Temperature control apparatus for a monotube boiler

摘要

The temperature of a monotube boiler is controlled by apparatus that regulates the water flow only. Primary water is supplied to the inlet end of the boiler tube in accordance with the heat furnished to the boiler, and secondary water is injected into the boiler tube at a plurality of points spaced along the tube in accordance with the temperature of the steam as determined by a sensor located just upstream of the outlet end of the tube. One of the injection points, termed the feedback point, is located adjacent to and upstream from the temperature sensor. Feedback water injected at the feedback point has an immediate effect on the temperature sensor which is effective to maintain the steam at a substantially constant output temperature during steady state operation over a wide range in the heat furnished to the boiler, and during transient operation from one state to another caused by rapid and large changes in the heat furnished to the boiler.