JP2939375B2 - Electromagnetic pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an annular linear type three-phase induction electromagnetic pump, and more particularly to a high-temperature environment such as a coolant circulation pump for a liquid metal-cooled reactor using liquid metal as a coolant. It relates to the electromagnetic pump used.

[0002]

2. Description of the Related Art A high temperature environment such as a liquid sodium coolant circulating pump of a liquid sodium cooled reactor using liquid metal as a coolant (sodium is often used as a liquid metal). The large-capacity three-phase induction electromagnetic pump used below is roughly classified into a flat linear type and an annular linear type in terms of structure. In the present invention, the annular linear type is targeted. This annular linear electromagnetic pump has an annular liner induction
p). High reliability and safety of duct structure make it suitable for large capacity reactor coolant pump. FIG. 5 is a perspective sectional view showing the basic structure of an annular linear electromagnetic pump common to the present invention and the conventional example. The structural features include the following. (1) The duct forms an annulus flow path 3 with a concentric double pipe composed of an outer duct 1 and an inner duct 2 made of stainless steel. This duct has an annular shape and is excellent in strength, so that the reliability is high. (2) The stator 4 is provided outside the outer duct 1, and includes a plurality of radially arranged laminated stator cores 5 and a ring-shaped heat-resistant coil 6. (3) Inside the inner duct 2, a laminated inner core 7 for forming a magnetic circuit is accommodated. (4) The liquid sodium flows through the annulus flow path 3 as shown by the arrow. The heat-resistant coils 6 of the three-phase electromagnetic pump are arranged in each phase group along the flow direction. That is, each of the ring-shaped heat-resistant coils 6 is a three-phase alternating current U-phase, V-phase.
The heat-resistant coils 6 of the U-phase, V-phase, and W-phase are connected in series. Furthermore, the whole is covered with a casing 8 between the outer duct 1 and hermetically sealed. When a three-phase alternating current is applied to each phase of the heat-resistant coil 6, a moving magnetic field is generated, and an interaction with the induced current generates a thrust in the liquid sodium. As a basic form of the annular linear electromagnetic pump, a radial laminated stator core 5 and a ring-shaped heat-resistant coil 6 are provided outside the outer duct 1, and inside the inner duct 2. A single stator (single stator) type electromagnetic pump in which a laminated internal core 7 for forming a magnetic circuit is housed, and a radial laminated stator core 5 and a ring-shaped heat-resistant outside the outer duct 1. At the same time as the coil 6 is provided, there is a double stator (double stator) type electromagnetic pump in which a radial laminated stator core and a ring-shaped heat-resistant coil are also provided inside the inner duct 2.

Since the present invention is common to both types of electromagnetic pumps, a single stator type electromagnetic pump will be described below. The structure of the heat-resistant coil 6 of the conventional electromagnetic pump will be described with reference to FIGS. As shown in the perspective view of the heat-resistant coil in FIG. 6, the required number of coil conductors 9 are wound in a ring shape, and the outside of the coil conductor 9 is wound with a coil main insulating material 10. In the case of a three-phase induction electromagnetic pump, three coils are used. The coil lead terminal 11 is drawn out from the place. FIG. 7 is a cross-sectional view of the heat-resistant coil, showing a cross section of the coil conductor 9 and the coil main insulating material 10. The coil conductor 9 is formed by winding a required number of wires in a ring shape, but the cross section of each wire is not shown here. FIG. 8 is a perspective sectional view showing a part of the ring-shaped heat-resistant coil 6. In the heat-resistant coil 6 of an ordinary electromagnetic pump, copper or a copper alloy having excellent heat resistance is used for the conductor. In addition, the electromagnetic pump used for the liquid sodium coolant circulation pump of a liquid sodium cooled reactor cannot be used with conventional organic insulating materials because it is operated in a high-temperature environment. Is used. The basic configuration is such that a mica tape 12 having good insulating properties is wrapped around the outside of the coil conductor 9, and a ceramic tape 13 is further wrapped around the mica tape 12, and an adhesive is applied and fixed. The mica tape 12 has good heat resistance, as shown in the perspective view of FIG. 9A, in which the mica 122 is adhered to an alumina or glass cloth backing material 121 with an adhesive 123. . The shape of the ceramic tape 13 is shown in the perspective view of FIG.

[0004]

The coefficient of thermal expansion of copper or copper alloy which is usually used as the coil conductor 9 is 13-15.
Is about × 10 ^-6 [1 / degree, and the thermal expansion coefficient of the ceramic material used as the insulating material is approximately 3 to 5 × 10 ^-6. For this reason, in a relatively small electromagnetic pump, no problem occurs because the diameter of the ring-shaped heat-resistant coil 6 is small, but in the case of a large electromagnetic pump, the heat-resistant coil 6 becomes large and the difference in the coefficient of thermal expansion is large. If the difference in thermal expansion cannot be completely absorbed, there is a problem that a crack is generated in the coil main insulating material 10 and the insulating property is reduced.

An object of the present invention is to provide an insulating material having elasticity following the thermal expansion of a coil conductor, or to provide insulation by providing a gap between the coil conductor and a main insulating material, so that the insulating material can be used in a high-temperature environment. It is an object of the present invention to provide an electromagnetic pump in which the insulating material is not cracked even if the coil conductor expands due to the expansion of the coil conductor, and the insulating property does not decrease.

[0006]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
The present invention relates to an annular linear electromagnetic pump having a radial stator core and a ring-shaped heat-resistant coil in a casing, wherein the heat-resistant coil has a peeling mica tape using a ceramic cloth as a backing material outside a coil conductor. Is wound without using an adhesive, and on top of this main insulation
And a bag-knitted protective insulating ceramic fiber which has been subjected
Configuration . Alternatively, the coil conductor of the heat-resistant coil
After surrounded by the main insulation of the ceramic by arranging the low melting point glass tube in a ring outside the circumference, the coil conductors between said calcined from melt reduction of the low melting point glass tube and the ring outer periphery of the coil conductor and the main insulating material To form a space that allows for escape due to the thermal expansion of
Configuration .

[0007]

When the electromagnetic pump is placed in a high temperature environment, the coil conductor expands. Mica stripped of insulation due to this, slippage occurs due to cleavage of it holds, insulation resistance is not cracks caused to decrease. The backing material of mica tape is
Since it is an inorganic ceramic, it does not melt or decompose
Keep mica stable. In addition, the flexible insulation of the knitted bag made of ceramic fiber applied to the outside of the main insulation absorbs the difference in the expansion of the mica tape.
And protect against trauma . The elongation due to thermal expansion of the coil conductors, the gap between the coil main insulating material formed by melt reduction of the low melting point glass tube placed in a ring outside the circumference of the coil conductor to move freely, the coil main insulation without giving stress, thus Rukoto is Do <br/> physician crack the coil main insulation.

[0008]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective sectional view showing a part of a heat-resistant coil. A heat-resistant coil 20 is an annular linear electromagnetic type used in a high-temperature environment such as a liquid sodium coolant circulation pump of a liquid sodium-cooled reactor. In the ring-shaped stator coil of the pump, no adhesive is used for the main insulation on the outer side of the coil conductor 9 in which the coil wire is wound in a ring shape. It is constituted by covering with a protective insulation 21 formed in a bag. FIG. 2 is a perspective view showing a part of the insulating material. FIG. 2A is a perspective view showing a part of the peeling mica tape 21. The peeling mica 212 is attached to a backing material 211 made of glass cloth or ceramic cloth. The adhesive strength at the boundary surface between the backing material 211 and the mica 212 is not expected. As shown in FIG. 1, the peeled mica tape 21 is wrapped around the coil wire 9 whose winding has been completed, and furthermore, in order to fix the peeled mica tape 21, FIG.
(B) is covered with a protective insulation 22 of a bag knitting shown in the perspective view and sewn on the side and the like. The protective insulation 22 is made of a highly heat-resistant ceramic fiber such as an alumina fiber in a bag-knitted form, and
The peeling mica tape 21 can be firmly fixed even if the coil dimensions change due to the thermal expansion. Next, the operation of the configuration of the above embodiment will be described. When the coil conductor 9 is exposed to a high temperature of about 600 ° C., the coil conductor 9 becomes large due to thermal expansion of the coil conductor 9. In this case, the peeling of the mica tape 20 causes a slip on the cleaved surface of the mica 212, but the mica pieces overlap each other, so that there is no problem in the insulating function. Also, peel mica tape
Since the periphery of the cover 20 is covered with the protective insulation 22 made of a free-stretch bag, no drop due to a thermal load or a vibration load occurs, and a stable insulation function can be maintained.

FIGS. 3 and 4 show another embodiment of the present invention. As shown in the perspective view of the heat-resistant coil in FIG. 3, the heat-resistant coil 30 of the electromagnetic pump is formed by winding a required number of coil conductors 9 in a ring shape, and an annular low-melting-point glass tube 31 is arranged on the outside thereof. The coil main insulating material 10 is wound. In the case of a three-phase induction electromagnetic pump, the coil lead terminals 11 are drawn from three places. FIG. 4 is a cross-sectional view of the heat-resistant coil, and FIG. 4A shows a state after the heat-resistant coil is assembled. A low-melting glass tube 31 is provided in close contact with the outside of the coil conductor 9, and is covered with the coil main insulating material 10. I have. Since the heat-resistant coil 30 uses a ceramic material as the coil main insulating material 10,
After assembling the heat-resistant coil 30, it is placed in a high-temperature firing furnace and the ceramic insulating material is fired at an appropriate temperature. During firing of the insulating material, the entire heat-resistant coil 30 is housed in a mold (not shown) and placed in a firing furnace. Therefore, as shown in FIG. 4 (B), the coil conductor 9 expands outward due to thermal expansion, but the low melting point glass tube 31 disposed outside the coil conductor 9 is softened and melted and crushed to form an inner space. 32a is formed. Therefore, firing is performed without giving excessive stress to the coil main insulating material 10 having a small coefficient of thermal expansion. When the temperature is lowered after the completion of the firing of the insulating material, the state shown in FIG. At this time, the coil conductor 9 also returns to the normal temperature state, but the low melting point glass tube 31 remains crushed in the fired coil main insulating material 10, so that the coil conductor 9 is located between the coil conductor 9 and the coil conductor 9. An outer space 32b is formed. Next, the heat-resistant coil 30 constructed as shown in FIG.
Is applied to an electromagnetic pump, when the coil conductor 9 becomes high temperature, the coil conductor 9 expands due to thermal expansion. However, the expansion part expands and contracts freely in the outer gap 32b, and the coil main body having a small thermal expansion coefficient The coil main insulating material 10 does not directly interfere with the insulating material 10, so that cracks and the like do not occur in the coil main insulating material 10 and the insulating property does not decrease.

[0010]

As described above, according to the present invention, in a ring-shaped coil of a large-capacity electromagnetic pump used in a high-temperature environment such as a liquid sodium coolant circulation pump, thermal expansion of a coil conductor at a high temperature state The amount of elongation and shrinkage during cooling due to the difference from the insulating material coated on the outer periphery can prevent the insulating material from being damaged, and the insulation does not decrease, so the safety of the electromagnetic pump and the nuclear power plant employing this, This has the effect of improving reliability.

[Brief description of the drawings]

FIG. 1 is a perspective sectional view showing a part of a heat-resistant coil according to one embodiment of the present invention.

FIG. 2 is a perspective view showing a part of an insulating material according to one embodiment of the present invention (FIG. 2 (A) is a perspective view of a peeling mica tape, and FIG. 2 (B) is a perspective view of a bag-knitting protective insulation).

FIG. 3 is a perspective view of a heat-resistant coil according to another embodiment of the present invention.

FIG. 4 is a cross-sectional view of a heat-resistant coil according to another embodiment of the present invention (FIG. 4 (A) is a cross-sectional view of an assembled heat-resistant coil, FIG. 4 (B) is a cross-sectional view of a heat-resistant coil being fired, FIG. C) is a cross-sectional view of the heat-resistant coil after firing.

FIG. 5 is a perspective sectional view of an annular linear electromagnetic pump.

FIG. 6 is a perspective view of a conventional heat-resistant coil.

FIG. 7 is a cross-sectional view of a conventional heat-resistant coil.

FIG. 8 is a perspective sectional view showing a part of a conventional heat-resistant coil.

FIG. 9 is a perspective view showing a part of a conventional insulating material (FIG. 9 (A) is a perspective view of a mica tape, and FIG. 9 (B) is a perspective view of a ceramic tape).

[Description of Signs] 1 ... Outer duct, 2 ... Inner duct, 3 ... Annulus flow path, 4 ... Stator, 5 ... Laminated stator core, 7 ... Laminated inner core, 8 ... Casing, 9 ... Coil conductor, 10 ... Coil main insulation, 20, 30 ... heat-resistant coil, 21 ... peeling mica tape,
22: protective insulation, 31: low melting point glass tube, 32a: inner space,
32b: Outside gap.

Claims (2)

(57) [Claims] 1. An annular linear electromagnetic pump having a radial stator core and a ring-shaped heat-resistant coil in a casing, wherein the heat-resistant coil has a peeling mica tape having a ceramic cloth as a backing material outside a coil conductor. having a main insulating wound without using an adhesive, and a bag-knitted protective insulating ceramic fibers were applied over this main insulation
Electromagnetic pump, characterized in that that. 2. A radial stator core and the ring-shaped heat coil in annular linear type electromagnetic pump having a casing, a low-melting glass tube in a ring <br/> outside periphery of the coil conductor of the heat coil After being arranged and surrounded by a ceramic-based main insulating material, it is fired to provide a clearance between the outer periphery of the coil conductor ring and the main insulating material due to the thermal reduction of the low-melting glass tube due to thermal expansion of the coil conductor. An electromagnetic pump comprising: