| 摘要 |
<p>PURPOSE:To expand the measurable flow rate range of the title sensor so that the sensor can measure large flow rates by forming a sensor pipe to have a relatively large wall thickness by setting the outside and inside diametral dimensions of the pipe to have a ratio larger than a specific ratio. CONSTITUTION:The quantity of heat which is removed from an upstream coil 7 by means of a fluid flowing through a sensor pipe l and the quantity of heat which is given to the pipe l from a downstream coil 8 vary depending upon the heating temperature and mass flow rate, but the temperature change of the pipe 1 caused by the quantity of heat given to the pipe 1 becomes smaller as the wall thickness of the pipe 1 increases and the movement of the temperature distribution from the upstream side to the downstream side also becomes smaller as the wall thickness of the pipe 1 increases. Since the movement of heat can be accurately detected when the movement of the temperature distribution is within the extents of the wound sections of the coils 7 and 8, larger flow rates can be detected as the wall thickness of the pipe 1 is increased. Accordingly, the pipe 1 is formed to have a relatively thick wall thickness by roughly setting the ratio of the outside diametral dimension D0 of the pipe 1 to the inside diametral dimension D1 of the pipe 1 within a range of 1.5<=D0/D1<=4.0 by paying attention to the balance among the kind of fluid, desired flow rate range, and responding speed. Therefore, the allowable flow rate limit can be increased.</p> |
