Operating Your Balance
Once you have found the proper location, unpacked and setup your new balance you will need to learn how to properly operate the unit.
Remember from the previous blog that the balance should be placed in a location that is:
- Out of direct sunlight and lighting
- In a location with reduced vibrations
- An area with limited drafts caused by doors or overhead AC units
- A room with constant temperature and humidity between 45-60%
The first step to ensure that the balance weighs accurately is leveling. Leveling will deliver reliable results. Usually each balance or scale will come equipped with a leveling bubble that tells you if the unit needs leveling. You want to rotate the feet to guide the bubble to the center. Each time the scale is used check to make sure the bubble is still centered and any time the unit is moved re-leveling will most likely need to occur. It is critical that the final position be parallel to the direction of acceleration and perpendicular to the weighing system. Many times the scale or balance will be out of tolerance if the unit is not leveled so this is of high importance.
After leveling, the balance or scale’s calibration needs to be checked and possibly adjusted. Calibration intervals should be determined based on the frequency of use. It is a general rule of thumb than any balance or scale should be calibrated once a year regardless of use. Remember that recalibration is needed if the ambient conditions (temperature, humidity, or air pressure) change.
Once leveling and calibration are done, it is important to select the right container for your sample. You always want to use the smallest possible sample container and it is recommended that glass be used instead of plastic. Plastic materials tend to cause static electricity which might affect your readings. You never want to touch samples or the container with bare fingers due to possible transfer or loss of particles. Make sure the sample and container acclimate to the environment before weighing. If the sample is to warm then the value displayed will be lower than what it actually is and the same applies to samples that are colder than room temperature.
After you determine what sample you are weighing and the container that is being use, it is important to place the item in the center of the weigh pan. If it is not close to the center, you may experience eccentric loading and the weight readout might be skewed.
It is important to use the same weighing procedure to ensure accurate and repeatable results. Make sure to always close the draft shield before reading the results and if it is a toploader allow enough time for the unit to fully stabilize. Always zero the balance/scale if needed and make sure to “tare” the sample container.
Finally, make sure that the balance/scale is cared for when you are done using it. You want to make sure the weighing pan and chamber are clean at all times. Use a fine brush or cloth to remove spilled samples. Cleanliness of the chamber will reduce disturbances.
To review the steps of proper balance operation:
- Always check to make sure the unit is leveled
- Check that calibration is current and perform adjustment if needed
- Pick an appropriate container for your sample and never touch the sample or container with bare hands
- Center the sample in the weigh pan
- Use the same weighing procedure to maintain repeatable results
- Make sure balance is properly cleaned at end of use