| 摘要 |
An apparatus includes a conduit having a generally circular cross-section, and a liquid flow sensor extending into the conduit so that a liquid contacting portion extends generally parallel to an axis of the conduit and is positioned to extend into an interior of the conduit a first distance. An electromagnetic coil is positioned in the housing for generating a magnetic field within the liquid flow. In addition, the sensor includes a pair of spaced apart electrodes defining a second distance therebetween and being exposed on the liquid contacting portion for generating a signal related to the liquid flow rate. Moreover, the second distance is preferably greater than or equal to about two times the first distance and is greater than or equal to about one-tenth a diameter of the conduit. An open channel embodiment of the invention has a cross-section of a predetermined width and an opening in a bottom wall thereof. A liquid flow sensor is positioned in the opening in the open channel. The liquid flow sensor is as described above. In this embodiment, however, the pair of spaced apart electrodes preferably define a distance therebetween being in a range of about 0.10 to 0.95 times the predetermined width of the open channel. This relationship ensures acceptable accuracy using a relatively compact, lightweight and relatively inexpensive sensor. Method aspects of the invention are also disclosed.
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