Flanged joints flange faces

Flange face sheet gaskets at pipe joints. 

The PTFE and FEP pipes can be assembled without gaskets, the lining, which is swaged over the flange face, has sufficient resilience in itself. The non-gasketed joint is quicker and easier to assemble and more likely to achieve a leak-proof joint. 

The gasket consists of a lens shaped ring of heat treated low alloy steel or some other metal. The ring should be softer than the flange face. Flardness of the conventional lens ring varies with the metal required for the service condition. This joint is ideal for pipe and tube applications. It can be used for small connections and can be used for pressure vessel closures but is better suited for piping applications. 

Strainers of this type are normally designed with standard flange faces so that they can be fitted at a suitable flange joint in the pipeline. When removed they can be replaced by a spacer washer. These filters may take the form of a flat disc or a conical basket - some types of strainer basket are shown in Figure 3.1. Flat disc strainers are normally perforated plates, while basket strainers may be of perforated plate or supported wire mesh. Basket strainers can have a higher dirt capacity. 

Valve bodies are also standardized to mate with common piping connections flanged, butt-weld end, socket-weld end, and screwed end. Dimensional information for some of these joints and class pressure-temperature ratings are included in Sec. 10, Process Plant Piping. Control valves have their own standardized face-to-face dimensions that are governed by ISA Standards S75.03, 04, 12, 14, 15, 16, 20, and 22. Butterfly valves are also governed by API 609 and Manufacturers Standardization Society (MSS) SP-67 and 68. 

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