Regarding Isolation and switch valves: ball valves vs “plug” style. I work for Armour Valve in Alberta, Canada we are the representative for SchuF Coker Valves (Germany) both Switch and Isolation. Our valves differ from others based on ease of maintenance, the top and bottom of the valve can be removed to decoke should you lose steam at the purges. Yes they can be automated and interlocked. I would love to further talk with you or anyone else interested. Send me an e-mail at email@example.com when you get a chance.