#118 Hot caustics and chlorine need cage-controlling.  Problem: A major chemical producer employed an electrolytic process to separate a brine of hot caustics and chlorine. This erosive and corrosive mixture at elevated temperatures can dramatically shorten the service life of valves. Ball and gate valves had cavities where the flow media could accumulate and prevent proper shutoff. There was also a desire for a valve with better fugitive emissions control than was provided by standard gate and ball valves. Of course, as always, cost was a major consideration. The Tufline Sleeved Plug Valve seemed to be the logical choice. It has no cavities where media can accumulate and it offers a double seal to atmosphere at a standard valve price. However, there was concern about the erosive effects of the brine on the valve's PTFE sleeve.        Solution: The plant engineers installed Tufline Cage-Controlled Sleeved Plug Valves. The cage assembly provides soft seat protection in throttling applications and in service with high pressure drop through the valve. The cage is contained within the plug. It is fixed in place by pins that are welded in the bottom of the valve body. With a caged plug, there is metal-to-metal throttling and metal-to-soft seat shutoff. The cage protects the seat from erosion by shielding the soft seat from direct flow impingement at the valve ports.  Results: Plant personnel around the world breathe easier knowing that the Tufline Sleeved Plug Valve is handling the most difficult and hazardous fluids at their facility. Index of all performance report case histories.