What are the main differences between a closed vane impeller and a open vane or (vortex impeller) and when are each recommended?
Closed vane impellers are the most common used on dredge pumps and the vanes have sides on both ends to totally enclose the vanes. This creates closed channels from the eye of the pump to the periphery or the runner or impeller. Some pumps are three vane allowing larger particles to pass and some pumps are four vane. The increased vane increases the pump head but further restricts particle size. These impellers are excellent for silt, all grades of sand, and also gravel within limitations. Open vane or vortex impellers are designed to have the vanes open to the eye of the pump and are generally recessed into the pump casing. The energy is created by the spinning of the slurry in front of the impeller. They are excellent for viscous sludges such as sewage sludges and will dissipate gasses in the slurry without cavitation. Most vortex pumps are generally submerged so that the eye of the pump is very close to the cutter feeding the pump. The submerged pumps on horizontal auger dredges gen
