Aerosol filter element and aerosol filter

Abstract

The aerosol filter element comprises a filter element body and a sealing gasket, the filter element body is installed on the top face of an element base of an aerosol filter, the filter element body is of a vertically-arranged cylindrical structure, the top end of the filter element body is closed, the surface of the bottom end of the filter element body serves as a butt joint face in butt joint with the element base, and an opening is formed in the surface of the bottom end of the filter element body and serves as a tail gas inlet; the sealing gasket is arranged between the surface of the bottom end of the filter element body and the core seat and is pressed on the core seat by the filter element body, and the sealing gasket is annular and is arranged around the tail gas inlet, so that radioactive tail gas enters the cylindrical structure from the tail gas inlet in the bottom end and is transited through a central cavity in the cylindrical structure; and after being filtered by the side wall serving as the filtering area, the tail gas flows out of the aerosol filter element by taking the outer surface of the cylindrical structure as a tail gas outlet. The filter element disclosed by the invention is reasonable in structural arrangement, higher in gas treatment amount and stronger in sealing connection performance. The invention also provides an aerosol filter.

Description

Technical Field

[0001] The invention specifically relates to an aerosol filter element and an aerosol filter. Background Art

[0002] During the production process of nuclear fuel reprocessing plants, a large amount of radioactive tail gas is generated. These tail gases contain radioactive droplets and aerosols, which are highly corrosive and radioactive. They cannot be discharged directly into the environment and need to be purified. Process tail gas containing radioactive aerosols is usually treated with aerosol filters.

[0003] In the existing technology, due to the limited size of the aerosol filter element maintenance container, there are relatively strict restrictions on the external dimensions of the filter element. At present, the gas volume processed by a single aerosol filter is relatively low, and even the exhaust gas purification system needs to be split and set in parallel because the gas volume does not meet the requirements. This brings inconvenience to the system setting, equipment quantity and investment, equipment room space requirements, personnel inspection and maintenance operation frequency, etc., and has poor economic efficiency. It also does not meet the principle of "as low as reasonably achievable" in the radiation protection optimization method. In addition, due to the resistance of the aerosol filter, multiple filters connected in series lead to a large pressure on the rear exhaust gas transportation. It is particularly important and urgent to further increase the gas volume processed by a single aerosol filter. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an aerosol filter element for the above-mentioned deficiencies in the prior art, the filter element has a reasonable structure, a higher gas processing volume, and a stronger sealing connection performance. The present invention also provides an aerosol filter.

[0005] The present invention provides an aerosol filter element, comprising a filter element body and a sealing gasket. The filter element body is installed on the top surface of a core seat of the aerosol filter. The filter element body is a vertically arranged cylindrical structure with a closed top end and a bottom end surface serving as a docking surface with the core seat. An opening is provided on the bottom end surface to serve as an exhaust gas inlet for docking with an air inlet hole provided on the core seat. The sealing gasket is arranged between the bottom end surface of the filter element body and the core seat and is pressed against the core seat by the filter element body. The sealing gasket is annular and is arranged around the exhaust gas inlet so that the radioactive exhaust gas enters the interior of the cylindrical structure from the exhaust gas inlet at the bottom, transitions through the central cavity in the cylindrical structure, and then is filtered by the side wall serving as a filtering area, and then flows out of the aerosol filter element with the outer surface of the cylindrical structure serving as an exhaust gas outlet.

[0006] Furthermore, the filter element body includes end caps and filter material, the filter material is a cylindrical structure with openings at both ends, the end caps are connected to the two ends of the filter material, and the end cap at the top seals the opening of the filter material, the end cap at the bottom serves as a docking surface, a sealing gasket is arranged on the surface, and an exhaust gas inlet is opened to allow the radioactive exhaust gas to enter the filter material through the exhaust gas inlet for filtration.

[0007] Furthermore, the filter material is formed by folding filter paper with a filtration area of ​​15 m2 to 30 m2 into a cylindrical structure with two ends open, and the number of folds is 500 to 1000.

[0008] Furthermore, the filter element body also includes a protective net, which covers the outer surface and the inner surface of the filter material. The opening structure on the protective net is circular or diamond-shaped, and the opening rate of the protective net is 7% to 15.74%.

[0009] Furthermore, within the range of radioactive tail gas inlet volume of 200m3 / h to 1000m3 / h, the filtration resistance of the aerosol filter element is not higher than 250Pa.

[0010] Furthermore, the cross-sectional area of ​​the filter element body is 0.071 m2 to 0.229 m2, and the tail gas inlet cross-sectional area accounts for 16% to 37.35% of the cross-sectional area of ​​the filter element body.

[0011] Furthermore, the aerosol filter element also includes a detection component, and an avoidance area is provided at the annular center line of the sealing gasket, so that when the bottom end surface of the filter element body and the top surface of the core seat are fitted and connected, the sealing gasket seals to form an annular sealing cavity surrounding the joint between the exhaust gas inlet and the air inlet hole. The detection component is connected to the annular sealing cavity to obtain the sealing condition of the annular sealing cavity, and to determine whether the aerosol filter element is installed in place based on the sealing condition.

[0012] Furthermore, the sealing gasket includes two annular sealing channels, one sealing channel surrounds the periphery of the other sealing channel, so that the area between the two sealing channels forms the avoidance area. When the bottom surface of the filter element body and the top surface of the core seat are fitted and connected, the bottom surface of the filter element body, the top surface of the core seat and the two sealing channels close the avoidance area in the middle, so that the avoidance area forms an annular sealing cavity surrounding the joint between the exhaust gas inlet and the air inlet hole.

[0013] Furthermore, the detection component includes a connecting pipeline, a compressed gas supply device and a pressure measuring unit. The connecting pipeline is connected between the annular sealing chamber and the compressed gas supply device, and is used to input the compressed gas supplied by the compressed gas supply device into the annular sealing chamber so that the air pressure in the annular sealing chamber reaches a set pressure. The detection end of the pressure measuring unit is connected to the connecting pipeline, which is used to obtain the pressure conditions in the annular sealing chamber through the connecting pipeline, and to determine that the aerosol filter element is installed in place when the pressure drop in the annular sealing chamber is less than a set value within a set time.

[0014] The present invention also provides an aerosol filter, comprising a shell and the above-mentioned aerosol filter element, wherein an air inlet and an air outlet are provided on the wall surface of the shell, a core seat is provided in the inner cavity between the air inlet and the air outlet, and an air inlet hole is provided on the core seat, and the aerosol filter element is accommodated in the inner cavity of the shell and installed on the top surface of the core seat so that the exhaust inlet is connected to the air inlet hole.

[0015] Furthermore, the air inlet, core seat and air outlet are arranged in sequence from bottom to top, the inner cavity of the shell is in the shape of a vertically arranged cylinder, the air inlet is in the shape of a horizontally arranged tube, and the air inlet is arranged along the tangent direction of the shell, so that the radioactive exhaust gas enters the aerosol filter element through the air inlet hole along the inner cavity wall of the shell in a spiral streamline.

[0016] Furthermore, a guide tube is provided on the bottom side of the core seat, the top opening of the guide tube is connected to the air inlet, and the bottom opening is lower than the air inlet. The radioactive exhaust gas reaches the bottom opening of the guide tube along the inner wall of the shell in a spiral streamline and then enters the aerosol filter element through the air inlet.

[0017] The aerosol filter element of the present invention arranges the exhaust gas inlet on the bottom surface. Compared with the current conventional filter element adopts the structure of top air intake and side air outlet, firstly, the filter element body can be installed on the top surface of the core seat. The core seat itself can not only serve as the setting surface of the air inlet hole, but also support the filter element body from the bottom, providing good support force for the filter element; further, the sealing gasket can not only be connected by fasteners and other connection forms, but also be pressed against the core seat by the gravity of the filter element body itself, and the sealing performance will not be reduced due to the falling of the filter element body as the use time increases.

[0018] More importantly, in the filter element body of this embodiment, the combination of the three factors of the opening being arranged at the bottom, the cylindrical structure, and the sealing gasket can also play a beneficial role in optimizing the airflow direction, increasing the gas volume processed by a single filter element, and improving the sealing performance. Specifically, if the filter element body adopts a monolithic structure without a central cavity, then when a sealing gasket with good sealing performance (wider sealing area) is used, it will block the flow of exhaust gas, not only losing part of the air intake area, but also causing disturbances to the gas flow field, that is, the exhaust gas will not flow through the area near the sealing gasket, and the equipment resistance will be further increased. If you want to avoid the influence of the airflow dead zone, the filter element filling area needs to be raised and moved up to the area where the airflow is evenly mixed, that is to say, there is also a certain loss or waste in the bed height. That is, if the original filter element filling structure is used, in order to achieve a good seal, the air intake area will be reduced and the flow rate will increase. In order to achieve the same adsorption effect, more filter materials are required, and the equipment resistance is also increased. In addition, useless areas appear in the height direction, wasting space.

[0019] The present embodiment adopts a cylindrical structure combined with a bottom opening. The cylindrical structure itself can optimize the direction of the airflow and make full use of the longitudinal space. After the exhaust gas enters the central cavity, a part of it will be filtered and flowed out from the area close to the sealing pad under the action of gravity. The exhaust gas flow as a whole is basically filtered uniformly by the filter element in the longitudinal direction. Therefore, under the premise of ensuring a certain filter bed height, the effective filtration volume is larger, and the filter element processing capacity is significantly improved under the same gas velocity conditions. Moreover, since the width of the sealing pad will not cause exhaust gas disturbance, a more sealed sealing pad can be used to enhance the sealing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the internal structure of the aerosol filter element in Example 1 of the present invention;

[0021] Figure 2 is a schematic cross-sectional structure diagram of an aerosol filter element in Example 1 of the present invention;

[0022] Figure 3 Schematic diagram of the overall structure of the aerosol filter element in Example 1 of the present invention;

[0023] Figure 4 is an enlarged view of the sealing gasket structure of the aerosol filter element in Example 1 of the present invention;

[0024] Figure 5 Schematic diagram of the detachable suspension rod structure of the aerosol filter element in Example 1 of the present invention;

[0025] Figure 6 is a schematic structural diagram of an aerosol filter in Example 2 of the present invention;

[0026] Figure 7 is a schematic diagram of the top view of the aerosol filter in Example 2 of the present invention;

[0027] Figure 8 Schematic diagram of another structure of the aerosol filter in Example 2 of the present invention.

[0028] Fig. 9 It is a schematic diagram of the structure of an existing conventional aerosol filter;

[0029] Fig.10 It is a schematic diagram of the top view structure of an existing conventional aerosol filter.

[0030] In the figure: 1. exhaust gas inlet; 2. sealing gasket; 21. annular sealing chamber; 22. sealing channel; 3. detection part; 31. connecting pipeline; 4. air inlet; 5. end cover; 51. lower section; 52. upper section; 53. support rod; 6. filter material; 7. protective net; 8. shell; 81. air inlet; 82. air outlet; 83. core seat; 831. guide tube. DETAILED DESCRIPTION

[0031] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of the present invention.

[0032] In the description of the present invention, it should be noted that the terms "upper", "lower" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience and simplification of the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the present invention.

[0033] In the description of the present invention, the terms “first”, “second” and “third” are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0034] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connect", "set", "install", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0035] Example 1

[0036] like Figures 1 to 8 As shown, the aerosol filter element of the present embodiment includes a filter element body and a sealing gasket 2. The filter element body is installed on the top surface of the core seat 83 of the aerosol filter. The filter element body is a vertically arranged cylindrical structure with a closed top end and a bottom end surface serving as a docking surface with the core seat 83. An opening is provided on the bottom end surface to serve as an exhaust gas inlet 1 for docking with the air inlet 4 provided on the core seat 83. The sealing gasket 2 is padded between the bottom end surface of the filter element body and the core seat 83 and is pressed against the core seat 83 by the filter element body. The sealing gasket 2 is annular and is arranged around the exhaust gas inlet 1 so that the radioactive exhaust gas enters the interior of the cylindrical structure from the exhaust gas inlet 1 at the bottom, transitions through the central cavity in the cylindrical structure, and then is filtered by the side wall serving as the filtering area, and then flows out of the aerosol filter element with the outer surface of the cylindrical structure serving as the exhaust gas outlet.

[0037] The aerosol filter element of the present embodiment sets the exhaust inlet 1 on the bottom surface. Compared with the current conventional filter element adopting the structure of top air intake and side air outlet, firstly, the filter element body can be installed on the top surface of the core seat 83. The core seat 83 itself can not only serve as the setting surface of the air inlet 4, but also support the filter element body from the bottom, providing good support for the filter element; further, the sealing gasket 2 can not only be connected by fasteners and other connection forms, but also be pressed against the core seat 83 by the gravity of the filter element body itself, and the sealing performance will not be reduced due to the falling of the filter element body as the use time increases.

[0038] More importantly, in the filter element body of this embodiment, the combination of the three factors of the opening being arranged at the bottom, the cylindrical structure, and the sealing gasket can also play a beneficial role in optimizing the airflow direction, increasing the gas volume processed by a single filter element, and improving the sealing performance. Specifically, if the filter element body adopts a monolithic structure without a central cavity, then when a sealing gasket with good sealing performance (wider sealing area) is used, it will block the flow of exhaust gas, not only losing part of the air intake area, but also causing disturbances to the gas flow field, that is, the exhaust gas will not flow through the area near the sealing gasket, and the equipment resistance will be further increased. If you want to avoid the influence of the airflow dead zone, the filter element filling area needs to be raised and moved up to the area where the airflow is evenly mixed, that is to say, there is also a certain loss or waste in the bed height. That is, if the original filter element filling structure is used, in order to achieve a good seal, the air intake area will be reduced and the flow rate will increase. In order to achieve the same adsorption effect, more filter materials are required, and the equipment resistance is also increased. In addition, useless areas appear in the height direction, wasting space.

[0039] The present embodiment adopts a cylindrical structure combined with a bottom opening. The cylindrical structure itself can optimize the direction of the airflow and make full use of the longitudinal space. After the exhaust gas enters the central cavity from bottom to top, a part of it will be filtered and flowed out from the area close to the sealing pad under the action of gravity. The exhaust gas flow as a whole is basically filtered uniformly by the filter element in the longitudinal direction. Therefore, under the premise of ensuring a certain filter bed height, the effective filtration volume is larger, and the filter element processing capacity is significantly improved under the same gas velocity conditions. Moreover, since the width of the sealing pad will not cause exhaust disturbance, a more sealed sealing pad can be used to enhance the sealing performance.

[0040] In this embodiment, the filter element body includes an end cap 5 and a filter material 6. The filter material 6 is a cylindrical structure with openings at both ends. The end cap 5 is connected to both ends of the filter material 6, and the end cap 5 at the top closes the opening of the filter material 6. The end cap 5 at the bottom serves as a docking surface, and a sealing gasket 2 is arranged on the surface, and a tail gas inlet 1 is provided, so that the radioactive tail gas enters the filter material 6 through the tail gas inlet 1 for filtration. The end cap 5 makes the structure of the filter element more regular, provides a flat docking surface for the docking of the tail gas inlet 1 and the air inlet 4, and also provides a flat setting surface for the sealing gasket 2. The filter material 6 with a cylindrical structure forms a central cavity in the middle, and the tail gas enters the central cavity through the tail gas inlet 1, so that the tail gas will be filtered from the filter material 6 as the side wall, which optimizes the airflow direction. This structural type can make full use of the longitudinal space of the filter element, and the filtration area is larger under the premise of ensuring a certain filter bed height, and the filter processing capacity is significantly improved under the same gas velocity conditions.

[0041] In this embodiment, Figure 5 As shown, the filter element is a vertical cylindrical structure, the lower end cover 5 is provided with an exhaust gas inlet 1, and the upper end cover 5 is provided with a detachable suspension rod, which is divided into two parts: a lower section 51 and an upper section 52. The lower section 51 is shorter, the bottom end is connected to the upper end cover 5, and a threaded hole is processed on the top; the upper section 52 is processed with an external thread at the bottom, an inner hexagon (countersunk hole) is processed at the top, and a flat mouth is processed in the middle section, which is convenient for clamping by a robot, etc., so as to lift and replace the filter element. When the suspension rod is disassembled, the upper section 52 is unscrewed from the filter element from the inner hexagon at the top using the power tool of the robot, so that the filter element can be put into use.

[0042] In this embodiment, the upper and lower end caps 5 of the filter element body can be connected by a vertical support rod 53 (located in the central cavity of the core body, with the top end connected to the bottom surface of the upper end cap 5 and the bottom end connected to the edge of the tail gas inlet 1 of the lower end cap 5), so as to support, fix and connect the end surface and fix the pleated filter paper. The number can be three, and there is no specific requirement.

[0043] In this embodiment, the filter material 6 is a filter paper with a filtration area of ​​15㎡ to 30㎡ folded into a cylindrical structure with two ends open, and the number of folds is 500 to 1000. The filter paper folding can increase the filtration area, and achieve a stronger filtration capacity while the overall volume of the filter element is as small as possible, thereby improving the overall filtration efficiency. At the same time, the 6 folds of the filter material formed after folding can guide the air flow, making the air flow smoother, thereby reducing noise and energy consumption, so that the processed gas volume can meet the requirements. And within the range of 500 to 1000 pleats, the resistance is basically small. When the number of folds is too high, the resistance will increase. The resistance of the filter element shows a trend of first decreasing and then increasing with the increase of the number of pleats.

[0044] In this embodiment, the filter element body also includes a protective net 7, which covers the outer surface and the inner surface of the filter material 6. The opening structure on the protective net 7 is circular or diamond-shaped (the layout of each opening can be arranged in an equilateral triangle). The opening rate of the protective net 7 is 7% to 15.74%. The protective net 7 can not only maintain the overall structure of the filter material 6, but also avoid blocking the outflow of exhaust gas. The opening rate range of 7% to 15.74% can not only ensure that the resistance of the filter is small, but also ensure that the structural support of the pleated filter paper of the filter element is firm. The higher the opening rate, the smaller the resistance of the filter. When the opening rate is too high, the structural support becomes poor and the filter paper is easily damaged.

[0045] In this embodiment, within the range of 200 m3 / h to 1000 m3 / h of the radioactive tail gas inlet volume, the filtration resistance of the aerosol filter element is not higher than 250 Pa. This relationship between the volume and the resistance can meet the processing requirements for the aerosol filter.

[0046] In this embodiment, the cross-sectional area of ​​the filter element body is 0.071㎡~0.229㎡, and the cross-sectional area of ​​the tail gas inlet 1 accounts for 16%~37.35% of the cross-sectional area of ​​the filter element body. This proportion relationship not only makes the tail gas inlet 1 of moderate size and the air intake volume meet the requirements, but also makes the thickness of the filter material 6 in the filter element moderate, which is neither too thin to meet the treatment effect nor too thick to cause the size to be too large. The cross-sectional area of ​​the filter element body matches the size of current industrial applications. If the proportion of the cross-sectional area of ​​the tail gas inlet 1 is too small, the gas velocity will be too high when the same tail gas enters the filter element, which will damage the filter paper. If the proportion of the cross-sectional area of ​​the tail gas inlet is too large, the space left for the pleated filter paper will become smaller, and the filtering resistance of the entire filter element will increase.

[0047] The aerosol filter element of the present embodiment also includes a detection component 3. An avoidance area is provided at the annular center line of the sealing gasket 2, so that when the bottom surface of the filter element body and the top surface of the core seat 83 are fitted and connected, the sealing gasket 2 is sealed to form an annular sealing cavity 21 surrounding the joint between the exhaust gas inlet 1 and the air inlet hole 4. The detection component 3 is connected to the annular sealing cavity 21 to obtain the sealing condition of the annular sealing cavity 21, and to determine whether the aerosol filter element is installed in place according to the sealing condition.

[0048] The reason for setting up this detection structure scheme is that in the prior art, the filter element can only be tested for efficiency in the initial installation stage (i.e., the stage without contamination of radioactivity), and cannot be effectively tested after the filter element is replaced later. This is because the current detection means are generally: obtaining the radioactivity in the inlet and outlet airflow for comparison to obtain the efficiency test results. Therefore, when the installation is completed, the body of the device has not been contaminated, and accurate radioactivity detection can be performed. However, once it is put into use, the body of the device is contaminated, and the obtained airflow radioactivity detection results will be affected by interference, and it is difficult to obtain effective results. In this case, if the filter element is not installed in place during the later replacement, it will cause the airflow to short-circuit (i.e., output without filtering), and it is difficult to detect this situation in time because the detection means are immature, which may eventually lead to more serious pollution leakage. In the nuclear fuel reprocessing plant that has been in operation, there has been an airflow short-circuit caused by the iodine adsorber or filter not being installed in place, and the radioactive tail gas was directly sent to the chimney for discharge without effective treatment, which caused pollution to the atmospheric environment.

[0049] The filter element of this embodiment is provided with an annular sealing gasket 2 at the periphery of the exhaust gas inlet 1, and by setting an avoidance area, when the aerosol filter element is connected with the inner cavity of the aerosol filter, the two fitting surfaces to be sealed form an annular sealing cavity 21 sealed by the sealing gasket 2 itself after fitting. Therefore, the sealing condition in the sealing cavity can be directly related to whether the sealing gasket 2 is in good contact with the core seat 83.

[0050] Compared with the conventional simple sealing form, this sealing form not only has higher sealing strength, but also the sealing cavity structure can be tested for air tightness, which greatly improves the efficiency of filter failure diagnosis. Specifically, only when all circumferential positions of the docking position are strictly fitted, the annular sealing cavity 21 as a whole has a good sealing condition. In this case, after the radioactive gas flows out from the air inlet 4, it all flows into the exhaust gas inlet 1, and all flows out after being filtered by the filter element, and no gas short circuit will occur. Therefore, this embodiment sets a specific annular sealing cavity 21 structure, and can determine whether the filter element is installed in place by detecting the sealing cavity condition, which can not only improve the sealing strength, but also provide setting conditions for airflow short circuit detection, ensuring that the filter element is 100% devoted to the filtering work, effectively avoiding airflow short circuit, and avoiding pollution leakage.

[0051] The filter element of the present embodiment adopts a cylindrical structure. The cylindrical structure itself can optimize the direction of airflow and make full use of the longitudinal space. Under the premise of ensuring a certain adsorbent bed height, the adsorption area is larger, and the filtering processing capacity is significantly improved under the same gas velocity conditions. Even if the aforementioned sealing gasket structure is adopted, it will not lead to a reduction in the air intake area, an increase in flow rate and a waste of space. Therefore, the present filter element can adopt the aforementioned sealing gasket structure with better effect, so that the filter element has a better sealing effect and can perform airflow short-circuit detection. At the same time, due to the optimized structural type, the filter space can be fully utilized, and the filter processing capacity can be increased while ensuring the resistance and aerosol filtration efficiency.

[0052] In this embodiment, the sealing gasket 2 is arranged on the bottom surface of the filter element body, and the sealing gasket 2 includes two annular sealing channels 22, and one sealing channel 22 surrounds the periphery of the other sealing channel 22, so that the area between the two sealing channels 22 forms an escape area. When the bottom surface of the filter element body and the top surface of the core seat 83 are fitted and connected, the bottom surface of the filter element body, the top surface of the core seat 83 and the two sealing channels 22 close the escape area in the middle, so that the escape area forms an annular sealing cavity 21 surrounding the joint between the exhaust gas inlet 1 and the air inlet 4.

[0053] This arrangement not only provides two-level sealing measures to further improve the sealing performance, but also cleverly forms a sealing cavity 21 structure. The sealing cavity 21 itself can serve as an airtight sealing cavity, and its sealing condition also provides a means of detecting whether an airflow short circuit occurs. The size of the two sealing paths 22 can be selected according to the size of the filter element combined with the processing accuracy of the sealing gasket 2, and can be located below the filling area of ​​the filter material 6 of the ring-shaped filter element, so as to ensure that the airflow does not short-circuit and maximize the air path channel with the minimum resistance.

[0054] In this embodiment, the detection component 3 includes a connecting pipeline 31, a compressed gas supply device and a pressure measuring unit. The connecting pipeline 31 is connected between the annular sealing chamber 21 and the compressed gas supply device, and is used to input the compressed gas supplied by the compressed gas supply device into the annular sealing chamber 21 so that the air pressure in the annular sealing chamber 21 reaches a set pressure. The detection end of the pressure measuring unit is connected to the connecting pipeline 31, and is used to obtain the pressure conditions in the annular sealing chamber 21 through the connecting pipeline 31, and to determine that the aerosol filter element is installed in place when the pressure drop in the annular sealing chamber 21 is less than a set value within a set time.

[0055] Specifically, Figure 4As shown, the end opening of the connecting pipeline 31 is provided on the core seat 83, and is located at a position corresponding to the avoidance area on the sealing gasket 2, so that after the bottom surface of the filter element body and the top surface of the core seat 83 are attached, the annular sealing cavity 21 is connected. The compressed gas supply equipment and the pressure measuring unit (not shown in the figure, and conventional equipment on the market can be used) can be arranged outside the equipment room where the aerosol filter is located (reducing the impact of radiation protection, and a position where personnel can operate), and the pipe body of the connecting pipeline 31 can be extended outside the equipment room, and then connected to the compressed gas supply equipment and the pressure measuring unit, so as to facilitate personnel operation and observation.

[0056] The compressed gas supply device can supply compressed air, and after the filter element is installed or replaced, an air tightness test is performed. The test pressure during the test is 0.03Mpa (i.e., the set pressure in the annular sealing chamber 21 reaches 30kPa (g)), and the pressure is maintained for 10 minutes without leakage (i.e., the set time is 10 minutes, the pressure drop setting value is 1kPa, i.e., the pressure drop is <0.001Mpa (1kPa)), which is qualified, and the filter element is judged to be installed in place.

[0057] The connecting pipeline 31 can be formed by one pipeline or multiple pipelines connected in series. In the present embodiment, the pressure measuring unit pipeline and the aerosol filter branch (connected to the annular sealing chamber 21) are connected in series to form the connecting pipeline 31, wherein the pressure measuring unit adopts a mobile pressure measuring device. In the connecting pipeline 31, a first valve is provided at the bottom of the pressure measuring unit, and a second valve is provided on the aerosol filter branch. A pressure relief valve may also be provided on the connecting pipeline 31.

[0058] ① Before replacing the filter element, first test the sealing of the connecting pipe 31 and each valve:

[0059] Open the first valve under the mobile pressure measuring device, adjust the pressure in the connecting pipeline 31 to 30 kPa (g). If the pressure is too high at this time, open the pressure relief valve to release the pressure, and close the pressure relief valve after the pressure is released; then open the second valve on the branch of the aerosol filter to be tested, and adjust the pressure in the connecting pipeline 31 again to keep it at 30 kPa (g), wait for 10 minutes, if the pressure drop is less than 1 kPa, it means that the connecting pipeline 31 has good sealing performance; then open the pressure relief valve, release the pressure in the connecting pipeline 31, and then close the pressure relief valve, the second valve on the branch, and the first valve under the mobile pressure measuring device in sequence;

[0060] After replacing the aerosol filter element, an air tightness test is required:

[0061] ② First, open the first valve under the mobile pressure measuring device, adjust the pressure in the connecting pipe 31 to 30 kPa (g), and wait for 10 minutes. At this time, the pressure drop should be less than 1 kPa;

[0062] ③ Open the second valve on the branch of the aerosol filter to be tested, adjust the pipeline pressure to 30kPa (g), wait for about 5 minutes after the pressure stabilizes, and close the first valve under the mobile pressure measuring device. After 10 minutes, if the pipeline pressure is still maintained at 29kPa (g) or above, it is considered that the sealing test has passed; then open the pressure relief valve, and when the pressure in the connecting pipeline 31 is displayed as 0, close the pressure relief valve and the second valve on the branch in turn. The sealing test is over.

[0063] The aerosol filter element of this embodiment can be used in the field of nuclear fuel post-processing, and specifically can be used for filtering and adsorbing process exhaust gas containing radioactive aerosols, and can be used for an aerosol filter including the aerosol filter element.

[0064] The filter element is a cylindrical structure, the inner and outer layers of the cylinder are protected by a metal mesh protective net 7, an aerosol filter material is folded in the middle, a support rod 53 is provided in the middle of the filter element to support the end caps 5 of the upper and lower bottom surfaces, and a double-layer sealing ring is provided on the bottom surface. The aerosol filter element has an optimized structural type, which can make full use of the horizontal and vertical space in the shell, and has a larger filtering area while ensuring a high level of aerosol filtration efficiency, and significantly improves the aerosol filter processing capacity under the same gas velocity conditions.

[0065] The sealing structure of the aerosol filter element is also optimized. A sealing ring is added at the contact point between the filter element and the shell, and it is optimized to a double-layer sealing ring structure to facilitate sealing detection after replacing the filter element, to prevent the problem of airflow short circuit caused by the lack of compression between the filter element and the core seat 83. A sealing detection air pipe (connecting pipeline 31) is inserted between the two layers of sealing rings, and a pressure holding test is performed after each filter element replacement. The gas enters from the bottom of the filter element, and is discharged from all sides of the filter element after the aerosol is removed by the aerosol filter material. The bottom of the aerosol filter is sealed by contacting with the sealing pad 2 of the filter element, and the upper part is sealed by gravity compression. In addition, the provided sealing ring structure can be tested for air tightness, which greatly improves the efficiency of filter failure diagnosis.

[0066] Specifically, the filter element structure includes two end covers 5, namely an upper end cover 5 and a lower end cover 5 (the lower end cover 5 is an end cover 5 provided with an exhaust gas inlet 1 and a sealing gasket 2), and the space between the two end covers 5 is used as a filter material 6 filling area (including a protective net 7), and also includes a double-pass sealing gasket 2. The filter material 6 filling area is a cylindrical structure, and the airflow enters from the middle cavity at the top or bottom (the bottom in this embodiment) of the filter element, and is discharged from the cylinder wall around the cylinder after the aerosol is filtered by the filter paper of the filter material 6. The double-pass sealing gasket 21 can be used for air tightness testing of the aerosol filter element after installation to avoid the occurrence of airflow short circuit. It is used to confirm that the aerosol filter element is installed in place, the seal is good, there is no risk of air path short circuit, and the operation safety is improved. The aerosol filter element of this structure has a filtration efficiency of not less than 99.99% for various aerosol molecules of 0.1μm and above.

[0067] Example 2

[0068] The aerosol filter of this embodiment is used for filtering aerosols in radioactive tail gas and can be installed below the building surface, such as Figures 6 to 8 As shown, the filter includes a shell 8 and the aerosol filter element in Example 1, an air inlet 81 and an air outlet 82 are provided on the wall of the shell 8, a core seat 83 is provided in the inner cavity between the air inlet 81 and the air outlet 82, an air inlet hole 4 is provided on the core seat 83, the aerosol filter element is accommodated in the inner cavity of the shell 8, and is installed on the top surface of the core seat 83 so that the exhaust inlet 1 is connected to the air inlet 4.

[0069] The aerosol filter of this embodiment can significantly improve the processing capacity of a single device by using the aerosol filter element in Example 1, and has an optimization effect on the system setting of the process tail gas purification system of the nuclear fuel reprocessing plant, the number of equipment and equipment investment, the space requirements of the equipment room, the frequency of personnel inspection and maintenance operations, etc., significantly improves the economic efficiency, and is conducive to the optimization management of radiation protection. In the later stage of operation, after the filter element is replaced, an air tightness test can be performed to ensure that the aerosol filter element is installed in place and there is no airflow short circuit problem, which further improves safety and reduces the risk of tail gas being discharged into the environment without radioactive purification treatment.

[0070] In this embodiment, the air inlet 81, the core seat 83 and the air outlet 82 are arranged in sequence from bottom to top, so that the radioactive tail gas passes through the air inlet 81, the core seat 83, the aerosol filter element and the air outlet 82 in sequence during the rising process in the shell 8. In the inner cavity of the shell 8, a cavity as a buffer space is provided in the area between the air inlet 81 and the core seat 83, so that the radioactive tail gas first reaches the cavity after entering the air inlet 81 and then enters the aerosol filter element through the air inlet hole 4.

[0071] Compared with the traditional direct current intake method (such as Fig. 9 and Fig.10 In this embodiment, the inner cavity of the shell 8 is in the shape of a vertically arranged cylinder, the air inlet 81 is in the shape of a horizontally arranged cylinder, and the air inlet 81 is arranged along the tangential direction of the shell 8 (located at the bottom of the inner cavity of the shell 8), as shown in FIG. Figure 6 and Figure 7 As shown, the radioactive tail gas enters the aerosol filter element through the air inlet 4 along the inner wall of the shell 8 in a spiral streamline. Through the collision of the rotating airflow and the shell 8, the tail gas is demisted while ensuring the filtration resistance, reducing the moisture content, thereby preventing the filter material 6 from being affected by a large number of droplets, ensuring the filtration efficiency, reducing the filtration resistance, and extending the service life of the filter material 6, further reducing the replacement frequency of the filter element.

[0072] In this embodiment, a guide tube 831 may be provided. Figure 8As shown, specifically, a guide tube 831 is provided on the bottom side of the core seat 83, the top opening of the guide tube 831 is connected to the air inlet 4, and the bottom opening is lower than the air inlet 81 (the air inlet 81 is located at the bottom of the core seat 83, which is slightly higher than the position of the air inlet 81 in the method without the guide tube 831). The radioactive tail gas reaches the bottom opening of the guide tube 831 along the inner wall of the shell 8 in a spiral streamline and then enters the aerosol filter element through the air inlet 4. This setting can further extend the flow line of the radioactive tail gas, thereby further optimizing the effect of reducing the moisture content.

[0073] Specifically, the air inlet 81 is set at the tangential position of the shell 8, and the position of the air inlet 81 is moved up as close to the filter element as possible. At the same time, a cylindrical wind shield guide plate (guide tube 831) is set on the lower side of the filter element sealing plate (i.e., the core seat 83), so that after the airflow enters the shell 8 along the tangential direction, it first rotates downward along the wall of the shell 8, and then enters the air inlet of the filter element upward at the end of the cylindrical wind shield guide plate.

[0074] In general, the aerosol filter of this embodiment includes a housing 8 and an aerosol filter element. The aerosol filter element adopts the aerosol filter element of Example 1, and the filter element is arranged in the housing 8; the housing 8 is provided with an air inlet 81 and an air outlet 82, and the gas enters from the air inlet 81, is filtered by the filter element, and then is discharged to the outside of the aerosol filter through the air outlet 82. The height and angle parameter settings of the air inlet 81, the core seat 83, and the air outlet 82 of the filter can further reduce the overall filtration resistance of the aerosol filter and relieve the rear-end exhaust delivery pressure.

[0075] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. An aerosol filter element, characterized in that: The filter element comprises a filter element body and a sealing gasket (2), wherein the filter element body is mounted on the top surface of a core seat (83) of an aerosol filter, the filter element body is a vertically arranged cylindrical structure, the top end is closed, the bottom end surface serves as a docking surface with the core seat (83), an opening is provided on the bottom end surface to serve as an exhaust gas inlet (1) for docking with an air inlet hole (4) provided on the core seat (83), The sealing gasket (2) is arranged between the bottom surface of the filter element body and the core seat (83), and is pressed against the core seat (83) by the filter element body. The sealing gasket (2) is annular and arranged around the exhaust gas inlet (1). The radioactive tail gas enters the interior of the cylindrical structure from the tail gas inlet (1) at the bottom, passes through the central cavity in the cylindrical structure, is filtered by the side wall as the filtering area, and then flows out of the aerosol filter element with the outer surface of the cylindrical structure as the tail gas outlet.

2. The aerosol filter element according to claim 1, characterized in that: The filter element body comprises an end cover (5) and a filter material (6). The filter material (6) is in the form of a cylindrical structure with openings at both ends. The end caps (5) are connected to both ends of the filter material (6), and the end cap (5) at the top end closes the opening of the filter material (6). The end cap (5) at the bottom end serves as a docking surface, a sealing gasket (2) is arranged on the surface, and an exhaust gas inlet (1) is provided to allow radioactive exhaust gas to enter the filter material (6) through the exhaust gas inlet (1) for filtration.

3. The aerosol filter element according to claim 2, characterized in that: The filter material (6) is made of filter paper with a filtration area of ​​15 m2 to 30 m2, folded into a cylindrical structure with two ends open, and the number of folds is 500 to 1000.

4. The aerosol filter element according to claim 2, characterized in that: The filter element body further comprises a protective net (7), wherein the protective net (7) covers the outer surface and the inner surface of the filter material (6). The opening structure on the protection net (7) is circular or diamond-shaped, and the opening rate of the protection net (7) is 7% to 15.74%.

5. The aerosol filter element according to claim 1, characterized in that: When the air volume of radioactive tail gas inlet is within the range of 200m3 / h to 1000m3 / h, the filtration resistance of the aerosol filter element is not higher than 250Pa.

6. The aerosol filter element according to claim 1, characterized in that: The cross-sectional area of ​​the filter element body is 0.071 m2 to 0.229 m2, and the cross-sectional area of ​​the tail gas inlet (1) accounts for 16% to 37.35% of the cross-sectional area of ​​the filter element body.

7. The aerosol filter element according to claim 1, characterized in that: It also includes a detection member (3), The sealing gasket (2) is provided with an escape area at the annular center line, so that when the bottom surface of the filter element body and the top surface of the core seat (83) are fitted and connected, the sealing gasket (2) is sealed to form an annular sealing cavity (21) surrounding the joint between the exhaust gas inlet (1) and the air inlet hole (4). The detection element (3) is connected to the annular sealing cavity (21) and is used to obtain the sealing condition of the annular sealing cavity (21), and to determine whether the aerosol filter element is installed in place according to the sealing condition.

8. The aerosol filter element according to claim 7, characterized in that: The sealing gasket (2) comprises two annular sealing channels (22). One sealing path (22) surrounds the periphery of another sealing path (22), so that the area between the two sealing paths (22) forms the avoidance area. When the bottom surface of the filter element body and the top surface of the core seat (83) are fitted and connected, the bottom surface of the filter element body, the top surface of the core seat (83) and the two sealing channels (22) close the escape area in the middle, so that the escape area forms an annular sealing cavity (21) surrounding the joint between the exhaust gas inlet (1) and the air inlet hole (4).

9. The aerosol filter element according to claim 7, characterized in that: The detection element (3) comprises a connecting pipeline (31), a compressed gas supply device and a pressure measuring unit. The connecting pipeline (31) is connected between the annular sealed chamber (21) and the compressed gas supply device, and is used to input the compressed gas supplied by the compressed gas supply device into the annular sealed chamber (21), so that the gas pressure in the annular sealed chamber (21) reaches the set pressure. The detection end of the pressure measuring unit is connected to the connecting pipeline (31) and is used to obtain the pressure condition in the annular sealing chamber (21) through the connecting pipeline (31), and to determine that the aerosol filter element is installed in place when the pressure drop in the annular sealing chamber (21) is less than a set value within a set time.

10. An aerosol filter, characterized in that: comprising a housing (8) and an aerosol filter element according to any one of claims 1 to 9, An air inlet (81) and an air outlet (82) are provided on the wall surface of the shell (8), and a core seat (83) is provided in the inner cavity at a position between the air inlet (81) and the air outlet (82). The air inlet (4) is provided on the core seat (83). The aerosol filter element is accommodated in the inner cavity of the housing (8) and is mounted on the top surface of the core seat (83) so that the exhaust gas inlet (1) is connected to the air inlet hole (4).

11. The aerosol filter according to claim 10, characterized in that: The air inlet (81), the core seat (83) and the air outlet (82) are arranged in sequence from bottom to top. The inner cavity of the shell (8) is in the shape of a vertically arranged cylinder. The air inlet (81) is in the shape of a horizontal cylinder and is arranged along the tangent direction of the shell (8) so that the radioactive tail gas enters the aerosol filter element through the air inlet hole (4) along the inner wall of the shell (8) in a spiral streamline.

12. The aerosol filter according to claim 11, characterized in that: A guide tube (831) is provided on the bottom side of the core seat (83), the top opening of the guide tube (831) is connected to the air inlet hole (4), and the bottom opening is lower than the air inlet port (81). The radioactive tail gas follows the inner cavity wall of the shell (8) in a spiral streamline to reach the bottom opening of the guide tube (831) and then enters the aerosol filter element through the air inlet (4).

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