The rider split or wear ring is part of all piston designs where there is no lubrication or the
possibility of loss of lubrication exists during operation. New process compressors have rider
rings included whether the compressor is lubricated or non-lubricated. The rider supports the
weight of the piston and prevents contact with the cylinder wall. It is designed taking into
consideration the weight of the piston and rod, the physical properties of the ring material, the
operating conditions and the desired ring life. AAVOLYN engineers have considerable
experience in designing PTFE rider rings for all pressures, temperatures and gases. The
Type 430 split rider ring is recommended unless the ring travels out into the counter bore
area. Side and face grooves can be added to ensure the rider ring does not act as a piston
ring. The large surface area would generate significant frictional heat. Therefore grooves are
necessary to prevent the ring from sealing. The split rider is available in step, angle or butt
cut design.
