JP2016041003A - Solenoid pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solenoid pump capable of reducing a negative electromagnetic force.SOLUTION: The solenoid pump includes: a duct which has a circular flow pass formed for allowing a conductive fluid to flow along an axial direction; plural circular exciting coils provided along in a diameter direction on the peripheral surface of the duct; and an iron core which is formed to cover the periphery surface of the duct. In the plural exciting coils, at least a part of the end part exciting coils, which are exciting coils closest to the end part of the duct, are exposed from the iron core, and the other exciting coils are disposed in the iron core.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to an electromagnetic pump.

  Conventionally, an electromagnetic pump that causes a conductive fluid such as a liquid metal to flow using electromagnetic force has been put into practical use. The electromagnetic pump is used, for example, as a reactor circulation pump. FIG. 10 is a cross-sectional view showing a schematic configuration of a conventional double stator electromagnetic pump 100. The electromagnetic pump 100 includes an annular duct 102 having a conductive fluid flow path formed therein, an iron core 103 provided around the duct 102, and excitation coils 111, 112, 113 covered by the iron core 103. And have.

  By flowing three-phase alternating current through the excitation coils 111, 112, and 113, a moving magnetic field is generated around the excitation coil. When this moving magnetic field passes through the conductive fluid in the duct 102, an induced current is generated. The electromagnetic force generated by the interaction between the induced current and the magnetic field is used to drive the conductive fluid from the inlet to the outlet along the axial direction of the electromagnetic pump.

  Since the magnetic permeability of the iron core 103 is extremely large (about several thousand times) compared to the atmosphere, the magnetic flux concentrates in the iron core 103, and the magnetic flux density B1 in the iron core 103 is significantly higher than the magnetic flux density B2 in the atmosphere. . Thereby, a large number of magnetic fluxes pass through the conductive fluid in the duct 102, and the driving force of the conductive fluid increases. On the other hand, it is known that the efficiency of the electromagnetic pump is reduced by the so-called “end effect”.

  When the conductive fluid flowing in the duct 102 reaches the boundary surface S of the iron core 103 where the magnetic flux density changes abruptly, an induced current flows to cancel the change in the magnetic flux density before and after the boundary surface S. Due to the interaction between the induced current and the magnetic field, an electromagnetic force (hereinafter also referred to as “negative electromagnetic force”) opposite to the driving direction of the conductive fluid is generated. This reduction in the driving force of the conductive fluid due to the negative electromagnetic force is an end effect, which has been known to reduce the efficiency of the electromagnetic pump.

JP-A-8-98503

  The problem to be solved by the present invention is to provide an electromagnetic pump capable of reducing negative electromagnetic force.

  The electromagnetic pump according to the embodiment includes a duct in which an annular flow path for allowing a conductive fluid to flow in the axial direction is formed inside, and an annular shape provided in a radial direction on the circumferential surface of the duct. A plurality of exciting coils and an iron core provided so as to cover the peripheral surface of the duct. Of the plurality of excitation coils, at least a part of the end excitation coil that is the excitation coil closest to the end of the duct is exposed from the iron core, and the other excitation coils are disposed in the iron core.

It is sectional drawing which shows the schematic structure of the electromagnetic pump 1 which concerns on 1st Embodiment. It is a figure which shows the simulation result which calculated | required the electromagnetic force which acts on the electroconductive fluid which flows through the electromagnetic pump 1 by two-dimensional analysis. It is sectional drawing which shows schematic structure of 1 A of electromagnetic pumps which concern on the modification of 1st Embodiment. It is sectional drawing which shows schematic structure of the electromagnetic pump 1B which concerns on 2nd Embodiment. It is sectional drawing which shows schematic structure of 1 C of electromagnetic pumps which concern on the modification of 2nd Embodiment. It is sectional drawing which shows schematic structure of electromagnetic pump 1D which concerns on 3rd Embodiment. It is sectional drawing which shows schematic structure of the electromagnetic pump 1E which concerns on 4th Embodiment. It is sectional drawing which shows schematic structure of the electromagnetic pump 1F which concerns on the modification of 4th Embodiment. It is sectional drawing which shows schematic structure of the electromagnetic pump 1G which concerns on 5th Embodiment. It is sectional drawing which shows the schematic structure of the conventional electromagnetic pump 100. FIG.

  Hereinafter, an electromagnetic pump according to an embodiment will be described with reference to the drawings.

(First embodiment)
An electromagnetic pump 1 according to a first embodiment of the present invention will be described.

  As shown in FIG. 1, the electromagnetic pump 1 includes a duct 2 having a flow path through which a conductive fluid flows, and a plurality of exciting coils that generate a moving magnetic field and cause the conductive fluid in the duct 2 to flow by electromagnetic force ( Three-phase alternating current coils) 11a to 19a, 11b to 19b, and an iron core 3 for efficiently guiding the moving magnetic field into the duct 2.

  Thus, the electromagnetic pump 1 is a double stator type electromagnetic pump having the exciting coils 11 a to 19 a on the outside of the duct 2 and 11 b to 19 b on the inside of the duct 2. The electromagnetic pump 1 may be a single stator type electromagnetic pump.

  As shown in FIG. 1, the duct 2 has an annular flow path formed therein for allowing the conductive fluid to flow along the axial direction of the duct 2. The conductive fluid is, for example, a liquid metal such as liquid sodium or mercury. The end 2c of the duct 2 is the outlet side (outlet) of the electromagnetic pump 1, and the end 2d of the duct 2 is the inlet side (inlet) of the electromagnetic pump 1.

  The exciting coils 11 a to 19 a and 11 b to 19 b are annular coils provided on the peripheral surface of the duct 2. More specifically, the exciting coils 11 a to 19 a are provided on the outer peripheral surface 2 a of the duct 2 along the radial direction of the duct 2, and the exciting coils 11 b to 19 b are disposed on the inner peripheral surface 2 b of the duct 2 in the radial direction of the duct 2. It is provided along.

  A three-phase alternating current flows through the excitation coils 11a to 19a and 11b to 19b, and a moving magnetic field is generated around the excitation coil. More specifically, a U-phase AC voltage is applied to the excitation coils 11a, 11b, 14a, 14b, 17a, and 17b, and a V-phase AC voltage is applied to the excitation coils 12a, 12b, 15a, 15b, 18a, and 18b. Then, a W-phase AC voltage is applied to the excitation coils 13a, 13b, 16a, 16b, 19a, 19b.

  The number of exciting coils provided in the electromagnetic pump 1 is not limited to the number shown in FIG. Moreover, you may generate | occur | produce a moving magnetic field using polyphase alternating currents other than three phases.

  In the following description, among the excitation coils 11a to 19a and 11b to 19b, the excitation coil closest to the end 2c of the duct 2 (that is, the excitation coils 11a and 11b) and the excitation coil closest to the end 2d (that is, The exciting coils 19a and 19b) are also referred to as “end exciting coils”.

  The iron core 3 is provided so as to cover the peripheral surface of the duct 2. More specifically, as shown in FIG. 1, the iron core 3 includes an outer iron core 3a and an inner iron core 3b. The outer iron core 3 a covers the outer peripheral surface 2 a of the duct 2, and the inner iron core 3 b covers the inner peripheral surface 2 b of the duct 2. In FIG. 1, the phantom line V indicates the outline of the iron core of the conventional electromagnetic pump.

  In the electromagnetic pump 1 according to the first embodiment, as shown in FIG. 1, excitation coils 11 a and 11 b that are end excitation coils are exposed from the iron core 3, and other excitation coils are arranged in the iron core 3. . That is, only the exciting coils 11 a and 11 b are not covered with the iron core 3 and are exposed on the end surface 3 c of the iron core 3. Thereby, as shown in FIG. 1, the magnetic flux does not converge in the iron core 3 in the vicinity of the outlet of the electromagnetic pump 1 but diffuses toward the outlet of the electromagnetic pump 1. For this reason, the magnetic flux density gradually decreases as the distance from the end surface 3 c of the iron core 3 increases. That is, the magnetic flux density penetrating the duct 2 changes gently along the axial direction of the electromagnetic pump. Therefore, according to the first embodiment, negative electromagnetic force can be reduced.

  FIG. 2 shows the result of obtaining the electromagnetic force acting on the conductive fluid flowing through the electromagnetic pump 1 by two-dimensional analysis. It can be seen that the negative electromagnetic force is greatly reduced on the outlet side of the electromagnetic pump 1.

  Further, according to the first embodiment, the weight of the iron core is reduced as compared with the conventional electromagnetic pump, so that the electromagnetic pump can be reduced in weight.

  The excitation coils 11 a and 11 b are not limited to being exposed from the iron core 3 as shown in FIG. 1, and at least a part of the excitation coils 11 a and 11 b may be exposed from the iron core 3. For example, the lower half of the excitation coils 11 a and 11 b may be disposed in the iron core 3, or only the upper surfaces of the excitation coils 11 a and 11 b may be exposed from the iron core 3.

  Further, in the above description, the end excitation coils (excitation coils 11a and 11b) on the outlet side of the electromagnetic pump 1 are exposed from the iron core 3, but the end excitation coils (excitation coils 19a and 19b) on the inlet side are exposed. It may be exposed from the iron core 3. Moreover, the end excitation coils on both the outlet side and the inlet side of the electromagnetic pump 1 may be exposed from the iron core 3.

  In the case of a double stator type electromagnetic pump, one of the end excitation coils may be covered with the iron core 3. For example, either one of the excitation coils 11 a and 11 b may be disposed inside the iron core 3. In this case, it is preferable that the exciting coil 11 b be covered with the iron core 3 because the outer iron core 3 a is deleted rather than the inner iron core 3 b to contribute to weight reduction of the entire iron core 3.

  Next, a modification according to the first embodiment will be described with reference to FIG.

(Modification)
In the electromagnetic pump 1 </ b> A according to the modified example, the excitation coil 11 a is disposed in an extended iron core 3 a 1 extended from the iron core 3 as shown in FIG. 3. By providing the extension iron core 3a1, the magnetic flux released from the end surface 3c of the iron core 3 to the atmosphere converges toward the extension iron core 3a1 as shown in FIG. it can. In addition, the spread of the magnetic field can be controlled by changing the axial length of the extension core 3a1.

  Therefore, according to the present modification, the magnetic flux density is gradually changed to reduce the negative electromagnetic force, and the magnetic flux leaking to the outside of the electromagnetic pump can be reduced to suppress the decrease in the efficiency of the electromagnetic pump. it can.

(Second Embodiment)
Next, an electromagnetic pump 1B according to a second embodiment of the present invention will be described with reference to FIG. In FIG. 4, the same components as those in FIG. One of the differences between the second embodiment and the first embodiment is the presence or absence of the claw iron core 4. Hereinafter, the second embodiment will be described focusing on the differences.

  As shown in FIG. 4, the electromagnetic pump 1 </ b> B according to the second embodiment further includes a claw iron core 4 in addition to the duct 2, the excitation coils 11 a to 19 a, 11 b to 19 b, and the iron core 3. The claws iron core 4 is provided on each of the outer iron core 3a and the inner iron core 3b. The claw iron core 4 may be formed integrally with the iron core 3 or may be formed as a separate body and then fixed to the iron core 3.

  As shown in FIG. 4, the claws iron core 4 includes a first iron core portion 4 a that rises from an end face 3 c where the exciting coils 11 a and 11 b are exposed, and a second iron core 4 a that extends from the first iron core portion 4 a toward the duct 2. And an iron core portion 4b.

  The first iron core portion 4a is formed in an annular shape along the radial direction of the excitation coils 11a and 11b. The second iron core portion 4b is formed so as not to cover all the exciting coils 11a and 11b. That is, you may make it the 2nd iron core part 4b cover a part of exciting coil 11a, 11b.

  In addition, it is preferable that the front-end | tip part of the 2nd iron core part 4b is formed in the curved surface shape which does not have a corner | angular part, as shown in FIG.

  Further, the claw iron core 4 is not limited to be formed continuously in an annular shape along the radial direction of the excitation coils 11 a and 11 b, and may be formed so as to be partially interrupted in the radial direction of the duct 2.

  By providing the claw iron core 4 on the iron core 3, as shown in FIG. 4, the magnetic flux is released from the tip of the claw iron core 4, spreads by passing through the atmosphere, and then spreads to the other second iron core portion 4b. Converge. By once diffusing the magnetic flux in this way, the magnetic flux leaking outside the electromagnetic pump 1B can be reduced while gently changing the magnetic flux density penetrating the duct 2 along the axial direction of the electromagnetic pump.

  Therefore, according to the second embodiment, it is possible to reduce the negative electromagnetic force while suppressing a decrease in the efficiency of the electromagnetic pump.

  Next, a modification according to the second embodiment will be described with reference to FIG.

(Modification)
As shown in FIG. 5, in the electromagnetic pump 1C according to the modification, the claw iron core 4 is provided on the outer iron core 3a, and the inner iron core 3b covers the exciting coil 11b. Even if it is such a structure, the effect similar to 2nd Embodiment can be acquired. In contrast to the configuration shown in FIG. 5, the claw iron core 4 may be provided on the inner iron core 3b so that the outer exciting coil 11a is covered with the outer iron core 3a.

(Third embodiment)
Next, an electromagnetic pump 1D according to a third embodiment of the present invention will be described with reference to FIG. In FIG. 6, the same components as those in FIG. One of the differences between the third embodiment and the first embodiment is the presence or absence of the low magnetic permeability core 5. Hereinafter, the third embodiment will be described focusing on the differences.

  As shown in FIG. 6, the electromagnetic pump 1 </ b> D according to the third embodiment further includes a low-permeability iron core 5 that is provided on the end surface 3 c of the iron core 3 where the exciting coils 11 a and 11 b are exposed and covers the end surface 3 c. ing. The low permeability iron core 5 is made of a material having a permeability larger than that of air and smaller than that of the iron core 3.

  Note that the low magnetic permeability core 5 may partially cover the end surface 3 c of the iron core 3.

  By providing the low permeability iron core 5 on the iron core 3, the magnetic flux is more easily diffused in the low permeability iron core 5 than in the iron core 3. For this reason, the magnetic flux density of the low permeability iron core 5 is lower than the magnetic flux density of the iron core 3. On the other hand, since the magnetic permeability of the low magnetic permeability core 5 is larger than that of air, the magnetic flux density of the low magnetic permeability core 5 is higher than the magnetic flux density in air. By providing the low magnetic permeability core 5, it is possible to prevent a rapid change in magnetic flux density before and after the end face 3 c of the core 3. That is, the magnetic flux density penetrating the duct 2 can be gradually changed along the axial direction of the electromagnetic pump.

  Therefore, according to the third embodiment, negative electromagnetic force can be reduced.

  Furthermore, according to the third embodiment, by providing the low-permeability iron core 5, the magnetic flux leaking to the outside of the electromagnetic pump is reduced as compared with the first embodiment. can do.

(Fourth embodiment)
Next, an electromagnetic pump 1E according to a fourth embodiment of the present invention will be described with reference to FIG. In FIG. 7, the same components as those in FIG. One of the differences between the fourth embodiment and the first embodiment is the presence or absence of a case 6 with an iron core. Hereinafter, the fourth embodiment will be described focusing on the differences.

  As shown in FIG. 7, the electromagnetic pump 1 </ b> E according to the fourth embodiment further includes a case 6 with an iron core provided on the end surface 3 c of the iron core 3 where the exciting coils 11 a and 11 b are exposed. The case 6 with an iron core is made of a nonmagnetic material such as ceramic. A plurality of spherical iron cores 7 are packed inside the case 6 containing the iron core. In FIG. 7, the case 6 with iron core is shown through.

  Even if the magnetic permeability of the spherical iron core 7 is approximately the same as that of the iron core 3, there is a gap between the spherical iron cores 7, so that the substantial permeability of the case 6 with the iron core is smaller than that of the iron core 3. By changing the shape and size (diameter, etc.) of the spherical iron core 7 and the porosity in the iron case 6, the substantial magnetic permeability of the iron case 6 can be controlled.

  By providing the iron core containing case 6 on the iron core 3, the same effects as those of the third embodiment can be obtained without using the low permeability iron core 5 described in the third embodiment. That is, as shown in FIG. 7, since the substantial magnetic permeability of the case 6 with the iron core is smaller than that of the iron core 3, the magnetic flux easily diffuses in the case 6 with the iron core and the magnetic flux density is lower than that of the iron core 3. Thereby, the rapid change of the magnetic flux density before and behind the end surface 3c of the iron core 3 can be prevented, and the magnetic flux density penetrating the duct 2 can be gradually changed along the axial direction of the electromagnetic pump.

  Therefore, according to the fourth embodiment, negative electromagnetic force can be reduced.

  Furthermore, according to 4th Embodiment, since the magnetic flux which leaks outside the electromagnetic pump reduces compared with 1st Embodiment by providing the case 6 with an iron core, the fall of the efficiency of an electromagnetic pump is suppressed. be able to.

  As shown in FIG. 7, the electromagnetic pump 1 </ b> E may further include a tubular iron core 8 that penetrates the case containing the iron core in the thickness direction and is wound around the duct 2. Thereby, since the magnetic flux leaking outside the electromagnetic pump is further reduced, it is possible to further suppress the reduction in the efficiency of the electromagnetic pump. The permeability of the tubular core 8 may be the same as that of the core 3.

  Further, a plurality of cases 6 with iron cores may be stacked and provided on the iron core 3. For example, a case containing an iron core having different substantial magnetic permeability is prepared, and the cases containing the iron core are laminated so that the substantial magnetic permeability of the case containing the iron core provided at a position distant from the end surface 3c of the iron core 3 becomes smaller. May be.

  Next, a modification according to the fourth embodiment will be described with reference to FIG.

(Modification)
In the electromagnetic pump 1F according to the modified example, as shown in FIG. 8, a plurality of plate-shaped cores 9 are packed inside the case 6 containing the core. In addition, in order to adjust the substantial magnetic permeability of the case 6 with the iron core to a desired value, the plate-like iron cores 9 may be laminated in a staggered manner (see FIG. 8) or may be laminated in a stepped manner.

  Also according to the configuration of this modification, the same effects as those of the fourth embodiment can be obtained. Moreover, according to this modification, the magnetic permeability can be adjusted relatively easily by changing the characteristics (planar shape, area, thickness, etc.) of the plate-like iron core 9 and the lamination method.

(Fifth embodiment)
Next, an electromagnetic pump 1G according to a fifth embodiment of the present invention will be described with reference to FIG. In FIG. 9, the same components as those in FIG. One of the differences between the fifth embodiment and the first embodiment is the spacing between the exciting coils. Hereinafter, the fifth embodiment will be described focusing on the differences.

  In the electromagnetic pump 1G according to the fifth embodiment, the interval L1 is larger than the interval L2, as shown in FIG. Here, the interval L1 is an interval between the exciting coil 11a and the first adjacent exciting coil 12a adjacent to the exciting coil 11a in the longitudinal direction of the duct 2. The interval L2 is an interval between the first adjacent excitation coil 12a and the second adjacent excitation coil 13a adjacent to the first adjacent excitation coil 12a in the longitudinal direction.

  By making the interval L1 larger than the interval L2, the magnetic flux density in the interval L1 is reduced. Thereby, the change of the magnetic flux density before and after the end surface 3c of the iron core 3 can be further alleviated.

  Therefore, according to the fifth embodiment, negative electromagnetic force can be reduced.

  In each of the above embodiments, the double stator type electromagnetic pump has been described. However, the present invention is not limited to this, and a single stator type electromagnetic pump in which an excitation coil is provided on either the outside or the inside of the duct. It can also be applied to electromagnetic pumps.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

1,1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 100 Electromagnetic pump 2,102 Duct 2a Outer peripheral surface 2b (Duct) Inner peripheral surface 2c, 2d End 3,103 Iron core 3a outer iron core 3b inner iron core 3a1 extension iron core 3c end face 4 claw iron core 4a first iron core portion 4b second iron core portion 5 low magnetic permeability iron core 6 case containing core 7 spherical iron core 8 tubular iron core 9 cores 11a, 11b, 12a , 12b, 13a, 13b Excitation coils 14a, 14b, 15a, 15b, 16a, 16b Excitation coils 17a, 17b, 18a, 18b, 19a, 19b Excitation coils 111, 112, 113 Excitation coils L1, L2 (between excitation coils) Spacing S Boundary surface V (line of conventional electromagnetic pump) Virtual line

Claims (8)

A duct formed therein with an annular flow path for flowing the conductive fluid along the axial direction;
A plurality of annular exciting coils provided along the radial direction on the circumferential surface of the duct;
An iron core provided to cover the circumferential surface of the duct;
With
Among the plurality of excitation coils, at least a part of the end excitation coil that is the excitation coil closest to the end of the duct is exposed from the iron core, and the other excitation coils are disposed in the iron core. And electromagnetic pump.   One of the first end excitation coil provided on the outer peripheral surface of the duct and the second end excitation coil provided on the inner peripheral surface of the duct is an extension extended from the iron core. The electromagnetic pump according to claim 1, wherein the electromagnetic pump is disposed in an iron core.   It further includes a claw iron core having a first iron core portion that rises from an end surface of the iron core from which the end excitation coil is exposed, and a second iron core portion that extends from the first iron core portion toward the duct. The electromagnetic pump according to claim 1.   2. The low-permeability iron core according to claim 1, further comprising a low-permeability iron core made of a material having a permeability larger than that of air and smaller than that of the iron core and covering the end face of the iron core where the end excitation coil is exposed. Electromagnetic pump.   2. The electromagnetic pump according to claim 1, further comprising a case containing a non-magnetic iron core provided on an end face of the iron core where the end excitation coil is exposed and having a plurality of spherical iron cores packed therein.   The electromagnetic pump according to claim 5, further comprising a tubular iron core that penetrates the case containing the iron core in a thickness direction and is wound around the duct.   2. A case with a non-magnetic iron core, which is provided on an end surface of the iron core where the end excitation coil is exposed and is packed in a state where a plurality of plate-like iron cores are stacked, is further provided. The electromagnetic pump described in 1.   The first interval between the end excitation coil and the first adjacent excitation coil adjacent to the end excitation coil in the longitudinal direction of the duct is the first adjacent excitation coil and the first adjacent excitation coil. The electromagnetic pump according to claim 1, wherein the electromagnetic pump is larger than a second interval between a second adjacent excitation coil adjacent to the adjacent excitation coil in the longitudinal direction.

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