| 摘要 |
PROBLEM TO BE SOLVED: To provide a flow meter for reducing the pressure difference between an internal pressure and an external pressure within a box maintained while the box for accommodating a flow rate indicating mechanism is maintained surely and airtightly, changing airtight state within the box in two steps at a fixed level or higher, and stably maintaining the airtight state at the fixed level or higher for a long time. SOLUTION: In the flow meter, the box 5 is pressed against and held by fixing an upper case 1 and a lower case 7, in a state where a transparent shielding member 3 is assembled by an assembly member 2 via a sealing ring 4. If the assembly member 2 is fitted to the box 5 and rotated about the central axis line O, engagement sections 23, 55 are engaged with and fixed to each other, the sealing ring 4 are compressed, and the interior of the box 5 goes into an airtight state. The sealing ring 4 is additionally compressed by fixing the upper case 1 and the lower case 7, and the interior of the box 5 goes into a high airtight state. COPYRIGHT: (C)2008,JPO&INPIT
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