Design World

  • Home
  • Technologies
    • 3D CAD
    • Electronics • electrical
    • Fastening & Joining
    • Factory automation
    • Linear Motion
    • Motion Control
    • Test & Measurement
    • Sensors
    • Fluid power
  • Learn
    • Ebooks / Tech Tips
    • Engineering Week
    • Future of Design Engineering
    • MC² Motion Control Classrooms
    • Podcasts
    • Videos
    • Webinars
  • LEAP AWARDS
  • Leadership
    • 2022 Voting
    • 2021 Winners
  • Design Guide Library
  • Resources
    • 3D Cad Models
      • PARTsolutions
      • TraceParts
    • Digital Issues
      • Design World
      • EE World
    • Women in Engineering
  • Supplier Listings

Advancements in Double-Acting Rotary Seals Prove More Effective

By Beth Figliulo, Fluid Power Segment Manager | November 14, 2018

Share

Leaking rotary seals can create a headache for anyone within the fluid power industry. There is a fine line between ensuring a rotary seal has enough lubrication to prolong a seal’s life and having too much to cause leakage. Without sufficient lubrication, the seal life is shortened due to excessive wear and heat. System costs also increase due to additional frictional torque.

To remedy potential issues with leakage, fluid power design engineers can take a few precautions, such as the use of redundant seals or a drain line.  In fact, manufacturers can lower hardware cost and increase functionality with new sealing innovations designed to decrease torque and increase seal life.

For instance, utilizing a seal with an integrated check valve function and high contact force on the seal edge helps to increase lubrication while decreasing leakage. In redundant sealing systems, the check valve function automatically releases inter-stage pressure build up when system pressure drops.

Achieving Optimal Sealing Efficiency

Seal designs with valve ports made from both sides of the O-Ring profile to the space in the center provide a lubricating groove.  Like other O-Ring activated slipper seals the initial squeeze of the O-Ring ensures enough contact pressure between seal and mating surface to provide sealing at low pressure. As the system pressure increases, the O-Ring and the seal body have direct contact force on the sealing surface to ensure sealing efficiency at all pressures. A double-acting four-lip seal installed in the lubricating groove prevents static leakage through the ports.  When this lip seal is pressurized from one side, it opens the port on the pressure side, equalizing the pressure beneath the elastomer ring.

Seal diameters can range from about 1 inch to 2 feet 2 inches (22mm to 660mm) and operating temperatures can be from -22 °F to +392 °F (-30 °C to +200 °C), making them well suited to fluid power applications.   

Less Compression and Better Lubrication

A solution such as this provides multiple seal points on the ring, requiring less compression to provide an effective seal.  By providing less force to seal, there is less friction and wear, reducing potential downtime. When pressurized, the elastomer ring opens the port on the pressure side and equalizes the pressure beneath the double-acting four-lip ring – pressure balancing the seal by more than half. Shifting pressurization through the ports renews the fluid in the space between the “legs,” improving lubrication under the seal.  This level of lubrication is optimal because the grooves on the inner and outer diameter of the ring maintain lubrication, lowering friction and extending the life of the seal.

The sealing industry has answered a need for rotary seals that run at higher speeds at higher pressure and extended seal life for more demanding applications where a high pressure to velocity value is required.  A double-acting rotary seal such as this delivers twice the pressure velocity and a fifty percent reduction in friction. In testing, wear of the seal and O-Ring was so low that its measurement was inconsequential.

Summary

Specialized rotary seals can be well suited to address high-speed, high-pressure applications that need continuous service at high and low pressure velocity (PV) values.   The seals give improved performance in oscillating conditions and applications involving frequent pressure and/or velocity changes.  In fact, these double-acting rotary seals tested with low frictional torque at all pressures from 0.5 MPa / 72.5 psi and above with low sensitivity to pressure increases from 0.5 to 20 MPa / 72.5 to 2900 psi.  They are ideal for equipment for which a long service life is required in demanding service conditions.  

Hydraulic swivels, lead-troughs, rotary connections with swivel movements, excavators, hydraulic rotators, robots, manipulators, indexing tables, pivoting motors, hydraulic motors, blow molding machines, top drives and core cutting equipment and other applications needing increased performance would really benefit from rotary seals that can run at higher speeds combined with higher pressures.  They not only achieve these requirements but generate lower heat, which reduces the wear on the seal.  For the equipment operator that means lower overall costs due to reduced maintenance requirements and energy consumption.


Filed Under: Product design

 

Related Articles Read More >

Read COMSOL News 2021
PCB mills
Basics of printed circuit board milling machines
scilab
The top ten free engineering math software packages
hardcore programming for mechanical engineers
Book Review: Hardcore Programming for Mechanical Engineers, By Angel Sola Orbaiceta

DESIGN GUIDE LIBRARY

“motion

Enews Sign Up

Motion Control Classroom

Design World Digital Edition

cover

Browse the most current issue of Design World and back issues in an easy to use high quality format. Clip, share and download with the leading design engineering magazine today.

EDABoard the Forum for Electronics

Top global problem solving EE forum covering Microcontrollers, DSP, Networking, Analog and Digital Design, RF, Power Electronics, PCB Routing and much more

EDABoard: Forum for electronics

Sponsored Content

  • Global supply needs drive increased manufacturing footprint development
  • How to Increase Rotational Capacity for a Retaining Ring
  • Cordis high resolution electronic proportional pressure controls
  • WAGO’s custom designed interface wiring system making industrial applications easier
  • 10 Reasons to Specify Valve Manifolds
  • Case study: How a 3D-printed tool saved thousands of hours and dollars

Design World Podcasts

May 17, 2022
Another view on additive and the aerospace industry
See More >
Engineering Exchange

The Engineering Exchange is a global educational networking community for engineers.

Connect, share, and learn today »

Design World
  • Advertising
  • About us
  • Contact
  • Manage your Design World Subscription
  • Subscribe
  • Design World Digital Network
  • Engineering White Papers
  • LEAP AWARDS

Copyright © 2022 WTWH Media LLC. All Rights Reserved. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media
Privacy Policy | Advertising | About Us

Search Design World

  • Home
  • Technologies
    • 3D CAD
    • Electronics • electrical
    • Fastening & Joining
    • Factory automation
    • Linear Motion
    • Motion Control
    • Test & Measurement
    • Sensors
    • Fluid power
  • Learn
    • Ebooks / Tech Tips
    • Engineering Week
    • Future of Design Engineering
    • MC² Motion Control Classrooms
    • Podcasts
    • Videos
    • Webinars
  • LEAP AWARDS
  • Leadership
    • 2022 Voting
    • 2021 Winners
  • Design Guide Library
  • Resources
    • 3D Cad Models
      • PARTsolutions
      • TraceParts
    • Digital Issues
      • Design World
      • EE World
    • Women in Engineering
  • Supplier Listings