Flow control for once-through boiler having integral separators
AssigneeWestinghouse Electric Corp.
InventorMorton H. Binstock
Life of this patent
Estimating the term…
Abstract
A once-through boiler is provided with integral separators with which drain valves are associated. Boiler inlet and outlet flows are balanced throughout startup first by drain valve control in response to separator level and then by drain valve control in response to throttle pressure.
Claims10
A startup system for a once-through boiler having a boiler feed pump for controllably driving water as a working fluid through the boiler tubes where heat is added to the working fluid under burner control, said system comprising separator means disposed in the main boiler flow path, means for detecting separator level, drain valve means for varying a drain flow from the separator means to balance boiler inflow and outflow during startup, first means for controlling said drain valve means for boiler flow balance during startup in response to a separator water level signal from said detecting means over a first working fluid pressure range up to a pressure below supercriticality, means for displacing said first control means from controlling effect at pressure above the first range and at a pressure below a pressure value at which the level signal becomes invalid, and second means for controlling said drain valve means for boiler flow balance during startup in response to a signal representative of at least one predetermined boiler operating parameter other than separator level at pressures above the first pressure range.
A startup control for a once-through boiler having a boiler feed pump for controllably driving water as a working fluid through the boiler where heat is added to the working fluid under burner control and further having separator means in the main boiler flow path with drain valve means associated therewith, said control comprising means for detecting separator level, and first means for controlling said drain valve means for boiler flow balance during startup in response to a separator water level signal from said detecting means over a first working fluid pressure range up to a pressure below supercriticality, means for displacing said first control means from controlling effect at pressures above the first range and at at pressure below a pressure value at which the level signal becomes invalid, and second means for controlling said drain valve means for boiler flow balance during startup in response to a signal representative of at least one predetermined boiler operating parameter other than separator level at pressures above the first pressure range.
Dependencies are inferred from the claim text.