Importance of valve seals

                In real life, the production valve seal damage was common, light can cause waste, or bring danger to life, such as tap water valve leak, or causing serious consequences, such as the chemical industry the poisonous and harmful, inflammable, explosive and corrosive medium leakage in the nature of, serious threat to personal safety and property safety, and environmental pollution accidents.A rely on external force rotating drive open and close valves are designed with a sealing device used in the packing chamber with a certain number of packing sealing ring, so as to achieve the sealing effect, but how is the sealing situation?Valve packing leakage is one of the most vulnerable parts of the valve leakage fault, but there are two reasons.

Fillers are now mainly used:

1.Asbestos, because of the presence of asbestos material chloride ion corrosion of the valve stem, in addition to asbestos contains carcinogenic substances, harm to human health, the country has taken the parts of the product banned or less use;

2.Synthetic resin and synthetic fiber, this kind of product or on the using range is restricted, such as the use of pure ptfe temperature to 150 ℃ or less and filled ptfe 250 ℃ or less and ptfe particles filler compensation performance is poor, also is only applicable to low pressure valves, four fluorine fiber, carbon fiber or both mix packing, and the price is too high, bad promotion;

3.When expanding graphite, serious electrochemical corrosion will occur.

Second, the corrosion problem is also a factor.

Corrosion:

1.Stem of natural oxidation corrosion, due to the stem packing table in the oxidation, the formation of iron oxide (rust), resulting in thin stem, resulting in leakage;

2.Leakage caused by chloride ion corrosion of asbestos packing;

3.Corrosion of stainless steel by graphite packing;

4.Medium corrosion of valve stem, etc.