| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To improve the efficiency of a screw compressor in a low load operation condition. <P>SOLUTION: The screw compressor includes first and second compression chambers (23a, 23b) and is inverter-controlled. A switching mechanism (60, 70) is provided for switching the first compression chamber (23a) between two stages of a resting state in which fluid is kept substantially at a constant pressure and an operating state in which the fluid is compressed and rises in pressure. A control circuit (90) is provided for controlling an inverter frequency. With the control circuit (90), in a condition that the inverter frequency becomes lower than a predetermined threshold frequency when the first and second compression chambers (23a, 23b) are put in the operating state, the first compression chamber (23a) is brought into the resting state and the inverter frequency is increased. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
