Urea production device

Abstract

The invention relates to the technical field of urea production, in particular to a urea production device. Comprising a mixing tank, a feeding hopper, a stirring device, a liquid inlet pipe and a liquid discharging pipe, an inner cylinder is arranged in the mixing tank and divides the mixing tank into an inner mixing bin for storing premixed liquid and an outer mixing bin for storing raw materials to be mixed from inside to outside, a filter screen plate is arranged above the inner cylinder, and small-particle raw materials are evenly dispersed in the inner mixing bin through the filter screen plate; and the large-particle raw materials are guided into the external mixing bin. In the liquid separation stage, water waves generated by vortex rotation are used for driving the floating plate to drive the drainage plate to float up and down in the premixed liquid, so that vortex outer ring solutions with different depths are guided to the axis, and the mixing degree of the solutions in the horizontal direction is enhanced; the floating plate is used for raising the vortex outer ring solution in an inclined manner, so that gravitational potential energy is used for impacting the rear part of the drainage plate, the local concentration difference is further broken, and the solution is promoted to reach a more uniform mixing state.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of urea production, in particular, to a urea production device. BACKGROUND

[0002] The mixing device for producing vehicle urea solution is a device for mixing high-purity urea and deionized water in a certain proportion, which is widely used in the production of vehicle urea solution used in SCR (selective catalytic reduction) system, which helps to reduce nitrogen oxides emitted by vehicles and meets environmental protection requirements.

[0003] The patent CN120079302A discloses a mixing device for producing vehicle urea solution, which belongs to the technical field of vehicle urea solution processing. The mixing device includes a mixing tank, a raw material barrel fixed on the top of the mixing tank through a support, a liquid input pipe fixed on the side wall of the raw material barrel, a conical inner wall bottom of the raw material barrel, and two feed pipes fixed between the top of the mixing tank and the bottom of the raw material barrel. The pretreatment device is provided to screen the urea raw material with the cooperation of the stirring blade rod, the flower disc, the arc block ring, and the contact rod driving the conical mesh cylinder. The smaller particles of urea will directly fall into the soft water, and the grinding teeth of the grinding roller and the conical mesh cylinder will grind and crush the larger particles of urea. The ground and crushed urea will fall into the soft water. By directly feeding the smaller particles of urea and feeding the larger particles of urea after grinding and crushing, the crushing time is reduced.

[0004] Due to the vortex formed in the solution during the stirring process of the stirring plate, the vortex causes the urea particles to gather in the outer circle, resulting in differences in urea concentration in different areas of the solution. The urea concentration in the central area is lower, while the urea concentration in the outer circle area is too high, which cannot form a uniform mixed solution. Moreover, in the prior art, when adding urea particles, a hole is usually cut on the urea packaging bag, and urea particles are added into the solution while stirring, which causes a large amount of urea particles to fall into the same area and cannot uniformly cover the solution, reducing the mixing efficiency. SUMMARY

[0005] The present application provides a urea production device, which uses water waves generated by vortex rotation to drive the floating plate to drive the drainage plate to float up and down in the pre-mixed liquid, and to guide the vortex outer circle solution at different depths to the axis, thereby enhancing the mixing degree of the solution in the horizontal direction. In the mixing stage, the floating plate jumps up and raises the height of the vortex outer circle solution by tilting, so as to use the gravitational potential energy to impact the rear of the drainage plate, thereby solving the problems raised in the above background technology, i.e.: To achieve the above object, the urea production device comprises a mixing tank, a feeding hopper, a stirring device, a liquid inlet pipe and a liquid outlet pipe, an inner cylinder is arranged in the mixing tank, the inner cylinder divides the mixing tank into an inner mixing chamber for storing pre-mixed liquid and an outer mixing chamber for storing raw materials to be mixed from inside to outside, a filter screen is arranged above the inner cylinder, the filter screen uniformly disperses small-particle raw materials in the inner mixing chamber, and large-particle raw materials are guided into the outer mixing chamber; The bottom of the inner mixing chamber is provided with a flow limiting mechanism, and a flow disturbing mechanism is symmetrically arranged on the inner side, in the liquid separation stage, the flow limiting mechanism is responsible for releasing the original liquid in the inner mixing chamber, and an impact is formed on the raw materials to be mixed in the outer mixing chamber by means of the pressure of the original liquid in the inner mixing chamber, so as to realize solid-liquid mixing, and the flow disturbing mechanism moves the solution at the inner wall in the inner cylinder to the axis by floating up and down; in the liquid mixing stage, the flow limiting mechanism separates the inner mixing chamber from the outer mixing chamber, and the flow disturbing mechanism forces the solution at the inner wall in the inner cylinder to jump up and hit the rear solution in an inclined manner.

[0006] An outer flow port is symmetrically arranged below the inner wall of the inner cylinder and communicates the inner mixing chamber with the outer mixing chamber, and the outer flow port guides the pre-mixed liquid into the outer mixing chamber.

[0007] The flow limiting mechanism comprises a flow limiting plate which is arranged on the inner wall of the inner cylinder and corresponds to the flow limiting plate, in the normal state, the flow limiting plate is in the overlapping state with the outer flow port, and the flow limiting plate is used for plugging the outer flow port to limit the pre-mixed liquid from flowing out, and in the liquid separation stage, the flow limiting plate is in the dislocation state with the outer flow port.

[0008] Further, the flow disturbing mechanism comprises a floating plate floating on the liquid surface of the pre-mixed liquid, and a flow guide plate rotationally connected to the bottom of the floating plate, the floating plate uses the waves formed by the liquid surface of the pre-mixed liquid as power to drive the flow guide plate to move up and down in the pre-mixed liquid, so as to disturb the pre-mixed liquid at different depths.

[0009] One side of the flow guide plate is slidingly connected with a guide rail fixed to the inner wall of the inner cylinder, the other side extends to the axis, and the end portion is inclined outward to form an outwardly inclined end, the outwardly inclined end is used for guiding the solution at the inner wall in the inner cylinder to the inner side, so that the solution at the outer circle of the vortex is mixed with the solution in the middle of the vortex.

[0010] The flow limiting mechanism further comprises a lever fixedly arranged on the inner side of the flow limiting plate, and the floating plate is located on the rotation path of the lever, the lever is used for rotating the floating plate and blocking the floating plate, so that one end of the floating plate is lifted from the liquid surface of the pre-mixed liquid, and the other end is immersed in the pre-mixed liquid.

[0011] Compared with the prior art, the present application has the following advantages: 1. In the separation stage, the water waves generated by the vortex rotation drive the floating plate to move up and down in the premixed liquid, allowing the solution in the outer ring of the vortex at different depths to be guided towards the axis, thus enhancing the mixing degree of the solution in the horizontal direction. Furthermore, in the mixing stage, the floating plate tilts to raise the solution in the outer ring of the vortex to a higher height, using gravitational potential energy to impact the back of the guide plate, further breaking down local concentration differences and promoting a more uniform mixing state of the solution.

[0012] 2. During feeding, the filter screen moves up and down to control the amount of material fed, achieving precise feeding and avoiding large-scale feeding at one time. At the same time, the raw materials are sorted by the filter screen. Small particles slide along the filter screen and are evenly dispersed in the solution, while large particles are guided to the external mixing chamber for storage, thereby preventing uneven mixing caused by agglomeration of raw materials. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a front view of the internal structure of the mixing tank and inner cylinder of the present invention (cut section). Figure 3 This is a right-hand view of the cross-sectional internal structure of the mixing tank and inner cylinder of the present invention. Figure 4 This is a schematic diagram of the exploded structure of the feed hopper and inner cylinder of the present invention; Figure 5 This is a schematic diagram of the filter plate of the present invention blocking the feed hopper; Figure 6 This is a left view of a partial cross-sectional structure of the mixing tank and inner cylinder of the present invention; Figure 7 This is a top view of the inner cylinder, floating plate, and diversion plate structure of the present invention; Figure 8 This is a schematic diagram of the connection structure between the lever and the flow limiting plate of the present invention; Figure 9 For the present invention Figure 8 Enlarged structural diagram at point A in the diagram; Figure 10 This is a schematic diagram illustrating the principle of how the lever drives the floating plate to rotate in this invention. Figure 11 This is a schematic diagram of the tilting structure of the floating plate of the present invention.

[0014] The meanings of the labels in the diagram are as follows: 100. Mixing tank; 101. Feed hopper; 102. Stirring device; 103. Liquid inlet pipe; 104. Liquid outlet pipe; 105. Hydraulic rod; 110. Inner cylinder; 111. Inner mixing chamber; 112. Outer mixing chamber; 113. Outflow port; 114. Circulation pump; 120. Flow limiting mechanism; 121. Flow limiting plate; 122. Toggle lever; 123. Horizontal plate; 124. Motor; 130. Floating plate; 131. Diversion plate; 132. Guide rail; 133. First stop block; 134. Second stop block; 140. Filter screen. Detailed Implementation

[0015] 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.

[0016] During the stirring process, eddies are formed in the solution, causing urea particles to converge towards the outer edge. This results in differences in urea concentration in different areas of the solution. The central area has a lower urea concentration, while the outer area has an excessively high concentration, making it impossible to form a homogeneous mixture. Furthermore, in existing technologies, when adding urea particles, a small opening is typically made in the urea packaging bag, allowing the particles to fall into the solution while stirring. This results in a large number of urea particles falling into the same area, failing to evenly cover the solution and reducing mixing efficiency.

[0017] In view of the above-mentioned problems, the present invention provides a urea production apparatus, see [link to apparatus]. Figures 1-3 As shown, the system includes a mixing tank 100, a feed hopper 101, a stirring device 102, a liquid inlet pipe 103, and a liquid outlet pipe 104. An inner cylinder 110 is provided inside the mixing tank 100. The inner cylinder 110 divides the mixing tank 100 from the inside to the outside into an inner mixing chamber 111 for storing premixed liquid and an outer mixing chamber 112 for storing raw materials to be mixed. Before urea production, the raw liquid is first transported into the inner cylinder 110 through the liquid inlet pipe 103, while the liquid outlet pipe 104 is closed at this time. As the raw liquid is injected, the liquid level in the inner cylinder 110 rises. When the raw liquid in the inner cylinder 110 reaches the set liquid level, the injection stops. Then, urea granules are added to the raw liquid for mixing. It should be understood that when small particles are mixed with the original liquid in the inner cylinder 110, the resulting solution is a premixed solution, while the large particles that fall into the outer mixing chamber 112 are the raw materials to be mixed.

[0018] Urea granules are fed into the mixing tank 100 through the feed hopper 101. A filter plate 140 is installed above the inner cylinder 110, and the filter plate 140 is located between the inner cylinder 110 and the feed hopper 101. The filter plate 140 evenly disperses small granular raw materials in the inner mixing chamber 111, and guides large granular raw materials to the outer mixing chamber 112. In this way, for some urea granules that can pass through the filter plate 140, they are dispersed from the top of the filter plate 140 along the inclined surface to the end. The small granules that pass through the filter plate 140 can be evenly dispersed onto the original liquid inside the inner cylinder 110 for mixing. Secondly, if clumps of urea particles or large individual particles cannot pass through the filter screen 140, they are guided through the filter screen 140 to the outer mixing chamber 112 for storage. Since the end of the filter screen 140 is at a certain height from the bottom wall of the outer mixing chamber 112, the clumps of urea particles rolling off the filter screen 140 have kinetic and potential energy. When they come into contact with the bottom wall of the outer mixing chamber 112, they collide, which helps to break up the clumps of urea particles, thereby improving the mixing effect with the premixed liquid in the later stage.

[0019] Combination Figure 4 and Figure 5 As shown, when adding raw materials into the feed hopper 101, the top of the feed hopper 101 is wide-mouthed to facilitate the addition of raw materials. A hydraulic rod 105 is fixedly installed on the top of the filter screen plate 140. The hydraulic rod 105 is responsible for controlling the height of the filter screen plate 140. During the stopping phase, the hydraulic rod 105 drives the filter screen plate 140 to move upward, and the filter screen plate 140 is attached to the bottom of the feed hopper 101 to restrict the discharge of raw materials. During the feeding phase, the hydraulic rod 105 pushes the filter screen plate 140 downward, and the filter screen plate 140 is away from the bottom of the feed hopper 101. There is a material discharge channel between the bottom of the feed hopper 101 and the filter screen plate 140 for the flow of raw materials. In this way, the raw materials stored in the feed hopper 101 roll down onto the filter screen plate 140 through the material discharge channel and are screened by the filter screen plate 140, so that large and small urea particles fall into the corresponding areas respectively, thereby achieving the purpose of quantitative feeding and avoiding the phenomenon of excessive urea particles being mixed in at one time, resulting in excessively high local solution concentration.

[0020] Return to Figure 2 and Figure 3 As shown, a flow-limiting mechanism 120 is installed at the bottom of the inner mixing chamber 111, and a flow-turbulence mechanism is symmetrically arranged on the inner side. During the liquid separation stage, the flow-limiting mechanism 120 is responsible for releasing the original liquid in the inner mixing chamber 111. The pressure of the original liquid in the inner mixing chamber 111 impacts the raw materials to be mixed in the outer mixing chamber 112 to achieve solid-liquid mixing. The flow-turbulence mechanism moves the solution attached to the wall of the inner cylinder 110 towards the axis by floating up and down. During the liquid mixing stage, the flow-limiting mechanism 120 separates the inner mixing chamber 111 from the outer mixing chamber 112, and the flow-turbulence mechanism forces the solution attached to the wall of the inner cylinder 110 to jump up and smash into the solution behind it by tilting. The specific principle is as follows: First, when the premixed liquid in the inner cylinder 110 is fully mixed, the next liquid separation stage begins. That is, a portion of the premixed liquid in the inner cylinder 110 is diverted to the outer mixing chamber 112, so that the separated premixed liquid can be mixed with the raw materials to be mixed. During the mixing process, an outflow port 113 is symmetrically opened at the bottom of the inner wall of the inner cylinder 110, connecting the inner mixing chamber 111 and the outer mixing chamber 112. The outflow port 113 guides the premixed liquid into the outer mixing chamber 112. Finally, the liquid levels in the inner mixing chamber 111 and the outer mixing chamber 112 are maintained at the same height. During this process, since the initial liquid level of the premixed liquid is D1, the liquid level in this state has corresponding gravitational potential energy. During the liquid separation, the gravitational potential energy of the premixed liquid is converted into kinetic energy to impact the raw materials to be mixed, so that the premixed liquid can be further dispersed from the raw materials to be mixed, thereby improving the mixing effect between the premixed liquid and the raw materials to be mixed.

[0021] Furthermore, the principle of the premixed liquid flowing from the inner mixing chamber 111 to the outer mixing chamber 112 is as follows: The specific structure of the flow limiting mechanism 120 is described below. The flow limiting mechanism 120 includes a flow limiting plate 121 that is attached to the inner wall of the inner cylinder 110 and corresponds to the flow limiting plate 121. Under normal conditions, the flow limiting plate 121 and the outer outlet 113 are in an overlapping state. The flow limiting plate 121 is used to block the outer outlet 113 and restrict the flow of the premixed liquid. During the liquid separation stage, the flow limiting plate 121 and the outer outlet 113 are in a misaligned state. On the other hand, a horizontal plate 123 is fixedly connected between the two flow-limiting plates 121, and the output shaft of the motor 124 is fixedly connected to the middle of the horizontal plate 123. The motor 124 is located at the bottom of the mixing tank 100. In this way, the raw liquid and small granular urea are mixed by the stirring device 102. After mixing for a period of time, a premixed liquid is formed. The motor 124 is started to drive the horizontal plate 123 to rotate, and the flow-limiting plate 121 is misaligned with the outflow port 113, so that the outflow port 113 is open. The premixed liquid flows into the outer mixing chamber 112 and mixes with the raw materials to be mixed until the liquid levels in the inner mixing chamber 111 and the outer mixing chamber 112 are maintained in a stable state (reference). Figure 6 (Mid-liquid level depth D2).

[0022] When the amount of premixed liquid in the inner mixing chamber 111 decreases, the agitator can play a more effective role in the premixed liquid. The shear force and circulating flow generated by the rotation of the agitator can cover all parts of the premixed liquid, allowing the particles and molecules in the premixed liquid to collide and mix with each other more frequently, reducing the probability of dead zones in the mixing.

[0023] That is, during feeding, the filter plate 140 controls the amount of material fed by moving up and down, so as to achieve precise feeding and avoid large-scale feeding at one time. At the same time, the raw materials are sorted by the filter plate 140. Small particles slide along the filter plate 140 and are evenly scattered in the solution, while large particles are guided to the external mixing chamber 112 for storage, thereby preventing the problem of uneven mixing caused by the agglomeration of raw materials.

[0024] Furthermore, as the premixed liquid level decreases, the turbulence-inducing mechanism also moves downwards simultaneously. Therefore, combined with... Figure 6 , Figure 7 , Figure 8 , Figure 9 As shown below, the turbulence mechanism includes a floating plate 130 floating on the surface of the premixed liquid and a guide plate 131 rotatably connected to the bottom of the floating plate 130. During the process of the premixed liquid level dropping and the stirring device 102 agitating, a vortex is formed in the inner cylinder 110. Since the solution in the outer ring of the vortex is unstable and easily forms waves, the floating plate 130 uses the waves formed on the surface of the premixed liquid as power to drive the guide plate 131 to move up and down in the premixed liquid to turbulent the premixed liquid at different depths.

[0025] Next, a guide rail 132 fixed to the inner wall of the inner cylinder 110 is slidably connected to one side of the guide plate 131, and extends towards the axis on the other side, with its end inclined outward to form an outward-curved end. During the counterclockwise rotation of the premixed liquid, the rotating premixed liquid collides with the guide plate 131, breaking the original state of the rotating premixed liquid, thus intercepting and disturbing it. Simultaneously, this outward-curved end is used to guide the solution attached to the inner wall of the inner cylinder 110 inward, allowing the solution at the outer ring of the vortex to mix with the solution in the middle of the vortex, improving the mixing effect. Combined with... Figure 10 , Figure 11 As shown, the flow limiting mechanism 120 also includes a lever 122 fixedly disposed inside the flow limiting plate 121. The floating plate 130 is located on the rotation path of the lever 122. The lever 122 is used to rotate the floating plate 130 and to block the floating plate 130, causing one end of the floating plate 130 to rise from the surface of the premixed liquid and the other end to be submerged in the premixed liquid. In specific operation: during the mixing stage, a circulation pump 114 is installed in the outer mixing chamber 112 (see reference). Figure 6 As shown), the suction pipe of the circulating pump 114 extends into the bottom of the outer mixing chamber 112, and the delivery pipe is connected to the inner mixing chamber 111. Then, the flow limiting plate 121 rotates to coincide with the outflow port 113. In this way, when the mixed liquid in the outer mixing chamber 112 is drawn into the inner mixing chamber 111, the solution in the inner mixing chamber 111 is prevented from flowing back into the outer mixing chamber 112. Therefore, the circulating pump 114 is responsible for pumping the mixture in the outer mixing chamber 112 into the inner mixing chamber 111. The liquid level in the inner mixing chamber 111 rises, and the guide plate 131 moves upward along the guide rail 132. The mixture pumped into the inner mixing chamber 111 is mixed with the premixed liquid in the inner mixing chamber 111. With the stirring action of the stirring device 102, the two mixtures can be fully and evenly mixed. Furthermore, as the circulating pump 114 injects from the top of the liquid surface of D2, the liquid level of the mixed liquid in the inner mixing chamber 111 gradually rises. Then, the solution in the outer mixing chamber 112 will be mixed into the inner mixing chamber 111 under the stirring action of the stirring device 102. This allows the two solutions to be mixed more evenly and improves the mixing effect.

[0026] Secondly, when the outflow port 113 is blocked, the lever 122 causes the floating plate 130 to rotate clockwise, so that the right end of the floating plate 130 is submerged in the solution and the left end is tilted upward. In order to prevent the floating plate 130 from rotating in the opposite direction when the lever 122 causes the floating plate 130 to rotate, a first stop block 133 and a second stop block 134 are respectively provided on both sides of the rotating connection between the floating plate 130 and the guide plate 131. The first stop block 133 and the second stop block 134 are both fixed to the floating plate 130, and the first stop block 133 is close to the rotating connection, while the second stop block 134 is far away from the rotating connection. When the lever 122 moves the floating plate 130 clockwise, the second stop 134 is longer than the first stop 133. When the lever 122 approaches the floating plate 130, it moves the floating plate 130. At this time, the second stop 134 is used to abut against the water-facing surface of the diversion plate 131 to limit the excessive rotation of the floating plate 130, while the first stop 133 is used to abut against the water-reverse surface of the diversion plate 131 to limit the reverse rotation of the floating plate 130, preventing the floating plate 130 from rotating counterclockwise due to liquid surface movement. As the rotation amplitude of the lever 122 increases, when the flow-limiting plate 121 blocks the outflow port 113, the second stop 134 is in contact with the water-facing surface of the diversion plate 131, and the water-facing side of the floating plate 130 ( Figure 11 The right side of the water sinks while the back side rises. This, combined with the rotation of the premixed liquid, causes the premixed liquid to slide in from the sinking end and detach from the rising end. The rising water flow then impacts the solution behind it, improving the mixing effect and ensuring a uniform concentration distribution.

[0027] In summary, during the separation stage, the water waves generated by the vortex rotation drive the floating plate 130 to move the guide plate 131 up and down in the premixed liquid, allowing the solution in the outer ring of the vortex at different depths to be guided towards the axis, thus enhancing the mixing degree of the solution in the horizontal direction. Furthermore, during the mixing stage, the floating plate 130 tilts to raise the height of the solution in the outer ring of the vortex, using gravitational potential energy to impact the rear of the guide plate 131, further breaking down local concentration differences and promoting a more uniform mixing state of the solution.

[0028] Finally, after the solution in the inner cylinder 110 has been mixed, the solution is discharged from the drain pipe 104.

[0029] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A urea production apparatus, comprising a mixing tank (100), a feeding hopper (101), a stirring device (102), a liquid inlet pipe (103), and a liquid outlet pipe (104), characterized in that: An inner cylinder (110) is provided inside the mixing tank (100). The inner cylinder (110) divides the mixing tank (100) from the inside to the outside into an inner mixing chamber (111) for storing premixed liquid and an outer mixing chamber (112) for storing raw materials to be mixed. A filter plate (140) is provided above the inner cylinder (110). The filter plate (140) evenly disperses small particles of raw materials in the inner mixing chamber (111) and guides large particles of raw materials to the outer mixing chamber (112). The bottom of the inner mixing chamber (111) is provided with a flow limiting mechanism (120), and a turbulence turbulence mechanism is symmetrically arranged on the inner side. During the liquid separation stage, the flow limiting mechanism (120) is responsible for releasing the original liquid in the inner mixing chamber (111). The pressure of the original liquid in the inner mixing chamber (111) is used to impact the raw materials to be mixed in the outer mixing chamber (112) to achieve solid-liquid mixing. The turbulence turbulence mechanism moves the solution attached to the wall of the inner cylinder (110) towards the axis by floating up and down. During the liquid mixing stage, the flow limiting mechanism (120) separates the inner mixing chamber (111) from the outer mixing chamber (112). The turbulence turbulence mechanism forces the solution attached to the wall of the inner cylinder (110) to jump up and smash the solution behind it in an inclined manner.

2. The urea production apparatus according to claim 1, characterized in that: A hydraulic rod (105) is fixedly installed on the top of the filter screen plate (140). The hydraulic rod (105) is responsible for controlling the height of the filter screen plate (140). During the material stop stage, the filter screen plate (140) is attached to the bottom of the feed hopper (101) to restrict the discharge of raw materials. During the material injection stage, the filter screen plate (140) is away from the bottom of the feed hopper (101). There is a material discharge channel between the bottom of the feed hopper (101) and the filter screen plate (140) for the flow of raw materials.

3. The urea production apparatus according to claim 1, characterized in that: An outflow port (113) is symmetrically provided below the inner wall of the inner cylinder (110) to connect the inner mixing chamber (111) and the outer mixing chamber (112). The outflow port (113) guides the premixed liquid into the outer mixing chamber (112).

4. The urea production apparatus according to claim 3, characterized in that: The flow limiting mechanism (120) includes a flow limiting plate (121) that is fitted to the inner wall of the inner cylinder (110) and corresponds to the flow limiting plate (121). Under normal conditions, the flow limiting plate (121) and the outflow port (113) are in an overlapping state. The flow limiting plate (121) is used to block the outflow port (113) and restrict the flow of premixed liquid. During the liquid separation stage, the flow limiting plate (121) and the outflow port (113) are in a misaligned state.

5. The urea production apparatus according to claim 4, characterized in that: A horizontal plate (123) is fixedly connected between the two flow restricting plates (121). The output shaft of the motor (124) is fixedly connected in the middle of the horizontal plate (123). The motor (124) is located at the bottom of the mixing tank (100).

6. The urea production apparatus according to claim 4, characterized in that: The turbulence mechanism includes a floating plate (130) floating on the surface of the premixed liquid and a diversion plate (131) rotatably connected to the bottom of the floating plate (130). The floating plate (130) uses the waves formed on the surface of the premixed liquid as power to drive the diversion plate (131) to move up and down in the premixed liquid to turbulent the premixed liquid at different depths.

7. The urea production apparatus according to claim 6, characterized in that: The guide plate (131) is slidably connected to a guide rail (132) fixed to the inner wall of the inner cylinder (110) on one side, and extends towards the axis on the other side, with the end inclined outward to form an outward end. The outward end is used to guide the solution at the wall of the inner cylinder (110) to the inward side, so that the solution at the outer ring of the vortex is mixed with the solution in the middle of the vortex.

8. The urea production apparatus according to claim 6, characterized in that: The flow limiting mechanism (120) also includes a lever (122) fixedly installed inside the flow limiting plate (121). The floating plate (130) is located on the rotation path of the lever (122). The lever (122) is used to rotate the floating plate (130) and block the floating plate (130), so that one end of the floating plate (130) is raised from the surface of the premixed liquid and the other end is submerged in the premixed liquid. A circulation pump (114) is installed inside the outer mixing chamber (112). The pumping pipe of the circulation pump (114) extends into the bottom of the outer mixing chamber (112), and the delivery pipe is connected to the inner mixing chamber (111).

9. The urea production apparatus according to claim 6, characterized in that: A first stop (133) and a second stop (134) are respectively provided on both sides of the rotatable connection between the floating plate (130) and the diversion plate (131). The first stop (133) and the second stop (134) are both fixed to the floating plate (130), and the first stop (133) is close to the rotatable connection, while the second stop (134) is far away from the rotatable connection.

10. The urea production apparatus according to claim 9, characterized in that: The second stop (134) is longer than the first stop (133). The second stop (134) is used to abut against the water-facing surface of the diversion plate (131) to limit the excessive rotation of the floating plate (130). The first stop (133) is used to abut against the water-reverse surface of the diversion plate (131) to limit the reverse rotation of the floating plate (130).

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