A device for sterilization using electron beam irradiation

Abstract

This invention discloses a device for sterilization using electron beam irradiation, belonging to the field of disinfection and sterilization technology. It includes a sterilization chamber equipped with electron beam sterilization equipment, and a processing box on top of the chamber. Three exhaust pipes are evenly arranged on the top wall of the processing box; a first exhaust fan is installed in the middle exhaust pipe, and second exhaust fans are installed in the other two exhaust pipes. Three air inlet pipes communicating with the sterilization chamber are located at the bottom of the processing box, with each exhaust pipe corresponding to one of the three air inlet pipes. A liftable catalyst bed is installed inside the processing box, and movable plates are respectively installed on the side walls of the processing box. This invention decomposes ozone, avoiding ozone corrosion of equipment and reducing maintenance costs. It also generates a strong airflow to prevent ozone leakage, protecting personnel health. Airflow optimization improves catalytic efficiency, and the structure automatically resets to adapt to batch operations, balancing safety, energy saving, and sterilization efficiency.

Description

Technical Field

[0001] This invention relates to the field of disinfection and sterilization technology, and specifically to a device for sterilization using electron beam irradiation. Background Technology

[0002] Electron beam sterilization is a highly efficient and environmentally friendly advanced technology. Its principle is to use a high-energy electron beam generated by an electron accelerator to instantly penetrate the irradiated item, destroying the DNA or RNA molecular structure of microorganisms (such as bacteria and viruses), thus rendering them inactive and achieving thorough sterilization. Compared with traditional methods such as high-temperature steam and ethylene oxide chemical sterilization, electron beam sterilization has significant advantages such as fast processing speed, no residue, no pollution, and the ability to be performed at room temperature. Therefore, it is widely used in the sterilization of heat-sensitive and chemically sensitive materials such as medical devices, pharmaceutical packaging, food, and scientific research supplies.

[0003] However, this technology faces a long-standing technical bottleneck: when the high-energy electron beam irradiates an object, it simultaneously interacts with the air inside the sterilization chamber, causing it to ionize. Oxygen molecules in the air absorb energy, decompose, and recombine to generate ozone.

[0004] Ozone production has a strong corrosive effect on the metal components, sensors, electrical components, and sealing materials inside sterilization equipment. Long-term accumulation can significantly reduce the lifespan and reliability of critical components, increase maintenance costs and downtime risks. Furthermore, ozone is a toxic and harmful gas with a strong irritant effect on the human respiratory tract. Improper handling can lead to ozone leaks from the equipment that endanger the health of operators and pollute the working environment. Summary of the Invention

[0005] The purpose of this invention is to provide a device for sterilization using electron beam irradiation, which solves the following technical problem: when electron beam irradiation is used for sterilization, it ionizes and generates ozone, which not only corrodes the equipment and affects its service life, but also poses a threat to human health.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] An apparatus for sterilization using electron beam irradiation includes a sterilization chamber, on which an electron beam sterilization device is installed, and a processing box is provided on the top of the sterilization chamber.

[0008] The top wall of the processing box is evenly provided with three exhaust pipes. The first exhaust fan is installed in the middle exhaust pipe, and the second exhaust fan is installed in the other two exhaust pipes. The bottom of the processing box is provided with three air inlet pipes that are connected to the sterilization chamber, and the three exhaust pipes correspond one-to-one with the three air inlet pipes.

[0009] The processing box is equipped with a liftable catalyst bed. Movable moving plates are respectively installed on the two side walls of the processing box. Two guide plates are rotatably installed on the bottom wall of the processing box, and the two guide plates correspond one-to-one with two second exhaust fans.

[0010] The inner surface of the top wall of the processing box is symmetrically equipped with fixing blocks. Two contact switches are installed on the side walls of the two fixing blocks that are close to each other. The two contact switches are electrically connected to the two second exhaust fans respectively.

[0011] As a further aspect of the present invention: the sterilization chamber is divided into a transmission zone and an irradiation zone by a partition structure. The transmission zone and the irradiation zone are equipped with a conveyor device for transporting goods. The conveyor device is a U-shaped conveyor belt structure. The conveyor belt structure includes, in sequence according to the direction of goods flow, an input isolation section, an input irradiation section, a flipping section, an output irradiation section, and an output isolation section. The input isolation section and the output isolation section are located in the transmission zone, while the input irradiation section, the flipping section, and the output irradiation section are located in the irradiation zone. The flipping section is equipped with a flipping mechanism, and the input irradiation section and the output irradiation section are located below the electron beam sterilization equipment.

[0012] As a further aspect of the present invention: the partition structure is a lead plate partition door that can slide left and right, including a first input partition door and a second input partition door disposed at both ends of the input isolation section, and a first output partition door and a second output partition door disposed at both ends of the output isolation section; the first input partition door, the second input partition door, the first output partition door and the second output partition door are all electrically controllable side-moving movable sealed lead doors.

[0013] As a further aspect of the present invention: the cross-section of the movable plate is an L-shaped structure, and a bidirectional screw is rotatably installed between the two movable plates and the inner walls of the two sides of the processing box, and the bidirectional screw is threadedly connected to the two movable plates respectively. A drive motor is installed on one side wall of the processing box, and the output shaft of the drive motor is connected to one end of the bidirectional screw.

[0014] As a further embodiment of the present invention: a first bevel gear is installed on the bidirectional screw, a fixed rod is installed on the inner wall of the processing box, a lead screw is rotatably installed on the fixed rod, a second bevel gear is installed at the top of the lead screw, the second bevel gear meshes with the first bevel gear, and the lead screw is threadedly connected to the catalyst bed.

[0015] As a further aspect of the present invention: a vertical rod is connected to the bottom of the catalyst bed, and push rods are symmetrically fixed on the vertical rods. Push balls are installed at the ends of the two push rods that are far apart from each other, and the two push balls are in contact with the two guide plates respectively.

[0016] As a further embodiment of the present invention: a closing plate is fixed to the bottom of the vertical rod, the closing plate includes a fixed baffle fixed to the vertical rod, movable baffles are rotatably installed on both sides of the fixed baffle, and limit blocks are symmetrically arranged on the fixed baffle.

[0017] As a further aspect of the present invention, an electric heating tube is installed inside the catalyst bed.

[0018] The beneficial effects of this invention are:

[0019] (1) This invention preheats the catalyst bed so that ozone is rapidly catalytically decomposed into oxygen after being drawn into the treatment chamber, thus eliminating the corrosion of metal components, sensors, electrical components and sealing materials in the sterilization chamber by ozone from the source; and the exothermic decomposition reaction can maintain the temperature of the catalyst bed, reducing additional heating energy consumption and meeting the energy-saving requirements; this avoids the aging of equipment components caused by long-term ozone accumulation, extends the service life of key components, and reduces maintenance costs and downtime risks caused by equipment failure;

[0020] (2) When the goods are delivered, the three exhaust fans start simultaneously to maximize the exhaust volume and form a strong airflow pointing into the irradiation area. This completely blocks the path of ozone diffusion outward with the opening of the partition door, effectively avoids the irritation and harm of ozone to the respiratory tract of operators, prevents pollution of the working environment, solves the safety hazard of ozone leakage in traditional devices, and meets the safety standards for the control of toxic and harmful gases.

[0021] (3) When the goods are delivered, the catalyst bed is raised, the guide plate is deflected to near vertical and the sealing plate is opened, so that the three airflows are fully mixed and decelerated in the processing box to form a uniform airflow field, and then pass smoothly through the catalyst bed. This avoids uneven catalyst utilization caused by local concentration of airflow, realizes the full and efficient function of the catalyst bed, maximizes ozone treatment efficiency, and prevents airflow impact from affecting catalyst stability.

[0022] (4) After the batch of goods is delivered, the drive motor rotates in the opposite direction to automatically reset the moving plate, catalyst bed, guide plate, etc. The next batch of sterilization can be started without manual adjustment, eliminating the tedious steps of manual reset in traditional devices, adapting to the sterilization needs of continuous batch goods, reducing process interval time, improving the overall sterilization operation efficiency, and meeting the needs of industrial batch processing scenarios. Attached Figure Description

[0023] The invention will now be further described with reference to the accompanying drawings.

[0024] Figure 1 This is a side view of the sterilization chamber of the present invention;

[0025] Figure 2 This is a top view of the sterilization chamber of the present invention;

[0026] Figure 3 This is a three-dimensional structural schematic diagram of the processing box of the present invention;

[0027] Figure 4 This is a first-view structural diagram of the interior of the processing box of the present invention;

[0028] Figure 5 This is a second-view structural diagram of the interior of the processing box of the present invention;

[0029] Figure 6 This is a schematic diagram of the structure of the vertical rod and the closing plate of the present invention.

[0030] In the diagram: 1. Sterilization chamber; 2. Electron beam sterilization equipment; 3. Processing box; 4. Input isolation section; 5. Input irradiation section; 6. Tilting section; 7. Output irradiation section; 8. Output isolation section; 9. First input isolation door; 10. Second input isolation door; 11. First output isolation door; 12. Second output isolation door; 13. Exhaust pipe; 14. First exhaust fan; 15. Second exhaust fan; 16. Inlet pipe; 17. Moving plate; 18. Bidirectional screw; 19. Drive motor; 20. Catalyst bed; 21. Guide plate; 22. First bevel gear; 23. Fixed rod; 24. Lead screw; 25. Second bevel gear; 26. Vertical rod; 27. Push rod; 28. Push ball; 29. ​​Sealing plate; 2901. Fixed baffle; 2902. Movable baffle; 2903. Limit block; 30. Fixed block; 31. Touch switch.

[0031] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the invention. To better illustrate this embodiment, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual size and shape of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Please see Figures 1 to 5As shown, this invention is a device for sterilization using electron beam irradiation, comprising a sterilization chamber 1, an electron beam sterilization device 2 installed on the sterilization chamber 1, and a processing box 3 installed on the top of the sterilization chamber 1; three exhaust pipes 13 are evenly arranged on the top wall of the processing box 3, a first exhaust fan 14 is installed in the middle exhaust pipe 13, and second exhaust fans 15 are installed in the other two exhaust pipes 13; three air inlet pipes 16 connected to the sterilization chamber 1 are arranged at the bottom of the processing box 3, and the three exhaust pipes 13 correspond one-to-one with the three air inlet pipes 16; a liftable catalyst bed 20 is arranged inside the processing box 3, and two side walls of the processing box 3 are respectively provided with The processing chamber 3 has a movable plate 17. Two guide plates 21 are rotatably mounted on the bottom wall of the processing chamber 3, and the two guide plates 21 correspond one-to-one with two second exhaust fans 15. Fixed blocks 30 are symmetrically installed on the inner surface of the top wall of the processing chamber 3. Two contact switches 31 are installed on the side walls of the two fixed blocks 30 that are close to each other. The two contact switches 31 are electrically connected to the two second exhaust fans 15 respectively. An electric heating tube is installed in the catalyst bed 20. The catalyst is preheated by the electric heating tube to achieve the best catalytic activity. After the goods are sent into the sterilization chamber 1, the goods are sterilized by the electron beam sterilization equipment 2. During sterilization, the sterilization chamber 1 is relatively closed. In the first state, the first exhaust fan 14 is always working, extracting ozone, which is then decomposed by the catalyst bed 20 and finally discharged through the exhaust pipe 13. After the goods are disinfected, the sterilization chamber 1 needs to be opened. Beforehand, the two moving plates 17 should be moved apart to expose the other two exhaust pipes 13. When the moving plates 17 move and contact the touch switch 31, the two second exhaust fans 15 start, instantly maximizing the exhaust volume. This ensures that a strong airflow directed towards the interior of the irradiation chamber is formed the moment the sterilization chamber 1 is opened, effectively preventing the ozone-containing air from diffusing outwards and absolutely guaranteeing the health and safety of the operators; because ozone... The generation rate is relatively stable and predictable. A single exhaust fan operating at its rated airflow is sufficient to handle the ozone continuously generated by the electron beam and maintain a basic negative pressure in the irradiation chamber. Operating only one exhaust fan can significantly save on electricity costs and reduce long-term operating costs. The staged fan control strategy cleverly balances operational efficiency and absolute safety. It is worth noting that the catalyst in the catalyst bed 20 is a honeycomb ceramic catalyst with active ingredients. The electric heating tube heats the catalyst to about 80°C to achieve optimal catalytic activity. A torsion spring is installed between the guide plate 21 and the treatment box 3 to ensure the angle of the guide plate 21 and its subsequent reset.

[0034] See Figure 1 and Figure 2The sterilization chamber 1 is divided into a transmission zone and an irradiation zone by a partition structure. Conveying devices for transporting goods are installed in both zones. These conveying devices are U-shaped conveyor belt structures, which, in the direction of goods flow, sequentially include an input isolation section 4, an input irradiation section 5, a turning section 6, an output irradiation section 7, and an output isolation section 8. The input isolation section 4 and output isolation section 8 are located in the transmission zone, while the input irradiation section 5, turning section 6, and output irradiation section 7 are located in the irradiation zone. The turning section 6 is equipped with a turning mechanism. The input irradiation section 5 and output irradiation section 7 are located below the electron beam sterilization equipment 2. The partition structure consists of lead plate partition doors that can slide left and right, including a first input partition door 9 and a second input partition door 10 located at both ends of the input isolation section 4, and a first output partition door 11 and a second output partition door 12 located at both ends of the output isolation section 8. 0. Both the first output partition door 11 and the second output partition door 12 are electrically controllable, side-moving, sealed lead doors. In actual operation, after the first input partition door 9 at the inlet is opened, the goods are transported to the transmission area. The first input partition door 9 is closed, and the second input partition door 10 is opened. The goods are then transported to the input irradiation section 5 via a conveyor belt, where the surface of the goods is disinfected by the radiation emitted by the electron beam. After disinfection, the undisinfected bottom surface of the goods is flipped over by a flipping mechanism and then transported to the output irradiation section 7 via a conveyor belt for further disinfection. After disinfection is completed, the second output partition door 12 is opened, and the first output partition door 11 is closed. The goods are then transported from the output irradiation section 7 to the output isolation section 8 via a conveyor belt. After the goods leave the output irradiation section 7, the second output partition door 12 is closed, and the first output partition door 11 is opened. The disinfection process is completed, and the goods are then transported to their storage or handling destination by a conveyor belt.

[0035] See Figure 4 and Figure 5 The movable plate 17 has an L-shaped cross-section. Two movable plates 17 are connected to a bidirectional screw 18 rotatably between the inner walls of both sides of the processing chamber 3. The bidirectional screw 18 is threadedly connected to each of the two movable plates 17. A drive motor 19 is installed on one side wall of the processing chamber 3, and the output shaft of the drive motor 19 is connected to one end of the bidirectional screw 18. During sterilization, only the first exhaust fan 14 operates. The two movable plates 17 block the other two exhaust pipes 13, and the two second exhaust fans 15 are in standby mode, reducing their mechanical wear. When goods need to be transported to the transfer area, in order to prevent ozone from leaking to the outside, the drive motor 19 is started in advance. The bidirectional screw 18 drives the two moving plates 17 to move away from each other. After the moving plates 17 move and contact the touch switch 31, the two second exhaust fans 15 start. At this time, the three exhaust fans start at the same time, maximizing the exhaust volume instantly. This ensures that a strong airflow is formed at the moment of opening, pointing towards the interior of the irradiation room, effectively preventing the ozone-containing air in the room from spreading outward, and absolutely protecting the health and safety of the operators.

[0036] See Figure 4 , Figure 5 and Figure 6 A first bevel gear 22 is mounted on the bidirectional screw 18. A fixed rod 23 is mounted on the inner wall of the processing box 3. A lead screw 24 is rotatably mounted on the fixed rod 23. A second bevel gear 25 is mounted on the top of the lead screw 24. The second bevel gear 25 meshes with the first bevel gear 22. The lead screw 24 is threadedly connected to the catalyst bed 20. A vertical rod 26 is connected to the bottom of the catalyst bed 20. Push rods 27 are symmetrically fixed on the vertical rod 26. Push balls 2 are mounted on the ends of the two push rods 27 that are far apart from each other. 8. The two push balls 28 are in contact with the two guide plates 21 respectively; a sealing plate 29 is fixed at the bottom of the vertical rod 26. The sealing plate 29 includes a fixed baffle 2901 fixed to the vertical rod 26. Movable baffles 2902 are rotatably installed on both sides of the fixed baffle 2901, and limit blocks 2903 are symmetrically arranged on the fixed baffle 2901; During normal sterilization, the two guide plates 21 are in an inclined state, and the sealing plate 29 blocks one air inlet pipe 16, so that the ozone in the sterilization chamber 1 is... Air can only enter the processing chamber 3 through the air inlet pipes 16 on both sides, and after being guided by the guide plate 21, it enters the catalyst bed 20 evenly for processing. When the drive motor 19 starts, the bidirectional screw 18 and the first bevel gear 22 rotate, driving the second bevel gear 25 and the lead screw 24 to rotate, thereby raising the catalyst bed 20 and driving the vertical rod 26 to rise. This causes the two push balls 28 to push the guide plate 21 to deflect, making the guide plate 21 close to a vertical state, and the sealing plate 29 also moves away from the air inlet pipe 16. Under the action of gravity, the two movable baffles 2902 deflect, allowing the middle air inlet pipe 16 to smoothly enter. At this time, the airflow can enter the processing chamber 3 simultaneously through the three air inlet pipes 16, and the distance between the catalyst bed 20 and the air inlet pipe 16 also increases. The three airflows have space in the chamber to fully mix and decelerate first, forming a uniform airflow field before smoothly passing through the catalyst bed 20. The catalyst bed 20 is used evenly, maximizing the processing efficiency.

[0037] The working principle of this invention is as follows: The catalyst in the catalyst bed 20 is preheated, the first exhaust fan 14 is in operation to ensure a certain negative pressure in the sterilization chamber 1, the two guide plates 21 are tilted, and the sealing plate 29 blocks the middle air inlet pipe 16 (e.g., Figure 4 As shown, a batch of goods is sent into the sterilization chamber 1. The goods are moved in different areas by the conveyor belt. After the goods enter the irradiation area, the electron beam sterilization equipment 2 sterilizes the goods. The generated ozone is drawn into the processing box 3 through the air inlet pipes 16 on both sides. After being guided by the guide plate 21, it passes evenly through the catalyst bed 20. The ozone molecules are catalytically decomposed into oxygen at the moment they come into contact with the catalyst surface. The decomposition reaction itself is an exothermic reaction. The heat released by this part of the reaction can help maintain the temperature of the catalyst bed 20, effectively saving energy.

[0038] When goods need to be delivered, the drive motor 19 is started in advance, and the two moving plates 17 are moved away from each other by the bidirectional screw 18. After the moving plates 17 move and contact the touch switch 31, the two second exhaust fans 15 are started. At this time, all three exhaust fans start at the same time, maximizing the exhaust volume instantly. This ensures that a strong airflow is formed at the moment the partition door is opened, pointing into the irradiation area, effectively preventing the ozone-containing air in the room from spreading outward, and absolutely protecting the health and safety of the operators.

[0039] While the bidirectional screw 18 rotates, the first bevel gear 22 rotates, driving the second bevel gear 25 and the lead screw 24 to rotate, thereby raising the catalyst bed 20 and driving the vertical rod 26 to rise. This causes the two push balls 28 to push the guide plate 21 to deflect, making the guide plate 21 nearly vertical, and the sealing plate 29 also moves away from the air inlet pipe 16. At this time, the airflow can enter the processing box 3 simultaneously through the three air inlet pipes 16. The guide plate 21 will not obstruct the rapid passage of the airflow. At this time, the distance between the catalyst bed 20 and the air inlet pipe 16 also increases. The three airflows have space in the box to mix and decelerate fully first, forming a uniform airflow field before passing smoothly through the catalyst bed 20. The catalyst bed 20 is used evenly, maximizing the processing efficiency.

[0040] Once all the goods in the batch have been delivered, the output shaft of the drive motor 19 rotates in the opposite direction, causing the moving plate 17, catalyst bed 20, guide plate 21, and sealing plate 29 to automatically reset, so that the next batch of goods can be disinfected.

[0041] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. An apparatus for sterilization by electron beam irradiation comprising a sterilization chamber (1) on which an electron beam sterilization device (2) is mounted, characterized in that, The top of the sterilization bin (1) is also provided with a treatment box (3); The top wall of the treatment box (3) is uniformly provided with three exhaust pipes (13), the middle exhaust pipe (13) is provided with a first air extractor (14), the other two exhaust pipes (13) are provided with a second air extractor (15), and the bottom of the treatment box (3) is provided with three air inlet pipes (16) communicated with the sterilization bin (1), and the three exhaust pipes (13) and the three air inlet pipes (16) correspond one by one. A liftable catalyst bed (20) is arranged in the treatment box (3), movable moving plates (17) are arranged on the two side walls of the treatment box (3), and two guide plates (21) are rotatably installed on the bottom wall of the treatment box (3), and the two guide plates (21) correspond to the two second air extractors (15) one by one. The inner surface of the top wall of the treatment box (3) is symmetrically provided with fixed blocks (30), point touch switches (31) are arranged on the side walls close to the two fixed blocks (30), and the two point touch switches (31) are electrically connected with the two second air extractors (15) respectively. The cross section of the moving plate (17) is L-shaped structure, two moving plates (17) are rotatably installed between the two inner walls of the treatment box (3), the bidirectional screw rod (18) is threadedly connected with the two moving plates (17) respectively, a drive motor (19) is installed on one side wall of the treatment box (3), and the output shaft of the drive motor (19) is connected with one end of the bidirectional screw rod (18). The bidirectional screw rod (18) is provided with a first bevel gear (22), a fixed rod (23) is arranged on the inner wall of the treatment box (3), a lead screw (24) is rotatably installed on the fixed rod (23), a second bevel gear (25) is installed on the top end of the lead screw (24), the second bevel gear (25) is engaged with the first bevel gear (22), and the lead screw (24) is threadedly connected with the catalyst bed (20).

2. The apparatus for sterilization by electron beam irradiation according to claim 1, wherein The sterilization bin (1) is divided into a transmission area and an irradiation area by a partition structure, a conveying device for conveying goods is arranged in the transmission area and the irradiation area, the conveying device is a U-shaped conveying belt structure, the conveying belt structure sequentially includes an input isolation section (4), an input irradiation section (5), a turnover section (6), an output irradiation section (7) and an output isolation section (8) according to the flow direction of the goods, the input isolation section (4) and the output isolation section (8) are located in the transmission area, the input irradiation section (5), the turnover section (6) and the output irradiation section (7) are located in the irradiation area, the turnover section (6) is provided with a turnover mechanism, and the input irradiation section (5) and the output irradiation section (7) are located below the electron beam sterilization equipment (2).

3. A device for sterilization by electron beam irradiation according to claim 2, characterized in that, The partition structure is a left-right translatable lead plate partition door, comprising a first input partition door (9) and a second input partition door (10) arranged at two ends of an input isolation section (4) and a first output partition door (11) and a second output partition door (12) arranged at two ends of an output isolation section (8); the first input partition door (9), the second input partition door (10), the first output partition door (11) and the second output partition door (12) are all electrically controllable side-moving movable sealing lead doors.

4. The apparatus for sterilization by electron beam irradiation according to claim 1, wherein The bottom of the catalyst bed (20) is connected with a vertical rod (26), the vertical rod (26) is symmetrically fixed with push rods (27), the two ends of the two push rods (27) away from each other are both installed with push balls (28), and the two push balls (28) are in contact with two guide plates (21) respectively.

5. A device for sterilization by electron beam irradiation according to claim 4, characterized in that, The bottom of the vertical rod (26) is fixed with a closing plate (29), the closing plate (29) comprises a fixed baffle (2901) fixed with the vertical rod (26), both sides of the fixed baffle (2901) are rotatably installed with movable baffles (2902), and the fixed baffle (2901) is symmetrically provided with limit blocks (2903).

6. The apparatus for sterilization by electron beam irradiation according to claim 1, wherein The catalyst bed (20) is installed with an electric heating pipe.

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