Two-Pan Analytical Balances Going Vintage

Two-pan analytical balances are a dying breed. The cause is simple: the one-pan analytical balance with modern digital electronics has taken over its function in laboratories and jewelry stores almost everywhere. The reason is equally simple. They are delicate and the process of accurate weighing is time and labor consuming. Good ones can be very accurate, however. They are still used to calibrate test weights. Since their usage is shrinking, so is their availability. Soon enough, they will become collector’s items.

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A Brief History of Analytical Balances

An article by the National Institute of Health (NIH) briefly covers the history of analytical balances in a crisp and succinct manner.  The recorded history of balances goes back to at least 5000 BC, and in fact the very word ‘balance’ arises from the Latin ‘bilanx’ meaning ‘two pans’. The modern two-pan analytical balance was invented by Scottish chemist Joseph Black. The article goes on to describe the basic working of a two-pan balance. For 200 years, from 1750 to 1950, these two-pan balances were the industry and laboratory standard. However, from 1948 onwards, the one-pan balance began to hold sway and is the most common type used today.

Take a look here for a feel of how the modern analytical balance looks and works.

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Buying Tips for Veterinarian Scales

Weighing animals in veterinarian clinics is challenging because few if any of the patients have the patience to remain still on the weighing platform.  Since weight gain or loss is very much a part of the exam, vets and their assistants need all the assistance they can get in securing accurate weight readings. Platform scales such as the Kern EOB, EOE and EOS series available from Tovatech are ideally suited for this requirement because they are designed to compute an accurate stable weight even though the animal does not stand quietly on the weighing plate.

An Animal Weighing System That’s Easy to Use

With only 4 programming keys on the display device these animal weighing scales are a cinch to operate:  on/off, hold, unit (pounds or kilograms) and tare.  It’s the “hold” key that’s key to the animal weighing operation.

With Fido firmly on the easily cleaned stainless steel weighing … Read the rest

How to Choose Platform Scales

A Digital Platform Scale

Precision platform scales are widely used in laboratory, industrial, and related applications where a high degree of weighing accuracy is required.  In addition to weighing mundane items such as packages a platform scale is used for piece counting, net-total recipe weighing, and percentage determination that shows the deviation from a reference weight. 

Platform balances such as the Kern DE series available from Tovatech are available in a variety of models, enabling users to specify the correct scale based on their requirements.   These scales have maximum weighing capacities from 6 kilograms to 300 kilograms (approximately 13 to 660 pounds).  Other models weigh up to 600 kilograms.

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How to use a Counting Scale System for Large Quantities

The KERN CDEE Counting Scale System

When large quantities of small or lightweight pieces are being packaged for market accurate inventory control and accurate billing depend on highly accurate counting scale systems.  In such cases connecting a precision reference scale to a platform scale gives an extremely high degree of weighing and counting accuracy even when individual pieces weigh as little as 0.002 gram.    

That is the precision realized by the Kern CDEE piece counting system available from Tovatech.  It consists of a CDE digital platform balance available in capacities from 35 to 150 kg (77 to 300 pounds) connected by an interface cable to a Kern CME reference balance offered in capacities from 100 to 3000 grams (3.5 oz to 6.6 pounds).  The readout for both models depends on the maximum weighing range but is as low as 1 gram for the platform balance and 0.001 gram for the reference balance.   This versatile combination allows … Read the rest

A Precision Scale is a Versatile Laboratory Tool

Feature-rich digital precision scales can be programmed to perform multiple functions with a high degree of accuracy.

For example, a digital scale does more than simply weigh although “simple” may be the wrong word when speaking of readouts to 0.001 gram and a linearity of ±0.003 gram.  The weighing “precision” of these precision scales is generally inversely proportional to their weighing range (i.e. the higher the maximum accommodated weight the lower the resolution).

Options to Fit Your Applications

Before selecting a precision scale such as the Kern series offered by Tovatech make a list of the features you need to handle your requirements.  As an example, if you work in metric and non-metric units, choose a model that switches to the desired weighing unit at the touch of a button.

Precision scales can also be used for piece counting.  Establish a reference quantity by counting out the required number … Read the rest

When to Choose Internal or External Analytical Balance Calibration

Calibration is a procedure intimately associated with analytical balances.  Calibration determines the relationship between the displayed value and true mass by comparison with a known mass.  In other words, calibration determines the accuracy of an analytical balance or precision scale.

Suppliers of analytical balances and precision scales such as Tovatech have sources that provide calibration services and certificates for newly purchased equipment.  Good laboratory practices, good manufacturing practices as well as conformance to several published regulations call for regular recalibration of these instruments and adjusting them if required.  To accommodate this manufacturers such as Kern offer analytical balances and precision scales with automatic internal calibration and adjustment (if needed) or external calibration and manual adjustment.… Read the rest

Pipette Calibration Made Easy

Poorly calibrated pipettes impact accuracy and reproducibility.  As with precision laboratory scales and balances, periodic recalibration is necessary for testing and adjusting pipettes in accordance with ISO 9001 and GLP directives.

Recalibrating pipettes in-house is made easy with the aptly named EASYCAL™ 4.0 test software on CD-ROM available through Tovatech.  It guides technicians through the PC-based pipette test procedure, carrying out all calculations automatically and comparing them with the tolerance of the current norms or previously defined custom limit values.… Read the rest

How to Use a Precision Scale for Check Weighing

“Net weight one pound” it says on a bag of potato chips.  You used to be able to buy a pound of coffee but now while the cans look the same the weights vary.  One brand notes 11.5 ounces, another 10.3 ounces.  Why is this? More than that, how do we know the can really contains 10.3 ounces of java?  It is a conundrum we have to tolerate.

Joking aside, accuracy in weighing or in counting is no laughing matter when it comes to complying with rules governing net content and average weights.  It is also important from a cost management perspective. While variances in potato chip and coffee weight is not a serious safety concern, putting more in the bag or can than called for is a cost management issue.  Accuracy is a safety issue when it comes to pharmaceutical dosages and similar critical applications.  Here is how precision … Read the rest