Background
At present, because of good electromagnetic performance, superconducting materials are widely applied to devices such as generators, motors, magnetic suspension and the like. The second generation high temperature superconducting ReBCO (a superconducting material, chemical formula (Re) Ba2Cu3O7) material form can be roughly divided into three types: bulk, tape, and film. Stacking and fixing a plurality of superconducting tapes with the same shape and size together to form a similar block material similar to the block material, wherein when the temperature is reduced, the capture magnetic field is not saturated and is increased all the time; in addition, the metal layers of copper, silver, hastelloy and the like in the stacked strip also greatly enhance the mechanical strength of the stacked strip.
After the superconducting strips are stacked into the similar blocks, excitation is needed, and the stacked strips can capture a magnetic field to become the superconducting magnet. The excitation mode of the stacked strips is the same as that of the blocks, and the stacked strips are mainly divided into field cooling, zero field cooling and pulse excitation. The field cooling needs to cool the stacked strips to the working temperature in a constant magnetic field environment, and then the permanent magnet generating the magnetic field is removed or the external magnetic field is cancelled; and zero field cooling is to apply an external magnetic field after cooling the stacked strips to the working temperature, maintain the external magnetic field for a period of time and then remove the external magnetic field. The pulse excitation is to apply a pulse magnetic field to the stacked strips to excite after the superconductor is cooled to the working temperature, and the peak value and the pulse width of the pulse need to be adjusted according to actual needs. In practical application, pulse excitation is the most convenient and practical of all excitation modes because the generation of stable strong magnetic fields required by field cooling and zero field cooling excitation is very difficult.
Because there are many excitation methods, and the excitation magnet may be the permanent magnet, also may be the electromagnet, traditional excitation device can't be compatible many excitation methods, also has the difficulty in the switch of excitation magnet, in addition, the size of the stacking strip is different, also brings the challenge to the design of excitation device.
Therefore, those skilled in the art have devoted themselves to develop a stacked strip excitation device that can simultaneously meet the application requirements of multiple excitation modes, and can conveniently switch the excitation magnets, and can also be compatible with stacked strips of different sizes.
Disclosure of Invention
In view of the above-mentioned defects in the prior art, the technical problem to be solved by the present invention is to provide an excitation device that has a reasonable structure, is easy to operate, does not require complicated assembly and disassembly, is adjustable in air gap length and accurate in positioning, is compatible with permanent magnets and electromagnets, and is compatible with stacked strips of different sizes.
In order to achieve the aim, the invention provides a high-temperature superconducting stacked strip excitation device which comprises an excitation magnet base, a sliding block, an excitation magnet sliding sheet and a sample sliding sheet, wherein the excitation magnet base is connected with the base through welding; the sliding block is used for bearing the sample slide sheet and can slide on the base; the sliding block and the base can be fixed through screws; the excitation magnet sliding sheet is used for bearing an excitation magnet and is fixed on the excitation magnet base; the sample slide is used for fixing the excited stacked strips.
Further, the base is L-shaped and is divided into a long side and a short side.
Furthermore, a positioning transverse groove is formed in the long edge of the base along the vertical direction; the short edge is provided with a positioning sliding groove along the horizontal direction.
Furthermore, the number of the positioning transverse grooves is greater than 1, and the number of the positioning sliding grooves is greater than 1.
Furthermore, a graduated scale is arranged on the top surface of the long edge of the base, and the graduated scale corresponds to the moving position of the sliding block.
Furthermore, the excitation magnet base is concave, two sides of the excitation magnet base are respectively provided with a clamping groove, and the size of each clamping groove corresponds to that of the excitation magnet slip sheet.
Furthermore, the sliding block is divided into an upper half area and a lower half area in the vertical direction, and the upper half area and the lower half area are separated by a partition plate.
Furthermore, two sides of the lower half area of the sliding block are respectively provided with a clamping groove, and the size of each clamping groove corresponds to that of the sample sliding sheet; the bottom of the sliding block is provided with a plurality of hemispherical positioning wedges, and the size of each positioning wedge corresponds to the positioning sliding groove on the short edge of the base; and two sides of the upper half area of the sliding block are respectively provided with a plurality of screw positioning holes, and the positions of the screw positioning holes correspond to the positioning transverse grooves on the long edge of the base.
Further, the sample slide is characterized in that the sample slide is provided with dense transverse holes, and the transverse holes are different in size and used for fixing stacked strips with different sizes.
Further, the excitation magnet sliding sheet is fixed with the excitation magnet through low-temperature glue, and can bear a permanent magnet or an electromagnet.
The invention has the advantages that:
(1) the material can work in a liquid nitrogen environment, and the temperature is lower than the critical temperature of the ReBCO superconducting material;
(2) all excitation modes of the stacked strips can be compatible, including field cooling, zero field cooling and pulse excitation;
(3) the length of the air gap can be adjusted in the excitation process, and the sliding block cannot laterally displace;
(4) the excitation magnet is flexible to select, and a permanent magnet and an electromagnet can be selected;
(5) it is applicable to stacked strips of any size smaller than the sample slide;
(6) the slide block can be mechanically fixed, and is suitable for the situation that large electromagnetic force exists between the exciting magnet and the sample.
The conception, the specific structure and the technical effects of the present invention will be further described with reference to the accompanying drawings to fully understand the objects, the features and the effects of the present invention.
Detailed Description
The technical contents of the preferred embodiments of the present invention will be more clearly and easily understood by referring to the drawings attached to the specification. The present invention may be embodied in many different forms of embodiments and the scope of the invention is not limited to the embodiments set forth herein.
In the drawings, structurally identical elements are represented by like reference numerals, and structurally or functionally similar elements are represented by like reference numerals throughout the several views. The size and thickness of each component shown in the drawings are arbitrarily illustrated, and the present invention is not limited to the size and thickness of each component. The thickness of the components may be exaggerated where appropriate in the figures to improve clarity.
As shown in fig. 1 and 2, a high-temperature superconducting stacked strip excitation device is provided. In the embodiment, the device comprises five modules, namely an excitation magnet base 1, a base 2, a slide block 3, an excitation magnet slide sheet 4 and a sample slide sheet 5, wherein the excitation magnet base 1 is connected with the base 2 through welding; the slide block 3 is used for bearing a sample slide sheet 5 and can slide on the base 2; the sliding block 3 and the base 2 can be fixed through screws; the excitation magnet sliding sheet 4 is used for bearing an excitation magnet 81 and is fixed on the excitation magnet base 1; the sample slide 5 is used to hold the stack of strips 6 that are excited.
The base 2 is L-shaped and is divided into a long side and a short side. The long edge is vertical to the direction, and is provided with a positioning transverse groove 10; the short edge is provided with a positioning chute 9 along the horizontal direction. In the present embodiment, the number of the positioning lateral grooves is 2, and the number of the positioning slide grooves is 2. The top surface of the long edge of the base 2 is provided with a graduated scale 7, and the graduation of the graduated scale 7 corresponds to the moving position of the slide block 3.
The excitation magnet base 1 is concave, two sides of the excitation magnet base are respectively provided with a clamping groove 11, and the size of each clamping groove corresponds to that of the excitation magnet sliding sheet 4.
As shown in fig. 3, a top view of the field magnet base 1 and the slider 3 is shown. Two sides of the excitation magnet base 1 are respectively provided with a clamping groove 11 for fixing the excitation magnet sliding sheet 4; on both sides of the slide 3, there are also two slots 12 for holding the sample slide 5.
As shown in fig. 4, which is a front view of the slider 3, the slider 3 is vertically divided into an upper half 13 and a lower half 14, which are separated by a partition. The bottom of the sliding block 3 is provided with two hemispherical positioning wedges 15 for mounting the sliding block 3 on the positioning sliding groove 9 of the excitation magnet base 1. Therefore, the air gap length can be adjusted during excitation, and the slider 3 is not displaced laterally.
As shown in fig. 5, the excitation magnet sliding piece 4 is fixed to the excitation magnet 81 or 82 by low temperature glue, and can carry the electromagnet 81 or the permanent magnet 82.
The working flow of a preferred embodiment of the invention in three different working modes of field cooling, zero field cooling and pulse excitation is described below with reference to the accompanying drawings:
(1) field cooling
When field cold excitation is performed on the stacked strip, a permanent magnet slide sheet shown in fig. 5 is used. And (3) sliding the slide block 3 to a position where the stacked strip 6 is close to the permanent magnet, tightly fixing the slide block 3 between a screw hole and a positioning transverse groove 10 of the base 2 through a screw nut, and then immersing the whole device into liquid nitrogen, wherein the liquid level of the liquid nitrogen is beyond the stacked strip sample. After the liquid nitrogen boils stably, the fastened screw nut is detached, the top transverse handle of the upper half area 13 of the sliding block is held, the sliding block 3 slides along the base positioning sliding groove 9, the sliding block 3 is far away from the permanent magnet 82, when the air gap length reaches more than 15cm, the magnetic field of the permanent magnet 82 is basically attenuated to zero at the position of the stacked strip 6, and field cooling excitation is completed. The magnetic field trapped in the stacked strip 6 includes two parts, one is a magnetic field in which intrinsic defects in the superconducting strip are occluded, and the other is a magnetic field generated by eddy currents generated during the process of being away from the permanent magnet 82.
(2) Zero field cooling
The zero field cold excitation process is substantially the same as field cooling, except that the slide 3 is fixed away from the permanent magnet 82 when the device is immersed in liquid nitrogen. After the liquid nitrogen boils stably, the sliding block 3 is gradually close to the permanent magnet 82, and after the sliding block 3 is kept for a period of time, the sliding block 3 is gradually far away from the permanent magnet 82. In the stacked strip 6 after zero field cold excitation, the main component of the generated magnetic field is the magnetic field generated by the induced eddy current.
(3) Pulse excitation
Pulsed excitation uses an electromagnet 81 as shown in fig. 5. The air gap length need not change during excitation. The slider is placed and fixed close to the electromagnet 81 and the electromagnet 81 is connected to the pulse magnetizing machine. The device is immersed in liquid nitrogen, after the liquid nitrogen boils stably, pulse current is charged into the electromagnet 81 through a pulse machine, the electromagnet 81 generates a pulse magnetic field, and pulse excitation is carried out on the stacked strips 6.
The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.