What are Oil Seals and how should they be ordered?

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Figure 1: Types of sealing devices
Floating oil seals are essential components used in various industries to prevent leakage of oil and other fluids. These seals are designed to float on the surface of the oil, creating a barrier that keeps the oil contained within a system. They are commonly used in gearboxes, hydraulic systems, and other machinery where the potential for oil leakage is a concern.

Replacing a rocker or cam-cover gasket


GVST
Polyacrylate Oil Seals - Mostly selected for automotive and transmission uses, polyacrylate seals are able to withstand fuel, oil, ozone, sunlight and weather when used. With cars exposed to all these different fluids and elements, they are the perfect choice. However, they should not be used in low temperatures, as their flexibility weakens when cold.
Areas of application of this rubber are suggested by its outstanding temperature resistance (-55 °C to +200 °C), although this must not be applied to hot water or steam. Although silicone rubber almost matches NBR in oil resistance, it does not match the latter's physical and mechanical properties.

A synthetic rubber used in gaskets, o rings, lip seals, and other moulded devices, Viton offers sealing properties for a range of oil-based applications. Viton with high fluorine grades will also produce excellent resistance to swell, especially in oxygenated fuel and high-octane blends.
Fluoro natural rubber (FPM - FKM - Viton)
There are various sizes of industrial and ordinary oil seals, ranging from 0 to 33cm (13in). These varieties are also designed for different temperatures. As long as your seal matches the original equipment it’s intended for, you can be sure your machine will perform at its best.
How are they used?
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.