How to Select a Digital Bench Scale

A bench scale is generally placed on – you guessed it – a bench or a countertop.  A distinguishing characteristic of digital bench scales vs. platform scales is that the controls and display are part of the unit whereas a platform scale display is separate from the weighing platform.

Kern bench scales available from Tovatech have weighing ranges from 6 to 60 kg allowing them to support a broad range of applications.  Most are available with standard disposable battery power or optional rechargeable battery power in addition to line power.  This is a big plus if you need portability or perform weighing operations beyond the reach of an outlet.

Specifying Digital Bench Scales

This is a straightforward process until it comes to added bells and whistles you may require for your operations.  First the basics:

At the top of your list is the maximum weight the scale can handle.   If … Read the rest

Blood Typing

Many years ago I had to take an employer-required class in project management. Having already worked as a project manager with good results, I was prepared to be bored, but I tried to have a good attitude. Luckily, my mind was cracked open enough to accept some input, because (even though I felt I could have taught the class) I learned a lot from hearing another perspective. Since then, I’ve tried to stay receptive, even when I think I know something, and I’ve nearly always added to my knowledge, like I did watching this video outlining blood types. The simple explanation will let you know why not every unit of blood in the blood bank refrigerator will be a good transfusion candidate for you.… Read the rest

IP65-Rated Platform Scales Solve Multiple Weighing Tasks

Platform scales are workhorses of weighing, often finding themselves in environments that cause less rugged weighing systems to fail.   The new Kern SFE platform scales, now available from Tovatech, build on the ruggedness and reliability of platform scale weighing systems.  Their silicon-coated load cells and separate free-standing or wall mounted stainless steel control panel/display units are packaged in IP65-rated housings.  This means these high-precision but rugged platform balances are totally protected against dust.  When exterior surfaces need cleaning they resist low-pressure jets of water.*

Three Models with Readouts of <1 oz

SFE platform scales provide maximum weighing to 15, 30 and 60 kg (33, 66 and 132 pounds).  Respective readouts are 5, 10 and 20 grams (all less than one ounce).   Easy-to-follow instructions allow operators to use the control panel to perform a variety of weighing tasks including recipe, tolerance, and animal/dynamic.   Tolerance (check weighing) to an upper/lower value is … Read the rest

Selecting an Entry-Level Single Cell Analytical Balance

An analytical balance is one of the more precise weighing and measuring tools available to industrial and academic research organizations.  Laboratory balances equipped with single cell weighing systems have traditionally represented the high end of these precision weighing systems but at a cost premium.  Technology advances have changed that, as evidenced by the new Kern ABS/ABJ series of analytical balances available from Tovatech.

What is Single Cell Weighing?

Simply stated, these systems use a single block of material such as aluminum as the weighing mechanism as opposed to multiple-component conventional balances.  Because they have no moving parts there is no wear and tear.  As a result these balances continue to perform well for a longer time than scales with conventional weighing mechanisms.

Other important advantaged include improvements in accuracy, precision, speed and reproducibility of weight values due in no small part to higher corner load reliability.  The latter means that … Read the rest

How to Judge Scale Accuracy

At Tovatech we frequently find that customers are confused about weighing terms associated with analytical scales and precision balances, especially as it relates to scale accuracy.   This comes as no surprise to us because, in fact, the terminology is confusing.   Different manufacturers of analytical balances will use different weighing terms, some of them incorrect, by the way, to describe the performance and accuracy of their products.  When you evaluate electronic scales you should compare the performance of a specific manufacturer’s products against each other rather than with those of different manufacturers.

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How to Achieve Precision Weighing with an Analytical Balance

An analytical balance is a precision instrument requiring much more care and attention than industrial scales and balances used outside academic and industrial research and QC labs.  Analytical balances also represent a substantial investment with prices depending on weighing range, readout, reproducibility and linearity.  For these and other reasons lab personnel should understand how and how not to use these instruments, thereby maintaining equipment accuracy and extending equipment life.  Here are some basic steps to follow.  The balance operations manual, however, is the authority in all cases.

Setting Up an Analytical Balance

As Maria sings in “The Sound of Music” let’s start at the very beginning.  Setup instructions for Kern analytical balances offered by Tovatech stress the importance of location, which ideally will be permanent.

Before unpacking the precision scale select a firm level surface remote from extreme heat, temperature fluctuations, direct sunlight, drafts, high humidity, vapors, dust and vibration.  … Read the rest

Analytical Balance Mistake Made Even By Doctoral Students

The narrator in this video has a pet peeve. A mistake that he has seen repeated time and again by not just undergraduate students. Postgraduate and doctoral candidates too make this mistake when working with an analytical balance. In the first part of the video he explains the general functioning of the analytical balance and the steps you need to take to get accurate and consistent results. In relative terms what is important is consistency. Should the analytical balance reading be wrong, if the error is consistent – due to a faulty calibration or some such issue then the results are usable to some degree. However if the readings are inconsistent and vary widely for the same type of weighing object or process then the results are both inconsistent and unusable. As for that pet peeve? Watch the video to find out!… Read the rest

Measuring Mass with The Analytical Balance

Here is another video that explains the use of an analytical balance. In this video the instructor explains several key elements that are critical to making accurate measurements with the analytical balance. This includes making sure the balance pan is free of all debris and spills and measuring the object at room temperature. Objects that are above or below room temperature result in pressure changes leading to inaccurate results. While the video shows how to calculate the mass of the substance by noting the difference in mass with and without the substance on the measurement vessel, you can also obtain the mass of the substance directly by taring the empty measurement vessel.… Read the rest

Difference Between Top Loading and Analytical Balance

If you’ve ever wondered about the difference between a precision scale and an analytical balance then this experiment will be instructive.  The document explains the difference between mass and weight and the functioning of the top loading precision scale and the analytical balance.  It then goes on to discuss precision, accuracy, significant figures, and error analysis (linked elsewhere), and finally, it explains the experiment that will be used to demonstrate the workings of both these balances.  As with instructions on using an analytical balance in other places on our blog, this document too highlights the critical aspect of working with these sensitive measuring devices.

For further information visit… Read the rest

Hygroscopic Material and Fingerprints When Using An Analytical Balance

Here’s another instruction sheet on the proper use of an analytical balance.  As with other similar how-to’s that we’ve covered this one is also similar.  Avoid vibrations and drafts, do not touch the objects being weighed, allow hot objects to cool before weighing, and other similar tips. A couple though need to be called out for special attention.  Avoid smudging the objects being weighted as even fingerprints will have an impact on the mass.  At 0.1 mg precision fingerprints and even air can change the result.  The second tip is similar.  Measuring the mass of hygroscopic materials.  Do this fast as the material will be absorbing atmospheric water vapor even as the weighing progresses.

For further information visit… Read the rest