Flow rate control device

A flow rate control device comprising:

• a flow rate meter that measures a flow rate of a fluid flowing through a flow path;
• a flow rate regulating valve that regulates the flow rate of the fluid flowing through the flow path;
• and
• a control part that controls an opening degree of the flow rate regulating valve based on a measurement result of the flow rate meter,
• wherein the flow rate control device includes:
• a low flow rate rapid valve opening function that accelerates an outflow of the fluid by forcibly opening the opening degree of the flow rate regulating valve from fully closed degree to a designated opening degree when the opening degree of the flow regulating valve is fully closed and a flow rate control is started;
• and
• an overshoot suppressing function that is used for suppressing the overshoot by, immediately after the low flow rate rapid valve opening function starts to work, standing by in a state holding the opening degree of the flow rate regulating valve being forcibly opened to the designated opening degree till whichever comes first between a lapse of a duration of a preset standby time and a preset flow rate threshold being reached,
• wherein the preset flow rate threshold is determined to be reached when a specified flow rate variation amount or less and a specified number of sampling times or more are detected, or when a set flow rate value or more is continuously detected for a plurality of times.