Multistage digestion reaction system for calcium hydroxide production

Abstract

The application discloses a kind of multistage digestion reaction systems for calcium hydroxide production applied to quicklime digestion processing related field, by setting dynamic material guiding component and flow rate sensor between multistage digester, the conveying speed of calcium hydroxide slurry is monitored in real time, and when the sign of blockage appears, automatically drive the eccentric unit to make the shaped half pipe move, increase the effective caliber of feed inlet, simultaneously utilize the structural dynamic change to exert vibration force to slurry, to quickly dredge pipeline, restore conveying continuity, effectively avoid unplanned shutdown;With inner sealing bush, water vapor sensor and spiral opening warning ring, timely warning and intuitive judgment leakage degree can be realized when leakage occurs, to gain reaction time for maintenance, the overall operation reliability, automation degree and production efficiency of multistage digestion system are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of quicklime digestion and treatment, and particularly to a multi-stage digestion reaction system for calcium hydroxide production. Background Technology

[0002] Calcium hydroxide is an important inorganic alkali material used in environmental protection, medicine, and construction. Its preparation typically uses calcium oxide as a raw material, producing a calcium hydroxide slurry through a digestion reaction. To improve the product's activity and dispersibility, multi-stage digestion reaction systems are widely used in calcium hydroxide production. These systems utilize multi-stage digesters connected in series to sequentially complete pre-digestion, ripening digestion, and other processes, achieving efficient material conversion and complete reaction.

[0003] However, calcium hydroxide slurry is characterized by high viscosity and high solids content, making it prone to clogging in connecting pipes and inlets during the transfer process from one digester to the next. Once clogging occurs, it not only affects the continuity of material transport between digesters but can also cause unplanned shutdowns of the entire production line, severely restricting production efficiency. For example, Chinese utility model patent CN213739207U discloses a multi-stage digestion device for preparing calcium hydroxide.

[0004] To address this issue, Chinese utility model patent CN214829975U discloses a digester for calcium hydroxide production. This digester alleviates material blockage during operation by incorporating dual feed pipes at the inlet and a water spray nozzle for wetting and dispersion. However, both of these solutions focus on preventing blockages in the feeding process of a single digester. They lack effective dynamic intervention methods for addressing blockages that occur during the transport of high-viscosity slurry between digesters via connecting pipelines, and cannot provide real-time adjustment of blockages without interrupting production. Summary of the Invention

[0005] The core of this invention lies in setting up a dynamic material guiding component and a flow rate sensor between multi-stage digesters to monitor the conveying speed of calcium hydroxide slurry in real time, and automatically driving the eccentric unit to move the shaping half-pipe when signs of blockage appear, thereby increasing the effective diameter of the feed inlet. This solves the problem of easy blockage of calcium hydroxide slurry when it is conveyed between two digesters and reduces the impact on the calcium hydroxide production process.

[0006] To solve the above problems, the present invention adopts the following technical solution.

[0007] A multi-stage digestion reaction system for calcium hydroxide production includes a control center, a primary digester, a secondary digester, and a tertiary digester. Each of the primary, secondary, and tertiary digesters is equipped with a spray assembly and a stirring assembly. The primary, secondary, and tertiary digesters are arranged in a stepped configuration. Dynamic material guiding components are installed between the discharge port of the primary digester and the inlet of the secondary digester, and between the discharge port of the secondary digester and the inlet of the tertiary digester. The system also includes two flow rate sensors installed at the outlets of the two dynamic material guiding components. Each dynamic material guiding component includes a guide pipe located between the primary and secondary digesters, two outer lining semi-rings fixedly connected to the outer ends of the guide pipe, and two sets of deflection units installed at the near ends of the two outer lining semi-rings. The flow rate sensors and deflection units are both connected to the control center. Ear plates are fixedly connected to the two near ends of the two outer lining semi-rings, with the two ear plates on the same side facing each other, and the deflection units corresponding to the two ear plates. The upper and lower outer edges of the feed tube are fixedly connected to an upper mounting plate and a lower mounting plate, respectively. Both the upper and lower mounting plates have multiple guide holes. The upper mounting plate is installed at the discharge port of the primary or secondary digester by bolts, and the lower mounting plate is installed at the feed port of the secondary or tertiary digester by bolts, with the bolts passing through the guide holes.

[0008] Furthermore, the cross-sections of both the feed inlet and the guide elongated hole are racetrack-shaped, and their centerlines are parallel. The lateral span of the guide elongated hole is not less than the maximum distance between the lower end edge of the guide tube and the semicircular part of the feed inlet.

[0009] Furthermore, the feed tube includes two shaped half tubes and a deformable layer fixedly connected between the two shaped half tubes. The two ends of the deformable layer extend to the space between the two upper mounting pieces and the two lower mounting pieces, respectively, and are fixedly connected to the upper mounting pieces and the lower mounting pieces.

[0010] Furthermore, the upper end of the shaped semi-tube has a conical structure with a tapered opening at the bottom, and the lower end of the shaped semi-tube has a cylindrical structure. The deformation layer is made of a high-temperature resistant and corrosion-resistant elastic material.

[0011] Furthermore, two rubber rings are fixedly embedded on the annular upper surface formed by the two shaped half-tubes and the deformation layer, with the two rubber rings located on the inner and outer sides of the multiple guide holes, respectively.

[0012] Furthermore, the biasing unit includes an electromagnetic plate, two guide rods fixedly connected to the left and right ends of the electromagnetic plate, and two support columns fixedly connected to the lower end of the guide rods and the upper end of the secondary digester or tertiary digester, respectively. The two guide rods movably pass through the two ear plates.

[0013] Furthermore, both ear plates are made of strong magnetic material, and the electromagnetic plate consists of a three-layer structure. The middle layer of the electromagnetic plate is a magnetic shielding layer, and the left and right layers of the electromagnetic plate are electromagnetic layers. When a positive current flows through the electromagnetic layer, it generates a magnetic attraction force on the ear plate, and when a reverse current flows through the electromagnetic layer, it generates a magnetic repulsion force on the ear plate.

[0014] Optionally, an inner sealing bushing is also provided inside the feed tube. The two ends of the inner sealing bushing pass through the feed inlet and feed outlet respectively and are fixedly connected to the edges of the two. The inner sealing bushing includes a metal mesh layer in the middle, an elastic sealing layer wrapped around the metal mesh layer, and a nylon layer wrapped around the elastic sealing layer.

[0015] Furthermore, a water vapor sensor and an opening warning ring are fixedly installed on the inner and outer walls of the cylindrical surface of the feed tube, respectively. An inlet hole is drilled on the outer wall of the cylindrical surface of the feed tube. The inlet hole corresponds to and communicates with one end of the opening warning ring. A drain hole is drilled on the outer end of the other end of the opening warning ring. In the circumferential direction, the opening warning ring spirals upward from the inlet hole to the drain hole.

[0016] Optionally, the biasing unit includes an inverted U-shaped frame located outside the outer liner semi-ring and an electric push rod fixedly connected between the inverted U-shaped frame and the two ear plates.

[0017] Compared with the prior art, the advantages of this invention are: This solution monitors the delivery speed of calcium hydroxide slurry in real time by installing dynamic feeding components and flow rate sensors between multi-stage digesters. When signs of blockage appear, it automatically drives the eccentric unit to move the shaping half-pipe, increasing the effective diameter of the feed inlet. At the same time, it uses dynamic structural changes to apply vibration force to the slurry, thereby quickly clearing the pipeline and restoring the continuity of delivery, effectively avoiding unplanned downtime. With the addition of an inner sealing bushing, a moisture sensor, and a spiral opening warning ring, it can provide timely warnings and visually assess the degree of leakage in case of leakage, giving time for maintenance. Overall, it significantly improves the operational reliability, automation level, and production efficiency of the multi-stage digester system. Attached Figure Description

[0018] Figure 1 This is a perspective view of the present invention; Figure 2 This is a block diagram of the modules of the present invention; Figure 3 This is a front view of the present invention; Figure 4 This is a perspective view of the feed inlet portion of the secondary digester of the present invention; Figure 5 This is an exploded view of the dynamic material guiding component of the present invention; Figure 6 This is a perspective view of the dynamic material guiding component of the present invention after the internal diameter has been increased; Figure 7This is a comparative schematic diagram showing the dynamic material guiding component of the present invention when the diameter increases on the left, right, and both sides. Figure 8 This is a perspective view of the eccentric unit of the present invention when an electric push rod is used as the driving force. Figure 9 A cross-sectional schematic diagram of the dynamic material guiding component of the present invention with an inner sealing bushing added inside; Figure 10 This is a cross-sectional schematic diagram of the open warning ring portion of the present invention.

[0019] Explanation of the labels in the diagram: 11 Primary digester, 12 Secondary digester, 13 Tertiary digester, 101 Feed inlet, 2 Dynamic feeding assembly, 21 Feed pipe, 211 Shaped half-pipe, 212 Deformation layer, 22 Outer liner half-ring, 231 Support column, 232 Guide rod, 201 Upper mounting plate, 202 Lower mounting plate, 203 Guide elongated hole, 204 Ear plate, 205 Rubber ring, 241 Inverted U-shaped frame, 242 Electric push rod, 3 Electromagnetic plate, 4 Inner sealing bushing, 5 Opening warning ring, 501 Liquid inlet, 502 Liquid outlet. Detailed Implementation

[0020] The technical solutions will now be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention.

[0021] First implementation method: like Figures 1-3 A multi-stage digestion reaction system for calcium hydroxide production includes a control center, a primary digester 11, a secondary digester 12, and a tertiary digester 13. Each of the primary, secondary, and tertiary digesters 11 and 13 is equipped with a spray assembly and a stirring assembly. The primary, secondary, and tertiary digesters 11 and 13 are arranged in a stepped configuration. Dynamic material guiding components 2 are installed between the discharge port of the primary digester 11 and the inlet port 101 of the secondary digester 12, and between the discharge port of the secondary digester 12 and the inlet port of the tertiary digester 13. The system also includes two flow rate sensors installed at the outlets of the two dynamic material guiding components 2. The flow rate sensor is used to monitor the speed at which calcium hydroxide slurry is transported from the previous digester to the next digester. When the speed is lower than the threshold, it indicates that there is a possibility of blockage. Therefore, when a blockage is possible, the control center can control the dynamic feeding assembly 2 to dynamically increase its inner diameter. On the one hand, the increased inner diameter facilitates the passage of calcium hydroxide slurry. On the other hand, as the inner diameter of the dynamic feeding assembly 2 changes continuously, the dynamic feeding assembly 2 itself is in a dynamic state, which can generate a certain vibration force on the slurry inside, thereby increasing the flow rate of the slurry between the two digesters, and thus effectively inhibiting the further development of blockage, making the entire digestion process less susceptible to impact.

[0022] like Figures 4-5 The dynamic material guiding assembly 2 includes a material guiding pipe 21 located between the primary digester 11 and the secondary digester 12, two outer lining semi-rings 22 respectively fixedly connected to the outer ends of the material guiding pipe 21, and two sets of deflection units respectively installed at the close ends of the two outer lining semi-rings 22. The flow rate sensor and the deflection units are both connected to the control center signal. The outer ends of the two close ends of the two outer lining semi-rings 22 are fixedly connected to ear plates 204. The two ear plates 204 on the same side are arranged opposite to each other, and the deflection units are arranged corresponding to the two ear plates 204. The deflection units are used to drive the two fixed semi-pipes 211 of the dynamic material guiding assembly 2 to move away from the center point of the feed inlet 101 along the guide elongated hole 203, thereby continuously increasing the overlapping area between the lower end of the dynamic material guiding assembly 2 and the feed inlet 101, thereby realizing a unilateral increase in the effective feeding area of ​​the feed inlet 101, thereby accelerating the flow of slurry.

[0023] like Figure 6 The deflection unit includes an electromagnetic plate 3, two guide rods 232 fixedly connected to the left and right ends of the electromagnetic plate 3, and two support columns 231 fixedly connected to the lower end of the guide rods 232 and the upper end of the secondary digester 12 or the tertiary digester 13, respectively. The two guide rods 232 respectively movably pass through two ear plates 204. Both ear plates 204 are made of strong magnetic material. The electromagnetic plate 3 consists of a three-layer structure. The middle layer of the electromagnetic plate 3 is a magnetic shielding layer, and the left and right layers of the electromagnetic plate 3 are electromagnetic layers. When a positive current flows through the electromagnetic layers, it generates a magnetic attraction force on the ear plates 204. When a reverse current flows through the electromagnetic layers, it generates a magnetic repulsion force on the ear plates 204. Under normal circumstances, the two electromagnetic layers can be controlled to simultaneously receive a positive current, so that they simultaneously attract the corresponding ear plates 204, thereby limiting the two shaping half tubes 211 from getting close to each other, thus maintaining the normal feeding path; Figure 7 When the feeding speed slows down and blockage may occur, the electromagnetic layer on one side can be controlled to pass a reverse current, which will generate a magnetic repulsion force on the ear plate 204 on the corresponding side, thereby pushing the guide tube 21 on the corresponding side away from the center, so that the feed port 101 expands its exposure range on one side and increases its diameter on one side. Correspondingly, controlling the electromagnetic layer on the other side to pass the current can increase the diameter on the other side of the feed port 101. If both electromagnetic layers are energized at the same time, the diameters on both sides can be increased at the same time.

[0024] The feed tube 21 includes two shaped half tubes 211 and a deformable layer 212 fixedly connected between the two shaped half tubes 211. The two ends of the deformable layer 212 extend between the two upper mounting plates 201 and the two lower mounting plates 202 respectively and are fixedly connected to the upper mounting plates 201 and the lower mounting plates 202. The upper end of the shaped half tube 211 is a conical structure with a tapered opening at the bottom, and the lower end of the shaped half tube 211 is a cylindrical structure. The deformable layer 212 is made of a high-temperature resistant and corrosion-resistant elastic material. When the eccentric unit is working, the shaped half tube 211 moves with force, while the deformable layer 212 is stretched and deformed to adapt to the change in diameter of the feed tube 21. At the same time, the entire feed tube 21 remains closed after being subjected to force, which facilitates the stable feeding of slurry.

[0025] like Figure 5 The upper and lower outer edges of the feed tube 21 are respectively fixedly connected to an upper mounting plate 201 and a lower mounting plate 202. Both the upper and lower mounting plates 201 and 202 have multiple guide holes 203. The upper mounting plate 201 is bolted to the discharge port of the primary digester 11 or the secondary digester 12, and the lower mounting plate 202 is bolted to the inlet 101 of the secondary digester 12 or the tertiary digester 13. The bolts penetrate the guide holes 203. The cross-sections of the inlet 101 and the guide holes 203 are... Both surfaces are racetrack-shaped, and their centerlines are parallel, allowing the two fixed half-tubes 211 to move along them under the drive of the two eccentric units. This facilitates the dynamic diameter change of the guide tube 21. The lateral span of the guide elongated hole 203 is not less than the maximum distance between the lower end edge of the guide tube 21 and the semicircular part of the feed inlet 101. This effectively ensures that when the guide tube 21 expands along the guide elongated hole 203, the feed inlet 101 can be fully exposed, so that the feed of the subsequent digester can reach its maximum during the dynamic change of the dynamic guide assembly 2.

[0026] Two rubber rings 205 are fixedly embedded on the annular upper surface formed by the two shaping half tubes 211 and the deformation layer 212. The two rubber rings 205 are located on the inner and outer sides of the multiple guide holes 203 respectively. By setting the rubber rings 205, the sealing between the dynamic material guiding component 2 and the discharge port and the edge of the inlet 101 can be effectively guaranteed, so that the slurry inside the shaping half tube 211 is not easy to leak out when it moves along the guide holes 203, thus ensuring the stable progress of the digestion process.

[0027] Second implementation method: Compared to the first implementation method, this implementation method uses a different biasing unit, as detailed below: like Figure 8The biasing unit includes an inverted U-shaped frame 241 located outside the outer liner semi-ring 22 and an electric push rod 242 fixedly connected between the inverted U-shaped frame 241 and the two ear plates 204. When it is necessary to control the diameter of the guide tube 21 to increase on one or both sides, so as to change the effective feed port diameter of the feed port 101, the control center can directly control the electric push rod 242 to extend or shorten.

[0028] Compared to the first implementation method, the electric push rod 242 provides more direct control over the changes in the guide tube 21. However, with multiple electric push rods 242, the synchronization may be deviated. Therefore, in specific implementation, a suitable deflection unit can be selected according to actual needs.

[0029] The third implementation method: This embodiment adds an inner sealing bushing 4 and a water vapor sensor to the first or second embodiment, while the rest remains the same as the first or second embodiment.

[0030] like Figures 9-10 The feed tube 21 is also provided with an inner sealing bushing 4. The two ends of the inner sealing bushing 4 pass through the feed inlet and feed outlet 101 respectively and are fixedly connected to the edges of the two. The inner sealing bushing 4 includes a metal mesh layer in the middle, an elastic sealing layer wrapped around the metal mesh layer, and a nylon layer wrapped around the elastic sealing layer. The surface of the nylon layer is coated with LINE-X coating, so that the inner sealing bushing 4 has good wear resistance and tensile strength, making it less likely to be worn by the slurry when it is carrying the slurry.

[0031] A water vapor sensor and an opening warning ring 5 are fixedly installed on the inner and outer walls of the cylindrical surface of the feed tube 21, respectively. The opening warning ring 5 is a hollow structure. An inlet hole 501 is drilled on the outer wall of the cylindrical surface of the feed tube 21. The inlet hole 501 corresponds to and communicates with one end of the opening warning ring 5. A drain hole 502 is drilled on the outer end of the other end of the opening warning ring 5. In the circumferential direction, the opening warning ring 5 spirals upward from the inlet hole 501 to the drain hole 502. When the inner sealing bushing 4 is damaged and leakage occurs, the high water content slurry that seeps out falls to the bottom. This part of the water will enter the opening warning ring 5 along the inlet hole 501. At this time, the liquid level will spiral upward, and then overflow from the drain hole 502. This means that it takes a certain amount of time from the occurrence of leakage to the leakage outside the dynamic feed assembly 2. This process provides the staff with a certain reaction preparation time from obtaining the leakage signal of the water vapor sensor to on-site maintenance.

[0032] By setting the inner sealing bushing 4 inside the dynamic material guiding component 2, the inner sealing bushing 4 can complete the conveying of slurry between the front and rear digesters. The dynamic material guiding component 2 mainly undertakes the function of shaping the inner sealing bushing 4. During the movement of the slurry, it can press the inner sealing bushing 4, making it adhere to the surface of the dynamic material guiding component 2, so that the main material guiding space is still consistent with the internal space of the dynamic material guiding component 2. At this time, since the inner sealing bushing 4 no longer undertakes the sealing function, the rubber ring 205 can be eliminated in this embodiment, or the contact area between the rubber ring 205 and the primary digester 11, the secondary digester 12, or the tertiary digester 13 can be reduced, so that the frictional resistance encountered by the eccentric unit when driving the two shaped half tubes 211 to move is smaller.

[0033] In addition, with the water vapor sensor, if the inner sealing bushing 4 is damaged, causing some slurry to overflow (because water has stronger fluidity, its main component is water, not the particulate matter in the slurry), it will first flow into the dynamic material guiding component 2. At this time, the water vapor sensor inside can detect this information in time and provide an early warning to the staff, so that the staff can arrive at the site in time for maintenance. Some of the water that falls into the dynamic material guiding component 2 will accumulate at the bottom and enter the opening warning ring 5 along the liquid inlet hole 501. When the staff is maintaining the site, they can judge whether the amount of leakage is small or large based on whether the water is discharged along the liquid outlet hole 502, so that they can take more targeted maintenance measures.

[0034] The above description is merely a preferred embodiment of the present invention; it encompasses all the protection scope of the present invention. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solutions and improved concepts of the present invention, should be covered within the protection scope of the present invention.

Claims

1. A multi-stage digestion reaction system for calcium hydroxide production, comprising a control center, a primary digester (11), a secondary digester (12), and a tertiary digester (13), wherein each of the primary digester (11), the secondary digester (12), and the tertiary digester (13) is equipped with a spray assembly and a stirring assembly, characterized in that: The primary digester (11), secondary digester (12), and tertiary digester (13) are arranged in a stepped configuration. Dynamic material guiding components (2) are installed between the discharge port of the primary digester (11) and the inlet (101) of the secondary digester (12), and between the discharge port of the secondary digester (12) and the inlet of the tertiary digester (13). The system also includes two flow rate sensors installed at the outlets of the two dynamic material guiding components (2). The dynamic material guiding components (2) include those located at the outlets of the primary digester (11) and the secondary digester (13). The feed tube (21) between the digesters (12), two outer lining half-rings (22) respectively fixedly connected to the outer ends of the feed tube (21), and two sets of deflection units respectively installed at the close ends of the two outer lining half-rings (22). The flow rate sensor and the deflection unit are both connected to the control center signal. The two close ends of the two outer lining half-rings (22) are fixedly connected to ear plates (204). The two ear plates (204) on the same side are arranged opposite to each other, and the deflection unit is arranged corresponding to the two ear plates (204). The upper and lower outer edges of the feed tube (21) are fixedly connected to an upper mounting plate (201) and a lower mounting plate (202), respectively. Both the upper mounting plate (201) and the lower mounting plate (202) have multiple guide holes (203). The upper mounting plate (201) is installed at the discharge port of the primary digester (11) or the secondary digester (12) by bolts. The lower mounting plate (202) is installed at the feed inlet (101) of the secondary digester (12) or the tertiary digester (13) by bolts, and the bolts pass through the guide holes (203).

2. The multi-stage digestion reaction system for calcium hydroxide production according to claim 1, characterized in that: The cross-sections of the feed inlet (101) and the guide elongated hole (203) are both racetrack-shaped, and their centerlines are parallel. The lateral span of the guide elongated hole (203) is not less than the maximum distance between the lower end edge of the guide tube (21) and the semicircular part of the feed inlet (101).

3. The multi-stage digestion reaction system for calcium hydroxide production according to claim 1, characterized in that: The feed tube (21) includes two shaped half tubes (211) and a deformable layer (212) fixedly connected between the two shaped half tubes (211). The two ends of the deformable layer (212) extend to the space between the two upper mounting pieces (201) and the two lower mounting pieces (202) and are fixedly connected to the upper mounting pieces (201) and the lower mounting pieces (202).

4. The multi-stage digestion reaction system for calcium hydroxide production according to claim 3, characterized in that: The upper end of the shaped half tube (211) is a conical structure with a tapered opening at the bottom, and the lower end of the shaped half tube (211) is a cylindrical structure. The deformation layer (212) is made of a high-temperature resistant and corrosion-resistant elastic material.

5. A multi-stage digestion reaction system for calcium hydroxide production according to claim 4, characterized in that: Two rubber rings (205) are fixedly embedded on the annular upper surface formed by the two shaped half tubes (211) and the deformed layer (212). The two rubber rings (205) are located on the inner and outer sides of the multiple guide holes (203).

6. A multi-stage digestion reaction system for calcium hydroxide production according to claim 5, characterized in that: The biasing unit includes an electromagnetic plate (3), two guide rods (232) fixedly connected to the left and right ends of the electromagnetic plate (3), and two support columns (231) fixedly connected to the lower end of the guide rods (232) and the upper end of the secondary digester (12) or the tertiary digester (13), respectively. The two guide rods (232) respectively movably pass through the two ear plates (204).

7. A multi-stage digestion reaction system for calcium hydroxide production according to claim 6, characterized in that: Both ear plates (204) are made of strong magnetic material. The electromagnetic plate (3) consists of a three-layer structure. The middle layer of the electromagnetic plate (3) is a magnetic shielding layer. The left and right layers of the electromagnetic plate (3) are electromagnetic layers. When the electromagnetic layer carries a positive current, it generates a magnetic attraction force on the ear plate (204). When the electromagnetic layer carries a reverse current, it generates a magnetic repulsion force on the ear plate (204).

8. A multi-stage digestion reaction system for calcium hydroxide production according to claim 7, characterized in that: The feed tube (21) is also provided with an inner sealing bushing (4). The two ends of the inner sealing bushing (4) respectively pass through the feed inlet and feed outlet (101) and are fixedly connected to the edges of the two. The inner sealing bushing (4) includes a metal mesh layer in the middle, an elastic sealing layer wrapped around the metal mesh layer, and a nylon layer wrapped around the elastic sealing layer.

9. A multi-stage digestion reaction system for calcium hydroxide production according to claim 8, characterized in that: A water vapor sensor and an opening warning ring (5) are fixedly installed on the inner and outer walls of the cylindrical surface of the feed tube (21). An inlet hole (501) is drilled on the outer wall of the cylindrical surface of the feed tube (21). The inlet hole (501) corresponds to and communicates with one end of the opening warning ring (5). A drain hole (502) is drilled on the outer end of the other end of the opening warning ring (5). In the circumferential direction, the opening warning ring (5) spirals upward from the inlet hole (501) to the drain hole (502).

10. A multi-stage digestion reaction system for calcium hydroxide production according to claim 5, characterized in that: The biasing unit includes an inverted U-shaped frame (241) located outside the outer liner half-ring (22) and an electric push rod (242) fixedly connected between the inverted U-shaped frame (241) and the two ear plates (204).

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