The Hollow jets (HJ) – original operational gate for lower discharges of dam reservoirs is at present the most reliable control gate with very good control properties, high flow coefficient and very good tightness, which provides for effective aeration of the outflow jet and absorption of its kinetic energy – creation of the “hydraulic jump” – in case of correct design of the discharge chamber of square section (chamber of shape XIII), or a cylindrical chamber with conical insert. Other of its advantages to other types of control gates include its simple design with minimum operation and maintenance requirements.

Use:

medium: river water