With the parabolic nozzle, which has a throat diameter of 2 in, Reynolds Hmbers of up to 140,000 may be attained a further nozzle having a bore of 3 in is also supplied and is shown in Fig1A. This nozzle is designed in accordance with the recommendations of British Standard 1042 Part1: 1984 and is known as an
“ISA 1932 nozzle”. This nozzle imposes less restriction on the flow and henco permits Reynolds Numbers of
up to 200,000.