GB720591A - Improvements in or relating to wind-motors - Google Patents

Abstract

720,591. Wind-motors. BUREAU D'ETUDES SCIENTIFIQUES ET TECHNIQUES. Feb. 13, 1951 [Feb. 13, 1950], No. 3446/51. Class 110 (3). [Also in Group XXIX] In a wind-motor, the blades are provided on their leading edges with spoilers, each in the form of a number of teeth, each tooth having a head which is rounded or is in the form of, for example, a truncated cone, the teeth preferably being connected together inside the blades. The spoilers are normally flush with the surface of the blade but can be protruded to cause aerodynamic stalling and thus prevent overspeeding. A spoiler comprises three teeth 91, Fig. 1, which project through holes 97 in the leading edge 95 of a wind-motor blade 96 and are carried by bars 93, 94, the latter being pivoted on parallel arms 110, 111. Arm 110 is connected by links 122, 124 to a cylinder 116 which is slidable on a hollow piston 117 pivoted at 120 to the blade 96. Compressed air is admitted at 128 and passes through the hollow piston 117 and a nozzle 129 into the cylinder 116. Counterweights 114, 115 ensure that the teeth are retracted when the wind-motor is stationary. The frusto-conical heads 92 of the teeth are then flush with the leading edge 95. The compressed air for operation of the spoilers can be supplied by a swashplate pump 17, Fig. 2, which discharges through valves 19, 19<SP>1</SP> into a succession of cylinders 14, 15, 16 which are interconnected by valves 20, 21. A valve 22 connects the cylinder 16 to atmosphere. The cylinders are thus changed to successively lower pressures. As the wind-motor speed increases, a centrifugal governor 31 moves a sliding valve 27 so that the air outlet pipes 36 are successively connected to the cylinders 14, 15 and 16 respectively. Ball detents 41 hold the valve 27 in the successive positions with the appropriate ports in alignment. The shaft 18 is rotated in the opposite direction to the windmotor hub 13. The spoilers are so adjusted that one set of spoilers is operated when the valve 27 is in its intermediate position and a further set is operated when the valve is in the position corresponding to the highest speed. The cylinders may be arranged concentrically around a central cylinder, and the valves 27 may be of the rotary type. Instead of being frusto-conical, the heads of the spoiler teeth may be rounded or spherical.