| 摘要 |
<p>A flow meter for use with a fluid source (12) includes a chamber (28) of known volume, and level sensors detecting fluid boundaries at either end of the known volume. A valve (36) between the fluid source (12) and chamber (28) is opened at a defined time until fluid level within the chamber (28) rises above the upper sensor, whereupon the valve (36) is closed. As the fluid level falls past the upper sensor a second time level is measured, with both time intervals being terminated as the level falls to the lower level sensor. The average flow rate as the fluid falls between the two sensors is calculated by a computer, and the total volume is then calculated using the longer measured time interval. Flow rates over long time periods can be accurately measured.</p> |
