draught excluder for bottom of front door

There is a British Standard laid down for the control of synthetic rubbers. BS 3574 (1989) helps to determine shelf life – for instance, Nitrile (NBR) and Polyacrylic (ACM) are Group ‘B’ rubbers and have a 7-year life, whilst Silicone (VMQ) and Fluoroelastomers (Viton®) are Group ‘C’ rubbers and have a 10-year shelf life. PTFE and Leather do not come into this category but like the others should be kept in the original packing for as long as possible away from direct light, dust, and humidity. Ozone, which can also be produced by battery-driven forklift trucks has a very bad effect on synthetic rubbers. Finally, protect the sealing lip – DO NOT hang the seals on nails, wire etc.

Nitrile Butadiene Rubber (NBR, nitrile)

• More compact thanks to the thin plate (uses a high-strength steel plate)

PTFE Oil Seals - A relatively new and exciting oil seal, the use of polytetrafluoroethylene means that they can withstand dry or unlubricated operations. With a massive thermal range of  -130ºC to +200ºC and a strong resistance to chemicals, they are considered to be the future of rotary shaft seals.

Valve cover gaskets and head gaskets play pivotal roles in maintaining the proper functioning of the engine. The valve cover gasket prevents oil leaks and contaminants from compromising the lubrication and performance of the engine, while the head gasket ensures the proper sealing of the combustion chamber, allowing for efficient fuel combustion and preventing the mixing of oil and coolant. Both gaskets are critical for the overall efficiency, performance, and reliability of the engine.

The seal shown in Fig. 14.2 is a relatively simple design; most automotive seals are more complex. Dust lips are often used to keep outside contaminants away from the oil lip seals; such seals thus have undercuts that make demolding more difficult. Fluoroelastomer compounds used for such undercut shapes must have reasonably high elongation at break at molding temperatures to avoid tearing the part during demolding. The metal insert is often U-shaped, and stock may be molded to form a thin layer over the outside of the insert. Since both compression and injection molding methods are used, suppliers of fluoroelastomers for shaft-seal applications often must provide different versions of the same polymer composition-medium to high viscosity for compression molding, and low to medium viscosity for injection molding. Different precompounds may be necessary to accommodate relatively long compression-molding times at low temperature and very short injection-molding times at high temperature.

What is an oil seal and how does it work?

6.  AMOUNT OF LUBRICANT: Seals perform better when lubricated but some machines will go through some dry spells. When this occurs using a leather or PTFE seal will be more beneficial as those type of seals can operate with less lubrication.

EPDM

First, an elastomer, most often nitrile, is vulcanised to a metal ring. This creates a stiffening effect that includes a specialised metal tension spring directly behind the sealing lip, keeping the oil seal firmly in place against the moving part.