Parker Prädifa offers a large number of combined pneumatic seals and wipers for the open groove of the EU system. By installing the right type of seal, a wide range of applications can be covered with just one cylinder. Another advantage - thanks to the open groove, the seals are very easy to install and remove.
The available materials range from NBR, HNBR to FKM and TPU through to PA-based materials -
If extreme resistances, dry-running properties, or stick-slip-free operation are required, PTFE compounds or UHMW PE will be used.
Further materials can be provided at the customer’s request.
The wide range of available solutions can cover temperatures from -200°C to 260°C at a maximum speed of 1m/s.
Modified wiper geometries are available to provide protection against ambient influences. Without additional expense to the customer, they prevent the ingress of liquids or fluids, viscous media, or slight deposits into the cylinder.
For anti-torsion piston rods with two flat sides, special seals are available.
In case of harsh conditions, the use of split versions is recommended. This means that the material can be optimally adapted to the function of the seal and the wiper lip.
For hygienically sensitive applications in the food processing industry or life sciences, wiper lips without undercuts or indentations are available. If, in addition, a bactericidal or fungicidal effect is required, the seals can be made from a special TPU material with a formulation that counteracts the formation of cultures on the sealing surfaces over a long period of time. This also effectively stops the decomposition of the seal material.
Where elastomers and plastics no longer achieve a sufficient wiping effect metallic wipers are used. Thermal caking, ice, resins, slag, textile or paper dust, as well as metal spray, are reliably wiped off to keep the piston rod clean. This system can be snapped into the normal groove without any additional effort as well.
The seals can be very easily installed and removed through the open groove. If the system seal has to be replaced this can – depending on the seal type – typically be done without disassembling the cylinder and while the piston rod remains installed.
The housing, which is identical for all sealing elements of the EU system, allows easy refitting of the pneumatic cylinders for different requirements. The seals are installed into the open housings by means of a handling tool.
Article contributed by Roland Schüßler senior application engineer Prädifa Technology Division
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