Aviation Stack Exchange is a question and answer site for aircraft pilots, mechanics, and enthusiasts. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I've read phrases like "All gas turbine engines use pressurized seals for their shaft bearing compartments to keep [...]" but I do not understand what "seals" means. In spanish we haven't a word for it.

share|improve this question
I think this is better on-topic at ell.stackexchange.com – sanchises Mar 23 at 10:07
I'm voting to close this question as off-topic because it is a request for a dictionary definition which applies to almost any mechanical system so isn't really a question about aviation. – David Richerby Mar 23 at 15:54
Although it request dictionary definition, it can be answered in aviation sense given OP gave enough context. – vasin1987 Mar 23 at 16:27
Of course there is a spanish word for it: junta. Seventh definition: dle.rae.es/?id=Md1HbkD – mns Mar 23 at 18:29
@DavidRicherby But you only know it isn't related specifically to aviation if you know about aviation. It's entirely possible that aviation uses a different (or more likely, a specialized) definition of a seal that carries with it implicit knowledge of avionics. I'd be worried if the site was nothing but terminology questions, but I don't see anything wrong with the question itself. – corsiKa Mar 23 at 19:21
up vote 10 down vote accepted

Seal means sello mecánico.

Bearings are actually located in sumps (cárter). This picture is taken from this answer. You can see the two sumps:

enter image description here

Sumps are watertight and there are seals between the shaft and the sump, or between the shaft and the bearing to contain oil (lubricant) inside. This is a simple oil seal:

enter image description here

A more complex seal looks like this one:

enter image description here

Turbo engines oil seals are specially selected to bear the high rotation speed of the shafts (wear), and the high operating temperature of the engine core (adjustment and bending). Carbon seals are commonly used.

See on Youtube: Carbon Seals - Turbine Engines: A Closer Look.

share|improve this answer
I find searching for "juntas de estanqueidad" on google gives me gaskets, not seals. Is there some other translation? – Andy Mar 23 at 13:34
@Andy: Thanks for pointing out. I updated with sello mecánico (Google search). – mins Mar 23 at 13:44

"Seal" is used here to mean "closure". Specifically, a seal is a mechanism which prevents gases (or liquids) from crossing a barrier.

For instance, a rotating shaft must be connected to a fixed structure by means of a bearing (which allows it to rotate). If dirt or liquid were to enter the bearings, it would damage the mechanisms inside. Therefore, seals are used to keep dirt and liquids out of the bearings. Here is an example from general machinery: http://www.machinerylubrication.com/Read/838/protect-bearings

share|improve this answer

Seals are things like this:

Pressurised shaft seal

they prevent oils and other fluid from contaminating areas where they do not belong (and they prevent impurities from contaminating the oils).

You can see one of these used in this assembly diagram (the "oil seal") to protect the ball bearing assembly:

Shaft assembly diagram

(Image source)

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.