Fluid control system, base block used for same, and method for manufacturing fluid control system

A fluid control system comprising:

• a fluid device provided with a body defining a body fluid flow path through which fluid can flow in a fluid flow direction from upstream to downstream, the body fluid flow path comprising two body flow path ports that open at a bottom surface of the body;
• an upstream-side base block and a downstream-side base block, the downstream-side base block positioned downstream of the upstream-side base block in the fluid flow direction;
• and
• a coupling base block, wherein:
• the upstream-side and downstream-side base blocks each:
• define an upper surface on which a portion of the body of the fluid device is installed, a bottom surface opposite to the upper surface, and side surfaces extending from the upper surface toward the bottom surface side,
• define a fluid flow path comprising two block flow path ports that open on an upstream side and a downstream side of the upper surface, and
• comprise a screw hole that is formed between the two block flow path ports, opens at the upper surface, and extends toward the bottom surface side;
• the upstream-side and downstream-side base blocks and the body of the fluid device are coupled by tightening forces of tightening bolts passed through the body of the fluid device and screwed into the screw holes of the upstream-side and downstream-side base blocks;
• a seal disposed around each of the two body flow path ports of the fluid device respectively abutted against the block flow path port on the downstream side of the upstream-side base block and the block flow path port on the upstream side of the downstream-side base block and pressed between the upstream-side and downstream-side base blocks and the body of the fluid device, wherein
• the upstream-side base block and the downstream-side base block are disposed apart from each other;
• and
• the coupling base block is coupled to a downstream-side end portion of the upstream-side base block and an upstream-side end portion of the downstream-side base block by tightening bolts, such that the upstream-side base block and the downstream-side base block are coupled together.