Measurement and precautions of ash density on the surface of insulator

1. Definition of ash density: the total mass of insoluble matter in the dirt on the insulator surface divided by the surface area. The unit is mg / cm2.

2. Measurement steps of gray density: (Take HM-3000 gray density tester as an example)

(A) Dissolve. Dissolve the dirt on the surface of the insulator in a certain volume of distilled water. The volume of distilled water is approximately the surface area of ​​the insulator (in cm2) * 0.2ml. Example: The surface of the insulator is 1450 cm2, then the volume of distilled water should be about 290ml. When the amount of salt in the pollutants is large, the amount of water can be increased as appropriate.

(B) Filter. There are two methods of filtration, one is conventional filtration, and the other is filtration using a vacuum suction filter device. Conventional filtration experiment conditions are simple and easy to operate, but the filtration speed is slow. The advantage of using a vacuum suction filtration device is that the filtration speed is fast, but the price of laboratory equipment is higher.

(C) Dry. Fold the filtered filter paper at 90 degrees and put it into a constant temperature drying box to dry it. When the drying temperature is set to 90 ° C, it may be dried for 30 minutes. Specifically, it should be completely dry.

(D) Weighing. Weigh the weight of the filter paper before filtration and count it as Mf; weigh the dried filter paper with dust together and count it as Ms.

(E) Calculation. The ash density on the surface of the insulator is NSDD = (Ms-Mf) / S. The unit is mg / cm2.

3. Matters needing attention in the measurement process

(A) It is recommended to use special gauze to wipe the dirt of the insulator, and test paper can also be used instead. The basic requirement is that the wipes and filter paper used for wiping do not contain soluble substances. Otherwise, the measurement result will be too small.

(B) When using the balance, first adjust the balance base to a horizontal position. Do not touch the balance weight and the tray directly with your hands.

(C) The temperature during drying cannot be set too high, generally not exceeding 110 ° C, otherwise it may cause the filter paper to burn.