A liquid ammonia evaporator for electronic-grade ammonia production

Abstract

This invention relates to a liquid ammonia evaporator for producing electronic-grade ammonia water. The liquid ammonia evaporator includes a shell, within which a partition divides the interior into an evaporation chamber and a purification chamber. The upper end of the partition has a protruding portion, and the outer wall of the protruding portion has an air outlet. A rotating shaft is rotatably mounted within the purification chamber. The shell has a drive mechanism for driving the rotating shaft. Several purifiers are arranged around the rotating shaft within the purification chamber. Each purifier includes an outer shell, within which a partition divides the interior into a heating chamber and an exhaust chamber. A heating coil is located within the heating chamber. The lower end of the outer shell has an air inlet communicating with the heating chamber, and the air inlet is equipped with an air inlet check valve. The partition has a connecting hole connecting the heating chamber and the exhaust chamber, and the connecting hole is equipped with a connecting check valve. This invention's liquid ammonia evaporator for producing electronic-grade ammonia water improves the purity of ammonia vapor, helps to improve the purity of ammonia gas, and enables the produced ammonia water to reach electronic-grade standards.

Description

Technical Field

[0001] This invention belongs to the field of electronic-grade ammonia production technology, specifically relating to a liquid ammonia evaporator for electronic-grade ammonia production. Background Technology

[0002] In the semiconductor industry, even the slightest addition of impurity elements to pure semiconductor products can cause drastic changes in their resistivity. Therefore, the semiconductor industry maintains extremely high purity requirements for the chemical materials used, typically employing electronic-grade chemicals.

[0003] Electronic-grade ammonia is one of the eight commonly used electronic-grade chemical materials in the semiconductor industry, ranking third in consumption among electronic product manufacturers. It is primarily used in processes such as diffusion, etching, and cleaning of silicon wafers. Utilizing the weak alkalinity of ammonia, it activates the surface of silicon wafers and microparticles, removing surface particles and some metallic impurities. Therefore, electronic-grade ammonia is widely used in chip cleaning.

[0004] The main production processes for electronic-grade ammonia water include batch distillation, membrane filtration absorption, and resin filtration. While these processes vary, most involve evaporation, purification, and absorption. A compressor pressurizes liquid ammonia from a raw material tank into an evaporator, where hot steam evaporates it into ammonia gas. The vaporized ammonia gas then passes through a water separator and an activated carbon adsorber to obtain purified ammonia. After purification and filtration, the ammonia gas is treated with adsorption resin for oil removal, followed by washing with ultrapure water and saturated ammonia water to remove impurities. The treated ammonia gas is then separated into water vapor and ammonia gas using a water vapor separator. The separated ammonia gas is then absorbed by ultrapure water in an absorption tower and ultrafiltered to obtain electronic-grade ammonia water.

[0005] The key element in the production of electronic-grade ammonia water lies in the preparation of high-purity ammonia gas. In the existing technology, the ammonia gas prepared by liquid ammonia evaporators often contains a large number of droplets. The impurities present in the droplets will reduce the purity of the ammonia gas, resulting in the ammonia water produced not meeting the electronic grade. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a liquid ammonia evaporator for electronic-grade ammonia production.

[0007] The technical solution of the liquid ammonia evaporator for electronic-grade ammonia production according to the present invention is as follows:

[0008] A liquid ammonia evaporator for producing electronic-grade ammonia water includes a shell. Inside the shell, a partition divides the interior into an evaporation chamber and a purification chamber. The upper end of the partition has a protrusion, and the outer wall of the protrusion has an outlet. A rotating shaft is rotatably mounted inside the purification chamber. The shell has a drive mechanism for rotating the shaft. Several purifiers are arranged around the rotating shaft inside the purification chamber. Each purifier includes an outer shell, inside which a partition divides the interior into a heating chamber and an exhaust chamber. The device includes a heating coil. The lower end of the housing has an air inlet communicating with the heating chamber, and the air inlet is equipped with an air inlet check valve. The partition has a connecting hole communicating with the heating chamber and the exhaust chamber, and the connecting hole is equipped with a connecting check valve. The upper end of the housing has an exhaust hole communicating with the exhaust chamber, and the exhaust hole is equipped with an exhaust check valve. A sliding plate is installed inside the exhaust chamber as a guide. A first magnet is located on one side of the sliding plate. A second magnet and a third magnet are located on both sides of the rotating shaft, with the outer magnetic poles of the second and third magnets opposite.

[0009] Furthermore, a sealing plug for sealing the air outlet is slidably sealed inside the protrusion. The upper end of the sealing plug is provided with a connecting rod, and the upper end of the connecting rod is provided with a lower turntable. A return spring is provided between the lower turntable and the protrusion. The lower end of the rotating shaft is provided with an upper turntable, and the lower side of the upper turntable and the upper side of the lower turntable are respectively provided with protrusions.

[0010] Furthermore, the upper end of the protrusion is sealed, and the upper end of the protrusion is provided with a through hole. The lower end of the outer shell is sealed to the rotating shaft through a sealing plate and a sealing bearing.

[0011] Furthermore, the heating chamber is provided with several guide plates that match the heating coil and allow the gas entering the heating chamber to flow along the extension direction of the heating coil. The upper end of the shell is provided with an outlet pipe that communicates with the purification chamber.

[0012] Furthermore, the driving mechanism includes a drive motor, and a motor mounting base is provided at the upper end of the housing. The drive motor is fixedly connected to the upper side of the motor mounting base, and the output shaft of the drive motor extends into the motor mounting base. The output shaft of the drive motor is connected to the rotating shaft through a coupling.

[0013] Furthermore, the partition includes a conical plate that is smaller at the top and larger at the bottom, the protrusion is disposed at the upper end of the conical plate, and the outer wall of the housing is provided with a liquid outlet pipe that communicates with the upper end of the lower side of the conical plate, and the liquid outlet pipe is provided with a shut-off valve.

[0014] Furthermore, a defogging screen is provided inside the heating chamber, and fixed plates are provided on the upper and lower sides of the defogging screen on the cavity wall of the heating chamber. A guide rod is provided between the two fixed plates, and the frame of the defogging screen is guided and installed on the guide rod. Two buffer springs are respectively installed on the guide rod on the upper and lower sides of the defogging screen. The two ends of the buffer springs are respectively connected to the mounting plate and the frame of the defogging screen. A transmission rod is fixedly connected to the lower end of the sealing plug, and a fixed block is provided at the lower end of the transmission rod to push the defogging screen downward when the sealing plug moves downward.

[0015] This invention provides a liquid ammonia evaporator for the production of electronic-grade ammonia water, which has the following advantages:

[0016] In the electronic-grade ammonia water production liquid ammonia evaporator of this invention, liquid ammonia evaporates in the evaporation chamber. The evaporated ammonia vapor is then demisted by a demister and enters the purification chamber. A drive motor drives a rotating shaft to rotate, and the second and third magnets on the shaft rotate with it, causing a sliding plate to slide left and right. As the sliding plate slides to the right, it draws gas from the heating chamber into the exhaust chamber, where it is heated by the heating coil, causing the liquid in the gas to evaporate. As the sliding plate slides to the left, it discharges gas from the exhaust chamber, thus purifying the ammonia vapor. The rotation of the shaft drives the upper rotating plate, while the lower rotating plate moves up and down under the action of the upper rotating plate and the return spring. During this up-and-down movement, the sealing plug periodically seals and unseals the vent, causing the ammonia vapor in the evaporation chamber to intermittently enter the purification chamber, reducing the vapor density and improving the purification effect. The up-and-down movement of the sealing plug also causes the fixed block to move up and down, vibrating the demister and shaking off any droplets adhering to it. Compared to existing technologies, the liquid ammonia evaporator for producing electronic-grade ammonia water of the present invention improves the purity of ammonia vapor, which helps to improve the purity of ammonia gas and enables the produced ammonia water to reach electronic grade. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a liquid ammonia evaporator for producing electronic-grade ammonia water according to an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the purifier in the liquid ammonia evaporator for producing electronic-grade ammonia water according to an embodiment of the present invention;

[0019] Figure 3 yes Figure 1 Enlarged view of point A in the middle;

[0020] Figure 4 yes Figure 1 Enlarged view of point B in the middle;

[0021] Figure 5 This is a schematic diagram of the upper rotating disk in the liquid ammonia evaporator for producing electronic-grade ammonia water according to an embodiment of the present invention;

[0022] In the diagram: 1. Shell; 2. Evaporation chamber; 3. Purification chamber; 4. Gas outlet pipe; 5. Liquid outlet pipe; 6. Shut-off valve; 7. Conical plate; 8. Protrusion; 9. Gas outlet; 10. Perforation; 11. Sealing plug; 12. Transmission rod; 13. Fixing block; 14. Demisting screen; 15. Mounting plate; 16. Buffer spring; 17. Purifier; 18. Motor mounting base; 19. Drive motor; 20. Rotating shaft; 21. Second magnet 22. Iron; 23. Third magnet; 24. Upper turntable; 25. Protrusion; 26. Lower turntable; 27. Return spring; 28. Connecting rod; 29. ​​Sealing plate; 30. Sealed bearing; 31. Housing; 32. Heating chamber; 33. Exhaust chamber; 34. Partition; 35. Heating coil; 36. Guide plate; 37. Slide plate; 38. First magnet; 39. Intake check valve; 30. Connecting check valve; 30. Exhaust check valve. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0024] Specific embodiments of the liquid ammonia evaporator for electronic-grade ammonia water production of the present invention are as follows: Figures 1 to 5 As shown, the device includes a housing 1, which contains a partition that divides the interior of the housing 1 into an evaporation chamber 2 and a purification chamber 3. The upper end of the partition has a protrusion 8, and the outer wall of the protrusion 8 has an exhaust port 9. A rotating shaft 20 is rotatably mounted inside the purification chamber 3. The housing 1 has a drive mechanism for rotating the rotating shaft 20. Several purifiers 17 are arranged around the rotating shaft 20 inside the purification chamber 3. Each purifier 17 includes a housing 29, which contains a partition 32 that divides the interior of the housing 29 into a heating chamber 30 and an exhaust chamber 31. A heating coil 33 is located inside the heating chamber 30. The lower end of the outer casing 29 is provided with an air inlet that communicates with the heating chamber 30. An air inlet one-way valve 37 is provided on the air inlet. The partition 32 is provided with a connecting hole that connects the heating chamber 30 and the exhaust chamber 31. A connecting one-way valve 38 is provided on the connecting hole. The upper end of the outer casing 1 is provided with an exhaust hole that communicates with the exhaust chamber 31. An exhaust one-way valve 39 is provided on the exhaust hole. A slide plate 35 is installed inside the exhaust chamber 31. A first magnet 36 is provided on one side of the slide plate 35. A second magnet 21 and a third magnet 22 are provided on both sides of the rotating shaft 20. The magnetic poles of the second magnet 21 and the third magnet 22 are opposite.

[0025] A sealing plug 11 for sealing the vent 9 is slidably installed inside the protrusion 8. A connecting rod 26 is provided at the upper end of the sealing plug 11, and a lower turntable 24 is provided at the upper end of the connecting rod 26. A return spring 25 is provided between the lower turntable 24 and the protrusion 8. An upper turntable 23 is provided at the lower end of the rotating shaft 20. Protrusions 231 are respectively provided on the lower side of the upper turntable 23 and the upper side of the lower turntable 24. The upper end of the protrusion 8 is sealed, and a through hole 10 is provided at the upper end of the protrusion 8. The lower end of the outer shell 29 is sealed to the rotating shaft 20 through a sealing plate 27 and a sealing bearing 28.

[0026] The heating chamber 30 is equipped with several guide plates 34 that match the heating coil 33 and allow the gas entering the heating chamber 30 to flow along the extension direction of the heating coil 33. The upper end of the housing 1 is provided with an outlet pipe 4 that communicates with the purification chamber 3. The driving mechanism includes a drive motor 19. The upper end of the housing 1 is provided with a motor mounting base 18. The drive motor 19 is fixedly connected to the upper side of the motor mounting base 18. The output shaft of the drive motor 19 extends into the motor mounting base 18. The output shaft of the drive motor 19 is connected to the rotating shaft 20 through a coupling.

[0027] The partition includes a conical plate 7 that is smaller at the top and larger at the bottom, with a protrusion 8 located at the upper end of the conical plate 7. A liquid outlet pipe 5, communicating with the upper lower end of the conical plate 7, is located on the outer wall of the housing 1. A shut-off valve 6 is installed on the liquid outlet pipe 5. A demisting screen 14 is installed inside the heating chamber 30. Fixing plates are located on the upper and lower sides of the demisting screen 14 on the wall of the heating chamber 30. A guide rod is located between the two fixing plates. The frame of the demisting screen 14 is guided and mounted on the guide rod. Two buffer springs 17, located on the upper and lower sides of the demisting screen 14 respectively, are fitted on the guide rod. The two ends of the buffer springs 17 are connected to the mounting plate 16 and the frame of the demisting screen 14 respectively. A transmission rod 12 is fixedly connected to the lower end of the sealing plug 11. A fixing block 13 is located at the lower end of the transmission rod 12 to push the demisting screen 14 downwards when the sealing plug 11 moves downwards.

[0028] When the liquid ammonia evaporator for electronic-grade ammonia production of the present invention is used, the liquid ammonia evaporates in the evaporation chamber 2. The evaporated ammonia vapor is demisted by the demister 14 and then enters the purification chamber 3. The drive motor 19 drives the rotating shaft 20 to rotate. The second magnet 21 and the third magnet 22 on the rotating shaft 20 rotate with the rotating shaft 20, and the second magnet 21 and the third magnet 22 drive the sliding plate 35 to slide left and right. During the sliding of the sliding plate 35 to the right, the gas in the heating chamber 30 is drawn into the exhaust chamber 31. During this process, the gas is heated by the heating coil 33, and the liquid in the gas evaporates due to the heat. During the sliding of the sliding plate 35 to the left, the gas in the exhaust chamber 31 is discharged, thereby purifying the ammonia vapor. When the rotating shaft 20 rotates, it drives the upper rotating plate 23 to rotate. The lower rotating plate 24 moves up and down under the action of the upper rotating plate 23 and the return spring 25. During the up and down movement of the sealing plug 11, the vent hole 9 is periodically sealed and unsealed, so that the ammonia vapor in the evaporation chamber 2 intermittently enters the purification chamber 3, reducing the vapor density in the purification chamber 3 and helping to improve the purification effect of the purifier 17. During the up-and-down movement of the sealing plug 11, the fixed block 13 moves up and down, causing the demister 14 to vibrate up and down, shaking off the liquid droplets attached to the demister 14. Compared with the prior art, the liquid ammonia evaporator for producing electronic-grade ammonia water of the present invention improves the purity of ammonia vapor, which helps to improve the purity of ammonia gas and enables the produced ammonia water to reach electronic grade.

[0029] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A liquid ammonia evaporator for producing electronic-grade ammonia water, characterized in that, The device includes a housing, within which a partition divides the interior of the housing into an evaporation chamber and a purification chamber. The upper end of the partition has a protruding portion, and the outer wall of the protruding portion has an air outlet. A rotating shaft is rotatably mounted within the purification chamber. The housing has a drive mechanism for driving the rotating shaft. Several purifiers are arranged around the rotating shaft within the purification chamber. Each purifier includes a shell, within which a partition divides the interior of the shell into a heating chamber and an exhaust chamber. A heating coil is located within the heating chamber. An air inlet communicating with the heating chamber is located at the lower end of the shell, and an air inlet check valve is located on the air inlet. A connecting hole communicating with the heating chamber and the exhaust chamber is located on the partition, and a connecting check valve is located on the connecting hole. An exhaust hole communicating with the exhaust chamber is located at the upper end of the shell, and an exhaust check valve is located on the exhaust hole. A sliding plate is guided within the exhaust chamber. A first magnet is located on one side of the sliding plate. Second and third magnets are located on both sides of the rotating shaft. The magnetic poles on both sides are opposite. The second magnet and the third magnet rotate with the rotating shaft and drive the slide plate to slide left and right. The lower end of the outer shell is sealed to the rotating shaft through a sealing plate and a sealing bearing. The partition includes a tapered plate that is smaller at the top and larger at the bottom. The protrusion is located at the upper end of the tapered plate. The outer wall of the shell is provided with a liquid outlet pipe that communicates with the upper end of the lower side of the tapered plate. A sealing plug for sealing the vent is slidably and sealingly installed inside the protrusion. A connecting rod is provided at the upper end of the sealing plug. The upper end of the rod is provided with a lower turntable, and a return spring is provided between the lower turntable and the protrusion. The lower end of the rotating shaft is provided with an upper turntable. The lower side of the upper turntable and the upper side of the lower turntable are respectively provided with protrusions. When the rotating shaft rotates, it drives the upper turntable to rotate. The lower turntable moves up and down under the action of the upper turntable and the return spring. During the up and down movement of the sealing plug, it periodically seals and unseals the vent hole, so that the ammonia vapor in the evaporation chamber intermittently enters the purification chamber. The ammonia vapor in the purification chamber enters the heating chamber through the inlet one-way valve. The evaporation chamber is provided with a demisting screen.

2. The liquid ammonia evaporator for electronic-grade ammonia water production according to claim 1, characterized in that, The upper end of the protrusion is sealed, and the upper end of the protrusion is provided with a through hole.

3. The liquid ammonia evaporator for electronic-grade ammonia water production according to claim 1, characterized in that, The heating chamber is equipped with several guide plates that match the heating coil and allow the gas entering the heating chamber to flow along the extension direction of the heating coil. The upper end of the shell is equipped with an outlet pipe that communicates with the purification chamber.

4. The liquid ammonia evaporator for electronic-grade ammonia water production according to claim 1, characterized in that, The drive mechanism includes a drive motor. The upper end of the housing is provided with a motor mounting base. The drive motor is fixedly connected to the upper side of the motor mounting base. The output shaft of the drive motor extends into the motor mounting base. The output shaft of the drive motor is connected to the rotating shaft through a coupling.

5. The liquid ammonia evaporator for electronic-grade ammonia water production according to claim 1, characterized in that, The outlet pipe is equipped with a shut-off valve.

6. The liquid ammonia evaporator for electronic-grade ammonia water production according to claim 2, characterized in that, The evaporation chamber has fixed plates on its walls located on the upper and lower sides of the demister screen. A guide rod is provided between the two fixed plates. The frame of the demister screen is guided and installed on the guide rod. Two buffer springs are respectively installed on the guide rod on the upper and lower sides of the demister screen. The two ends of the buffer springs are respectively connected to the fixed plates and the frame of the demister screen. A transmission rod is fixedly connected to the lower end of the sealing plug. A fixing block is provided at the lower end of the transmission rod to push the demister screen downward when the sealing plug moves downward.

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