doubleseal

A doubleseal is a type of mechanical seal used in rotating equipment to prevent leakage of process fluids. It consists of two independent sealing faces that are separated by a small gap. This gap is typically filled with a barrier fluid, which is maintained at a pressure higher than the process fluid. The barrier fluid serves multiple purposes, including lubrication of the seal faces, cooling, and preventing the ingress of air or process fluid into the seal.

There are two main types of doubleseals: wet seals and dry seals. Wet seals use a liquid barrier fluid, while dry seals use a gas, typically nitrogen, as the barrier fluid. Wet seals are more common and are used in a wide range of applications, including pumps, compressors, and mixers. Dry seals are typically used in high-pressure or high-temperature applications where liquid barrier fluids may be unsuitable.

Doubleseals offer several advantages over single mechanical seals, including enhanced safety, improved process reliability, and extended seal life. By providing a barrier fluid, they can prevent hazardous or toxic process fluids from leaking into the atmosphere. They can also help to maintain process integrity by preventing contamination. The lubrication and cooling provided by the barrier fluid reduce wear on the seal faces, leading to longer operational periods between maintenance. The selection of a doubleseal depends on factors such as the process fluid, operating pressure and temperature, and safety requirements.