US PATENT SUBCLASS 165 / DIG 441
.~.~.~ Helical

Current as of: June, 1999
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165 /   HD   HEAT EXCHANGE

DIG 355  DD  HAVING SEPARATE FLOW PASSAGE FOR TWO DISTINCT FLUIDS {7}
DIG 400  DD  .~ Shell enclosed conduit assembly {4}
DIG 440  DD  .~.~ Coiled conduit assemblies {1}
DIG 441.~.~.~ Helical