The Different Types of Weighing Processes

Weighing processes can involve a variety of functions from the weighing of ingredients for quality control to measuring finished products. Each weighing process requires precise measurement to achieve its goals.

For mass calibrations the balance, test objects, and reference standards must be in thermal and environmental equilibrium. Careful operation of the balance and use of clean weights will improve accuracy.

Weighing Procedures

Any food production facility, whether a huge plant or small restaurant, needs to use proper weighing procedures in order to produce safe and high quality foods. Weighing is used in all phases of the process from preparing raw materials to final packaging and ensuring that products comply with federal standards.

Several important factors can influence the outcome of a weighing procedure. For example, a balance should be set up in a draft-free location on a solid bench to prevent vibrations. Ideally, the instrument and its weighing pan should also be in thermal equilibrium (e.g., allowing them to come to temperature simultaneously).

When handling fine powders, they can pick up static charge that affects the accuracy of the measurement. For this reason, antistatic devices may be useful. Chemicals that cannot be safely handled in a weighing dish can often be transferred to a preweighed tared piece of glazed paper by squeezing the edges together to form a funnel, and then letting the substance run down the crease.

Analytical Balances

An analytical balance is a key piece of equipment used for precise measurements in labs. These highly sensitive devices need to be kept clean and in good working condition. They should also be periodically calibrated to ensure the accuracy of their results.

The ability of an analytical balance to correctly display a known calibration weight is referred to as its repeatability. It can be tested by putting the same load on the scale, such as a 20-gram calibration weight, and measuring it several times. A reading that is close to the same each time, or within a certain number of divisions, indicates a high degree of repeatability.

Analytical and precision balances are used in many different applications, including differential weighing, formulation, density determination, pipette calibration, parts counting and gross-net-tare weighing. They are essential tools for quality control, manufacturing and research laboratories. They may also be used in pharmacies to weigh medication and medical supplies. They often come with additional features such as a taring function, dynamic weighing and backlighting.

Weighing Dishes

Weighing dishes are safe, contaminant-free, biologically inert economical containers for weighing liquid or powdered samples in the laboratory. They are molded with a smooth surface that facilitates accurate pour-outs and minimizes sample loss. They are not reactive with most substances and will withstand temperatures up to 80oC.

Some weighing systems come with data management capabilities that relay information automatically. This information may be displayed on local indicators, PLC outputs or transmitted to a remote display for monitoring & review. Weighing system experts at Michelli can help you select the right data management system to meet your business requirements.

It is important to avoid touching the weighing pans with bare hands because oils or other contaminants can cause inaccurate readings. It is also important to handle the weights with clean tools to avoid scratching the weighing plates. The aluminum weighing dishes offered by Lab Depot are ideal for general purpose weighing, moisture determination and plasma ashing applications (pre-embedding). These disposable aluminum dishes have tabs or crimped edges and can be used as evaporating dishes, dust covers and as weighing vessels in EM labs.

Paper Weighing

Weighing paper can be a bit confusing, with the many different ways stock is rated and categorized. In North America, two of the most common ratings are points and pounds. A point (also known as pt) is the thickness of the paper measured in 1/1000th of an inch. The higher the number, the thicker the paper.

Pounds, on the other hand, are a measurement of how much 500 sheets of a paper size weigh in its uncut form. This is why you might see a paper rated as 80 lb cover, for example: it weighs about what 500 sheets of that type of paper would weight in its base uncut form before cutting to letter or legal size. Other countries use the metric system method, which specifies that one square meter of the standard sheet size of a paper weighs X grams. This is why you can be more accurate when comparing papers between different countries.

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