ABSTRACT
The venturi tube as designed by Clemens Herschel in 1887, and described in the ASME handbook. The classic venturi is always manufactured with a cast iron body and a bronze or stainless steel throat section. In the 1950s, in an effort to reduce costs and laying length, manufacturers developed a second generation, or short-form. The pressure taps are located one-quarter to one-half pipe diameter upstream of the inlet cone and at the middle of the throat section. A venturi tube may be installed in any position to suit the requirements of the application and piping. There is no limitation on piping configuration downstream of the venturi except that a valve should be no closer than 2 diameters. There are several proprietary primary-head-type devices which have a higher ratio of pressure-developed-to-pressure-lost than a venturi tube. The differences between the two nozzles are basically a flattening of the ellipse in the high beta ratio version.
