The automatic backwashing filter is widely used in industrial and municipal wastewater treatment, industrial production, drinking water treatment, and other scenarios. Its main function is to remove dirt and sediment on the surface of the filtering medium through the backwashing process, maintaining the efficient filtering performance of the filtering medium. The backwashing triggering mechanism and working principle of the automatic backwashing filter are the key to ensuring its long-term and efficient operation. Below, we will introduce this process in detail.

Working principle of the automatic backwashing filter

The working principle of the automatic backwashing filter mainly includes two stages: the filtering stage and the backwashing stage. During the filtering stage, the fluid is filtered through the filtering medium (such as filter mesh, filter sand, etc.) to remove particles, suspended matter, and other impurities. In the backwashing stage, the filter clears the dirt and sediment on the surface of the filtering medium through a specific backwashing program, restoring the filtering performance of the filtering medium.

Backwashing triggering mechanism

The backwashing triggering mechanism of the automatic backwashing filter is mainly based on two conditions: filter material resistance and filter differential pressure. When the filter material resistance or filter differential pressure reaches the preset threshold, the filter will trigger the backwashing program.

Filter material resistance triggering mechanism: During the filtering process, dirt and sediment gradually accumulate on the surface of the filter material, causing an increase in filter material resistance. When the filter material resistance exceeds the preset value, the filter will automatically start the backwashing program to remove the dirt and sediment on the surface of the filter material and restore the filtering efficiency of the filter material.

Filter differential pressure triggering mechanism: Filter differential pressure refers to the pressure difference between the inlet and outlet of the filter. During the filtering process, as the dirt accumulates on the surface of the filter material, the filter differential pressure gradually increases. When the filter differential pressure reaches the preset value, the filter will also automatically trigger the backwashing program to restore the filtering performance of the filter.

Backwashing process

The backwashing process usually includes the following steps:

Backwashing start: When the triggering conditions are met, the filter begins the backwashing process. At the start of backwashing, the backwashing valve is opened to allow backwashing water to enter from the filter's inlet, pass through the filter material layer, and wash away the dirt and sediment on the surface of the filter material.

Backwashing water flow: The backwashing water flows through the filter material layer, carrying away dirt and sediment into the outlet of the filter, and is discharged through the filter's sludge removal system.

Backwashing completion: After the backwashing is completed, the backwashing valve is closed, and the filter returns to the filtering state. Subsequently, the filter may undergo a period of pre-filtration or additional backwashing to ensure the cleanliness of the filtering medium.

Conclusion

The automatic backwashing filter achieves automatic maintenance of the filtering medium through the triggering mechanism of filter material resistance and filter differential pressure, ensuring the long-term and efficient operation of the filter. This mechanism not only improves the service life of the filter but also reduces the frequency and cost of manual maintenance, which is of great significance for ensuring industrial production and environmental protection.