Lubricated plug valve vs. ball valve for natural gas service natural gas service?Bellows Seal Valves

Lubricated plug valves are inherently firesafe.
They are also quite inexpensive. After all it's a simple shape to cast and not really a lot of machining.

Check ValvesAs for lubrication, there's the weak point.Widely misunderstood that the stuff pumped in is "sealant".Its job is to seal and to lubricate and to hydraulically lift the plug out of contact with the body.The sealant should be selected for compatibility with the process material so that it neither is soluble in it nor contaminating or reactivePlug Valves .Companies such as Nordstrom have approximately one bazillion different sealant formulations.The down side of that is that you might not get the right formulation, so the maintenance guys will either skip maintaining the valve or pump it full of the wrong goo.Some valves have a sealant injector built in the top of the plug shaft.Just give THAT a crank, THEN start horsing on the lever.Safety Valves

With recommended maintenance, maybe they would have a proper place in the world, but field maintenance on small valves is spotty to non-existent.

If you ignore a ball valve for a decade it will still most likely operate and there is a reasonable chance that it will hold pressure.Not so with a plug valve.Safety Relief Valves

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