Product description
In cases where the conditions are similar to those in water-supply systems, we may choose from among the "standard" flow meters such as magneto–inductive or ultrasonic flow meters. The most important conditions are fully filled flow cross-section (full pipe) and the upper limit for particle content (about 10%).
Flow measuring in open channels and partially full pipes
The conditions for the so-called "free flow" are met each time the streaming fluid has a free cross-section open towards the atmospheric pressure. Therefore, the only force driving the flow in such systems is the gravitational force of the fluid. As a consequence, with a steady flow in the direction of the free outlet, the level of the fluid is progressively lowered.
One of the most common solutions, which is used for waste water (fluid) flow metering, still remains the indirect method of determining the flow — by measuring the difference in height (h). The measuring device essentially consists of two parts:
- Level gauge / fluid height gauge: hydrostatic, ultrasonic, or radar measuring principle;
- Primary structural element in a form of a weir or a channel section of a specific profile:
V-weir, rectangular weir,
Venturi flume, Parshall flume, Palmer–Bowlus flume.
Choosing the correct primary element depending on the conditions at a measuring site and the measuring requirements, and its correct installation are the most important factors for guaranteeing an acceptable measuring uncertainty.
Application:
Commonly used for measuring the flow of surface waters, and the industrial wastewater in sewer pipes and conduits. Weirs are used in water streams / outlets with low particle content. The flumes are more suitable for fluids with high particle content. Usually, the biggest cost is incurred by the construction works for the water meter chamber.
We also offer complete measuring systems made by Badger Meter GmbH, or only a supply of the primary channels, and installation of standard V-weirs.
Magneto–inductive flow meter Parti-Mag II (FXP4000)
In addition to other flow meter types, ABB Automation also produces flow meters for partially-full pipes, envisaged for classic installation into pipelines with flanges. The meter uses a well-established magnetic induction principle, and the additional electrodes enable determining the average flow velocity through a defined cross-section. At the same time, the electrodes – using additional AC-field – measure the vacancy of the pipe.
Features:
- For sizes from DN150 to DN2000,
- Accuracy:
3-5% of the total flow rate at partially-filled pipe
1% vrednosti pretoka pri polni cevi, - minimalni nivo zapolnitve 10% pretočnega premera merilnika,
- za prevodnosti med 50 mS/cm uin 10.000 mS/cm,
- Ex certifikat
