A valve mechanism to effect rapid changes of fluid pressure in a controlled fluid pressure system including, for example, airplane deicer boots. The pressures may change from a high vacuum to a few atmospheres, or from any desired low pressure to and from a relatively high pressure. The mechanism includes an inner housing comprising part of the controlled pressure system with opposite ports communicating respectively with high and low pressures, and interconnected closures opening one port while closing another. The body of the valve comprises first and second chambers which embrace respectively, opposite ends of the housing and the corresponding ports and closures. The first chamber is divided into near and far portions separated by a flexible diaphragm providing one of the closures, and is connected to the other, opening one port while closing the other. The outward annular part of the diaphragm is always exposed in the near portion of the chamber to high pressure and exposed in the middle of the same side to the different high and low pressures admitted to the housing. The whole of the other side of the diaphragm is exposed to different pressures in the far portion via a restricted orifice between the near and far portions and/or via a controlled vent to atmosphere. Opening the vent for the far portion drops the pressure therein to open the high pressure port, close the low pressure port and feeds high pressure fluid to the system. Closing the vent raises the pressure in the far portion via the bleed orifice, closes the high pressure port, opens the low pressure port and evacuates the system. The vent may be controlled manually, or in predetermined cycles, or in response to selected conditions as may be desired.
An airfoil deicer and method for deicing an airfoil wherein the deicer has an outer skin having an elevated modulus of elasticity and a means for introducing a small deflection into the outer skin thereby creating substantial chord-wise tension in the outer skin, the deflection being induced in less than 0.250 seconds. In the method of deicing, the deflection is induced periodically and being completed within a time span of about 0.250 seconds to remove accumulations of ice as thin as 0.06 centimeters.
A unique anti-icing management system for a gas turbine engine is disclosed according to which, at all times, only the required amount of heat is applied to inlet surfaces of the engine to prevent the formation of ice. Heated air is bled from the compressor discharge for this purpose and the amount of flow of the heated air is adjusted by a uniquely operated solenoid valve under the direction of an electronic control responsive to any one of a variety of meaningful conditions including, but not necessarily limited to, temperature of an anti-iced surface at the inlet to the engine, rotational speed of the engine, and the presence of an ice producing meteorological condition. The solenoid valve assumes only two operable positions, namely, a fully open position and a fully closed position, and is operated in a pulsed fashion to control flow on a time basis, rather than on a percentage-of-opening basis which is the conventional mode of operation. A switching operation or mechanism within the electronic control, such as a microprocessor, is responsive to any of the aforementioned conditions to cause the solenoid valve to pulsate according to a predetermined pattern which assures a minimally sufficient flow rate of heated air to the regions to be heated.
A de-icer for de-icing those ice accreting surfaces of a skin formed of a material having a substantially elevated modulus, wherein the de-icer is positioned between a support surface and a surface of the skin obverse to the ice accreting surface and inflated to produce a deformation in the skin sufficient to detach and dislodge accumulations of ice on the ice accreting surface but insufficient to exceed an endurance limit for the material from which the skin is formed. The invention finds use in de-icing aircraft surfaces such as wings, tail surfaces, propellers, rotors such as rotating wings, tail rotors and nose cones.
A de-icer for de-icing those ice accreting surfaces of a skin formed of a material having a substantially elevated modulus, wherein the de-icer is positioned between a support surface and a surface of the skin obverse to the ice accreting surface and inflated to produce a deformation in the skin sufficient to detach and dislodge accumulations of ice on the ice accreting surface but insufficient to exceed an endurance limit for the material from which the skin is formed. The invention finds use in de-icing aircraft surfaces such as wings, tail surfaces, propellers, rotors such as rotating wings, tail rotors and nose cones.
