beaing isolator in pressure vessel

[akshayjain1010]

hello everyone,
i am planning to use a bearing isolator in a pressure vessel having a high pressure steam of 50 bar,in that there will be a shaft rotating in the vessel.
can anybody please tell me that whether a bearing isolator can prevent the leakege of steam from that??


-akshayjain1010

 

[clay87]

Typically they are not designed for differential pressure of more than a few inches water. They are normally held in place with o ring and very light press fit. Me thinks you may need a mechanical seal.

Or maybe a low pressure chamber with a throttle bushing to break down the pressure before installing a bearing isolator (requires bleeding off some steam).

 

[LittleInch]

Also look at magnetic couplings as these have no hole in which you need to seal anything. You need something proper to do this, not a loose fit flimsy affair.

To be honest, getting it wrong with 50 bar steam doesn't bear thinking about so I hope someone else is approving your design.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[akshayjain1010]

thanks for replying...but if we consider the mag-drive, then, keeping in mind the high temperature inside the vessel, will the magnetic drive be equally efficient and i am also thinking whether its life would be affected due to prolonged exposure to the high temp...

 

[LittleInch]

I really don't knnow - YOu need to contact a few vendors, but 50 bar isn't so high and steam not too bad if it leaks a very small amount so I think some good mechanical seals should do the trick. Again, you need to talk to vendors - try Crane seals first - then decide if you want xero leakage guarenteed ( in which case go for a mag drive) or whether you can withstand the odd drip or occasiaonal failure which then needs the seals to be replaced.

Most seals work best when the shaft is constantly moving, so it will depend on your application - only you know what it is. ?if there ar elong period of no movement or slow rottion, seals tend not to like it so much - most are designed for pumps and compresosrs where the shaft rotates at a fairly constant speed.

What are you doing in this vessel for interest sake?

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[akshayjain1010]

Also I have seen some uses of mag drive,in all such applications there is a coupling(mag) between the shafts but in our case,one of the shafts is inside the vessel and if we try to connect these two then apart from the air gap there will also be a metal sheet in between ,will it work in this case as well?

 

[LittleInch]

Yes, Talk to the vendors, look it up on the web. They make these for chemical pumps with very dangerous chemicals which can't leak so the vessel is metal, but has no shaft coming out of it.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[akshayjain1010]

thanks a lot!!!

 

[akshayjain1010]

here i've attached an image of my design in which i am most concerned about the steam leakage from the encircled region...although now i am thinking on some other sealing and mag drive as well but thought that this image might help in better understanding of the problem...through this vessel i am planning to treat waste material.

 

[clay87]

You thought about a vertical installation? Not sure what's going on in there or how fast it is turning but I imagine you will need some radial bearings and a thrust bearing. maybe easier to suspend the rotor and have some low-load guide bearings.