Connection device (10) for fluid circuits, the device (10) being arranged to hydraulically connect two adjacent circuit sections (C, C') and, if necessary, to allow disconnection of the two circuit sections (C, C') under load without causing fluid losses from the circuit, the device (10) comprises moreover two thermal expansion valves (12, 12') releasably connected directly to each other, each valve (12, 12') being configured to be mounted to an end of a respective circuit section (C, C') and being shiftable between an open position and a closed position, in which it allows and prevents fluid flow through the device (10), respectively, depending on the fluid temperature.