In the industrial solid-liquid separation scenario, filter cloths are common consumables, and their core performance is often determined by the pore size parameters. 

The pore size of the filter cloth refers to the size of the channels formed by the fibers on the surface of the filter cloth. This value is not constant - it can vary due to processing techniques, and there may be fluctuations in different batches of products. Usually, the "nominal pore size" (i.e., the average flow pore size of the filtering medium) is used to represent the average size of the filtration channels, with units in the micrometer range. When choosing, it is necessary to be clear: the smaller the pore size value, the smaller the diameter of the particles that can be intercepted, but the liquid flow speed will slow down; conversely, if the pore size is larger, the flow rate will increase but some fine particles may pass through the filter layer. 

In industrial production, the selection of the pore size of the filter cloth directly affects the quality of the filtrate and the moisture content of the filter cake. If the pore size is not precisely determined, problems such as turbidity leakage or blockage may occur. 

Step 1: Measure the particle size distribution in the material

Data can be obtained through sieving or a laser particle size analyzer. Remember an engineering principle: the pore size of the filter cloth should be approximately 1/3 to 1/2 of the median particle diameter. For example, solid particles are mostly around 30 microns, so a 15 micron pore size filter cloth is a safer choice - it can intercept most of the particles without causing rapid clogging.

Note: The specific ratio needs to be adjusted appropriately based on the particle shape (such as needle-like or spherical) and the width of the particle size distribution. It cannot be mechanically applied. 

Step 2: Consider the filtering driving force

During vacuum filtration, the actual pressure difference that the filter cloth bears is relatively low. Therefore, a slightly smaller pore size can be selected. In plate and frame filter presses, the pressure is relatively high. After the fibers are compressed, the pore size will naturally narrow. If the initial pore size is too small at the beginning, it may aggravate clogging or shorten the lifespan of the filter cloth. Therefore, a slightly larger initial pore size can be chosen. 

Step 3: Pay attention to the compatibility between the filter cloth material and the pore size

Polyester filter cloth is suitable for general acid and alkali environments and has a relatively uniform pore size distribution; Polypropylene filter cloth has good alkali resistance, but the flow rate is slightly lower under the same specifications. In some working conditions, a double-layer structure (surface dense layer + support layer) can be selected: the surface layer with smaller pores is responsible for interception, and the bottom layer with larger pores is responsible for flow diversion.

When choosing a double-layer structure, it is necessary to pay attention to the bonding strength between the two layers and the heat setting process to avoid peeling during use.

Changzhou Xiahua Environmental Protection Technology Co., Ltd. specializes in the production and operation of industrial filtration materials for many years, mainly in the chemical industry, and the products are exported to many countries. Xiahua mainly produces the filter cloth, filter bag, pressure filter bag, etc., Xiahua filter cloth, use heart!