| 摘要 |
<p>PURPOSE:To measure a flow rate extending from a large flow to a small flow without lowering accuracy by providing the device consisting of a main pipe line and a measuring pipe line, and providing a means to change flow ratio of the main pipe line to the measuring pipe line. CONSTITUTION:The measuring device is constituted of a main pipe line 2 letting flow fluid, and a measuring pipe line 3 branched from the pipe line 2 and letting flow fluid. The outer circumference of the measuring pipe line 3 is wound with a heating resistor 31 in the upstream and a heating resistor 32 ;in the downstream and a mass flow flowing in the measuring pipe line 3 is measured by means of the resistors 31, 32. Fluid flowing in the inlet 4 of a mass flowmeter 1 is separated to the main pipe line 2 and the measuring pipe line 3, and made together in the vicinity of the outlet 5 again. A valve 21 is provided in the main pipe line 2, the valve 21 is moved right and left by the action of an actuator 22 so as to open/close the main pipe line 2, and flow ratio of the main pipe line 2 to the measuring pipe line 3 is controlled.</p> |
