Whether you’re in the lab or field, precision matters when it comes to weighing aggregates, foods, pharmaceutical powders or other materials. You need precise measurements to ensure you’re complying with all the demanding QC/QA requirements and it can be challenging to find the best fit for what you need. How do you choose the right scale for your applications?
We’ve outlined some considerations you can use when choosing a scale, as well as the high-performance features you should be aware of when surveying your options. It’s our goal to help make the selection process easier for you!
What is the required capacity?
The total load placed on the scale must be within the rated capacity of the device to yield an accurate weight. Don’t forget about the weight of scoops or containers, although many electronic scales accommodate a tare weight separately from the rated capacity. A good rule of thumb is to select a scale that allows you to weigh your heaviest samples in the middle of its range. Applications requiring enhanced readability at higher capacities also require more sophisticated load cells, which increases cost.
What weighing units are required?
Some specifications require a specific unit of measurement such as grams, pounds, ounces, or grains. You should keep this in mind when selecting a scale, particularly if you’re looking at mechanical equipment. Modern electronic models frequently offer a wide range of user selectable units.
What is the minimum readability?
Some test methods specify a minimum readability for a scale. Readability is the smallest division of mass that the scale will display. For example, A scale with readability of 1 gram displays weights in whole grams, not decimals or fractions. The scale must be at least capable of meeting the minimum requirement, however, keep in mind that increasing readability too much may needlessly add expense to the scale of your choice.
Are you looking for a mechanical or digital scale?
Today’s digital scales are remarkably robust and resistant to dust, moisture, shocks and other environmental conditions, but it’s important to consider how and where you will be using the scale. If accuracy is not critical, you may want to consider a mechanical scale. On the other hand, if you need highly specific measurements, a digital scale may be the right choice for you because you’ll yield more precise readings. A digital scale also gives you more choices for weighing units, data handling and storage options.
What size pan or weighing platform is necessary?
Objects or containers being weighed must be fully supported by the pan or weighing platform. If samples hang over or extend beyond the platform, this could result in unstable readings or inaccurate results. It’s important to select a model that accounts for larger objects if necessary.
Do you need special features?
When considering what features are most important to you, it’ll be helpful to think about what your application requires as well as power and portability needs. This will help you narrow down the models with features for your purposes. We’ve outlined a few to consider:
Regular calibration ensures that accuracy of the scale is maintained over time. If you need to track calibration, it will be beneficial to have this feature, without the added expense and inconvenience of separate calibration masses. Traditionally, scales are checked for accuracy using a series of certified and traceable calibration masses, and adjusting the mechanism if necessary.
Internal calibration is a feature on newer balances that uses an internal mechanism or circuitry to load the balance with a prescribed weight to check and adjust calibration. Calibration checks and adjustments can be recorded in your quality control documentation.
Sometimes you may need to weigh a sample in suspension beneath the scale. This is particularly common when determining the density and specific gravity of samples. By using a scale with a durable weigh-below hook, you can easily determine density in water or weight samples.
Severely overloading a scale can permanently damage the load cell or weighing mechanism. You may wish to protect your weighing system from overload damage. Scales with this feature provide an electronic limitation. If the limitation is exceeded, the scale will display an error message. Your electronic scale should have overload protection to protect the weighing circuitry.
If you need to use a scale in rugged conditions where water and dirt are present, it’s important to consider models with dust and moisture protection. This allows for a longer service life and some models are even wash-down rated and can be rinsed with a hose.
You may need to use your scale outside of the lab. Take it with you nearly anywhere with rechargeable or replaceable battery power. Sturdy carrying cases are often available or included with certain models.
With this feature, you have the ability to collect weighing data and integrate it directly to your computer. This allows you to generate spreadsheets, process reports, and translate calculations into graphs to showcase findings.
If you need more information about scales, speak to one of our experts by dialing 800.444.1508.