Ultrapure Water Equipment Coagulant Preparation and Dosing Process 1

Coagulants in water purification plants generally adopt wet dosing, including agent dissolution, preparation, metering, dosing and mixing.

The dosage of pharmaceuticals can be done by gravity or by pressure. Generally, pressure is used more frequently.

The gravity dosing system needs to set up a high-level pool to use gravity to put the liquid into the raw water. The height difference between the high-level pool and the dosing point should be sufficient to overcome the head loss of the pipeline transporting the chemical liquid and leave a certain margin. Gravity dosing is suitable for small and medium-sized water plants where the dosing points are concentrated and the back pressure is consistent. The gravity dosing rotating tube should not be too long and should be straight to avoid blockage and air blockage.

Pressure dosing can use two methods: water ejector and dosing pump. The use of water ejector for dosing has the advantages of simple equipment, easy use, and is not limited by the height of the chemical pool. However, the efficiency is low and an additional water ejector pressure water system needs to be set up. The back pressure at the dosing point cannot be greater than 0.1MPa.

Dosing pump dosing usually uses a metering pump. The metering pump has both pressure conveying and metering functions. In conjunction with automatic dosing control equipment and water quality monitoring instruments, it can form a fully automatic dosing system to achieve the purpose of automatically adjusting the dosage of dosing. Currently commonly used metering pumps include diaphragm pumps and plunger pumps. The use of metering pumps for back-to-work filling has the advantages of high metering accuracy, adjustable filling volume, and is not limited by back pressure at the dosing point. It is suitable for water plants of various sizes and various occasions, but the price of metering pumps is relatively high. At present, most of the newly built and renovated water plants use metering pump dosing.