Open Channel Flow Open channel flow instruments are used to measure the waste water discharge from industrial and municipal premises. The measurement principal is documented in BS3680 where the head behind a restriction to the flow in either an open channel or tank fitted with a weir or vee notch plate. The restriction causes an increase in the liquid level proportional to the flow, the precise calculation depending upon the dimensions of the flume or weir plate in use. The level behind the vee notch or weir plate is usually measured by an ultrasonic transducer assuming the liquid is foam free and the mathematical calculations from level to flow being carried out in the instrument. It is usual for the instrument to display instantaneous flow usually in litres/sec a total flow converted to meters cubed which is non reset able a 4- 20 mA signal is usually provided for recording or data logging and a volt free contact for remote flow totalisation is a useful addition. We offer options of open channel flow meter to suit site requirements and specifications requested by the local authority or agency. In some instances it is more convenient to convert the discharge to use an in pipe flow meter we are able to supply. Open Channel Flow Measurement. Ultrasonic flow meters are for use on foam and steam free liquids MFLR Ultrasonic flow meter surface mounting displays both total and instantaneous flow at the same time. Fitted 3 relays and isolated 4 - 20 mA output, power supply 115/230 VAC supplied with RYT15 transducer Note the MFLR may also be used for level measurement over a range of 1 - 10 meters with 3 programmable relays for control and/or alarm purpose HR200 Mcerts Certified Hydroranger 200 Ultrasonic OCF meter for use in vee notch & weir tanks & flumes on foam free liquids. Displays total & instantaneous flow with a current output for data logging power supply 100 - 230 VAC. Vee Notch Tanks VNT Polypropylene Vee notch tanks can be made to order with SS vee notch plates. VNP30-SS Vee Notch Plate with 30° angle in 316 stainless steel VNP60-SS Vee Notch Plate with 60° angle in 316 stainless steel VNP90-SS Vee Notch Plate with 90° angle in 316 stainless steel Water Samplers PWS 1 Peristaltic water sampler to take flow proportional samples from flow meter.