Patent ID: 6773224
Filing Date: 2004-08-10
Classification: F01D,F04D

Abstract:
A control method for plural numbers of compressors, comprising:decreasing down flow rates of all the compressors which are driven under load operating condition, when a load of plural numbers of the compressors goes down; bringing the compressor, which rushes into surge at the earliest, into an unload operating condition; and increasing up the load of the compressors other than that brought into the unload operating condition, thereby enabling an operation depending upon the load, wherein said plural numbers of the compressors are turbo compressors, and said method further comprises the following steps of: obtaining surge limit of at least one of the compressors in advance; and memorizing the surge limit into memory means, wherein the flow rate is decreased down quickly until a point where the flow rate is larger than the surge limit memorized in said memory means by a predetermined amount, when decreasing down the flow rate of the compressor as the load comes down, and thereafter is changed more slowly than a period before, until a time of rushing into surge.