Rotary shaft seals, also known as lip seals, are ideal for rotating equipment. They seal these rotating parts such as swivel bores, strut seals, hydraulic pumps, etc. A rotary seal consists of a sealing lip, a garter spring and a metal housing. The solidity of the metal provides a rigid and secure hold for the connected parts. Lip seals are elastomers that perform the actual sealing function.Rotary shaft seals are extremely versatile and can be made from a variety of materials from hard metals to plastics. Common materials are steel, brass, silicone rubber and rubber such as NBR and FKM.
Material Composition of Rotary Shaft Seals
Rotary shaft seals are primarily composed of two key materials: a flexible elastomer and a supporting metal frame. This combination optimizes the seal’s ability to maintain a safety barrier while accommodating the dynamic movement of the rotating shaft.
(1) Elastomer material
The primary sealing element of a rotary shaft seal is the flexible lip that is in direct contact with the shaft. This lip is usually made of an elastomeric material, more commonly NBR or FKM. The choice of elastomer depends on the specific application, operating conditions, and fluids that the seal will encounter.
NBR is widely used in rotary shaft seals due to its excellent oil resistance and cost-effectiveness. It provides reliable sealing for applications involving lubricating oils, fuels and non-corrosive liquids. FKM has excellent resistance to a wider range of chemicals, including corrosive liquids, fuels and high temperature environments. FKM rubbers are suitable for applications where extreme conditions or exposure to corrosive substances are expected.
(2) Metal frame
Supporting the elastomeric lip is a metal frame that provides structural integrity and stability to the seal, usually made of stainless steel or another corrosion-resistant metal. The frame strengthens the seal against deformation and maintains proper pressure on the rotating shaft to ensure an effective seal.
The material composition of a rotary shaft seal involves a delicate balance between elastic properties and structural support. NBR and FKM form a harmonious combination with the carefully selected metal frame to effectively seal the rotating shaft while maintaining durability and resistance to various operating conditions. The selection of these materials is guided by the specific requirements of each application, ensuring that rotary shaft seals perform their vital sealing role reliably and efficiently.
Functions and benefits of rotary shaft seals
Seals protect equipment from friction and wear. Well-lubricated equipment can run for years, especially in vacuum applications where the seal prevents outside air from entering the internal duct or chamber, and in most other applications it prevents contamination and exposure to environmental elements, and secondly, in conveying In pumping applications of various types of fluids, seals prevent any fluid from leaking or spilling to the outside.
Industrial Applications of Rotary Shaft Seals
These seals are suitable for use in virtually all industries, especially those where rotating, agitating or oscillating motion is critical. The following are some application areas: such as food and beverage, water and wastewater, chemical industry, oil and gas, pneumatic and hydraulic applications, and boiler and heater applications, etc.
Rotary shaft seals are a category of oil seals. They are mainly used in the equipment of rotating shafts. Their main function is to prevent leakage of the internal medium of the equipment and the intrusion of foreign objects from the outside, thereby sealing.
To sum up, rotary shaft seals can provide sealing and scraping functions for rotary and rotary motion under low pressure and high speed conditions. They perform two important functions: the primary function is to preserve the bearings in the system or the lubricant of the system to avoid leakage; the second function is to prevent contamination of the system by foreign particles or other environmental influences. Radial rotary shaft seals typically consist of a metal skeleton (or lagging) and a spring-loaded rubber sealing lip.
