For a general description of the process see 'Flow Monitoring'.
Introduction
Flow meters were utilized throughout the HMGA Water Project in order to determine water flows generated by processing carrots and other root vegetables. These values are used to properly size treatment equipment.
Introduction
Flow meters were utilized throughout the HMGA Water Project in order to determine water flows generated by processing carrots and other root vegetables. These values are used to properly size treatment equipment.
| Components The flow meters used included the Hach FL900AV meter with Hach Flow-Tote 3 AV sensor. The two components communicate with one another via a cable to measure and record. The Hach flow meters were chosen due to their reliability, ease of use, and their ability to determine flow in a variety of conditions. Often the water being discharged from the facility would have high solids content which would likely cause improper readings if other types of sensors had been used (mechanical sensors would likely get clogged/jammed for example). This flow sensor has three electrodes pointing out of the sensor base which are designed in such a way as to prevent the build-up of debris on the sensor. Pipe bands are used to secure the Flo-Tote 3 sensor inside an outlet pipe; they ranged in size from 8” to 14”, but other sizes are available. |  (Top left) Hach FL900AV meter and Hach Flow-Tote 3 AV sensor; (Top Right) Hach Flow-Tote 3 AV sensor with three protruding electrodes; (Bottom left) Sensor installed on pipe band; (Bottom right) Band and sensor placed in the discharge pipe. |
The Hach Flo-Tote 3, installed in a pipe, acts as the sensor which measures velocity and level of water. The sensor sends velocity and depth measurements through the cable to the Hach FL900AV meter which calculates flow and acts as a data logger. The data is stored for several days until it is downloaded to a computer. The Hach FL900AV meter is powered by four 6V lantern batteries. The unit is based on the principals of Faraday’s Law of electromagnetic induction. As the water moves through a magnetic field created by the sensor, it produces a voltage which is then recorded. The faster the water, the higher the voltage produced. Using the voltage, a velocity is determined. Flow is calculated by multiplying the velocity by the area of the pipe (Q=AV). The level of water in the pipe is measured using a pressure transducer. The transducer is made up of a thin diaphragm which converts exerted pressure to an electronic signal.
The software used to compile data, FSData Desktop Instrument Manager, allows the user to graph flow, velocity, and water level. An exporting function is also available to convert data to a .csv file which is compatible with Microsoft Excel. FSData is also used to calibrate the instrument at installation.
Limitations
The flow sensors could not be placed in pipes with a diameter less than 8” due to the width of the sensor, water would flow beneath the flow sensor due to the curve of the pipe. It can operate between -18°C to 60°C. The accuracy of the Flo-Tote 3 sensor was ±2% of reading.
Installation and Use
An appropriate band is chosen based on the pipe diameter. The Flo-Tote 3 sensor is attached to the band using screws and the cable from the sensor is affixed to the back of the band using zip-ties with ends snipped in order to have minimal effect on the flow. The sensor and band are then placed into the outlet pipe as far in as possible to minimize turbulence and create a streamlined flow. Lastly the sensor is connected to the logger.
The logger is then connected to the computer using FSData Desktop Instrument Manager. The Set-Up Wizard found within FSData requires the pipe diameter and current water level measurements be manually measured and inserted into the program. This is required once at initial start-up.
Logging measurements can be set at variable time intervals to suit the application; for example, readings can be taken every 60 seconds. In such cases, there is a need for greater program memory to capture data over longer periods of times. The data is collected by connecting the Hach FL900AV meter to a laptop computer via a cable.
Taking flow measurements in regular intervals provides a clear description of a set period of flow. Peak flows will be displayed as well as regular flow conditions.
Reference
The software used to compile data, FSData Desktop Instrument Manager, allows the user to graph flow, velocity, and water level. An exporting function is also available to convert data to a .csv file which is compatible with Microsoft Excel. FSData is also used to calibrate the instrument at installation.
Limitations
The flow sensors could not be placed in pipes with a diameter less than 8” due to the width of the sensor, water would flow beneath the flow sensor due to the curve of the pipe. It can operate between -18°C to 60°C. The accuracy of the Flo-Tote 3 sensor was ±2% of reading.
Installation and Use
An appropriate band is chosen based on the pipe diameter. The Flo-Tote 3 sensor is attached to the band using screws and the cable from the sensor is affixed to the back of the band using zip-ties with ends snipped in order to have minimal effect on the flow. The sensor and band are then placed into the outlet pipe as far in as possible to minimize turbulence and create a streamlined flow. Lastly the sensor is connected to the logger.
The logger is then connected to the computer using FSData Desktop Instrument Manager. The Set-Up Wizard found within FSData requires the pipe diameter and current water level measurements be manually measured and inserted into the program. This is required once at initial start-up.
Logging measurements can be set at variable time intervals to suit the application; for example, readings can be taken every 60 seconds. In such cases, there is a need for greater program memory to capture data over longer periods of times. The data is collected by connecting the Hach FL900AV meter to a laptop computer via a cable.
Taking flow measurements in regular intervals provides a clear description of a set period of flow. Peak flows will be displayed as well as regular flow conditions.
Reference
- Hach Company (2013). Flo-Tote 3 sensor: Open channel flow sensor – User manual. Retrieved from http://www.hachflow.com/pdf/Flo-Tote3Man.pdf on 22 June, 2016.
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