What is the filtration principle of a bag filter

Bag Filter October 17, 2024 Multi Bag Filter Housing

1. Introduction
A bag filter operates under pressure filtration. The entire system includes a filtration vessel, support basket, and filter bag.

Features

High flow capacity
High filtration efficiency
Long filter bag lifespan
Uniform flow distribution ensures even distribution of contaminants across the filter media
High mechanical strength
Simple, convenient operation, safe and economical

Filtration Principle
The liquid to be filtered is introduced from the top of the filter bag, which is supported by the basket. This allows the liquid to distribute evenly across the entire filtration surface, ensuring consistent liquid flow throughout the media without the negative effects of turbulence. The liquid flows from the inside of the filter bag to the outside, trapping particles inside the bag. When replacing the filter bag, there is no risk of contaminating the liquid in the pipeline. The filter bag is designed with handles, allowing for quick and easy replacement.

2. Filter Bag Replacement Procedure

Check the pressure differential between the inlet and outlet pressure gauges, ensuring it is within the range of 0.5 to 1 bar. Prepare to replace the filter bag.
Close the inlet valve and open the compressed air valve to speed up drainage. After 5 minutes, close the outlet valve, shut off the compressed air valve, and release the pressure to open the cover.
Open the top cover of the filter, remove the magnetic rod and the old filter bag, clean the support basket, and place it back.
Insert the new filter bag, ensuring it is positioned flat.
Secure the filter bag with a retaining ring, tightening it clockwise. Use a wrench or other tools to further secure the ring.
Close the top cover, lock the clamp, close the air release valve, open the inlet and outlet valves, and turn on the pump to complete the replacement.

3. Routine Maintenance of the Filter

During regular operation, the filter does not require special maintenance, but attention should be paid to the following:

Regularly check all parts for corrosion or damage.
After replacing a product or when the filter bag is contaminated, a new filter bag should be installed.
Pressure changes (differential pressure between inlet and outlet) will indicate if the filter bag is contaminated. When the pressure difference reaches 1.0 bar, we recommend replacing the filter bag. The maximum allowable pressure difference is 3.5 bar.
Always ensure that the gaskets and sealing surfaces are clean and undamaged. Damaged gaskets must be replaced.

Note: We recommend replacing the gaskets when the pressure vessel is opened. Gaskets are often reused, which can lead to system leaks.