Standard Seal Materials

Standard cylinders include seals of Buna-N, Polyurethane, and Teflon with the seal compound and location of use dependent on the design purpose of each model.

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Standard Cylinder Seals (Buna-N and Polyurethane):

Seals of Buna-N are predominant as they are used for stat- ic seals in all cylinders to prevent leakage between non- moving surfaces, and as dynamic rod or piston seals in other models. Seals of internally lubricated Polyurethane are also used as rod and piston seals with the material selected for use based on its performance characteristics and the application requirements. Teflon is used to seal the Cushion Adjusting Screw and Ball Check assemblies and for Piston Seals and Back Up Washers for certain seals in units suitable for high pressure service. The seal material specifications for any particular cylinder can be determined by referring to the “Design Feature” information given for available models.

Seals of standard cylinders are compatible with the following types of operating media:

• Air • Petroleum oils and fluids • Water soluble oil (to + 150oF Max.) • Water Glycol fluids (to + 150oF Max.) • Water/Oil Emulsions (to + 150oF Max.)

Buna-N material is suitable for use within a temperature range of -40oF to +250oF. Polyurethane may be used from - 65oF to +200oF. Teflon is unaffected by extreme tempera- tures and is not a factor in limiting service conditions.

Cylinder operation is not suggested near either end of the seal temperature range. Standard models are recommended for use at temperatures from -20oF to +180oF (-29oC to +83oC). When the operating fluid contains water, the maximum operating temperature should not exceed +150oF due to adverse effects of hot water on seals of Polyurethane.
Alternate seal materials are available upon request for use with other types of operating fluid or higher temperature requirements.