Weighing is a crucial part of the production process. It ensures that ingredients meet quality requirements and that the final product tastes the same in every batch.
Level or inventory weighing applications involve determining how full a storage vessel is. These applications must ignore plant and process mechanical noise and have enough resolution to indicate time-critical weight cutoffs.
Weighing by weight
Weighing by weight is a common method used to measure objects and products. It is based on a spring scale that either stretches (like the hanging scale in your grocery store) or compresses (as in a simple bathroom scale). The force of gravity exerted by the object is proportional to the amount of compression or stretch caused by the spring, and this is translated into a dial reading on a display unit.
Weighing by Difference excels in precision and contamination control, making it the best choice for pharmaceutical and manufacturing applications where high accuracy is vital. However, if speed and convenience are more important, Direct Weighing is a more practical solution. This method reduces the need for additional steps, such as taring containers, and eliminates scale calibration errors. It is also more cost-efficient when compared to other weighing methods. In the food and beverage industry, this method is often used for measuring ingredients in bulk.
Weighing by volume
Unlike weight, which is measured in gallons or pounds, volume is a measure of space an object occupies. It can be calculated by multiplying an object’s length, width and height, or by using a volume calculator.
In baking, it’s important to know how to weigh ingredients by volume so that your recipes turn out correctly. This will help you avoid over- or under-mixing your batter, which can cause a cake to collapse or not rise properly. You can also use the tare button on your scale to zero out any bowls or cups you’re using, so that the weight of the container doesn’t count towards the total measurement.
Understanding the difference between volume and weight is essential for ensuring your clothes are washed properly, your pool or hot tub is filled with water accurately, or that you have enough storage space. This is because finding the density of an object requires knowing its volume, which in turn depends on its mass and acceleration of gravity.
Weighing by mass
Mass is the amount of matter an object has, and weight is the gravitational force exerted on that matter. The terms are sometimes used interchangeably, but they have very different meanings. For example, an elephant has more mass than a ping-pong ball, but the latter may have more g-force because it is smaller.
It is important to know how to weigh by mass properly in order to get accurate results. This involves ensuring that the weighing instrument is clean and free of debris. It also requires a container that will not chemically react with the sample being measured. For larger samples, a balance-type weighing scale is typically used. This consists of a pivoted horizontal lever with arms of equal length and a weighing pan suspended from each arm.
A tare button or function is usually labeled on the balance. This will reset the readings to zero, making sure that the instrument is starting with a clean slate. This is especially important for instruments that will be used in a humid environment or with hygroscopic samples.
Weighing by difference
When working with precise materials, such as pharmaceutical drugs and reagents, accuracy is crucial. But even the smallest error can have drastic consequences. This is why weighing by difference is one of the most accurate weighing methods available. It eliminates the need for a container, which can introduce errors by itself, and ensures that any errors are canceled when subtraction is performed.
To use this method, a piece of weighing paper is placed on the balance pan and the balance is set to read 0.000 g by taring it (using the tare button). Then the sample container is added (see the image below), and the difference in mass between the two readings gives the weight of the substance being transferred.