Neutron source transmission gas path structure

Abstract

The utility model belongs to nuclear radiation technical field, specifically discloses a kind of neutron source transmission gas path structure, including the vertically arranged transmission pipeline and be located in the neutron source cup of transmission pipeline, neutron source cup is used to place neutron source;The lower end of transmission pipeline is equipped with sealing plate, transmission pipeline lower end is vertically equipped with gas tube, and total air inlet is set in the center of sealing plate, to communicate gas tube and transmission pipeline;Gas tube includes outer gas tube and the inner gas tube of being located in outer gas tube, and the inner gas tube axis, outer gas tube axis and total air inlet vertical center line are collinear, and the upper end of inner gas tube and outer gas tube is flush with the top surface of sealing plate;First air inlet is equipped in the lower end of inner gas tube, and first air inlet is connected with first air pipe line, and the through-hole for first air pipe line is equipped on outer gas tube;Second air inlet is equipped in the lower end of outer gas tube, and second air inlet is connected with second air pipe line.The utility model can improve the stability in the process of neutron source lifting, avoid that neutron source cup and transmission pipeline rub.

Description

Technical Field

[0001] This utility model belongs to the field of nuclear radiation technology, specifically relating to a neutron source transmission gas path structure. Background Technology

[0002] Radioactive isotope neutron sources are small in size and simple in structure, and are widely used in various research fields such as instrument detection, irradiation breeding, neutron therapy, and neutron radiography. However, neutrons are ionizing radiation with extremely strong penetrating power, and the radiation dose received by experimental personnel should be minimized as much as possible during use.

[0003] When using a neutron source for irradiation, the neutron source needs to be transferred from its shielded container (storage location) to the designated irradiation position, and then returned to the shielded container after irradiation. Pneumatic transfer utilizes a gas-driven circuit, using gas pressure to raise and lower the neutron source, offering flexibility and ease of operation. However, in existing pneumatic transfer technology, the neutron source has low stability during raising and lowering, leading to friction and collisions between the neutron source cup and the transfer pipe. Over time, this increases the gap between the neutron source cup and the transfer pipe, reducing the pneumatic thrust and preventing the neutron source from rising properly. Furthermore, if this fails, the neutron source cup or transfer pipe needs to be replaced to ensure normal source raising. However, due to the ionizing radiation risk of the neutron source, replacing the transfer pipe increases the radiation risk. Replacing the neutron source cup, in particular, requires transporting it to the manufacturer's hot chamber, making the transportation and transfer of the neutron source complex and costly. Utility Model Content

[0004] In view of the above-mentioned shortcomings of the existing technology, the purpose of this utility model is to provide a neutron source transmission gas path structure to improve the stability of the neutron source during the lifting and lowering process and avoid friction between the neutron source cup and the transmission pipe.

[0005] The technical solution of this utility model is implemented as follows: A neutron source transmission gas path structure includes a vertically arranged transmission pipe and a neutron source cup disposed within the transmission pipe, wherein the neutron source cup is used to hold the neutron source; the lower end of the transmission pipe is provided with a sealing plate to seal the lower end of the transmission pipe, and a gas pipe is vertically arranged at the lower end of the transmission pipe, and a main air inlet is opened at the center of the sealing plate, thereby connecting the gas pipe and the transmission pipe.

[0006] The trachea includes an outer trachea and an inner trachea located inside the outer trachea. The axis of the inner trachea, the axis of the outer trachea, and the vertical center line of the main air inlet are collinear. The upper ends of the inner and outer tracheas are flush with the top surface of the sealing plate. The lower end of the inner trachea is provided with a first air inlet, which is connected to a first air inlet pipe. The outer trachea is provided with a through hole for the first air inlet pipe to pass through, so that the connection end of the first air inlet pipe can pass through the through hole and connect to the inner trachea. The lower end of the outer trachea is provided with a second air inlet, which is connected to a second air inlet pipe.

[0007] Furthermore, the inner air tube is supported and installed inside the outer air tube by several support plates, with the two ends of the support plates fixed to the outer wall of the inner air tube and the inner wall of the outer air tube, respectively.

[0008] Furthermore, all support plates are divided into at least two groups and arranged at intervals in the vertical direction, with each group of support plates evenly distributed along the circumference of the inner air tube.

[0009] Compared with the prior art, the present invention has the following beneficial effects: 1. The gas pipe of this utility model consists of an inner gas pipe and an outer gas pipe. The inner gas pipe is located inside the outer gas pipe, and the axis of the inner gas pipe, the axis of the outer gas pipe, and the vertical center line of the main air inlet are collinear. This ensures that air enters from the middle of the transmission pipe, effectively avoiding the eccentricity of the air inlet positions of the inner and outer gas pipes. This ensures that the neutron source cup remains vertically raised and lowered during the raising and lowering process, improves the stability of the neutron source during the raising and lowering process, avoids friction and collision between the neutron source cup and the inner wall of the transmission pipe, and ensures that the neutron source can rise normally.

[0010] 2. This utility model can raise the neutron source cup in a timely manner during the source raising process, and at the same time form an air cushion at the upper end of the inner gas tube during the source lowering process, thereby effectively buffering the neutron source cup and reducing the impact force between the neutron source cup and the bottom of the transmission pipe. Attached Figure Description

[0011] Figure 1 - A schematic diagram of the structure of this utility model.

[0012] Figure 2 - Schematic diagram of the shielding container and the neutron source transmission gas path.

[0013] Wherein: 1-Transmission pipe; 2-Neutron source cup; 3-Outer gas pipe; 4-Inner gas pipe; 5-Support plate; 6-First air inlet pipe; 7-Second air inlet pipe; 8-Shielding container. Detailed Implementation

[0014] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0015] The existing neutron source transmission gas path includes a vertically arranged transmission pipe with a sealing plate at its lower end to seal the lower end. A main air inlet is located at the center of the sealing plate, and a gas pipe is vertically arranged below the transmission pipe, corresponding to the main air inlet to connect the gas pipe and the transmission pipe. An air inlet is also provided on the gas pipe, which is connected to a gas source via an air inlet pipe to introduce gas into the gas pipe, which in turn introduces gas into the transmission pipe. The neutron source is placed in a neutron source cup, which is placed inside the transmission pipe. A spring is installed between the sealing plate and the neutron source cup. When the source needs to be raised, gas is introduced into the transmission pipe, driving the neutron source cup in the storage position to rise to the irradiation position, and then the gas source is shut off. When the source needs to be lowered, the neutron source cup descends, and the spring force cushions the neutron source cup, allowing it to return to the storage position. After prolonged operation, the spring will deform, making it impossible to ensure that the neutron source remains vertical during the lifting and lowering process. This will cause friction and collision between the neutron source cup and the inner wall of the transmission pipe, which will increase the gap between the neutron source cup and the transmission pipe, reduce the pneumatic transmission thrust, and prevent the neutron source from rising normally.

[0016] Based on this, the applicant conceived of the first technical solution: removing the spring and installing a regulating valve on the inlet pipe. This would allow for source raising and lowering by adjusting the flow rate of gas entering the pipe. Specifically, when source raising is needed, the regulating valve opening would be adjusted to introduce a larger flow of gas into the pipe; when source lowering is needed, the valve opening would be adjusted to introduce a smaller flow of gas, forming an air cushion to buffer the neutron source cup and allow it to fall smoothly to the storage position at the bottom of the transmission pipeline. However, the regulating valve opening gradually increases from 0 during operation, which limits the speed of source raising and lowering. This prevents the neutron source from being quickly raised to the irradiation position, affecting the timeliness of source raising, and also hinders the rapid attainment of the regulating valve opening required for source lowering, thus affecting the timeliness of source lowering.

[0017] Meanwhile, the applicant further optimized and improved the technology to obtain a second technical solution: two air inlets are set on the gas pipe, and the two air inlets are connected to the gas source through a first connecting pipe and a second connecting pipe, respectively. The opening and closing of the connecting pipes are controlled by a first solenoid valve and a second solenoid valve, respectively. The first connecting pipe is used to input a larger flow rate of gas, and the second connecting pipe is used to input a smaller flow rate of gas. When the source needs to be raised, the second solenoid valve is closed and the first solenoid valve is opened, allowing a larger flow rate of gas to enter the gas pipe to raise the source. When the source needs to be lowered, the first solenoid valve is closed and the second solenoid valve is opened, allowing a smaller flow rate of gas to enter the gas pipe to form an air cushion to buffer the neutron source cup, allowing the neutron source cup to fall smoothly to the storage position at the bottom of the transmission pipeline. However, in this way, during the source raising process, some of the gas entering the gas pipe will first enter the second connecting pipe, resulting in the source raising not being completed in time, and only after a period of time can the source raise be achieved; during the source lowering process, some of the gas entering the gas pipe will first enter the first connecting pipe, failing to form an air cushion at the main air inlet to buffer the neutron source cup in time.

[0018] Therefore, the applicant further optimized and improved the technical solution of this application: see Figure 1 A neutron source transmission gas path structure includes a vertically arranged transmission pipe 1 and a neutron source cup 2 disposed inside the transmission pipe 1. The neutron source cup 2 is used to place the neutron source. The lower end of the transmission pipe 1 is provided with a sealing plate to close the lower end of the transmission pipe 1. A gas pipe is vertically arranged at the lower end of the transmission pipe 1. A main air inlet is opened at the center of the sealing plate to connect the gas pipe and the transmission pipe 1.

[0019] The air pipe includes an outer air pipe 3 and an inner air pipe 4 located inside the outer air pipe 3. The axis of the inner air pipe 4, the axis of the outer air pipe 3, and the vertical center line of the main air inlet are collinear. The upper ends of the inner air pipe 4 and the outer air pipe 3 are flush with the top surface of the sealing plate. The lower end of the inner air pipe 4 is provided with a first air inlet, which is connected to a first air inlet pipe 6. The outer air pipe 3 is provided with a through hole for the first air inlet pipe 6 to pass through, so that the connecting end of the first air inlet pipe 6 can pass through the through hole and connect to the inner air pipe 4. The lower end of the outer air pipe 3 is provided with a second air inlet, which is connected to a second air inlet pipe 7.

[0020] The transmission pipeline is made of stainless steel, and its length can be adjusted according to the neutron source irradiation location; generally, the pipeline length is 3-5 meters. For usage instructions, please refer to [link / reference needed]. Figure 2The lower part of the transmission pipeline 1 and most of the gas pipe are located in the shielded container 8. The neutron source cup is placed at the bottom of the transmission pipeline 1 (storage location). The first air inlet pipe 6 and the second air inlet pipe 7 are located outside the shielded container. A first solenoid valve is installed on the first air inlet pipe 6, and a second solenoid valve is installed on the second air inlet pipe 7. When the source needs to be raised, the first solenoid valve is closed and the second solenoid valve is opened, allowing a larger flow of gas to be introduced into the outer gas pipe. Because the neutron source cup initially seals the upper end of the inner gas pipe, no gas will enter the inner gas pipe, thus allowing the neutron source cup to be raised. When the source needs to be lowered, the second solenoid valve is closed and the first solenoid valve is opened, allowing a smaller flow of gas to be introduced into the inner gas pipe. Although some gas enters the outer gas pipe during the neutron source's descent, the air pressure increases as the neutron source cup descends, and an air cushion is formed at the upper end of the inner gas pipe, effectively buffering the neutron source cup and reducing the impact force between the neutron source cup and the bottom of the transmission pipeline.

[0021] Meanwhile, in this technical solution, the inner air pipe axis, the outer air pipe axis, and the vertical center line of the main air inlet are collinear, which can effectively avoid the eccentricity of the air inlet positions of the inner and outer air pipes, ensuring that the neutron source cup always rises and falls vertically during the lifting and lowering process, improving the stability of the neutron source during the lifting and lowering process, avoiding friction and collision between the neutron source cup and the inner wall of the transmission pipeline, and ensuring that the neutron source can rise normally.

[0022] In specific implementation, the inner air tube 4 is supported and installed inside the outer air tube 3 by a number of support plates 5, and the two ends of the support plates 5 are respectively fixed to the outer wall of the inner air tube 4 and the inner wall of the outer air tube 3.

[0023] The support plates used here are very small and evenly distributed, so they have very little effect on the flow of gas in the external air tube.

[0024] In practice, all support plates 5 are arranged in at least two groups at intervals in the vertical direction, and each group of support plates 5 is evenly distributed along the circumference of the inner air tube 4. In this embodiment, two groups of support plates are arranged, located in the upper middle and lower middle parts of the inner air tube, respectively.

[0025] Finally, it should be noted that the above embodiments of this utility model are merely examples for illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make other variations and modifications based on the above description. It is impossible to exhaustively list all possible implementations here. All obvious variations or modifications derived from the technical solutions of this utility model are still within the protection scope of this utility model.

Claims

1. A neutron source transmission gas path structure, comprising a vertically arranged transmission pipe (1) and a neutron source cup (2) disposed within the transmission pipe (1), wherein the neutron source cup (2) is used to hold a neutron source; a sealing plate is provided at the lower end of the transmission pipe (1) to seal the lower end of the transmission pipe (1), and a gas pipe is vertically arranged at the lower end of the transmission pipe (1), with a main air inlet opened at the center of the sealing plate, thereby connecting the gas pipe and the transmission pipe (1); characterized in that: The trachea includes an outer trachea (3) and an inner trachea (4) located inside the outer trachea (3). The axis of the inner trachea (4), the axis of the outer trachea (3), and the vertical center line of the main air inlet are collinear. The upper ends of the inner trachea (4) and the outer trachea (3) are flush with the top surface of the sealing plate. The lower end of the inner trachea (4) is provided with a first air inlet, which is connected to a first air inlet pipe (6). The outer trachea (3) is provided with a through hole for the first air inlet pipe (6) to pass through, so that the connecting end of the first air inlet pipe passes through the through hole and connects to the inner trachea (4). The lower end of the outer trachea (3) is provided with a second air inlet, which is connected to a second air inlet pipe (7).

2. The neutron source transmission gas path structure according to claim 1, characterized in that, The inner air tube (4) is supported and installed inside the outer air tube (3) by several support plates (5), and the two ends of the support plates (5) are fixed to the outer wall of the inner air tube (4) and the inner wall of the outer air tube (3) respectively.

3. The neutron source transmission gas path structure according to claim 2, characterized in that, All support plates (5) are divided into at least two groups and are arranged at intervals in the vertical direction, and each group of support plates (5) is evenly distributed along the circumference of the inner air tube (4).

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