Abstract: A check valve which allows a sub valve body to have an improved sealing function when the check valve has an increased size. When a sub valve body 300 is seated on a second valve seat 231 and a third valve seat 440, S2?1 is satisfied where a seal area S1 is a total of a contact area of the sub valve body 300 and the second valve seat 231 and a contact area of the sub valve body 300 and the third valve seat 440, and a pressure-receiving area S2 is an area of a non-contact region at a lower end surface of the sub valve body 300 between a contact region of the sub valve body 300 and the second valve seat 231 and a contact region of the sub valve body 300 and the third valve seat 440.

Abstract: A heat insulation structure and a liquid supply system that can prevent breakage of a heat insulation member while providing satisfactory heat insulation. The heat insulation structure includes heat insulation members 520 provided between two components and having heat conductivity lower than the two components and a slidable member 530 slidable on the heat insulation member 520. At least two of the heat insulation members 520 are arranged along the direction of compression by the two components, and at least one of the slidable member 530 is disposed between the heat insulation members which are adjacent to each other. The heat insulation members 520 and the slidable member 530 are allowed to be displaced in directions perpendicular to the direction of compression.