1. A hydroturbine apparatus comprising a turbine having radially oriented blades disposed in a circular way; inlet and outlet means intersecting said way; an injector for delivering pressurized steam and water at high velocity against said blades to drive said turbine; means for delivering pressurized steam to said injector including a throttle valve; handle means for actuating said throttle valve; a spill valve connected at an inlet side thereof to a point between said injector and said turbine and at an outlet side thereof to a reservoir; means connecting said handle means with said spill valve to actuate said spill valve in response to actuation of said throttle valve, said spill valve being open during a first portion of the opening movement of said throttle valve and closed thereafter whereby water from said injector automatically bypasses said turbine when said throttle valve is opened to direct only a small amount of steam to said injector and is directed to said turbine thereafter and when said throttle valve is fully opened.

2. A hydroturbine apparatus comprising a turbine having radially oriented blades disposed in a circular way; inlet and outlet means intersecting said way; an injector for delivering pressurized steam and water at high velocity against said blades to drive said turbine; means for delivering pressurized steam to said injector including a throttle valve; said throttle valve comprising a cylindrical housing; a sleeve closely interfitting inside said housing; a plurality of apertures in said sleeve spaced in the axial direction; means defining a recess adjacent to the inner surface of said housing connecting all of said apertures; meAns providing inlet and outlet steam passages, said inlet passage extending through said housing and said sleeve at a point axially spaced from said apertures and said outlet passage intersecting said recess; a pair of axially slidable spool members carried coaxially by a piston rod within said sleeve, one of said spools being of a length at least equal to the axial distance covered by said apertures and adapted to progressively cover said apertures to control the steam flow; the other of said spools being spaced axially from said one spool a sufficient distance to cause said inlet passage to be disposed between said spools in any position of said throttle valve whereby steam is trapped between the two spools and exerts equal pressure in both axial directions to prevent said steam from forcing said valve to the open position; handle means for actuating said throttle valve; a spill valve connected at an inlet side thereof to a point between said injector and said turbine and at an outlet side thereof to a reservoir; means connecting said handle means with said spill valve to actuate said spill valve in response to actuation of said throttle valve, said spill valve being open during a first portion of the opening movement of said throttle valve and closed thereafter whereby water from said injector automatically bypasses said turbine when said throttle valve is opened to direct only a small amount of steam to said injector and is directed to said turbine thereafter and when said throttle valve is fully opened.