Characteristics and performance

The Hallite 780 double-acting piston seal in a robust five part assembly is designed specifically for one piece pistons in a wide range of medium duty applications. The seal is also suitable for two piece pistons.

Comprised of a nitrile rubber sealing element, two split support rings, and two split L-shaped bearings located either side of the seal, the well proven nitrile rubber sealing element is designed to be extremely wear resistant with multi-lips for efficient dynamic sealing with minimal low pressure friction and, when pressurized, will be protected from extrusion damage by the extending lips of the support rings.

The support ring is manufactured from a tough, flexible, wear resistant thermoplastic polyester elastomer (TPE) and scarf cut for assembly.

Both the L-shaped bearings and support rings are grooved to ensure that the fluid pressure properly energises the sealing element and to prevent the possibility of any pressure trapping within the seal assembly.

Product details

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Max pressure *

400 Bar

Temp range


Max speed


* Max pressure stated is dependant on the material variant selected. Please consult the datasheet for further information.

  • Recomended
  • Possible
  • Not suitable

* For fluid types marked as possible, please call our team of experts on +44 208 941 2244 to talk through your requirements and determine if this seal is the most suitable for your needs.

 Dynamic applicationStatic application
Fluids based on mineral oil  
Waterbased fluids  
HFA (5/95)PossiblePossible
HFB (60/40 invert emulsion)PossiblePossible
HFC (water glycol)Not suitableNot suitable
Other fluid types  
Air/NitrogenNot suitablePossible
HFD (Phosphate ester ARYL Type)Not suitableNot suitable
Synthetic esters (HEES, HFDU)PossiblePossible