Nikola Tesla U.S. Patent 1,061,206 - Turbine Patent Wrapper Page 10

874 Sub. per C 11 9074 effective speed. For this reason, the performance of such machines augments at an exceedingly high rate with the increase of their size and speed of revolution. The dimensions of the device as a whole, and the spacing of the disks in any given machine will be determined by the conditions and requirements of special cases. It may be stated that the intervening distance should be the greater, the larger the diameter of the disks, the longer the spiral path of the fluid and the greater its viscosity. In general, the spacing should be such that the entire mass of the fluid, before leaving the runner, is accelerated to a nearly uniform velocity, not much below that of the periphery of the disks under normal working conditions, and almost equal to it when the outlet is closed and the particles move in concentric circles. Considering now the converse of the above described operation and tion and assuming that water or air under pressure be admitted to the opening 11, the runner, as has been stated above, is set in rotation in the direction of the dotted arrow, the fluid travelling in a spiral path and with continuously diminishing velocity until it reaches the orifices 6 and 10 through which it is discharged. If the runner be allowed to turn freely, in nearly fricticnless bearings, its rim will attain a speed adjacent closely approximating the maximum of that of the fluid in the Home 21 volute chanel and the spiral path of the particles will be comparatively long, consisting of many almost circular turns. If load is put on and the runner slowed down, the motion of the fluid is retarded, the turns are reduced, and the path is shortened.