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Straight pipe requirement
This is one of the most common mistakes in flowmeters installations. some electromagnetic flowmeters manufacturers specifies 3X or more of straight pipe before and after the flowmeter. This requirement is more important in the case of turbine flow meters since it directly changes the speed of which the turbine rotate. not following this requirement will degrade the accuracy of the flowmeters, we have noticed an error up to 0.7% on some installations of flow meters that has accuracy of 0.2%. Grounding Electromagnetic noise can generate errors in flow measurements. Motors electromagnetic field is one of the sources of this noise. Grounding is important and always overseen in most electromagnetic flow meters installations. Most importantly grounding the liquid that passes through the flow tube. Connecting ground to the board is not enough in most cases, most flow meters has an additional grounding terminal on the side of the meter, and in some cases (i.e. when using plastic pipes) it is required to install grounding rings. |
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