Definition - What does Wiper Seal mean?
A Wiper Seal is an axial seal that is installed on the external side of a cylinder head to prevent fluid contaminants and dirt particles from entering the reciprocating shaft mechanism. If the dirt particles are not prevented from entering the system, especially in hydraulic and pneumatic systems, they can cause damage to the system during stroke movement. The seal allows a reciprocating shaft to pass through the inner bore of the seal.
Petropedia explains Wiper Seal
Reciprocating systems such as hydraulic and pneumatic systems are used in a wide range of applications and operate in different environments which have a lot of contaminants and dirt particles like dust, water, mud etc. If the contaminants enter the system they can cause severe damage to the wear rings, seals and other internal sealing components. Wiper seals are fitted onto external side of the cylinder head on the piston rod to prevent these contaminants from entering the pneumatic system, piston-cylinder assembly and hydraulic system.
They are available in wide range of materials like Poly-tetra-fluoro-ethylene (PTFE) based material, elastomer, polyurethane etc.