15 Questions about Laboratory Analytical Balance(Part 1)

2020/10/27

Question 1. Does the laboratory have to establish a special balance room to place one-thousandth of the balance? Can it be directly placed on a separate sky platform in the testing room?

The environmental condition requirements of this level of balance are generally that the temperature is not more than 30 degrees Celsius, the humidity is not more than 85%, and the temperature difference during operation does not exceed 5 degrees Celsius; but whether it can be directly placed in a separate overhead platform in the testing room should also consider whether the room is There are corrosive gas, vibration and air flow, etc., if all are satisfied, it can be released.

Question 2: Should the silica gel in the laboratory balance be replaced regularly, and how often should it be replaced?

Experts suggested not to put desiccant in the balance, but to control the temperature and humidity in the balance. If you really want to put it, it is based on the actual situation, and half of the color will change.

Question 3: How to do internal school of electronic balance?

1. The balance should be warmed up for approximately 2-3 hours.

2. The balance should be horizontal, otherwise it must be adjusted.

3. When there is no item to be weighed on the balance scale, it should be stably displayed as zero.

4. Press the "CAL" key to start the internal calibration function of the balance. After a while, the electronic balance displays "C", indicating that the internal calibration is in progress.

5. When the electronic balance display shows zero position, it means that the electronic balance should have been calibrated.

Question 4. How to do external school for electronic balance?

1. The balance should be warmed up for more than 30 minutes.

2. The balance should be level.

3. When there is no weighing item on the balance scale, it should display the zero position stably.

4. Press the "CAL" key to start the calibration function of the balance.

5. The weight value of the external adjustment weight is displayed on the display of the balance.

6. Put the standard weight that meets the accuracy requirements on the weighing pan of the balance.

7. When the display value of the electronic balance does not change, it indicates that the external calibration work has been completed and the standard weight can be taken out.

8. The balance shows that the zero position is in a standby state.

If there is an error in the calibration, the electronic balance display will display "Err", the display time is very short, it should be reset to zero and re-calibrate.

Electronic Balance

Electronic Balance

Question 5. What are the balances of different accuracy levels used for?

1. The accuracy is lower, and the process preparation test is done.

2. One-thousandth, do process test.

3. One in ten thousand, do the above test and chemical analysis test.

4. One-hundred-thousandths, for instrumental analysis.

5. Higher accuracy, one part per million, used for instrument analysis (our department does not have).

Question 6. How much does the weighing paper affect the balance?

1. If the weighed sample is too small, it may be affected by buoyancy and static electricity during weighing, which may cause unstable weighing results.

2. The outer edge of the weighing paper exceeds the range of the weighing pan, causing the weighing center of gravity to shift.

3. The weighing paper is in contact with other parts of the weighing pan, causing inaccurate weighing results.

Question 7. In order to control the temperature and humidity, it is inevitable to turn on the air conditioner or fan in summer. How to avoid the influence of wind on the balance?

1. The balance should be placed in the laboratory away from doors and windows;

2. When there are multiple balances, the more precise the balance should be placed inside;

3. It is best to install a glass windproof door for the analytical balance. The extremely high-precision micro/ultra-micro balance even needs two layers of windproof doors.

Question 8. Is the last digit of the balance a suspicious number?

In general, the last digit is the inaccurate value of the display division value d, and the penultimate digit is the actual division value e, which is an accurate value. But there are exceptions. For some balances, e=d, at this time the last digit is the exact value.

Question 9. Why can't we directly weigh the needed medicines with a beaker when the range of the balance is not exceeded?

The balance is a precision instrument, and the mass of the beaker is generally large. Even in the weighing range, the impact on the balance is still more serious than the weighing paper. The impact on the balance is also great! Therefore, it is generally not recommended to use a beaker for direct weighing, but it is not unusable!