The material of the packing is divided into ceramic, metal and plastic.
(1) Ceramic packing
Ceramic packings have good corrosion resistance and heat resistance. Ceramic packings are inexpensive, have good surface wetting properties, and are brittle and brittle. It is widely used in gas absorption, gas washing, liquid extraction and the like.
(2) Plastic packing
The material of the plastic packing mainly includes polypropylene (PP), polyethylene (PE) and polyvinyl chloride (PVC), etc., and polypropylene is generally used in China. The plastic packing has good corrosion resistance and is resistant to corrosion by general inorganic acids, alkalis and organic solvents. It has good temperature resistance and can be used at temperatures below 100 °C for a long time.
The plastic packing is light, inexpensive, has good toughness, is resistant to impact and is not brittle, and can be made into a thin-walled structure. Its large flux and reduced pressure are used in absorption, desorption, extraction, dust removal and other devices.
A disadvantage of plastic packings is their poor surface wetting properties, but their surface wetting properties can be improved by proper surface treatment.
(3) Metal packing
Carbon steel packings are low in cost and have good surface wetting properties, and should be preferred for non-corrosive or low-corrosive systems.
Stainless steel packings are highly resistant to corrosion and generally resistant to corrosion by common systems other than Cl-, but they are expensive and have poor surface wetting properties. In some special occasions (such as decompression concentrate at very low spray density) Distillation process), the surface needs to be treated in order to achieve good results.
packings made of titanium, special alloy steel and other materials are expensive and generally only used under some highly corrosive systems.
In general, the metal packing can be made into a thin-walled structure, which has large flux, low gas resistance, high impact resistance, can be used under high temperature, high pressure and high impact strength, and has the widest application range.