Double sealed Gate valves

[Danlap]

Dear valve experts,

Looking forward for some insights Re: double expanding Gate valve.
Long story short, I have a nasty product (catalyst + other products) operates at 400 degree Celcius and 70 barg. There are 2 Gate valves (8"-600#) operated only during start up and shut down (MOV in the upstream side and Hand Operated on the downstream side). And installed horizontal
Since this product can be hardened, and potentially stay (as solid material) in Gate valve pocket (top and bottom cavity), our IPF and SIL study recommend 4 sealed side (1 valve provide double sealing surface). In order to protect the cavity from pocketing while it is in fully Open and Fully close.

Have try double expanding gate with Cam connection (between the two wedges) and also spring connection for the last several years. However stuck Open or close somehow often occurs. And occasionally the pocketing still persist.
Shall continue with double expanding Gate design? which one is better (Cam or Springs)?
Any ideas of other type for (Gate) Valve?

PS:
Gate and seat is full stellited, Springs are Inconel, Motor is fully weight (counter) supported
Valves are Normally Close
Valve To be closed (Plant start up) after reaching 400 degree Celcius. And open (Plant about to be shut down) at 400 degree Celcius (70 barg)
After the hand operated valve is stack to atmosphere
Revision of Operating protocol is not desired


Thank you,
Regards,
MR

Greenfield and Brownfield have one thing in common; Valve(s) is deemed to "run to fail" earlier shall compared to other equipments

 

[gerhardl]

Hello Muktiadi!

Perhaps this type of valve could be interesting.

http://www.stainlessvalveco.com/

 

[Danlap]

Hello Gerhardl,

Thank you for the information. Yes, it is interesting indeed and look promising.
A bit un-orthodox design for severe service application. Understanding that most people will perceive that as a combination of Knife and Slab Gate valve.
For sure will give it a try.

Kind regards,
MR

Greenfield and Brownfield have one thing in common; Valve(s) is deemed to "run to fail" earlier shall compared to other equipments

 

[donf]

Muktiadi,

I second Gerhardl's recommendation. Stainless Valve is certainly worth contacting.

Regards,

Don