Class 0.2 belt scale is here, are we ready?

[Abstract] The International Organization for Legal Metrology is about to release a new version of OIML R50 International Recommendations. This version adds an accuracy level of 0.2. In this regard, problems that may occur after the new version of R50 is issued and implemented, and recommendations for increasing durability tests.

[Keywords] R50; durability; durability simulation test

Foreword

In November 2014, the International Commission for Legal Metrology (CIML) held its 49th meeting in Auckland, and passed the “Continuously Cumulative Automatic Weighing Instrument ( Belt scale)” the latest international recommendation (R50-2014-fd). This version of R50 adds 0.2 level to the accuracy level of the belt scale. Speaking of this modification, it can be traced back to May 2009, when Adrian rudd, deputy dean of the British National Institute of Legal Metrology, and Gavin Stones, the Minister of Certification (Note: The secretariat of OIML TC9/SC2 is located in the British National Institute of Legal Metrology). When I participated in the 2009 Shanghai International Weighing Apparatus Exhibition, I was informed that the "array belt scale" t has an accuracy index of 0.2, so I visited Saintbond company.

After visiting and inspecting the "array belt scale" and the "belt scale full performance laboratory" of Saintbond, Saintbond Company put forward a suggestion to TC9/SC2: an increase of 0.2 level. The reason is: Our products have reached the 0.2-level indicator, and the international recommendations are lagging behind and should be revised and increased.

In April 2011, Saintbond participated in the R50 seminar of the International Legal Metrology Organization for the first time as a Chinese enterprise. At this time, TC9/SC2 has adopted the proposal of Saintbond. The accuracy of 0.2 level has been added to R50-2009 3CD. Whether the belt scale in R50 should be set to a level of 0.2 has always been controversial at home and abroad. TC9/SC2 had written the accuracy of 0.2 level into the revised manuscript during the previous revision (1994). In the subsequent discussion, it was difficult to guarantee the belt scale because of the large impact of the belt conveyor on the belt scale. Long-term stability. The final version of R50-1997 still deleted the 0.2 accuracy level.

Now that this proposal initiated by a Chinese company is about to be realized, it is indeed exciting. However, apart from the excitement, the author can't help but feel a little worried: the 0.2-level belt scale is coming soon, are you ready for China?

1. A question to Chinese belt scale manufacturers: Are we ready?

As we all know, the reason why the belt scale has been criticized by users since its inception cannot be used in applications that require accurate measurement, such as bulk trade measurement. Its fatal weakness is: poor "durability", unable to maintain the nominal accuracy and verification time accuracy indicators for a long time. Without long-term stability, belt scales can of course not be used as trade weighing scales.