A filter system with flow regulation includes a filter interposed along the fluid passageway and a differential valve in fluid series therewith. The valve may use the upstream reference hydraulic pressure at the filter inlet and a downstream hydraulic pressure thereof to generate a valve position that regulates fluid flow along the fluid passageway. This can partially restrict flow and reduce pressure differential across the filter system and effectively closes off flow through the system when pressure differential is high. This may be used in aircraft or other fueling applications to limit flow and cause the operator to change the fuel filter once fuel flow slows to a trickle when the differential valve effectively closes due to higher differential pressure. The valve is also capable of a fully closed position at high pressure differential state.

A dual lock flow gate includes a valve with a flapper which may be fixed and/or locked in various positions.

Fuel tank inerting systems and methods for aircraft are described. The systems and methods include controlling of (i) a first reactant control element, (ii) a second reactant control valve, (iii) a ram air control valve, (iv) a driving mechanism, and (v) a flow control valve, to control a state of a fuel tank inerting system. The states of the fuel tank inerting system include an OFF state, a CIRCULATE state, a PRIME state, a CATWARM state, an ON state, a DEPRESSURIZE state, and a COOLDOWN state, wherein the states are determined in part by a prior state and/or a position/actuation of a given element of the system.

Fuel tank inerting systems and methods for aircraft are described. The systems and methods include controlling of (i) a first reactant control element, (ii) a second reactant control valve, (iii) a ram air control valve, (iv) a driving mechanism, and (v) a flow control valve, to control a state of a fuel tank inerting system. The states of the fuel tank inerting system include an OFF state, a CIRCULATE state, a PRIME state, a CATWARM state, an ON state, a DEPRESSURIZE state, and a COOLDOWN state, wherein the states are determined in part by a prior state and/or a position/actuation of a given element of the system.

A fuel extraction system for extracting a gaseous fuel from a fuel tank. The fuel extraction system includes a conveying device which is configured to convey gaseous fuel and to bring it from a first pressure level to a second pressure level, a first line which is configured to connect the conveying device fluidically to the interior of the fuel tank, a buffer tank which is configured to store the fuel at the second pressure level, and which has a first outlet and a second outlet, at least one valve with a pneumatic actuating device, and a second line which is connected to the first outlet of the buffer tank and is configured to conduct a part of the fuel at the second pressure level to the pneumatic actuating device of the at least one valve. Furthermore, a fuel tank apparatus and a fuel cell system are described.

A liquid tank system comprises a main liquid tank, an outlet communicating between a fluid circuit and the main liquid tank, an inlet communicating between the fluid circuit and the main liquid tank, and an auxiliary cavity. First vent passage and second vent passage(s) communicate between the main liquid tank and the auxiliary cavity and allows liquid and gas to flow from the main liquid tank to the auxiliary cavity. The second vent passage has a flow control device regulating flow through the second vent passage and having a set point at which it allows liquid and gas to flow from the main liquid tank to the auxiliary cavity only when a pressure in the main liquid tank is beyond a threshold. The liquid tank system has an attitude envelope in which the liquid tank system is configured such that, in use, the flow control device blocks flow through the second vent passage when an end of the first vent passage in the main liquid tank is above a liquid level, and the flow control device allows gas and/or fluid flow through the second vent passage when main fluid tank pressure is above the threshold and the end of the first vent passage in the main liquid tank is below the liquid level.

A liquid tank system comprises a main liquid tank, an outlet communicating between a fluid circuit and the main liquid tank, an inlet communicating between the fluid circuit and the main liquid tank, and an auxiliary cavity. First vent passage and second vent passage(s) communicate between the main liquid tank and the auxiliary cavity and allows liquid and gas to flow from the main liquid tank to the auxiliary cavity. The second vent passage has a flow control device regulating flow through the second vent passage and having a set point at which it allows liquid and gas to flow from the main liquid tank to the auxiliary cavity only when a pressure in the main liquid tank is beyond a threshold. The liquid tank system has an attitude envelope in which the liquid tank system is configured such that, in use, the flow control device blocks flow through the second vent passage when an end of the first vent passage in the main liquid tank is above a liquid level, and the flow control device allows gas and/or fluid flow through the second vent passage when main fluid tank pressure is above the threshold and the end of the first vent passage in the main liquid tank is below the liquid level.

A tank assembly is provided and includes a housing which has a housing volume and which is chargeable with a volume of a first fluid, a bladder disposed within the housing and chargeable with a second fluid such that the bladder has a minimal volume in an uncharged state and a flow system. The flow system includes a portion thereof which is coupled to the bladder and which has a second volume within the housing. The flow system is configured to at least charge the bladder with a volume of the second fluid which is equal to or less than a difference between the housing volume less a sum of the minimal volume and the second volume and the volume of the first fluid.

A tank assembly is provided and includes a housing which has a housing volume and which is chargeable with a volume of a first fluid, a bladder disposed within the housing and chargeable with a second fluid such that the bladder has a minimal volume in an uncharged state and a flow system. The flow system includes a portion thereof which is coupled to the bladder and which has a second volume within the housing. The flow system is configured to at least charge the bladder with a volume of the second fluid which is equal to or less than a difference between the housing volume less a sum of the minimal volume and the second volume and the volume of the first fluid.

A fuel system is provided for an aircraft having a fuel source. The fuel system includes a fuel oxygen reduction unit defining a liquid fuel supply path, a stripping gas supply path, a liquid fuel outlet path, and a stripping gas return path, wherein the stripping gas return path is in airflow communication with the fuel source.