liquid is under pressure and is supplied with said cooling liquid from a liquid supply line 17 also depicted is a control valve assembly 15 which operates to control the flow of liquid to the injection nozzle 30 the injection nozzle 30 controls the flow of cooling liquid which is atomized and injected into the liquid coolant line 9 the cooling liquid flow is a function in response to a temperature sensor 19 mounted in the gas or liquid conduit 26 spaced a distance downstream from the injection nozzle 30 the temperature sensor 19 functions to send a temperature measurement signals to a temperature controller 11 which evaluates the temperature against a desired set point and sends a corrective signal to the control valve assembly 15 to either restrict or increase the flow of the cooling liquid preferably the distance between the temperature sensor 19 and the injection nozzle 30 is distance sufficient to allow the steam to come to equilibrium after the liquid has been injected in the stream to ensure a true measurement of the steams thermal energy thus the control valve assembly 15 operates to vary the water flow in the liquid coolant line 9 which in turn modulates the amount of liquid sprayed into the gas or liquid conduit 26 in the present embodiments the control valve assembly 15 is incorporated into the body of the desuperheater as show in fig2 6 continuing with fig2 4 each depicts a cross sectional close up view of an embodiment of the present invention more specifically turning to fig2 a gas or liquid.