• page_banner

Floating oil seal features

Floating oil seal features

Floating oil seal is a common name for floating seals, belonging to a type of mechanical seal in dynamic seals. It has excellent sealing performance in harsh working environments such as coal powder, sediment, and water vapor. It is a compact mechanical seal mainly used in low speed and heavy load situations. It has the advantages of wear resistance, automatic compensation after end face wear, reliable operation, and simple structure, and is widely used in coal mining machinery. Such as bulldozer walking mechanism, scraper conveyor head (tail) sprocket components, roadheader loading mechanism and cantilever section, left and right cutting drums and reducers of continuous coal mining machines, etc.

The floating oil seal is used in the planetary reducer of the walking part of construction machinery to dynamically seal the end face of the component. Due to its high reliability, it is also used as a dynamic seal for the output shaft of the dredger bucket wheel. This type of seal belongs to mechanical seals and generally consists of a floating ring made of ferroalloy material and a matching nitrile rubber O-ring seal. Floating rings are used in pairs, one rotating with the rotating component and the other relatively stationary, which is very different from the oil seal ring


The floating oil seal is composed of two identical metal rings and two rubber rings. Its working principle is that a pair of rubber rings form a closed space with the cavity (but not in contact with the shaft) under the support of the metal rings. When rotating, the two ground surfaces of the metal rings closely match and slide against each other, ensuring good operation on the one hand, and effectively sealing off external dust, water, sludge, etc., to protect the internal lubricating grease from leakage.


The sealing principle of a floating oil seal is that the deformation of two floating rings caused by axial compression of the O-ring generates a compressive force on the sealing end face of the floating ring. With the uniform wear of the sealing end face, the elastic energy stored by the  Rubber  O-ring is gradually released, thereby playing an axial compensation role. The sealing surface can maintain good adhesion within the set time, and the general sealing life is over 4000h.

Floating oil seal is a special type of mechanical seal developed to adapt to harsh working environments. It has the advantages of strong pollution resistance, wear resistance, impact resistance, reliable operation, automatic compensation for end face wear, and simple structure. It is most commonly used in engineering machinery products, and is also widely used in various conveyors, sand treatment equipment, and concrete equipment. In coal mining machinery, it is mainly used for the sprocket and reducer of scraper conveyors, as well as the transmission mechanism, rocker arm, drum, and other parts of coal mining machines. This type of sealing product is widely and mature in the application of engineering machinery and equipment, but in other industries, due to its limited usage, lack of basic theoretical data and usage experience, the failure phenomenon during use is relatively common, making it difficult to achieve the expected effect.

Maintain a certain gap between the floating ring and the rotating shaft, which can float freely, but cannot rotate with the rotating shaft. It can only perform radial sliding floating and maintain a certain eccentricity with the shaft center under the action of gravity. When the shaft rotates, sealing fluid (often oil) is input from the outside to form an oil film at the gap between the shaft and the floating ring. Due to the action of oil wedge force generated during shaft rotation, a certain amount of oil film pressure is maintained within the oil film, allowing the floating ring to automatically maintain “alignment” with the center of the shaft, greatly reducing the gap and effectively achieving sealing for fluid medium leakage. Its advantages are stable sealing performance, reliability, and long service life; The working parameter range of the seal is relatively wide (with a working pressure of up to 30 MPa and a working temperature of -100~200 ℃); Especially suitable for sealing gas media in centrifugal compressors, it can also achieve no leakage to the atmospheric environment, and is suitable for sealing flammable, explosive, toxic, and precious gas media. The disadvantage is that the processing requirements for floating rings are high, requiring a specialized sealing oil system; There are many internal leaks, but they still belong to the nature of internal circulation, which is qualitatively different from the leakage of mechanical seals. Widely used for dynamic seals in centrifugal compressors.

Post time: Nov-10-2023