Does friction loss confuse you? In this video, we demonstrate how friction loss robs you of flow by using two different diameters of pipe on the same pump! Find the perfect pump for your water feature at www.atlantic-oase.com!
Flexible hose doesn't save very much friction even though it eliminates the 90° elbows because internal ribbing on the flexible hose actually makes it a little less smooth than the rigid PVC. In practice, they're about the same.
Hi Jason, Wherever there's water moving through a pipe friction is a consideration. When using the pump outside the body of water, plumbed "inline" or used in a "flooded suction" situation the diameter of the pipe that feeds the inlet of the pump is even more critical At the outlet, friction can be overcome by the force of the pump. It will rob flow and raise operating costs if the sizing is off, but it boils down to the pump having to work too hard for nothing, and the pump will generally underperform but survive. On the inlet side the water is feeding the pump only by the force of gravity. Even small losses of flow due to friction can starve the pump for water. As the pump pushes more water out than can easily flow into it, inlet pressures will drop, and even asynchronous pumps will cavitate as bubbles form in the around the impeller. Spinning in a foam rather than in a solid column of water, the impeller will not encounter the resistance it was designed for. The pump will spin too quickly, and the lower flow around the water-cooled rotor will only make it worse. The motor will overheat and start tripping the internal thermal cutoff. It's just a matter of time before it burns out. To avoid all these dire consequences, eliminate friction in the inlet plumbing by keeping the inlet short, straight and a size larger than the discharge. -Demi
Yes, the difference in the time it takes to fill the bucket is due to the extra friction in the 2-in hose coming out of the same pump into the same bucket.
