First, remove contaminants from the measuring device mechanically, such as brushing with a hair brush, or shaking with water (if necessary, add filter paper pieces). The oil or oil can be removed with a suitable solvent, then injected into the low-foam washing liquid and shaken vigorously. Rinse with tap water until the wash liquid is completely rinsed off, and then wash with water three times.
Second, if the inner wall is still not clean after the method is processed, use the following lotion to wash:
1. Mixture of saturated potassium dichromate and concentrated sulfuric acid. Note: The chromic acid lotion is toxic. If you can use other methods to clean the meter, do not use chromic acid lotion. Wear protective mask and gloves when preparing potassium dichromate and sulfuric acid mixture.
2. An equal amount of 30 g/L potassium permanganate (KMnO,) solution and 1 mol/L sodium hydroxide (NaOH) mixed solution (the mixture will have residual manganese dioxide, dilute hydrochloric acid or Oxalic acid removed].
If necessary, you can use the above lotion to soak a few decimal places. Then rinse it several times with distilled water and check if it is clean. If it has not been cleaned, it can be cleaned repeatedly.
Third, if the container after cleaning is not used immediately, it should be stored in distilled water.
Although the softening point of the glass used to make the gauge is around 500°C, it is recommended that the glass gauge drying temperature should not exceed 150°C because the heating temperature, although lower than the softening point, also causes a change in volume.