KR20000018975A - Annular linear induction electronic punp with uniform gap between cores - Google Patents

Abstract

PURPOSE: An annular linear induction electronic pump is provided to minimize the leakage of magnetic flux, and to improve the driving efficiency of pumping by leading the uniform magnetic flux of radius direction into an inner core. CONSTITUTION: An annular linear induction electronic pump comprises: an outer core(1); an inner core(2); a duct(3); a coil(4); a spacer(5); a square supporting bar(8); a side supporting disc(9); a coil supporting ring(10); and a ferromagnetic plate(11). Herein, the outer core is: arranged to uniformly maintain a gap between the outer core and the inner core according to the circumference of the duct; to minimize the leakage of magnetic flux by laminating the ferromagnetic plate according to the circumference of the duct; to induce a uniform magnetic field of radius direction according to the circumference into the inner core; and assembled the distance between the inner upper face of a slot(7) of the outer core and the outer face of the electromagnetic coil uniformly.

Description

Circular section linear induction pump with uniform intercore clearance

The present invention relates to an annular cross-sectional linear induction electron pump having a uniform intercore gap, and is a key component of an induction electron pump used to transfer hot molten liquid metal through a circulation pipe or to lift it from a storage tank. The present invention relates to a circular cross-section linear induction pump designed to maintain a uniform gap between the outer and inner cores of a pump electromagnet and consequently to improve the pump operation efficiency due to an even magnetic gap in the circumferential direction.

The annular cross-section linear induction pump has a coaxially arranged non-magnetic metal pipe of different diameters as shown in FIG. 1 to form a duct with a constant width of the annular cross section spaced by a spacer, and the small diameter pipe constituting the duct. Generates a time-varying magnetic field in the axial and radial directions from the inner and outer cores formed by radially arranging ferromagnetic silicon steel plates with large magnetic permeability (relative magnetic permeability ≥10,000) inside and outside the large diameter pipe. It is configured to drive by using the induced current in the circumferential direction.

As shown in the right sectional view of FIG. 1, the inner core 2 is formed by cutting and stacking thin silicon steel sheets differently in width to radially guide the magnetic field from the outer core 1. 1) is composed of the same width of the silicon steel sheet is laminated to a certain thickness, made of several bundles and arranged radially so as to be a regular polygon when viewed in the longitudinal direction is configured to guide the magnetic field to the inner core (2).

In the conventional circular cross-section linear induction pump, four to eleven outer core bundles are produced to generate radial magnetic flux, and are arranged at equal intervals on the large diameter pipe circumference constituting the duct, so that a regular polygonal cross section is formed. Therefore, a magnetic path is formed toward the inner core inserted into the small diameter pipe. (US Patent 4,828,459 (May 9, 1989), Japanese Patent Application Laid-Open No. 60-70959 (April 22, 1985), Japanese Patent Application Laid-Open No. 59-47713 (March 17, 1984), Japanese Patent Application Laid-Open No. 59-2563 ( 1984. 1. 9), Japanese Patent Laid-Open No. 59-76166 (1984. 5. 1))

Therefore, the problems that may occur according to the above-described external core manufacturing are as follows.

In view of the fact that the electromagnetic pump uses a strong magnetic field as the basic principle of driving, the outer core, whose longitudinal section is a regular polygon, is axially symmetrical in geometry, but the vertex portion of the regular polygon (mainly hexagonal or regular octagonal) formed by the bundles of the external cores. Leakage of magnetic field and the width of the circular cross-sectional flow path (the ring-shaped flow path cross-section formed by two coaxial pipes of different diameters) are constant, but the core between the outer and inner cores having a regular polygonal shape The gap becomes wider towards the vertex of the regular polygon, resulting in no uniform magnetic field maintained in the circumferential direction. This causes a nonuniformity in the circumferential direction in the actual liquid metal flow and acts as a factor that inhibits a constant pumping drive. Moreover, in the case of a pump where the outer core bundles are spaced apart and the portion of the outer core laminated with silicon steel is excluded, a transverse edge effect occurs, which causes a drastic drop in pumping efficiency. (Japanese Patent Laid-Open No. 60-70959 (April 22, 1985), Japanese Patent Laid-Open No. 59-76166 (May 1, 1984))

In practice, the distribution of magnetic force lines for a pump configured to maintain a uniform inter-gap spacing with a circular core and a pump with a wider gap in the vicinity of the octagonal vertex by the arrangement of the octagonal core are shown in FIGS. 3 and 4. It was. In this case, in view of the symmetry of the pump, the magnetic field lines are shown in the plane corresponding to one-fourth of the pump cross-section A-A 'of FIGS. 1 and 2. 3 and 4 are the following dimensionless governing equations derived from Ampere law, Faraday's law and Ohm's law in the annular cross-sectional flow path of a pump having a sinusoidal applied magnetic field and a constant flow rate,

R _m = μ ₀ σ R ₀ V ₀ (magnetic reynolds number)

The spatial distribution of the radial and circumferential magnetic fields is plotted on a two-dimensional Cartesian coordinate plane with respect to a specific view.

In FIG. 3, the magnetic field distribution deviates from the radial direction in the region near the octagonal vertex (approximately y> 0.2), thereby reducing the resulting electromagnetic force. On the other hand, due to the octagonal core arrangement, the core gap is widened on the average, thereby reducing the magnitude of the magnetic field value and consequently reducing the driving efficiency of the pump. In order to find out the effect of improving the function of the circular cross-section linear induction electron pump according to the present invention in terms of pumping driving efficiency, the case of the flow rate 60 1 / min class electron pump is shown as a specific value as follows.

here,

: Winding coefficient

: Slip [1- (average flow rate / synchronous speed)]

: Specific resistance of conductor coil

: Number of slots / phase / stimulus

Slot pitch / slot width

: Number of phases of input power

: Electrical conductivity of metal fluid

Core gap

: Slot-Filling Factor (0.5 -0.6)

Slot Depth / Slot Width

Stimulus pitch

: Magnetic permeability in vacuum (= 4π × 10 ^-7 H / M)

Input frequency

In calculating the efficiency, the shape of the outside of the duct in the conventional electric pump appears as a regular polygon due to the arrangement of the outer core, and the unevenly spaced core gap is selected by converting the diameter of the circle corresponding to the same area into the average core gap. Calculated.

Comparison of conventional and inventive pump efficiencies

In the winding of the coil, the distance between the outermost surface of the coil and the inside of the outer core slot inserted into the outer core slot due to the outer core, which is not composed of the same curvature of the coil, is non-uniform, so as to actually finish the assembly of the coil bundle. In the pump structure having a free space for the winding number of the coil is reduced to secure the minimum distance of the free space. Considering that the pumping force is obtained in proportion to the square of the coil winding number, the reduction in the number of windings acts as a factor of lowering the pumping force.

According to the present invention having the configuration as described above, the outer core 1 has a circular arc shape that matches the radius of curvature of the duct below and above the outer core 1, as shown in FIG. 5, on both sides of the outer core 1. The ferromagnetic plates are laminated so that the width gradually decreases gradually, and then the cut surfaces are coated with a ceramic inorganic adhesive to maintain electrical insulation at a high temperature and the binding of the formed cores. Then, the end faces are assembled and finished by the square support (8). The ears are configured to be cut into a fan-like shape, and eight are made to be arranged radially in the circumferential direction, so as to be combined with the side support disk 9 to form a pump structure.

The outer core 1 manufactured in the same way as the curvature of the duct coincides with the curvature of the electromagnet coil 4 having the same curvature as the duct, so that the outer part and the outer core of the electromagnet coil 4 inserted into the slot of the outer core 1 (1) It is comprised so that the distance of the slot inner part may remain the same.

An object of the present invention for solving the problems of the conventional circular cross-section linear induction pump as described above, the gap between the outer core and the inner core is kept constant in the circumference to prevent the leakage of magnetic flux along the circumferential direction Fabrication and assembly of external cores that lead to a uniform radial magnetic field circumferentially toward the inner core to increase the driving efficiency of the pump, to ensure a constant flow of liquid metal fluid in a narrow flow path, and to have the same curvature as that of the coil bundle. The purpose is to provide an annular cross-section linear induction pump that can maximize its function.

1 is a cross-sectional view of a conventional circular cross-section linear induction electron pump,

2 is a cross-sectional view of a ring cross-section linear induction electron pump of the present invention,

3 is the magnetic force line distribution for the external core arrangement of the octagonal shape,

4 is a magnetic force line distribution for the outer core arrangement of the circular shape,

5 is an external core structure diagram of FIG. 2 according to the present invention;

<Description of the code | symbol about the principal part of drawing>

The same applies in FIGS. 1, 2 and 5

(1): External core (Core) (2): Internal core (Core)

(3): Duct (4): Coil

(5): spacer (6): liquid metal

(7): External core slot (Slot) for coil insertion

(8): Square support for fixing external core

(9): side support plate (10): coil support ring

(11): ferromagnetic plates

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The circular cross-section linear induction pump having a uniform intercore gap has a basic configuration as shown in FIG. 2, and is designed to solve the problem of the conventional circular cross-section linear induction pump as shown in FIG. And a duct 3 composed of two non-magnetic SUS pipes having different diameters coaxially disposed between the inner cores 2 and formed to maintain a constant flow path width by the spacer 5. Between the slots 7 of the radially arranged outer cores 1, the electromagnet coils 4 are wound on the coil support rings 10 and inserted at regular intervals so that the liquid metal 6 can be forced under one direction to flow. It is configured to.

According to the present invention having the configuration as described above, the outer core 1 has a circular arc shape that matches the radius of curvature of the duct below and above the outer core 1, as shown in FIG. 5, on both sides of the outer core 1. The ferromagnetic plates are laminated so that the width gradually decreases gradually, and then the cut surfaces are coated with a ceramic inorganic adhesive to maintain electrical insulation at a high temperature and the binding of the formed cores. Then, the end faces are assembled and finished by the square support (8). The ears are configured to be cut into a fan-like shape, and eight are made to be arranged radially in the circumferential direction, so as to be combined with the side support disk 9 to form a pump structure.

The outer core 1 manufactured in the same way as the curvature of the duct coincides with the curvature of the electromagnet coil 4 having the same curvature as the duct, and the outer core and the outer core of the electromagnet coil 4 inserted into the slot of the outer core 1. (1) It is comprised so that the distance of the slot inner part may remain the same.

When explaining the effect of the present invention configured as described above in detail, the electron pump of the present invention using the outer core made to have a uniform inter-gap gap, the gap between the outer and inner core along the circumferential direction is generated, The radial magnetic flux is constant in the circumferential direction, and these constant magnetic fluxes are led to the inner core arranged radially, and the area of the ferromagnetic material exists over a certain thickness in all parts of the duct circumference to minimize the leakage of magnetic flux. Thus, it plays a role of maximizing pumping efficiency.

The outer core, which has the same curvature of the duct and the electromagnet coil, has the shape of the slot and the end face of the arc of the same curvature as the coil, so that the number of turns of the electromagnet coil can be increased compared to the conventional external core manufacturing method. Even pumps of size have the effect of further raising the pump driving force proportional to the square of the number of turns.

Although the present invention has been described in accordance with the above embodiments, the present invention can be modified in various ways without departing from the core of the number of external core bundles, geometric sizes, materials used, etc. according to the use conditions.

Claims (2)

The electrically conductive molten liquid metal flows along a narrow channel in the form of a ring under the electromagnetic force represented by the product of a time-varying magnetic field and an induced current induced in a direction perpendicular to the outer core (1), inner core (2), duct (3) and coil. (4) In the cross-sectional linear induction electron pump composed of a spacer (5), a square support (8), a side support plate (9), a coil support ring (10), a ferromagnetic plate (11), The outer core 1 is arranged to maintain a constant gap between the outer core 1 and the inner core 2 along the circumference of the duct 3 and the ferromagnetic body 11 is laminated along the circumference of the duct 3. A circular cross-section linear induction pump having a uniform inter-gap gap characterized in that the magnetic flux is minimized and a uniform radial magnetic field is led into the inner core 2 along the circumferential direction. 2. An outer core (1) according to claim 1, wherein the outer core (1) having the same curvature as the duct (3) and the electromagnetic coil (4) is formed between the upper surface of the inner core (7) and the outer surface of the electromagnetic coil (4). Circular cross-section linear induction electron pump having a uniform inter-gap gap, characterized in that the distance is uniformly assembled to increase the number of coil windings for the pump of the same size to maximize the pump driving force of the reduced size.