The Dall Tube was actually developed by Horace E. Dall, who was an ABB (Kent) hydraulics engineer. Being essentially an adaptation of the Venturi Tube, it has a unique flow path design which, compared with the Venturi, gives a much shorter overall length (1.75D instead of 5D), and an elevated differential pressure (for the same flowrate and throat ratio) but has a much lower irrecoverable pressure loss. It is suitable for clean liquids, gases and steam.
There are two variants, based on differing manufacturing methods :
- DTF Fabricated Dall Tube with low pressure loss
- DTI Insert version with shorter length and lower weight, but with higher pressure loss
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