JP2911905B2 - Electromagnetic pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention applies a traveling magnetic field to a conductive fluid from the outside,
The present invention relates to an electromagnetic pump that causes a pumping action of a fluid.

(Prior art) The basic principle of operation of an electromagnetic pump is to apply a current to a conductive fluid placed in a magnetic field and generate a force (Bo
by Force) to generate a pump action, based on Fleming's left-hand rule. When the magnetic flux density of the magnetic field is B and the current density in the fluid is J, the force F generated per unit volume of the fluid is expressed by the following equation.

F = J × B Electromagnetic pumps can be broadly classified into the following two types depending on the method of applying a current to the fluid.

(1) Based on the same principle as a DC motor, this is a method in which an electric current is directly applied to a fluid from the outside through an electrode in contact with the fluid. This is called a conduction type (conduction type).

(2) A method based on the same principle as that of an induction motor, in which a moving magnetic field is externally applied to a fluid to thereby induce a current in the fluid. This is called an induction type (induction type).

The present invention relates to the induction type (2), and more particularly to a three-phase induction type electromagnetic pump using three-phase alternating current.

In a three-phase induction type electromagnetic pump, three-phase AC windings are arranged in the order of each phase in the direction of flow of the electromagnetic pump, and when three-phase AC is applied to these windings, a traveling magnetic field is generated in the direction of fluid flow. Occur. If this traveling magnetic field is made to pass through a duct having a conductive fluid, a voltage is induced in the fluid by Fleming's right-hand rule, and an induced current flows. The induced current and some components of the traveling magnetic field act to form an electromagnetic force, which acts as a pump by receiving a force so that the fluid flows.

This electromagnetic force corresponds to the torque in the induction motor and the thrust in the linear motor.

Three-phase induction type electromagnetic pumps are roughly classified into the following two types in terms of structure.

(1) Flat linear electromagnetic pump The flat linear electromagnetic pump is
It is called FLIP (Flat Linear Induction Pump). The structural features include the following.

The duct is formed by a thin stainless steel plate to form a straight channel having a flat and rectangular cross section. Since the loop pipe outside the pump is circular, it is connected by a widening pipe in which the flow path shape gradually changes.

The stator that generates the traveling magnetic field is composed of a three-phase AC winding and a laminated iron core. The winding is fixed by placing opposing straight portions of a tortoise-shaped coil forming one loop on a plane in a groove of an iron core. The stator, which is a set of a winding and an iron core, is assembled so as to face each other across a duct.

Conventionally, the gap between the stator and the duct is thermally insulated by a heat insulating material so that the duct is not cooled.

Since the stator is divided into upper and lower parts as described above, the stator can be removed without cutting the pipes and ducts, so that there is an advantage that maintenance and inspection can be easily performed.

Because of these features and the same structure as a familiar electric machine such as a linear motor, it has hitherto been most often produced as an induction type electromagnetic pump.

(2) Annular Linear Electromagnetic Pump The annular linear electromagnetic pump is called ALIP (abbreviation of Annular Linear Induction Pump) because of its annular cross section. Due to the high reliability and safety of the duct structure, it is a mainstream electromagnetic pump in recent years.

Fig. 1 shows the basic structure of ALIP. The structural features include the following.

The duct is a concentric double pipe made of stainless steel and forms an annulus flow path. Since the duct shape is cylindrical and the strength is excellent, it can be said that the duct structure has high reliability.

The stator is provided outside the duct and includes a radial iron core and a ring-shaped coil.

Inside the inner duct is housed a laminated inner core for forming a magnetic circuit.

The coils of these electromagnetic pumps are arranged alternately according to the phase order in each phase group along the flow direction.
The groups of each phase are grouped together and electrically connected in series to form one series circuit, and each phase circuit is connected to a Y- or △ -shaped network as required. I have.

(Problems to be Solved by the Invention) Generally, in an AC machine, the number of parallel circuits of each phase group is freely selected to some extent as the degree of freedom in designing these connections. For example, if the number of parallel circuits is N for a design with one parallel circuit, the current will be N times but the voltage may be 1 / N times. Therefore, an optimal design according to the power supply and control was possible. Further, the formation of the multi-parallel circuit is performed by the connection between the coils, and therefore all the conductors in the coil belong to the same parallel circuit. However, in the case of the present electromagnetic pump, since there are iron core ends at the inlet and the outlet of the flow passage, among the coils constituting the parallel circuit, the coil 10 at the end and the other coils 11, 12 as shown in FIG. Since the impedances of the coils are different from each other, an imbalance of impedance occurs in a parallel circuit having the same phase as shown in FIG. Here, only the U phase is shown for easy understanding. When a voltage is applied to these, the load current differs for each parallel circuit, and the target current does not flow in one coil, and the target current or more flows in another coil, and the coil loss and the coil temperature rise. In addition, only a traveling magnetic field having a large distortion was obtained, and the electromagnetic force applied to the conductive fluid was not efficient.

Therefore, the connection of the coil must be designed with one parallel circuit, especially in a large-capacity electromagnetic pump in which unbalanced current is a problem. Therefore, there is no design freedom and a large-capacity machine can be used. The higher the operating voltage, the higher the operating voltage, causing problems in the reliability and economy of power supplies, coils, and the like.

The present invention has been made in view of the above problems,
In particular, it is an object of the present invention to provide a highly reliable electromagnetic pump free of unbalanced current by drastically increasing the degree of freedom in design by allowing the number of parallel circuits on the connection of a three-phase induction type electromagnetic pump to be arbitrarily selected. .

[Configuration of the invention]

(Means for Solving the Problems) In order to achieve the above object, in the electromagnetic pump of the present invention, a flow path of a conductive fluid is formed by an inner duct having an inner core and an outer duct having an outer core. At least one of a plurality of coils for forming a traveling wave magnetic field in the conductive fluid in the flow path is provided in each of at least one of a plurality of comb-shaped slots formed in at least an outer core of the core. In an electromagnetic pump using a three-phase alternating current as a power supply for the coil, the coil is wound from a plurality of independent conductors each having a lead portion at each end, and these conductors are formed in the coil by the conductors. A number of parallel circuits are formed, and the conductors are wound so that the respective parallel circuits have substantially the same impedance value, and the ports for introducing current from outside the conductors are formed. A pair of protrusions is formed in the coil by the number of the conductors.

(Operation) The present invention is configured as described above, and the conductors of all the circuits constituting the parallel circuit in each phase are housed in the same coil, so that the electrical condition for the slot position of each circuit is completely reduced. Since they can be the same, it is possible to eliminate the difference in impedance between the coils constituting the parallel circuit due to the difference in the slot position and the impedance imbalance of the parallel circuit, thereby eliminating the unbalanced current.

Example An example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of an essential part of an annular linear type electromagnetic pump. The duct is a stainless steel concentric double pipe composed of an inner duct 6 and an outer duct 5, and an annular flow path 2 is formed. Inside the inner duct 6, an inner core 4 for forming a magnetic circuit is accommodated. Outside duct 5
An outer iron core 3 is radially provided on the outer periphery of the coil, and a ring-shaped coil 1 is housed in a slot formed in the outer iron core.

Next, how to wind the conductor in the coil 1 will be described with reference to FIG.

FIG. 2 shows an example of a winding method in the case of three parallel circuits. The three parallel circuit coil 15 is formed by winding conductors 16, 17, and 18 three times each in a pancake shape, and The right row 20 is formed in a two-row configuration. In the figure, 21, 22, and 23 are conductors 1, respectively.
6 shows a section extending from the left column 19 to the right column 20 of 6, 17, and 18. The left row 19 and the right row 20 are finally unified into one
It is a book coil. FIG. 3 shows the integrated coil.
FIG. 15 shows a cross-sectional view when 15 is placed in the slot.

 Next, the operation and effect of this embodiment will be described.

The current flowing through the conductor 16 is the lead 16 of the conductor 16 in the left row 19.
After entering from a and rotating the left row 19 for one and a half turn, the conductor 16 flows into the right row 20 through the 21 from the left row 19 to the right row 20 of the conductor 16 exactly 180 degrees opposite to the outlet 16a. In addition, this right row 20
After one and a half rotations, the conductor 16 goes out to the lead portion 16b of the conductor 16 in the right row 20. As a result, the lead portion in the conductor 16 of the coil 15
16a and 16b can be taken out from the same place. Conductor 1
Apply the same winding method for 7 and 18 to 17a and 17
b, 18a and 18b can be taken out from the same place.
The conductors 16, 17, and 18 constituting the parallel circuit can be led out of the same location on the circumference of one coil 15 respectively.
FIG. 4 shows how the coil 15 thus constructed is exposed.

As described above, according to the present embodiment, it is possible to disperse the leads, and to disperse the space required for the connection between the coils and the connection, so that the electromagnetic pump itself can be downsized.

FIG. 5 shows a crossover between the coils in the case of three parallel circuits.
An example of connection by 27 is shown. In this way, if the coils of each phase can be formed by a parallel circuit, for example, even if one of the parallel circuits becomes defective, another circuit can be used, and the electromagnetic pump itself may not work at all. And the reliability of the electromagnetic pump is dramatically improved.

Further, in the winding method in one coil, as shown in FIG. 2, since the portion of the coil extending from the left row 19 to the right row 20 is dispersed, the loss of the height of the coil at the time of conducting the conductor is lost. Can be prevented, and the coil can be miniaturized most as the coil having the same number of parallel windings and the same number of turns.

As another embodiment, FIG. 6 shows how the coils 24, 25, and 26 are exposed when the number of parallel circuits is 2, 4, and 6.

Further, as shown in FIG. 7, two rows of pancake-shaped windings are connected on the outer peripheral side to form lead portions 29a and 29b, 30a and 30a.
b can be exposed from the same place, and it is possible to realize one coil 28 having windings of an arbitrary even number of rows.

〔The invention's effect〕

As described above, according to the present invention, the conductors of a plurality of circuits constituting the parallel circuit of each phase are housed in the same coil, so that the opening of the coil is dispersed regardless of the number of parallel circuits, The size of the coil can be reduced by dispersing the conductors, and the size and reliability of the electromagnetic pump can be greatly improved. In addition, since the number of parallel circuits can be arbitrarily selected, it is possible to design an optimal electromagnetic pump according to the power supply and control. Furthermore, suppression of unbalanced current due to the elimination of impedance imbalance between parallel circuits, suppression of extra loss of coil due to this current, local overheating of coil, etc., also improve pump reliability and performance from this aspect. It can greatly contribute to improvement.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an essential part of an annular linear type electromagnetic pump according to an embodiment of the present invention, FIG. 2 is a view showing a winding method of a conductor in a coil of FIG. 1, and FIG. FIG. 4 is a cross-sectional view of the conductor in the slot, FIG. 4 is a view showing the appearance of the coil 15 in FIG. 2, FIG. 5 is a view showing an example of connection between the coils of the coil 15 in FIG. 2, and FIG. ), (B), and (c) are diagrams showing the appearance of coil tapping when the number of parallel circuits is 2, 4, and 6, respectively.
FIG. 7 is an external view of a coil having four rows of horizontal conductors, FIG. 8 is a configuration diagram of a slot and a coil of a conventional electromagnetic pump, and FIG.
The figure shows a circuit diagram in which one phase is constituted by three parallel circuits in FIG. 1 ... coil, 2 ... conductive fluid flow path, 3 ... outer core, 4 ... inner core, 5 ... outer duct, 6 ... inner duct, 15 ... coil of three parallel circuits, 15a, 15b , 15c ... coil cross section, 16, 17, 18 ... conductors constituting a parallel circuit, 16a, 17a, 18a ... lead in the left row of conductors, 16b, 17b, 18b ... right row of conductors Outlet, 19: Left row of coil conductors, 20: Right row of coil conductors, 21, 22, 23 ...: Between left and right rows of conductors.

Claims (1)

(57) [Claims] A conductive fluid flow path is formed by an inner duct having an inner core and an outer duct having an outer core, and a traveling wave magnetic field is formed in at least one of the ducts in the conductive fluid in the flow path. A plurality of coils to be disposed in at least one of a plurality of comb-shaped slots formed in at least an outer core of the iron core, and the electromagnetic pump using a three-phase alternating current as a power source of the coil. The coil is wound from a plurality of independent conductors having protruding portions at both ends, and these conductors form parallel circuits in the coil by the number of the conductors, and each parallel circuit has substantially the same impedance value. Wherein the conductors are wound so as to have a plurality of conductors, and a pair of the lead portions for introducing a current from the outside of each conductor are formed in the coil by the number of the conductors. Amplifier.