| 摘要 |
<p>PURPOSE:To highly accurately measure the flow rate of a fluid running in a main flow path by preventing the generation of a back flow at a bypass flow path even at the occurrence of the back flow at the main flow path. CONSTITUTION:If the flow of a fluid runs in an inverse direction, such a flow as indicated by an arrow E is temporarily brought about. At this time, the flow E stagnates at a point (a) where it collides against a curved expanding part 4B. The pressure at this point becomes high, and the pressure at the other peripheral surface (b) of the expanding part 4B becomes lower than that at the point (a). The pressure at the peripheral surface (c) of an entrance member 4A is increased again because of the stripping action of the flow. Since the shape of the expanding part 4B influences the back flow E of the fluid running in the vicinity of the expanding part 4B, the pressure at the surface of the expanding part 4B is made smaller in the outer periphery of a hole 5 formed in a direction different from an axial direction of a main flow path 2 than the pressure at the entrance of a bypass flow path 3. Therefore, even if back flows D, E are generated at the main flow path 2, they rarely enter the flow path 3. The characteristic of the flow velocity measured by a flow velocity measuring member 6 is never influenced by a back flow even if it happens.</p> |
