Flow rate control apparatus, flow rate control method, and program recording medium recording flow rate control program

A flow rate control method using a flow rate control apparatus comprising a first valve arranged in a flow channel, a second valve arranged in a downstream side of the first valve in the flow channel, a fluid resistor arranged between the first valve and the second valve in the flow channel, a first pressure sensor that measures a pressure in a first volume between the first valve and the fluid resistor, and a second pressure sensor that measures a pressure in a second volume between the fluid resistor and the second valve, wherein the flow rate control method comprises

• calculating a resistance flow rate, which is a flow rate of a fluid flowing through the fluid resistor, based on a first pressure measured by the first pressure sensor and a second pressure measured by the second pressure sensor;
• converting the resistance flow rate to a first valve flow rate, which is the flow rate of the fluid passing through the first valve, based on the first pressure;
• converting the resistance flow rate to a second valve flow rate, which is the flow rate of the fluid passing through the second valve, based on the second pressure;
• controlling the first valve to control the deviation between a first set flow rate and the first valve flow rate;
• and
• controlling the second valve to control the deviation between a second set flow rate and the second valve flow rate.

A program recording medium recording a flow rate control program used for a flow rate control apparatus comprising a first valve arranged in a flow channel, a second valve arranged in a downstream side of the first valve in the flow channel, a fluid resistor arranged between the first valve and the second valve in the flow channel, a first pressure sensor that measures a pressure in a first volume between the first valve and the fluid resistor, and a second pressure sensor that measures a pressure in a second volume between the fluid resistor and the second valve, wherein making a computer exhibit functions as

• a resistance flow rate calculator that calculates a resistance flow rate, which is a flow rate of a fluid flowing through the fluid resistor, based on a first pressure measured by the first pressure sensor and a second pressure measured by the second pressure sensor,
• a first valve flow rate converter that converts the resistance flow rate to a first valve flow rate, which is the flow rate of the fluid passing through the first valve, based on the first pressure,
• a second valve flow rate converter that converts the resistance flow rate to a second valve flow rate, which is the flow rate of the fluid passing through the second valve, based on the second pressure,
• a first valve controller that controls the first valve to control the deviation between a first set flow rate and the first valve flow rate, and
• a second valve controller that controls the second valve to control the deviation between a second set flow rate and the second valve flow rate.