Gas supply device capable of measuring flow rate, flowmeter, and flow rate measuring method

Abstract

According to the present invention, a gas supply device capable of measuring a flow rate is provided with: a flow rate controller which controls the flow rate of a passing gas; a first shutoff valve provided downstream of the flow rate controller; a second shutoff valve provided in a first flow passage which communicates with the downstream side of the first shutoff valve; a second flow passage which branches from the first flow passage; a third shutoff valve provided in the second flow passage; a pressure detector which detects the pressure in a flow passage surrounded by the first, second and third shutoff valves; a temperature detector which detects the temperature in the flow passage surrounded by the first, second and third shutoff valves; a tank for volume measurement which is connected downstream of the third shutoff valve and has a known volume; and an arithmetic and control device which finds the volume of the flow passage surrounded by the first, second and third shutoff valves by applying Boyle's law with the third shutoff valve in an open state and a closed state, and also calculates the flow rate of the flow rate controller using the flow passage volume and detected values from the pressure detector and the temperature detector.

Description

technical field [0001] The present invention relates to a gas supply device capable of measuring a flow rate, a flow meter, and a flow measurement method. Background technique [0002] Conventionally, in a semiconductor manufacturing process or the like, a gas supply device provided with a flow controller, a valve, or the like has been used in order to supply processing gas or the like at a predetermined flow rate. This kind of flow controller needs to measure the flow and check the control accuracy because of the demand for high-precision flow control. As a method of measuring the flow rate, the ROR (rate of rise) method (also called the buildup method) for measuring the flow rate based on the pressure rise rate is widely known (Patent Documents 1, 2, etc.). [0003] The ROR method is to make the gas whose flow rate is controlled by a flow controller flow in a predetermined volume (V) existing in the flow path, and use Q=( ΔP / Δt) × V / RT relationship (R is the gas constant...

AI Technical Summary

Problems solved by technology

[0009] However, in the conventional ROR method, the volume (V) is measured with a flow controller, and the measured volume (V) may contain errors because the flow rate controlled by the flow controller used for the measurement contains errors.

[0010] In addition, there is a need for space-saving gas supply equipment, but installing an accessory device for flow measurement will hinder space-saving

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