How to Calibrate Balances and Scales

How to Calibrate Balances and Scales

Why does my Balance need Calibration?

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Many people have questions concerning whether or not a balance or scale needs to be calibrated.

The short answer is Yes! Scales and balances, in fact all modern instrumentation, need to be calibrated to ensure that they are in compliance with the specifications quoted. Having said that, how often to calibrate is more vexing to establish.

Firstly, consider at delivery. If you purchase through a scale or balance dealer locally, he will most likely deliver the balance and install the equipment. At that time, he or she will calibrate the balance using a good class of certified weights. If you purchase online, you will need to accomplish the calibration yourself, or bring in a scale dealer or calibration house to do this initial calibration.

But, I hear you ask, surely, the balance was calibrated by the guy who sold it to me. Well, that seriously depends on who you purchased from and what model of balance or scale we are talking about. Many “suppliers” simply move boxes. They get the box in from the manufacturer and they move the box out as soon as possible. A UPS label or FedEx label is applied and off it goes.

That doesn’t help you as the balance has been on the “Trains, Boats and Planes” trip for some time and God only knows what has happened to it in the meantime. Errors are easily introduced by rough handling.

We, at Intelligent Lab, will have removed the instrument from the box, inspected, calibrated and carefully ensured that all the parts are contained within the box, before lovingly committing the box to FedEx or UPS, maybe even the United states Postal Service.

So, no need to worry, is there?

Well, I am afraid that is not the end of the story. You may remember from school geography lessons that the earth is not round, but slightly doughnut shaped. The differences in latitude and height make a difference in the amount of earth between you and the center of the earth. This affects the gravity value. Therefore, when we ship a calibrated balance from say, California to Maine, the gravity working on the balance is slightly different in Maine, therefore the reading on the balance will be different than in California.

That is why the majority of our balances have test weights supplied as standard. You can effect a calibration yourself. Note, our calibration weights supplied are not normally certified weights, due to cost considerations, but our weights are tested against them and will give you much better results than just working with a non-calibrated balance.

Okay, so your balance has now been calibrated. How often should you do this? The short answer is as often as is practical. If the balance gets heavy use, perhaps once a week is sufficient, if lightly used, once a month would be OK, but the more often you calibrate the less uncertainty there will be. Finally, WHENEVER you move your balance or scale, it should be recalibrated in the new position. This is a must.

Richard Sharpe 2014

By | 2014-01-13T08:58:34+00:00 January 13th, 2014|Calibration, Laboratory Balances, Scale Maintenance, Scales and Balances|Comments Off on How to Calibrate Balances and Scales

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