Friday 20 March 2015

Pitot Tube



           In its simplest form the Pitot tube comprises a small tube inserted into a pipe with the head bent so that the mouth of the tube faces into the flow. As a result, a small sample of the flowing medium impinges on the open end of the tube and is brought to rest. Thus, the kinetic energy of the fluid is transformed into potential energy in the form of a head pressure (also called stagnation pressure).
           
            The simplest pitot tube consists of a tube with an impact opening of 3.125 mm to 6.35 mm diameter pointing towards the approaching fluid. This measures the stagnation pressure. An ordinary upstream tap can be used for measuring the line pressure.

            The velocity equation for the pitot tube is given by
            v = Cp 2gh
            Where: Cp is the pitot tube constant.

            Pitot tubes are generally used only in low-to-medium flow gas applications where high accuracy is not required.

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