There are in use many types of combustion apparatus which burn hydrocarbon fuels. Boilers which consume natural gas, LPG gas or fuel oil may be used to heat buildings or produce electricity, while engines which consume petrol, diesel or LPG may be used to obtain motive power. Devices which apply magnetic fields to fuel before combustion are known to improve efficiency and reduce emissions of harmful gases. However there remains a problem of maximising the magnetic field in throughout the chamber in which the fuel or other fluid is treated. If magnets are applied outside the chamber, the gap between opposing magnets is at least as large as the external diameter of the chamber, leading to a reduced field at the centre of the chamber.

It is an object of the present invention to provide a device which can be inserted into a chamber such as a

fuel line or fluid delivery line and which produces a high magnetic field at the centre of the chamber.

According to a first aspect of the present invention there is provided a device for insertion into a chamber, the device comprising at least three magnets arranged radially about an axis and adapted to apply a magnetic field within said chamber.

Preferably said magnets are spaced equidistantly about said axis.

Preferably said magnets are substantially planar, the length and breadth of each magnet being greater than the thickness of the magnet. Preferably said magnets are substantially cuboid in form. Preferably the magnets are arranged such that a first long side is parallel to said axis and a second long side extends radially from said axis. Preferably each face bounded by the first and second long sides is a pole face.

Preferably the magnets are arranged such that a north pole of one magnet faces the south pole of the adjacent magnet.

Preferably the device comprises one or more layers of magnets, each layer comprising at least three magnets arranged radially about an axis. Preferably the magnets in each layer are substantially planar and arranged to be coplanar with the magnets in the other layers. Preferably the orientation of the magnets in each layer is the reverse of that of the magnets in each adjacent layer, such that each north pole of a magnet in one layer is adjacent to a south pole of a magnet in an adjacent layer.

The edge face of each magnet adjacent to the axis may

be profiled to aid interconnection of the magnets. The profiling may take the form of mitring or chamfering on one or both sides of the edge face. Alternatively the profiling may take the form of an arcuate channel extending along the edge face and adapted to engage with a spine member extending along the axis of the device.

In a preferred embodiment there are four magnets in each layer arranged in a cruciform pattern.

According to a second aspect of the present invention there is provided an apparatus for the treatment of a fluid, the apparatus comprising -a chamber having a first end and a second end and a longitudinal axis extending from the first end to the second end, -an inlet and an outlet arranged at the first and second ends respectively, each communicating with said chamber, and -at least three magnets arranged radially about said axis and adapted to apply a magnetic field within said chamber.

Preferably the apparatus comprises a device according to the first embodiment of the invention.

Preferably the chamber is bounded by a casing of impervious material. Preferably the casing is of non- magnetic material, for example aluminium or plastics material.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying figures, where:

Fig. 1 is a perspective view of a device according to a first aspect of the invention; Fig. 2 is a transverse sectional view through the device of Fig. 1; Fig. 3 is a perspective view of an apparatus according to a second aspect of the invention; Figs. 4 to 7 are transverse sectional views through the device of the invention showing different arrangements of magnets; Fig. 8 is a transverse sectional view through the apparatus of Fig. 3 showing the magnetic field strength; Fig. 9 is a transverse sectional view through the device according to a third aspect of the invention; Figs. 10 to 14 are transverse sectional views through the device according to a fourth aspect of the invention showing different arrangements of magnets; and Fig. 15 is a transverse sectional view through the device according to a fifth aspect of the invention.

Referring to Fig. 1 there is shown a device 5 for treatment of a fluid comprising a number of layers of rectangular cuboid magnets. In this case there are shown five layers. The top layer comprises four magnets la, 2a, 3a, 4a arranged in a cruciform pattern.

Each magnet has a north pole at one major face and a south pole at the other major face. The magnets la, 2a, 3a, 4a in the top layer are arranged such that the

north poles face in a clockwise direction when viewed from above.

The second layer from the top comprises four magnets lb, 2b, 3b, 4b arranged in a cruciform pattern. Each magnet in the second layer is arranged to be coplanar with a magnet in the top layer. However the magnets lb, 2b, 3b, 4b in the second layer are arranged such that the north poles face in a counter-clockwise direction when viewed from above, i. e. their polarity is reversed when compared to the top layer.

Succeeding layers of magnets 1-4c, 1-4d, 1-4e each have their polarity reversed in comparison to the adjacent layer.

Fig. 2 shows a section through a device similar to that of Fig. 1. The four magnets 11,12, 13,14 of a layer are shown held in a cruciform arrangement by a tubular casing member 15. In order that the cruciform has legs of equal length so that it fits in a circular cylinder, magnets 12 and 14, which abut each other, are longer than magnets 11 and 13, which each abut magnets 12 and 14 at the joint. In order to make the layers of magnets more stable it has been found beneficial to ensure that in the next layer magnets 11 and 13 are longer and abut each other, while magnets 12 and 14 are shorter.

Fig. 3 shows an apparatus 25 for the treatment of a fluid such as fuel gas, petrol, liquid chemical or blood. The fluid enters a chamber 20 at inlet 23 in end wall 21. Inside the chamber is a device 5 comprising radially arranged magnets. The fluid passes through the chamber within a magnetic field induced by the magnetic device 5. The magnetic field is strongest

at the centre 6 of the device 5, close to the central axis of the chamber 20. The fluid exits the chamber 20 through the outlet 24 in end wall 22. The outlet is positioned in the centre of the end wall 22 on the central axis of the chamber 20, so that the fluid is drawn through the outlet from the centre of the chamber where the magnetic field is strongest. In this way the effect on the fluid is maximised. Although Fig. 3 shows a square-section chamber 20, it is to be understood that other shapes are possible, such as a cylindrical chamber.

Fig. 4 shows a section through a device of the invention having four magnets 30 in each layer. The inner edge surface 31 of each magnet is formed with an arcuate channel which fits around a spine member 33.

In this way all four magnets 30 have the same length.

The outer edge surfaces 32 may be profiled to fit within the chamber or sleeve within which the device is to be fitted. In Fig. 4 the outer edge surfaces 32 are shown with a convex arcuate profile, adapted to mate with the cylindrical sleeve 34.

Fig. 5 shows a section through a device of the invention having three magnets 40 in each layer. The inner edge surface 41 of each magnet is bevelled to form an internal angle of 120°, so that the magnets fit together at a point. In this way all three magnets 40 have the same length.

Fig. 6 shows a section through a device of the invention having eight magnets 50 in each layer, while Fig. 7 shows a section through a device of the invention having sixteen magnets 60 in each layer.

There is no theoretical limit to the number of magnets which may be arranged radially about the axis, although

in practice manufacturing limitations would prevent very large numbers of magnets.

Fig. 8 shows typical values of magnetic flux density within the magnetic field generated by the apparatus of Fig. 3. It can be seen that the cruciform arrangement of magnets 1,2, 3,4 maintains a flux density of at least about 900 Gauss everywhere within the area bounded by lines 70 joining the external edges of the magnets. In contrast the flux density in the centre of the chamber 20 which would be achieved if the same magnets were positioned around the edge of the chamber would be only about 200 or 300 Gauss.

This increase in flux density means that there is an effective reduction in cost, since by placing the magnets in a radial arrangement within the chamber rather than placing them about the perimeter of a chamber, smaller, less powerful and therefore cheaper magnets may be used to achieve the same magnetic flux density.

Figs. 9 to 14 show alternative arrangements of magnets forming the fluid treatment device. In Fig. 9 there are two"nodes"80,81 or axes from which the magnets 82 project radially. Although Fig. 8 shows a circular sleeve 83, the arrangement shown is particularly suitable for sleeves of oval, elliptical or rectangular cross-section. The number of"nodes"could be increased to accommodate pipes or sleeves having a flatter cross-section.

Figs. 10 to 14 show arrangements suitable for pipes or sleeves of larger diameter (not shown). In Figs. 10 and 11 there are four"nodes"90,100 or axes from which the magnets 91,92, 101,102 project radially.

In Fig. 11 spine pieces 105 of plastic are placed along the axes. The polarity of each magnet or of any combination of magnets may be reversed as required. In particular the polarity of each magnet 92,102 forming the central square may be reversed alone or in combination with other magnets 92,102 forming the central square.

In the embodiment of Fig. 12 the magnets 92,102 forming the central square are replaced by a plastic former 112. The remaining magnets 111 may be chamfered at their ends 114 so that they fit together within recesses 113 in the plastic former 112. The plastic former 112 may, instead of having recesses, simply abut the square ends of the magnets 111.

The arrangement of nodes with radial magnets extending therefrom may be extended in any direction, as shown in Figs. 13 and 14, which have plastic spine members 116 at each node where three or four magnets 115 meet.

Similar networks of nodes are possible where three magnets meet at each node, forming triangular voids between the magnets, or where five, six or more magnets meet at each node, forming pentagonal, hexagonal or other polygonal voids between the magnets.

Fig. 15 shows a section through a device of the invention in which a number of arrangements 120, similar to that shown in Fig. 6 but each having 6 magnets 121 instead of 8 in each layer arranged about a point 122, are arranged in a honeycomb pattern within a sleeve 123. The effect is to create primary and secondary node points 124 at which three magnets 121 meet. This ensures that there are no"weak"areas within the sleeve at which the magnetic field is weak because of distance from a magnet.

The individual magnets 1-4,11-14, 30,40, 50,60 are typically rare earth magnets, such as samarium cobalt or neodymium, which are readily available in sizes of up to about 30mm square and 5mm thickness or 60mm by 40mm rectangle and 10mm thickness. It is possible to use other magnets, such as ferrous magnets, ceramic magnets or electro-magnets.

The device consisting only of magnets may be inserted in an existing fuel line, using the existing pipe or tube as a chamber. It could be incorporated into a fuel filter, so that installation is as easy as replacing the fuel filter. It can be made very small using magnets of less than 5mm maximum dimensions. It can find a use in any process treating a fluid having free radicals, such as ionisation of fuel, purification of water or gases such as air and oxygen, treatment of liquid foodstuffs such as beer and detoxification of medical fluids such as blood. However the use of the device is not limited to use with any of the fluids mentioned herein.

These and other modifications and improvements can be incorporated without departing from the scope of the invention.