Ultrasonic flow meters measure the level in a channel by transferring a pulse of noise from the face of the sensor to the surface of the flow stream and measuring the moment for the echo to return. The transportation time represents the range between the face of the sensing unit and also the surface area of the water.

When the meter is at first established, a pre-determined range (or degree in some meters) is set. This range is either the zero degree (no flow existing) or a specific degree in the flume or dam. With this initial calibration it is only a matter of simple math to establish the fluid degree. This China radar level meter is then used to either pre-programmed discharge equations or strapping tables to result a circulation rate.

Ultrasonic sensing units have actually no scheduled upkeep due to the fact that the sensor is not in call with the water. Ultrasonic sensing units are not impacted by chemicals, grease, put on hold solids, or silt in the flow stream.

Performance of ultrasonic flow meters might be degraded by:

- Strong wind
- Solar heating (of the sensing unit).
- Foam.
- Turbulence.
- Heavy steam.
- False echoes from blockages

To fight these troubles a range of methods are utilized:

- Sensing unit sunshades (for solar heating).
- Angling the sensing unit face (to decrease vapor condensate build up).
- Exclusive control systems are utilized to adjust amplifier gain (to raise resemble stamina).
- Variable blanking distances (to remove very early/ late echo returns).
- Wetting aspects (applied to decrease tops and also troughs in the result signal).

For maximum efficiency, ultrasonic circulation meters are not suggested for use on channels much less than 6-inches [15.24 centimeters] large (due to beam spread) or where vapor, foam, turbulence, floating particles/ oil/ grease are present (although as seen over these problems can occasionally be minimized).

To obtain optimal precision a temperature sensor [either indispensable to the ultrasonic sensing unit (preferred) or as a stand alone sensor] is required to compensate for modifications in air temperature level.

Dead period (the distance gauged from the face of the sensing unit in which sensor exhibits degraded efficiency) is generally 1-foot [0.3048 m], while the array for flow measurement sensors is normally as much as 11-feet [3.353 m]

Under common problems (still air, 40-70% loved one moisture, 72 ° F [22.22 ° C], the degree dimension accuracy of ultrasonic flow meters can ± 1/4 to 3/8-inch [0.635 to 0.9525 centimeters] (relying on the adjustment in degree).

When mounting a ultrasonic sensor over a flume (or weir) there is a tradeoff between accessibility (installing the sensing unit near the side of the flume) and maximum potential accuracy (placing the sensing unit over the centerline of the flume). If the circulation approaching the flume has been correctly conditioned and the flume appropriately established, either problem is appropriate. If, nonetheless, the circulation has actually not been properly conditioned, is disturbance, or is badly dispersed, analyses at the sidewall may vary from those in the center of the flume. Don't assume, though, that the centerline analysis is automatically more exact.