Considerations for Dual Pressurized Gas Seals in Pump Applications

Mechanical seals continue to be the predominant technology for shaft sealing in centrifugal pumps and other rotating equipment. While most mechanical seals are designed to operate on a liquid film, there are options for designing seal faces which function reliably while operating on a hydrodynamic gas film. In a dual pressurized seal (Arrangement 3), gas seals can provide unique benefits in terms of energy costs, reliability, and emissions control. Dual gas seals however require special considerations when reviewing potential applications. These include the nature of the process fluid, the design of the pump, and the operation of the equipment. In addition, the success of the installation will depend on the design and reliability of the gas supply system. The user must be aware of these requirements during commissioning and standby operations. With careful selection and operation of the seal and sealing system, dual pressurized gas seals can be an important option for many pump applications.