JP3155347B2 - Cooling device for rotating X-ray cathode tubes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating anode X-ray tube provided in an X-ray generator, and more particularly to a cooling device for cooling the rotating anode of the X-ray tube.

[0002]

2. Description of the Related Art Conventionally, a rotating cathode X-ray tube provided in an X-ray generating apparatus circulates cooling water to cool heat generated when an electron beam collides with a rotating cathode. It is a structure that can be done.

FIG. 4 is a front sectional view showing a conventional rotary anti-cathode X-ray tube cooling device. The rotating anti-cathode 10 has a rotating shaft 1
1, and rotates at high speed by receiving a driving force from a rotation driving source (not shown). The rotating shaft 11 is rotatably supported by a bearing 13 provided on a housing 12. The rotating shaft 11 is formed in a hollow shape, and the hollow portion serves as a water supply passage 20 for introducing cooling water. The water supply passage 20 is open inside the rotating anode 10. Further, the water supply passage 20 communicates with a drain passage 22 formed from the inside of the rotary anti-cathode 10 to the hollow portion of the rotary shaft 11 with a partition wall 21 interposed therebetween. Water is discharged to the outside through the drain passage 22. The partition 21 is fixed, and the rotating shaft 11 and the rotating anode 10 are surrounded therearound.
Rotates at high speed.

[0004] The tip of the partition 21, that is, the communicating portion between the water supply passage 20 and the drain passage 22 is connected to the rotating anode 10.
Are formed in the vicinity of the inner wall, thereby forming a narrow cooling water conducting portion 23. Therefore, the cooling water sent from the water supply passage 20 by the pressure feed pump (not shown) increases the flow velocity in the conduction part 23 and the rotating counter cathode 1
After absorbing the heat generated at zero, the heat is immediately sent to the drain passage 22. In addition, a seal member 16 is provided at a boundary between the rotating shaft 11 and the bearing 13 which are in contact with the water supply passage,
The cooling water flowing through the water supply passage 20 is prevented from leaking to the bearing 13 side.

[0005]

In the above-described conventional cooling apparatus for a rotating anode X-ray tube, it is necessary to circulate a large amount of cooling water in order to effectively cool the heated rotating anode 10. . For example, if the load capacity of the rotating anode 10 is 18
For an X-ray tube of about KW, 12 to 18 liters of cooling water per minute had to be sent to the heat generating part. Therefore, a large-sized pump is required, and there is a problem that the equipment cost is high.

In addition, since the viscous resistance of the cooling water increases in the narrow conduction portion 23, a large load is applied to a drive motor (not shown) for rotating the rotating anode 10 at a high speed.
Therefore, a high output drive motor is required,
From this point, there is a problem that the equipment cost becomes high.
In addition, the vibrating resistance of the cooling water causes the rotation shaft 11 to oscillate, which may cause vibration.

Furthermore, in the above-described conventional cooling device, a pressure pump is provided at the start end of the water supply passage to feed the cooling water. In such a structure, the pressure of the cooling water causes the seal member 16 to move outward. Because it works to push out,
When the seal member 16 is deteriorated, there is a risk that the cooling water leaks to the outside.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and has a low equipment cost, can prevent unnecessary rotation of the rotating shaft, and has a sealing member in contact with the discharge side passage. It is an object of the present invention to provide a cooling apparatus for a rotating cathode X-ray tube that can prevent leakage of a cooling medium even when the seal member is deteriorated.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, a cooling apparatus for a rotating anode X-ray tube according to the present invention comprises a supply passage for supplying a liquefied cooling medium and a discharge communicating with the supply passage. A cooling medium ejecting means provided at a boundary between the supply-side passage and the discharge-side passage; and a decompression suction means for reducing the pressure in the discharge-side passage and sucking the cooling medium. It is characterized in that the means is arranged inside the rotating anode.

[0010]

The liquefied cooling medium supplied to the supply side passage reaches the cooling medium ejecting means disposed inside the rotating counter cathode by the suction force of the reduced pressure suction means. Then, the cooling medium jetted from the cooling medium jetting means to the discharge side passage in a reduced pressure state has a lower boiling point and is vaporized at a low temperature. At this time, the heat of the rotating anode is absorbed by the heat of vaporization. The cooling medium that has absorbed the heat is sent to the outside from the discharge-side passage in a gaseous state.

As described above, since the rotating anode is cooled by the heat of vaporization, the cooling efficiency is high, and the supply amount of the cooling medium is small. Further, since the cooling medium is a gas inside the rotating anti-cathode that rotates at a high speed, the viscous resistance is low, and therefore the load on the drive motor that rotates the rotating anti-cathode is small. Further, since the inside of the passage is suctioned under reduced pressure on the discharge side of the cooling medium, even if the seal member is deteriorated, only the outside air enters into the discharge side passage, and the cooling medium in the passage is discharged to the outside. Do not leak.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front cross-sectional view showing a rotating-cathode X-ray tube cooling device according to an embodiment of the present invention. FIG.
FIG. 3 is an enlarged front sectional view showing the periphery of the cooling medium ejection means in FIG. 1, and FIG. 3 is a piping diagram of the present apparatus.

The cooling apparatus according to the present embodiment includes a supply side passage 1 for supplying cooling water as a cooling medium, a discharge side passage 2 for absorbing heat and evaporating steam as described later, and a boundary between these passages. A nozzle 3 as a cooling medium ejection means provided;
And a vacuum pump 5 as a reduced pressure suction means provided in the middle of a pipe 4 connected to the discharge side passage 2. The supply-side passage 1 is formed by a partition wall 14 installed from the hollow portion of the rotating shaft 11 to the inside of the rotating anti-cathode 10.
The bearing 13 has a supply port 1a on the base end side thereof.
a communicates with a cooling water supply source (not shown) via a pipe 6. On the other hand, the nozzle 3
Is provided. The partition wall 14 has a base end fixed to the housing 12, and includes a rotating shaft 11 and a rotating anode 1.
0 holds a fixed state inside.

As shown in FIG. 2, the nozzle 3 is installed facing the inner surface of the peripheral wall 10a of the rotating anode 10. In particular, in the present embodiment, the nozzle 3 is provided so as to face the inner surface of the peripheral wall at the portion where the electron beam emitted from the electron gun 15 collides (see FIG. 1). This is for the purpose of efficiently cooling the peripheral wall portion because the portion where the electron beam collides generates the highest heat. The discharge side passage 2 includes a rotating anode 1
It is formed from the sealed hollow portion 2a inside the hollow portion 2 to the hollow portion 2b of the rotary shaft 11, and is in contact with the seal member 16 of the rotary shaft 11 on the way. The pressure in the discharge side passage 2 is reduced to, for example, 75 to 50 torr by the vacuum pump 5.
In FIG. 1, 31 indicates an X-ray transmission window, and 32 indicates a vacuum seal.

Next, the operation of cooling the rotating anode by the cooling device having the above-described configuration will be described. By the suction force of the vacuum pump 5, the cooling water is sent from the cooling water supply source (not shown) to the supply side passage 1 through the pipe 6. The cooling water sent into the supply-side passage is jetted from the nozzle 3 into the discharge-side passage 2 inside the rotating anode 10. Discharge side passage 2
Since the inside is depressurized by the vacuum pump 5, the cooling water jetted into the discharge side passage 2 has a lower boiling point and evaporates at a low temperature. Therefore, the cooling water (vapor) vaporized in the discharge side passage 2 absorbs the heat generated on the peripheral wall 10a of the rotating anode 10 by the heat of vaporization, and as a result, the rotating anode 10 is cooled. The steam that has absorbed heat from the rotating anode 10 is discharged to the outside through the pipe 4 through the discharge side passage 2 b in the rotating shaft 11 by the suction force of the vacuum pump 5.

As described above, in the present embodiment, in which the cooling water is evaporated under reduced pressure and the rotary anode 10 is cooled by the heat of vaporization, for example, the rotary anode having a load capacity of 18 KW is cooled. It is only necessary to supply about 1 liter of cooling water per minute. Further, although the space between the nozzle 3 and the peripheral wall 10a of the rotating anode 10 facing the nozzle 3 is small, the cooling water is vaporized in the space. There is no such viscous resistance, so that there is no run-out of the rotating shaft 11. Furthermore, a low-torque motor for driving the rotating anti-cathode 10 is sufficient, and the equipment cost can be reduced.

When the seal member 16 of the rotating shaft 11 is deteriorated due to abrasion or the like, external air may enter the discharge passage 2 in a reduced pressure state. As a result, although the pressure in the discharge passage 2 slightly increases, the cooling steam in the discharge passage 2 does not leak to the outside, so that the surroundings of the rotation axis are not contaminated with the cooling water.

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications and applications are possible without changing the gist of the invention. For example, the reduced pressure value of the discharge side passage should be experimentally determined so that the cooling water absorbs the heat of the rotating anti-cathode and evaporates according to the relationship with the heat generation temperature of the rotating anti-cathode. The supply-side passage may be opened in a plurality of directions (both in a direction toward the inner surface of the peripheral wall of the same counter electrode) inside the rotating counter electrode, and a cooling medium ejection unit may be provided in each opening.

[0019]

As described above, according to the rotating cathode X-ray tube cooling apparatus of the present invention, the cooling medium is vaporized under reduced pressure, and the rotating heat is cooled by the heat of vaporization. Therefore, the resistance to the rotating anti-cathode rotating at high speed and the supply amount of the cooling medium can be reduced, and as a result, there is an effect that the swing of the rotating shaft can be prevented and the equipment cost can be reduced. In addition, when there is a seal member in contact with the discharge side passage, leakage of the cooling medium can be prevented even when the seal member is deteriorated.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a cooling apparatus for a rotating cathode X-ray tube according to an embodiment of the present invention.

FIG. 2 is an enlarged front cross-sectional view showing a peripheral portion of a cooling medium jetting means in the same device.

FIG. 3 is a piping diagram of the same device.

FIG. 4 is a front sectional view showing a conventional rotating anti-cathode X-ray tube cooling device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Supply side passage 2 Discharge side passage 3 Nozzle (cooling medium ejection means) 4 Piping 5 Vacuum pump (decompression suction means) 10 Rotational cathode 11 Rotation shaft 12 Housing 13 Bearing 14 Partition wall 15 Electron gun

Claims (2)

(57) [Claims] A supply-side passage for supplying a liquefied cooling medium; a discharge-side passage communicating with the supply-side passage; a cooling-medium ejecting means provided at a boundary between the supply-side passage and the discharge-side passage; A cooling device for a rotating-cathode X-ray tube, comprising: decompression suction means for reducing the pressure in the discharge-side passage and sucking a cooling medium, wherein the cooling-medium ejection means is disposed inside the rotating anti-cathode. 2. A cooling apparatus for a rotating cathode X-ray tube according to claim 1, wherein said cooling medium jetting means is arranged so as to face an inner surface of a peripheral wall of the rotating anode which generates heat by collision of an electron beam. .