GB1050088A - - Google Patents

Abstract

1,050,088. Variable speed control. L. BENING. Feb. 17, 1964, No. 6601/64. Heading F2D. [Also in Division F1] A wind motor comprises a wind wheel driving variable hydraulic pumping means delivering fluid through a calibrating valve to a variable hydraulic motor, and means controlling the volume output of the pump and the calibrating valve so that the volume of fluid delivered is proportional to the third power of the wind velocity, the calibrating valve maintaining a constant delivery pressure to the variable hydraulic motor. The wind wheel 2 drives an infinitely variable hydraulic pump 14 through gearing 12. The output of the pump 14 flows through an adjustable calibrating valve 23 to a variable hydraulic motor 29 driving a load through a shaft 30. The pitch of the wheel vanes 1 is controlled by a servo-piston 10 and the output of the pump 14 and the setting of calibrating valve 23 by a servopiston 20 and cam 15. The torque of the hydraulic motor 29 is controlled by a servopiston 59. Pump 14 is set so as to commence rotation at a wind speed of 3 metres/sec. and calibrating valve 23 correspondingly set by cam 15. The starting position of adjustable vanes 1 is determined by springs 9 and 11 acting on piston 10. As the wheel 2 begins to rotate the pressure in the hydraulic system increases and forces piston 10 to the left, moving the vanes 1 into their optimum pitch and causing the wheel 2 to. rotate faster. When the hydraulic pressure reaches working level, piston 61 is forced downwardly to close off duct 64 and motor control piston 59 is held at its lowest torque position by spring 58. If the load torque on shaft 30 is greater than the torque of the hydraulic motor 29, the motor remains stationary, pressure in the system increases and piston 61 moves downwardly to place ducts 53, 64 in communication. Piston 59 thus moves upwardly and sets motor 29 for a higher torque until the load torque is overcome at which point the motor starts to rotate. Piston 61 returns to its normal position closing off duct 64 and fixing the setting of the motor. Further resetting of the motor torque occurs with subsequent change in the load torque. When the flow output of pump 14 exceeds the setting of calibrating valve 23 owing to an increase in the wind velocity and rotational speed of the wheel 2, pressure in ducts 40, 48 increases causing piston 24 to move downwardly and place ducts 48, 49 in communication. Whereupon piston 20 moves downwardly to increase the pump output in proportion to the cube of the wind velocity. The setting of calibrating valve 23 is simultaneously varied by cam 15 so as to maintain a constant delivery pressure to the hydraulic motor 29. The final setting of pump 14 and calibrating valve 23 is reached at a wind velocity of 7 metres/sec. Above 7 metres/see. the output of pump 14 increases linearly owing to the increased rotational speed of the wheel 2. The pressure in ducts 40, 46 thus increases and differential pressure valve 31 opens to supply hydraulic fluid through flow limiting valve 34. Metering orifice 35 of valve 34 is designed so that above a wind velocity of 12 metres/sec. a pressure build-up in ducts 46, 48 causes piston 10 to move to the right to reset the pitch of the vanes 1 such that the rotational speed of the wheel 2 does not increase further. A cut-off valve 27 is provided to bring the installation to a standstill. Operation of the cut-off 27 causes the pump 14 to be set for maximum torque and the vane pitch setting piston 10 to move to the right thus braking the wheel 2. The wind wheel 2 may be turned into the wind by a vane or turbine. The variable hydraulic pump or motor may be variable by association with a variable gear, rather than in itself.