Dry Gas vs Wet Seals–It’s No Contest
In industrial applications involving rotating equipment, such as compressors, pumps, or turbines, the points at which the rotating and non-rotating parts of the machinery meet are prone to leaking. Whether they leak the liquid or gas that is being treated or they leak the substance being used to lubricate the mechanism, these leaks can become a serious problem over time. Not only does the leaking substance need to be constantly topped off to replace the amount lost through leakage, but this leaking substance is quite often hazardous. Toxic chemicals and other pollutants must be kept contained. To keep rotating equipment from leaking, companies like Stein Seal Industrial develop elaborate mechanical sealing systems for a vast array of industrial applications.
For the most part, these seals are either dry gas seals or wet seals. Each type has its strengths and weaknesses, and the success of each application depends largely on which type of seal is used. Choosing correctly requires the consideration of a number of variables.
Operating Environment
When processing gasses in high-pressure, high-temperature environments, a dry gas seal is often the right choice. Wet seals are better suited to processing liquids through centrifugal pumps, mixers, etc.
Leakage Control
When hazardous chemicals are involved and even minor gas leakage is to be avoided, dry gas seals are the way to go. Wet seals will offer the best performance when processing liquids, though some leakage is still likely to occur over time.
Lubrication
Dry gas seals do not require a continuous source of liquid lubrication. Instead, they use a tiny amount of gas to create a seal. This reduces friction between the lubricated parts while maintaining a gas barrier to prevent leakage. The result is an effective seal requiring minimum maintenance. Wet seals must be continually lubricated and cooled, and require more maintenance due to greater wear and tear.
Reliability
Known for their reliability and extended operational life, dry gas seals experience less wear over time as compared with wet seals. Wet seals require more maintenance and can have much shorter operational lives, particularly when used with abrasive or corrosive liquids.
Contaminant Tolerance:
In processes where impurities may enter the system, dry gas seals may prove unreliable. Highly sensitive, dry gas seals require intensive filtration to avoid damage. Wet seals, on the other hand, are less sensitive to contaminants suspended within the process fluid.
Cost:
Perhaps not surprisingly, dry gas seals are typically more expensive at the outset than wet seals. However, over time, the high durability and low maintenance of the dry gas seal can offset initial costs. In the short term, wet seals can prove more cost-effective in the short term.
Stein Seal Industrial excels at designing and building mechanical seals of all varieties. Our dry gas and wet seals are employed throughout industry to the benefit of industrial applications everywhere.