Vacuum Pump Ejector|Venturi Pump|3/4 Gardena

V2 is now available: Click the image!

High-Performance Water Jet Pump (Venturi Nozzle) – Optimized for Garden Hose Connection

Self-developed water jet pump that gets maximum performance out of a normal garden tap (approx. 3–4 bar). I invested a lot of time and numerous prototypes to perfect the internal flow. In my tests, the pump sucks up 1 liter of water in just 12 seconds!

• The Perfect Water Jet: The inner nozzle is not just angled, but follows a specially calculated curve (for fluid dynamics enthusiasts: a Witošzyński profile). This ensures that the water does not scatter, but shoots out like a hard, smooth jet.

   

• Distances and Angles: I have optimized the distance between the nozzle and the suction pipe in countless experiments. The angle at which the water exits at the bottom is also calculated so that the flow does not break off and the force is fully maintained.

   

• Smooth Flow: All internal edges and transitions are softly rounded to prevent small water vortices that would only unnecessarily consume energy.

   

• Ready to Use: The thread is a standard 3/4-inch pipe thread. So you can screw the pump directly onto standard Gardena connections or similar without any adapter.

Print Settings & Tips: So that the pump works just as well for you and withstands water pressure:

• Material: PETG or ASA (due to water resistance).
• Orientation: Simply place it upright on the print bed (water inlet downwards). The model is so cleverly designed that you do not need any internal support structures!
• Walls & Infill: Make the part strong! At least 4–5 wall lines. 25% infill is often enough, but if you want to be absolutely sure that everything is completely watertight, print with 100% infill.
• Layer Height: 0.2 mm works, but 0.12 mm (or even finer) is much better! The smoother the inner walls are printed, the better the water flows.

⚠️ For Maximum Performance

The optimum for this nozzle is exactly 3.5 mm in diameter. However, since 3D printers always have minimal tolerances, small pimples on the Z-seam, or material shrinkage, I deliberately made the hole in the CAD model slightly larger (3.7 mm).

For Even More Performance:

Take a cold 3.5 mm metal drill bit and carefully turn it by hand (please without a drill machine!) through the front, inner nozzle tip. This scrapes away tiny print artifacts, calibrates the hole to exactly 3.5 mm, and creates a razor-sharp edge. This small manipulation transforms an uneven water jet into the perfect "laser beam" that this pump needs. (Optionally, you can then carefully clean the lower tube with a 5 mm drill bit).

Have fun printing and experimenting – I look forward to your feedback and your makes!