Domsel Seal A

Composition and construction

The Domsel Seal A is a radial lip seal with one sealing lip and an elastomer coated OD (elastomer-coated outside diameter). That coating helps it seal well in the bore and can improve sealing against minor irregularities in the housing. A key characteristic is that the seal is designed for exceptionally low friction: the friction torque is approximately 50–65% lower than with conventional seals, which also significantly reduces frictional heat. This makes circumferential speeds of up to 32 m/s possible, and the type is designed for pressures up to 15 bar. The lip is constructed in such a way that it does not “cut into” the shaft; scratches on unhardened shafts are prevented, provided that the medium is not abrasive. For installation, it is good to know that the Seal A has a design in which the sealing lip is aligned with the pressing direction (lip direction in line with the press-in direction).

Applications and why it is so suitable there

The Domsel Oil Seal A is widely used in engines, gearboxes, spindles, pumps, compressors, fan construction, vehicle manufacturing, and for example welding rollers. The main reason is the combination of low friction (less heat at speed), high load capacity (pressure/speed), and broad applicability across media. The seal is suitable for liquids, gases, air, and also steam up to 120 °C. In addition, these seals are known for high chemical resistance and long service life, and many models are suitable for use in the food industry due to FDA compliance.

Materials: NBR, FKM (FPM), HNBR, FFKM, EPDM or VMQ (Silicone)

Within this category, the Domsel Oil Seal A can be supplied with several lip materials, depending on the medium, temperature and chemical exposure. NBR (Nitrile) is the practical default for many mineral-oil and grease applications at normal temperatures. FKM/FPM (Viton®) is typically chosen when higher temperatures and stronger chemical resistance are required. HNBR offers improved heat resistance and mechanical strength compared with NBR and is often selected when conditions are tougher but a fully fluorinated material is not necessary. EPDM is mainly used for hot water, steam-like environments and certain chemicals, but it is generally not suitable for mineral oils and greases. VMQ (Silicone) is valued for low-temperature flexibility, but it is usually less wear-resistant in heavy dynamic service. FFKM is the option for the most aggressive chemicals and the highest temperature margins, typically used when other elastomers do not provide enough resistance.

Comparison with Domsel Seal B and Domsel Seal A-SF

The Domsel Seal A is the “A” version with one lip, where the lip is in line with the press-in direction. The Domsel Seal B is the comparable model for situations where you need a different lip orientation, for example when the sealing direction/medium side ends up reversed relative to your installation. The Domsel Seal A-SF is the more compact variant within the same family for tight installation spaces, intended when you want to maintain the A logic but have less axial space available.

How to choose the right Domsel Oil Seal A

Start with the dimensions: the shaft diameter (d), the bore/outside diameter (D), and the width/height (b). Then place the operating conditions alongside: circumferential speed, pressure, temperature, and the medium. The Domsel Seal A is intended for high-performance applications and offers margin on speed and pressure, with a wide temperature range depending on the version and the chosen elastomer. Next, select the lip material based on the actual medium and temperature. As a rule of thumb, NBR is used for standard oil/grease duty, HNBR for tougher conditions with better heat and strength, FKM for higher temperatures and broader chemical resistance, EPDM for hot water/steam-like media (not mineral oils), VMQ for low-temperature flexibility, and FFKM when maximum chemical resistance and temperature margin are required. Finally, it is important that fit and shaft condition are correct: a radial shaft seal stands or falls with correct tolerances, a suitable shaft surface, and a neat lead-in/chamfer so that the lip is not damaged during installation.

When it comes to sealing rotating machine parts, the Domsel Seal A is a reliable choice that offers superior performance and durability. Its low frictional torque, high chemical resistance, and wide temperature range make it a versatile solution for various industries. Trust the Domsel Seal A to deliver efficient and long-lasting sealing in your machinery applications.

If you want more information or do you have any questions, feel free to contact us.

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