FLOWMETER

摘要

PURPOSE: To improve the measurement accuracy of a flowmeter by closing a first chamber separately formed in a case by sticking a sealing lid to the end face of a dust collecting wall formed in the first chamber and the end face of the opening of the case and stably supplying a gas to be measured to a thermal type flow sensor in a second chamber through the leading-in hole and leading-out hole of a partition. CONSTITUTION: A gas to be measured is introduced to a gas passage 5 connecting a contracted section 5a to an expanded section 5b in a first chamber A through a leading-in section 2. The introduced gas is led to a leading-out section 3 side at the end of the passage 5 after passing through spaces between dust collecting walls 6 in a meandering state and dust and waste contained in the gas are collected to the walls 6. The first chamber A and a second chamber B formed by dividing the inside of a case 1 with a partition wall 4 can be closed when a sealing lid 9 and rear lid 17 are stuck to the case 1 with a bonding agent, etc. Part of the gas flowing through the passage 5 flows to a gas passing passage 15 surrounded by protruding edges and a circuit board 12 from a leading-in hole 7 and a thermal type flow sensor 13 on the board 12 measures the flow rate of the passing gas. After measurement, the gas flows to the passage 5 through a leading-out hole 8 and is discharged from the leading- out section 3.