The Domsel Oil Seal A (also referred to as oil seal A) is a high-performance oil seal for rotating shafts: a rotary shaft seal within the family of radial shaft seals. It is a single lip oil seal used to prevent leakage along a rotating shaft and to keep the medium (such as oil or grease) where it belongs. The Domsel Oil Seal A was developed for applications where a standard oil seal often creates too much friction, runs too hot, or wears out faster. Precisely because of its focus on low friction and stable sealing at higher speeds and under heavier conditions, this type is popular in machine building and drive technology. Within the domsel and domsel seals range, the Seal A is therefore a clear “go-to” solution when you are looking for a reliable, efficient radial shaft seal.
A Domsel Seal A is a rotary shaft seal, also known as a radial shaft seal or rotary lip seal. The seal closes the gap between the rotating shaft and the fixed housing, helping to prevent leakage and contamination.
The sealing lip is designed to align with the pressing direction. This supports reliable sealing in standard rotary applications.
Compared with conventional oil seals, the sealing lips of Domsel Seal A can achieve approximately 50 to 65% lower frictional torque, depending on the selected version and operating conditions. Lower friction can reduce heat generation around the sealing lip and support efficient operation, reduced wear and longer service life in suitable applications.
Domsel Seal A can be used for circumferential speeds of up to 32 m/s and pressures of up to 15 bar, depending on the selected seal version, material, medium, lubrication, shaft condition and installation. Depending on the selected material and application, the seal range can be used in temperatures from -45 °C to +300 °C. For steam applications, selected versions can be used up to 120 °C.
Maximum values for speed, pressure and temperature should always be checked for the selected product version. These values cannot automatically be combined in one application without technical verification.
Domsel Seal A oil seals are used in many types of rotating equipment, including industrial gearboxes, electric motors, pumps, compressors, agricultural machinery, spindles, fan constructions, vehicle manufacturing, welding rollers, drive units and mechanical assemblies with rotating shafts.
The seal is suitable where low friction, reliable sealing and chemical resistance are important. The sealing lips are designed to help prevent scratches on the shaft, even on unhardened shafts, provided that the sealed medium is non-abrasive and the shaft surface is suitable.
Domsel Seal A combines low-friction sealing with a wide operating range. The lower frictional torque compared with conventional oil seals helps reduce heat generation around the sealing lip. In rotating equipment, this can support efficiency, wear reduction and service life.
The seal range offers strong chemical resistance and can be used for different media, including liquids, gases, air and steam, depending on the selected version and material.
Key technical characteristics include:
Always check the selected product version when FDA compliance, high temperature resistance, pressure resistance or chemical compatibility is required.
Start with the dimensions of the existing seal or the technical drawing of the application. The inside diameter must match the shaft diameter. The outside diameter must match the housing bore. The height must fit the available installation space.
If you are replacing an old seal, check whether the markings are still readable. These markings often include the size, material or type code. If the markings are no longer visible, measure the shaft, housing and seal height carefully.
Dimensions are only the first step. A seal with the right size can still be unsuitable if the material, profile or operating conditions do not match. Check the medium, temperature, pressure, shaft speed, shaft condition, lubrication and installation method before ordering.
A worn or damaged shaft surface can reduce sealing performance, even when the seal itself is correct. Grooves, corrosion, contamination or incorrect installation can cause leakage or premature wear.
Domsel Seal A oil seals are available in materials such as NBR and FPM/Viton. The right material depends on the medium, temperature, chemical exposure and operating conditions.
NBR is commonly used for standard industrial oil seal applications. It is often selected for mineral oils, greases and general machine sealing where the temperature and chemical load remain within standard limits.
FPM, also known as FKM or Viton-type fluoroelastomer, is used for applications with higher temperatures or stronger chemical demands. It offers better resistance to many oils, fuels and chemicals than standard NBR. This makes FPM/Viton suitable for demanding sealing applications where heat resistance and chemical compatibility are important.
For food or pharmaceutical applications, also check whether the selected version is available in an FDA-compliant material and whether the required documentation is available.
| Property | NBR | FPM |
|---|---|---|
| Also known as | Nitrile, Buna-N | FKM, Viton |
| Typical applications | Standard industrial oil seal applications | Higher temperatures or stronger chemical demands |
| Common media | Mineral oils, greases, general machine sealing | Many oils, fuels, chemicals and synthetic oils |
| Typical temperature range* | approx. -40 °C to +100 °C | approx. -20 °C to +200 °C |
| Chemical resistance | Good within standard limits | Strong, including many aggressive media |
| Relative cost | Economical / standard | Higher |
*Indicative general ranges. Always check the temperature, pressure and chemical ratings of the selected Domsel Seal A version before ordering.
Domsel Seal A is one specific profile within the wider Domsel oil seal range. Other Domsel versions, such as A-SF, AB, AC, B, B-SF and BC, may be used for different profiles or installation requirements.
If your machine drawing, old seal or technical documentation mentions another Domsel type, choose the matching version. Similar-looking oil seals can differ in profile, sealing design, material or installation behaviour. Selecting the wrong profile can lead to leakage, incorrect fit or reduced service life, even when the dimensions appear to match.
If you are not sure which Domsel Seal A oil seal is suitable for your application, our team can help you check the right size, material and profile. Share the shaft diameter, housing diameter, seal height, medium, temperature, pressure and shaft speed if available.
Use the product overview to select a seal directly when the size and material are known. For technical applications, uncertain replacements or demanding conditions, contact us first so we can help you select the right radial shaft seal.
The Domsel Oil Seal A is a high-performance rotary shaft seal (radial shaft seal) with one sealing lip, intended for sealing rotating shafts in machine-building applications.
Both are part of the same domsel seals family, but A and B differ in lip orientation/application. You choose B when the lip orientation of A does not make sense with your medium side and installation.
If you want the same “A” logic, but have too little installation space and need a slimmer version.
Within this category, NBR (Nitrile), HNBR, FKM/FPM (Viton®), EPDM, VMQ (Silicone), and FFKM are available.
Yes, this type is designed for high performance, including pressures up to 15 bar and circumferential speeds up to 32 m/s, provided it is correctly selected and installed.