STUDY OF EDGE SHARPNESS EFFECTS MEASURED DURING THE EEC ORIFICE PLATE COEFFICIENT PROGRAMME
The EEC Orifice Plate Coefficient Project is being carried out under the joint sponsorship of the Commission of the EEC (the European Economic Community), and a number of participating organizations who are directly interested in the use of orifice flowmeters for the accurate measurement of natural gas. To check the continuing acceptability of the EEC orifice plates to the ISO-5167 Standard, the plates themselves have been the subject of numerous physical examinations. Of all the manufacturing requirements associated with the orifice plate and the meter run, one that has been found most difficult to check, and hence to achieve, is the sharp square edge of the plate itself. In the past there has been a tendency to accept sharpness as being adequately achieved when it appears sharp to the naked eye, despite various published papers demonstrating that an imperceptible blurring of the edge has been found to have dramatic effects on the discharge coefficient (i.e. up to 1% or more). The background of how edge sharpness has been specified in the Standards is given. The EEC Project has involved the use of a number of different techniques which are described and the results compared. It is concluded that a more objective method of measuring the edge profile must be adopted universally.
Bibliographic Reference: EUR 11131 EN (1987) MF, PP 36, BFR 150, BLOW-UP COPY, BFR 200, AVAILABILITY: CEC-LUXEMBOURG, BP 1003, GDL
Availability: Can be ordered online
Record Number: 1989126062200 / Last updated on: 1989-05-01
Available languages: en