Patent GB-217628-A (GB)
Title: Regulating system for hydraulic turbines
IPC: F03B15/12
Filed: 1923-03-06
Abstract: 217,628. Moody, L. F. March 6, 1923. Regulating.-In hydraulic power systems comprising a number of turbines driving electric alternators running in parallel, a regulating system is provided whereby a limited number of governors is adapted to exercise a limited control over all the turbines, distributing the load among the turbines and at the same time securing isochronous governing. In a plant comprising two or more turbine units T<1>, T<2> driving alternators E, the governing mechanism of the unit T<1> regulates all the units. The speed governor 15 controlling the gates G moves vertically the central pin of a floating lever 16, the left-hand end of which is held stationary during quick load changes by the rod 17 and dashpot 18. The right-hand end moves a rod 19 actuating the. pilot valve of a relay 20 operating a rod 21, which by means of a bell-crank 22 moves a rod 30 interconnecting the units of the regulating system. In any unit, say T<2>, the rod 30 actuates the main control valve 34<1> of the operating restoring device 24 actuated by the rod 25 of cylinder 27<1> for the gates G, through a bell crank 22<1>, link 21<1> and lever 26<1>. By means of a restoring device 24 actuated by the rod 25 of the piston controlling the gates G, the left-hand end of the floating lever 26<1> is moved with the gates and the valve 34<1> is restored to its neutral or mid-position. A secondary compensation of slow action is secured by means of the dash-pot 18 and the floating lever 28, which under the action of a spring 29 tends to move slowly the rod 17 and readjust the rods 19, 21, giving the gates of all the units a simultaneous additional motion in the same direction. To secure accurate distribution of the load among the units, a hand-wheel 31 on each unit adjusts the point of connection between the floating lever 26<1> and the primary restoring mechanism. Also, each unit may be provided with a hand-controlled valve 32' for the fluid-pressure supply to operating cylinders 27, 27'. More than one governor may be installed, each of which may take over the whole control, and any governor may be, removed by disconnecting the upper portion of rod 21. Fig. 1<a> shows a method of connecting the rods 21 by rods 41 to a differential equalizer 42 so that the control rod 30<1> is actuated and controlled by the average gate position of the units T', T<2>. To adapt certain units for relatively slow regulation, the piping and water passages of these units may be made smaller. In a modication, a limited number of units have quick wicket-gate regulation, the remaining units having slow plunger-gate control. The secondary units T<2> may be each provided with a special operating stand h, Fig. 6, and connecting mechanism moving the gates slowly compared with the gates of the first unit. The stand h contains a valve 63 controlling the fluid-pressure supply to the relay actuating the turbine gates. The valve stem 62 is screw-threaded in the valve, so that by rotating the hand-wheel 70 the valve may be adjusted vertically so as to shut down the gates wholly or partly. An electric motor 72 and suitable gear are provided for remote control of the valve 63. A speed-limiting device adapted to cause the valve 63 to shut-down the gates on a predetermined rise of speed comprises a piston arranged on an extension of the spindle 62 and subjected to fluid-pressure when a centrifugal governor head engages a valve-rod. This piston and its cylinder constitute also a dash-pot controlling the rate of gate motion, an adjustable by-pass valve in the piston being provided to vary the rate.