Abstract An improved startup system for a vapor generator of the oncethrough type. The system includes a startup bypass line which leads directly to the tube side of a shell and tube feedwater heater for the generator feedwater circuit, from certain heating passes of the generator main flow circuit; a branch line which leads from the bypass line to the shell side of the heater; and a return line which returns the flow from the heater shell side back to the generator main flow circuit downstream of the bypass line. A pressure reducing valve in the branch line reduces the pressure of the fluid flowing therein lowering its temperature for heat exchange with fluid on the tube side of the heater. The feedwater circuit of the generator includes a bypass around the heater, the generator further having shutoff valves in both the startup system and feedwater circuit for isolating the heater from one or the other of the main flow or feedwater circuits depending upon use of the heater.
Inventors
👤 William D Stevens
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-30 12:38
CPC Classifications
F; F22; F22B; F22B35/00; F22B35/06; F22B35/14
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
179 words
In a startup system for a once-through vapor generator of the type including a main flow path having heating surfaces therein, a feedwater circuit for said main flow path, said circuit including a plurality of feedwater heaters, at least one of which is of the tube and shell type, the improvement comprising a bypass line connected between said main flow path and the tube side of said tube and shell feedwater heater; a branch conduit in flow communication with said main flow path leading to the shell side of said tube and shell feedwater heater; a pressure reducing means in said branch line; a return line leading from said shell side back to said main flow path downstream of said bypass line; a bypass conduit in said feedwater circuit around said tube and shell heater; and means to isolate said tube and shell heater from either the main flow path or the flow in the feedwater circuit, the tube and shell heater thereby being employed either as a feedwater heater or a heat exchanger for the generator bypass flow.
Claim 2
Dependent Claim
179 words
In a startup system for a once-through vapor generator of the type including a main flow path having heating surfaces therein, a feedwater circuit for said main flow path, said circuit including a plurality of feedwater heaters, at least one of which is of the tube and shell type, the improvement comprising a bypass line connected between said main flow path and the tube side of said tube and shell feedwater heater; a branch conduit in flow communication with said main flow path leading to the shell side of said tube and shell feedwater heater; a pressure reducing means in said branch line; a return line leading from said shell side back to said main flow path downstream of said bypass line; a bypass conduit in said feedwater circuit around said tube and shell heater; and means to isolate said tube and shell heater from either the main flow path or the flow in the feedwater circuit, the tube and shell heater thereby being employed either as a feedwater heater or a heat exchanger for the generator bypass flow.
Claim 3
Dependent Claim
51 words
The system of claim 1 including shutoff valves to isolate the tube and shell heater from the feedwater circuit, further including a shutoff valve in the bypass conduit and shutoff valves between said tube and shell heater and the main flow path to isolate the heater from the main flow path.
Claim 4
Dependent Claim
24 words
The system of claim 1 wherein said pressure-reducing means includes a controller responsive to pressure in the shell of the tube and shell heater.
Claim 5
Dependent Claim
62 words
The system of claim 1 including at least two heaters, said shell and tube heater being downstream of the other heater in the feedwater circuit, further including a conduit connected to receive the exhaust flow from the tube side of the shell and tube heater and to transmit the flow to said other heater for heat exchange with the feedwater flow therein.
Claim 6
Dependent Claim
11 words
The system of claim 4 including pressure-reducing means in said conduit.