Bellows with round folds, Type FR

The bellows type FR with round folds are manufactured by machine cutting. It is characterized by a high stiffness and permits only short strokes. This makes it especially well-suited for medium pressure stresses.

The advantages of this bellows type are the stable walls and very good cleanability. Horizontal and vertical installation are both possible. Very frequent connection types are flange connections, screw threads and ball/ball sockets. Further connections with customer-specified adaptions are also possible.

Areas of applications are expansion and vibration compensation between pipelines, protection of spindles and rods in corrosive atmospheres and in fluid streams. This bellows type is therefore used mainly in chemical and process engineering, in mechanical engineering and in the food and pharmaceutical industry. The operating temperature ranges between -120 °C to +150 °C.

Examples of structural forms 

Round folds, two-sided flange connection

ptfe faltenbalg runde falten produkt bild 01.

Round / angular folds, First side: Flange connectionOther side: TriClamp connection

ptfe faltenbalg runde falten produkt bild 02.

Materials overview

MaterialsTypical propertiesOperating conditions
(PTFE pure)
low gas permeability, universal chemical resistance, good reverse bending strengtstandard material, for food environments
(PTFE modified)
very low gas permeability, universal chemical resistancefor enhanced requirements on gas tightness and surface finish
(PTFE modified)
very low gas permeability, universal chemical resistancefor enhanced requirements on reverse bending strength
PTFE conductivestatic dissipative propertiesfor ATEX requirements (ex areas), restricted reverse bending strength

Note: The application limits specified are dependent on one another and must not occur at the same time.

Application limits

Pressure: 0,25 to 5 bar (abs.)

Temperature: -120 °C to +150 °C


Further customer-specific adaptions are possible.

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