Improvements in or relating to fuel tanks

• Main Author: SMEDLEY FREDERICK EDWARD SAMUEL
• Format: Patent
• Language: English
• Published: 23.05.1951
• Subjects: AIRCRAFT; ARRANGEMENTS OR MOUNTING OF POWER PLANTS OR PROPULSIONTRANSMISSIONS IN AIRCRAFT; AVIATION; COSMONAUTICS; EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLYING SUITS; PARACHUTES; PERFORMING OPERATIONS; TRANSPORTING

653,667. Venting tanks. ROLLS-ROYCE, Ltd. June 10 1948, No. 15716. [Class 21] [Also in Group XXIX] To prevent the fuel volatilizing at high rates of climb in an aircraft fuel installation the tank is vented through a valve which is moved or loaded in the sense of closure by means responsive to the rate of change of ambient atmospheric pressure, so that, at least when a predetermined rate of decrease in ambient pressure occurs, the valve is closed and the fuel tank becomes pressurized relative to the ambient atmosphere to an extent at least in part dependent on said rate of decrease in ambient atmospheric pressure. In one form. an expansible capsule 7 carries at one end a disc valve 5, which is arranged between the vent line 2 and interior of the tank 1, the interior of the capsule con-. necting via an orifice 8 with an air chamber 9 vented to atmosphere through a restricted bleed orifice 10. In level flight the pressure in the vent line is the same as that within the air chamber 9, and therefore the capsule 7 and the valve 5 is held open. At high rates of climb the bleed orifice 10 ensures that the rate of fall of pressure within the air chamber is less than the rate of fall of atmospheric pressure within the vent line 2 so that the capsule expands, closes the valve 5 and pressurizes the tank. On assuming level flight, the air in the chamber 9 leaks out through the bleed orifice 10, the valve 5 opens and the tank decompresses. A spring-loaded relief valve 13 prevents pressure in the tank reaching a dangerous value in a sustained climb and a valve 16 may be fitted within the relief valve 13 to prevent an excessive negative pressure developing within the tank. In a modification a spring is interposed between the capsule 7 and valve 5 so that the tank is pressurized during level flight, the degree of pressurization being increased during a climb by the capsule. If the device is used in conjunction with nitrogen purged tanks, the restricted orifice 10 is connected to the fuel-tank vent-line upstream of the nitrogen vent outlet valve.