General > General Technical Chat
Why is the curvature of pump rotor blades "backwards"?
Ground_Loop:
That is not a centrifugal pump as they say in the first sentence. An axial flow impeller is a screw or propeller impeller as they also describe. Centrifugal force is orthogonal to the axis of rotation and is, again, radial.
beanflying:
In the industry they fall under one on the THREE types of typical Centrifugal Pump impellers in use. If you want the industry to change because you demand it then good luck with that ::)
There is also in addition to those the types a bunch of application specific ones I have left out as they are for process, chemical or waste/sewage applications.
The bottom line for the OP still is a Centrifugal Pump for oil is not really the best solution before we get to far away from that.
amyk:
--- Quote from: beanflying on October 01, 2021, 01:12:02 am ---The bottom line for the OP still is a Centrifugal Pump for oil is not really the best solution before we get to far away from that.
--- End quote ---
This. There's a reason nearly all oil pumps (except possibly the huge ones in industrial plants) are vane, gear, or gerotor types. If you're 3d-printing one, a gear pump would probably be easiest.
NiHaoMike:
--- Quote from: beanflying on October 01, 2021, 01:12:02 am ---The bottom line for the OP still is a Centrifugal Pump for oil is not really the best solution before we get to far away from that.
--- End quote ---
My application needs a good amount of flow but not much pressure, quite a different case from most oil pumps with relatively low flow but high pressure. The oil is farm grade mineral oil (often used to cool amateur radio dummy loads), not specified for viscosity but much thinner than car engine oil.
beanflying:
--- Quote from: amyk on October 01, 2021, 01:48:17 am ---
--- Quote from: beanflying on October 01, 2021, 01:12:02 am ---The bottom line for the OP still is a Centrifugal Pump for oil is not really the best solution before we get to far away from that.
--- End quote ---
This. There's a reason nearly all oil pumps (except possibly the huge ones in industrial plants) are vane, gear, or gerotor types. If you're 3d-printing one, a gear pump would probably be easiest.
--- End quote ---
The reason not to go for a gear pump here is tolerance and wear on the sides and faces of the gear with 3D printed bits. And blip or bump on a surface is a grab point. Also extra complexity with needing a second shaft. Some of this can be overcome with installing very thin shims of maybe Teflon or Brass on the sidewalls for the 3D printed Gears to run against but you still have gear to gear mesh wear.
Vane as I offered initially makes a lot of sense and will be fine with mineral types of oil. Use the same thoughts as the gear with a thin shim on both sides of the case. It is also 'normal' on smaller vane pumps to leave the impeller floating on the shaft to align with the cases so depending on the motor a keyway and a slightly loose fit will work.
For seals Nitrile lip seals should be ok but maybe Viton if you can source them for not a lot more is a good idea. You can also go a full mechanical seal but it adds to the size and complexity.
More width = more flow and diameter is proportional to pressure both will increase with speed is a 'sort of' linear fashion minus some slip.
For info
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