INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

submarine seals

submarine seals

(OP)
I`d be really interested in an explanation of how submarine prop-shafts turn whilst maintaining a water tight seal.
Andy

RE: submarine seals

As these are relatively large diameter seals they are normally split seals. Being split they generally have high leakage rates compared to non split faces. The leakage is collected and pumped away.

That my understanding, I don't know how they deal with a failure but if you really want to know I can find out for you as I do have a contact in the industry.

RE: submarine seals

(OP)
Thanks,
I suppose in terms of pressures its not a huge level compared to some seals...
Maybe its the weak spot in a submarine though...
Andy

RE: submarine seals

Hi!

On seals used for this application it exist a deformation of the seal, into the housing, to do the job to avoid the ingress of water into the system. By the way, all these elements are ready to withstand friction. Nevertheless, friction, in this case, will not be very important since:
- Rotation on a shaft propeller is low
- Seal is continuously cooled by water

Once installed, as you say, you have got a contact-pressure against the shaft. This one, due the material properties and friction of the seal, gives to the final system (engine or whatever rotates the shaft) a minimal torque that can represent about a 5% loss of power (value to be calculated on each case). So shaft continues rotating without any trouble

To do this job you've got several kind of seals, including mechanical seals.

Most popular ones are packings and PTFE or plastic bushes, but, depending on criteria, you can go further. As you go down (and pressure increases) you need a seal more capable to withstand such pressure. In this case you have got special rotary seals (some are split to be easier the installation) to do the job

Even I have seen a propeller using just an O-Ring as the unique seal.

We have made applications on submarine equipments for critical environments, and having, inside, analytical instruments. In these cases, you can apply up to spring energized seals due that these are, mostly, made in PTFE, so power-loss (due low friction) decreases dramatically compared to a split seal.

On almost every case, most important point is to keep centered the shaft due that pressure is not such important as it should be a right guiding of the shaft.

http://www.hidromar.es

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close