| 摘要 |
PURPOSE:To accurately measure a flow rate of gas at a low cost, by measuring the variation of received quantity of light of a reflection body provided to a rotating body varying the speed in accordance with the flow rate of the gas. CONSTITUTION:The speed of a gaseous flow from a gaseous flow inlet 23 is accelerated by a nozzle 22 and the gaseous flow strikes on a blade of a rotating body 25 and then, the body 25 is rotated at the rotatioal number in accordance with the flow speed. A reflection board 26 of the body 25 reflects a light from a luminous body 30 having a constant luminous energy through an optical fiber 28. This reflected light is received by an optical fiber 29 connected to a control part 31 and this received quantity of light is photoelectrically converted. The gaseous lows flow rate can be detected as the received quantity of light by measuring the relation between the flow rate and the rotational number preliminarily, so that the received quantity of light is proportional to the rotational number of the body 25 and the number of the board 26. Accordingly, the accuracy of measurement can be more heightened by accelerating the rotational number and increasing the number of reflection boards. |
