US Patent 7712725 Drain valve assembly

A drain valve assembly having a stem which can be inserted into a crankcase or other fluid reservoir, wherein the stem is connected to a housing which encloses a sealing barrel movably secured and sealed in the connected stem and housing, and wherein the sealing barrel can be manipulated in a single direction from the exterior of the assembly to open or close a fluid passage through the assembly. An end cap may also be provided tethered to the housing for sealing off the fluid passage. Selected movement of the sealing barrel in the connected stem and housing may also be used to control the volume and flow of fluid through the fluid passage.