| 摘要 |
PURPOSE:To keep the degree of superheat at the inlet side of an expander constant by providing a circulating quantity control valve on a bypass path communicating between the inlet side and outlet side of a pump and operating the control valve by means of an electric signal based on the deviation between the degree of superheat at the inlet side of the expander and the preset degree of superheat. CONSTITUTION:The inlet side and outlet side of a pump 7 are communicated to each other by a bypass path 8, a circulating quantity control valve 9 is provided on the bypass path 8, and the control valve 9 is operated by the deviation 15 between an electric signal from an inlet superheat degree calculator 13 of an expander 3 and an electric signal from a target superheat degree setter 14. Thereby, when the degree of superheat 13a of the inlet superheat degree calculator 13 is larger than the target superheat degree 14a, the deviation 15 becomes a negative valve and the orifice of the circulating quantity control valve 9 is left closed. On the contrary, when the inlet superheat degree 13a is smaller than the preset superheat degree 14a, the deviation 15 becomes a positive value and the orifice of the circulating quantity control valve 9 is opened. Accordingly, the degree of superheat at the inlet side of the expander is kept constant. |
