Manufacturing plants, public utilities, power stations, oil & gas processing facilities and sewerage plants all have some form of industrial outflow which needs to be monitored and reported on. Hydro Power companies need to measure the volume, temperature and quality of water passed back into the river after it has passed through the turbines.
Traditional coal or gas power stations have cooling water discharges which need to be monitored, to ensure the temperature being returned to a lake or reservoir is not above acceptable limits.
Sewerage plants must measure and record any effluent from sewer treatment plants which is being discharged back into the environment.
Typically measured parameters for industrial outflow are water temperature, flow, depth, acidity, alkalinity and salinity. Monitoring instruments are generally deployed in outflow pipes or channels. There are various methods to measure flow and depth. For example, water flow can be determined using mechanical flow measurement devices like piston flow meters, turbine flow meters, single or multiple jet flow meters. For measuring depth, hydrostatic depth probe or simple float and pulley system will give stable and acculturate readings.
For this application Unidata offers all-in-one instrument Starflow 6526. Water velocity is measured by the ultrasonic Doppler principle which relies on suspended particles or small air bubbles in the water to reflect the ultrasonic detector signal. Water depth is gauged by a hydrostatic pressure sensor, referenced to atmospheric pressure through the vented power and signal cable. Starflow determines the actual flow mathematically based on the entered channel/pipe geometry and dimensions.
Starflow can be deployed in rivers and streams, open drainage channels and large pipes. For measurement of other parameters, water temperature, water quality for example electro conductivity (EC), pH (PH), dissolved oxygen (DO) can be measured with separate instruments. In some instances turbidity of the water / outflow may also be measured. The 6526 Starflow instrument would typically be installed at the base of the outflow channel using a provided mounting bracket, the instrument cable would connect to a power source housed inside a small enclosure usually located at the side of the channel.
It is important to consider power requirements of the site. If primary power is available, only a small battery would be added to the system to act as a backup, in case primary power is disrupted. If primary power is not easily accessible, the system can be powered by a lithium battery pack or rechargeable solar power system.
Depending on the instruments chosen, a lithium battery pack (non- rechargeable) can provide independent power source for up to 2 years. A solar power system consists of a rechargeable lead acid sealed battery, a solar panel and solar controller. The solar power system should be properly rated for the instruments used and as such will provide a long-term power solution.
Starflow and other instruments can be connected to a Neon Remote Logger via SDI 12, analog or digital inputs. Logger will scan / collect readings from the sensors on regular, custom specified, intervals.
It will check for any unusual out of limits readings and send data to a central Neon Server or an email or sms message to the appropriate people to take action following an out of limit condition. Logged data or alarms are sent using a cell phone modem or satellite modem depending on network availability. Data is then displayed on a web browser to be viewed or could also be sent, perhaps once per minute, via web services or FTP to other processing systems.
Source:Unidata Official website
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