BECA 021

Dimensions

Installation drawing

Materials

Profiled seal

NBR (Nitrile Butadiene Rubber)

Nitrile rubber (NBR) is the general term for acrylonitrile-butadiene copolymer. The ACN content can vary between 18% and 50%. While the acrylonitrile content is important, the resistance to oil and fuel is more so. Conversely, the elasticity and compression set are not as good. The NBR has good mechanical properties and good wear resistance. However, its resistance to atmospheric agents and the ozone is relatively low.

FKM (fluorinated rubber)

Depending on their structure and fluorine content, the chemical resistance and resistance to the cold in fluororubbers can vary. This FKM-based rubber is very often used for high-temperature hydraulics and pneumatics, for industrial valves, injection/fuel systems, motor seals and high-vacuum systems.

EPDM (Ethylene Propylene Diene Monomer rubber)

As an Ethylene Propylene Diene Monomer copolymer, EPDM is commonly used for hot water taps, cooling systems, brake systems, dishwashers and washing machines.

HNBR (Hydrogenated Nitrile Butadiene Rubber)

This HNBR-based rubber is obtained through selective hydrogenation of the NBR's butadiene groups. It is commonly used for power-assisted steering and for air conditioning.

VMQ (silicone rubber: methyl vinyl polysiloxane)

This FVMQ-based rubber is very often used in fuel systems.

FVMQ (fluorosilicone rubber)

The FVMQ has mechanical and physical properties that are very similar to those of the VMQ. However, the FVMQ offers better resistance to fuels and mineral oils. However, resistance to hot air is not as good as that of the VMQ.

The table below gives an overview of the physical, chemical and mechanical characteristics for each of the materials.

1. Excellent properties 2. Good properties 3. Average properties 4. Poor properties

Back-up ring

Polyoxymethylene - POM

Polyoxymethylene (POM or polyacetal) belongs to the thermoplastics, which have a number of advantages - strong mechanical resistance, good creep strength, high resistance to shocks, particularly at low temperatures, good wear resistance, good sliding coefficient, excellent machinability and good dielectric properties. The low water absorption coefficient, unlike polyamide (PA), also gives this material an excellent dimensional stability.

Filled PTFE

PTFE is a thermoplastic polymer made of tetrafluoroethylene with exceptional properties - very low friction coefficient (adhesive friction and sliding friction are almost equal), physiologically safe for temperatures up to +260°C, excellent electrical insulation properties, and excellent chemical compatibility with the majority of fluids. On the other hand, as this material is plastic and not elastic, so it cannot easily replace rubber bases.

Chemical compatibility

A "Chemical compatibility guide" catalogue can be downloaded from the Documentation section. You can also use our online "Chemical compatibility" tool free of charge.

These two tools give you the option of measuring the behaviour of our materials that come into contact with the majority of existing fluids. The data displayed is the result of rigorous testing of the ambient temperature and in consultation with previous publications. Test results are not fully representative due to the specific features of your application. The tests performed actually do not consider additives and impurities that may exist under the actual conditions of use, nor the potential elevation of temperatures. Other parameters can also alter the behaviour of our materials, such as the hardness, persistence, abrasion, etc. We therefore recommend performing your own tests to verify the compatibility of our materials according to your specific application. Our technical team can provide you with any additional information.

Technical data

Groove widths and extrusion gaps

Tolerances on the rod diameters and groove diameters

Surface roughness

Chamfers and radius