Radial Bearing Shaft Seals – AS and SA
AS and SA are radial oil seals for stainless steel bearing housings. They seal bearing housings against contaminants with long-lasting efficiency. There are two versions available, AS and SA. Each version has a specific design for specific applications.
The seals are made of nitrile rubber (NBR) which provides good resistance against mineral oils and greases, making them suitable for a wide range of standard industrial applications.
AS Seal
AS oil seals are designed with asymmetric lip angles. The angle α between the shaft and lip on the air side is larger than the angle β on the lubricant side. This geometry is designed to prevent contamination from entering the bearing housing while retaining lubricant inside. Normally, seals are designed with a small angle β on the lubricant side and a large angle α on the air side. This prevents lubricant from leaking out of the system. However, when grease is used, the difference in angles is less important and often reversed to provide better sealing against contaminants from outside. This is what we call the AS version.
The AS seal provides reliable sealing for bearing housings in standard to moderately contaminated environments, especially suitable for use in closed bearing assemblies such as AS / AS-VK assembly. Used on places with none abrasive surrounding. Just to close and become a maintenance free bearing unit sealed against contaminants.
Mounting tip
It is necessary that, if you do the initial greasing, to keep the cap a little bit open. To ensure that air can escape.
SA Seal
SA oil seals are designed with asymmetric lip angles as shown in the illustration. The angle α between the shaft and lip on the air side is smaller than the angle β on the lubricant side to prevent lubricant from leaking out of the system. When grease is used, the difference in angles is less important and often reversed to provide better sealing against contaminants from outside. We call this seal version SA. Leakage is less of a concern here due to the consistency of grease, which prevents excessive loss of lubricant. Therefore the main purpose of the grease seal is to keep contaminants out.
To improve bearing life by the correct use of bearing shaft seals, it is recommended to use an automatic lubricator or lubricate regularly. Only a small quantity of grease is necessary when slowly flushed into the bearing cavity to force dust and moisture away from the seal lips.
Note – SA Seal Is Not for Food Applications
The SA seal is not suitable for applications where high hygiene is demanded because the cavity in the lip can act as a chamber for collecting dirt. For high hygiene applications, use our CC design.
Not suitable for abrasive environments
The AS seal and, to a lesser extent, the SA seal are not suitable for applications where there is a risk of contamination from abrasive materials. For this type of application, use our CS design.
Grease Is a Great Help to Sealing Bearing Housings Against Contaminants
Grease can be a great help to sealing bearing housings against contaminants. The gaps between the lips of the centrifugal seal and the stator must be sealed to keep out dust and water. To improve bearing life for centrifugal bearing shaft seals, it is recommended to use an automatic lubricator or to lubricate regularly. Only a small quantity of grease is necessary when slowly flushed into the bearing cavity to force dust and moisture away from the working parts.
Examples of Grease Diagrams Using AS Bearing Shaft Seals
If the contamination is only on one side of the bearing unit, a seal combination can be chosen that is based on refilling the grease on this side. In this way, the contamination along with the grease shall flow away from the sealing lips. An example of such an assembly, a CS-AS combination, is shown in one of the illustrations with the path of the grease shown by the red arrows.



Important Information for Initial Greasing of Pressure-Tight Bearing Units
In some configurations, the bearing units from Extreme Bearing are bearing shaft seals pressure-tight. Therefore it is necessary to keep the cap a little bit open while you do the initial greasing. Otherwise problems like in the picture shown here can occur.
In addition, whenever it is necessary to add some more grease later, you should always take care not to create overpressure in the housing. The Extreme Bearing units are pressure-tight when used with the following configurations of seals: AS/AS, AS/VK, CL/CL and CL/VK.
ما الذي تقاومه هذه الأختام – NBR (أختام AS / SA / CS)
تعرض القائمة أدناه المواد الكيميائية والسوائل والغازات التي يقاومها بثبات عنصر الإحكام المصنوع من NBR (المطاط النيتريلي) في أختام AS و SA و CS. تعني العلامة في عمود درجة الحرارة أن الختم يصلح لهذا الوسيط عند تلك الدرجة. الخلايا الفارغة تعني أن الوسيط غير موصى به عند تلك الدرجة — اختر عندها ختمًا أعلى جودة (FKM أو سيليكون أو PTFE).
قيم إرشادية مبنية على جداول التوافق الصناعية (Parker O-Ring Handbook و Trelleborg و ERIKS). يتحمل المستخدم النهائي مسؤولية التحقق من الملاءمة لتطبيقه المحدد — التركيز والضغط والإجهاد الميكانيكي ومدة التعرض كلها مهمة. عند الشك، يرجى التواصل مع Extreme Bearing للحصول على توصية مخصصة.
| المادة الكيميائية | 20°C / 68°F | 60°C / 140°F | 100°C / 212°F |
|---|---|---|---|
| Formaldehyde (40%) | ✓ | ||
| Ascorbic حمض | ✓ | ✓ | |
| Citric حمض | ✓ | ✓ | |
| الأحماض الدهنية (>C6) | ✓ | ||
| Oxalic حمض | ✓ | ||
| Phthalic حمض | ✓ | ||
| Stearic حمض | ✓ | ✓ | |
| Tannic حمض (10%) | ✓ | ✓ | |
| Tartaric حمض | ✓ | ✓ | |
| Boric حمض | ✓ | ✓ | |
| Carbonic حمض | ✓ | ✓ | |
| Silicic حمض | ✓ | ||
| كبريتيتات | ✓ | ✓ | |
| Ammonia, مائي | ✓ | ||
| الصودا الكاوية والبوتاس | ✓ | ||
| Lime (CaO) | ✓ | ✓ | |
| Alum | ✓ | ✓ | ✓ |
| Aluminium كلوريد | ✓ | ✓ | |
| Aluminium كبريتات | ✓ | ✓ | |
| أمونيوم كلوريد | ✓ | ✓ | |
| Brines, مشبع | ✓ | ✓ | |
| Bromide (K) محلول | ✓ | ✓ | |
| Calcium كلوريد | ✓ | ✓ | |
| Chlorates of Na, K, Ba | ✓ | ✓ | |
| Chlorides of Na, K, Ba | ✓ | ✓ | ✓ |
| Copper salts (most) | ✓ | ✓ | |
| Ferric كلوريد | ✓ | ✓ | |
| Ferrous كبريتات | ✓ | ✓ | |
| Lead acetate | ✓ | ||
| Mercuric كلوريد | ✓ | ✓ | |
| Mercury | ✓ | ✓ | ✓ |
| Nickel salts | ✓ | ✓ | |
| نترات Na وK وNH3 | ✓ | ✓ | |
| نتريت (Na) | ✓ | ✓ | |
| Silver نترات | ✓ | ✓ | |
| صوديوم كربونات | ✓ | ✓ | |
| صوديوم silicate | ✓ | ✓ | |
| صوديوم كبريتيد | ✓ | ✓ | |
| Stannic كلوريد | ✓ | ||
| Sulphates (Na, K, Mg, Ca) | ✓ | ✓ | |
| Zinc كلوريد | ✓ | ✓ | |
| Cyclohexane | ✓ | ✓ | |
| Naptha | ✓ | ✓ | |
| Petroleum spirits | ✓ | ✓ | |
| Paraffin wax | ✓ | ✓ | |
| زيوت ديزل | ✓ | ✓ | |
| زيوت معدنية | ✓ | ✓ | |
| زيوت نباتية وحيوانية | ✓ | ✓ | |
| Alcohols | ✓ | ||
| Methanol | ✓ | ||
| Glycerine | ✓ | ✓ | |
| Glycols | ✓ | ✓ | |
| Glycol, ethylene | ✓ | ✓ | |
| Acetylene | ✓ | ✓ | |
| مبردات مفلورة | ✓ | ||
| Sulphur | ✓ | ✓ | |
| ماء مقطر | ✓ | ✓ | |
| ماء عسر منخفض | ✓ | ✓ | |
| ماء عسر | ✓ | ✓ | |
| مياه البحر | ✓ | ✓ | |
| Moist هواء | ✓ | ✓ | |
| Beer | ✓ | ✓ | |
| عصائر الفواكه | ✓ | ✓ | |
| Gelatine | ✓ | ✓ | |
| عصائر اللحوم | ✓ | ✓ | |
| Milk products | ✓ | ✓ | |
| Molasses | ✓ | ✓ | |
| Starch | ✓ | ✓ | |
| Sugar, syrups & jams | ✓ | ✓ | |
| Tallow | ✓ | ✓ | |
| Urea (30%) | ✓ | ✓ | |
| Yeast | ✓ | ✓ | |
| Detergents, synthetic | ✓ | ✓ | |
| Silicone fluids | ✓ | ✓ | |
| مواد مُبللة (<5%) | ✓ | ✓ | |
| Ethanol | ✓ | ||
| Isopropanol (IPA) | ✓ | ||
| Propylene glycol | ✓ | ✓ | |
| ماء/glycol coolant | ✓ | ✓ | |
| سائل هيدروليكي (HL, HLP, HM, معدني) | ✓ | ✓ | |
| سائل هيدروليكي HFA (زيت في ماء) | ✓ | ✓ | |
| سائل هيدروليكي HFC (ماء-جلايكول) | ✓ | ✓ | |
| سائل فرامل (DOT 3/4، جلايكول) | ✓ | ||
| بنزين / petrol | ✓ | ||
| Kerosene | ✓ | ✓ | |
| Jet وقود (JP-4/JP-5/JP-8) | ✓ | ✓ | |
| زيت تدفئة / وقود زيت | ✓ | ✓ | |
| LPG (propane, butane) | ✓ | ✓ | |
| AdBlue (urea محلول 32.5%) | ✓ | ✓ | |
| Transformer زيت | ✓ | ✓ | |
| Turbine زيت | ✓ | ✓ | |
| Gear زيت | ✓ | ✓ | |
| سائل ناقل حركة ATF | ✓ | ✓ | |
| شحم سيليكون | ✓ | ✓ | |
| شحم صابون الليثيوم | ✓ | ✓ | |
| مضغوط هواء, جاف | ✓ | ✓ | |
| Nitrogen (N2) | ✓ | ✓ | ✓ |
| Carbon dioxide (CO2) | ✓ | ✓ | |
| Hydrogen (H2) | ✓ | ✓ | |
| Helium (He) | ✓ | ✓ | ✓ |
| Argon (Ar) | ✓ | ✓ | ✓ |
| Ethylene (C2H4) | ✓ | ✓ | |
| Propylene (C3H6) | ✓ | ✓ | |
| Methane (CH4) | ✓ | ✓ | |
| غاز طبيعي | ✓ | ✓ | |
| Carbon monoxide (CO) | ✓ | ✓ | |
| مبرد R22 (HCFC) | ✓ | ||
| مبرد R134a (HFC) | ✓ | ✓ | |
| مبرد R1234yf (HFO) | ✓ | ✓ | |
| مبرد R717 (أمونيا) | ✓ | ||
| مبرد R744 (CO2) | ✓ | ✓ | |
| نبيذ | ✓ | ✓ | |
| قهوة / شاي | ✓ | ✓ | |
| عصير خضار | ✓ | ✓ | |
| منظف CIP قلوي (1-3%) | ✓ | ||
| Pentane | ✓ | ✓ | |
| Hexane | ✓ | ✓ | |
| Heptane | ✓ | ✓ | |
| Octane | ✓ | ✓ | |
| Isobutylene | ✓ | ||
| Butanol (n-butanol) | ✓ | ||
| n-Propanol | ✓ | ||
| Oleic حمض | ✓ | ||
| Palmitic حمض | ✓ | ||
| Adipic حمض | ✓ | ✓ | |
| Lauric حمض | ✓ | ||
| أمونيوم كبريتات | ✓ | ✓ | |
| أمونيوم نترات | ✓ | ✓ | |
| Copper كبريتات | ✓ | ✓ | |
| Zinc كبريتات | ✓ | ✓ | |
| Magnesium كبريتات | ✓ | ✓ | |
| Magnesium كلوريد | ✓ | ✓ | |
| Barium كلوريد | ✓ | ✓ | |
| بوتاسيوم كلوريد | ✓ | ✓ | ✓ |
| صوديوم thiosulphate | ✓ | ✓ | |
| مبرد R32 (HFC) | ✓ | ✓ | |
| مبرد R410A (خليط HFC) | ✓ | ✓ | |
| مبرد R454B (خليط HFO) | ✓ | ✓ | |
| مبرد R1234ze (HFO) | ✓ | ✓ | |
| مبرد R290 (بروبان) | ✓ | ✓ | |
| مبرد R600a (أيزوبيوتان) | ✓ | ✓ | |
| Sulphur hexafluoride (SF6) | ✓ | ✓ | |
| Nitrous oxide (N2O) | ✓ | ✓ | |
| Olive زيت | ✓ | ✓ | |
| Soybean زيت | ✓ | ✓ | |
| Palm زيت | ✓ | ✓ | |
| Rapeseed (canola) زيت | ✓ | ✓ | |
| Fish زيت | ✓ | ✓ | |
| زبدة | ✓ | ✓ | |
| Cheese curds / whey | ✓ | ✓ | |
| Eggs (raw / سائل) | ✓ | ✓ | |
| خردل | ✓ | ✓ | |
| سائل sugar / glucose syrup | ✓ | ✓ | |
| Quaternary أمونيوم compounds (QACs) | ✓ | ||
| Chlorhexidine محلول | ✓ | ✓ | |
| زيت قطع (مستحلب قابل للذوبان في الماء) | ✓ | ✓ | |
| زيت قطع (نقي، معدني) | ✓ | ✓ | |
| HVO renewable ديزل | ✓ | ✓ | |
| Marine heavy وقود زيت (HFO) | ✓ | ||
| طين حفر (أساس مائي) | ✓ | ||
| طين حفر (أساس زيتي) | ✓ | ✓ | |
| ملاط إسمنتي | ✓ | ||
| ملاط رماد متطاير | ✓ | ✓ | |
| Cyanide محلول (gold mining, NaCN) | ✓ |
Service instruction
Please inform your maintenance crew about this special service operating instruction. It could be helpful to dismount the grease nipples and exchange them with a standard stainless screw, so it will be impossible to make mistakes.