An apparatus to control the rate of flow of a stream of pressurized fluid through a conduit. The apparatus comprises a flow measurement device operatively connected to the conduit, a flow control device operatively connected to the conduit, and a controller operatively connected to the flow control device. The flow measurement device generates an output signal proportionate to the rate of flow of fluid therethrough. The flow control device includes an adjustable orifice wherein upon the opening of the orifice a portion of the stream of pressurized fluid is independently released from the conduit by the flow control device. The controller receives the output signal generated by the flow measurement device and causes the adjustable orifice in the flow control device to open or close as necessary to maintain the flow of pressurized fluid as measured by the flow measurement device within pre-determined limits.