Compounds:
Depending on medium, running surface and types of mechanical stress. Subject to ultimate selection by our application engineers.

PTFE Piston Seals Types
Straight joint	Piston rings with a straight-joint design are used for sealing pressure differences above 15 bar. Leakage with this joint will be slightly higher than with chamfered or scarf joint designs. Due to the high speeds at which today’s compressors usually operate, the loss of leakage gas has only a minimal impact on condenser performance. The amount of leakage gas is negligible.
Chamfered joint	Piston rings with chamfered or scarf joints are also used for sealing pressure differences above 15 bar. Sealing performance of this version is slightly higher during the break-in period than that of straight-joint piston rings.
Lap joint	Lap joints produce a favorable sealing effect. For this reason, it is the preferred design for sealing gases with a light specific weight. Due to bending stress and the resulting risk of breakage at the lap joints, piston seals with these joints should only be used in compressors with maximum pressure differences of 15 bar.
Gas-tight joint	“Gas-tight“ piston rings offer optimum sealing performance. Because of the special joint design of this split ring, leakage is reduced to a minimum. As with lap joint designs the maximum pressure difference is limited to 15 bar. With regard to assembly, please note that the piston ring only achieves a good sealing effect in one direction of thrust.
PTFE Piston Guide Rings Types
Straight joint	Guide rings in piston condensers serve to prevent contact between the piston and the cylinder wall in order to avoid resulting damage to these parts. Guide rings usually have a straight or chamfered joint design, with straight joints being the most commonly used version. Guide rings with chamfered or scarf joints have the advantage of the joint traveling over the entire contact surface of the cylinder, thus producing no “marks” on the contact surface like the directly impacting straight gaps. Installation of guide rings with straight or chamfered joints is only possible if the guide rings do not travel across the valve nests inside the cylinder with more than 1/3 of their widths. In case guide rings travel across several valve nests, single-part press-fit guide rings are used. Depending on the type of application, guide rings with axial and/or radial load relief grooves may be used as well.
Chamfered gap
Non-split version
Shouldered design with straight gap