| 摘要 |
PURPOSE:To improve a controlling characteristic for a flow rate of air with respect to a variation of load by a method wherein a proportional band of a first adjusting meter for adjusting a degree of opening of a vane or a damper is varied in response to an occurrence of variation of load and the flow rate of air is controlled prior to a follow-up of a force fan. CONSTITUTION:A second adjuster meter 19 may input an operating output MV1 of a first adjuster meter as a measured value and a proper degree of opening SVb of a vane or damper as a measured value. An operating output MVb in which its difference is controlled and calculated is inputted to an adder 21 through an upper or lower limiter 20 and added to an operating output MV2 of a second function calculating means. The added operating output MV3 is fed to a control device 18 for controlling the number of rotation. A third function calculating means 22 may input an operating output of a manual/automatic operating unit 17, execute a desired function calculation and vary a proportional band 1/Kp of the first adjuster meter in response to the calculation output. Under an action of the third function calculating means 22, the proportional band is made large in response to a variation of MV2, i.e. a variation of MV3 to decrease a gain and to decrease a degree of opening of the vane or damper and then an operation to limit flow rate of air at the vane is realized. |
