A Comprehensive Guide for Floating Seals

Mon January 15, 2024


What is a Floating Seal?

Also known as mechanical face seals or heavy duty seals,it also called Duo cone seal or metal seals. Floating seals are designed to solve rotary applications in extremely harsh environments, withstanding severe wear and preventing the ingress of harsh and abrasive external media. It is a high-performance seal that combines a floating ring seal, a gap seal, and a comb seal, utilizing the tension of the oil film to effectively prevent leakage.

There are two mechanical face seals: Type DO, which uses an O-ring as the secondary sealing element, and Type DF, which uses an elastomer with a diamond-shaped cross-section as the secondary sealing element instead of an O-ring. Both types consist of identical metal sealing rings mounted face-to-face in two separate housings on the abrasive sealing surface. The metal rings are centered within their housings using an elastomer element. One-half of the mechanical face seal remains stationary in the housing while the other half rotates with its opposite face.

Mechanical Face Seals are primarily used to seal bearings in construction machinery or production plants that operate under extremely harsh conditions and are subject to severe wear. These include tracked vehicles such as excavators and bulldozers, conveyor systems, heavy trucks, axles, tunnel boring machines, agricultural machinery, and mining machinery. They have also proved useful in gearboxes, mixers, agitators, wind power stations, and other applications with similar conditions or requiring less maintenance.

Floating seals are mechanical face seals designed to withstand harsh environments and prevent leakage in rotating applications. They are commonly used in construction machinery and manufacturing plants to protect bearings from wear and contamination.

Floating Seal

Structure principle

A floating seal consists of two identical metal rings and two rubber rings; its working principle is that a pair of rubber rings in support of the metal ring and the cavity form a closed space (but not in contact with the shaft) when rotating the metal ring, the two ground surfaces of the ring closely match and slide relative to each other, on the one hand, to ensure that the operation of the good, on the other hand, effectively sealing off the outside world of dust, water, sludge, etc., to protect the internal lubricating grease from leaking. Leakage.

Sealing Principle

The sealing principle of a floating oil seal is that two floating rings rely on the deformation of the O-ring by axial compression, resulting in compression force on the sealing end face of the floating ring. With the uniform wear of the sealing end face, this elastic energy stored by the O-ring is gradually released, thus playing an axial compensation effect. The sealing surface can maintain a good fit within a set period, and the general sealing life is more than 4000 hours.

Installation Note

(1) Before installing the floating oil seal, check whether the contact surface is too rough and whether there is any damage, especially whether there is any longer scar along the axial direction. If the contact surface is too harsh, it is easy to damage the oil seal or accelerate the wear of the lip and damage its sealing performance. If the contact surface is improperly disassembled and assembled to cause more serious blunt force scars, it will make the oil seal lip and the contact surface fit poorly, resulting in oil leakage. In the above two cases, the scarred part of the surfacing welding should be re-lathe round according to the specified journal size or the new shaft. If the contact surface is only metal burrs or shaft head fretting, etc., it can be used to file grinding leveling to prevent the installation of oil seals when the oil seal lip is injured.

(2) Check that the floating oil seal lips are not broken and injury cracks or oily corrosion, such as these undesirable phenomena, should be replaced with a new floating oil seal.

(3) Floating seal installation skeleton oil seal, to prevent the oil seal lip from being stretched, deformed, or scratched, must use a special installation tool. If there is no such tool, the following simple method can be used for installation: first, in the journal and even the head part, roll a layer of transparent hard plastic film (commonly known as cellophane), smear a little oil on its surface, the oil seal set into the head wrapped in plastic film, even force the oil seal slowly pushed to the journal, and then pull out the plastic film. Note: Do not install the lip in the wrong direction; it should be oriented to the inner side of the stored oil, and the side with the trademark and specification should be oriented to the outer side. Because the lip can only do one-way sealing, if the oil package is reversed, it will inevitably lead to oil leakage, and the sealing effect is weakened or ineffective. To avoid the oil package being crooked or with a hammer bar and other tools on the surface of the oil seal knocking and beating otherwise, it is easy to make the oil seal by injury.

(4) keep the oil seal (especially lip parts) and journal parts clean in the floating oil seal installation process, and pay attention to not making the oil seal self-tightening spring jump out of the spring groove. If the self-tightening spring relaxation, elasticity is weakened, depending on the situation, cut off a section of its own, the two ends can be firmly connected to continue to use.

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