ELECTROMAGNET FOR MOVING TUBULAR MEMBERS

Abstract

A novel electromagnet for moving tubular members is described, in which the flux lines extend only downwards in the direction of the load whereas the laterally dispersed magnetic field is substantially absent. The polar yoke of such an electromagnet has two North polarity cores on which two solenoids are wound, protected on the bottom by annular baffles made from non-magnetic material, and side panels made from ferromagnetic material extend along both sides and pass next to the two cores magnetically connecting the three South polarity poles, the side panels being magnetically insulated from the two cores. The thickness of the side panels is sized such that they are suitable to short-circuit the whole lateral flux preventing the dispersion thereof and conveying it completely towards the polar shoes of the three poles and into the material to be magnetized thus actively contributing to the lifting of the latter.

Claims

1. A system for transporting loads using a magnetic force comprising: at least one electromagnet, wherein the at least one electromagnet includes: at least two solenoids each wound on a respective core of a polar yoke, side panels, annular bottom baffles for protection of the at least two solenoids, first polar shoes at the cores of the polar yoke, second polar shoes at poles of the polar yoke, a bottom active surface; wherein: the polar yoke has a shape corresponding to at least two aligned E-shaped yokes with at least two cores and three poles, the side panels are made from ferromagnetic material and magnetically connect the poles while being magnetically insulated from the cores, the side panels have a thickness sized such that the side panels are suitable to short-circuit a whole lateral flux of a magnetic field generated by the electromagnet and to convey the whole lateral flux towards the second polar shoes, the annular bottom baffles are made from non-magnetic material and reside on the two solenoids as part of a whole bottom surface of the electromagnet, and the bottom active surface is the whole bottom surface, less the annular bottom baffles, during operation, the at least two cores have a first polarity, and the side panels and the at least three poles have a second polarity opposite to the first polarity, and the electromagnet generates flux lines extending only downwards in the direction of a load to be moved; and at least one load, wherein the at least one load is at least one tubular member containing ferromagnetic material, held to the bottom active surface of the at least one electromagnet by a magnetic force.

2. The system of transporting loads according to claim 1, wherein the at least one load is a bundle of tubular members.

3. The system of transporting loads according to claim 2, wherein the bundle of tubular members is held together by at least one strap, and the flux lines that exit the cores and close into the side panels generate polarities on surfaces of the tubular members, the polarities of adjacent tubular members being of opposite signs.

4. The system of transporting loads according to claim 1, further comprising a load transfer location in the proximity of other ferromagnetic members such as other loads or stalls or metal side planks, wherein the electromagnet and the at least one load are being moved to a specific position in the load transfer location during a load transfer phase.

5. The system of transporting loads according to claim 4, further comprising means for programming transport coordinates such that the system can be operated in an automatic manner without the presence of an operator.

6. The system of transporting loads according to claim 1, wherein the electromagnet further comprises recesses shaped to receive the at least two solenoids, the solenoids being buried in insulating resins and manufactured from copper wire strips.

7. The system of transporting loads according to claim 1, wherein the bottom baffles are made of wear-resistant manganese steel.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0019] These and other advantages and characteristics of the electromagnet according to the present invention will be clear to those skilled in the art from the following detailed description of an embodiment thereof, with reference to the annexed drawings wherein:

[0020] FIGS. 1a-1f illustrate prior art electromagnets and their drawbacks;

[0021] FIG. 2 is a lateral view in longitudinal section along the midplane of an electromagnet according to the invention;

[0022] FIG. 3 is a bottom plan view, with a broken-away portion, of the electromagnet of FIG. 2;

[0023] FIG. 4 is a lateral view diagrammatically showing a moving apparatus that uses said electromagnet; and

[0024] FIG. 5 is a cross-sectional view along line V-V of FIG. 3.

DETAILED DESCRIPTION

[0025] Referring first to the prior art illustrated in FIGS. 1a to 1f, there is seen that a conventional electromagnet em may be formed by a polar yoke g having an inverted U shape with 2 solenoids a wound on cores n and North/South polarities (as illustrated in FIG. 1a), or an E shape rotated 90 clockwise with a single solenoid a wound on the central core n and South/North/South polarities (as illustrated in FIG. 1c). In both cases, such an electromagnet em has a strong laterally dispersed field l (FIGS. 1b, 1d) since its side panels f are made from non-magnetic material, and this makes it difficult to center the load c in the proximity of ferromagnetic members, such as stalls m, because of the lateral deviation caused by the attractive effect towards said members due to said dispersed field l (FIG. 1e).

[0026] Moreover, as shown in FIG. 1f, when moving bundles of tubes kept together by containment strappings, repulsive forces fr are generated between adjacent tubes since the tube surfaces, e.g. a central tube tc and two lateral tubes tl, are all polarized with the same sign thus tending to repel each other due to the repulsive effect and, consequently, to rotate the two external tubes tl in opposite directions.

[0027] FIGS. 2 and 3 show a novel electromagnet 1 according to the present invention in which the flux lines 2 extend only downwards in the direction of the load to be moved, whereas the laterally dispersed magnetic field is substantially absent.

[0028] More specifically, there is seen that the polar yoke of said electromagnet 1 has a shape corresponding to two aligned E-shaped yokes. In fact, there are provided two North polarity cores 3 on which two solenoids 4 are wound, received in suitable recesses, buried in insulating resins and preferably manufactured from copper wire strips in order to achieve the maximum fill factor and to obtain a compact size of the solenoids 4 and consequently of the ferromagnetic circuit formed around them, thus reducing to a minimum the weight and size of electromagnet 1.

[0029] Solenoids 4 are protected on the bottom by annular baffles 5 made from non-magnetic material, such as wear-resistant manganese steel, and the flux lines 2 exit from the enlarged polar shoes 6 of the two cores 3, pass through the ferromagnetic material of the load to be moved and re-enter through the faces of three enlarged polar shoes 7 of the South polarity poles 8, finally closing in cover 9 that connects cores 3 to poles 8, all these circuital members being obviously made from ferromagnetic material.

[0030] A novel aspect of the present electromagnet is given by the presence of the side panels 10 made from ferromagnetic material extending along both sides and passing next to cores 3 so as to magnetically connect the three poles 8 while being magnetically insulated from cores 3 in order to prevent magnetic short-circuiting. The thickness of the ferromagnetic side panels 10 is sized such that they are suitable to short-circuit substantially the whole lateral flux, therefore preventing the dispersion thereof and conveying it completely towards the polar shoes 7 of poles 8 and into the material to be magnetized thus actively contributing to the lifting of the latter.

[0031] In fact, in the present electromagnet 1 the active surface contacting the load consists of the whole bottom surface with the exception of the two annular baffles 5 made from non-magnetic material. As a consequence, a same magnetic attraction force is distributed over a greater surface area, which combined with the reduction in weight of electromagnet 1 results in a low specific pressure on the load surface thus eliminating the risk of surface damage.

[0032] The pattern of the flux lines 2 illustrated in FIGS. 2, 3 shows that even in the open field, i.e. without the presence of a load, the laterally dispersed flux is practically nothing. This is an essential aspect for positioning load c in the desired spot with electromagnet 1 without undergoing deviations even in the presence of stalls m of ferromagnetic material, thus perfectly matching the coordinates programmed by an automatic system without requiring the presence of personnel (FIG. 4).

[0033] Finally, as shown in the sectional view of FIG. 5, the flux lines 2 exiting the two North polarity cores 3 and closing in the South polarity side panels 10 not only eliminate the lateral dispersions but also create attractive forces fa between the lateral tubes tl and the central tube tc because the polarities that are generated on adjacent active surfaces have opposite signs. This attractive effect increases the anchoring strength under the same conditions with respect to a conventional electromagnet and does not produce an additional load on the containment strappings.

[0034] This allows to prevent the deformations of the tube bundles strappings and the subsequent risks of strapping failure and of mismatching of the positioning coordinates. As a consequence, electromagnets 1 according to the present invention can be used to build an automatic warehouse for tubular members, including strapped tube bundles.

[0035] It is clear that the above-described and illustrated embodiment of the electromagnet according to the invention is just an example susceptible to various modifications. In particular, the double-E shape with two cores 3, two solenoids 4 and three poles 8 is preferred, yet the addition of further E-shaped modules could be provided to increase the lifting capacity. For example, a larger electromagnet 1 could include three cores 3, three solenoids 4 and four poles 8.