| 摘要 |
PROBLEM TO BE SOLVED: To reduce an error of measurement precision due to continuous great fluctuation of a flow rate. SOLUTION: A flow rate measurement device is provided with a fluid flow passage having a high flow rate passage 205 and a low flow rate passage 204, a movable valve 203 regulating a gas flow rate to the high flow rate passage 205, a diaphragm 207 working integrally with the movable valve 203 and receiving an upstream gas pressure of the fluid passage applied to one side through an upstream pressure chamber 214 and a downstream gas pressure of the fluid passage applied to the other side through a downstream pressure chamber 213, a low flow rate measurement means 201 outputting a low flow rate signal matching a flow rate of fluid flowing though the low flow rate passage 204, and a high flow rate measurement means 202 outputting a high flow rate signal matching a flow rate of fluid flowing thought the high flow rate passage 205. This flow rate measurement device is also provided with an attenuation means 220 reducing at least one of a sequential pressure change of the upstream gas pressure matching an instantaneous flow rate change transmitted to the upstream pressure chamber 214 and a sequential pressure change of the downstream gas pressure matching an instantaneous flow rate change transmitted to the downstream pressure chamber 213.
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