Open Channel Flow Meters – Non-Contact, Area Velocity
Pulsar’s MicroFlow, FlowCERT and dBMACH3
MicroFlow
MicroFlow provides a non-contacting, velocity measurement solution for open channels. Use MicroFlow as a stand-alone device for simple velocity measurement or pair it with a dB Ultrasonic Transducer for a complete area-velocity system.
Area-velocity calculations using MicroFlow provide a cost-effective flow measurement solution compared to the installation of a Primary Measuring Device (PMD). Additionally, the hydraulics of a site can sometimes not allow for restriction within the channel, therefore it would be unsuitable for a PMD to be installed, the MicroFlow provides a viable solution
For channels less than 1.5 m (4.9 ft) wide, MicroFlow can be combined with the dBMACH3 flow transducer (or another dB Transducer) and a FlowCERT controller to gain accurate area-velocity readings.
For larger channels such as rivers or effluent flow channels that are more than 1.5 m (4.9 ft) wide, more than one MicroFlow should be used to provide improved measurement, averaged across the wider flow profile, with the selected dB Transducer and an Ultimate Controller for an area-velocity flow system that averages the velocity from multiple sensors across the channel, ensuring accuracy in difficult to achieve straight-run conditions.
The MicroFlow sensor uses K-Band radar technology and Pulsar Measurement’s unique analysis software takes readings from the whole width of the channel. If more than one MicroFlow is being used, an average reading will be calculated back in the control unit. To gain the most accurate and reliable reading, the end-user should make sure that the MicroFlow unit is mounted at 45 degrees to the water surface.
The K-Band radar technology works by using short pulses of microwaves, which are transmitted by an enclosed antenna on the face of the unit. When reflected off a moving surface, the signal experiences a shift in frequency characteristics. The reflected signal is captured by the onboard microprocessor via the antenna and analyzed to determine the velocity.
FlowCERT
Pulsar Measurement’s FlowCERT provides comprehensive open channel flow measurement with extensive data logging and control functions. It includes a range of pre-programmed flumes and weirs, so setup is quick, simple, and straightforward. The unit is compatible with a range of both contacting and non-contacting sensors and has the flexibility to change with your application.
FlowCERT gives temperature-independent, reliable measurement and logging facilities. The unit includes five alarm/control relays plus 4-20mA output, data logging, and digital input with the ability to accept a velocity sensor input for non-PMD applications.
Area-Velocity Measurement / Open Channel Flow Measurement with No Primary Measuring Device
FlowCERT can be combined with a MicroFlowfor velocity measurement. Or for area-velocity flow measurement, FlowCERT can be used with a MicroFlow and dB Transducer for a non-contacting solution.
Open Channel Flow Measurement with a Primary Measuring Device
When you have an application with a Primary Measuring Device (PMD), FlowCERT can be combined with dB transducers up to a dB15.
Data Logging
Pulsar Measurement’s Data Logger provides wall-mounted Ultra Controllers with data logging functionality. The logger records a wealth of information onto the supplied 32GB Micro SD card enabling you to log a wealth of data for the lifetime of the unit. Log interval is user-selectable and logged files are stored in .csv format which can be used with the most widely used spreadsheet software.
dBMACH3
Featuring unique sun and submergence shields, the dBMACH3 is designed specifically for open channel flow applications. dBMACH3 is the first ultrasonic transducer with zero effective blanking distance beyond the nose cone, allowing it to be sited at little as a few millimeters from the high-flow level. One of the critical factors affecting the ultrasonic accuracy is the measurement distance, so by minimizing the distance, accuracy is maximized.
Operating at 125 kHz frequency the transducer provides high resolution and accuracy. Essential in open channel flow applications. The dBMACH3 can be used with the Ultra 4, 5 and TWIN when in open channel flow mode, or can be paired with the FlowCERT, all of which provide a typical accuracy of +/- 1 mm. Resolution +/- 0.5 mm. Range 0 mm to 2.4m.
