System for controlling operation of turbo type fluid machinery

A turbo-type fluid machine operation control system comprising:

• a turbo-type fluid machine driven by a driving machine;
• means for detecting an operating head or operating pressure of said fluid machine;
• means for arithmetically outputting a rotational speed which produces a preset constant torque of said fluid machine to permit use of all of the capacity of said driving machine in corresponding relation to said operating head or operating pressure;
• means for changing a rotational speed of said driving machine in response to said arithmetically outputted rotational speed, so that even when the operating head or operating pressure of said fluid machine changes, a rotational speed of said fluid machine is controlled so as to maintain the preset constant torque, such that, for a high specific speed fluid machine, when the operating head or pressure is below a rated value, the rotational speed increases and pump capacity increases, and when the operating head or pressure is above the rated value, the rotational speed decreases and pump capacity decreases, to avoid overloading the driving machine;
• and
• means for providing an upper limit for a set rotational speed value given to said means for changing a rotational speed of said driving machine to limit the rotational speed of said driving machine and said fluid machine within a predetermined value.