CS Valve in DSS Pipe

[nickypaliwal]

Our client has a 24 inch Carbon Steel Line with a valve of line size. This line comes from a 32 inch header line of Carbon Steel.

Due to flow rate, 24 inch line is experiencing erosion problem. Also the downstream line is DSS so we plan to replace the 24 inch CS line with DSS.

Can we still use 24 inch CS valve in new 24inch line with DSS. Valve doesn't show any problem ?

 

[metengr]

Is the carbon steel valve butt welded or bolted with a flange to the DSS pipe system?

 

[nickypaliwal]

We have planed to bolt it using insulation gasket. Is that acceptable ?

 

[metengr]

Yes. I would also use coated bolts/nuts or plastic sleeves over the bolts to ensure the bolt is fully insulated from the flange.

 

[EdStainless]

And just to make sure, the valve isn't coated, right?
Isolating it is the right way to go.

My hunch is that the valve metallurgy is different from the piping.
Even though both at CS, the valve may have enough alloying to help minimize erosion damage.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[nickypaliwal]

Yes, the valve is not coated. Valve does not show any sign of erosion damage.

I believe you both support our plan with only thing is to avoid any direct contact of CS and DSS.

 

[KMur]

What about valve trim material? Trim material should be DSS and Hard facing also applicable. Am I correct??

Thanks

 

[EdStainless]

No, for galvanic reasons it would be best if all trim was steel.
Maybe a bit higher alloy than the body, but it should be galvanicly similar.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube