| 摘要 |
PURPOSE:To enable stand-by operation in a completely closed cycle without generating the breakdown of a device, the contraflow of supply gas to a main pipe, or the like. CONSTITUTION:A check valve 3 is provided in the suction passage of a compressor body 1. A by-pass passage 7 with a pressure regulating valve 6 interposed at its intermediate part is branched from the discharge passage 4 of the compressor body 1, on the upstream side of a switching valve 5 provided at this discharge passage 4, and joins the check valve downstream side part of the suction passage 2. A pressure controller 11 is provided to detect discharge pressure in the discharge passage 4 so as to control the valve opening of the pressure regulating valve 6 to be small at the time of the detected pressure being less than the set value. In the pressure control method of a compressor of such structure, plural values are determined as the above-mentioned set value, and the lower limit value of the valve opening in the case of the above-mentioned detected pressure being less than the above-mentioned set value is determined by set value by set value, and to be smaller as the set value is smaller. |
