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General:
Furnish and install as shown on the drawings a fl ow element
of the Hershel/Classical design differential pressure type as
manufactured by Preso.Confi guration:The Venturi inlet section shall be cylindrical with a pressure sensing tap and of the same diameter as the incoming pipe section and followed by a precise convergent section causing a uniform change in fl uid velocity. The cylindrical throat section with a pressure sensing tap, straight section and the exit cone shall have a precise angle in order to prevent permanent pressure loss that will not exceed 12% of the generated differential pressure. The beta ratio shall be determined by the manufacturer according to recognized standards and formulas. The discharge coeffi cient (Cd)
shall be linear and stable in the operating fl ow range, have a value above 0.985, and shall be achieved by adhering to the ASME standards.