摘要 |
<p>A valve is one of a plurality of similar valves set out in the form of a matrix to constitute a portion of the fuel control system of a gas turbine engine. The valve comprises a piezo-electric crystal and is deformable by the application of a potential difference thereto from a first, non-deformed condition in which the crystal blocks the orifice to second deformed condition in which the orifice is unblocked. At least some of the valves are normally redundant but are caused to become operable in the event of the failure of any of the other operable valves.</p> |