The answer is that they each have advantages and disadvantages. Which system is better - a power jet or a suction nozzle? A vacuum is created which sucks up water and gravel but the material is pushed through the hose instead of being sucked through the hose, as in the case of the power jet. Hoses and other dredge accessories are not included.Ī suction nozzle works in a similar fashion to a power jet except instead of being attached directly to the header box the nozzle is attached at the far end of the material hose. #kesn2 outlet size: 2.0' inlet size: 1.25' Prices start at $135 for a 1.5' Suction Nozzle. Choose from 9 nozzle sizes in the drop down menu. Ideal for shallow water dredging - these Keene dredge suction nozzles are precision manufactured from thin walled plated steel tubing with machined orifices to create maximum suction pressure. A crab gets sucked through a slot not more than 1/8' wide.Keene Dredge Suction Nozzles Product Description:

There is a great video called crab vs pipe that shows what forces can be generated when an ambient air pressure pipe is cut at deep ocean depths. If the pipe nozzle blocked, the air could fill the pipe and the suction could lift about 500 pounds. That means an 8' pipe could lift an object weighing close to 250 pounds. If enough air is put into the pipe to fill it half full of air, the buoyancy of the water/air mix will give about 5psi suction at the nozzle. Water pressure at that depth is about 10psi. The pressure outside of the pipe at the nozzle is the maximum driving force available to move solids up the pipe, and that force gets very big very fast. The way it works is that when you submerge a pipe and then inject air bubbles, the bubbles rise and pull the water with them. When you use air, the buoyancy of the air provides a significantly greater driving force. If using water as the pressure driver, the actual lifting force is a fraction of the driving pressure. On the dredge pump, some use air pressure to the suction nozzle, which is much more effective.

Rock screen for suction dredge nozzle