Smi/swastik plug valves are used for gas pipelines under comparatively higher pressure conditions. Grease, when pressed into the valves, lifts the plug, lubricating seat surfaces and easing operation. The inserted grease causes a thin oil film on the plug surface, assuring tight closure when the valve is shut. The body is made of gray cast iron with ample wall thickness, and is generally designed in flanged ends. The plug is made of same quality cast iron as of body, designed in conical shape to secure wedge effect, keeping a perfectly tight closure. Sealing grooves are provided on the plug surface, for lubricating seat faces. In smaller sizes the valves are operated by lever directly connected to the plug, and gearing or other method are used for larger sizes.
