GB2362026A

GB2362026A - Laminar flow cable

Info

Publication number: GB2362026A
Application number: GB0010659A
Authority: GB
Inventors: Mark William Goldney Baker
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-05-04
Filing date: 2000-05-04
Publication date: 2001-11-07
Also published as: GB0010659D0

Abstract

A laminar flow cable comprises a signal conductor forming a flexible hollow shaped tube 1 and a return conductor forming a flexible hollow shaped tube 6. The conductors are comprised of conductor strands 3. These are laid upon an insulation former 2. The strands may be covered by a conducting plastic sheath 4 to ensure electrical contact around the cross-sectional circumference. The layer 4 is covered by an insulating sheath 5 which not only act as an insulator but also act as a spacer between the conductors. The conductors may be arranged concentrically which has the advantage of reducing RF interference. The cable minimises electromagnetic interference and electrical vibration interference of neighbouring strands. The arrangements also aid skin effect, since the conductor forms a relatively large circumference of thin cross-sectional area.

Description

2362026 Laminar flow cable A conducting cable for electricity (ac or de)

with end connections oriented such that both the signal and return paths (or positive and negative current paths) for any electrical item consists of a conductor or conductors forming a flexible hollow shaped tube (or tubes) in which electrical continuity is maintained around the cross-sectional Circumference of the tube.

There are countless electrical cables on the market but none that optimally solve the highly complex aspects of conducting an electrical current with minimum electrical vibration interference and electromagnetic interference from neighbouring strands of the same conductor for both outgoing and inbound portions of the current path. Before proceeding further the term "electromagnetic interference" should be understood to refer to the phenomenon that all metals (including copper) have a magnetic signature that can cause eddies and other effects in the flow of electricity. Metal adjacent to an electrical current affects the flow of electricity to varying degrees - the energy required to constantly magnetise metal in neighbouring strands of a conductor (however minute the effect) causes aberrations m the perceived performance of a cable particularly the audio quality. It should further be stated that the term "metal adjacent to" may include the conductor or strand itself - because of skin effect more current may be flowing on the outer skin of a metal than on the inner core which leads the the inner core being effectively "metal adjacent to" the current. Electromagnetic interference also refers to the phenomenon that each strand of a conductor has it's own electromagnetic field surrounding it when strands are grouped together all these individual fields interfere with one another. Secondly the tenn "electrical vibration interference" refers to the phenomenon that neighbouring strands vibrate minutely when passing an electrical current. This vibration against neighbouring strands causes electrical discontinuities which create aberrations in the perceived performance of a cable. As a consequence the lower the number of adjacent strands in contact with any strand, the lower the electrical interference. With this invention the number of adjacent strands in electrical contact with each strand is minimised to 2 in the best case with stranded conductor or none in the case of foil.

Definition of terms - to help clarify points in this description, the terms used can be defined as follows

0 "Cable" is the entity comprising conductors for both signal and return electrical path (or positive and negative conductors) including it's connectors and the way in which they are wired - The connection orientation determines the characteristics of a cable Wire" is the same as cable but without end connectors attached "Conductor" is the group of strands, foil or foils that together form a conduction path for the electrical current Strand is an individual wire that alongside others makes up a conductor.

"Solid form conducto?' may not only refer to a solid conducting material but also to a section packed with conducting strands or similar.

"Connecto?' is the mechanism or device used to connect the conductors to equipment.

"signal" and "return" can apply not only to signal currents but to any current path including alternating current or dc current. For the purpose of this patent these words can also mean positive and negative for dc applications or live and neutral for alternating current.

An object of this invention allows effective conduction to take place whilst fulfilling the following aspects 2 a) Minimising the electromagnetic interference and magnetic signature effects of neighbouring strands (or ribbons) in the same conductor. This must be seen in the context of balancing other requirements. b) Aiding skin effect beneficially, via a hollow section conductor that forms a relatively large circumference of thin cross-sectional area. This does not have the disadvantages of a solid form of conductor's internal magnetic signature.

Accordingly this invention provides a conducting cable for electricity (ac or dc) with end connections oriented such that both the signal and return paths (or positive and negative current paths) for any electrical item consists of a conductor or conductors forming a flexible hollow shaped tube (or tubes) in which electrical continuity is maintained around the cross-sectional circumference of the tube.

In view of the enormous number of cables on the market and the fact that some may appear at first sight to embody the idea of the Laminar flow cable it is worth highlighting the differences that exist to those bearing the closest resemblance - for example a twin co-axial cable could be configured as a lammar flow cable by using the outer screen to conduct the outgoing current on one wire and the incoming current on the other outer screen. The answer to this observation is simply that these cables are designed to be (and are in practice) always connected such the inner conductor acts as the current conductor for one direction and the outer circular screen 1 conductor carries the current travelling in the opposite direction. The laminar flow cable is distinguished in this case by the way in which it is configured at the connecting points ie it is configured such that an outer hollow circular screen carries the current travelling in BOTH directions.

Another example of a "cable" close in principle to the Laminar flow cable could be said to be the copper tracks on a PCB board. The difference here is twofold - firstly they are not flexible and secondly flat sections of conductors (as in PCB tracks) have good surface area for the benefits of skin effect but their electromagnetic field pattern is totally different to a hollow tube shape. They suffer from the same phenomenon as solid section conductors - namely that of magnetising much more adjacent material i.e. the top magnetises the bottom and vica-versa. Another example of a "cable" close in principle to the Laminar flow cable could be said to be a co-axial cable in which the centre conductor strands are sheathed with a conductive sheath of hollow section. The difference here to the Laminar flow cable is that the conductive sheath is still in electrical contact with the centre conductor strands and thus effectively comprises a "solid form conductor" with conductive material at it's centre.

Preferably the cable is made of any type of conductor and insulator.

A preferred embodiment of the invention will now be described with reference to the accompanying drawing m which:

FIGURE 1 shows a "dumbbell" configuration ofthe cable FIGURE 2 shows a concentric configuration of the cable As shown in Fig 1, the cable comprises a signal conductor 1 and return conductor 6 in "dumbbell configuration". The conductors are comprised of conductor strands 3. These are laid up on an insulation former 2. The strands 3 are covered by a conducting plastic sheath 4 to ensure electrical contact around the cross-sectional circumference. The layer 4 is covered by an insulating sheath which not only acts as an insulator but also as a spacer for the return wire thus ensuring the desired capacitance and inductance characteristics.

3 A variation of the laminar flow cable shown on Fig 1 is shown in Fig 2. All the numbered items of this cable are the same as in Fig 1. This cable configuration has the advantage of reducing RF interference.

4

Claims

1. A conducting cable for electricity (ac or dc) with end connections oriented such that both the signal and return paths (or positive and negative current paths) for any electrical item consists of a conductor or conductors forming a flexible hollow shaped tube (or tubes) in which electrical continuity is maintained around the cross-sectional circumference of the tube.

2. A conducting cable as claimed in claim 1 where the signal and return paths consist of spiral wound copper strands or foil, in which adjacent strands or foil are in electrical contact with one another to form a hollow section with electrical continuity around the cross-sectional circumference (or perimeter) of the section.

3. A conducting cable as claimed in claim 1 or claim 2 where the tubular strand (or foil) formation is further covered overall by a layer of conductive material to ensure continuous electrical contact between ad acent conductors. j

4. A conducting cable as claimed in any preceding claim in which the ends of the signal conductor (with tubular shaped cross-section) are connected to the signal nodes of connectors and the ends of the return path conductor (with tubular shaped cross-section) are connected to the return nodes of connectors.

5. A conducting cable as claimed in any preceding claim which is flexible and does not need to be bent.

6. A conducting cable substantially as herein described and illustrated in the accompanying drawings.