Rotary seals are highly efficient lip seals that keep rotating machinery and equipment components working properly. They provide bearing protection, lubricant retention, exclusion of contaminants, and minimize or eliminate fluids leaking. They are able to perform well for long periods of time with a high rotating speed and in temperatures anywhere from -60°F to 200°F. Rotary seals perform even in poorly lubricated and dry conditions.
Quick links to Rotary Seals Information
Design of Rotary Seals
Rotary seals have many different profiles, but they are usually round and shaped much like an o-ring. They are always symmetrical, meaning their cross sections are mirror images of each other. Because this type of seal is usually made out of Teflon, a material that cannot melt, they are all manufactured by the sintering process. Sintering takes Teflon in powder form and places a dense amount in a rotary seal-shaped mold subjected to high heat in an industrial furnace for a certain time before being rapidly cooled. This forces the powder to adhere together and condense into a hard, black plastic or rubber-like product that is inert, resistant to most chemicals and substances, and can withstand large amounts of pressure and even vacuum environments. While the primary function of seals in rotary applications is to retain the bearing lubricant, they also enhance the life and performance of the bearing by minimizing all dirt, oil, and water ingress.
Rotary Seal Materials
Some are made of metal or plastic materials, but the most popular material for rotary seals is Teflon or PTFE. This material is inert, meaning it will not react with most chemicals, and it performs well under high pressures and in vacuum environments. Some Teflon rotary seals are made specifically for food and beverage processing or pharmaceutical manufacturing applications and must meet strict FDA requirements. Most Teflon seals contain strengthening additives like graphite, bronze, glass, and carbon.
Applications for Rotary Seals
Rotary seals provide a seal for oxygen, gasses, water, other fluids, hydrocarbons, and food materials. They are found in any machinery with a spinning component within the hydroelectric power, hot and cold steel rolling, chemical and petroleum processing, automotive manufacturing, food and pharmaceutical, machine tooling, pulp, paper and textile processing, and hydraulic industries. Gearboxes, marine propulsion systems, process mixers, tunnel boring machines, recreational vehicles, and other machines and equipment use rotary seals, which, when used correctly, lengthen the system's lifespan and increase its durability.