| 摘要 |
<p>PURPOSE:To enable a high-precision measurement in accordance with the flow by a method wherein a rod-shaped vortex generator having two wires arranged symmetrically is placed in a pipeline to provide the functions of both a hot-wire current meter and a Karman vortex flowmeter, which are used selectively. CONSTITUTION:The wires 6, 7 are fitted to L-shaped and T-shaped support members 4, 5 of the vortex generator 1, and electrodes 4a, 4b, 5a are fitted to the wires 6, 7. When heating circuits 9, 10 function to heat the wires 6, 7, variable voltage signals V6, V7 corresponding to the voltages between the terminals are outputted. The first detecting circuit 11 picks up a signal Q corresponding to the differential signal V7-V6, and outputs a signal Q' which is synchronous with the period of the generation of the Karman vortex. The second detecting circuit 12 outputs an analog signal P' corresponding to the average flow velocity which is obtained by averaging the voltage signals V6, V7. The signals Q', P' are changed over by a change-over circuit 13 in accordance with the pulsating condition of the flow, and a predetermined display is provided. Accordingly, the flow rate can always be measured accurately, that is, it is measured through the frequency or period of the pulse signal Q' when the flow is steady, and through the level of the analog signal P' when the flow is pulsating.</p> |
