fluid seal using multiple grooves... what is it called? 2

[USAeng]

trying to remember the name of the fluid seal that has multiple grooves... you put the grooves say on the outside of a tube and that tube slips inside another tube... then the fluid starts flowing and I guess it makes eddys in the grooves that essentially stop the fluid from leaking between the tubes... I guess thats how it works... but cant remember the name... also I am wondering if there is any source to aid in design in such parts?

thanks

 

[TGS4]

The term that you are looking for is "labyrinth seal".

 

[DLite30]

you mean a labyrinth seal?

 

[USAeng]

thanks a lot- that is it

 

[Tmoose]

For constant direction of rotation some low pressure applications cut a spiral thread to create there is some pumping action. One groove would look like many.

 

[tbuelna]

USAeng,

Just a minor technical point, but most labyrinth seals don't actually "stop" leakage, they just tend to minimize leakage. Labyrinth seals commonly rely on a pressure differential across the seal to discourage the fluid from migrating past the labyrinth gaps. This normally works OK until the device is shut down. At that point, the liquid (or gas) that is being sealed will weep past the labyrinth seal.

Regards,
Terry

 

[kingnero]

as tbuelna said.

I've seen this used many tims on the spindle of horizontal milling machines (so a vertical setup of the seal).

It works very good when rotating, but when standing still (and even with the pressure diff.) it leaks. Minimal, but enough to make a mess. Every monday morning you can start by cleaning up the machine.

I wouldn't know how to design one, they're "off the shelf" products as far as I know.

 

[Tmoose]

Introducing air purge part way thru the labyrinth can be 100% in machine tools, and others.

 

[tbuelna]

Here's a COTS version of a labyrinth shaft seal:

http://www.inpro-seal.com/en-US/product/permanent-bearing-protection/

 

[Tmoose]

Looks like USAeng got his/her/their answer and has moved on.

links, one from 2003

http://www.eng-tips.com/viewthread.cfm?qid=146919&page=15

http://www.eng-tips.com/viewthread.cfm?qid=80034