Vacuum Pump Ejector|Venturi Pump|3/4 Gardena

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

Self-developed water jet pump that extracts maximum performance from a standard garden faucet (approx 3–4 bar). I invested a lot of time and numerous prototypes to perfect the internal flow. In my tests, the pump siphons off 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 flow nerds: a Witošzyński profile). This ensures that the water doesn't scatter, but shoots out as a hard, smooth jet

   

• Distances and Angles: I optimized the distance between the nozzle and the suction pipe through 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 consume unnecessary energy

   

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

Print Settings & Tips For the pump to work just as well for you and withstand water pressure:

• Material: PETG or ASA (due to water resistance)
• Orientation: Simply place upright on the print bed (water inlet facing down). The model is cleverly designed so that you need no 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 imperfections at 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 rotate it by hand (please no power drill!) 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 action transforms a turbulent 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 makes