DICHTA® END COVERS are made of metal with a nitrile rubber cover on the outside and are typically mounted in applications where the rotary shaft does not pass through the housing wall of the bore.
In addition, end caps protect the bearings. The covers are designed to fit into the bore with the same tolerance as the OD of an oil seal.
Upon request, further materials and sizes may be supplied.
This elastomer is a copolymer of butadiene and acrylonitrile and is used for the majority of conventional fluid sealing application.
STANDARD COLOUR:
ADVANTAGES
good resistance to mineral oil and grease
good resistance to water and radiator fluid
LIMITATIONS
poor resistance to high-alloyed hypoid oil
poor resistance to ozone, weathering and sunlight
not resistant to automotive brake fluid (glycol based)
poor resistance to polar fluids (ketones, ethers, esters)
poor resistance to chlorinated hydrocarbons (carbon tetrachloride, trichloroethylene)
poor resistance to aromatic solvents
Hydrogenated Nitrile Butadiene Rubber (HNBR)
STANDARD COLOUR:
ADVANTAGES
High resistance to oils and greases
Good resistance to mineral and hydraulic oils
Good resistance to acids and bases diluted
Excellent resistance to ageing, ozone and weathering
LIMITATIONS
Poor resistance to acids and bases concentrated
Poor resistance to aromatic and polar solvents
Elastomeric compounds (FFKM)
FFKM materials are elastomeric compounds designed with high fluorine content to offer extreme chemical resistance, similar to PTFE, and at the same time the elastic qualities of an elastomer.
ADVANTAGES
Excellent heat resistance
Excellent chemical resistance
Good mechanical properties
Low gas permeability
Excellent weather ability and ozone resistance
Polyethylene (UHMW-PE)
UHMW-PE polyethylene is a pressed technopolymer with very high molecular density. Compared to polyethylene with lower densities it has better mechanical characteristics, better resistance to wear and better smoothness having a lower coefficient of friction.
It is a very versatile plastic material and used in very many fields, offering durability to wear and good smoothness characteristics.
ADVANTAGES
Excellent resistance to very low operating temperatures
Good insulation properties
Excellent workability with low specific weight
Good smoothness
Physiologically harmless
Insoluble
Good impact resistance
Resistance to chemical agents
Suitable for contact with food
Polyamides (PA)
Polyamides are the most widely used thermoplastics and have the advantage of having excellent mechanical properties which remain constant even at high and low temperatures and a low coefficient of friction.
They have excellent wear and abrasion resistance and are also resistant to various chemical and atmospheric agents.
Being a hygroscopic material, i.e. it has a high humidity absorption, it is not suitable for applications involving contact with water or when demanding tolerances are to be maintained, especially in humid environments (for this reason PA is not used in contact with food).
ADVANTAGES
Good resistance to breaking, traction, compression and impact
Good resistance to aging and atmospheric agents
High mechanical strength even at high temperatures
Low coefficient of friction and abrasion
Excellent resistance to machine oils and greases
Zero resistance to concentrated acids
High humidity absorption (not suitable in the electrical sector)
High resistance to alkalis, inorganic compounds and solvents
Polyoxymethylene (POM)
Polyoxymethylene (POM, commonly known as Acetal Resin) is a semi-crystalline thermoplastic technopolymer popular for its excellent mechanical characteristics. It is used for the production of precision parts that require high rigidity, as an alternative solution to replace some metals such as steel, brass, aluminium. It has a low coefficient of friction and great dimensional stability, excellent sliding properties, resistance to wear and reduced moisture absorption.
ADVANTAGES
High strength & rigidity
Excellent creep resistance
Outstanding wear resistance
Good hydrolytic stability
Good resistance to stress cracking
Low friction
Very good machinability
PEEK
PEEK is a semi-crystalline thermoplastic known chemically as polyetheretherketone with excellent chemical resistance, very good mechanical characteristics, low permeability and with the best tensile strength coefficient of plastics. This material can be filled with glass fibre, carbon, PTFE, graphite and other components.
ADVANTAGES
Excellent dimensional stability
High mechanical strength, stiffness and hardness
Low flammability
Excellent ratio between stiffness, strength and resilience
Self-extinguishing
Very low flue gas density
Resistant to high and low temperatures
Excellent resistance to abrasion and wear
Low coefficient of linear expansion
Modified PTFE (MPTFE)
Modified PTFE (or MPTFE) is a further development of regular PTFE with a different chemical structure, reducing significantly its molecular weight. This compound presents a high quality and poreless character.
ADVANTAGES
Substantial reduction of deformation under load
Much higher elongations and breaking loads
Less permeability given by a denser structure of the polymer
Smoother surfaces
Improved stress recovery even at high temperatures
Higher transparency
Material - PTFE
Upon request we can supply the following material options:
Virgin PTFE
PTFE + Glass MoS2
PTFE + BaSo4 (barium sulphate – FDA)
PTFE + Ekonol (FDA)
PTFE + glass fiber (FDA)
PTFE + hollow glass microspheres (FDA)
PTFE + Carbographite
Material - PU
STANDARD COLOUR:
ADVANTAGES
FDA compliant
Excellent wear resistance
Excellent abrasion resistance
Excellent for dry applications
Low risk of deformation
Low coefficient of friction
LIMITATIONS
Poor chemical resistance
Poor dimensional stability in temperature
Material - FPM
It has good chemical resistance and is recommended for high temperature applications.
STANDARD COLOUR:
ADVANTAGES
excellent resistance to mineral oil and above all high-alloyed hypoid oils
excellent acid resistance
good resistance to aromatic and chlorinated hydrocarbons
excellent resistance to ageing, ozone and weathering
LIMITATIONS
limited cold flexibility
poor resistance to polar fluids (ketones, ethers, esters)
Material - MVQ
STANDARD COLOUR:
ADVANTAGES
retains flexibility down to very low temperatures
withstands continuous heating at high temperatures without hardening
resistant to mineral oil and greases
excellent resistance to ageing, weathering and ozone
good chemical resistance to alkalis
LIMITATIONS
not recommended for use with hydrocarbons such as petrols and paraffin, and lighter mineral oil or steam over 3.5 bar
not resistant to hot water, acids and non-mineral automotive brake fluids
poor wear resistance
Material - EPDM
STANDARD COLOUR:
ADVANTAGES
excellent resistance to ageing, weathering and ozone
good resistance to water and steam
good resistance to automotive brake fluid (glycol based)
good resistance to polar fluids
LIMITATIONS
poor resistance to mineral oil and grease
Material - ACM
STANDARD COLOUR:
ADVANTAGES
good resistance to oils and fuels
good resistance to ozone and weathering
LIMITATIONS
not resistant to water and water solutions
poor resistance to polar fluids (ketones, ethers, esters)
poor resistance to chlorinated hydrocarbons (carbon tetrachloride, trichloroethylene)
poor resistance to aromatic solvents
limited cold flexibility
poor wear resistance
Material - CR
STANDARD COLOUR:
ADVANTAGES
excellent resistance to ageing, weathering and ozone
moderate resistance to mineral oils and greases
LIMITATIONS
tends to harden or stiffen at low temperatures
not resistance to non-mineral automotive brake fluids