Weighing Instructions Mettler Type H Analytical Balances
1. Before Weighing , Be Sure That :
a. The balance is level. If the bubble is not centered within the indicator, turn the leveling disks at the front of the balance until the bubble is centered.
b. The balance is arrested. The arrestment knob should be in normal position.
c. There is nothing on the pan, the pan is clean , and the weighing chamber doors are closed.
d. The weight-control knobs and the micrometer or digital-counter knob are set at zero.
2. Setting The Zero Point
a. Check the zero point of the optical scale with nothing on the pan, the weighing - chamber doors closed , all weight control knobs at zero, and the micrometer or digital - counter knob at zero.
b. Turn the arrestment knob counterclockwise to full-release.
c. When the optical scale stops moving , turn the zero adjustment knob until the zero line of the optical scale is perfectly centered in the indicator slit ( or on models H4 and H15 ) until the zero line of the optical scale is perfectly aligned with the zero line of the vernier scale.
d.Arrest the balance by returning the arrestment knob to position I.
NOTE : All weighings should be made from the zero position . The zero point should be rechecked before each weighing.
3. Loading The Pan
a. Never place the sample to be weighed directly on the pan. Use a container or weighing paper.
b. Arrest the balance and place the sample on the center of the pan with tongs or forceps.
c.Close the weighing - chamber doors.
4. Weighing The Sample
a. Partially release the balance by turning the arrestment knob to normal position. Note that the optical scale lights up.
b. Turn weight control knob A ( lifts weights in multiples of ten ) clockwise until there is a marked upward movement of the optical scale. After the scale moves upward, turn the knob back one position .
c. Repeat this procedure with weight control knob B . If you are working with models H15 or H16, the proceure must be repeated again with weight control knob C . The internal weights are now properly set.
d. Arrest the balance by turning the arrestment knob to position.
e. After a short pause, release the balance fully by turning the arrestment knob to the position.
f. When the optical scale stops moving on models H6 digital, H6T digital, and H16 , turn the micrometer or digital - counter knob counterclockwise until the next lower optical scale graduation is perfectlycentered in the indicator slit or aligned with the pointer.
5. Reading The Result
a. On all models, the number of grams is indicated in the windows on the left of the panel.
b. On models H6 Digital and H6T digital, the first two places to the right of the decimal point are read from the optical scale, the third and fourth decimal places are read from the micrometer opposite the indicator fork.
c. On models H5 and H6 , the first two place to the right of the decimal point are read from the optical scale where the indicator fork perfectly brackets the scale graduation; the third and fourth decimal places are read from the micrometer opposite the indicator fork.
d. On model H4, the first two places to the right of the decimal point are read from the optical scale-read the scale graduation immediately below the zero line of the vernier . The third decimal place is read from the vernier scale-read the scale graduation that is in perfect alignment with an optical scale graduation.
e. Model H15 is read in the same way as model H4 except that the first place to the right of the first place to the right of the decimal point is obtained by turning weight control knob C clockwise . The optical scale and micrometer permit reading to the fifth decimal place.
6. Completing The Weighing
a. Record the result
b. Arrest the balance
c. Remove sample from pan
d. Return all weight control knobs and the micrometer or digital counter knob to zero.
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