Mechanical seal with a secondary seal material

Mechanical seal with a secondary seal requires the following properties:

① good flexibility, suitable hardness and compression set is small;

② high resistance, low temperature aging properties;

③ compatible with the media difficult to produce swelling, melting reduction, decomposition and hardening;

④ smaller coefficient of friction, wear and some tear strength.

1, nitrile rubber (NBR) rubber, nitrile butadiene and acrylonitrile by suspension polymerization in the copolymers obtained.

2, hydrogenated nitrile rubber (HNBR) is superior to NBR, with a temperature range of -40 ~ +1500 C, good oil resistance than NBR, fluorine rubber, resistant to hydrogen sulfide than good.

wire cable trays, cable management systems, basket cable tray

3, fluorine rubber

Viton is a fluorine-containing high polymers. There are two main domestic fluorine rubber models. F-23s equivalent of the foreign Kyle-F (Kel-F) type; fluorine -26 equivalent foreign Vital (VITON) type. FKM has excellent high temperature resistance, oil resistance, high vacuum and corrosion resistance, but not in the use of ketones and esters in solution, and the bad cold, compression Great.

4, ethylene-propylene rubber

EPDM is formed by the polymerization of ethylene and propylene, are divided into binary and ternary copolymers.

5. Silicone rubber (SILICON RUBBER)

Silicone rubber is a synthetic silicone and hydrocarbons. Good high and low temperature, there is less compression, and excellent dielectric properties. The disadvantage is that silicone rubber at room temperature, tear strength and abrasion resistance than other types of plastic is poor, does not apply to the low point of benzene, mineral oil, will be the first in the high-pressure steam generated in the decomposition.

6, polytetrafluoroethylene (PTFE) have a larger temperature range (-150 ~ 2500C); very low coefficient of friction and self-lubricating, surface adhesion, good chemical stability. The only way to erode the plastic is molten alkali metals and in high temperature and pressure of fluorine. Under the load, any temperature will creep more than 3430C, the decomposition will produce toxic fumes.

7, used as a secondary seal of the other materials have neoprene rubber (CR), butyl rubber (HR), epichlorohydrin rubber.

8, used as a secondary seal of the other materials have filled PTFE, flexible graphite, asbestos and rubber composite materials. Mainly used for high temperature applications.