Ajutage refers to a tube fitted to the mouth of a vessel for the purpose of modifying the discharge of water. If cylindrical or conical, it considerably increases the efflux of water.
In the former case,when the length of the ajutage does not exceed four times its diameter, the increase is in the proportion of 1.33 to 1. With an ajutage composed of two conic frustrums on a horizontal axis, the bases opening respectively into the vessel and into the atmosphere , the length of the outer frustrum being three times that of the inner one, and the opening into the vessel being seven-eighths the size of the delivery-opening, the proportion of 3 to 2 has been obtained.
Ref: 86217/2006-09-13