When does the filter bag need to be replaced?

The working principle of liquid filter bag filter is pressure filtration. The container is divided into upper and lower cavities by filter media to form a simple filter. The suspension is added into the upper chamber and enters the lower chamber through the filter medium under the pressure to become the filtrate. The solid particles are retained on the surface of the filter medium to form the filter residue. During the filtration process, the filter residue layer on the surface of the filter medium is gradually thickened, the resistance of liquid passing through the filter residue layer is increased, and the filtration speed is reduced. When the filter chamber is full of filter residue or the filtration speed is too low, stop filtration, remove the filter residue, and regenerate the filter medium to complete a filtration cycle. In order to continuously meet the market requirements, the manufacturer will further improve the equipment and improve the range of filtration and separation; Intercept some substances other than solids, etc.

When to replace the filter bag?

Two ways to determine when to replace the filter bag

1) Roughly determine the replacement time based on experience.

2) Pressure gauges are installed on the inlet and outlet pipes of the bag filter. The time to replace the filter bag is determined by the pressure difference displayed by the front and rear pressure gauges. Generally, the pressure difference that the filter bag can withstand is about 0.5~1kg/cm2. When the pressure difference reaches this range, the filter bag should be replaced in time to avoid the filter bag rupture, which will affect the filtering effect. Do not lose weight for small things.

2. Progressive filtration: The bag filter can be installed in series to achieve progressive filtration. If it is installed at the front end of the filter used for high-precision filtration, the filtration cost can be greatly reduced. Also, sand filtration and other filtration methods can be combined with bag filtration to further improve the filtration quality and reduce the consumption cost of filter bags. By combining self-cleaning machine, centrifugal filter and bag filter, we can use them alone or in series with other filter principles to achieve appropriate results.

3. How to achieve uninterrupted filtering? The parallel installation of bag filter can ensure the continuity of filtration, or increase the flow, install in parallel and replace the filter bags alternately to maintain the continuity of filtration.

Selection of bag material and performance of multi-bag filter

1. High-temperature resistance of filter bag. Many large industrial sewage has a relatively high temperature when it is discharged. At this time, it is necessary for filter bag to have high-temperature resistance.

2. Fold-resistant and abrasion-resistant, the product sewage will contain a lot of plastic, PE bag metal substances, etc. These substances will flow into the multi-bag filter tank under the pressure of the pump, which will impact the filter bag. Therefore, the filter bag is required to be resistant to bending and friction.

3. Oxidation-resistant. Many factories in China are still using coal-fired boilers to heat industrial water, and the content of nitrogen oxides in sewage is high. If it is necessary to filter the water for filtration, it is necessary to select the water with good oxidation resistance.