STF sleeved plug valve is classic designed on inner structure,sleeve are well fixed in the body and protected by 360. lip on the path, top seal including PTFE ring , diaphragm and metal ring ensure no leakage on plug stem, most PTFE sleeve are only used below 220C, but STF special plastic sleeve can work under 300C.
Body and plug’s material are available from WCB to high alloy steel such as hastelloy ,titanium and Zirconium.