Views: 291 Author: Site Editor Publish Time: 2020-11-14 Origin: Site
The lab weight balance is a vital and indispensable basic equipment for any laboratory. In the first place, we should have a clear idea of use and application of a laboratory weighing balance when we decide to buy it.
There keep three factors that will affect the choice of lab weighing balance: the purpose of balance, the type of materials, and quantity of materials. For solid inert materials of one kilogram and above, it pays to choose a lab industrial balance. With intent to measure medicinal compounds at the microgram level, we need to give top priority to an accurate analytical balance.
By the same token, please consider the balance laboratory and the overall environment. For dusty environments (such as factory floors), weighing balances for lab that are sealed to prevent damage from external materials have more advantages. If there remain draught, vibration, or temperature fluctuations, a sensitive analytical balance may not work well. Some balances keep with their casing to prevent the entry of contaminants.
If the work in progress requires certification, or involves toxic or radioactive materials, it may need to meet regulatory and personnel training requirements. Besides, the frequency of use will affect the choice. The balance used every day needs to be intensely durable and reliable.
According to Mettler Toledo, the manufacturer of lab analytical balances, customers often underestimate the level of accuracy of the weighing balance required by their processes. After the application is clarified, the desired target in terms of accuracy can be determined in accordance with relevant international norms and guidelines.
A company spokesperson said that high readability does not necessarily equate to high accuracy. For example, a customer can choose a laboratory precision balance with a readability of 0.1 mg (4 decimal places). The accuracy of the balance is related to the measurement uncertainty of each reading. Fast and stable weighing results do not necessarily indicate accuracy. An incorrect laboratory digital weighing electronic balance will contribute to incredulously produce repeatable results.
Admittedly, choose different types of balances according to the functions that the balance must perform. Types of laboratory balances include the highest load balances, portable balances, analytical balances, semi-micro balances, and microbalances. There are some overlaps in readability and accuracy. In this case, the user's application and the weighing environment will usually determine the type of balance required.
Likewise, the balance can also be defined according to their weighing sensor. Some balances use strain gauges, which is essentially a metal object that deforms with the applied strain, giving rise to a change in resistance that may be related to the strain caused by weight. Strain gauges are often found in shop scales and other large instruments.
In the higher accuracy range, a sensor based on electromagnetic force compensation can be used. In this type of sensor, the weight applied to the scale is compensated by an electromagnetic force. Vertical position changes in the coil will trigger the current to return the position to zero. Because the current is proportional to the weight, the weight value can be calculated from the current.
A spokesperson at Mettler Toledo said: “Although it is invisible, the load cell is the heart of every balance and is the main factor affecting its accuracy and price.” The load cell should provide a fast and repeatable weighing ability, stable to thermal fluctuations, and should be reasonably maintained.