Open channel flow is the measurement of waste water discharge normally from indu strial premises to a sewer or water course.
Open channel flow monitoring or outflow monitoring is normally a condition of a consent to discharge agreement. Commonly the instantaneous flow in litres per second and the totalised flow in metres cubed (m3) are the minimum requirements for a consent to discharge agreement.
The flow measurement normally takes place in a V-Notch tank which is a convenient way of both providing a restriction for the accurate measurement of the flow rate as well as a mounting point for additional sensors such as pH, Temperature, Turbidity and / or other parameters which may be designated in a consent to discharge agreement.
The V-Notch tank is so called as it includes a "V" shaped weir or notch on the outlet of the tank. The measurement principal is outlined in BS3680 - the V shaped notch causes a restriction which results in an increase in the height of the liquid in proportion to the flow rate.
The precise calculation depends upon the dimensions and angle of the V-Notch plate. By accurately measuring the height of the liquid over the V-notch we can accurately extrapolate the flow rate of the liquid.
The height of the liquid is normally measured by an ultrasonic flow meter, this incorporates a microprocessor which calculates the flow rate from the measured height. In addition we are able to supply calibrated and certified instruments to ensure compliance with MCERTS.
We strongly recommend that ultrasonic type flow meters are installed on foam free liquids.
Our V-Notch tanks are custom manufactured in polypropylene and fitted with a V-Notch plate with an angle suiting the flow rate of your application.
In addition to measuring the flow rate - the V-Notch tanks can be manufactured to allow a number of mounting points. Commonly these allow a dip pH probe, turbidity sensor, or temperature sensor to be mounted into the tank to provide final effluent discharge readings. Other sensors can also be provided a mounting point if required.
We offer a wide range of V-Notch plates to mount into our V-Notch tanks. These are manufactured in 316 Stainless Steel and laser cut to provide a precision angle. The range of angles we provide include 30º, 60º and 90º to suit a wide range of flow rates. If you need assistance in choosing a v-notch plate then pleased don't hesitate to get in touch.
Our open channel flow measurement systems are available with industry standard 4-20mA outputs which can be incorporated into a 3rd party BMS or PLC system. We also offer our own data logging solution with local units offering local monitoring as well as our online data logging solution to provide realtime measurements and cloud storage.
Ultrasonic flow meters designed to be mounted above V-Notch tanks to provide accurate flow measurements.
When combined with a suitable V-notch tank the ultrasonic flow meter range calculates the instantaneous flow (litres / second) and totalised flow (m3) by measuring the change in level caused by an increase in head behind the v-notch plate restriction.
Designed for waste water and effluent discharge monitoring applications the MFLR can be easily integrated into a chart recorder, data logger, or online data logger to comply with consent to discharge agreements.
V-Notch Tanks are manufactured in polypropylene to suit your requirements.
We offer tanks suitable for internal or external mounting, with sizes based on your forecasted flow rate and any restrictions on the space available.
Depending upon your consent to discharge requirements we offer a range of mounting options for pH sensors, Temperature Sensors, Turbidity sensors and can accommodate sensors to measure other parameters as required.
We have a range of laser cut stainless steel V notch plates for mounting into our V-Notch tanks. These are precision engineered to ensure a true angle of restriction available with 30°, 60° and 90° V-notch angles.