Once-through evaporator for a steam generator
OwnerJoseph E. Schroederinventor
Life of this patent
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Abstract
A steam generator has a once-through evaporator which converts liquid water into steam in tubes over which hot gases flow. Each tube contains a metal tape which is twisted into a helical configuration to induce turbulence in the mist produced by the boiling, and the turbulence insures that the mist wets the inside surfaces of the tubes, thus producing good heat transfer and moderate temperatures in the tubes.
Claims18
A once-through evaporator for a steam generator, said evaporator comprising:
- a supply header for receiving liquid water;
- a discharge header spaced from the supply header for receiving steam;
- tubes extending between and connected to the supply and discharge headers, so that water from the supply header may flow toward the discharge header and be converted to steam by heat to which the tubes are subjected;
- and
- tapes in at least some of the tubes for inducing turbulence in a mist that is produced in such tubes as the water converted to steam in such tubes.
In a steam generator including a duct through which hot gases pass, a superheater and an economizer located in the duct, with the superheater being located upstream from the economizer with respect to the flow of the gases, a pump for delivering liquid water to the economizer, an improved once-through evaporator located in the duct between the superheater and the evaporator and being connected to the economizer and to the superheater such that water from the economizer flows into the evaporator which converts it into a mist flow and then into steam that is directed into the superheater where it leaves as superheated steam, said evaporator comprising:
- tubes which lie within the duct so that the hot gases pass over them;
- and
- a twisted tape located within each tube in the region of the mist flow.
For use in a once-through evaporator, the combination comprising:
- a tube having an inlet end and an outlet end;
- and
- a twisted tape located within the tube and having helical edges that lie along the inside surfaces of the tube.
Dependencies are inferred from the claim text.