Firstly, it is necessary to understand the filtration mechanism of the bag filter system: liquid flows from the inside of the filter bag to the outside, and the filtered particles are trapped inside the bag. The working principle of bag filter is pressure filtration. The bag filter system mainly consists of three parts: filter container, support net basket, and filter bag.

1. Selection of filter bag material:

Firstly, based on the chemical name of the fluid to be filtered and the chemical compatibility taboos, identify the available filter media. Then, evaluate the filter media temperature, operating pressure, pH value, viscosity (CPS), impurity type (such as hard or soft particles), impurity content (PPM), and operating conditions (such as whether it is necessary to withstand steam, hot water, or chemical sterilization) one by one, and remove unsuitable filter materials. Usage is also an important consideration, for example, filter materials used in drugs, food, or cosmetics must be FDA approved materials; For Ultrapure water, the filter material that is pure and does not contain any release will affect the specific impedance must be selected; For gas filtration, hydrophobic materials must be selected and whether a "sanitary grade filtration" design is required.

2. Precision selection of filter bags:

This is a troubling issue. For example, to remove visible particles, a 20 or 25 micron filter bag should be used; To remove cloud like substances from the liquid, a 1 or 5 micron filter bag should be used; To filter out small bacteria, a 0.2 micron filter bag is required. The problem is that there are two filtering accuracy units: precision/nominal precision.