partition enabling liquid issuing from said apertures to escape into said outlet across said overflow edge while accompanying solids are retained in an imperforate lower part of said inner vessel.