PTFE-Seals

General

A classic solution for the low-friction sealing of pistons and piston rods in a system involves the use of a PTFE seal with a preload rubber laminate. This form of compact design has proven highly successful in a wide range of different applications over many years.

The sealing elements have a decisive influence on the design, function and service lifetime of hydraulic cylinders. The various material combinations possible within the PTFE segment offer high functional reliability and durability adapted to each requirements profile. Owing to the special material properties inherent in PTFE, high abrasion resistance, shape and dimensional stability and also outstanding sliding properties are ensured. The material also offers very good thermal and chemical resistance values.

Standard-PTFE-Comounds

PTFE-Compounds
The many different PTFE compounds offer a widely dispersed application spectrum in hydraulics and pneumatics. Generally, these materials exhibit very good sliding properties, high shape and dimensional stability values and are characterised by good chemical and thermal resistances. Compounds not specifically mentioned, and also modified compounds, can likewise be provided with individualised adaptation to each requirements profile.

PTFE-Bronze
This is one of the preferred material combinations for medium to heavy-duty hydraulic applications. The material exhibits high compressive strength, and good sliding and wearing properties. It is extremely extrusion-resistant and offers optimum thermal conductivity.

PTFE-Carbon
Recommended for medium-duty applications and preferred in conjunction with water and water-oil emulsions. The material exhibits high abrasion resistance and good chemical resistance. Dry-running is possible; suitable for soft/yielding mating surfaces.

PTFE-Fibreglass

Recommended for medium-duty applications in both hydraulics and industry in general. PTFE-fibreglass seals exhibit high abrasion resistance, good chemical resistance and are very extrusion-resistant.

PTFE-virginal
Recommended for light-duty mechanical-contact applications, and the preferred alternative in the food, chemical and pharmaceutical industry. Very good thermal and chemical resistance values.

Selection

The variety of deployment scenarios and thus operational conditions call for a respective dimensioning of the sealing element. The selection of materials and considering all required parameters for influencing the sealing behaviour of a seal and its limit values result in the requirement of a functional overall solution.

Standard design of the multi-part sealing element, for piston and bar for back and forth deployments, is PTFE bronze along with an O-ring of NBR 70 Shore for the pressure element.