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Starflow, the low cost solution for open channel flow metering

Starflow, a flow meter and a complete hydrographic data collection system. Unidata’s water flow meters provide inexpensive, and reliable pipe and open channel flow metering.

The Starflow ultrasonic flow meter is a unique combination of water velocity, depth and temperature sensors integrated with a micro logger, all contained in an underwater casing only 25mm high! The versatility of this water flow meter allows both open channel flow measurements in clean fresh streams as well as waste water measurements in partly filled pipes. It can be set up to compute both flow rate and total flow, and includes a fully programmable control output suitable for triggering water samplers or alarms, for example in the event of flood.

The constituent parts of an ultrasonic flow meter are a hydrostatic pressure sensor for measuring depth, a temperature sensor, and an ultrasonic transmitter/receiver pair for measuring water velocity. These are all controlled by a datalogger, which records data as specified from the scheme created by the user software. A single cable links the submerged instrument to a weather-proof polycarbonate enclosure which provides a data download point, and where the battery is stored. The enclosure has an optional LCD display.

The flow meter is mounted on (or near) the bottom of the stream/pipe/culvert and measures velocity and depth of the water flowing over it. Normally it is faced upstream and reports positive flow but it is a bi-directional instrument capable of measuring reverse flow.

Starflow is designed for battery operation, and battery life will depend on the frequency of measurement (the scan rate can be set between five seconds and five minutes), and the logging interval (the period of time between readings being recorded to memory can be set between five seconds and seven days). In a typical installation, its 12V 12Ah rechargeable battery will provide over six months of continuous recording at a log interval of five minutes, with hourly logging. The system can alternatively be permanently powered from a solar panel or mains derived DC, if required.

Starflow comes complete with software (Starflow V.3) designed to operate on all PC compatible computer systems. Starflow V.3 is used to configure the instrument and create the required data collection and management system by creating a “Scheme” which will be unique to the site. The required inputs are made using a series of dropdown menus and windows in which parameters such as scan rate, log interval, and type of installation (for example pipe or open channel) are entered. A simple project should take less than ten minutes to define and make Starflow ready for operation.