How to use a screw blower to dry chemical precipitates. Any object dried or heated, such as weighing bottles, samples, or crucibles, must reach room temperature before being weighed on a balance. However, if left to freeze in the atmosphere, the object will reabsorb moisture and be corroded by dust or other harmful gases; therefore, it must be placed in a desiccant to freeze.
A desiccant is a glass container with a ground glass joint coated with Vaseline and a lid. Inside, there is a ceramic plate to hold the object to be dried, and a desiccant is placed at the bottom to dry the external air. The water content is normally less than 10%. The most commonly used desiccant in experiments is silica gel. Silica gel contains COCl₂ beads; after drying, it is blue, and when it absorbs water to a certain level, it becomes pinkish-white, indicating it has achieved its drying effect. It must be dried completely before use.
The inner wall of the dryer can be wiped clean with a clean cloth or paper. The porous ceramic plate can be washed and dried. The structure of the magnetic levitation blower results in very low mechanical friction loss. Because only the bearings and gear pairs have mechanical contact, the rotor, casing, and gear ring have sufficient mechanical strength in their material selection. Safe operation and long service life are major features of this blower product. Single-stage centrifugal blowers are positive displacement blowers.
During use, the flow rate changes very little with pressure variations. However, the flow rate changes with the rotational speed. Therefore, the pressure selection range is wide, and the flow rate can be selected by choosing the appropriate rotational speed. Apply a very thin layer of [unspecified ingredient] to the ground joint of the dryer. After closing the lid, push or rotate the lid until the oiled area is evenly transparent. When loading the desiccant, be careful to avoid contaminating the oiled ground joint. Do not load too much desiccant to avoid contaminating objects on the ceramic plate.
When moving the dryer, hold the lid firmly with both thumbs. The structure of the screw blower results in very low mechanical friction loss. Because only the bearings and gear pairs have mechanical contact, the rotor, housing, and gear ring have sufficient mechanical strength in their material selection. Safe operation and long service life are major features of the blower products. When closing the dryer, do not lift the lid upwards; instead, use both thumbs to push the lid forward, or hold the bottom of the dryer with one hand. Hold the lid firmly with the other hand and push it forward to open. Hold the removed lid in your hand, or place it on a table with the coated side facing up.
Hot objects should be slightly frozen in the air before being placed in the dryer and the lid closed. When closing the oven lid, do not close it vertically from top to bottom. Instead, hold the bottom of the dryer with one hand and push the lid closed with the other hand, then continue pushing it in, opening and closing it 2-3 times. This prevents the temperature from becoming too high, causing the air inside the dryer to contract and force the lid open, or causing the pressure inside the dryer to increase after freezing, making it impossible to open the lid.