A PRACTICAL ASSESSMENT OF THE PERFORMANCE OF ELECTROMAGNETIC FLOWMETERS

Over the last twenty years the electromagnetic flowmeter has come to be used in a variety of flowmetering applications. Accuracies of plus or minus 0.2 per cent may be achieved with this meter by using improved digital readout techniques. To achieve such accuracies it is necessary to carry out a wet calibration in an accredited test rig and apply meticulous care to the setting-up procedure and checking for zero drift in operation. NEL's many years of experience in calibrating and using electromagnetic flowmeters is summarized. A representative range of meter sizes is covered and typical calibration curves are presented. Results are given of the effects on the calibration of various pipe features adjacent to a detector head. These showed that the meter may not be independent of installation conditions. For example, the introduction of swirl to the flow produced a flow overestimation of approximately 1.5 per cent. An abrupt expansion at the meter entry also produces a noticeable calibration shift. When air was injected into the liquid stream, volume flow indications were apparently increased by 60 to 70 per cent while the reduction in mass flow was about 8 per cent. The use of the device as a flow monitor in hydraulic circuits is also included. /Author/TRRL/

• Corporate Authors:

  National Engineering Laboratory

  East Kilbride
  Glasgow, ZZ Scotland   
• Authors:
  • Scott, RWW
• Publication Date: 0

Language

• English

Media Info

• Features: Figures; Photos; References; Tables;
• Pagination: 15 p.

Subject/Index Terms

• TRT Terms: Accuracy; Building; Calibration; Electricity; Electromagnetism; Errors; Facilities; Flow; Flowmeters; Installation; Magnetic properties; Measuring instruments; Pipe; Sensors
• ITRD Terms: 6155: Apparatus (measuring); 6171: Calibration; 6954: Electricity; 6440: Error; 5430: Flow (fluid); 6936: Magnetism; 3361: Pipe; 6120: Sensor
• Subject Areas: Construction; Highways; Hydraulics and Hydrology; Maintenance and Preservation; I26: Water Run-off - Freeze-thaw;

Filing Info

• Accession Number: 00163150
• Record Type: Publication
• Source Agency: Transport and Road Research Laboratory (TRRL)
• Report/Paper Numbers: Paper E-1 Monograph
• Files: ITRD, TRIS
• Created Date: Mar 14 1978 12:00AM