CN218579653U - Low radon emission rate high-temperature high-purity inert gas purifier - Google Patents

Abstract

A high-temperature high-purity inert gas purifier with low radon emissivity comprises a heat exchanger, branch pipelines, and an outlet pipeline, a main pipeline and an inlet pipeline which are sequentially connected; the branch pipeline is connected with the outlet pipeline and the inlet pipeline on the cold side of the heat exchanger, so that after the gas to be purified passes through the main pipeline, the purified gas is output to the inlet pipeline on the hot side of the heat exchanger through the outlet pipeline; the heat exchanger enables the gas to be purified to fully absorb the heat of the purified gas and enables the purified gas to be cooled to a safe temperature; the interior of the main pipeline is filled with high-purity metal filler. The utility model discloses thereby utilize metal such as low radioactivity high-purity metal zirconium, hafnium, iron, vanadium, titanium, copper through electron beam smelting or electrolytic refining to react with nitrogen, hydrogen, oxygen etc. element in the high-purity inert gas more than 600 ℃ and generate solid compound and realize the purification to high-purity inert gas, and it is effectual to high-purity inert gas's purification.

Description

Low radon emission rate high-temperature high-purity inert gas purifier

Technical Field

The utility model relates to a high-purity inert gas's purification technical field is a high-speed extremely trace elements such as N, O, H in getting rid of high-purity inert gas particularly to there is not obvious low radon emissivity high temperature high purity inert gas purifier that radioactive impurity such as radon harmful to the particle detector and other chemical impurity emitted simultaneously.

Background

Signals expected by rare case high-energy physical experiments such as dark matter detection, neutron-free double-beta decay detection and the like are very rare and weak, radioactive backgrounds need to be strictly controlled by materials for building the detector and detection media, and the problems of selection and source of low-radioactive background metal materials are a core problem to be solved in the field of rare case high-energy physical experiments. An inert gas such as xenon or argon is often used as a target substance of such a detector, and since a target particle emits free electrons when colliding with the target substance and impurity elements such as N, O, and H in the target substance absorb the free electrons to deteriorate the performance of the detector, the contents of elements such as N, O, and H in the target substance need to be strictly controlled.

At present, high-purity xenon and argon used by a common particle detector adopt a purifier in the semiconductor industry to remove N, O and H, filler materials playing a purifying role mainly comprise zirconium-aluminum alloy, zirconium-vanadium-iron alloy and the like, the working temperature is generally lower than 400 ℃, N, O and H impurities in inert gas react with the filler to produce solid compounds to be solidified, and therefore the gas is purified. However, the purifiers have the defect that the radon release rate of the used filler is high, and the radon release rate of some purifiers is extremely high, so that the radon enters the particle detector along with the circulating gas to cause background rise and deteriorate the performance of the detector. In addition, the existing purifiers are expensive and have low purification rate, and the purification rate of the purifiers is still low for detectors of tens of tons and hundreds of tons in the future.

With the advance of high-energy physical experimental research, the requirement on the purity of a target substance is higher and higher, and the requirement on the background level of a particle detector is more and more strict, so that higher requirements are provided for a purifier, better purification speed and purification effect are required, and the radon release rate is low. And with the enlargement of the experimental scale, the experimental space is more and more strained, so that it is desired that the purifier does not increase in volume while improving the purification performance.

Disclosure of Invention

To solve as aboveThe above problem needs to be solved from two aspects. On one hand, high-purity filler is adopted, optional filler comprises zirconium, hafnium, titanium, vanadium, iron, copper and the like, the materials need to be subjected to vacuum electron beam smelting or electrolytic refining and radioactivity measurement, ²³⁸ U、 ²³² the content of Th is not more than 10mBq/kg to control radon release rate of the purifier. On the other hand, the working temperature of the filler is increased, for example, the working temperature is increased to 800 ℃, the impurity elements and the filler have higher reactivity and speed, and better purification effect can be obtained. However, at such high temperature, it is difficult for the existing flange to satisfy the requirements of high sealing performance, high cleanliness, and convenience in replacement at the same time, so the flange seal also needs to consider the requirement of high-temperature working conditions.

The technical solution of the utility model is as follows:

a high-temperature high-purity inert gas purifier with low radon emissivity is characterized by comprising a heat exchanger, branch pipelines, and an outlet pipeline, a main pipeline and an inlet pipeline which are sequentially connected;

the hot side inlet end of the heat exchanger is connected with the outlet pipeline, and the cold side inlet end of the heat exchanger is used for inputting gas to be purified; the cold side outlet end of the heat exchanger is connected with one end of the branch pipeline, and the other end of the branch pipeline is connected with the inlet pipeline; high-purity metal filler is filled in the main pipeline;

a main heating and insulating layer is sleeved outside the main pipeline, a lower end socket is sleeved outside the inlet pipeline, and an upper end socket is sleeved outside the outlet pipeline;

when the gas to be purified enters the heat exchanger through the cold side inlet end of the heat exchanger and exchanges heat with the purified gas in the heat exchanger, the gas enters the main pipeline after sequentially passing through the branch pipeline and the inlet pipeline through the cold side outlet end of the heat exchanger, is output through the outlet pipeline after being purified, and enters the heat exchanger through the hot side inlet end of the heat exchanger.

An upper end sealing head is sleeved outside the outlet pipeline, a main heating and insulating layer is sleeved outside the main pipeline, and a lower end sealing head is sleeved outside the inlet pipeline; sealing connection structures are arranged between the upper end socket and the top of the main heat insulation layer and between the lower end socket and the bottom of the main heat insulation layer;

the seal head knife edge flange and the upper end seal head or the lower end seal head are formed by welding or integrally machining, the main pipeline knife edge flange and the main pipeline are formed by welding or integrally machining, and the seal head knife edge flange and the main pipeline knife edge flange are fixedly connected in a sealing manner through a fastener and a sealing ring;

the upper end socket and the lower end socket are hollow and are used for an outlet pipeline or an inlet pipeline to pass through to form an inner pipeline, and one end of the inner pipeline, which is close to the end socket knife edge flange, is sleeved with a plurality of flow blocking fins to restrain a flow path of high-temperature gas.

Further, the high-purity metal filler is subjected to vacuum electron beam smelting or electrolytic refining and radioactivity measurement, ²³⁸ U、 ²³² the content of Th is not more than 10mBq/kg.

Preferably, the high purity metal filler is zirconium, hafnium, titanium, vanadium, copper or iron.

Further, the surface temperature of the middle section part of the main pipeline is not lower than 600 ℃ in a working state.

Furthermore, a branch heating and insulating layer is sleeved outside the branch pipeline.

Further, a heat dissipation mechanism is arranged between the end socket knife edge flange and the main pipeline knife edge flange and on the main pipeline, so that the temperature of the end socket knife edge flange and the temperature of the main pipeline knife edge flange are not more than 200 ℃.

Further, the heat dissipation structure is a plurality of air-cooled radiating fins and/or water-cooled jackets.

Preferably, one of the air-cooled fins closest to the midpoint of the main pipe is close to the fixing ring on the inner wall of the main pipe, or if a water-cooled jacket is used, the water-cooled jacket outside the main pipe is close to the fixing ring.

Further, the outer diameter of the flow resisting fin is 3-5 mm smaller than the inner diameter of the jacketed pipe and is used as a flow discharging channel for vacuumizing, or the flow resisting fin is arranged in the jacketed pipe and is provided with a through hole, and the diameter of the through hole is 3-5 mm larger than that of the inner pipeline.

Further, the pipe section part of the jacket pipe is not in contact with the main pipeline and the knife edge flange, and the distance is at least 2mm.

And filter screens or perforated plates are arranged at the fixing rings at the inner side and the lower side of the jacket pipe.

Compared with the prior art, the beneficial effects of the utility model are that:

1) The working temperature of the knife edge flange is ensured, a jacket pipe structure is designed in the main pipeline and the knife edge flange, the distance between the outer wall of a jacket pipe section and the knife edge flange is 5-10 mm, a high-temperature medium can only flow through the inside of the jacket pipe, and gas between the knife edge flange and the jacket does not have forced convection. Because the heat conductivity of the gas is poor, the heat transfer capacity between the natural convection high-purity medium gas and the knife edge flange is also low, and the high-purity medium between the outer wall of the jacket pipe and the knife edge flange has a heat insulation effect substantially, the high-temperature high-purity medium has low heating power on the knife edge flange, and the knife edge flange and the gasket can work at a lower temperature by considering the heat dissipation of the knife edge flange, so that the reliability and the sealing property of the knife edge flange are ensured.

2) The high-purity filler is placed in a high-temperature alloy pipeline, and a heating device and a heat-insulating material are sequentially arranged outside the pipeline, so that the filler is ensured to work at a proper temperature.

3) The medium temperature after the purification is extremely high, leaves the purification filler after, at first with the low temperature of treating the purification, normal atmospheric temperature medium heat exchange, on the one hand the recovery energy reduces the demand to the heating power of admitting air, on the other hand makes the gas cooling of having purified, guarantees safe in utilizationly.

4) The used materials are subjected to radioactivity detection and control and radon release rate detection and control in advance, so that the purified gas is prevented from being polluted by radon.

Drawings

FIG. 1 is a schematic structural view of an embodiment of the low radon emission high temperature high purity inert gas purifier of the present invention

FIG. 2 is the utility model discloses a knife edge flange embodiment 1 structural design drawing suitable for high temperature operating mode

Fig. 3 shows the utility model discloses a knife edge flange embodiment 2 structural design drawing suitable for high temperature operating mode

FIG. 4 is a structural view of the jacket sleeve of the present invention

In the figure: 1-heat exchanger outlet piping; 2-a heat exchanger; 2A-heat exchanger hot side outlet pipe; 2B-heat exchanger hot side inlet conduit; 2C-heat exchanger cold side inlet conduit; 2D-heat exchanger cold side outlet conduit; 3-sealing the upper end; 4-a main pipeline; 5-main heating and insulating layer; 7-sealing the lower end; 8-an inlet duct; 10-branch pipes; 11-branch heating and insulating layer; 13-an outlet duct; 12-high purity metal filler; 21-end socket knife edge flange; 22-a fastener; 23 copper seal rings; 24-a main pipeline knife edge flange; 25-an inner conduit; 26-flow blocking fins; 27-upper jacket sleeve; 28-screws; 29-upper side fixing ring; 30-air cooling fins 31-lower side fixing ring; 32-screens or perforated plates; 33-lower jacket sleeve; 41-pipe section; 42-jacket sleeve flange.

Detailed Description

The following detailed description of the embodiments of the present invention is provided with reference to the accompanying drawings, which should not be construed as limiting the scope of the present invention.

Selecting raw materials, namely selecting metal raw materials with lower radioactivity and cleaning agents by using trace detection equipment such as a high-purity germanium spectrometer, ICP-MS and the like. The radon release rate at room temperature and the radon release rate at high temperature are measured on the inner wall of the related pipeline and the metal filler, the radon release rate is converted into the radon release area, and the radon release rate is not more than 1 mBq/square meter and can be used; of metal fillers ²³⁸ U、 ²³² The background level of Th radioactivity is not more than 10mBq/kg; the high-temperature pipeline for containing the metal filler in normal operation is provided with an outer wall at the heat-insulating layer, and the working temperature is not lower than 600 ℃. The air inlet pipe or the air outlet pipe of the high-temperature pipeline extends into the jacket pipe, and one or more flow blocking fins are arranged between the jacket pipe and the air inlet pipe or the air outlet pipe. The flow resisting fins can be welded on the inner side of the jacket pipe, and the cross section area of the through holes of the flow resisting fins is 1-10 square centimeters larger than that of the air inlet pipe or the air outlet pipe. The flow resisting fins can also be welded at the outer sides of the air inlet pipe and the exhaust pipe, the size of each flow resisting fin is slightly smaller than the inner size of the jacket pipe, and the cross section area of a gap between the flow resisting fins is 1-10 square centimeters.

Example 1

As shown in fig. 1, the outlet pipeline 1 is an outlet of the purified gas, and is connected to a hot-side inlet pipeline 2B of the heat exchanger 2, the heat exchanger 2 is a double-pipe heat exchanger or a plate heat exchanger or a shell-and-tube heat exchanger, the gas inlet 2C is an inlet of the gas to be purified, that is, a cold-side inlet pipeline of the heat exchanger 2, the branch pipeline 10 is a high-temperature gas after the gas to be purified passes through the heat exchanger 2, and the purified gas is cooled after being subjected to sufficient heat exchange with the gas to be purified when leaving the hot-side outlet pipeline of the heat exchanger 2, so that the safety of the device is improved, and the heat energy is effectively utilized. The branch pipe 10 is externally provided with a branch heating and insulating layer 11, and when the temperature of the branch pipe 10 is lower than the rated temperature, the electric heating function is started until the temperature reaches the rated temperature of 800 ℃. The gas to be purified reaches the inlet duct 8 of the main duct 4 through the branch duct 10 and enters the main duct 4. One or more high-purity metal fillers 12 are filled in the main pipeline 4, the fillers comprise high-purity zirconium, hafnium, vanadium, titanium, iron, copper and the like, a main heating and insulating layer 5 is arranged outside the main pipeline 4, the main pipeline 4 is ensured to work at the rated temperature of 800 ℃ through switching on and off an electric heating function, and heat is transferred to the metal fillers 12 inside to obtain the expected reaction temperature. The gas to be purified passes through the gaps between the high-purity metal packing 12, and the high-purity metal adsorbs impurities of N, O, and H in the gas to be purified and reacts to generate a solid compound, thereby purifying the gas. And cooling the purified gas through a pipeline and a heat exchanger, and then, allowing the gas to enter a particle detector. The upper end sealing head 3 seals the upper end space of the main pipeline 4, a pipeline 1 discharges purified gas, the lower end sealing head 7 seals the lower end space of the main pipeline 4, and heated gas to be purified is conveyed to enter through an inlet pipeline 8. After the bolts connecting the upper end seal head 3 and the lower end seal head 7 with the main pipeline 4 are removed, the high-purity metal filler 12 in the high-temperature pipeline can be conveniently assembled, disassembled and replaced.

Fig. 2 is the utility model discloses a knife edge flange embodiment 1 structural design picture suitable for high temperature operating mode, as shown in fig. 2, for trunk line 4, 3 connection structure of upper end head and detail. Upper end head 3 has head edge of a knife flange 21, the utility model discloses a model be CF160, internal diameter 150mm, there is trunk line edge of a knife flange 24 trunk 4 upper end, has copper seal ring 23 between head edge of a knife flange 21 and the trunk line edge of a knife flange 24, and two edge of a knife flanges are connected with fastener 22, realize sealedly. An inner pipeline 25 is arranged in the upper end socket and is a purified gas discharge pipe, a plurality of circular choke fins 26 are arranged at the tail end of the inner pipeline 25, and the inner pipeline 25, the choke fins 26 and the end socket knife edge flange 21 are concentric. The main pipeline 4 outside is close to main pipeline edge of a knife flange 24 department and is had a plurality of air-cooled fin 30 in the 150mm distance from main pipeline edge of a knife flange 24 promptly, and the air-cooled fin also can reserve screw hole, through-hole etc. and be convenient for fixed heat pipe structure or other good conductors of heat to the realization is to the extended design of air-cooling ability, also can design here and press from both sides the cover for the water-cooling, in order to guarantee that main pipeline edge of a knife flange 24 does not receive the high temperature influence of main pipeline 4 middle part position. The air-cooled fins 30 are welded to the main pipe 4 to achieve good heat transfer. An upper fixing ring 29 is welded inside the main pipe 4, a threaded through hole is formed in the upper fixing ring 29, and a flange 42 of the jacket pipe 27 is fixed to the upper fixing ring 29 by screws 28. The upper fixing ring 29 is located at approximately the same height as the outer air-cooling fins 30. The jacket 27 is concentric with the main pipe 4, the knife-edge flange 24, the pipe section of the upper end socket 3, the knife-edge flange 22, the pipe 25 and the flow blocking fin 26 after being installed. The outer diameter of the flow resisting fin 26 is 3-5 mm smaller than the inner diameter of the jacket 27, and the flow resisting fin is used as an effusion channel in the vacuum pumping stage. The pipe section 41 of the jacket pipe 27 is not in direct contact with the main pipe 4, the knife edge flange 22 and the knife edge flange 24, and is spaced by 2 mm-10 mm or more, so as to avoid heat conduction among solids. By the design, the knife-edge flange 22, the knife-edge flange 24 and nearby pipe sections can be prevented from being directly heated by high-temperature flowing purified gas, so that the knife-edge flange 22 and the knife-edge flange 24 of the main pipeline can be ensured to be always within the rated working temperature range of 200 ℃, and the sealing property of the flanges is ensured.

The structure of the lower end sealing head 7 and the structure near the lower end sealing head are the same as the structure of the upper end sealing head 3, so that the heating of high-temperature gas to be purified on the knife edge flange can be avoided, the knife edge flange can be ensured to work within a rated temperature range, and the sealing performance can be ensured. The only difference is that as shown in fig. 3, a screen or perforated plate 32 having the same outer diameter as the flange of the jacketed pipe 33 or slightly smaller than the inner diameter of the main pipe 4 is arranged between the lower fixing ring 31 and the jacketed pipe 33, and the aperture is not larger than 2mm, so as to support the high-purity metal packing 12 within a specified range and ensure the purification process. A screen or perforated plate 32 may also be welded to the lower stationary ring 31 of the main pipe 4.

The main pipeline 4 has a total length of 1m, can be filled with high-purity filler with a position of about 700mm, a diameter of 150mm and an effective space of about 12L, and can be filled with about 40kg of high-purity zirconium with a granularity of 3mm, or 80kg of high-purity hafnium with a granularity of 3mm, or filled with a mixture of zirconium, hafnium, vanadium, titanium and iron particles.

The experiment shows that the utility model utilizes the low-radioactivity high-purity metal such as zirconium, hafnium, iron, vanadium, titanium and the like smelted by the electron beam to react with elements such as nitrogen, hydrogen, oxygen and the like in the high-purity inert gas at the temperature of more than 600 ℃ to generate solid compounds, thereby realizing the purification of the high-purity inert gas. The purification effect on high-purity inert gas is good, the released radon gas is less, and the high-speed and high-purity purification requirements of target substances such as argon, xenon and the like in rare case experiments can be met. And can conveniently change the filler after the filler service life is over. The high-temperature pipeline connecting flange has the advantages that the convenience in replacing the filler can be realized, the sealing performance is ensured, the structure such as the jacket pipe and the flow blocking fin is designed in the connecting flange of the high-temperature pipeline, and the connecting knife edge flange is ensured to work at a lower temperature. The method can meet the requirement of rare case high-energy physical experiments on high-speed purification of a large amount of high-purity inert gases, and also meet the requirement of high-temperature working conditions on high-tightness and high-cleanliness flange connection.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced with equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the scope of the claims of the present invention.

Claims (14)

1. A high-temperature high-purity inert gas purifier with low radon emissivity is characterized by comprising a heat exchanger (2), branch pipelines (10), and an outlet pipeline (1), a main pipeline (4) and an inlet pipeline (8) which are sequentially connected;

the hot side inlet end (2B) of the heat exchanger (2) is connected with the outlet pipeline (1), and the cold side inlet end (2C) of the heat exchanger (2) is used for inputting gas to be purified; a cold side outlet end (2D) of the heat exchanger (2) is connected with one end of the branch pipeline (10), and the other end of the branch pipeline (10) is connected with the inlet pipeline (8); high-purity metal filler (12) is filled in the main pipeline (4);

a main heating and insulating layer (5) is sleeved outside the main pipeline (4), a lower end sealing head (7) is sleeved outside the inlet pipeline (8), and an upper end sealing head (3) is sleeved outside the outlet pipeline (1);

when gas to be purified enters the heat exchanger (2) through the cold side inlet end (2C) of the heat exchanger (2) and exchanges heat with purified gas in the heat exchanger (2), the gas to be purified enters the main pipeline (4) through the cold side outlet end (2D) of the heat exchanger (2) after sequentially passing through the branch pipeline (10) and the inlet pipeline (8), is output through the outlet pipeline (1) after being purified, and enters the heat exchanger (2) through the hot side inlet end (2B) of the heat exchanger (2).

2. The low radon emission high temperature high purity inert gas purifier according to claim 1, wherein the hollow inside of the upper end head (3) is used for the outlet pipe (1) to extend into, and the hollow inside of the lower end head (7) is used for the inlet pipe (8) to extend into, so as to form an inner pipe which is formed by connecting the outlet pipe (1), the main pipe (4) and the inlet pipe (8) from top to bottom, and one end of the inner pipe is sleeved with a plurality of flow blocking fins.

3. The low radon emission high temperature high purity inert gas purifier of claim 1, wherein a seal edge flange and a main pipe edge flange are provided between said upper end seal (3) and the top of the main heating and insulating layer (5) and between the bottom of the main heating and insulating layer (5) and the lower end seal (7).

4. The low radon emission high temperature high purity inert gas purifier of claim 3, wherein said head knife edge flange is welded with said upper end head or lower end head as one body or directly machined and formed from a single material, said main pipe knife edge flange is welded with said main pipe (4) as one body or directly machined and formed from a single material, said head knife edge flange and said main pipe knife edge flange are fixedly and sealingly connected by a fastener and a sealing ring.

5. The low radon emission high temperature high purity inert gas purifier of claim 1, wherein said high purity metal filler is vacuum electron beam smelted or electrorefined and measured for radioactivity, ²³⁸ U、 ²³² the content of Th is not more than 10mBq/kg, and the radon discharge rate of the inner surface is not more than 1 mBq/square meter at the temperature of 25 ℃ of the high-temperature pipeline.

6. The low radon emission high temperature high purity inert gas purifier of claim 5, wherein the high purity metal filler is zirconium, hafnium, titanium, vanadium, copper or iron.

7. The low radon emission high temperature high purity inert gas purifier according to claim 1, wherein the branch pipe (10) is externally sleeved with a branch heating and insulating layer (11).

8. The low radon emission high temperature high purity inert gas purifier according to claim 3 or 4, wherein heat dissipation structures are further arranged between the head knife-edge flange and the main pipe knife-edge flange, outside the head knife-edge flanges (21) at both ends of the main pipe (4) and outside the main pipe knife-edge flange (24), so that the temperature of the head knife-edge flange and the main pipe knife-edge flange is not more than 200 ℃.

9. The low radon emission high temperature high purity inert gas purifier of claim 8, wherein said heat dissipating structure is a plurality of air cooled fins and/or water cooled jackets.

10. The low radon emission high temperature high purity inert gas purifier of claim 9, wherein a piece of said air cooling fin closest to the midpoint of said main conduit is within 10cm of the fixed ring position of the inner wall.

11. The low radon emission high temperature high purity inert gas purifier of claim 9, wherein said water cooling jackets are located between said main pipe main heating and insulating layer (5), said seal head knife-edge flange (21) and between said main heating and insulating layer (5) and said main pipe knife-edge flange (24).

12. The low radon emission high temperature high purity inert gas purifier of claim 2, wherein the outer diameter of said flow blocking fins (26) is 3-5 mm smaller than the inner diameter of the jacketed pipe; or the flow resisting fins (26) are welded to the inner side of the jacket sleeve (27), and the diameter of the inner hole of each flow resisting fin (26) is 3-5 mm larger than that of the inner pipe (25); as an evacuation flow channel.

13. The low radon emission high temperature high purity inert gas purifier of claim 3 further comprising a jacketed pipe, an upper retaining ring and/or a lower retaining ring disposed within said main pipe; the solid fixed ring of upside and the solid fixed ring of downside be welded fastening respectively in trunk line inner wall top and below, and inside is equipped with the screw through-hole, make flange (42) of jacket pipe (27) can pass through the screw with the solid fixed ring of upside and/or the solid fixed ring of downside are fixed, and ensure the pipeline section (41) of jacket pipe (27) with trunk line edge of a knife flange is at least apart more than 2mm.

14. The low radon emission high temperature high purity inert gas purifier of claim 13 wherein said underside retainer ring has a screen or perforated plate.

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