Autobiography of a Corporate Slave

The size of pipes, fittings, flanges and valves are given in two Units NPS = Nominal Pipe Size (Inches) DN = Diameter Nominal (Metric) Following is the comparison : Diameter Nominal DN (mm) Nominal Pipe Size NPS (inches) 6 1/8 8 1/4 10 3/8 15 1/2 20 3/4 25 1 32 1 1/4 40 1 1/2 50 2 65 2 1/2 80 3 100 4 150 6 200 8 250 10 300 12 350 14 400 16 450 18 500 20 550 22 600 24 650 26 700 28 750 30 800 32 900 36 1000 40 1050 42 1100 44 1200 48 1300 52 1400 56 1500 60 1600 64 1700 68 1800 ...

A  valve  is a device that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. They perform any of the following functions.   Starting and stopping or isolating fluid flow. In an open valve, fluid flows in a direction from higher pressure to lower pressure.  Controlling or varying (throttling) the amount of fluid flow by change of direction or restriction.  Checking the flow or controlling the direction of fluid flow and preventing backflow. Regulating downstream system or process pressure. Relieving component or piping system of a certain pressure. The word is derived from the Latin valva, the moving part of a door, in turn from volvere, to turn, roll. Valves may be operated manually, either by a handle, lever, pedal or wheel. Valves may also be automatic, driven by changes in pressure,...