Apparatus to generate magnetism

Abstract: An apparatus to generate magnetism comprises a plurality of magnetism-generating circuits (U1,U2,U3) which are cascaded with respect to each other. Each magnetism-generating circuit contains a coil member (Z1,Z2,Z3) to generate magnetism and a capacitor (C1,C2,C3) to provisionally store the current across said coil member. A conduction-controlling circuit (TS) which is to operate the magnetism-generating circuits in a prescribed order is also provided. With this arrangement an improved current efficiency and a stabilized operation can be attained even when used to generate high-power magnetic pulses at shortened pulse intervals.

Description: Embodiments of the present invention relate to an apparatus to generate magnetism, in particular, to an apparatus to generate magnetism which may attain an improved current efficiency, wherein a plurality of magnetism-generating circuits containing capacitors to provisionally store the current across a coil member are provided to repeatedly use the current. GB 2,156,609A describes an apparatus to generate magnetism where a coil member is energized with dc, which uses as shown in FIG.6 only one magnetism-generating circuit consisting of a coil member to generate magnetism, a series circuit containing a capacitor to provisionally store the current through the coil member, a first thyristor having a main current path connected in series with the series circuit, and a second thyristor having a main current path which is connected in parallel with the series circuit in such a manner that the first and second thyristors come into forward direction. Such an apparatus is much more superior in current efficiency to those which have been known previously because it repeatedly uses the current which has been once energized to coil member. This type of apparatus, however, has the drawbacks that when one uses it to generate high-power magnetic pulses, its insufficient current efficiency may increase in power consumption per unit of magnetism, as well as that its operation may become unstable as pulse intervals become shorter. Reference should also be made to DE-A-3,031,659 which describes an apparatus having a plurality of magnetism-generating circuits each comprising a series circuit containing a coil member and a capacitor to provisionally store the current across the coil member. Each circuit also comprises a thyristor in series with the series circuit. In view of the foregoing, a main object of embodiments of the present invention is to provide an apparatus to generate magnetism which attains an improved current efficiency and a stabilized operation even when used to generate high-power magnetic pulses at shortened pulse intervals. Embodiments of the present invention may solve the above described object with an apparatus to generate magnetism, comprising a plurality of magnetism-generating circuits, each magnetism-generating circuit containing a coil member to generate magnetism, a capacitor to provisionally store the current across said coil member and at least one thyristor characterised in that the apparatus comprises a conduction-controlling circuit (TS) which is to operate the magnetism-generating circuits in a prescribed order and by the magnetism-generating circuits which are cascaded with respect to each other by allowing the conduction-controlling circuit to successively operate the magnetism-generating circuits such that the current energizing the coil member of a magnetism-generating circuit and stored in the capacitor of that magnetism-generating circuit is further used to energize the coil member of the next magnetism-generating circuit. In the apparatus embodying the present invention, the current which has been energized twice to a coil member in one magnetism-generating circuit may be repeatedly used to energize another coil member in a following magnetism-generating circuit. Further by suitably operating the magnetism-generating circuits, one can stably obtain high-power magnetic pulses at shortened pulse intervals. The present invention will be more concretely explained hereinafter in conjunction with several embodiments which are however not intended in any way to limit the scope of the present invention. FIG.1 is a circuit which shows the electric constitutive part in an embodiment according to the present invention. FIG.2 shows the waveforms across coil members Z1, Z2 and Z3. FIG.3 is a circuit which shows the electric constitutive part in conventional apparatus to generate magnetism. FIG.4 is a top plane view of a coil member. FIG.5 is a side elevation view cut off along with the line X-X' in FIG.4. Throughout the Figures, the symbols or reference numerals Ul through U3 designate magnetism-generating circuits; DC, dc source; SCR1 through SCR6, thyristors; Z1 through Z3, coil members; Cl through C3, capacitors; TS, conduction-controlling circuit; A, A', B, B', C and C', waveforms across coil members Z1, Z2 and Z3; 1, circular member; 2, wire; 3, projected part; 4, heat-insulating material; and K, lead. FIG.1 is a circuit which shows the electric constitutive part in an embodiment according to the present invention. In the Figure, DC is a dc source which usually comprises a rectifier circuit having an input terminal connected with an ac source, and a smoothing circuit which is connected with an output terminal of the rectifier circuit to smooth and convert its output into dc. U1, U2 and U3 are magnetism-generating circuits and respective circuits comprise a series circuit of coil member Z1, Z2 or Z3 to generate magnetism and a capacitor C1, C2 or C3, a first thyristor SCR1, SCR3 or SCR5 having a main current path connected in series with the series circuit, and a second thyristor SCR2, SCR4 or SCR6 having a main current path which is connected in parallel with the first thyristor SCR1, SCR2 or SCR3 in such a manner that the first and second thyristors come into forward direction. The hot terminal of the dc source DC is connected with one terminal of the main current path of the first thyristor SCR1 in the magnetism-generating circuit U1, while the cold terminal as the return terminal is connected with the terminals of the capacitors C1, C2 and C3 in the magnetism-generating circuits U1, U2 and U3 and also with the terminals of the second thyristors SCR2, SCR4 and SCR6 having main current paths which are connected in parallel with the first thyristors SCR1, SCR3 and SCR5 in such a manner that the first and second thyristors come into forward direction. One terminal of the main current path of the first thyristor SCR3 in the magnetism-generating circuit U2 is connected between the coil member Z1 and capacitor C1 in the preceding magnetism-generating circuit U1, while one terminal of the main current path of the first thyristor SCR5 in the magnetism-generating circuit U3 is connected similarly between the coil member Z2 and capacitor C2 in the preceding magnetism-generating circuit U2. Thus in this embodiment the magnetism-generating circuits are cascaded each other so that the current which has been energized once to the coil member Z1 can be further energized to the following magnetism-generating circuits U2 and U3. The gates of the first and second thyristors SCR1 through SCR6 in the magnetism-generating circuits U1, U2 and U3 are connected with an output terminal of a conduction-controlling circuit TS. In summary, embodiments of the present invention comprise a plurality of magnetism-generating circuits, each circuit comprising a coil member which is to generate magnetism, a series circuit containing a capacitor which is to provisionally store the current across said coil member, a first thyristor which has a main current path connected in series with said series circuit, and a second thyristor having a main current path which is connected in parallel with said series circuit in such a manner that said first and second thyristors come in forward connection each other, wherein one terminal of the capacitor in each magnetism-generating circuit is connected with the return terminal of a dc source and one terminal of the main current path of the first thyristor in one magnetism-generating circuit is connected with an output terminal of said dc source, while in the remaining magnetism-generating circuits, one terminal of the first thyristor in each magnetism-generating circuit is connected between the coil member and capacitor in the preceding magnetism-generating circuit so that a conduction-controlling circuit which has an output terminal connected with the gates of the first and second thyristors in the following magnetism-generating circuit can bring them into conduction with the current across the coil member in the preceding magnetism-generating circuit. Now explaining the operation of this embodiment, when the dc source is ON and triggering signals from the conduction-controlling circuit TS are energized to the gate of the first thyristor SCR1 in the magnetism-generating circuit U1, a current flows from the dc source DC to the coil member Z1 through the main current path of the first thyristor SCR1. The waveform of the current across the coil member Z1 is as shown in FIG.2(A). The current which has been energized to the coil member Z1 charges the capacitor C1 and the conduction of the thyristor SCR1 is suspended when the voltage across the capacitor C1 exceeds a prescribed level. Then triggering signals from the conduction-controlling circuit TS are energized to the gate of the first thyristor SCR3 in the magnetism-generating circuit U2 and approximately at the same time triggering signals are energized to the gate of the second thyristor SCR2 in the magnetism-generating circuit U1. The charge which is present in the capacitor C1 at this time is energized to the coil member Z2 through the main current path of the first thyristor SCR3, then stored in the capacitor C2. The waveform of the current across the coil member Z2 is as shown in FIG.2(B). When the voltage across the capacitor C2 becomes equal to that across the capacitor C1, the thyristor SCR3 is brought into nonconduction. In the same way, triggering signals are subsequently energized to the gate of the first thyristor SCR5 in the magnetism-generating circuit U3 and approximately at the same time triggering signals are energized to the gate of the second thyristor SCR4 in the magnetism-generating circuit U2. The charge which has been stored in the capacitor C2 during this operation is energized to the coil member Z3 through the main current path of the first thyristor SCR5, then stored in the capacitor C3 for repeated use. The waveform of the current across the coil member Z3 is as shown in FIG.2(C). Thus, by allowing the conduction-controlling circuit TS to successively operate the magnetism-generating circuits U1, U2 and U3, a forward current and a diphasic current as shown in FIG.2 whose magnitude declines in time course continually flow into the coil members Z1, Z2 and Z3, thus generating a magnetism which has a waveform correspondent to those of the input currents. By allowing the conduction-controlling circuit to repeat the above described operation, the coil members Z1, Z2 and Z3 continuously generate a series of magnetic pulses which have such a waveform. Although this embodiment does not describe concretely, by suitably operating the conduction-controlling circuit TS, one can obtain series of pulses of different types which consist of magnetic fields of one direction, those of opposite directions or combination thereof. Further the number of the magnetism-generating circuits are not restricted to three and four or more circuits can be used, provided that coil members with low dc resistance values are used. There are provided no limitations in the shapes and structures of coil members as far as they generate a prescribed magnetism. However when used in magnetic therapy for human subjects, it is preferable to prepare coil members into shapes and structures which allow subjects to easily attach to desired sites, as well as reducing their possible fatigue at the sites to be treated due to the weight of coil members. FIGs.4 and 5 show an example of coil member which is useful in magnetic therapy for human subjects: FIG.4 shows its top plane view, while FIG.5, the side elevation view cut off along with the line X-X' in FIG.4. In FIGs.4 and 5, the reference numeral 1 designates a circular member which is prepared for respective subject's sites to be treated by forming plastic materials to suitable sizes. There is provided as shown in FIG.5 a groove along with the fringe of the circular member 1 and a wire 2 is wound many times along with the groove. The materials for the wire are usually copper, silver, aluminum or aluminum alloy which are covered with suitable insulating materials. Among these materials, light metals such as aluminum and aluminum alloy are preferable because they give coil members with remarkably decreased weights which would hardly cause fatigue even when used in magnetic therapy for human subjects. In a projected part 3 provided outside the circular member 1, a bimetal is enclosed and the winding ends of the wire 2 are connected with a lead K through the bimetal. As well known, bimetals comprise a temperature-sensing part and a switching part which operable in response to the temperature-sensing part. By providing the temperature-sensing part closely to a coil member to generate magnetism and inserting the switching part in the electric circuit including the coil member, one can prevent the coil member to overheat above a prescribed temperature during operation. In this example, as shown in FIG.5, the outside of the coil member is coated with a heat-insulating material such as plastic, glass fiber cloth or silicone rubber. This arrangement effectively prevents burns in subjects even when the coil member is overheated to some extent during operation. As explained above, embodiments of this invention may be superior in current efficiency and capable of stably generating high-power magnetic pulses at shortened pulse intervals because this invention uses a plurality of magnetism-generating circuits and operates them in a successive manner whereby currents which have been used once to energize coil members can be repeatedly used. The use of coil members with low resistances arises no remarkable voltage drops and much more improves current efficiency. The magnetism-generating apparatus embodying the present invention is useful as magnetism-generating means in magnetic therapy, as well as in the improvement of productivity of animals and plants, for example, domestic animal, poultry, microorganism, cell, fruit plant, flower and vegetable.

Claims: An apparatus to generate magnetism, comprising a plurality of magnetism-generating circuits (U 1 , U 2 , U 3 ), each magnetism-generating circuit containing a coil member (Z 1 , Z 2 , Z 3 ) to generate magnetism, a capacitor (C 1 , C 2 , C 3 ) to provisionally store the current across said coil member and at least one thyristor (SCR 1 , SCR 3 , SCR 5 ) characterised in that the apparatus comprises a conduction-controlling circuit (TS) which is to operate the magnetism-generating circuits in a prescribed order and by the magnetism-generating circuits which are cascaded with respect to each other by allowing the conduction-controlling circuit to successively operate the magnetism-generating circuits such that the current energizing the coil member of a magnetism-generating circuit and stored in the capacitor of that magnetism-generating circuit is further used to energize the coil member of the next magnetism-generating circuit. The apparatus of Claim 1, wherein each of said magnetism-generating circuits (U 1 , U 2 , U 3 ) comprises a series circuit containing a coil member (Z 1 , Z 2 , Z 3 ) and a capacitor (C 1 , C 2 , C 3 ), a first thyristor (SCR 1 , SCR 3 , SCR 5 ) having a main current path connected in series with said series circuit; and a second thyristor (SCR 2 , SCR 4 , SCR 6 ) having a main current path which is connected in parallel with said series circuit in such a manner that said first and second thyristors come in forward direction each other. The apparatus of Claim 2, wherein one terminal of the capacitor in each magnetism-generating circuit is connected with the return terminal of a dc source (DC) and one terminal of the main current path of the first thyristor in one magnetism-generating circuit is connected with an output terminal of said dc source (DC), while in the remaining magnetism-generating circuits, one terminal of the first thyristor in each magnetism-generating circuit, is connected between the coil member and capacitor in the preceding magnetism-generating circuit so that the conduction-controlling circuit which has an output terminal connected with the gates of the first and second thyristors in the following magnetism-generating circuit can bring them into conduction with the current across the coil member in the preceding magnetism-generating circuit. The apparatus of any preceding claim, wherein said coil members (Z 1 , Z 2 , Z 3 ) generate a couple of magnetic fields which are different in direction to each other when the magnetism-generating circuits are energized. The apparatus of any preceding claim, wherein said coil members are made with aluminium or aluminium alloy. The apparatus of any preceding claim, wherein a temperature-sensing means (3) is provided closely to the coil member and a switching means which is operable in response to said temperature-sensing means is provided in the circuit containing the coil member so as to prevent the coil member from overheating above a prescribed temperature during operation. The apparatus of any preceding claim, wherein said coil members are covered with a heat-insulating material.

Inventors: MASAKI KAZUMI, MASAKI, KAZUMI
Applicants: HAYASHIBARA KEN, HAYASHIBARA, KEN
Application year: 1995
Main classification: H01F7
IPC codes: A61N2, G05F1, A01K67, A01G7, H01F7