Patent ID: 7695445

Claim:
A three-way stopcock, comprising: a substantially cylindrical shaped body having first through third branch openings on a periphery thereof, the first branch opening and the second branch opening being situated at respective opposite sides of a cylindrical periphery of the body and the third branch opening being situated between the first and second branch openings away therefrom at right angles; and a flow passage switching portion that is mounted in a cylindrical bore of the body so as to be rotatable around an axis of the cylindrical bore with respect to the body and to have liquid-tightness, and has flow passage bores that form fluid flow passages so as to allow communication between predetermined branch openings, wherein the fluid flow passages can be changed by rotating the flow passage switching portion with respect to the body, wherein the flow passage bores comprise a first flow passage bore for forming a first fluid flow passage from the first branch opening to the third branch opening and a second flow passage bore for forming a second fluid flow passage from the second branch opening to the third branch opening in a path separated from the first flow passage bore, both ends of the first and second flow passage bores form flow passage openings at a peripheral surface of the flow passage switching portion, the flow passage openings being separated from each other at the peripheral surface of the flow passage switching portion, two of the flow passage openings corresponding to the third branch opening are located adjacently and aligned along a direction parallel to the axis of the cylindrical bore, and when a relative angular position of the cylindrical body and the flow passage switching portion are set at a predetermined state, the first flow passage bore and the second flow passage bore are arranged to form the first fluid flow passage and the second fluid flow passage, respectively, at the same time, and the adjacent two flow passage openings confront the third branch opening.