Published on December 20, 2016
1. TRANSDUCERS & ITS INDUSTRIAL APPLICATIONS PRESENTED BY AJAY KUMAR ROLL NO. 1305232005 E.I ,III YEAR
2. TYPES OF TRANSDUCERS PRESSURE MEASUREMENT TEMPERATURE MEASUREMENT FLOW MEASUREMENT
3. FlOW MEASUREMENT • ORIFICE PLATE • VENTURI TUBE • ROTAMETER
4. Differential Pressure Flowmeters The Orifice Plate • The orifice plate is the simplest and cheapest. It is simply a plate with a hole of specified size and position cut in it, which can then clamped between flanges in a pipeline • The increase that occurs in the velocity of a fluid as it passes through the hole in the plate results in a pressure drop being developed across the plate. • After passing through this restriction, the fluid flow jet continues to contract until a minimum diameter known as the vena contracta is reached.
5. The Venturi Tube • The classical or Herschel Venturi tube is the oldest type of differential pressure flowmeter (1887). • The restriction is introduced into the flow in a more gradual way • The resulting flow through a Venturi tube is closer to that predicted in theory so the discharge coefficient C is much nearer unity (0.95). • The pressure loss caused by the Venturi tube is lower, but the differential pressure is also lower than for an orifice plate of the same diameter ratio.
6. • The smooth design of the Venturi tube means that it is less sensitive to erosion than the orifice plate, and thus more suitable for use with dirty gases or liquids. • The Venturi tube is also less sensitive to upstream disturbances, and therefore needs shorter lengths of straight pipework upstream of the meter than the equivalent orifice plate or nozzle. • Like the orifice plate and nozzle, the design, installation, and use of the Venturi tube is covered by a number of international standards. • The disadvantages of the Venturi tube flowmeter are its size and cost. The Venturi Tube