Analytical Balances are one of the most commonly used instruments in quantitative analysis. The accuracy of weighing has a significant impact on the results of the analysis. Therefore, each student must master the correct use of the balance and the necessary routine maintenance to ensure the accuracy of the instrument and the accuracy of the analysis results.
1, weighing rules1. Inspection and correction before weighing
(1) Open the balance cover and check whether the Electronic Balance is in a resting state, whether the position of the beam and the lifting eye is normal, whether the balance is in a horizontal state, and the balance of the balance plate. If there is dust, it can be cleaned with a soft brush.
(2) Check whether the number of special weights and circle codes is complete and the position is normal. Whether the lap reading disk refers to zero. Check the maximum load capacity indicated on the balance and never exceed the maximum load when weighing.
(3) Turn on the power, check and adjust the zero point of the balance. The zero point of the balance often changes, and must be corrected before each weighing. Check whether there is any change in the balance zero when the weighing is completed.
(4) Do not touch the components in the balance box as far as possible. If you need to adjust the balance screws, wear clean gloves.
2. WeighingAfter the zero point correction, close the balance lifting hub, place the object on the scale, and then gently remove the door on the left side of the balance, place the item in the weighing pan, close the left balance door, open the right door of the balance, and The weight of the corresponding weight is placed inside the disc. Slowly open the lifting hub, observe the direction of the pointer swing, judge the weight increase and decrease, close the lifting hub, add and subtract the weight, then open the lifting hub, observe the direction of the pointer swing, and repeat the operation until the balance swings slowly and tends to balance Close the right door of the balance, open the lifting hub, accurately read and record the weight.
3. Calibration and inspection after weighing
(1) Lightly close the lifting hub;
(2) Remove the object and weight and restore the circle code reading disk to zero;
(3) Close the balance door;
(4) Check the zero point;
(5) cut off the power supply;
(6) Cover the balance cover;
(7) Register on the “Use Balance Register”.
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