Wipers

Description
Wiper rings suitable for use in hydraulic and pneumatic systems.

Hardness
The hardness of the Wipers is usually in Shore A or IRHD. The standard hardness is 90Sh (Shore) for NBR, for the TPU material it is 95 Sh.

Function
Wiper seals maintain sealing contact to the piston rod when the equipment is stationary (static, no reciprocating motion of rod) and in use (dynamic, reciprocating rod), whereas the tolerance for the rod diameter d is determined by the rod seal. Without a wiper seal, the retracting piston rod could transport contaminants into the cylinder. The outside static sealing of the wiper seal within the housing is also important to avoid moisture or particles from entering around the outside of the wiper seal.

Types 

• Single acting - It is pressed against the rod, dirt is wiped from the surface by the action of the rod as it retracts.
• Double acting - It provides a double function wiping the dirt from the rod and retaining the residue oil film with the second lip. 

Materials
NBR -  Good chemical resistance to mineral oils and greases, hydraulic oils H, HL, HLP, non-inflammable hydraulic pressure fluids HFA, HFB, HFC to approx. +50°C and water to max. +80°C 
PTFE – Nearly universal chemical resistance (aggressive acids, bases, alcohols and oils). Resistant to high and extremely low temperatures .
TPU – high abrasion resistance, low-temperature performance, high shear strength, high elasticity, oil and grease resistance.
Steel  – acc. DIN EN 10139 . Steel is vulcanizate to seal part .