The object of the invention herewith illustrated is to provide for steam engine governors and steam pressure regulators a simple and reliable balance valve for controlling the flow of steam. In one side of the cylindrical casing is a branch pipe communicating with an annular recess within the casing. Within the casing is a loosely fitted piston, resting upon a spiral spring supported upon a fillet formed in the lower end of the casing. The piston ro<fpasses through a gland in the cap and enters small steam cylinder, where it' iS attached to a piston fitting steam tight. In the upper end of this cylinder is inserted a steam supply pipe for furnishing steam from the pipe which is supplied with steam through the valve casing. In the lower end of this cylinder is a small aperture for maintaining atmospheric pressure under the piston. Steam may enter the casing through the bottom opening or through the branch pipe, and in its passage must necessarily pass between the different convolutions of the spring. When the upper piston is forced downward by increased pressure, the spring is contracted and the area of the passage through the valve is diminished until the pressure in the supply pipe has reached the prescribed limit. Should this pressure become too greatly reduced, the spring will expand, and by increasing the area of the passage, allow more steam to flow through. When this device is used in connection with an automatic engine governor, the spring is operated directly by the valve-operating spindle of the governor. This invention has been patented by Mr. James P. Walters, of Rosedale, Ind.