Pressurized medium temperature hot water system

Claim 1

A GAS PRESSURIZED COMPRESSION ARRANGEMENT FOR A MEDIUM TEMPERATURE TYPE CLOSED HOT LIQUID HEATING SYSTEM HAVING A SOURCE OF HOT LIQUID, RADIATION GEAR, AND MEANS FOR CIRCULATING HOT LIQUID BETWEEN SAID SOURCE AND SAID RADIATION AND INCLUDING MAIN SUPPLY AND RETURN LINES AND A PUMP AND GAS SEPARATION TANK CONNECTED IN SERIES IN ONE OF SAID LINES, SAID SEPARATION TANK HAVING A VENT FOR RELEASING GAS SEPARATING FROM LIQUID IN SAID TANK, SAID ARRANGEMENT COMPRISING A COMPRESSION TANK HAVING A LOW LEVEL CONTROL AND A HIGH LEVEL CONTROL, MEANS CONNECTED TO SUPPLY GAS UNDER PRESSURE TO SAID COMPRESSION TANK FOR MAINTAINING A MINIMUM PRESSURE THEREIN OF A VALUE TO PREVENT CAVITATION IN SAID PUMP AT ALL OPERATING CONDITIONS OF SAID SYSTEM, A BALANCE LINE CONNECTING THE LIQUID PHASE IN SAID COMPRESSION TANK TO ONE OF SAID LINES TO PROVIDE FOR LIQUID FLOW FROM SAID SYSTEM TO SAID COMPRESSION TANK DURING EXPANSION OF LIQUID IN SAID SYSTEM AND TO PROVIDE FOR LIQUID FLOW FROM SAID COMPRESSION TANK TO SAID SYSTEMDURING CONTRACTION OF LIQUID IN SAID SYSTEM, A GAS RETURN LINE CONNECTED FROM SAID VENT TO COMMUNICATE WITH THE UPPER END OF SAID COMPRESSION TANK TO RETURN GAS TO SAID COMPRESSION TANK, A FILL TANK, A NORMALLY CLOSED TRANSFER LINE CONNECTED FOR TRANSFERRING LIQUID FROM SAID COMPRESSION TANK TO SAID FILL TANK, MEANS RESPONSIVE TO OPERATION OF SAID HIGH LEVEL CONTROL FOR UNBLOCKING SAID TRANSFER LINE UNTIL THE LEVEL OF LIQUID IN SAID COMPRESSION TANK IS REDUCED A PREDETERMINED AMOUNT BY FLOW OF LIQUID FROM SAID COMPRESSION TANK TO SAID FILL TANK, MEANS INCLUDING A NORMALLY CLOSED RETURN LINE CONNECTED FOR TRANSFERRING LIQUID FROM SAID FILL TANK TO SAID COMPRESSION TANK, AND MEANS RESPONSIVE TO SAID LOW LEVEL CONTROL FOR UNBLOCKING SAID RETURN LINE UNTIL THE LEVEL OF LIQUID IN SAID COMPRESSION TANK IS RAISED A PREDETERMINED AMOUNT BY FLOW OF LIQUID FROM SAID FILL TANK TO SAID COMPRESSION TANK.