Abstract: System for recirculating hydrogen in a fuel cell including a tank having an inlet connectable to an outlet of the fuel cell and an outlet connectable to a line for feeding hydrogen to the fuel cell; the recirculation system includes a first check valve and a second check valve; the first check valve can be inserted between the outlet of the fuel cell and the inlet of the tank, for adjusting a flow from the fuel cell to the tank whilst the second check valve can be inserted between the outlet of the tank and the hydrogen feed line, for adjusting a flow of hydrogen from the tank to the feed line.

Abstract: A mechanical arrangement comprises a housing (10) arranged to receive an elongate member (11) which is mounted within the housing for reciprocation, the elongate member having an extension (11a) projecting outside the housing to form an output member, wherein the elongate member is formed with a shaped aperture (18) which receives an electrically actuated blocking member (19) which controls the stroke of the elongate member as it is moved towards and away from the elongate member in a direction transverse to the direction of reciprocation.

Abstract: A bistable actuator for residual-current devices, including a lamina having at least one face, a first end, and a second end, and configured to actuate from a first stable position to a second stable position; at least one layer of piezoelectric material provided on the at least one face of the lamina at the first end of the lamina, and configured to stimulate the lamina to shift from the first stable position to the second stable position in response to an electrical activation signal; and a support element including an interlock coupling, and configured to support the first end and the second end of the lamina, wherein the interlock coupling is configured to interlock the first end of the lamina to the support element, and the second end of the lamina is rigidly coupled to the support element in order to keep the lamina in the first stable position.