Types of Seals Used in Hydraulic Cylinders

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Types of Seals Used in Hydraulic Cylinders

• Austin Seal CO

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• Hydraulic cylinders are widely used in a variety
  of machines because of their functionality. They
  are popular because of their performance in
  different situations and applications every day.
  From engines of heavy trucks to utility vehicles,
  hydraulic cylinders are popular for all kinds of
  motors because of their efficiency and
  performance.
• Talking about the performance of hydraulic
  cylinders, there is a complicated system which
  keeps the cylinder in motion. Two types of seals
  are required to keep the pressurized fluids
  contained in a hydraulic cylinder system. These
  two seals are high-performance seals are broadly
  categorized as static seals and dynamic seals
  (supported by guide rings), which are assembled
  in a complex configuration. In this article, we
  shall examine these categories of seals in
  detail.

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Static Seal

• A static seal does not move when subjected to
  pressure. It comprises of O-rings, gaskets,
  D-rings, cover seals, and back-up rings. O-rings
  are the simplest example of a static seal, which
  are highly popular too. They are available in a
  variety of sizes, and because of their shape they
  are considered versatile for sealing. O-rings
  create a perfect barrier between two surfaces,
  when placed into the cylinder housing and
  squeezed by a casing. O-rings are commonly used
  for their ability to endure extreme pressures,
  even over 1500 p.s.i. Combined with back up
  rings, O-rings offer great functionality. O-rings
  in nitrile rubber (NBR), fluoro rubber (FKM) and
  ethylene propylene diene (EPDM) are highly
  popular for use in a wide range of mineral oils,
  water -based fluids, water and air. Polyurethane
  (TPU), silicone and other such compounds are
  useful in a static environment.

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Dynamic Seal

• As opposed to static seal, a dynamic seal does
  not remain in one position when it is subjected
  to pressure. Under pressure, a dynamic seal
  exhibits axial and/or radial movement.
• Common examples of dynamic seals are rod and
  piston seals, oil seals, rotating seals, and
  wipers/scrapers. Although pistons undergo
  movement because of pressure exerted on them,
  they create a barrier across the piston to
  prevent pressurized fluid from leaking as the
  fluid is pushed because of pressure of the
  piston. Likewise, rod seals sustain pressure in
  the cylinder and prevent fluids from leaking out.
  In absence of rod seals, a leakage of fluid can
  affect equipment performance abundantly, and also
  leads to serious environmental issues. Together
  rod and piston seals add to the functionality of
  motors.
• Wipers, also known as scrapers, filter out
  undesired elements such as dirt, dust and
  moisture from entering the cylinder.
  Contamination, in any form, not only affects the
  performance of a machine but also causes
  significant damage to the rod, cylinder wall,
  seals, and other components. Contamination leads
  to premature seal and component failure in a
  fluid power system.

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Guide Ring

• Guide rings act as cushion or barrier, and they
  are used to prevent metallic contact between
  axial and rotational components. Guide rings are
  used to prevent damage from side loading because
  they prevent different component from coming in
  contact with one another. Other than this, guide
  rings also strain contaminants, like dirt and
  moisture, sub-surface to prevent them from
  reaching the most critical sealing elements.
  Common examples of guide rings are resin-bonded
  fabric, guide tape and engineered plastics. They
  are used to guide and protect the rod and piston
  seals in a hydraulic cylinder.

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Conclusion

• The right selection of seal does not only add to
  the functionality of motor but also protects it
  from damages. Piston and rod seals Austin assure
  the best performance for hydraulic cylinder
  applications.

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