JPS603843A - X-ray tube - Google Patents

Abstract

PURPOSE:To improve the cooling efficiency of an anode body by providing multiple lugs on a heat transfer surface on the operating liquid side. CONSTITUTION:An electron beam emitted from a cathode enters an anode body 1, part of it is radiated outside as X-ray energy, but most of it is absorbed by the anode as a heat loss. The heat generated in the anode body 1 is transferred to an operating liquid 6 through the heat transfer surface 12 of a metal lump 2. Multiple rectangular pyramidal projections 13 are provided on the heat transfer surface of the metal lump 2. Accordingly, the boiling of the operating liquid 6 first occurs at the base 14 of the projection 13 and the film formation gradually proceeds to the tip 16 of the projection 13, thereby the cooling efficiency can be improved as compared with the case of a flat heat transfer surface.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to a metal block having an anode body onto which an electron beam is incident, a heat transfer member protruding outward from the metal block, and a heat transfer member of the heat transfer member. The present invention relates to an X-ray tube equipped with a cooling means disposed at the other end, and particularly relates to a cooling structure suitable for an X-ray tube that has a large amount of heat incident on the anode body, such as for head computers, tomography, and the like.

[Background of the invention]

A conventional X-ray tube has a structure as shown in Japanese Utility Model Application No. 55-124762. As shown in FIG. 1, this structure has a metal block 2 at one end which has an anode body I disposed opposite to a cathode (not shown), and a heat transfer member 3 at the other end. A cooling means 4 is attached to the other end of this heat transfer member 3 with a screw 5.
I'm being kicked. A hollow portion communicating with the heat transfer member 3 and the cooling means 4 is formed, and an evaporative working fluid 6 and a partition plate 7 are housed in this hollow portion. A glass tube 9 is connected to the outside of the heat transfer member 3 via a glass seal fitting 8, and the cathode portion Cζ of the glass tube 9 is sealed.

Therefore, the electron beam emitted from the cathode enters the anode body, and a portion is emitted to the outside as X gland energy, but the majority is absorbed by the anode and results in heat loss. The heat generated in the anode body 1 is transferred from the heat transfer surface IO of the metal lump 2 to the working fluid 6. When the temperature of the working fluid 6 exceeds the boiling point, bubbles are generated on the heat transfer surface 10, and the working fluid 6 vaporizes and carries away a large amount of heat of vaporization, thereby cooling the heat transfer surface 10. A phenomenon called evaporative cooling or boiling cooling occurs. The bubbles generated on the heat transfer surface 10 pass through the hollow part of the heat transfer member 3 and pass through the cooling means 4.
It moves in this direction, gathers in the space 11 of the cooling means 4, loses heat by the cooling means 4, becomes a liquid phase, and returns to the working fluid 6 again.

By the way, since the conventional heat transfer surface 10 is planar, as the heat amount of the metal lump 2 increases, the bubbles generated on the heat transfer surface 10 are uniformly generated over the entire surface, and when the heat amount further increases, In this case, the heat transfer surface 10 is covered with air bubbles I and becomes entangled. This state is called film boiling, and has the drawback of reducing cooling efficiency and causing damage to the anode body 1.

[Purpose of the invention]

An object of the present invention is to provide an X-ray tube whose anode body can be sufficiently cooled and whose life can be extended.

[Summary of the invention]

The present invention is characterized in that a plurality of protrusions are provided on the heat transfer surface of the metal lump on the hydraulic fluid side.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be explained with reference to FIG. 2. In addition, the same reference numerals are given to the same or equivalent parts as in the first diagram,
The explanation will be omitted. A plurality of square pyramid-shaped projections 13 as shown in FIG. 3 are provided on the heat transfer surface 12 of the metal lump 2. As shown in FIG.

Therefore, boiling of the working fluid 6 first occurs at the root 14 of the protrusion 13, and as the amount of heat increases, the root 14 of the protrusion 13 becomes covered with a film of bubbles, and then from the root 14 of the protrusion 13 to the side wall.
5 begins to be covered with a film, and film formation gradually progresses to the tip 16 of the protrusion 13.

In this way, since the film formation gradually progresses from the root 14 of the protrusion 13 to the tip 16, the cooling efficiency is improved compared to a conventional flat heat transfer surface.

Note that the shape of the protrusion 13 is not particularly limited;
For example, the shape may be a triangular pyramid, a hemisphere, a cylinder, a circle #ffj, or the like. Also in this embodiment, a partition plate 7 may be provided as in the case of FIG.

Next, although not directly related to the gist of the present invention, a structure that eliminates another drawback of the structure shown in FIG. 1 will be described. As explained in FIG. 1, the heat generated in the anode body 1 is transferred from the heat transfer surface 10 of the metal lump 2 to the working fluid 6, and when the temperature of the working fluid 6 exceeds the boiling point, bubbles are formed on the heat transfer surface 10. The working fluid 6 vaporizes and absorbs a large amount of heat of vaporization. If these bubbles do not separate from the heat transfer surface and remain in close contact with the heat transfer surface, no new bubbles will be generated, resulting in a significant drop in cooling efficiency.

4 ~ By the way, bubbles generated on the heat transfer surface 10 initially move away from the heat transfer surface 10 and into the hollow inner wall 17 of the heat transfer section 3, but when the X-ray tube is used horizontally, “Since the blank wall 17 is horizontal, the air bubbles in the hollow inner wall 17 move toward the space 11, 1lCI, ).For this reason, the air bubbles on the heat transfer surface 10 ?f
There was also a problem that peeling of iI occurred and resulted in another F, resulting in a decrease in cooling ability and damage to the anode body 1.

These drawbacks can be overcome by forming the hollow inner wall of the heat transfer section 3 into a conical hollow inner wall 18 as shown in FIG. That is, the bubbles generated on the heat transfer surface easily rise along the conical hollow inner wall 18 and move toward the cooling means 4 side. Therefore, the heat transfer surface 10 is always covered with a liquid phase and is sufficiently cooled. Further, the anode body 1 side of the conical hollow inner wall 18 also acts as a heat transfer surface.

Therefore, the hollow inner wall of the heat transfer member 3 is made into a conical hollow inner wall 18, and the heat transfer surface 10 is made into a heat transfer surface 12 shown in FIG.
3 improves the cooling efficiency of the barrel.

〔Effect of the invention〕

According to the present invention, a plurality of
Since the protrusion is provided, the cooling efficiency of the anode body is improved,
Excellent reliability and long life.

[Brief explanation of drawings]

Figure @1 is a cross-sectional view of the anode side cooling 41 structure of a conventional X-ray tube.
Fig. 2 is a sectional view showing an embodiment of the anode side cooling borrow of the X-ray tube according to the present invention, Fig. 3 is a perspective view of the heat transfer surface of Fig. 2, and Fig. 4 is an anode of the X-ray tube. (It is a sectional view showing another example of the flll cooling tower. 1...Anode body, 2...Metal lump, 3...Heat transfer section, 4...Cooling means, 6... Hydraulic fluid, 12...
・Heat transfer surface, 13...Protrusion. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A metal block having an anode body, a heat transfer member protruding from the metal block to the outside and having an evaporative working fluid sealed inside, and a cooling means disposed at the other end of the heat transfer member. An X-ray tube comprising several protrusions on the heat transfer surface of the metal block on the working fluid side.