CN112563096A - Medical X-ray tube with large thermal capacity - Google Patents

Abstract

The invention discloses a medical X-ray tube with large heat capacity, which comprises a metal shell, an anode shell, a cathode shell, a bearing, a target disc, a cathode assembly, a ray output window and an exhaust pipe, wherein the anode shell comprises anode ceramic which is internally corrugated ceramic, the cathode shell comprises cathode ceramic, and the outer wall of the cathode shell is of a corrugated structure. The invention adopts the structure of the ceramic with the corrugated outside the cathode, the metal shell and the ceramic with the corrugated inside the anode to effectively solve the heat dissipation problem of the X-ray tube with large heat capacity; the cathode shell adopts an external corrugated ceramic structure, so that the surface area of the cathode shell is increased, the heat dissipation capacity of the cathode shell is greatly improved, and the heat in the X-ray tube can be effectively led out of the X-ray tube in time; the anode shell adopts an anode ceramic structure to replace the original glass, so that the heat resistance and the anti-creep capacity of the X-ray tube are effectively improved, and the reliability of the X-ray tube is improved; the anode ceramic is internal corrugated ceramic, the creepage distance is increased, the internal interval of the anode ceramic is lengthened, and the sufficient insulation strength is ensured.

Description

Medical X-ray tube with large thermal capacity

Technical Field

The invention relates to the technical field of medical detection and ray metering detection, in particular to a medical X-ray tube with large heat capacity.

Background

The X-ray tube is mainly used for medical equipment such as an X-ray machine, a CT machine and the like, and generates X-rays under the action of external high pressure, so that doctors can diagnose or treat patients.

Filament electron cloud of the X-ray tube is accelerated to strike an anode target plate under the action of negative high voltage of a cathode and positive high voltage of an anode to generate X-rays, effective X-rays are output by a ray window, but only 1% of the effective X-rays are generated, and the rest 99% of energy is completely converted into heat which is transmitted to the outside of the X-ray tube through different channels and is taken away by an X-ray tube sleeve and an X-ray tube radiator.

The traditional X-ray tube mainly adopts a glass insulation structure, and has: cathode glass-intermediate metal-anode glass structure or monolithic glass-cathode metal-anode metal structure, both of which are unsuitable for use in large heat capacity X-ray tubes due to strength and stress problems of the glass, mainly because:

1. with glass insulation, especially the anode glass bulb, 20% of the heat of the target disk is radiated outside the X-ray tube through the glass, and because the softening temperature of the glass is low (the softening temperature is 550 ℃) and the fatal defect of TK100 value exists, the discharge phenomenon is easy to generate when the heat is too concentrated. (Note: TK100 means that the insulation strength rapidly decreases when the glass reaches a certain temperature point, and the TK100 value of the glass of an X-ray tube is about 300 degrees).

2. The glass sealing part has low mechanical strength, the anode glass shell bears the weight of the target disc and the bearing, the cathode glass shell bears the weight of the cathode head and the core column, and the coaxiality of the glass and kovar can be ensured only manually in the sealing process of the glass, so that stress is inevitably generated during welding in the technological process, and the glass can generate cracks or explosion points under certain heat conditions.

3. The process is complex, and has a plurality of welding seams, referring to fig. 4 (X-ray tube in the prior art), 3 welding seams exist at the cathode part, so that one more welding seam has the possibility of air leakage, and the process is complex because necessary process steps are added to avoid air leakage to ensure the reliability of the welding seam.

Therefore, there is a need to provide a new medical X-ray tube with a large heat capacity to solve some of the problems of the prior art.

Disclosure of Invention

The invention aims to provide a medical X-ray tube with high heat capacity and good heat dissipation effect so as to solve the problems in the prior art.

In order to achieve the purpose, the invention adopts a technical scheme that: the utility model provides a medical X-ray tube of big thermal capacity, its includes metal casing, connects respectively the positive pole casing and the cathode casing at metal casing both ends, connect the inside bearing of positive pole casing, with target dish, connection that the bearing is connected are in the inside negative pole subassembly of cathode casing, set up ray output window on the metal casing and with the blast pipe that metal casing connects, the target dish is acceptd in the metal casing, the positive pole casing include positive pole pottery and with the positive pole heat conduction metal that positive pole pottery is connected, positive pole pottery with metal casing connects, positive pole pottery is interior ripple pottery, sets up a plurality of evenly distributed's ceramic recess on its inner surface, the cathode casing includes negative pole pottery, the outer wall of negative pole pottery is the ripple structure.

The metal shell is made of a special heat-dissipation metal material which is a copper-nickel alloy, wherein the proportion of nickel is more than 40%.

The target disc is of a long hollow structure and comprises target disc graphite, and the bearing is connected to one end, far away from the target disc graphite, of the target disc.

The anode shell further comprises an anode shielding ring, the anode shielding ring is connected between the anode ceramic and the metal shell, and a plurality of anode shielding ring slots are formed in the anode shielding ring.

The ceramic both ends of positive pole are connected with positive pole little kovar respectively and positive extremely big kovar, positive pole little kovar with positive pole heat conduction metal is connected, positive extremely big kovar with positive pole shielding ring connects.

The little kovar of positive pole with the junction of positive pole heat conduction metal is equipped with first positive pole end seal, and both adopt terminal surface argon arc to weld and link together, the positive pole greatly kovar with the junction of positive pole shielding ring is equipped with second positive pole end seal, and both adopt terminal surface argon arc to weld and link together.

The cathode shell further comprises a cathode kovar connected to the end part of the cathode ceramic, and the cathode ceramic and the cathode kovar are formed through one-step welding through high-temperature brazing.

The cathode assembly comprises a fixed sleeve connected inside the cathode ceramic, a core column connected inside the cathode ceramic and a getter connected on the core column, an exhaust filament connected with the fixed sleeve and a cathode head located on the side edge of the exhaust filament, wherein the cathode ceramic, the fixed sleeve, the core column and the cathode kovar are integrally formed through high-temperature brazing of a die.

Cathode pottery includes negative pole ripple ceramic pipe and connects ceramic connecting portion in the negative pole ripple ceramic pipe, the stem is connected on the ceramic connecting portion, fixed cover is connected one side of ceramic connecting portion.

Compared with the prior art, the medical X-ray tube with large heat capacity has the beneficial effects that: the heat dissipation problem of the X-ray tube with large heat capacity is effectively solved by adopting a cathode external corrugated ceramic-metal shell-anode internal corrugated ceramic structure; the cathode shell adopts an external corrugated ceramic structure, so that the surface area of the cathode shell is increased, the heat dissipation capacity of the cathode ceramic is greatly improved, and the heat in the X-ray tube can be effectively led out of the X-ray tube in time; the anode shell adopts an anode ceramic structure to replace the original glass, so that the heat resistance and the anti-creep capacity of the X-ray tube are effectively improved, and the reliability of the X-ray tube is improved; the anode ceramic is internal corrugated ceramic, the creepage distance is increased, the internal interval of the anode ceramic is lengthened, and the sufficient insulation strength is ensured.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without inventive efforts, wherein:

FIG. 1 is a schematic view of a high thermal capacity medical X-ray tube of the present invention;

FIG. 2 is a schematic view of an anode casing of the present invention;

FIG. 3 is a schematic view of a cathode casing and cathode assembly of the present invention;

fig. 4 is a schematic view of a prior art X-ray tube.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1 to 4, the present invention is a medical X-ray tube with large thermal capacity, which includes ametal casing 1, ananode casing 2 and acathode casing 3 respectively connected to two ends of themetal casing 1, abearing 4 connected to the inside of theanode casing 2, atarget disk 5 connected to thebearing 4, acathode assembly 6 connected to the inside of thecathode casing 3, aradiation output window 7 opened on themetal casing 1, and anexhaust pipe 8 connected to themetal casing 1, wherein thetarget disk 5 is accommodated in themetal casing 1.

Themetal shell 1 is made of a special heat dissipation metal material which is a copper-nickel alloy, wherein the proportion of nickel is more than 40%, the copper-nickel alloy is a material which is existed in recent years, and the copper-nickel alloy is not adopted in an X-ray tube, is easy to process, has high heat dissipation performance, and can replace transition metal in an original output structure.

Referring to fig. 1 and 2, theanode casing 2 includes an anode ceramic 21 and an anodeheat conducting metal 22 connected to the anode ceramic 21, and theanode ceramic 21 is connected to themetal casing 1. Theanode ceramic 21 is used for replacing the original glass, so that the heat resistance and the anti-creep capacity of the X-ray tube can be effectively improved, and the reliability of the X-ray tube is improved; the anode ceramic 21 is 95%, 97% and 99% of aluminum oxide industrial ceramic, and as the ceramic can resist 1400 ℃ high temperature, the capability of bearing secondary electron bombardment is far higher than that of glass, the service life of the X-ray tube is prolonged. The ceramic 21 of positive pole is interior ripple pottery, has seted up a plurality of evenly distributed'sceramic recess 23 on its inner surface, and with the ceramic 21 design of positive pole for interior ripple pottery, increase creepage distance, make the inside interval ofpositive pole pottery 21 elongate, guarantee sufficient dielectric strength.

Theanode shell 2 further comprises ananode shielding ring 24, theanode shielding ring 24 is connected between the anode ceramic 21 and themetal shell 1, a plurality of anodeshielding ring slots 25 are formed in theanode shielding ring 24, theanode shielding ring 24 is additionally arranged between the anode ceramic 21 and thetarget disc 5, the brazing surface is guaranteed not to be heated and not to be impacted by secondary electrons, and the reliability of the X-ray tube is improved.

Two ends of the anode ceramic 21 are respectively connected with an anodesmall kovar 26 and an anodelarge kovar 27, the anodesmall kovar 26 is connected with the anodeheat conducting metal 22, and the anodelarge kovar 27 is connected with theanode shielding ring 24. The junction of the anodesmall kovar 26 and the anodeheat conducting metal 22 is provided with a firstanode end seal 28, and the two are connected together by end face argon arc welding. The junction of the anodelarge kovar 27 and theanode shielding ring 24 is provided with a secondanode end seal 29, and the anodelarge kovar 27 and the anode shielding ring are connected together by end face argon arc welding. Because two parts welded by argon arc welding are welded by thin walls, the welding reliability is improved, and because theanode minimum kovar 26 and the anodeheat conducting metal 22 as well as the anodemaximum kovar 27 and theanode shielding ring 24 adopt end sealing structures, the welding flux, the metal and the ceramic form an arc-shaped welding infiltration angle, the welding intensity is very high, and the use reliability of the whole X-ray tube under high centrifugal force can be improved.

Referring to fig. 1, thetarget plate 5 is a long hollow structure, and includes a target plate graphite 51, and thebearing 4 is connected to an end of thetarget plate 5 away from the target plate graphite 51, so that thebearing 4 is away from the high temperature region of thetarget plate 5, thereby improving the reliability of thebearing 4.

Referring to fig. 1 and 3, thecathode housing 3 includes a cathode ceramic 31, and an outer wall of the cathode ceramic 31 has a corrugated structure, so that a surface area of the cathode ceramic 31 is increased, a heat dissipation capability of the cathode ceramic 31 is greatly improved, and heat in the X-ray tube can be effectively conducted out of the X-ray tube in time. The cathode ceramic 31 is made of 95%, 97% or 99% alumina industrial ceramic. Thecathode shell 3 further comprises acathode kovar 32 connected to the end portion of the cathode ceramic 31, the cathode ceramic 31 and thecathode kovar 32 are formed through one-step welding through high-temperature brazing, thecathode kovar 32 and themetal shell 1 are connected together in an end seal welding mode, and welding reliability is improved.

Thecathode assembly 6 includes afixing sleeve 61 connected to the inside of the cathode ceramic 31, astem 62 connected to the cathode ceramic 31 and accommodated in thefixing sleeve 61, agetter 63 connected to thestem 62, anexhaust filament 64 connected to thefixing sleeve 61, and acathode head 65 located at a side of theexhaust filament 64, and the cathode ceramic 31, thefixing sleeve 61, thestem 62, and thecathode kovar 32 are integrally formed by high temperature brazing using a die. As can be seen from the comparison of thecathode assembly 6 and thecathode housing 3 with the prior art X-ray tube (see fig. 4), which has only oneweld 10, and the prior art X-ray tube has three welds, i.e., weld one 101, weld two 102, and weld three 103, the joint strength at the weld is much lower than that of the integrated structure, and the X-ray tube now has one third of the probability of cracking and air leakage for the three welds. Thecathode component 6 is additionally provided with theexhaust filament 64, theexhaust filament 64 is used in the production process of the X-ray tube, and because the working temperature of the X-ray tube is high, the exhaust temperature in the production process is far higher than the temperature of the X-ray tube in use, the load of the normal filament is difficult to realize the highest temperature in exhaust, the exhaust filament is additionally arranged to ensure that the X-ray tube can reach the limit temperature in exhaust, so that no residual gas is discharged in normal use of the X-ray tube, and the reliability of the X-ray tube is improved; thegetter 63 is adopted, the getter is required to be activated during exhaust, residual gas in the tube is absorbed during aging, thegetter 63 can be subjected to chemical reaction with the residual gas in the X-ray tube, the gas suction process is irreversible, the vacuum degree in the X-ray tube can be improved by 1 order of magnitude, the phenomenon of intense fire of the X-ray tube in the use process is greatly reduced, even the fire is not struck, and the image quality of the CT machine is ensured.

The cathode ceramic 31 includes a cathode corrugatedceramic tube 311 and a ceramic connectingportion 312 connected in the cathode corrugatedceramic tube 311, thestem 62 is connected to the ceramic connectingportion 312, and thefixing sleeve 61 is connected to one side of the ceramic connectingportion 312.

According to the medical X-ray tube with the large heat capacity, the heat dissipation problem of the X-ray tube with the large heat capacity is effectively solved by adopting the structure of the cathode outer corrugated ceramic, the metal shell and the anode inner corrugated ceramic, the surface area of the cathode shell is increased by adopting the outer corrugated ceramic structure of the cathode shell, the heat dissipation capacity of the cathode ceramic is greatly improved, and the heat in the X-ray tube can be timely and effectively led out of the X-ray tube; the anode shell adopts an anode ceramic structure to replace the original glass, so that the heat resistance and the anti-creep capacity of the X-ray tube are effectively improved, and the reliability of the X-ray tube is improved; the anode ceramic is internal corrugated ceramic, the creepage distance is increased, the internal interval of the anode ceramic is lengthened, and the sufficient insulation strength is ensured.

Of course, those skilled in the art will recognize that the above-described embodiments are illustrative only, and not intended to be limiting, and that changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (9)

1. A medical X-ray tube of high thermal capacity, characterized by: it includes metal casing, connects respectively the positive pole casing and the negative pole casing at metal casing both ends, connect the inside bearing of positive pole casing, with target dish, connection that the bearing is connected the inside negative pole subassembly of negative pole casing, set up ray output window on the metal casing and with the blast pipe that metal casing connects, the target dish is acceptd in the metal casing, the positive pole casing include positive pole pottery and with positive pole heat conduction metal that positive pole pottery is connected, positive pole pottery with metal casing connects, positive pole pottery is interior ripple pottery, sets up a plurality of evenly distributed's ceramic recess on its inner surface, the negative pole casing includes negative pole pottery, the outer wall of negative pole pottery is the ripple structure.

2. The large heat capacity medical X-ray tube of claim 1, wherein: the anode shell further comprises an anode shielding ring, the anode shielding ring is connected between the anode ceramic and the metal shell, and a plurality of anode shielding ring slots are formed in the anode shielding ring.

3. The large heat capacity medical X-ray tube of claim 2, wherein: the ceramic both ends of positive pole are connected with positive pole little kovar respectively and positive extremely big kovar, positive pole little kovar with positive pole heat conduction metal is connected, positive extremely big kovar with positive pole shielding ring connects.

4. A large heat capacity medical X-ray tube according to claim 3, wherein: the little kovar of positive pole with the junction of positive pole heat conduction metal is equipped with first positive pole end seal, and both adopt terminal surface argon arc to weld and link together, the positive pole greatly kovar with the junction of positive pole shielding ring is equipped with second positive pole end seal, and both adopt terminal surface argon arc to weld and link together.

5. The large heat capacity medical X-ray tube according to claim 4, wherein: the cathode shell further comprises a cathode kovar connected to the end part of the cathode ceramic, and the cathode ceramic and the cathode kovar are formed through one-step welding through high-temperature brazing.

6. The large heat capacity medical X-ray tube according to claim 5, wherein: the cathode assembly comprises a fixed sleeve connected inside the cathode ceramic, a core column connected inside the cathode ceramic and a getter connected on the core column, an exhaust filament connected with the fixed sleeve and a cathode head located on the side edge of the exhaust filament, wherein the cathode ceramic, the fixed sleeve, the core column and the cathode kovar are integrally formed through high-temperature brazing of a die.

7. The large heat capacity medical X-ray tube of claim 6, wherein: cathode pottery includes negative pole ripple ceramic pipe and connects ceramic connecting portion in the negative pole ripple ceramic pipe, the stem is connected on the ceramic connecting portion, fixed cover is connected one side of ceramic connecting portion.

8. The medical X-ray tube with large heat capacity as set forth in any one of claims 1 to 7, wherein: the metal shell is made of a special heat-dissipation metal material which is a copper-nickel alloy, wherein the proportion of nickel is more than 40%.

9. The large heat capacity medical X-ray tube of claim 8, wherein: the target disc is of a long hollow structure and comprises target disc graphite, and the bearing is connected to one end, far away from the target disc graphite, of the target disc.

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