Working Process of Ultrapure Water Filtration Equipment Rapid Filter

Filtration

During filtration, open the valves on the inlet branch pipe and the clear water branch pipe. Close the flushing water branch pipe valve and the drain valve. Turbid water enters the filter tank from the turbid water channel through the main inlet pipe and inlet branch pipes. After passing through the filter media layer and support layer, it flows through the distribution branch pipes of the distribution system and then through the main distribution system channel and clear water branch pipes to the clear water tank. As the turbid water flows through the filter media layer, impurities in the water are trapped. As the amount of impurities trapped in the filter layer gradually increases, the head loss in the filter media layer also increases accordingly. Generally, when the head loss increases to a certain extent, causing a decrease in the filter tank's water production, or when the filtered water quality does not meet the requirements, the filter tank needs to be stopped for flushing.

Flushing

During flushing, close the valves on the inlet branch pipe and the clear water branch pipe. Open the drain valve and the flushing water branch pipe valve. The flushing water originates from the main flushing water pipe and branch pipes, flows through the main and branch pipes of the water distribution system, and exits through numerous perforations on the branch pipes. It passes from bottom to top through the support layer and filter media layer, distributing evenly across the entire filter bed surface. The filter media layer remains suspended due to this even distribution from bottom to top, thus being cleaned. The flushing wastewater flows into the flushing drainage trough, then through the turbid water channel, drain pipe, and wastewater channel into the sewer system. Flushing continues until the filter media is essentially clean. After flushing, filtration restarts. The time from the start of filtration to the end of flushing is called the rapid sand filter's working cycle. The time from the start of filtration to the end of filtration is called the filtration cycle.

The water production rate of the rapid sand filter determines the filtration rate (in m/h). The filtration rate is equivalent to the filter bed load, which is measured in m³ (m²·h) of filtered water per unit time and unit filtration area. According to design specifications, the filtration rate of a single-layer sand filter is approximately 8-10 m/h, while that of a double-layer filter media filter is approximately 10-14 m/h. Multi-layer filter media filters typically achieve a filtration rate of 18-20 m/h. The working cycle also directly affects the filter's water production. The length of the working cycle affects the actual operating time of the filter and the amount of backwash water consumed. A shorter cycle reduces the daily water production of the filter. A typical working cycle is 12-24 m/h. With increasing environmental awareness and the needs of industrial development, rapid sand filters will play an increasingly important role in modern ultrapure water extraction!