Steam generator with tube aligning orifice

A heat transfer system comprising:

• a plenum configured to provide feedwater to a plurality of heat transfer tubes;
• a tube sheet configured to couple the plurality of heat transfer tubes to the plenum;
• an orifice plate mounted within the plenum and located adjacent to the tube sheet;
• and
• one or more orifice devices supported by the orifice plate and configured for insertion into one or more of the plurality of heat transfer tubes,
• wherein the one or more orifice devices each comprise a cylindrical body having helical shaped threads,
• wherein the insertion of the one or more orifice devices into the one or more of the plurality of heat transfer tubes determines a corresponding pressure drop of the feedwater in the heat transfer system,
• wherein the orifice plate comprises a through-hole having internal threads formed thereon,
• wherein the helical shaped threads of the one or more orifice devices are configured to mate with the internal threads of the through-hole located in the orifice plate, and
• wherein an insertion depth of the one or more orifice devices within the heat transfer tubes is varied by rotating the one or more orifice devices within the through-hole by one or more partial or complete revolutions.