| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a material gas concentration control system that can improve control response in decreasing or increasing a concentration even if a pressure in a storage chamber is difficult to increase or decrease, for example, because the volume of the storage chamber is large relative to the flow rate of a carrier gas. <P>SOLUTION: An inlet pipe 20 for leading a carrier gas into a storage chamber 10 is provided with a flow controller 50, and an outlet pipe 30 for leading out a mixture gas comprising a material gas and the carrier gas is provided with a concentration controller 40. The flow controller 50 includes a second valve control section 54 for regulating the travel of a second regulation valve 52 such that a measured flow rate measured by a flowmeter 51 becomes a predetermined reference value, in a first state in which the absolute value of a deviation of a measured concentration index value measured by a measuring unit 41 from a set point is a predetermined value or less, and regulating the travel of the second regulation valve 52 such that the measured flow rate exceeds the reference value, in a second state in which the absolute value of the deviation is greater than the predetermined value and the measured concentration index value is greater than the set point. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
