Supa-Stelth Pump Explanation
The radical Stelth pump displaces water employing a high-speed “Solid Body Vortex”. Strobing “sails” (“tell-tales”), embedded within the vortex, reveals the water does not “shear”. Molecular diffusion, at 1493 metres per second (sonic for water) smooths pressure Hluctuations and turbulence, virtually instantly. Diffusion also ejects vortex peripheral water across an invisible dynamic wall into a decelerating body of water functioning similarly to the diffuser of a conventional volute pump.
Having no cutwater eliminates noisy water wake collisions. One manufacturer measured 9dBA noise reduction, 8 times quieter than competitors. It is the only pump where two extremely different speeds of water co-function.
Repeatedly passing through a short window forms the disc shaped vortex; the only hard surface the vortex contacts. The vortex cannot enlarge, distort or thicken due to extremely high speed. 57 revolutions per second gives 29 metres per second of the vortex periphery.
Solid body vortex water molecules line up like wheel spokes thus the vortex periphery goes 10 % to 20% faster than the impeller periphery despite a slightly lower vortex RPM due to vortex lag.
Applications of the Stelth pump employing conventional motors include agriculture, rural, cross-country, pools/spas, bilge, automotive, marine, aeronautical, most industrial and domestic and solar powered.
High RPM.
A smaller diameter Stelth impeller, at 4,000 to 6,000 RPM, generates very high pressure and efHiciency.
The Stelth pump has demonstrated the highest of all “litres per watt hour” and has exceeded the European “MEI” (Minimum Energy Index) highest standards.
High-speed applications include high lift or extreme head resistance, long pipes with many elbows, high-rise buildings and where noise and space/footprint is critical.
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Terry Day is a published author in Aerospace and pump magazines/books. He is a member of the American Institute of Aeronautics and Astronautics and the International Society of Automotive Engineers (SAE).
Water vortex cannot grow in diameter or thicken due to very high speed. The test results show a significantly higher Best Efficiency Point (BEP) than
conventional pumps, which varies depending on particular applications.
Freely rotating “sails” are strobed through a clear pump casing. The sails set relative to each other demonstrating that there is no shear between the water molecules.
From the Koller brochure. Red curve is the Stelth pump.
At the same system resistance as competitors, the Stelth delivers more litres per watt-hour, the indicator of electricity saved. This is more important than merely best
efHiciency point (BEP) because BEP is merely one point on a pump curve.
The Stelth efHiciency curves are much broader, showing better energy efHiciency for changing system resistance such as in Hiltration for pools, industrial, automotive engine
cooling and bilge applications and the fact that most pumps seldom run at their BEP.
A further exclusive Stelth Pump advantage
Higher RPM than induction motor speeds, at very small diameter, delivers even larger increases in performance.
Centrifugal pumps run at speeds controlled by alternating current frequency from the power station, 60 cycles (60 Hertz) 3,600 RPM. As pump impeller speed signiHicantly increases over conventional speeds, water wakes collide with the cutwater of a volute pump or the diffuser inlets of a pool pump thus resulting in cavitation with loss of efHiciency and extreme noise. Large pumps use 4 and 6 pole motors to reduce RPM.
The Stelth pump has no cutwater or diffusers. In small versions, it can run at extremely high RPM with efHiciency, pressure and output increasing as the RPM increases. At 6000 RPM it is barely audible. Conventional centrifugal pumps will never be able to do this even with higher RPM motors. A single stage Stelth can replace multi-stage pumps.
A second reason for limiting RPM of conventional pumps is that induction motors run at compromise speeds, dictated by the power stations, for a reason. 50 cycles gives 3,000 RPM in Europe and much of Asia and 60 cycles, 3,600 RPM in USA.
This worldwide compromise is because the iron in the motors cannot switch magnetic polarity much faster than that and is also subject to hysteresis losses. That is why motors and many appliances, such as pumps, have grown up together.
The Stelth high RPM advantage has been trialled at a leading Australian University powered by a new, high RPM, Amorphous Metal Motor. Amorphous iron, used in the world’s most efHicient transformers, can switch polarity extremely fast and reduce losses over conventional iron by ten times with the highest efHiciency achievable and is now being developed as a motor, a 30 year long dream.
The best quality Amorphous iron is made by Metglas, wholly owned by Hitachi Metals America. The Metglas website explains the advantages of amorphous iron over standard iron. These advantages will now begin to apply to motors and generators.
Geometric rules favour the Stelth pump. If you decrease the size of any object, the surface area increases relative to its internal volume. The surface area of pump A below, relative to its internal volume, is 74% larger than the surface area of pump B relative to its internal volume. Extremely large pumps cannot Hind enough outer surface for in and out ports so must have double inlets, which means an inlet each side.
Smaller size gives the Stelth a favourable advantage for larger surface to volume ratio.
Larger “recession” of a smaller impeller gives an advantage for pressure and efHiciency.
For same water speed for pumps A and B,
• ”a” is less distance than “b”. Water is accelerated through a shorter distance.
• “c” is further than “d”. This is a greater acceleration off the impeller.
Acceleration is the source of all force. Larger acceleration results in larger force.
Cost of variable speed BLDC motors is largely offset by the lower cost of the small size Stelth pump running at high RPM and the physically smaller motor. Far lower running costs re-coup investment quickly. It enables a tiny, energy dense package. This also means that running small Stelth pumps in parallel and or series has great advantages.
6,000 RPM equals water vortex speed of nearly 100 revolutions per second yet noise is negligible.
4 small plastic Stelth pumps can replace a much larger pump that must be cast from metal, requiring a foundry, impeller balancing and large, high-speed seals and bearings.
The Stelth pump and any motor driving it can be smaller, lighter, quieter, higher pressure and efHiciency and lower cost to manufacture. Almost all categories the Stelth pump has been applied to so far averages approximately 30% increase in “energy efHiciency” indicating the same percentage reduction in dollar cost to run.
The Stelth concept is the biggest breakthrough yet in water movement. It outperforms other pumps while employing conventional induction motors and in addition, introduces the ability to run at very high RPM, employing BLDC variable speed motors, delivering high speed, low noise performance that no conventional pumps can match.
Applications : Industrial, Domestic; for vacs, washing machines, dish washers, Military, including for Stelth-quiet running, Marine generally including bilge, Aeronautical and Aerospace for efHiciency and low weight, Automotive engine cooling, Pools and spas for energy efHiciency and negligible noise, Rural and replacing multi-stage bore pumps, Cross country from Dams, Rivers; Irrigation. And almost any others you can think of!
The Stelth technology may enable global electricity savings of billions of dollars, enable efHicient solar running for pools, domestic and low cost renewable solar powered agriculture and rural applications globally and postpone energy distribution upsizing.
