English
The cleanliness and humidity control of the laboratory have a great impact on the laboratory calibration weights, especially in the process of high-precision measurement and calibration. These factors may directly affect the accuracy, stability and long-term service life of the weights. The following are the specific effects of these two factors on calibration weights:
The impact of cleanliness on laboratory calibration weights is reflected in the following aspects
If dust, oil or other impurities accumulate on the surface of the calibration weight, it will affect the accuracy of its mass. Surface contaminants may cause a slight increase in the weight of the weight, especially on high-precision weights, even a small amount of contamination may affect the measurement results.
Fine dust and particles attached to the surface of the weight will increase the surface quality of the weight, change the weight of the weight, and cause measurement errors. This is especially important in a precision calibration environment. Dust may affect the contact between the weight and the weighing instrument, resulting in inaccurate readings.
Some oils, chemicals or fingerprints on the hands may also adhere to the surface of the weight, which will not only change the quality of the weight, but also corrode the metal material of the weight (such as stainless steel, cast iron, etc.), affecting the long-term stability of the weight.
High-precision weights are usually very sensitive to external factors. Static electricity, airflow, impurities in the air, etc. may affect their surface. For example, static electricity can attract dust and particles in the air, causing fine impurities to adhere to the surface of the weight.
If anti-static measures are not taken in the laboratory, static electricity may absorb tiny particles in the air, causing impurities to adhere to the surface of the weight, thus affecting its accuracy.
Especially in industrial environments or laboratories with pollution sources, pollutants in the air may also be deposited on the surface of the weight, thereby affecting the calibration results.
Some high-precision laboratories, especially national metrology laboratories, usually have strict cleaning requirements. For example, the control of cleanliness levels, the use of air filtration systems, the wearing of dust-free clothing and gloves, etc., to reduce pollution sources.
Humidity is another crucial factor in the laboratory environment because it directly affects the physical properties of materials, especially metal calibration weights. Too high or too low humidity may cause the mass of the calibration weight to change, affecting its accuracy.
Most calibration weights are made of metal materials, such as stainless steel, cast iron or alloys. These metals absorb moisture when the humidity is high, resulting in slight changes in volume, which in turn affects their quality.
High humidity can cause moisture to adsorb on some metal surfaces, especially weights that have not been properly surface treated. The adsorption of moisture can cause a slight expansion of the weight or oxidation of the metal surface, which can change the weight's mass and shape.
If the humidity is too low, the metal surface may become too dry, causing microcracks or wear on the weight surface, which can affect its accuracy in long-term use.
Excessive humidity can also accelerate corrosion and oxidation of metals, especially for weights that have not been specially surface treated. For example, iron weights tend to rust in a humid environment, and stainless steel weights may also gradually oxidize in a humid environment.
If the metal surface is corroded, it will not only make the surface of the weight uneven, but also increase the mass, which will affect the accuracy of the calibration.
For example, stainless steel may oxidize and discolor in a high humidity environment, and produce an irregular oxide layer on the surface, which may have a slight effect on the mass of the weight.
In general, the laboratory needs to maintain a suitable humidity range (e.g. 30%-50%) to prevent the influence of humidity on the weight. Precision calibration laboratories are equipped with humidity control systems to ensure stable humidity in the environment, thereby ensuring the long-term accuracy of the weights.
Deep cleaning should be performed regularly in the laboratory to keep the workbench, instruments and calibration weights clean and free of dust or oil.
Use special cleaning tools and methods (such as ultrasonic cleaning) to clean the surface of the weights, and avoid using any chemical cleaning agents that may damage the surface texture of the weights.
Operators should wear dust-free clothing and gloves to reduce contamination caused by human activities.
Install an efficient humidity control system and use a dehumidifier or air conditioning system to ensure constant humidity in the laboratory.
Check and calibrate the hygrometer regularly to ensure that the humidity level meets the requirements.
Use a drying box or sealed cabinet where the weights are stored to avoid the influence of moisture from the external environment.
The cleanliness and humidity control of the laboratory directly affect the accuracy and stability of the laboratory calibration weights. In terms of cleanliness, fine contaminants may cause weight deviation of the weights, which in turn affects the calibration results. In terms of humidity control, high humidity can cause expansion and oxidation of metal materials, thereby changing the quality and shape of the weights. Therefore, ensuring a clean laboratory environment with proper humidity control is essential to ensure the accuracy and long-term stability of calibration weights.
