Gate Valves in HF Acid Service

[Krausen]

Curious forum's opinions or experiences on this...I work at a refinery with an HF Alky unit. We've had many HF acid leaks in past with valve bolted bonnets, particularly with small bore gate valves. I would like to change to welded bonnet (threaded & seal-welded) style small bore gate valves going forward when we replace them. If I have issues with availability, I would like to request any new bolted bonnet gate valves to have a Kammpro style (Monel core) bonnet gasket, instead of spiral-wound or RTJ type. Talking with one major valve mfg (Velan), they claim they do not offer any of their small bore bolted bonnet gate valves with Kammpro gaskets. They can only offer with spiral-wound to their company standard. Velan does offer welded bonnet small bore gate valves, but it appears their lead times on these are very long.

 

[acdxxx177]

I don't know the size of your gate valves, but for smaller ones, using a Kammpro gasket (with a Monel core) might not be suitable for the seal between the bonnet and the body of very small valves. However, using a welded bonnet design can significantly improve the sealing performance in high-pressure and corrosive environments, which can help reduce leak risks.

[weld gate valve]​

If you're looking to further enhance the sealing performance, a bellows-sealed gate valve could be a good option. This design uses an elastic metal bellows to create a seal between the stem and the bonnet, maintaining excellent sealing even under extreme conditions and requiring almost no maintenance.

[Bellows-sealed gate valve]​

It's worth mentioning that our company also manufactures high-performance gate valves with welded bonnets, specifically designed for conditions like the ones you described. You can check out our website for more information. If you're interested in learning more about our products or discussing specific solutions, feel free to reach out to us.
view Wedge Gate Valve
view Guide to Analyzing External Leakage in Valves