Abstract:
Apparatus, system and method precisely, quickly control flow of molten metal to metal-casting apparatus by pumping, braking or throttling. The Faraday-Ampère principle of current flow in a unidirectional magnetic field is employed. Permanent magnets comprising neodymium or similar high-energy, rare-earth materials provide “reach-out” magnetism. These neo-magnets, usually shown as cubes, are arranged in various powerful configurations driving intense unidirectional magnetic field B across a non-magnetic gap many times larger than economically feasible otherwise. This gap accommodates a conduit for pressurizing and moving a flow of molten metal. In making multiple identical castings, a controlled, intermittent, predetermined flow of molten metal is fed to a series of identical individual molds. The invention obviates needs for operating metallurgical valves or expensive tilting mechanisms for metallurgical furnaces. Existing furnaces too low to permit inflow by gravity may be rendered usable by embodiments of this invention.

Description:
FIELD OF THE INVENTION 
     The invention is in the field of casting of metals, specifically, the electromagnetic transferring of molten metals in the manufacture of metallic articles by casting, for example, by continuous metal-casting machines. And, for example, by periodically transferring measured, metered, controlled and/or predetermined quantities of molten metal into casting apparatus involving a succession of identical molds for producing a sequence or series of substantially identical metal castings. Novel methods, system and apparatus embodying the invention employ permanent magnets having reach-out magnetic fields to electromagnetically transfer, brake, measure and control the flow of molten metal. 
     BACKGROUND OF THE INVENTION 
     The need for controlled flow of commercial quantities of molten metal is critical in the casting of metals in various kinds of casting apparatus in order to prevent either overflows or insufficiencies. For example, continuous controlled flow is advantageous for matching the flow rate of molten metal to the speed of a metal-casting device or machine into which the molten metal is being fed on a continuous basis. In the prior art, expensive tilting furnaces, launders, and servo controlled stopper rods are used. However, response to control signals in the prior art has been relatively sluggish, and maintenance may be costly. Moreover, each stopping of a continuous-casting operation may involve the dumping and remelting of much molten metal. 
     Smith et al. in U.S. Pat. No. 5,377,961 disclosed a device for ejecting small drops of solder onto a circuit board. Their device operated on a principle which goes back to Michael Faraday and Andrè-Marie Ampère in the early nineteenth century. Faraday&#39;s three-dimensional three-finger rule of induced electromotive force is exemplified also in the windings of electrical-machine rotors. This principle also is known as the Ampère-Lorentz law. 
     L. R. Blake and D. A. Watt, in their separate articles referenced above, describe pumps of similar principle used for pumping molten sodium or potassium as coolant through cores of atomic reactors. In their pumps, the electromagnet was very large and expensive and used an enormous flow of electrical current. Around 100,000 amperes were required to pump 2,000 gallons a minute of such very light liquid metal (Watt, pp. 98, 95). 
     Bykhovsky et al. in U.S. Pat. No. 5,009,399 used the Faraday principle. Their pressurizing zone was a disc-shaped, axially thin, circular cylindrical cavity in which molten metal was induced to swirl. An electromagnetic “solenoid” without moving parts was the source of unidirectional magnetism through the thin dimension of the cylindrical cavity. 
     Electromagnets and ordinary permanent magnets are drastically diminished in their magnetic flux density by an obstacle of even a small non-magnetic gap placed in their magnetic circuit. 
     SUMMARY OF THE DISCLOSURE 
     My methods, system and apparatus embodying the present invention are applicable for electromagnetically impelling, transferring, braking, measuring and/or controlling the flow of substantial quantities of molten metal through a pressurizing conduit. Such flow of molten metal can be toward or into any suitable casting apparatus, for example, such as a continuous controlled flow into a continuous metal-casting machine as illustratively shown in FIGS. 1 and 1A. Also, such flow can be, for example, a periodic transfer of measured, metered, controlled and/or predetermined quantities of molten metal into suitable casting apparatus involving a succession of identical molds for producing a sequence or series of identical metal castings. 
     The Faraday-Ampère principle is employed, in the motor mode, by which electrical energy is converted into mechanical energy for usage most characteristically as a pump. The mode of operation is readily reversible for serving as a brake or throttle. 
     The prohibitive cost and huge bulk of an electromagnet for attaining the requisite magnetic excitation to bridge a large gap in the magnetic circuit is avoided by the use of permanent, high-energy “neo-magnets” consisting of magnetic material which comprises a rare-earth element, for example such as neodymium. I have calculated that the coils themselves, i.e. the magnet-wire windings, of the most efficient configuration of an electromagnet of equivalent capability to that of rare-earth-containing, high-energy, permanent neo-magnets would occupy about 130 times the volume that are occupied by the neo-magnets. Moreover, the neo-magnets do not generate waste heat, whereas an electromagnet would generate considerable heat, due to passage of large amperage through electrical resistance of its windings. 
     The “reach-out” capability of the neo-magnets positioned, oriented and arranged in specifically configured assemblies as shown and described enable, for the first time, an economically feasible, precise control of the flow of commercial quantities of molten metals. Such precise control makes possible the starting or stopping or adjusting of molten-metal flows almost instantaneously. There are no moving parts. The molten-metal flow area is enclosed, or is protected by an inert atmosphere and hence the flow avoids turbulent and corrosive contact with the atmosphere. 
     The method, system and apparatus optionally include an electromagnetic flowmeter. This flowmeter employs the Faraday principle in the generating mode, by which mechanical energy is converted into electrical energy. Thus, output of an electrical sensor indicates molten-metal speed and may be used to control pumping dynamics. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings, open arrows labeled B represent an intense magnetic field having an axis of unidirectional magnetic flux. Open arrows labeled I represent the axis of direct current shown flowing from “+” to “−” in several Figures. Open arrows labeled M represent the direction of molten-metal flow in the pumping mode; and open arrows P represent travel of frozen product. 
     Corresponding reference numbers and letters indicate corresponding elements, members and/or components in various Figures. 
     FIG. 1 is an elevation view showing an electromagnetic pump embodying the invention and arranged to pump molten metal upwardly from a furnace to a continuous belt metal-casting machine as one example of a casting device which may be used to advantage in cooperation with such an electromagnetic pump. 
     FIG. 1A is like FIG. 1 except that the conduit from the pump to the continuous casting machine is largely omitted. In this FIG. 1A, the molten metal is shown being propelled upwardly in the form of a free, unconfined, parabolic-arch jet-fountain-stream moving through a protective inert atmosphere. 
     FIG. 2 is a perspective view of a molten-metal pump embodying the present invention. The pump apparatus is seen from a viewpoint looking downward obliquely from above and upstream. Shown mainly in dashed outlines are four high-energy permanent neo-magnets—two in a paired arrangement above and two in a paired arrangement below the molten metal flow M, as shown more clearly in FIG.  2 A. Each pair of magnets is shown assembled in FIGS. 2 and 2A with a respective tapered pole piece whose pole face is aimed toward the molten metal flow M. 
     FIG. 2A is a front elevation view of the pump shown in FIG.  2 . For clarity of illustration, FIG. 2A shows only the neo-magnet assemblies, with their pole pieces retained in the non-magnetic shells or jackets and the soft-ferromagnetic frame. 
     FIG. 3 is a perspective view of a pressurizing conduit and associated components in the molten-metal pump apparatus of FIG. 2 as seen looking downwardly obliquely from above and upstream. 
     FIG. 3A is a perspective exploded view of the pressurizing conduit of the pump in FIG.  2  and associated components as seen obliquely from above and upstream. This view shows elements associated with pump electrodes and with speed-sensing electrodes. Vertical lines of unidirectional magnetic flux B are indicated by small crosses. 
     FIG. 4 is a perspective view of a concentrative, high-flux-density molten-metal pump embodying the present invention, as seen obliquely from above and looking downstream. A partial cut-out reveals an upper cooling cell and a thinned portion of a pumping conduit. For clarity of illustration, upper and lower assemblies of high-energy neo-magnets and their respective pole pieces are not outlined in this view. 
     FIG. 5 is a plain view of the pressurizing conduit of the molten-metal pump shown in FIG.  4 . Vertical lines of unidirectional magnetic flux are seen generally in cross section and are indicated by small crosses. 
     FIG. 6 is a perspective, sectioned and exploded view of the pressurizing conduit of the concentrative, high-flux-density molten-metal pump shown in FIG. 4, seen from the same viewpoint as in FIG.  4 . Additionally, four speed-sensing electrodes are shown. 
     FIG. 7 is a perspective view of a quintuply concentrative, high-flux-density neo-magnet assembly which is employed in the molten-metal pump shown in FIGS. 4,  5  and  6 . FIG. 7 is seen from the same viewpoint as in FIGS. 4 and 6. For clarity of illustration, inert filler blocks, which are shown in FIGS. 9 and 10, are omitted from FIGS. 7 and 8. 
     FIG. 8 is a perspective, exploded view of the neo-magnet assembly shown in FIG.  7 . 
     FIG. 9 is a perspective view of the neo-magnet assembly of FIG. 7 showing in dotted outline magnetically inert supportive filler blocks which are included in the assembly shown in FIG. 7, but which were omitted from FIG. 7 for clarity of illustration. 
     FIG. 10 is a perspective, exploded view of the elements in the assembly shown in FIG.  9 . 
     FIG. 11 is a sectional elevation view taken through the apparatus of FIGS. 4,  6  and  12  along the plane  11 — 11 . 
     FIG. 12 is a plan sectional view taken along the plane  12 — 12  in FIGS. 11 and 13 for showing a laminated cooling unit which protects the neo-magnets from heat. 
     FIG. 13 is a partial side view of the elements shown in FIG. 12, as seen from the position  13 — 13  in FIG.  12 . 
     FIG. 13A is a perspective view of a triangular pole piece with its three surrounding magnets. Its end magnet is shown in exploded relationship. 
     FIG. 13B is a perspective view of a hexagonal pole piece with its six surrounding magnets. Its end magnet is shown in exploded relationship. 
     FIG. 13C is a perspective view of a circular pole piece in its unitary ring magnet aid its end magnet shown exploded. 
     FIG. 14 shows the hysteresis loops of magnetization and demagnetization of rare-earth-containing, high-energy, permanent neo-magnetic material compared with alnico 5 permanent magnetic material. 
     FIG. 15 is an elevation view of a convenient test setup. 
     FIG. 16 illustrates the reach-out attraction force capability of “reach-out” neo-magnets exerted through a relatively large non-magnetic gap as compared to the rapid, undesirable decrease of attraction force exerted by alnico 5 magnets through the same non-magnetic gap. 
     FIG. 17 is a perspective view from above of a long triple-input magnetic configuration. The end magnets are shown in exploded relationship. 
     FIG. 18 is a perspective view showing another embodiment of the invention including two cubical assemblies of eight neo-magnets each. The pressurizing conduit and two pancake coolers are shown positioned between these two cubical assemblies of neo-magnets. 
     FIG. 19 is a front elevational view of the embodiment of FIG.  18 . FIG. 19 shows a rectangular ferromagnetic frame associated with the two cubical assemblies of neo-magnets. This frame is omitted from FIG. 18 for clarity of illustration. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The purpose of the described electromagnetic pumps  32 ,  32 G (FIGS. 2,  4 ) is to impel or restrain the flow of molten metal toward, or into, a mold or a metal-casting machine. 
     Embodiments of the present invention may, for example, be used to advantage in connection with a belt-type continuous metal-casting machine  30  (FIG. 1) or  30 ′ (FIG.  1 A). Such machines are known in the art of continuous casting and utilize one or more endless flexible belts  22  or  22 ′,  24  or  24 ′ as a wall or walls of a moving mold cavity C. Such a casting belt is moving, endless, thin, flexible, heat-conductive, and liquid-cooled, normally by water. In a machine employing two belts, an upper casting belt  22  or  22 ′ is revolved around an upper carriage U or U′, and a lower casting belt  24  or  24 ′ is revolved around a lower carriage L or L′. The two belts are revolved in unison around oval paths as indicated by arrows  34 , while the molten metal freezes between them in moving mold cavity C formed between the two revolving casting belts to form an emerging cast product P. 
     As known in the continuous casting machine art, a pair of laterally spaced edge dams  25  (only one is seen in FIGS. 1 and 1A) also are revolved (arrow  34 ) and are suitably guided by free-turning rollers  23 . These edge dams define laterally a pair of spaced sides of moving mold cavity C. 
     As an illustrative embodiment, a supply of molten metal M in a melting furnace or holding furnace  28  (FIGS. 1,  1 A) flows into an electromagnetic pump  32  (FIGS. 1,  1 A,  2 ,  3 ,  3 A), optionally provided with self-heating means (not shown). The electromagnetic pump  32  is at a lower elevation relative to level  29  of molten metal for permitting furnace  28  to be drained down to a desired level without need for priming the pump. Internally insulated pipe  36  conveys the metal M upward toward the casting machine  30 . In FIG. 1, the metal M is pumped upward into a tundish or distributor  38  for distributing the flowing metal into the upstream entrance end  42  of the continuous metal-casting machine  30 . 
     Another illustrative embodiment of the invention for feeding molten metal M through an electromagnetic pump  32  into a casting machine  30 ′ is shown in FIG. 1A, where the internally insulated pipe  36  of FIG. 1 is short and curved to form an elbow pipe  36 ′. Upwardly pumped molten metal M is propelled upward in one (or more) free, unconfined parabolic path(s) in the form of one or more unconstrained jet-fountain-streams  27  traveling through a suitably inert ambient atmosphere  31 . The stream (or streams)  27  finally pour into an open pool  40  of molten metal at a position shortly beyond a vertex V of their parabolic path(s). In FIG. 1A the open pool  40  is provided by positioning the upper carriage U′ somewhat downstream relative to lower carriage L′. This jet-fountain-stream method of upwardly pumping and pouring  27  (FIG. 1A) into an open pool has an advantage of avoiding contamination in the event that refractory lining of pipe  36  or  36 ′ may become fragile and crumbly when metals of high melting temperature are poured. Hence, being eliminated is a possible source of contamination of the molten metal M in moving mold cavity C and in product P. Any crumbly particles or flakes of refractory material which might start to be propelled upwardly by the jet-fountain-stream  27  are free to drop out of, and separate from, the unconstrained stream(s) before the stream(s) reach the vertex V. 
     General Design Considerations. 
     My apparatus  32  (FIG. 2) and  32 G (FIG. 4) for impelling or controlling the flow of substantial quantities of molten metal work on the Faraday-Ampère principle in its motor mode, to convert electrical energy into mechanical kinetic energy of the molten metal in a passage  43  of of a pressure conduit  48  (FIG. 2) or  48 G (FIG.  4 ). The apparatus  32  or  32 G is most characteristically a pump, but it is readily reversible electrically and so can be used as a brake or throttle or for reverse-direction pumping. 
     The gap  44  or  44 G should be made as short as possible, both for economy of magnetic material and for minimizing magnetic leakage. For my experimental purposes to date, a gap  44  (FIGS. 2A,  3  and  3 A) and a gap  44 G (FIG. 11) of about 38 mm (about 1.5 inches) has been feasible and successful. These gaps  44  and  44 G contain non-magnetic material, and these gaps are located between a pair of magnetic poles to be described later. An immense electromagnet ordinarily would be needed to bridge such a gap  44  in a two-loop magnetic circuit, shown by dashes at  61  (FIG.  2 ), or to bridge such a gap  44 G in a one-loop magnetic circuit shown by dashes at  61 G (FIG.  4 ). Such a huge electromagnet is avoided by use of permanent “reach-out” magnets  56 , which I also call “neo-magnets” (FIGS. 2,  7 ,  8 ,  9 ,  10 ,  11 ,  17 ) arranged and assembled in various specific powerful configurations as shown. These magnets  56  comprise permanent magnetic material which includes a “rare-earth” chemical element, for example such as neodymium or samarium. A “rare-earth” element is an element in the lanthanide-family series of chemical elements numbered  57  to  71 . The desirable preferred characteristics of such permanent neo-magnet material are described in detail further below. 
     In summary, such “reach-out” permanent magnets, herein also called “neo-magnets”, are notable for the magnetic strength they provide and for their unique energetic ability to drive their magnetic fields B to reach out across relatively wide air gaps, space gaps, or gaps of non-magnetic, i.e. non-ferromagnetic materials, while still providing an intense magnetic field B extending across such a gap. Their reach-out capability is quite superior to the behavior of ordinary magnets in a magnetic circuit having one or more gaps of non-magnetic material. (Paramagnetic materials are treated herein as non-magnetic.) 
     Further description and definitions of my presently preferred neo-magnets are provided later. 
     Construction of a First Embodiment of the Invention. 
     A first embodiment of the invention in the form of an electromagnetic pump  32  is shown in FIGS. 2,  2 A,  3  and  3 A. This pump is capable of exerting a flux density of about 7,000 to 7,500 gauss (about 0.7 to 0.75 tesla) throughout an area of about 26 square centimeters (about 4 square inches) extending across a non-magnetic gap  44  of about 38 mm (about 1.5 inches). A central part of pump  32  is a straight, thin-walled pressurizing conduit  48  comprising a passage  43 . This pressurizing conduit  48  preferably is relatively thin-walled and flattened, for example having a narrow, straight, and substantially constant cross-sectional passage  43  throughout its working area  50 . Passage  43  is shown having a height  67  (FIG. 3A) of about 5.5 mm (about 0.22 of an inch) and width  66  (FIG. 3A) of about 51 mm (about 2 inches). Thus, passage  43  has a cross-sectional area of about 2.8 square centimeters (about 0.44 of a square inch). The pressurizing conduit  48  is here depicted as horizontal, though any orientation of the apparatus  32 ,  50  is workable. Conduit  48  comprises non-magnetic material which resists the heat, corrosion and erosion of the molten metal M moved through pipe  36  (FIG.  1 ). For pumping metals of lower melting points, calcium silicate is suitable; also a non-magnetic metal such as austenitic stainless steel is suitable for forming conduit  48 . 
     The pressurizing conduit  48  has a pumping passage  43  positioned in the path of a unidirectional magnetic field of flux  54  (FIG. 3A) having flux density B. This magnetic field  54  is directed perpendicularly through the narrow (thin) dimension of flattened working area  50 . In this pump  32 , the magnetic field is supplied by two pairs of neo-magnets  56 , each of which in this embodiment is a cube for example measuring about 51 mm (about 2 inches) along each edge. A first pair of magnets  56  with the pole piece  58  are shown above gap  44  (FIGS. 2A,  3  and  3 A). This gap  44  is shown measured in a direction parallel with the axis B of the unidirectional magnetic flux  54  (FIG.  3 A). A second pair of neo-magnets  56  with their pole piece  58  is positioned below gap  44 . These tapered pole pieces  58  are formed of a ferrous, soft-magnetic (ferromagnetic) material, for example machinery steel described in more detail later. Bach magnet pair is retained together with its pole piece  58  by a four-sided shell or jacket  59  formed of suitable non-magnetic material, for example, aluminum secured to a frame  60  by screws  52  as in FIG.  2 A. These two shells  59  are configured for snugly embracing respectively the first and second pair of neo-magnets  56  together with their respective tapered pole pieces  58 . The angular slope of each side of pole piece  58  is kept not more than an angle of about 30° relative to the longitudinal axis of this pole piece, because a greater angle of convergence causes an undesirable increase in leakage flux. A convergence of about 30° on only two sides of pole piece  58  is shown in FIG.  2 . 
     A ferrous soft-magnetic (ferromagnetic) generally rectangular frame  60  encircles the neo-magnet assemblies and establishes a magnetic circuit  61  having two loops both extending across the gap  44 . Machinery steel, for example comprising about 0.2 percent of carbon by weight is magnetically “soft”, i.e., it is ferromagnetic and is suitable for making pole pieces  58  and frame  60 . Machinery steel, for example, also is suitable for making a bridge piece  62 , which is included in one loop of the two-loop magnetic circuit  61 . Bridge piece  62  is removably fastened by bolts  64  to allow disassembly of the whole pump apparatus  32  for enabling removal of pressurizing conduit  48 ,  50 . 
     The upper and lower pole pieces  58  have respective upper and lower magnetic pole faces  87  (FIG.  2 A). These pole faces are positioned in spaced parallel relationship and define the non-magnetic gap  44 . These upper and lower parallel planar pole faces are square, measuring about 51 mm (about 2 inches) along each side, thereby each having a pole face area of about 27 square centimeters (about 4 square inches). These pole faces fit flush and snug against upper and lower parallel planar surfaces of flattened working area  50  (FIGS. 3 and 3A) of conduit  48 . The magnetic polarity of the upper and lower pole faces  87  is respectively North (N) and South (S). 
     As explained above, vertical spacing between these parallel, planar pole faces establishes the non-magnetic gap  44  (FIGS. 2A,  3  and  3 A) in the two-loop magnetic circuit  61 . This gap of about 38 mm (about 1.5 inches) is substantially the same as the vertical distance between upper and lower parallel planar surfaces of working area  50 . 
     As shown in FIG. 2, the ferromagnetic frame  60  includes an elongated upright member  60   a  removably fastened by bolts  63  to upper and lower transverse members  60   b  and  60   c , respectively. These transverse members are removably fastened by other bolts  63  to upper and lower upright members  60 ′ arid  60 ″, respectively, with bridge piece  62  bolted across a space between them. 
     In FIG. 3A the flux lines of a vertical magnetic field B are indicated in section by multiple crosses  54 . These crosses indicate the pattern (distribution) of magnetic flux  54 . 
     The crosses  55  indicate weak margins of flux pattern  54 . An electrical direct current I is driven transversely through the molten metal at a low potential. In FIG. 3 this current I flows in a direction indicated by large polarity symbols plus (+) and minus (−). This direct current I travels through molten metal in the electrically non-conductive flattened part  50  of pressurizing conduit  48  and across its channel  43  within the channel&#39;s narrow vertical dimension  67  of about 5.5 mm (about 0.22 of an inch) and across its broad dimension  66  of about 51 mm (about 2 inches). The current I is conveyed to the molten metal by means of two elongated electrodes  68  (FIG. 3A) each having an electrical connection post  51  (FIGS.  3  and  3 A). 
     The magnitude (amperage) of this direct current is suitably controlled for controlling the pumping flow rate. Increasing current I increases impelled flow rate, and vice versa. Reversing current I reverses the direction of pumping and hence reverses the impelled flow of molten metal. 
     The current I traverses the molten metal M inside the pressurizing conduit  48  at right angles to both the direction of flow of metal M and the direction of magnetic field B. The molten-metal-contacting portions of electrodes  68  are inserted into elongated apertures  57  in the opposite narrow sides of conduit  48 . Outer portions of electrodes  68  are captured in elongated sockets  69  in two removable H-shaped electrode holders  47  which are mounted onto opposite narrow side walls of conduit  48 . These holders  47  are non-conductive and non-magnetic and are secured to conduit  48  by screws  49  engaging in threaded holes  49 ′ in the holders  47  and screw clearance holes  49 ″ in conduit  48 . 
     Electrodes  68  preferably are made of a carbonaceous material, for example such as graphite. Electrodes  68  of metal which is chemically different from the molten metal being pumped will likely be quickly dissolved by electrolytic action. Electrodes of the same metal as the pumped metal are not as subject to electrolytic dissolution. Metal electrodes  68  having internal cooling passages can be cooled by circulated coolant such as water flowing through tubing  46  (FIG. 2) shown in dashed outline and through nipples  53  communicating with such internal passages. This cooling not only prevents melting of metal electrodes  68 , but also can cause a solidified protective cap from the molten metal to freeze upon the exposed face of each electrode. If the pressurizing conduit  48  is formed of suitable electrically-conductive non-magnetic metal, for example austenitic stainless steel, then the same current source which supplies the d.c. cross-current I may be used to preheat the pressurizing conduit by electrical resistance heating action, thereby preventing freeze-ups at the start. The employment of such metal for the pressurizing conduit  48  allows metallic electrodes  68  to be welded or brazed to the outside of said conduit and not penetrate its wall at all. 
     In operation, there is a steady pumping pressure along the channel of the pressurizing conduit  48 ,  50 . By sudden reversal of the current I, the direction of pressure is reversed, instantly. This reversal is useful for braking or suddenly stopping a flow of metal, for example in repetitive starting and stopping of molten metal flow for casting a sequence of identical discrete objects in a succession of identical movable molds, which are sequentially suitably positioned and then held stationary for receiving their respective identical infillings of molten metal. 
     Another embodiment of the invention is shown, for example as an augmented electromagnetic pump: This augmented pump  32 G (FIG. 4) differs from pump  32  in that it employs an x-y-z assembly of permanent neo-magnets  56  in a quintuply concentrative magnetic configuration  80 N as shown in FIGS. 7 through 11. Another similar but inverted quintuply concentrative assembly  80 S is described later. These concentrative assemblies  80 N and  80 S intensify magnetic flux density B′ to about 100 percent above that in pump  32 . They thereby exert an augmented flux density B′ of about 14,000 to about 15,000 gauss (about 1.4 to about 1.5 teslas) across the non-magnetic gap  44 G (FIG. 11) in which is positioned pressurizing conduit  48 G having a pumping passage  43 G. 
     The central portion of pressurizing conduit  48 G (FIGS. 4,  5 ,  6 ) comprises a flattened working area  50 G. This flattened working area  50 G is relatively longer than flattened area  50  (FIGS. 3 and 3A) to permit the ten cooperating neo-magnets  56  (five each in their respective concentrative assemblies  80 N and  80 S) with their respective pole pieces  86  to be positioned suitably close to the conduit  48 G in relation to flattened area  50 G. This conduit has a narrow passage  43  which preferably is relatively thin-walled and flattened, for example having a narrow, straight, substantially constant cross-sectional shape of height  67 G (FIG. 4) of about 8 mm (about 0.315 of an inch) and width  66  (FIG. 4) of about 51 mm (about 2 inches). Thus, passage  43  has a cross-sectional area of about 4 square centimeters (about 0.63 of a square inch). Conduit  48 G is here depicted as horizontal, though any orientation of the apparatus  32 G,  48 G is workable. The augmented magnetic flux  54 G of field B′ is directed perpendicularly through the thin dimension of flattened working area  50 G. In FIG. 5 the pattern (distribution) of magnetic flux lines  54 G of field B′ is indicated in cross section by multiple small crosses. Crosses  55  indicate weak margins of the magnetic flux  54 G. 
     Previously it was explained that apparatus embodying the invention is workable with passage  43  for molten metal oriented in any convenient direction relative to horizontal. For convenience of illustration, a horizontal orientation of molten metal passage  43  is shown in the drawings. 
     FIGS. 7 through 10 illustrate the assembly  80 N of five cubical permanent neo-magnets  56  arranged in a concentrative configuration together with a centrally-located ferromagnetic pole piece  86 . It is noted that FIG. 7 shows mutually orthogonal axes x-x, y-y and z-z, with the axis z-z being oriented vertically for illustrative clarity. The central pole piece  86  is almost cubical, except it is elongated somewhat in the z-z direction for providing a North-polarity magnetic pole  87  which projects downward from the assembly  80 N. Thus, the North-polarity square face  87  of this pole piece  86  seats down flush and snug against the working area  50 G of the pressurizing conduit  48 G. Technically speaking, pole piece  86  is a solid rectangular parallelepiped having square upper and lower end surfaces and four rectangular side surfaces. An upper cube neo-magnet  56  whose magnetic field is aligned with the axis z-z is seated flush on the square upper end surface of pole piece  86 . Its square North-pole lower surface matches in size and shape with the contiguous square upper surface of pole piece  86 . 
     Two cubic neo-magnets  56  magnetically aligned with axis x-x have their North-pole surfaces seated flush against opposite sides of pole piece  86 . Their respective North-pole surfaces match the width of side surfaces of pole piece  86 , and their top surfaces align with the top surface of the pole piece. Two other cubic neo-magnets  56  are magnetically aligned with axis y-y. Their North-pole surfaces seat flush against the two other opposite sides of pole piece  86 . Their respective North-pole surfaces match the width of side surfaces of pole piece  86 , and their top surfaces align with the top surface of the pole piece. 
     The North-polar half of the magnetomotive force in this construction is supplied by the assembled quintupally concentrative array  80 N of five neo-magnets  56  (FIGS. 7 to  11 , also  4 ). This assembly  80 N is positioned within a ferromagnetic cantilevered C-frame  60 G (FIG.  4 ). This frame  60 G is made of magnetically soft, i.e., ferromagnetic, machinery steel (about 0.2 percent by weight carbon content), and this frame establishes the magnetic circuit  61 G. The left side of C-frame  60 G in FIG. 4 remains open to allow easy removal of pressurizing conduit  48 G together with its associated components. 
     This C-frame  60 G includes an upright elongated member  71  having an adjusting shoulder block  82  secured to its upper end. A clamp adjusting screw  83  having a lock nut  78  is threaded through this shoulder block for holding removable top clamp member  82  down firmly against a top plate of an upper ferromagnetic pot  88  to be described later. An elongated foot member  81  secured to a lower end of upright member  71  extends beneath a lower plate of a lower ferromagnetic pot  88  described later. 
     FIG. 7 shows five neo-magnets  56  assembled with their pole piece  86  as described above. Inert filler blocks  84  (FIGS. 9 and 10) are omitted from FIGS. 7 and 8 for clarity of illustration. These inert filler blocks are cubes of the same size as neo-magnets  56  and, for example, are constructed of aluminum (Al). For distinct illustration, the outlines of twelve filler blocks  84  in FIGS. 9 and 10 are shown by dotted lines. 
     From FIG. 9, it is seen that this concentrative magnetic assembly  80 N substantially comprises two layers. The upper layer contains one neo-magnet cube  56  encircled by eight inert cubes  84 . In FIG. 10, it is seen that the lower layer contains the central pole piece  86  encircled by four neo-magnet cubes  56  and four inert cubes  84 . The neo-magnets are contiguous with the four-side surfaces of pole piece  86  as described above. The four cubes are adjacent to the four vertical edges of the pole piece. Thus, eighteen components comprise assembly  80 N. 
     The South-polar half of the magnetomotive force in this construction is supplied by a concentrative magnetic assembly  80 S, shown in FIG.  11 . Assembly  80 S is substantially the same as North-polar assembly  80 N, except assembly  80 S is inverted from what is seen in FIG. 11, so its pole piece  86  is in the upper layer of assembly  80 S projecting above the upper layer for its South polarity face  87  to seat up flush and snug against the lower working surface  50 G (FIG. 11) of the conduit  48 G. Also, the five neo-magnets in assembly  80 S have their South-pole faces contiguous with the South-polarity pole piece  86 . 
     Arrays  80 N and  80 S are confined by respective upper and lower magnetically soft ferrous pots or enclosures or retainers  88  (FIGS. 4,  11 ), for example made of plates of machinery steel. Pots  88  continue the magnetic circuit  61 G from frame  60 G to outside faces of the five neo-magnets  56  in the concentrative assemblies. Pots  88  contact pole faces of neo-magnets  56  opposite to their pole faces in contact with their pole piece  86 . In addition to providing portions of magnetic circuit  61 G, the pots  88  physically retain the contained neo-magnets against their strong mutual magnetic repulsion. Pots  88  need not be everywhere closed provided that the magnetic flux is adequately channeled. 
     Elongated electrodes  68  captured in elongated sockets  69  in holders  47  (FIG. 6) and their cooling connections  53  with coolant tubing  46  (FIG. 4) are similar to those previously described for the pump  32 . An electrical direct current I is driven by those opposed electrodes  68  (only one is seen in FIG. 6) through the molten metal in the direction indicated by plus and minus symbols. Current I travels across the broad dimension  66  (FIGS. 4 and 6) of working area  50 G of non-magnetic, pressurizing conduit  48 G within its narrow vertical dimension  67 G of about 8 mm (about 0.315 of an inch) (FIGS. 4 and 11) 
     A non-magnetic, heat-conductive cooling pancake cell  74  (FIGS. 11,  12  and  13 ) for example made of aluminum, is interposed between the magnetic array  80 N and the pressurizing conduit  48 G. Another such cooling cell  74  is similarly interposed with respect to magnetic array  80 S. Each laminated cooling cell  74  is supplied with liquid coolant flowing through tubing  72  and nipples  73  (FIG. 12) to protect neo-magnets  56  from the heat of nearby molten metal in passage  43 G. Coolant such as water flows through passages  76  cut into each plate  77  to keep the rare-earth neo-magnets  56  cool enough to preserve their magnetism. There is a non-magnetic, heat-conductive thin plate  75  for covering the passages  76 , for example made of aluminum. Each cover plate  75  is cemented and sealed to its adjacent plate  77 . 
     Neo-magnetic Material. 
     My presently most preferred magnetic material for neo-magnets  56  is based on a tri-element (ternary) compound of iron (Fe), neodymium (Nd), and boron (B), which is known generically as neodymium-iron-boron, Nd—Fe—B, usually written NdFeB. Permanent magnets containing NdFeB are commercially available. These permanent reach-out neo-magnets containing NdFeB exhibit a maximum energy product in a range of about 25 to about 35 MGOe (Mega-Gauss-Oersteds). 
     I envision that in the future other reach-out permanent magnetic materials, for example ternary compounds such as iron-samarium-nitride and other as yet unknown ternary-compound permanent magnetic materials having a maximum energy product MGOe in said range and above said range and also having B-H characteristics similar to those as shown in FIG.  14  and being suitable for use in embodiments of this invention, may become commercially available. Also, as yet unknown four-element (quaternary) permanent magnetic materials may become commercially available having a maximum energy product MGOe in or above said range with B-H characteristics suitable for use in embodiments of this invention. 
     In FIG. 14, the height of the extreme right point  102  of the loop  100  (in quadrant i) represents a maximum saturation B s  of a suitable neo-magnetic material for use in embodiments of my invention. This maximum saturation B s  is established when a neo-magnet  56  is initially magnetized by the manufacturer. When the neo-magnet  56  is removed from a manufacturer&#39;s electromagnet, a previously imposed coercive magnetizing force H in oersteds (measured along a horizontal axis) ipso facto becomes zero. Under this condition of zero magnetizing force, the residual (i.e. self-maintained) magnetic flux density B r  in gauss is represented by a point  104  along a vertical B-axis, where the neo-magent&#39;s hysteresis loop  100  crosses the B-axis. This B r  value is known as the residual induction of the neo-magnet. For purposes of my invention, the residual induction B r  preferably is equal to or greater than (no less than) a residual flux density in a range of about 8,000 to about 10,000 gauss (about 0.8 to about 1.0 tesla). This high value and even higher values of residual induction B r  are attainable with neo-magnetic material preferred to be used for constructing embodiments of the invention. It is more preferred to use neo-magnets having a residual induction B r  in a range of about 10,000 to about 12,000 gauss (about 1.0 to 1.2 tesla) and most preferred to have B r  above about 12,000 gauss (about 1.2 tesla). 
     It is noted that about the same high residual induction also is attainable with alnico 5, a permanent-magnetic material which has long been cheaply available and whose approximate hysteresis loop (B-H curve) is shown at  120  in FIG.  14 . This slim alnico 5 loop crosses the B axis at a residual induction B of about 12,800 gauss (about 1.28 teslas), as measured from an alnico 5 hysteresis loop shown in FIGS. 6-3 of the above-listed reference book by Moskowitz. This residual induction of alnico 5 magnet material is not far different from that of neo-magnetic materials; however, alnico 5 magnets are not practical nor suitable for use in embodiments of this invention, as will be explained later. 
     The suitability of neo-magnets, for example NdFeB neo-magnets, arises not only from their high residual induction B r  (FIG.  14 ), but more importantly from their low differential demagnetizing permeability as shown by the low slope ΔB/ΔH of the portion  112  of their demagnetizing curve  106 . This portion  112  of demagnetization curve  106  is located within circle  110  in the second quadrant “ii” of the B-H plot. This demagnetization curve portion  112  extends from a first point  104  where demagnetization curve  106  crosses the +B axis at its value on the +B axis scale, to a second point  108  where this demagnetization curve  106 , crosses the −H axis (minus-H axis) at its value on the −H axis scale. The low slope ΔB/ΔH is herein defined as being the slope of curve portion  112  as measured midway along this curve between its two points  104  and  108 , namely, its “midpoint differential demagnetizing permeability,” which is shown in FIG. 14 as being about 1.15. 
     This unique reach-out ability of a high-energy permanent neo-magnet  56  to drive an intense magnetic field B through a non-magnetic gap  44  (FIGS. 3 and 3A) or  44 G (FIG. 11) in a magnetic circuit, (for example as shown at  61  (FIG. 2) and as shown at  61 G (FIG. 4) may be understood by considering or thinking that such a magnet functions internally—incidentally but inherently—as its own non-magnetic gap, i.e. as a gap which does not contain ferromagnetic material. In other words, such a magnet functions as though it comprises an internal virtual gap corresponding almost to the cumulated length of the neo-magnet  56  itself as measured in the direction of the magnetic flux. Hence, the addition of a somewhat comparable exterior, real, physical, non-magnetic gap, for example such as gap  44  or  44 G, does not cause much reduction of the flux  54  shown in cross section by multiple small crosses in FIGS. 3A and 5 in the magnetic circuit  61  (FIG. 2) or  61 G (FIG.  4 ), i.e. does not cause much reduction in intensity of the magnetic field B being driven across such a relatively long gap in such a magnetic circuit. 
     For the purposes of my invention, the slope at a midpoint  112  along the demagnetization curve  106  is preferably equal to or less than about 4 and more preferably is less than about 1.2, whereas the magnetic permeability of air or vacuum is unity by definition. In FIG. 14, the slope at point  112  is shown as being about 1.1, which in my experience is provided by commercially available NdFeB neo-magnets. The smallness of this slope reflects a magnetic “hardness”, an abiding, intrinsic residual magnetism. This preferable slope relatively close to unity is called differential demagnetizing permeability measured in Δgauss per Δoersted. 
     A practical suitable parameter of a preferred neo-magnet  56  parameter which parameter tends to track the desired reach-out characteristic is called the maximum energy product; it is the product of residual induction B r  at midpoint  112  multiplied by an amount of demagnetizing oersteds required to bring the residual induction B r  of a neo-magnet  56  down from the point  104  on the B axis to the midpoint  112 . This product is expressed as mega-gauss-oersteds (MGOe), a common commercial designation. As scaled in FIG. 14, a neo-magnet so depicted would have at least about 25 mega-gauss-oersteds of energy product. It is preferred to use neo-magnets having the highest values of MGOe which is reasonably economically obtainable, for example at least about 30 MGOe to about 35 MGOe and above. By contrast, alnico 5 is not suitable. 
     A demagnetization curve  122  for alnico 5, shown within a circle  110  (FIG.  14 ), drops almost vertically at a slope of about 30 ΔB/ΔH, and this demagnetization curve  122  crosses the H axis at a point  126  having a value less than about 1,000 oersteds. A suitable neo-magnet, by contrast, has a demagnetization curve  106  that usually is a relatively straight line  106  of much less slope, extending between points  104  and  108 , whose slope ΔB/ΔH is relatively close to unity. 
     In FIG. 16, the two curves contrast the flux densities (y-axis) obtained with alnico 5 and reach-out neo-magnets. The independent variable (x-axis) is the thickness or length of the non-magnetic gap in their respective magnetic circuits. The effect of a given gap is different for different sizes and configurations of magnetic assemblies; here the gap is shown plotted to correspond to the apparatus herein described. 
     Available commercial magnets  56  which can be used in embodiments of the invention comprise a mixture of cobalt and samarium (Co 5 Sm) having a maximum energy product of about 20 MGOe and a residual induction B of about 9,000 gauss (0.9 tesla) and an almost-unity midpoint differential demagnetizing permeability of about 1.08. Also, available commercial magnets which can be used contain cobalt-samarium material (Co 17 Sm 2 ) and have a maximum energy product of about 22 to about 28 MGOe and a residual induction B r  in a range of about 9,000 gauss (about 0.9 tesla) to about 11,000 gauss (about 1.1 tesla) and an almost-unity midpoint differential demagnetizing permeability in a range of about 1.15 down to about 1.0. 
     A limitation on the magnetic flux density attainable in the nonmagnetic gap  44 G is the ability of the pole piece  86  to carry it. For iron as nearly pure as machinery steel, magnetic saturation is said to occur at about 2.1 tesla. If about a third of the iron is replaced by an equal alloyed part of cobalt, this limit is said to rise to about 2.4 tesla (see Douglas, pp. 761-763, listed above). However, in my experience, these limits are not reached in the nonmagnetic gap  44 G more closely than approximately 70 percent because of substantial leakage flux occurring around the neo-magnets themselves. This magnetic leakage is due to the magnetic reluctance of the nonmagnetic gap  44 G. 
     Input to the parallelepiped pole piece can be provided also, for instance, from 1, 2, 3, 4, 5, 6, 7 or more sides, with each side of such pole piece being snugly adjacent to the pole face of each neo-magnet  56  concerned. In general, the more sides of a pole piece receiving magnetic input, the better. For the case of a pole piece  91  of three symmetrical sides plus two ends, the pole piece would be of triangular cross-section (FIG.  13 A). A triangular end-cap neo-magnet  56 ′ can be added, and the other end of pole piece  91  is its North pole face  87 . For the case of six sides plus two ends, the pole piece  92  would be of hexagonal cross-section (FIG.  13 B). A hexagonal end-cap neo-magnet  56 ″ can be added. The other end  87  of pole piece  92  is its North polarity pole face. 
     As a limiting case, a circular cylindrical pole piece  93  (shown half in section) is surrounded by an annular magnetic ring  94  magnetized in the direction through its radial thickness throughout, as is shown in FIG. 13C. A circular cylindrical cap  97 , magnetized longitudinally in a direction along its cylindrical axis completes this magnetic assembly. The other axial end  87  of pole piece  93  is its North polarity pole face. None of the non-square cross-sectional shapes shown in FIGS. 13A, B and C drives a square magnetic field through the passage  43  or  43 G; hence, some fringes of the imposed magnetic field are outside of the width dimension  66  of passage  43  or  43 G, and some fringes are upstream and downstream of the electrodes. However, this non-square magnetic field does not result in eddy-leaks of molten metal at the edges of the pumping action in passage  43  or  43 G because the current I flowing between straight, parallel opposed electrodes covers very nearly a square or rectangular area extending across passage  43  or  43 G, with the result of uniform pumping force across the flow channel. 
     FIG. 17 shows an assembly of two elongated pole pieces  95  each with four long sides. Three sides of each pole piece are supplied with magnetic flux by three long neo-magnets  96 , and the fourth side is an elongated pole face  87 . Such a long pole face  87  can be oriented transversely relative to metal flow for use, for example, with an extra-wide-dimension  66  pumping passage. Small neo-magnets  56 , shown in exploded relationship, can be applied to the ends of each elongated pole piece  95  to make a total of 5 neo-magnets for each pole piece if desired, unless magnetic flux leakage at the two ends of each long pole piece may be ignored. 
     In general, for obtaining suitable economic and practical results, an electromagnetic pump design embodying the present invention will be arranged to minimize magnetic leakage and stray magnetic flux so that the great magnetic energy and the reach-out capability of neo-magnets will provide an intense magnetic field B extending across the non-magnetic gap  44 ,  44 G and  44 J (FIG. 19) and passing through the pressurizing conduit positioned within this gap. Thus, for example, this non-magnetic gap  44 ,  44 G and  44 J is minimized insofar as is reasonably practicable. 
     Adjacent neo-magnetic elements with the same orientation of poles may be assembled together and treated as effectively one magnet. For example, eight cubic neo-magnets measuring one inch along each edge can be assembled into a cubic configuration measuring two inches along each edge. In general, the neo-magnets will repel each other when so assembled and hence need to be constrained against their mutual repulsion. 
     Flow sensing. 
     Any one of various kinds of metal-level-sensing apparatus at the casting machine as known in the art may send a signal for indicating level or limits of molten metal in the casting apparatus. Advantageously, such a signal can be fed to a control for a DC power supply which is providing current I for controlling magnitude (amperage) of this current for controlling pumping rate for conforming to the level or limits of the casting machine or mold, without either overflowing or allowing voids or cold-shuts to occur in the cast metal. One suitable proximity coil device for signaling molten-metal level in a continuous casting machine is described in U.S. Pat. No. 4,138,888 of Sten V. Linder. 
     One or more pairs of small additional embedded passive sensing electrodes  132  and  134  (FIG. 3A) with respective connectors  136  and  138  (FIGS. 3A and 5) protrude through the wall of a fluid pressurizing conduit to contact the molten metal flow M (FIGS. 5,  3 A,  3 ,  2 ,  4 ). 
     Where magnetic flux penetrates a conduit, moving liquid metal in the conduit generates an e.m.f. at right angles both to the flux and the flow, according to the Faraday principle in its generating mode whereby mechanical energy is converted into electrical energy. The signal is proportional to the rate of flow passing between two electrodes  132  and again between the other two electrodes  134 . These passive sensing electrodes  132  and  134  (FIGS. 5 and 3A) respectively define paths across the relatively weaker fringes  55  or  55 G of the magnetic field  54  or  54 G which is driving the molten metal. Two pairs  132  and  134  of electrode sensors are shown positioned upstream and downstream of the working area  50  and  50 G. The electrical outputs from these two pairs of electrodes are combined and averaged. The average electrical output from these sensors is fed to a meter (not shown) suitable for enabling manual control of DC current I or is fed into a DC current control (not shown) to stably and precisely control the pump  32  or  32 G or else to operate the apparatus  32  or  32 G as a brake, or throttle. Hence, the advantageous ability of embodiments of the invention to match molten-metal input to the speed of a continuous metal-casting machine is realized. 
     Either pair of electrodes  132  or  134  would be sufficient for the purpose of control, except notably that the necessarily fluctuating DC driving current between nearby electrodes  68  and the associated changing magnetic field of the fluctuating current creates undesired e.m.f&#39;s between the pairs of sensing electrodes  132  or  134 . However, a symmetrical upstream-downstream location of sensing electrodes with respect to the DC-current driving electrodes  68  causes the undesired e.m.f&#39;s to cancel each other and so not disturb the generated and combined control e.m.f. to be fed into a meter or a DC current control. 
     Instead of using the fringe field  55  or  55 G for generating an e.m.f. according to the Faraday principle in its generating mode, separate magnets may be used, suitably positioned upstream or downstream from the fringe field for providing a magnetic field passing through the molten metal flow in a direction parallel with field B. In this event, only one pair of sensing electrodes like those identified above is sufficient. 
     FIGS. 18 and 19 show an electromagnetic pump  32 J embodying the invention. First and second powerful cubical magnetic assemblies  180 N and  180 S each contain eight cubic neo-magnets  56  measuring about 51 mm (about 2 inches) along each edge. Thus, each powerful cubical magnetic assembly  180 N and  180 S measures about 102 mm (about 4 inches) along each edge and has an overall pole face  87  with an area of about 104 square centimeters (about 16 square inches). These pole faces  87  seat flush against a pancake cooling layer  74 , and these pancake coolers seat flush against opposite faces  50 J of the working area of conduit  48 J. 
     A large ferromagnetic frame  160  encircles the two other magnetic assemblies. This frame includes upper and lower transverse members  160   b  and  160   c  and two upright members  160   a  and  160   d . These frame members are suitably secured together by removable machine screws (not shown) for example similar to the arrangement of machine screws  63  in FIG. 2 so that the frame  160  can readily be disassembled. 
     It is noted that the upright members  160   a  and  160   d  are spaced relatively far from the two magnetic assemblies so as to minimize leakage of magnetic flux. Also, the non-magnetic gap  44 J between the opposed pole faces  87  as shown is only about 38 mm (about 1.5 inches). 
     In order to hold the two magnetic assemblies  180 N and  180 S together against the mutual repulsion between their neo-magnets  56 , they are contained within respective non-magnetic retainer casings, shown in dashed outline, for example made of aluminum. 
     The passage  43  has a height  67  of about 8 mm and a width  66  of about 102 mm (about 4 inches). 
     The pair of opposed electrodes (not shown) for feeding DC current I transversely through molten metal flow M are suitably mounted as explained above, and they each have a length of about 102 mm (about 4 inches) 
     A TEST-RIG PROTOTYPE 
     A convenient test-rig prototype employs a bismuth alloy similar to what is traditionally known as Wood&#39;s metal. This metal advantageously melts at a relatively low temperature of 70° C. (159° F.). It has a specific gravity of 10.5 g/cm 3  (0.38 lbs/in 3 ). 
     A repeatable experiment was performed with test-rig  150 , shown in elevation in FIG.  15 . Pump  32  pumped metal from melting container  152  through pipes  154  and through straight, thin-wall pressurizing conduit  48  having a passage  43  of constant cross-sectional area for impelling the molten metal toward a head-measuring column  156 . When a valve  158  was opened, the metal freely circulated from container  152  through pipes  154  and  160  and back into the container. 
     The temperature of the molten Wood&#39;s metal as pumped by pump  32  was about 93° C. (200° F.). The pressurizing conduit  48  was machined from a block of calcium silicate and had a shape like conduit  48  in FIG.  3 . The passage  43  in the conduit  48  had a height of about 5.6 mm (about 0.22 inches) and a width of about 51 mm (about 2 inches), thus having a cross-sectional area of about 2.8 square centimeters (about 0.44 sq. inch). 
     A unidirectional magnetic flux density of about 7000 gauss (0.7 tesla) was applied through a gap of about 38 mm (about 1.5 inches) over an area of about 26 square centimeters (about 4 sq. inches) in the direction shown by the arrow B in FIGS. 15 and 2 through the two tapered pole pieces  58 . This magnetic field was provided by four NdFeB commercially available high-energy neo-magnets placed as shown by mostly dashed lines in FlGS.  2  and  2 A—two above with one pole piece  58  and two below with the other pole piece. Each of the four reach-out neo-magnets  56  was a cube measuring about 51 mm (about 2 inches) on each edge. With molten metal in the pump, a controllable electrical direct current (DC) of 0 to 500 amperes was applied between spaced parallel copper electrodes  68  of face area of about 2.4 square centimeters each, the current being in the direction shown by arrow I in FIGS. 2,  2 A,  3  and  3 A. This 500-ampere DC current was supplied by a welding machine capable of exerting 10 volts, though less than 4 volts were applied between the electrodes. During the tests described below, the voltage drop between the electrodes  68  and across the molten metal at 500 amperes measured about 0.5 volt. 
     Before the measurements of flow and head were made, the molten metal was allowed to circulate per arrows  161  and  159  for a few minutes to warm up the externally insulated pipes  154  and  160  as well as the externally insulated pressurizing conduit  48 . The height of molten metal corresponding to zero pressure head as measured by an instrument measuring gauge pressure, i.e. pressure relative to atmospheric pressure, was the height of the free level  164  “PrHd o ” of the liquid metal  165  in the melting container  152 . Steady atmospheric pressure on surface  164  of the liquid metal was ensured by loose-fitting cover  166 . With the pump turned off, this level  164  was also the level of the liquid metal surface in open-top pressure-head-measuring column  156  (the insulation is not shown, for clarity of illustration). With the pump turned on and the valve  158  wide open, the liquid-metal level in column  156  did not increase much; the slight increase (which for simplicity is not distinguished further herein) was due mainly to the back pressure of friction and turbulence in pipe  160 . Thus, the circulating flow rate (arrows  161  and  159 ) was measured as about 0.3 liters per second or about 11 metric tonnes per hour. 
     Then the valve  158  was closed to measure the available pressure head Ht in the absence of flow, i.e. at shutoff. To measure this highest pressure head Ht exertable by the pump, a block of aluminum  168  was floated on the surface of the Wood&#39;s metal in the column  156 . A fine wire  172  attached to it went around a pulley  174  mounted at the top of the open-top column  156 , the wire going down to be fastened to a counter-weight  170 . From the vertical position of the counter-weight, simple arithmetic disclosed the height of the Wood&#39;s metal in the column. 
     The vertical liquid-metal columnar surface lift obtained with the valve  158  closed, i.e. in the absence of flow, was 350 mm above its height at zero pressure head PrHt o , a vertical distance “Ht,” which is to say a pressure head “PrHd max ” of 370 grams/cm 2  or 0.36 bar relative to the molten-metal level  164  (PrHd o ) at the liquid surface  164  of the melting container  152 . This pressure head is calculated by multiplying the lift height Ht of 35.0 centimeters times the specific gravity 10.5 g/cm 3  of the molten metal  165 . 
     The flow rate of the molten metal was sensed electromagnetically as described above, and the signal so generated controlled the pumping rate for keeping this rate substantially constant at about 0.3 liters per second as described above. 
     This experiment and its materials and parameters are described for expository purposes only and not to limit the scope of the invention, which may be embodied in a variety of apparatus with a variety of methods, materials and parameters. 
     Electromagnetic pumps embodying the invention can be used to raise molten copper to the height of a conventional tilting furnace, namely, as much as 3 meters of lift and more, that is, to a height of lift adequate to feed a continuous casting machine for example as shown in FIGS. 1 and 1A from an existing low-lying stationary furnace. In this way, the tilting furnace is no longer needed for holding and metering the pouring of molten metal into such a machine. 
     Although specific presently preferred embodiments of the invention have been disclosed herein in detail, it is understood that many shapes and patterns of assemblies of neo-magnetic elements besides those described herein can be used to produce useful results. More generally, it is to be understood that the examples of the embodiments of the invention herein have been described for purposes of illustration. These disclosures are not intended to be construed as limiting the scope of the invention, since the described methods and apparatus may be changed in details by those skilled in the art of continuous casting and in the conveyance of molten metals in order to adapt these methods and apparatus to be useful relevant to particular continuous casting installations or for sequential pouring into a series of substantially identical molds, without departing from the scope of the following claims.