JPS5953091B2 - gas centrifuge - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas centrifuge, and more particularly to a gas centrifuge that can improve separation performance by creating an optimal temperature distribution within a rotating barrel.

In order to improve the separation performance of gas centrifuges, various improvements have been made to the flow of gas to be separated within the high-speed rotating barrel. There is a method of increasing the flow of water using thermal convection generated by creating a temperature difference between the top and bottom of the rotary cylinder to improve separation performance.

FIG. 1 shows the schematic structure of a scoop-type centrifugal separator in which a stationary tube for supplying and exhausting air is inserted into a rotating barrel.

A rotary drum 3 having upper and lower partition plates 1 and 2 fixed therein is supported by a magnetic bearing 4 and a pivot bearing 5, and is rotated at high speed by a rotary drive mechanism 7 within a vacuum container 6.

The gas G to be separated is ejected into the rotary shell from an air supply pipe 8 provided on the central axis of the rotary shell 3, and then circulates as shown by the arrow.
The light component gas and the heavy component gas are separated, and the light component gas L is extracted through the product scoop pipe 9, while the heavy component gas is extracted through the waist scoop pipe 10.

At that time, heat due to wind damage is generated between the upper partition plate 1 and the product scoop pipe 9, and between the lower partition plate 2 and the waist scoop pipe 10, and the temperature at both ends of the upper and lower partition plates 1, 2 and the rotating body 3 increases. to rise.

Further, the vicinity of the molecular pump 11 provided to maintain a high degree of vacuum inside the vacuum vessel 6 also generates heat due to windage damage with the rotary shell 3.

Furthermore, the lower end of the rotary drum 3 is also heated by the heat generated by the rotary drive mechanism 7.

Efforts have been made to suppress such temperature rise in the rotary drum 3 by passing cooling water, black body treatment, oil body treatment, etc., and to obtain a temperature distribution of the rotary drum that improves separation performance. However, the temperature distribution and the flow inside the rotating cylinder are as shown in Figure 2 a and l).

In other words, the temperature distribution becomes sagging in the middle, and as a result, the side wall heat convection of the flow inside the rotary cylinder is divided into upper and lower halves, and the effect of heat convection is halved, causing a decrease in separation performance.

Further, a large temperature gradient in the vicinity directly above the lower partition plate 2 also causes disturbance of the flow in the vicinity directly above the lower partition plate 2.

The present invention has been made to improve the above-mentioned drawbacks, and aims to improve separation performance by obtaining an optimal temperature distribution within the rotating barrel and by generating ideal heat convection within the rotating barrel. shall be.

In order to achieve this object, the present invention provides an electrode that is installed on the inner surface of the vacuum container facing the baffle plate mounting position of the rotary drum at an appropriate distance from the rotary drum, and that a negative DC voltage is applied to the electrode. It is characterized in that it is configured to apply an electric current.

That is, the present invention removes heat generated by a molecular pump or the like by an electrostatic cooling method, thereby obtaining a temperature distribution in the rotating body that can improve separation performance.

The electrostatic cooling method is (Kishi & Eda: Pr
actual development in the
Machining Process byUse
of the Elec
trostaticCooling, Int, J, MT
DR, Vol. 16 (1976)), this principle is as shown in FIG.

That is, in FIG. 3, 12 is a high-temperature object to be heat removed, a needle-shaped electrode 13 is brought close to this high-temperature object 12, a negative DC voltage is applied to the electrode 13 by a high voltage generator 14, and a positive DC voltage is applied to the electrode 13. The electrode 15 of is connected to ground 16.

By the above operation, an ion wind is generated from the electrode 13, and this ion wind removes heat from the high temperature object 12 and cools it.

The present inventors conducted an experiment to confirm the effectiveness of this cooling method, and the results will be explained.

FIG. 4 shows the configuration of the apparatus used in the experiment, in which a heater 18 is installed in a container 17 that can change the atmospheric pressure.
A built-in high temperature object 19 is placed, and a copper needle electrode 20 is brought close to it at a distance of 10 mm.

On the other hand, the high voltage generator 27 includes an AC power supply 26, a step-up transformer 23, a rectifier 21 for obtaining DC, a protective resistor 22, a voltmeter 24, and an ammeter 25, and has a needle-shaped cathode side. It was connected to the electrode 20, and the anode side was connected to the ground 16.

This device changes the atmospheric pressure and applied voltage inside the container 17,
The temperature change of the high temperature object 19 heated by the heater 18 was measured by the thermocouple 28.

The results are shown in FIG.

That is, the atmospheric pressure is 760 Torr and 2 × 10
'Torr showed the effect of electrostatic cooling in both cases.

For example, at point A, the voltage is 7200v, the current is 2 x 1O-5
A. Power consumption was 0, 144 W, and a cooling effect of 4 degrees was shown.

In addition, in an actual gas centrifuge, 10-2 to I
Since it is Q-4 Torr, 2 X 10'Torr
The fact that the cooling effect shown in the figure can be obtained even in the case of 1 means that the principle of electrostatic cooling can be applied to the cooling of the molecular pump section.

The upper limit voltage that can be used corresponds to the voltage at the boundary between the glow discharge region and the arc discharge region, and this voltage is 105
That's all.

When an arc discharge occurs, the object that is intended to be cooled is heated by thermionic radiation.

Next, an embodiment of a gas centrifuge according to the present invention provided with the above cooling means will be described with reference to FIGS. 6 and 7.

As shown in FIG. 6, a molecular pump 11 is provided on the inner surface of the vacuum container 6 so as to face the outer surface of the mounting position of the upper partition plate 1 of the rotating body 3. In this embodiment,
This molecular pump 11 is equipped with a needle electrode 2 as shown in FIG.
An annular conductor 29 having a plurality of inward protrusions 9a and having an annular portion covered with an insulating material 30 is attached, and the negative power terminal of the high voltage generator 27 is connected to the annular conductor 29 as a conductor. 31 and connect the ground 16 and the positive power terminal to the conductor 32.

The high voltage generator 27 consists of a transformer, a rectifier, etc., as shown in FIG.

Further, the insulating material 30 is made of ceramic or synthetic resin.

In this way, the needle-like electrode 29 is
When applying a negative high voltage (5X103~10”V) to a,
As explained above, an ion wind is generated between the rotating body 3 and the needle electrode 29a, and the part of the rotating body facing the molecular pump 11 can be cooled, so the temperature distribution inside the rotating body can be As shown by the solid line in Figure a, a temperature distribution without any sag can be achieved.

Note that the dotted line in FIG. 8a represents the temperature distribution in the conventional structure.

Furthermore, in the temperature distribution curve according to the present invention shown in FIG. 8a,
The temperature distribution at the position directly above the lower partition plate 2 is also linear, and this also applies to the inner surface of the vacuum vessel facing the part of the rotating body to which the lower partition plate 2 is attached, as shown in Figures 6 and 7. This figure shows the case where a needle-shaped electrode similar to that of
It can be changed by changing the number of needle electrodes, the distance from the rotating drum, and the level of applied voltage.

Since such a temperature distribution is obtained, thermal convection within the rotary cylinder has an ideal shape as shown in FIG. 8.

Therefore, the separation performance of the gas centrifuge can be improved.

Incidentally, if the needle electrodes are arranged in multiple stages as shown by the two-dot chain line in FIG. 6, it is possible to further improve the cooling effect.

As described above, the present invention incorporates an electrostatic cooling means into a gas centrifuge, and the temperature distribution within the rotary drum can be improved, so that the separation function can be improved.

Moreover, the power consumption for electrostatic cooling is small (1w
(below), operating costs can be reduced.

Additionally, if the distance between the rotary drum and the electrodes changes, the cooling effect will change (the smaller the distance, the greater the cooling effect), so a temperature detector is installed to detect the temperature near the location where the partition plate is attached to the rotary drum. By detecting the temperature change, it is also possible to know the positional deviation of the axis of the rotating body or the vibration amplitude.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-section showing the structure of a conventional scoop-type gas centrifuge, Figure 2 a and l) are diagrams showing the temperature distribution and heat convection that occur inside the rotating barrel of Figure 1, respectively, and Figure 3 is A diagram of the principle of the electrostatic cooling method, Fig. 4 is a configuration diagram of the experimental equipment for the electrostatic cooling method, Fig. 5 is a diagram showing the experimental results using the experimental equipment of Fig. 4, and Fig. 6 is a diagram showing the gas centrifugation according to the present invention. FIG. 7 is a plan view showing a detailed example of the electrodes used in the present invention, and FIGS. It is a figure showing the temperature distribution and thermal convection inside. 1...Top partition plate, 2...Bottom partition plate, 3
...Rotating cylinder, ...Vacuum container, 8...
...Air supply pipe, 9...Product scoop pipe,
10...West scoop tube, 11...
・Molecular pump, 27...High voltage generator, 29
. . . Annular conductor, 29a . . . Needle electrode, 30 . . . Insulating material.

Claims (1)

[Scope of Claims] 1. In a gas centrifuge in which a rotating barrel into which a stationary tube for air supply and exhaust is inserted is rotatably housed in a vacuum container, the vacuum container is located opposite to the baffle plate attachment position of the rotating barrel. 1. A gas centrifuge, characterized in that an electrode is installed on the inner surface of the rotating body at an appropriate distance from the rotating body, and a negative DC voltage is applied to the electrode. 2. The gas centrifuge according to claim 1, wherein the electrode is installed in a molecular pump provided on the inner surface of the upper part of the vacuum container. 3. The gas centrifuge according to claim 1, wherein the electrode is a needle-like electrode, and a plurality of needle-like electrodes are arranged and installed in the circumferential direction and the axial direction. 4. The gas centrifuge according to claim 3, wherein the needle electrode is formed to protrude from the inner periphery of the annular conductor.