DS901: The Arkiduct Device
Towards axle-less propulsion and delivery

David Noel
Ben Franklin Centre for Theoretical Research
PO Box 27, Subiaco, WA 6008, Australia.

What is an Arkiduct?
The Arkiduct is a new approach to making devices such as ship and airplane engines, and pumps and material-delivery devices, without the use of axles.

An axle is a basic component of the wheel, perhaps the earliest of the devices invented by Man, and has been in use in carts for some 7000 years.

An Arkiduct consists of a rotating hollow Cylinder, with the rotation brought about by a surrounding cradle, sleeve, or harness outside the cylinder. Typically, the Surround will contain magnetic surfaces and be powered by electric current, as in a normal electric motor.

To clarify, let's look at some examples of existing devices, and see how they could be substituted by Arkiduct-based devices. First, let's look at an Archimedes Screw.

In their simple form, Archimedes Screws have been used as water-pumping devices for at least 2000 years, and may go back to the Hanging Gardens of Babylon, one of the Seven Wonders of the Ancient World. The location of these was lost, but recent work [3] indicates that the gardens described were actually at Nineveh, well north of the currently-assumed site of Babylon.

If this is correct, then the Hanging Gardens were built by the Assyrian king Sennacherib (704-681 BC), in his capital city of Nineveh on the River Tigris, near the modern city of Mosul. Sennacherib's creation is well-documented, and images on stone exist of these "water screws".

Fig. DS901-F1. An Archimedes screw. From [1]

How an Archimedes screw works
The Screw contains a helical blade (in a helix shape), which when rotated, pushes the water along the axis.

Fig. DS901-F2.Operation of an Archimedes Screw. From [2]

Its equivalent in Arkiduct form has similar blades, but instead of being mounted on a axle, the blades are fixed to the side of the enclosing cylinder. When this cylinder is rotated, the action is exactly the same, and water is forced along the duct. The axle is no longer needed, and can be eliminated.

The essential parts of an Arkiduct are the Cylinder, the Blades or Thread, and the Surround. The Surround could be a cradle or another form within which the Cylinder can rotate, even another cylinder, and the Cylinder and Surround must contain the electric and magnetic components which cause rotation when current is supplied.

Fig. DS901-F3.Components of an Arkiduct

In essence, the Arkiduct is just a form of electric motor in which the rotating assembly is hollow instead of being on an axle. Or, it can be thought of as a motor in which the axle is hollowed out and unconnected, while the rotor parts are compressed to its outer side.

Fig. DS901-F4. Components of an electric motor. From [4].

The Arkiduct Blades or Thread
The Arkiduct Cylinder typically contains a helical moulding or projection along its inner surface, the nature of which will depend on the intended use. In some cases this helical moulding will be in the shape of a blade, in others it will be much reduced, as in the inner thread of a metal bolt.

The "Thread" can even be negative, as in the case of the rifling inside a gun barrel.

Fig. DS901-F5. Rifling inside a 75 mm gun. From [6]

Or it could be a pairing of single and double helixes, formed with rubber, as in the case of a progressive cavity pump. These pumps will operate on a mix of lumpy solids, as well as on water.

Fig. DS901-F6. Progressive cavity pump From [7]

Possible Arkiduct replacements for conventional applications
Arkiducts may offer better outcomes than comparable conventional devices, but each application needs specific relevant design criteria to be applied. Every Arkiduct needs an electricity supply and windings and magnetics to operate.

We can consider a few examples.

Ship propellors.
Ship propellors or screws have been subject to a lot of development over many years. Conventional designs may suffer from an erosive force called cavitation, which attacks areas round the propellors.

Fig. DS901-F7 The Griffith ship screw. From [5]

Conventional ship screws could be replaced by electrically-driven large-bladed Arkiducts of similar shape. They could also be replaced by longer, helical-bladed ducts, which would sweep water through without cavitation. If pairs of ducts were used, one of each side of the ship's axis, these could be used for steering, by varying the relative flow through each.

If of advantage, duct pairs could run in opposite senses, one clockwise, the other anticlockwise. The threading down a duct could change with its length.

Pumping materials.
Arkiduct pumps should be versatile and adaptable to pump various materials, both fine and coarse solids, such as flour or sand, as well as liquids and mixes such as drilling muds.

Fig. DS901-F8. A push-pump setup used in agriculture. From [8]

Transport and vehicles.
Airflow through Arkiducts could be used to drive vehicles and other transport, such as aeroplanes -- a plane jet engine works this way. In shallow waterways and swamps, airboats may be used.

Fig. DS901-F9. An airboat. From [9]

Electricity generators.
Electric generators are similar in concept to electric motors -- motors feed electricity to a device to produce motion, generators convert motion into electricity in a similar device by the inverse action. Wind generators could be run using Arkiduct rings or ducts, possibly banks of ducts.

Fig. DS901-F10. Wind turbines. From [10]

Similarly, hydro power plants could use Arkiduct turbine generators to generate electricity from water flow. Some modern hydro generators are huge in size, as big as houses, there seems nothing obviously stopping them going axle-less.

Fig. DS901-F10. Hydro turbine. From [11]

It may also be possible to incorporate magnetic levitation technology into Arkiducts, to reduce frictional losses.

Where to from here?
Electric motors and generators were first developed in the 1830s, and now our modern world is everywhere replete with them, all running on axles.

It may be time to look again at some of these devices, and check whether more efficient designs are possible with them, using axle-less Arkiduct technology.

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References and Links

[1]. Archimedean screw hydro turbine. http://www.renewablesfirst.co.uk/hydropower/hydropower-learning-centre/archimedean-screw-hydro-turbine/.
[2]. Archimedes' screw. http://math9harchimedes.weebly.com/archimedes-screw.html.
[3]. Hanging Gardens of Babylon. https://en.wikipedia.org/wiki/Hanging_Gardens_of_Babylon .
[4]. How to Choose an Electric Motor. https://www.galco.com/comp/prod/moto.htm .
[5]. The Griffith Screw. http://himedo.net/TheHopkinThomasProject/ .
[6]. Rifling. http://projects.nfstc.org/firearms/module04/fir_m04_t06_05.htm.
[7]. Progressive cavity pump. http://www.fao.org/docrep/010/ah810e/AH810E06.htm n .
[8]. Comparative performance of three propellor blades used for push pumps. http://www.fao.org/docrep/field/003/ac414e/AC414E04.htm .
[9]. Airboat. https://en.wikipedia.org/wiki/Airboat .
[10]. Wind turbines. http://www.englishecoenergy.com/wind_turbines_blackpool.html.
[11]. Hydro Power Plant. http://www.slideshare.net/AshvaniShukla/hydro-power-plant-59426011 .

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Version 1.0 on Web, 2016 Oct 19.