A sub-cooler for a sub-cooling cryogenic refueling system is disclosed herein. The sub-cooler includes a first valve to separate flowing cryogenic fuel into a primary flowline and an auxiliary flowline, a second valve to reduce the saturated pressure and temperature of the cryogenic fuel in the auxiliary flowline, a cryogenic heat exchanger to transfer heat from the primary flowline to the auxiliary flowline, a temperature sensor to measure the temperature of the sub-cooled cryogenic fuel in the primary flowline, and a sub-cooler controller to control the effective areas of the primary flowline inlet and the auxiliary flowline inlet at the first valve.

A hydrogen fuel system for an aircraft is configured to provide hydrogen fuel to the engines for propulsion. The fuel system also may provide hydrogen fuel to a fuel cell arrangement to generate electricity for use on the aircraft. The fuel cell arrangement may be selectively coupled to the feed lines for the engines. A ventilation system regulates the pressure within the one or more fuel tanks and the feed lines. The ventilation system can vent hydrogen vapor to atmosphere or can transfer hydrogen vapor between the fuel tanks and the fuel cell arrangement. A jet pump and accumulator may pull vapor from the feed lines as needed.

A hydrogen fuel system for an aircraft is configured to provide hydrogen fuel to the engines for propulsion. The fuel system also may provide hydrogen fuel to a fuel cell arrangement to generate electricity for use on the aircraft. The fuel cell arrangement may be selectively coupled to the feed lines for the engines. A ventilation system regulates the pressure within the one or more fuel tanks and the feed lines. The ventilation system can vent hydrogen vapor to atmosphere or can transfer hydrogen vapor between the fuel tanks and the fuel cell arrangement. A jet pump and accumulator may pull vapor from the feed lines as needed.

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 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 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 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 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 system for dispersing a catalyst in a fuel includes a first reservoir containing the fuel, and a second reservoir including an agitator and containing a quantity of the catalyst suspended in the fuel. The system also includes a first conduit extending from the first reservoir, a second conduit extending from the second reservoir, and a mixing nozzle connected to the first conduit and the second conduit. The mixing nozzle includes a first meter positioned within the first conduit, a second meter positioned within the second conduit, a valve positioned upstream from the second meter within the second conduit, a junction in flow communication with the first conduit and the second conduit, a mixer downstream from the junction, a sensor positioned between the mixer and an outlet; and a controller connected to the valve and the first and second meters, the controller receiving feedback from the sensor.

A method of recovering fuel vapour from a fuel tank of an aircraft, is disclosed. The aircraft includes a fuel tank; a wing with an upper surface and a lower surface; and an opening in the lower surface of the wing. The method includes coupling an inlet of a vapour recovery system to the opening; capturing fuel vapour from the fuel tank which flows out of the opening with the inlet of the vapour recovery system; and collecting the captured fuel vapour in a vapour storage tank of the vapour recovery system.