Sealing problem @ 60 bar

[RayJ2]

Hi all,

I have a seal design question.
I am designing a measuring device. This device will be used to test a series of products.
The products are closed metal tubes with a flange. (see links for screenshots)

http://tinyurl.com/3a5xgvt

http://tinyurl.com/32ytyus

http://tinyurl.com/3a2fkmm

These tubes must be put under waterpressure of 60 bar (870 psi / 6 MPa).

To do that, the tube is placed in a container, filled with water. A cover is placed and fixed, that pushes the tube with the flange onto a seal.
Pressure is applied and the test takes about 2 minutes to complete. So every 2 minutes, the cover is released and the tube is removed.
A new tube is inserted and the cover is placed again to hold the tube in place and to compress the seal.

Now which seal should I use for this?
My first idea was an o-ring (as shown on the drawings), but that will suffer from the continuous squeezing and unsqueezing.
Also, when the tube is pulled out of the container, I want the o-ring to remain in place. That's why I have the o-ring chamber tapered. But I don't know if that will be sufficient to keep the o-ring in place.

Does anyone have a better idea for sealing the metal tube against water? Taking into account the continuous opening and closing of the seal.

I was considering using a PTFE (teflon) seal. This, I can design according to my needs (to keep the seal in place).
But maybe teflon is too hard and will not seal properly...

Any ideas or suggestions?

Kind regards
Eddy

 

[flexibox]

Eddy,
Best to have an Oring groove in the housing per attached sketch. This should be OK to use continuously. Nitrile Orings are relatively cheap too if you damage during installation so make sure that you include chamfers and good surface finishes

 

[RayJ2]

Flexibox,
That could be an option.
But what I did not mention in my first post (to not unnecessary complicate my explanation) is that there are actually two different types of products (metal tubes).
One with a wide flange and one with a narrow flange. As shown here:

http://tinyurl.com/33oxucm

The one with the narrow flange will complicate sealing on the outside as in your sketch (although not impossible).
Also, I can not change the product design. The flange edge does not have a chamber (to easily insert the tube in the o-ring) and I can not add one.

But I will keep your suggestion as an option though.
Thanks!

 

[RayJ2]

That should be: "The flange edge does not have a chamfer"

 

[flexibox]

Based on the latest information please refer to the attached sketch which I believe will solve your issue.

 

[RayJ2]

Flexibox,
I agree. I have come to the conclusion that o-rings might not be the best solution for this problem.
I am now looking at:
- Kantseals (from Trelleborg): square cross section rings, as in your sketch
- Quad rings (aka X-rings)
- Fluid connector seals, DIN 3869
- Bonded seals (aka USIT rings, multiseals)

One of these should do the trick.

An advantage that all of these seals have in common is that it is much easier, than o-rings, to keep them in place when the metal tube is pulled out of the container.

Thanks a lot for your input!

Kind regards
Eddy