APARATO MEJORADO PARA CONTROLAR EL FLUJO DE UN FLUIDO

摘要

A plurality of spray nozzles are utilized to introduce a fluid into a vessel. Control valves are associated with each one of the plurality of spray nozzles. The control valves are either fully closed or fully open. The actual value of a process variable is compared to the desired value of the process variable to generate a difference signal. Control signals are generated in response to the difference signal. Different combinations of the control valves are opened in response to the control signals so as to provide a fluid flow rate which will maintain the actual value of the process variable substantially equal to the desired value. The on-off nature of the control valves provides a substantially maximum pressure drop across the spray nozzles when fluid is flowing through the spray nozzles.