Patent ID: 8707997

Claim:
A fluid device unit structure comprising: a plurality of fluid devices including first and second valves; a base member defining flow paths including a main fluid flow path and a return flow path that are respectively provided to interconnect the valves, wherein a position at which the return flow path branches from the main fluid flow path is close to an input of the first valve and extends to an input of the second valve, wherein the base member is monolithic and the position minimizes a stagnant flow area adjacent the input of the first valve when the first valve is closed, wherein the main fluid flow path includes: a horizontal flow path section that laterally extends from an inlet connection port provided on a side surface of the base member, and a vertical flow path section that extends vertically upward from the horizontal flow path section, wherein the return flow path has a sloping flow path section that communicates with the vertical flow path section so as to intersect therewith, wherein the sloping flow path section is a flow path branching upward at an incline from a branching inlet that is opened in the vertical flow path section, and the sloping flow path section communicates with a valve chamber of the second view.