Mechanical Face Seals for the Toughest Applications

Federal-Mogul Powertrain sealing technologies protect precision engineering assemblies in the most challenging operating conditions

Friedberg, Germany, 1 November 2016 … Federal-Mogul Powertrain, a division of Federal-Mogul Holdings Corporation (NASDAQ: FDML) designs, develops and manufactures mechanical face seals that are the product of choice to protect precision assemblies from the harsh environments and hostile debris experienced in industries such as mining, construction and agriculture. Unlike lip seals, in which an elastomer lip rubs against a hard steel shaft, face seals provide a metal-to-metal mechanical seal that is highly resistant to wear and the ingress of abrasive particles. This makes them ideal for use in a wide range of applications, including off-highway trucks; construction machinery, tunnelling machines; stone crushers; agricultural and plant equipment.

Face seal technology

A face seal consists of two metal rings, one stationary and the other rotating, each backed by an elastomeric ring that pushes the faces together. A controlled force is exerted by confining the elastomers within a defined space in their respective housings. Because all the relative movement occurs at the contact between the metal rings, the elastomers are only required to provide a static seal, which does not wear. The resilience of the elastomer elements makes the design highly robust and able to accept fluctuations in pressure, radial shaft movement and dimensional changes due to progressive wear of the metal faces.

“Compared to the thin rubber edge of a lip seal, the sealing faces of a mechanical face seal are very hard and have a broader area of contact,” explained Gian Maria Olivetti, Chief Technology Officer, Federal-Mogul Powertrain. “Both these factors increase the wear resistance and robustness of the seal, delivering longer operational life and greater reliability in the very difficult environments typical of off-highway heavy applications such as big dumpers and construction or agricultural equipment.”

Successful development of face seal technology brings together a number of disciplines, requiring an understanding of tribology, elastomers and the factors specific to the application, such as pressure, misalignment and contamination. In use, the topography of the sealing faces changes over time, in a process called tribomutation, as mixed lubrication conditions influence the wear of the surfaces. This requires consistent bulk material properties to ensure uniform characteristics over the life of the seal.

A number of specialized seal ring materials have been developed by Federal-Mogul Powertrain to provide the necessary resistance to wear, seizure, scoring and corrosion. They include pearlitic, and ledeburitic cast irons. These contain various forms of graphite which contributes to good heat transfer and consistent running properties and wear resistance.

The HSL seal

Federal-Mogul Powertrain’s most recent face seal development is the HSL seal, an evolution and special form of the company’s well-proven square bore seal. The HSL seal uses a unique and patented design for the elastomeric part of the seal with an integral dirt exclusion lip and heavy-duty spin protection. These features improve protection significantly, leading to reduced leakage, extended service life and resisting compression from dried mud that could otherwise result in subsequent leakage when the seal has to follow movements.

Federal-Mogul Powertrain has been developing and manufacturing mechanical face seals for more than 60 years. The company’s product engineering and application engineering functions are integrated in a single group to provide maximum support to customers and ensure the optimum solution is produced for each case; whether an adaption of an existing product or a unique design.

“Compared to automotive seals, large face seals are a niche product, with order quantities as low as 10 units, but they are used in applications where the financial consequences of downtime for repair are very significant,” said Andreas Dengler, Manager Application Engineering and Product Development, Federal-Mogul Powertrain. “Our mechanical face seals are widely acknowledged as delivering the utmost reliability and durability in service demanded by the likes of the agriculture, mining and construction industries.”

Development and manufacture

Extensive experience has allowed Federal-Mogul Powertrain to develop a robust analytical tool for face seal design that enables the company to evaluate new seal geometries or resolve pre-existing customer issues through simulation. The virtual study is then validated using a range of laboratory and rig tests including pre-load, spring characteristics, temperature and wear, supplemented by any special requirements, such as long term and ‘mud box’ testing.

Federal-Mogul Powertrain produces face seals at its Friedberg site under the well-known GOETZE®brand, in diameters ranging from 51 mm to 1425 mm. The Friedberg plant is the only production facility in the world capable of manufacturing casted mechanical face seals larger than 1,000 mm in serial production. As recently as 2013, manufacturing capacities for face seals were extended by 60 percent to meet increased demand.

About Federal-Mogul

Federal-Mogul Holdings Corporation (NASDAQ: FDML) is a leading global supplier of products and services to the world’s manufacturers and servicers of vehicles and equipment in the automotive, light, medium and heavy-duty commercial, marine, rail, aerospace, power generation and industrial markets. The company’s products and services enable improved fuel economy, reduced emissions and enhanced vehicle safety.

Federal-Mogul operates two independent business divisions, each with a chief executive officer reporting to Federal-Mogul's Board of Directors.

Federal-Mogul Powertrain designs and manufactures original equipment powertrain components and systems protection products for automotive, heavy-duty, industrial and transport applications.

Federal-Mogul Motorparts sells and distributes a broad portfolio of products through more than 20 of the world’s most recognized brands in the global vehicle aftermarket, while also serving original equipment vehicle manufacturers with products including braking, wipers and a range of chassis components. The company’s aftermarket brands include ANCO®wiper blades; BERU®* ignition systems; Champion®lighting, spark plugs, wipers and filters; Interfil®filters; AE®, Fel-Pro®, FP Diesel®, Goetze®, Glyco®, Nüral®, Payen®and Sealed Power®engine products; MOOG®chassis components; and Ferodo®, Jurid®and Wagner®brake products and lighting.

Federal-Mogul was founded in Detroit in 1899 and maintains its worldwide headquarters in Southfield, Michigan. The Company has more than 53,000 employees globally. For more information, please visit www.federalmogul.com.

*BERU is a registered trademark of BorgWarner Ludwigsburg GmbH

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