Patent ID: 7159400

Claim:
A Rankine cycle apparatus constructed into a closed circulation circuit, which comprises: an evaporator for heating and thereby converting a liquid-phase working medium into a gaseous-phase working medium, using heat from a heat source; an expander for converting heat energy of the gaseous-phase working medium, discharged by said evaporator, into mechanical energy; a condenser for cooling and thereby converting the gaseous-phase working medium, discharged by said expander, to the liquid phase; a supply pump for supplying, in a pressurized condition, the liquid-phase working medium, discharged by said condenser, to said evaporator; and a discharge valve device provided between said supply pump and said evaporator in a portion of said closed circulation circuit where the working medium is in a liquid-phase state, wherein said discharge valve device discharges the working medium out of said closed circulation circuit when an interior pressure of said closed circulation circuit is higher than a predetermined limit pressure level that is lower than at least an allowable maximum pressure level of said expander or said evaporator.