O-ring sealing
Close
Login to Your Account
Results 1 to 17 of 17

Thread: O-ring sealing

  1. #1
    Join Date
    Feb 2020
    Country
    UNITED STATES
    State/Province
    Idaho
    Posts
    4
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Question O-ring sealing

    Hello. I need to make a gasproof sealing between two pieces of metal inside a tube. Like this:

    18170ed8-49ba-4ccc-a7d0-277cae0a14aa.jpg66f7e3f7-3de5-4355-b5ad-01b7634d0b33.jpg

    I made two examples in the pictures above, the difference is the edge inside of the tube. I will put a O-ring at the edge that will seal the ball when it’s pushed against it, but I don’t know if the edge should be angular or smooth/round for best sealment. What do you think?

  2. #2
    Join Date
    Jun 2015
    Country
    UNITED STATES
    State/Province
    Colorado
    Posts
    525
    Post Thanks / Like
    Likes (Given)
    1086
    Likes (Received)
    183

    Default

    Lots of variables that matter here including but not limited to: environment pressure, static or dynamic application (reciprocating or rotary), o-ring durometer, squish allowance, material finish and hardness, etc. Check out the various o-ring gland design guides by Parker or Apple Rubber to get a better idea of the variables you need to define. Lower pressures/static applications are more forgiving to design flaws.

    With just the info given I would go with the angled surface versus a sharp corner that could cut the o-ring. Again all depends on your application. Give us some more details and we can get you a better answer.

  3. #3
    Join Date
    Feb 2020
    Country
    UNITED STATES
    State/Province
    Idaho
    Posts
    4
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    It’s for a dynamic reciprocating application. The O-ring can easily be replaced by a new one, so squishing is allowed if it make it seal better. The important part is that every new O-ring will seal the first time pressure is applied.

    The tube is made out of steel.

    Would a copper O-ring behind a rubber O-ring make a good seal?

  4. #4
    Join Date
    Oct 2005
    Country
    UNITED STATES
    State/Province
    Pennsylvania
    Posts
    16,499
    Post Thanks / Like

    Default

    Quote Originally Posted by BugRobotics View Post
    Lots of variables that matter here including but not limited to: environment pressure, static or dynamic application (reciprocating or rotary), o-ring durometer, squish allowance, material finish and hardness, etc. Check out the various o-ring gland design guides by Parker or Apple Rubber to get a better idea of the variables you need to define. Lower pressures/static applications are more forgiving to design flaws.

    With just the info given I would go with the angled surface versus a sharp corner that could cut the o-ring. Again all depends on your application. Give us some more details and we can get you a better answer.
    Quote Originally Posted by Develop View Post
    It’s for a dynamic reciprocating application. The O-ring can easily be replaced by a new one, so squishing is allowed if it make it seal better. The important part is that every new O-ring will seal the first time pressure is applied.

    The tube is made out of steel.

    Would a copper O-ring behind a rubber O-ring make a good seal?
    Important part hi-lighted....

  5. #5
    Join Date
    Sep 2011
    Location
    Langley, B.C.
    Posts
    1,738
    Post Thanks / Like
    Likes (Given)
    368
    Likes (Received)
    1015

    Default

    If I understand this right the green circle is a "ball" that slides inside the tube (shown in gray). The O-ring
    fits between the ball and the shoulder on the inside of the tube. If you use a tapered shoulder and there is
    going to be much pressure on the ball I think you're going to have problems with the O-ring being pushed
    deeper into the tube and breaking the seal. I would stick with a square shoulder and even consider making
    it wider so there is a solid edge for the O-ring to push against--much less chance of it moving. As long as you
    design the fit so the ball can't touch the shoulder of the tube I see no advantage whatsoever in using a
    tapered shoulder...

  6. Likes awander, Scottl liked this post
  7. #6
    Join Date
    Dec 2015
    Country
    UNITED STATES
    State/Province
    Illinois
    Posts
    458
    Post Thanks / Like
    Likes (Given)
    165
    Likes (Received)
    259

    Default

    https://www.parker.com/Literature/O-...ORD%205700.pdf

    This is the one of the resources suggested. Perhaps look at page 4-21.

    When you say this is a dynamic reciprocating seal are you saying that the green ball will be bouncing up in down against this seal? If that is the application I think you may want to redesign your seal. If your pressure is too high then I think the O-ring will permanently deform and fall out or at least loose it's ability to seal without some type of gland supporting/protecting it.
    Last edited by kenton; 02-11-2020 at 03:06 PM. Reason: word order

  8. Likes n2zon liked this post
  9. #7
    Join Date
    Jan 2007
    Location
    Norfolk, UK
    Posts
    19,242
    Post Thanks / Like
    Likes (Given)
    14707
    Likes (Received)
    14844

    Default

    Ditto what he said

    Here ya go all 292 pages of O ring lore https://www.parker.com/Literature/O-...ORD%205700.pdf

    Hint - don't try and reinvent the wheel / come up with your own solution, AFAIK if it can be done with O rings it's in there.

  10. Likes AARONT, BugRobotics, digger doug, n2zon liked this post
  11. #8
    Join Date
    Feb 2020
    Country
    UNITED STATES
    State/Province
    Idaho
    Posts
    4
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    Just a curious question, I’ve seen O-rings made of rubber and copper, but is there any other materials they are made of? For example, isn’t lead softer than copper?

  12. #9
    Join Date
    Nov 2018
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    357
    Post Thanks / Like
    Likes (Given)
    170
    Likes (Received)
    197

    Default

    Some good information so far in here, and to point you in the right direction, what you want to do is covered on page 125 of the full manual linked by Limy Sami. A configuration like that (tapered or straight) will work as long as the ball seats against the shoulder, the o-ring is squeezed, and the volume available to the o-ring is somewhat greater than the gap between the ball and the wall.

    The issue you can see right away based on Parker manual, page 125 is that in either direction, once the ball moves away from the seated position but the seal hasn't been broken, the o-ring will get blown out of position. To retain it, some care will need to be taken in groove design. This is based on (differential) pressure, pressure direction, o-ring durometer, and fluid to be sealed, none of which you have shared here. "Gasproof" as ambiguous since it could refer to liquid fuels or any variety of gasses.

    More general information:

    - Sharp corners are generally no-nos. They tend to cut o-rings even if you don't expect it to. They move around under pressure more than you might think.

    - Permanent deformation happens in all situations and all designs. The degree of such is based on the rubber compound, the temperature, time, and deformation. Effective designs are those that can tolerate some amount of permanent deformation. 25% of the applied squeeze becoming permanent is typical.

    Edit to add re: copper seals, typically copper will be used in specialty applications like pulling hard vacuum where it is unacceptable to have even the small amount of seepage rubber will allow through the material. It requires special groove and flange design and typically needs loads and loads of loading, like bolts every inch or two. Not something you're likely to make effective by tossing a ball towards it under pressure and hoping for the best.

  13. #10
    Join Date
    Sep 2010
    Location
    Oklahoma City, OK
    Posts
    4,681
    Post Thanks / Like
    Likes (Given)
    804
    Likes (Received)
    1923

    Default

    I think you should find a copy of the Parker O-ring handbook. It describes all of that stuff in great detail.

    They'll even mail you a print copy upon request.

    Damn- late to this party. I do however suggest that anyone needing this info on a reg basis request their catalog.

  14. #11
    Join Date
    Jun 2013
    Location
    Northern Il
    Posts
    1,364
    Post Thanks / Like
    Likes (Given)
    711
    Likes (Received)
    1257

    Default

    Quote Originally Posted by Develop View Post
    Just a curious question, I’ve seen O-rings made of rubber and copper, but is there any other materials they are made of? For example, isn’t lead softer than copper?
    Those are not actually O-rings. Those are seal rings for banjo fittings. Used for high pressure applications such as fuel injection lines and brake hose connections.

  15. #12
    Join Date
    Dec 2010
    Location
    Uruguay
    Posts
    83
    Post Thanks / Like
    Likes (Given)
    3
    Likes (Received)
    23

    Default

    Could we have dimensions? Inner ODs of the tube, weight of the ball.

  16. #13
    Join Date
    Oct 2005
    Country
    UNITED STATES
    State/Province
    Pennsylvania
    Posts
    16,499
    Post Thanks / Like

    Default

    Quote Originally Posted by RODELU View Post
    Could we have dimensions? Inner ODs of the tube, weight of the ball.
    Why ?
    To doo the OP's homework ?

    Several people have provide good links for the OP to READ & LEARN.

  17. #14
    Join Date
    Jan 2005
    Location
    Victoria, Texas, USA
    Posts
    4,114
    Post Thanks / Like
    Likes (Given)
    2333
    Likes (Received)
    1046

    Default

    Quote Originally Posted by Develop View Post
    Just a curious question, I’ve seen O-rings made of rubber and copper, but is there any other materials they are made of? For example, isn’t lead softer than copper?
    I have used Teflon O-rings before in certain applications. There are a pain in the arus to install in a OD groove! Almost as bad when used in internal groove, too!

  18. #15
    Join Date
    Dec 2010
    Location
    Uruguay
    Posts
    83
    Post Thanks / Like
    Likes (Given)
    3
    Likes (Received)
    23

    Default

    Quote Originally Posted by digger doug View Post
    Why ?
    To doo the OP's homework ?

    Several people have provide good links for the OP to READ & LEARN.
    Doing somebody else´s homework is wrong but learning is never wrong, and one thing I like about this forum is knowledgeable people being extremely generous with their knowledge.

  19. #16
    Join Date
    May 2011
    Location
    southern in.
    Posts
    1,480
    Post Thanks / Like
    Likes (Given)
    1968
    Likes (Received)
    400

    Default

    Develope: I suspect you don't really understand how o-rings work. Take the info that BugRobotics and Digger gave you and study it well. Don't confuse them with gaskets or piston rings.

    JH

  20. #17
    Join Date
    Apr 2014
    Location
    Dutchess County NY
    Posts
    377
    Post Thanks / Like
    Likes (Given)
    96
    Likes (Received)
    91

    Default

    Quote Originally Posted by Limy Sami View Post
    Ditto what he said

    Here ya go all 292 pages of O ring lore https://www.parker.com/Literature/O-...ORD%205700.pdf

    Hint - don't try and reinvent the wheel / come up with your own solution, AFAIK if it can be done with O rings it's in there.
    This ^^^, The Parker O-Ring Handbook is one of my bibles.


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •