JPS593542Y2 - boiling cooled electromagnet - Google Patents

Description

[Detailed description of the invention] This invention relates to an electromagnet used as a moving object field in a synchronous linear motor, and in particular to a boiling-cooled electromagnet that has been improved to efficiently cool all of the wires that make up the electromagnet's coil. Regarding.

Patent application No. 52-109441 previously proposed by the inventors of the present application
The boiling cooling type electromagnet according to the above issue is surrounded by an annular boiling cooling tank body so as to form a cooling medium flow path between the outer surface of the annular coil and the inner wall surface of the cooling tank body, and an iron core is fitted into this. It consists of
Heat generated in the coil is removed by latent heat of vaporization when the liquefied cooling medium vaporizes.

For this reason, bubbles rise from the bottom of the cooling tank upwards, creating a gas region in the upper space. If the strands at the top of the coil are exposed in this gas region, the cooling effect decreases, and the cooling of the coil as a whole decreases. It was found that there was a structural problem that reduced efficiency.

For this reason, we adopted a structure that communicates the upper and lower parts of the annular cooling tank to prevent the concentration of air bubbles, but a gas region tends to form inside the upper cooling tank, and a part of the coil is exposed to the gas region. The problem of different cooling effects could not be completely resolved.

The purpose of this invention is to use a structure that quickly eliminates air bubbles generated by the vaporization of the liquefied cooling medium from the cooling tank, and a structure that prevents the formation of bubble regions formed by the concentration of air bubbles within the cooling tank. An object of the present invention is to provide an improved boiling-cooled electromagnet that can maintain stable cooling efficiency by constantly immersing the entire body in a liquefied cooling medium.

That is, this invention is a boiling cooling system in which an annular coil is surrounded by an annular boiling cooling tank body and an iron core is fitted therein so that a cooling medium flow path is formed between the outer surface of the annular coil and the inner wall surface of the cooling tank body. In the type electromagnet, one or more air bubble collecting passages are provided which pass through the iron core into which the annular cooling tank body housing the annular coil is inserted and communicate with the cooling tank body parts located at the upper and lower parts by opening upward. It is characterized by being provided in the cooling tank body at predetermined intervals.

Preferred embodiments of this invention will be described below with reference to the drawings.

Figure 1 shows a cross section of one embodiment of this invention.
FIG. 2 shows a cross-sectional perspective view taken along line AA' in FIG. 1.

Referring to FIGS. 1 and 2, annular coils 1 and 1' are housed in cooling tank bodies 2 and 2', each of which is fitted into an iron core 3 having a partially open cross-sectional shape. A parallel magnetic flux is generated between the extreme parts 9.

Each of the annular coils 1, 1' is formed by overlappingly winding strands of wire having a flat cross-sectional shape, and the outer peripheral surface of the unwound wire is appropriately electrically insulated.

In addition, the long side surfaces of the strand cross section are overlapped with each other when wound into a coil, and both short side surfaces are always exposed on both sides for each winding, so that when stored in the cooling tank body 2, the cooling medium Both short sides of the wire will come into contact.

In the cooling tank body 2, an upper tank part 4 and a lower tank part 5 are connected by a communication hole 6 passing through a plurality of iron cores 3, and a cooling medium flow path between the upper tank part 4 and the lower tank part 5 is formed. Furthermore, a communication hole 7 following the communication hole 6 is provided in the upper part of the upper tank part 4 and penetrates through the iron core 3. The collection aisle is now in full form.

Also connected to the cooling tank body 2 are a conduit 10 for supplying the liquefied selling medium and a conduit 11 for collecting the vaporized cooling medium and sending it to a condensing device (not shown).

In this way, the lower tank part 5 and the upper tank part 4 of the cooling tank body 2 are connected to the communication hole 6.
Since the upper tank part 4 is connected to the conduit 11 through the communication hole 7, the bubbles of the cooling medium vaporized in the lower tank part 5 reach the upper tank part 4 through the communication hole 6, where they are connected to the upper tank part 4. Tank part 4
The generated air bubbles are returned to the condensing device from the conduit 11 through the communication hole 7, so that a gas region due to concentration of air bubbles does not occur in the cooling tank body 2, and the annular coil 1 is always filled with liquefied cooling medium. This allows stable cooling efficiency to be maintained.

Note that, since the amount of gas of the cooling medium passing through the communication hole 7 is approximately twice that of the communication hole 6, it is desirable to make the communication hole 7 sufficiently large to prevent the generation of a gas region in the upper tank portion 4, as shown in FIG. 1 shows another embodiment of this invention, in which the upper tank walls of the upper and lower tank parts 4 and 5 are connected in order to guide the upper tank part 4 and the lower tank part 5 of the cooling tank body 2 to the communication hole 6.7. They are provided obliquely toward the communication holes 6 and 7, respectively.

As a result, the generated air bubbles are quickly removed from the inside of the cooling tank body 2 through the communication holes 6 and 7 without staying in the upper parts of the upper and lower tank parts 4 and 5.

Next, in the above-mentioned embodiment, it will be explained at what intervals the bubble collecting passages made up of the communicating holes 6 and 7 should be provided.

First, the inventors of the present invention used the experimental apparatus schematically shown in Figures 4 and 5 to find out that when bubbles generated from the cooling medium gather to form a gas region, and the surface of the heating element is covered by this gas region. The heat flux of burnout heat flux q (Kcal/hr
m2) was obtained as shown in the graph shown in FIG.

Referring to FIGS. 4 and 5, the experimental apparatus includes a heating element 13 having a built-in electric heating coil placed inside a tank 12, a baffle plate 14 placed above the heating element 13,
The area partitioned by is further partitioned by spacers 15 on both sides of the heating element 13, so that the length i can be changed by moving the spacers 15.

Further, as is clear from FIG. 5, there are spacers 1 on both sides of the heating element 13 that partition the heating element 13 with a gap ΔR.
6 is arranged so that the distance ΔR can be changed by moving the spacer 16.

Further, a condenser 17 is provided in the upper part of the tank 12, and cooling water is passed through the condenser 17 to absorb heat from the cooling medium put in the tank 12.

As the cooling medium, fluorinated oil with a molecular weight of about 400 (hereinafter referred to as Refrigerant II) and fluorinated oil with a molecular weight of approximately 600 (hereinafter referred to as Refrigerant II) were used.

First, the distance △R between the heating element 13 and the spacer 16 is determined by △R
= 5 mm, and when the length l was changed by moving the spacer 15, the refrigerant engineer found that the burnout heat flux changed as shown by the straight line 18.

It was also found that the burnout heat flux of refrigerant II changes as shown by dotted line 19.

Also, when △R=lQmm and refrigerant ■ is used, the straight line is 20, △R
When refrigerant (2) was used at -20 mm, the results shown in each of the straight lines 21 were obtained.

Therefore, when considering the graph in Figure 6, for example, the straight line 18
For example, it is possible to know the burnout heat flux q that is the critical value at which the medium I in the region partitioned by the length l that gives the position of the spacer 15 starts to form a gas region.

Assuming now that the amount of heat per unit area generated by the annular coil 1 in the embodiment shown in FIG. 1 is 8×104 (KCal/hr
m2) From straight line 18 in Figure 6, l=
At 50 cm, the burnout phenomenon begins to form a gas region.

Therefore, the communication holes 6, which should be provided in the embodiment of FIG.
7 is determined to be every 50 cm.

In an actual device, a safety factor is taken into consideration, so the interval between the communicating holes 6 and 7 is determined to be 50 cm or less depending on the safety factor, for example, 30 cm with the safety factor S=1.2.

As explained above, the boiling cooling type electromagnet device of this invention has one or more air bubble collecting passages in the lower part of the cooling tank body, the interval of which is determined based on the burnout heat flux critical value depending on the cooling medium used. By providing a pipe that passes through the iron core from the upper tank to the upper tank, and then to the conduit that collects the gas, it is possible to quickly extract air bubbles from the vaporization of the liquefied cooling medium without creating a gas region inside the cooling tank. Therefore, the annular coil housed in the cooling tank body can be immersed in the liquefied cooling medium at all times, making it possible to maintain a stable cooling effect without causing any imbalance in the cooling effect on the annular coil. It is something that has become familiar.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of this invention, FIG. 2 is a cross-sectional perspective view of FIG. 1 taken along line AA' force direction, and FIG.
A sectional view showing another embodiment of this invention, Fig. 4.5 is a schematic illustration showing the experimental apparatus used to obtain the critical value of burnout heat flux, and Fig. 6 shows the experiment of Fig. 4-5. FIG. 3 is a graph showing the relationship between the length l obtained by the device and the burnout heat flux. 1.1'... circular coil, 2,2'...
・Cooling tank body, 3... Iron core, 4... Upper tank part, 5... Lower tank part, 6, 7... Communication hole, 8... ... air gap, 9 ... magnetic pole part, 10.
11... Conduit, 12... Tank, 13
... Heating element, 14 ... Baffle plate, 15.
16...Spacer, 17...Condenser.

Claims (1)

[Claims for Utility Model Registration] An annular coil is surrounded by an annular boiling cooling tank body and an iron core is inserted therein so that a cooling medium flow path is formed between the outer surface of the annular coil and the inner wall surface of the cooling tank body. In a boiling-cooled electromagnet, one or more air bubbles pass through an iron core inserted into an annular cooling tank body housing an annular coil and open upwardly to communicate with the cooling tank bodies located at the upper and lower parts. A boiling cooling type electromagnet characterized in that a cooling tank body is provided with collecting passages at predetermined intervals.