A dry gas seal is a type of mechanical seal used to contain gases without incursion from contaminants or inadvertent release of the gas into the surrounding environment. Such seals are available for use with a variety of compressed systems, including in harsh environments where other seals might be prone to failure. They operate without the need for lubricants, and when they are installed properly, they can have a very long operating life with minimal problems.
Numerous companies produce dry gas seals and components. The basic design consists of a set of rings, one stationary and mounted to the system, the other able to freely rotate. As the rotating ring moves, gas can flow through a series of grooves, forcing the rings apart and creating a barrier so their faces do not touch. This prevents the release of gas from the system, while also keeping contaminants out. If contaminants force their way into the seal, they cannot get past the stationary ring.
The dry gas seal design can be used in applications like oil and gas drilling as well as gas handling in labs and industrial facilities. The tolerances of the design are extremely narrow. This is important in installation, where small errors can make the seal useless or cause it to fail unexpectedly. The precision machining of the dry gas seal can keep out even the finest of contaminants, as long as it is properly mounted and maintained.
Lack of lubrication means that the seal requires less maintenance. Technicians do not need to break it down and clean it, because there shouldn't be deposits of lubricants. There is also less wear on the seal in the long term, which can promote a longer working life. Periodic examination of the seal is still necessary to check for signs of fatigue, and a monitoring system can be put in place to ensure that seals are regularly reviewed by qualified personnel.
A new system can be fitted with a dry gas seal from the start, if desired. It is also possible to retrofit to replace a seal on an existing system with this design. A variety of sizes are made with different components to handle conditions with extreme heat or cold, unusually small contaminants, and other challenges. It is important to select the right dry gas seal product for a given application to reduce the risk of problems while the seal is in operation.