| 摘要 |
PURPOSE:To measure flow speed highly accurately even in a high speed range by deviding the energizing frequency of an energizing coil into >=2 kinds of frequency in accordance with flow speed ranges to increase the frequency in proportion to the increment of flow speed and shorten the rise time of magnetic flux. CONSTITUTION:An electromagnetic flowmeter consists of an electromagnetic flow rate detector 1 and an electromagnetic flow rate converter 6a. Three measuring ranges are previously set up in a span setter 8a, and receiving three synchronizing signals proportional to these ranges from a synchronizing signal generator 10a, an energizing electric power generator 11a changes energizing current, voltage and frequency and rise time in proportion to the increment of flow speed to apply magnetic flux to a measuring tube 3. A signal proportional to the flow speed of fluid is taken out from an electrode 3a and converted into a measuring range proportional to the flow speed by the span setter 8a through a preamplifier 7 and the converted signal is inputted to a coverter 9 with a synchronizing sampler. An output signal 14 is outputted from the converter 9 by a signal from the synchronizing signal generator 10a. Consequently highly accurate flow speed can be measured even in a high speed range. |
