Dynamic Pump (Centrifugal)

Final (likely) evolution of my attempt at creating a printable water pump. This pump is a dynamic pump, as opposed to my previous positive-displacement pumps, and performs much better. It also does not require sealing with a 3D pen to allow for disassembly. With the forward facing blades, I would conservatively estimate the free delivery of the pump at 1500~1700rpm to be greater than 25GPM based on eyeballing a 5 gallon bucket (very scientific), but I have not performed any true flow tests or tested shutoff head. This may be updated in the near future. As a note, the pump must be mostly submerged to operate as the pump cannot create enough suction to pull from a hose. 
 

NOTE: Print only one impeller. Tested with forward facing blades but originally designed for rear; forward facing blades should increase pressure as rotation speed increases which is why I made the switch. 

PRINT/BUILD INSTRUCTIONS:

1. Print all parts in 0.10mm layer height with 15% infill, 4 perimeters, and supports for enforcers only. (3mf included with all print settings, skip to step 4 if using)
2. For supports, enforce the raised bottom of the impeller and the curved bottom edges of the pump outlet.
3. For infill, set the driveshaft to print with 100% rectilinear.
4. Place the chosen impeller into the lower housing and attach the input shaft to the impeller through the bottom of the housing.
5. Place one spacer over each of the 4 central legs of the bearing housing, then press the 4 legs into the holes in the bottom of the pump housing to secure the shaft, ensuring the water pickup aligns with the port in the outlet. (SHOWN IN PICTURES 3/4)
   1. Note: scaling the Z dimension of the spacer in your slicer may be beneficial to reducing friction if the driveshaft fits too tight; if the bearing is difficult to spin, increase the height in 0.10mm intervals. Unlock the scaling to ensure that the XY dimensions are unchanged.
6. Place the gasket on the lower housing and carefully slide the upper housing on. This will require a good alignment to allow the arms to slide over the housing. 
   1. Note: the gasket height may be reduced or completely removed if desired; the housing was designed with a slight Z gap but for initial testing I wanted to give more room between the two until I knew how it behaved. 
7. Insert and tighten zip ties in each of the 7 holes situated around the pump housing. An optional 8th zip tie can be used around the outlet, but is not strictly needed, especially if an outlet hose is attached. The pump was designed with a printed piping system in mind so the OD of the outlet may not perfectly line up to commercially available hoses, however, a 1in ID soft tube should be able to slide over the end with a little motivation.
8. Press the inlet funnel into the opening on the upper housing and the pump is complete! Drive the pump with a 1/4in square drive and be sure not to run at excessive speeds without fluid flow; this could cause the bearing to overheat and fail. 

Any feedback will be investigated and appreciated.