CONE FLOW METER – PROFIBAR MATTECH®
Cone flow meters are based on the principle of differential pressure measurement, that is made by cone insertion in the pipe section. They are suitable for measurement of gas, steam and liquids flow, even for contaminated fluids or medium with content of solid particles, as well as for wet gases. The shape of the cone flow meter enables the flow of the contaminants and sludge contained in the measured fluid without their depositing in the pipeline.
As a standard, for the production of the cone flow meter there are used combinations of carbon and stainless steels for the measurement of fluid flows and refractory steel alloys for the measurement of steam flow. The cone flow meter is made within the range of nominal dimensions DN 50 to DN 500. This meter may be produced for larger nominal dimensions (max. DN 1000), however, in this case the meter shall be calibrated in test rooms by a fluid or a gas. Usually the flow meter is ended with a flange, designs for high pressures can be ended with a weld to eliminate possible leakage in the flange joint.
Cone flow meters advantage is that these are not relatively sensitive to usual flow disruptions and their low pressure loss. Requirements for minimum straight lengths are 3D to 6D upstream and 2D downstream the flow meter according to a specific calculation. The cone flow meter can be inserted both in vertical and horizontal piping.
Its disadvantage is its very demanding design, testing as well as production in comparison to standard types of flow meters such as orifice plates, nozzles or the Venturi tubes. It cannot be used as an approved meter with metrological verification, therefore it is produced as a working meter. Measurement uncertainty of the non-calibrated cone flow meter is relatively high as compared with other primary devices defined by ČSN EN ISO 5167 standard (for orifice plates, nozzles). If the meter is calibrated by a fluid or a gas in the test room, the uncertainty of the cone flow meter is comparable to these basic primary devices. For utilizations requiring higher measurement accuracies it is always recommended to calibrate the cone flow meter by a fluid or a gas.