Screwed Valve End Connections

Screwed Valve End Connections. Male threads of various forms may be used for special purposes, but as a rule screwed end valves have female pipe threads, wither tapered for assembly to taper threaded pipe, or parallel for assembly to taper or parallel threaded pipe. In taper-to-taper and in taper-to-parallel connections, the pressure-tight joint is made on the threads. In parallel-to-parallel connections, the pressure tight joint is made by compressing a grummet or gasket against the end face of a valve. Screwed ends, usually confined to pipe sizes of 150mm and smaller, are widely used for bronze valves and to a lesser extent in iron and steel valves.