grp sectional tank
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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.
Regardless of how many (or how few) miles you have on your vehicle, regularly scheduled oil changes are critical for keeping your car running newer, longer. When you head in for your next oil change at a nearby Firestone Complete Auto Care, ask your technician about a high mileage oil change, especially if you’ve observed oil stains in your driveway or heard engine rattling. A high mileage oil change could help your car hit its next big milestone!
However, rubber-cased seals do have limitations. For example, during installation, shear stresses can build up between the seal and housing wall, causing the seal to release itself.
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4. Fluroelastomer also popularly known as Viton. – The high temperature resistant material used in places where temperature is more than 120 Degree Celcius.
The rubber material used in the oil seal should be selected based on the operational temperature and substance to be sealed.
Table 5 lists the major rubber materials along with their operational temperature ranges.
Note that it is necessary to check the compatibility with fluids.
<N.B.>
Extreme pressure additives are compounds added to the lubricant. They are activated by heat and chemically react against rubber, which deteriorates rubber properties. For this reason, it is necessary to check for compatibility with rubber materials.
Even though it’s better than other materials in terms of toughness and wear time, it is preferably used in dry-running applications. The salient demerit of this material is its cost.
Case study 1: Volkswagen
• Super helix seal