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 and SA radial bearing shaft seals – stainless steel bearing housing

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.

AS seal grease direction illustration

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.

SA seal grease direction illustration
Dirt build-up in bearing housing seal cavity

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.

Conveyor belt in seawater environment with pillow block bearing and single-point greaser

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.

Example of damage from incorrect greasing of a pressure-tight bearing unit

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.