| US3045599A | 1962-07-24 | |||
| US3241490A | 1966-03-22 | |||
| EP0043066A1 | 1982-01-06 | |||
| EP0115569A1 | 1984-08-15 | |||
| EP0155374A2 | 1985-09-25 |
PATENT ABSTRACTS OF JAPAN vol. 6, no. 155 (E-125)(1033) 17 August 1982, & JP-A-57 78360 (UEMURA KOGYO K. K.) 17 May 1982, see the whole document
PATENT ABSTRACTS OF JAPAN vol. 9, no. 251 (E-348)(1974) 8 October 1985, & JP-A-60 98865 (NIPPON DENSHIN DENWA KOSHA) 1 June 1985, see the whole document
| 1. | An electromagnetic pump comprising a conduit (12; 28) for guiding an electrically conductive fluid medium, means (24, 26; 32, 40) for creating a magnetic field across the conduit, and means (16, 16', 18; 50) for causing movement of the fluid medium relative to the means creating the magnetic field. |
| 2. | An electromagnetic pump as claimed in claim 1 wherein the means for creating the magnetic field comprises a magnet (24, 26) providing magnetic field lines across the conduct (12) and the means for causing the movement of the fluid medium comprises means (16, 16', 18) for causing current flow in the medium in a direction transverse to the magnetic field lines. |
| 3. | An electromagnetic pump as claimed in claim 2 wherein the conduit (12) is of nonconductive material and the means for causing current flow in the medium comprises electrodes (16, 16' ) spaced across the conduit and in contact with medium, and a . c. source (18) connected to the electrodes. |
| 4. | An electromagnetic pump as claimed in claim 3 wherein the conduct (12) is of rectangular cross section, two opposed sides thereof mounting the electrodes (16, 16') internally and the other two opposed sides externally mounting the pole pieces (24, 26) of the magnet. |
| 5. | An electromagnetic pump as claimed in claim 1 wherein the means for creating the magnetic field comprise a pair of electromagnetic coils (32, 40) opposed across the conduct (28) and energizable to have poles spaced along the conduit, and wherein the means x for causing movement of the fluid medium comprises means (50) energizing the pairs of coils so that the polarities of the coils are opposite and alternating. |
| 6. | An electromagnetic pump comprising a conduct (28) for receiving an electrically conductive fluid medium, and electromagnetic means (32, 40) arranged to be energized to create magnetic field lines which extend across the conduct and which move along it, thereby causing the fluid medium to move in the same direction along the conduct. |
| 7. | An electromagnetic pump as claimed in claim 6 wherein the electromagnetic means provides a plurality of poles spaced apart along opposed sides of the conduit and energizing means (50) energizing the electromagnetic means so that each pole alternates in polarity whilst being opposed across the conduit to an opposite pole. |
| 8. | An electromagnetic pump as claimed in claim 7 wherein the electromagnetic means comprises a plurality of pairs of coils (32, 40, 34, 42, 36, 44, 38, 46) located so that the poles thereof are equally spaced along the conduit (28). |
| 9. | An electromagnetic pump as claimed in claim 5 or 8 wherein the conduit (28) is of rectangular cross section, the coils being located externally adjacent opposed sides of the conduit. |
| 10. | An electromagnetic pump as claimed in claim 5 , 8 or 9 wherein the coils comprise threephase windings and the energizing means (50) provides three phase energizing signals to the windings. |
The invention relates to electro-magnetic pumps, that is, pumps in which the medium to be pumped forms part of an electro-magnetic circuit.
According to the present invention there is provided an electro-magnetic pump for an electrically conductive medium, the pump comprising conduit means for transport of the medium, means for developing a magnetic field across the conduit means and means for producing relative movement between the magnetic field and the electrically conductive medium.
According to one aspect of the invention, the means for producing the relative movement comprises electrode means for passing direct current across the conductive medium in a direction substantially perpendicular to the direction of the magnetic field so as to generate a force tending to move the medium.
The means for developing the magnetic field may comprise one or more permanent magnets or electro¬ magnets.
In another aspect of the invention, the means for developing the magnetic field comprises a plurality of electro-magnets and the means for producing the relative movement between the magnetic field and the conductive medium comprises an alternating voltage supply for alternating the polarity of each electro- magnet so as to effect movement of the magnetic field in a direction along the conduit means. The voltage supply may comprise a three-phase supply and each
electro-magnetic means may comprise a three-phase winding assembly.
The conduit means may comprise a non-magnetic, non-conductive pipe, for example a glass fibre or composite material pipe.
The medium to be pumped may comprise an inherently electrically conductive fluid, or a non-conductive fluid to which a conductive medium has been added, for example, a protective additive injected into the fluid so as to impart to it conductive properties.
The invention is described further hereinafter, by way of example only, with reference to the accompanying drawings in which:
Fig. 1 shows a schematic vertical cross-section through a conduit in an electro-magnetic pump embodying the present invention;
Fig. 2 is a schematic horizontal section through the pump of Fig. 1 ;
Fig. 3 is a schematic sectional side view of the conduit of a second electro-magnetic pump embodying the present invention; and
Fig. 4 is a schematic vertical section through the pump of Fig. 3.
The electro-magnetic pump 10 shown in Figs. 1 & 2 is arranged for pumping an electrically conductive medium 14 through a conduit 12 of rectangular, in particular square, cross-section and of non-magnetic material. A permanent magnet is located externally of the conduit 12 with its north-pole 24 and south-pole 26 disposed on opposite sides of the conduit. Electrodes
16,16' are mounted respectively on the upper and lower inner surfaces of the conduit 12 and are connected by respective connection lines 20,22 to a d.c. source 18, so that the electrode 16 functions as a cathode and the electrode 16' as an anode. The circuit containing the
electrodes 16,16' is completed through the electrically conductive medium 14.
Magnetic field lines, indicated by arrows B, B 1 , extend across the conduit 12, generally in the horizontal direction as shown, because of the positioning of the poles 24, 26 of the permanent magnet. The electric circuit comprising the anode 16', cathode 16, connection lines 22, 20, the d.c. supply source 18 and the electrically conductive medium 14* is such that current passes through the medium 14 in the direction, indicated by arrows A, A', orthogonal to that of the arrows B,B'.
The medium 14, which is carrying the current through the magnetic field, experiences a force according to Fleming's Rule and to the equation: F = B x I x 1 where F is the force, B the magnetic flux density and 1 the common length, axially of the conduit 12, of the poles 24,26 and the electrodes 16,16', corresponding to the length of the column of the conductive medium within the magnetic field.
Accordingly, the force tends to move the electrically conductive medium along the conduit 12.
The force thereby developed acts to produce a pressure differential within the flow path in the conduit 12.
Fig. 2 shows the direction of the force, indicated by arrow Fp, experienced by the medium 14 and the direction in which medium consequentially flows through the conduit 12. Although Figures 1 & 2 show only one permanent magnet 24,26 and one pair of electrodes 16,16', the pump 10 may comprise a plurality of such magnets and a
" further plurality of such electrodes located along the length of the conduit. The pump of Figures 3 & 4 comprises an elongate
conduit 28, again of non-magnetic material and of rectangular cross-section, having on opposed sides a series of mutually . opposite pairs of three-phase windings or coils 32-38 and 40-46. A three-phase voltage supply V1 from a source 50 drives the electro¬ magnetic coils 40-46 and a similar supply V2 from the source drives the electro-magnetic coils 32-38.
The nature of the coils 32-46 and the phase of the voltage supplies V1 and V2 are such that at any one time the poles of the coils 32-38 are opposite in polarity to those of mutually opposing coils 40-46. Thus, during one particular half cycle, as illustrated in Fig. 3, a series of magnetic field lines C and D are developed across the conduit 28. The voltage supplies V1 and V2 are coordinated so as to alternate the polarity of the coils 32-40 such that during the next half cycle from that illustrated in Fig. 3, the polarities of each coil are reversed. This continual reversal of the polarities, provided by the voltage supplies V1 , V2, gives the effect of the magnetic field lines progressing along the conduit 28, in the direction of arrow E in Fig. 3.
The velocity V of this apparent movement of the field lines is given by: V = 2 x T x f where T is the pole pitch of the coils and f the frequency of the supply voltage signals. Because Fig. 4 is a vertical section through the conduit 28 of Fig. 3 the magnetic field lines would travel into the Fig. 4 drawing.
The relative movement between the magnetic field lines C, D and the electrically conductive medium 30 v seeks to induce an electric current into the conductive medium. However, in accordance with Lenz's Law, a back electro-motive force (Back-EMF) will develop in the
electrically conductive medium 30 and, in combination with the magnetic field lines, will act so as to create a force in a direction to move the electrically conductive medium 30 in the same direction as the moving magnetic field lines, that is, in a direction to reduce the relative movement between the medium 30 and magnetic field lines C, D, which is the relative motion tending to generate the electric current. The force experienced by the medium 30 and created by the back EMF thus causes the medium to move along the conduit in the same direction as the moving magentic field lines.
Although only four pairs of electro-magnetic coils are illustrated in Fig. 3, any suitable number of pairs could be provided corresponding to the length of the electro-magnetic pump required.
The invention can be embodied in a variety of ways other than as specifically described and illustrated.