Dual end plate subcooling zone for a feedwater heater

Abstract

Steam power plants utilize high pressure and low pressure feedwater heaters to increase overall system efficiency. Both types of feedwater heaters generally include a subcooling zone that is separate from a condensing zone. The viability of the separation of the zones is critical to the efficiency of the overall system, specifically with regard to the inefficiencies inherent in the leakage of steam from the condensing zone into the subcooling zone. An improvement in the viability of that zone separation for such feedwater heaters is taught by the use of dual end plates for the subcooling zone to create a triple layer of separation between the condensing and subcooling zones to prevent unwanted and inefficient steam leakage.

What is claimed is: 
     
         1 . A dual end plate apparatus for use in a feedwater heater comprising:
 an outer end plate separating a condensing zone from a water seal having a plurality of tubes passing through holes in said end plate; and   an inner end plate separating a subcooling zone from a water seal having a plurality of tubes passing through holes in said end plate, whereby said water seal separates said inner end plate and outer end plate.   
     
     
         2 . The apparatus of  claim 1  further comprising:
 a semicircular plate welded to said inner end plate and to said outer end plate; and 
 a horizontal plate welded to said inner end plate and to said outer end plate, whereby said semicircular plate and said horizontal plate form an enclosure between said inner end plate and said outer end plate. 
 
     
     
         3 . The apparatus of  claim 2  further comprising holes in said horizontal plate in order to permit condensate to flow into and collect in said enclosure. 
     
     
         4 . The apparatus of  claim 2  further comprising a drain at the bottom of said semicircular plate in order to drain condensate collected in said enclosure. 
     
     
         5 . A dual end plate apparatus for use in a low-pressure feedwater heater comprising:
 an outer end plate separating a condensing zone from a water seal having a plurality of tubes passing through holes in said end plate; and   an inner end plate separating a subcooling zone from a water seal having a plurality of tubes passing through holes in said end plate, whereby said water seal separates said inner end plate and outer end plate.   
     
     
         6 . The apparatus of  claim 5  further comprising:
 a semicircular plate welded to said inner end plate and to said outer end plate; and 
 a horizontal plate welded to said inner end plate and to said outer end plate, whereby said semicircular plate and said horizontal plate form an enclosure between said inner end plate and said outer end plate. 
 
     
     
         7 . The apparatus of  claim 6  further comprising holes in said horizontal plate in order to permit condensate to flow into and collect in said enclosure. 
     
     
         8 . The apparatus of  claim 6  further comprising a drain at the bottom of said semicircular plate in order to drain condensate collected in said enclosure. 
     
     
         9 . A dual end plate apparatus for use in a high-pressure feedwater heater comprising:
 an outer end plate separating a condensing zone from a water seal having a plurality of tubes passing through holes in said end plate; and   an inner end plate separating a subcooling zone from a water seal having a plurality of tubes passing through holes in said end plate, whereby said water seal separates said inner end plate and outer end plate.   
     
     
         10 . The apparatus of  claim 9  further comprising:
 a semicircular plate welded to said inner end plate and to said outer end plate; and 
 a horizontal plate welded to said inner end plate and to said outer end plate, whereby said semicircular plate and said horizontal plate form an enclosure between said inner end plate and said outer end plate. 
 
     
     
         11 . The apparatus of  claim 10  further comprising holes in said horizontal plate in order to permit condensate to flow into and collect in said enclosure. 
     
     
         12 . The apparatus of  claim 10  further comprising a drain at the bottom of said semicircular plate in order to drain condensate collected in said enclosure. 
     
     
         13 . A multiple end plate apparatus for use in a feedwater heater comprising:
 an outer end plate separating a condensing zone from a water seal having a plurality of tubes passing through holes in said outer end plate;   at least one additional plate forming a boundary of a water seal having a plurality of tubes passing through holes in said plate; and   an inner end plate separating a subcooling zone from a water seal having a plurality of tubes passing through holes in said inner end plate; whereby said multiple plates form a plurality of water seals separating said condensing zone from said subcooling zone.   
     
     
         14 . The apparatus of  claim 13  further comprising:
 a semicircular plate welded to said inner end plate, to each of said additional plates, and to said outer end plate; and 
 a horizontal plate welded to said inner end plate, to each of said additional plates, and to said outer end plate, whereby said semicircular plate and said horizontal plate form an enclosure between said inner end plate and said outer end plate. 
 
     
     
         15 . The apparatus of  claim 14  further comprising holes in said horizontal plate in order to permit condensate to flow into and collect in said enclosure. 
     
     
         16 . The apparatus of  claim 14  further comprising a drain at the bottom of said semicircular plate in order to drain condensate collected in said enclosure.