Stationary bellows for Type C seal 1

[maintennance]

For seal type C and arrangement 3CW-FF, the bellows are made stationary and for this the drawings submitted is enclosed herewith. Is this arrangement is acceptable as the shaft sleeve have the pumping ring and the rotating seal faces are mounted . Thanks to clarify.

 

[flexibox]

This is the only way you can mount this arrangement. To answer your question yes it is acceptable having the pumping ring as a one piece sleeve. I would be more concerned with commissioning. Ensure that the seal is pressurized and vented correctly. Check that the seal In and Out connections allow venting in the seal chamber and also vent the cooling loop.

Looks good.

 

[maintennance]

Thank you very much flexibox. The seal flush plan is 02,53B, As you could see from the drawing attached , there is a vent provision in the stuffing box. Other than this what else the vents you were mentioning. Thanks to clarify.
Also for the 53B bladder material (Nitrile Buna N) we were suggesting to use Therminol 66. Whether this material is suitable for this barrier fluid?

 

[flexibox]

You need to vent the cooling loop high point. Therminol 66 is a heat transfer oil I have only sealed it with single seals and used Graphoil pkgs for the mechanical seal. I think Nitrile may be a problem for you but you need to double check this with the supplier. You may need to change the barrier fluid. It is a suitable barrier fluid but may not be compatible with the bladder material.

 

[gyaneshwarp]

The arrangement is OK.

But I doubt the circulation of the barrier fluid. How far it will be effective?

The circulation path is quite long.

 

[JJPellin]

This arrangement looks fine to me. We have similar seals running with good results. The axial flow pumping ring should be more effective than a typical radial pumping ring.

Johnny Pellin

 

[flexibox]

I tend to agree with you Johnny and value your opinions in this forum

 

[longeron]

One advantage of this arangment is that with the bellows facing inwards the seal faces are within the barrier fluid flow allowing more heat transfer to the fluid. Rotating the bellows forces the seal faces towards each end of the glands and out of the flow. In my experience this allows the heat generated at the faces to "cook" the stagnant barrier fluid around the faces causing varnish to build up on the hardware near the faces and possibly on the faces themselves.

The problem with systems such as these is that there is so much metal in the seal chamber. So little room for the barrier fluid. But that is another discussion regarding seal chambers and pump design.