| 摘要 |
PURPOSE:To always accurately keep measuring accuracy high even if the sharp change in a flow amount is generated, by automatically performing the opening and closing of a bypass flow channel by a diaphragm. CONSTITUTION:When it is assumed that a flow amount gradually increases from zero, a governor value C holds a full closed state because differential pressure P1-P2 is low at first and a fluid is flowed from an upstream side measuring part A to a downstream side measuring part B and the differential pressure P1-P2 rises from a point (a) to the point (b) corresponding to first set differential pressure DELTAP1 and rises from the point (b) to a point (c) by the closed valve holding action of a magnet 22. When the differential pressure P1-P2 reaches second set differential pressure DELTAP2, a diaphragm 17 is moved to the position where the attraction of the magnet 22 is released and a main valve 16 is opened to hold the differential pressure P1-P2 to the first set differential pressure DELTAP1 and the differential pressure P1-P2 is lowered from the point (c) to a point (d). The differential pressure P1-P2 is kept constant at the beginning by the change in the opening degree of the governer valve C corresponding to a low amount and slightly rises after the governer valve C was fully opened at last to change from the point (d) to the point (e) corresponding to a max. flow amount.
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