Flow measurement in open channels
Until a few years ago flumes and weirs were widely used but involving committed works, partially or total invasive in to water river beds or embankment. With the Doppler ultrasound technology, we overcome restrictions and contraindications.
By the submerged or insertion wetted sensors categories together radar surface contactless, combined with an microprocessor monitoring electronic, we control, measure and record the basic hydrodynamic parameters such as level, flow rate and total flow of water channels, reservoirs, gutters, sewers, etc.
An acoustic waves train is sent and received simultaneously by one transducers couple mounted inside the sensor at a programmed frequency. Due to interfering with the solid particles or gases microbubbles in to the water stream the Doppler ultrasound flowmeter calculates the average velocity of the fluid media. The algorithm takes in account two main variables velocity and depth.
The Doppler sensors by submersion installation works at the center of channel, just above the bottom side. In many situation, one support arm can allow easy placement at desired depth quote, and at the center of median vein, from a dry point above on ground.
The velocity profile is determined for the entire section area, thanks to the second embedded sensor that measures the water column depth in to the channel, the electronic modular cards mounted in the stand alone unit AGR3PRO or FLD3PRO models, calculate and record data on timing from multiple sensors inputs and retransmit the results to a local PC or to a remote internet host via GSM/GPRS bus. So the data files stored in memory can be exported in any spread sheet.
The software supplied with the instrument is intuitive and easy to learn. This allows to modify the initial configuration, for example, to move the sensors from one installation to another, with a simple reprogramming. The utility supplied, calculates the area of the measuring section, adapting it to the morphologies and geometries of the channel. Instantaneous amount of flow rate is determined by integration single velocity stream per area cross section portion of the channel.
- The Doppler method is experimentally very accurate. Typically it maintains accuracy within +/- 2% of the instantaneous measured value.
- Installation range vary widely, with depth measurement from 25 mm up to 10 meters, thus suitable for measurement in the gutters, drains, irrigation canals, shallow water, irrigation ditches, etc.
- Reduced installation costs. No need for masonry work, dedicated infrastructure otherwise necessary with traditional primary measurement elements such as weirs, Parshall flumes or equivalent.
- Our Doppler sensors even by insertion that immersion require a shorter straightness portions.
- The reduced invasiveness and low barriers limit the flow tendency to cover the sensor by silt, sediment, and animal or vegetable fats, making the sensors free of periodic maintenance.
- Ability to analyze data of flow rate and totalized flow for environmental controls and energy consumption, pump efficiency, etc.
- Our devices are provide pre-configured in according to commissioning for the user needs and shipped ready for field installation.
Posted in: Technologies and instruments evaluation