US4187982A Apparatus for increasing the transmission capacity of remote heating grids
Patents citing this work · United States · 1980
Hofener Weg Germany (30) Foreign Application Priority Data Jul. 9, 1976 AT Austria ............................... 95061/76 Jan. 14, 1977 IAT) Austria ................................... 206/77 51) Int. Cl’........................................... G05D 23/00