What are the commonly used materials for solenoid valve sealing?

Solenoid valves are electromagnetically controlled industrial equipment used in industrial control systems to adjust the direction, flow, speed and other parameters of the medium. The solenoid valve is controlled by the electromagnetic effect, and the main control mode is controlled by the relay. There are currently three most commonly used sealing materials for solenoid valves. The following is a brief introduction of the Wanhua Hardware Machine Grid:

1. NBR nitrile rubber (nitrile butadiene rubber)

Made of butadiene and acrylonitrile by emulsion polymerization, the nitrile rubber is mainly produced by low-temperature emulsion polymerization, which has excellent oil resistance, high wear resistance, good heat resistance and strong adhesion. The disadvantages are poor low temperature resistance, poor ozone resistance, poor electrical properties, and slightly lower elasticity.

In addition, it has good water resistance, air tightness and excellent bonding properties. Widely used in the manufacture of various oil-resistant rubber products, a variety of oil-resistant gaskets, gaskets, casings, flexible packaging, soft rubber hoses, printing and dyeing rubber rollers, cable rubber materials, etc., in the automotive, aviation, petroleum, copying and other industries become essential Elastic material.

Nitrile rubber has excellent oil resistance, its oil resistance is second only to polysulfide rubber and fluororubber, and it has wear resistance and air tightness. The disadvantage of Dingqing Rubber is that it is not resistant to ozone and aromatic, halogenated hydrocarbons, ketones and ester solvents. It is not suitable for insulating materials.

Main use: Nitrile rubber is mainly used in the production of oil-resistant products, such as oil-resistant pipes, tapes, rubber diaphragms and large oil bladders. It is commonly used in the production of various oil-resistant molded products, such as O-rings, oil seals, cups, diaphragms, valves. , bellows, etc., also used to make rubber sheets and wear parts.

Second, EPDM EPDM (Ethylene-Propylene-Diene Monomer)

EPDM rubber is a terpolymer of ethylene, propylene and non-conjugated diene, which was commercialized in 1963. The annual consumption worldwide is 800,000 tons. The most important feature of EPDM is its superior resistance to oxidation, ozone and erosion. Since EPDM is a polyolefin family, it has excellent vulcanization characteristics. Among all rubbers, EPDM has the lowest specific gravity. It absorbs a large amount of fillers and oils and has little effect on properties. Therefore, it is possible to produce a rubber compound which is inexpensive.

Molecular structure and properties

Structure: EPDM is a terpolymer of ethylene, propylene and a non-conjugated diene. Diolefins have a special structure, only one of the two bonds can be copolymerized, and the unsaturated double bonds are mainly used as a crosslink. The other unsaturated will not become the polymer backbone, it will only become the side chain. The main polymer chain of EPDM is fully saturated. This property makes EPDM resistant to heat, light, oxygen, and especially ozone. EPDM is essentially non-polar, resistant to polar solutions and chemicals, low in water absorption, and has good insulating properties.

Features: 1, electrical performance; 2, elasticity; 3, adhesion; 4, low density and high filling; 5, resistance to hot water; 6, water vapor resistance; 7, aging resistance; 8, corrosion resistance .

Third, VITON fluororubber (FKM)

The fluorine-containing rubber in the molecule has various types depending on the fluorine content, that is, the monomer structure; currently, the hexafluoride-based fluorocarbon rubber is first marketed by DuPont under the trade name "VITON". High temperature resistance is superior to silicone rubber... Chemical resistance, most oils and solvents (except ketones and esters), weather resistance and ozone resistance are good, but cold resistance is poor; generally used in steam locomotives, B Equivalent products, seals of chemical plants, the temperature range of -20 Â° C ~ 260 Â° C, low temperature requirements for low temperature type can be applied to -40 Â° C, but the price is higher.