Obtaining adequate adhesion of fluoroelastomer compounds to metal inserts is a major consideration in fabrication of shaft seals. Adhesive systems worked out for bisphenol-cured VDF/HFP/TFE elastomers often do not perform adequately for peroxide-curable fluoroelastomers and more base-resistant polymers that contain little or no VDF. The trend toward use of more resistant fluoroelastomers in shaft seals has necessitated considerable effort on compounding and adhesive system development to get adequate bonding of the new materials. Silane-type primers are often used to coat metal inserts; these contain residual active groups such as amine functions that interact with the fluoroelastomer compound to attain good adhesion, especially for VDF/HFP/TFE elastomers. Other adhesive systems, using epoxy compounds or tie-coats, may be necessary for difficult bonding situations.3
- Despite their prevalence, the importance of rubber gaskets is often overlooked until a failure occurs. A faulty gasket can lead to leaks, which in turn can cause damage to equipment, loss of valuable resources, and potential safety hazards. Hence, choosing the right type of gasket for the job is crucial, and regular inspection and maintenance are vital to prevent issues before they become problems.
DIN
Proper preparation is crucial for successful oil seal installation. Ensuring that the seal, shaft, and bore are correctly prepared and aligned prevents seal failure, leakage, and premature wear of the components.
Leather is probably the oldest of the lip materials still in common use, but the move towards mass production methods has seen a massive increase in the development of synthetic rubbers which lend themselves to accurate and repeatable injection and compression moulding. Nitrile (NBR) is still by far the most common elastomer for “normal” use, whilst Viton® (FKM/FPM) is rapidly replacing Polyacrylate (ACM) and Silicone (VMQ) for high-temperature applications. Viton® also has high resistance to abrasion and chemical attack making it a preferred elastomer. Recent developments in the use of PTFE for Rotary shaft seals has caused widespread interest particularly for high-speed shaft rotation or poor lubrication applications.



Table 6: Selection of metal case and spring materials
-80 °C to + 200 °C
Storage and Handling
The material of the sealing lip is chosen according to the liquid to be sealed and the rotational speed. For larger shafts, an NBR sealing lip can cope with surface speeds of up to 10-12 m/s, while an FKM lip is suitable for speeds of up to 35-38 m/s.
Stainless steel sheet
(JIS* SUS304)

