An automated dry ice production device

Abstract

This invention discloses an automated dry ice production device, relating to the field of dry ice production. It includes a liquid carbon dioxide input pipeline, which, after passing through a precooler, connects to a buffer tank. The buffer tank is connected to the input port of a pulverizer via a liquid carbon dioxide output pipeline. The output port of the pulverizer is connected to the input port of a granulator. The output port of the granulator is connected to the input port of a briquetting machine. The output port of the briquetting machine is connected to the upstream section of a conveyor line, and the downstream section of the conveyor line is connected to a packaging machine. This invention can significantly improve the efficiency of dry ice production, and it features a high degree of automation and a small footprint.

Description

Technical Field

[0001] This invention relates to the field of dry ice production, and more specifically, to an automated dry ice production apparatus. Background Technology

[0002] Traditional dry ice production involves injecting liquid carbon dioxide into a cylinder, tentatively called a crystallization cylinder. A phase change occurs within the crystallization cylinder: liquid is injected, gas is released, and the solid is collected.

[0003] Aside from dry ice used for cleaning, granulation produces the final product that is sold directly. For dry ice used in the cold chain, which accounts for over 90% of the market share, granulation is only the first step. Its main purpose is to address the issues of poor flowability, large specific surface area, and easy vaporization of dry ice powder. Granulation facilitates subsequent transfer and briquetting.

[0004] Traditional dry ice production typically begins by connecting liquid carbon dioxide from a storage tank (pressure approximately 20-22 bar) to a granulator. The crystallization cylinder operates at approximately -50°C under normal pressure, achieving a phase transition. Under these conditions, the ideal yield is around 50%. However, in reality, during the liquid carbon dioxide injection process into the crystallization cylinder, the decompression is too rapid, causing a significant portion of the solid carbon dioxide (dry ice powder) to vaporize due to intense impact, collision, and friction, resulting in a low overall solid yield during the phase transition. After the valve is closed and liquid injection stops, the hydraulic cylinder pushes the crystallization cylinder to granulate the dry ice once the pressure reaches normal. Finally, dry ice particles are extruded from the mold outlet side of the crystallization cylinder. Currently, most commercially available dry ice granulators achieve a dry ice yield of no more than 42%.

[0005] The low dry ice recovery rate is due to several reasons:

[0006] During the granulation process, a hydraulic cylinder at 25 MPa pressure extrudes the powder from the other side of the mold to form dry ice particles. The temperature rise caused by this extrusion process also causes some of the dry ice to vaporize, reducing the solid yield.

[0007] Specifically, the production process of a traditional dry ice pellet machine can be roughly divided into two parts:

[0008] In the first step, the hydraulic cylinder retracts to the initial position, and LCO2 is injected into the crystallizing cylinder through the LCO2 pipeline valve. When the cycle time is up, the valve is closed to stop the injection. At the same time as the injection, the exhaust gas is discharged. After the pressure relay installed in the crystallizing cylinder receives the atmospheric pressure signal, the second step is carried out.

[0009] The second step involves the hydraulic cylinder rapidly advancing to its mid-front limit near three-quarters of its full stroke; then, it feeds to its far-end limit, stops hydraulic feeding, holds pressure for several seconds, releases pressure, and returns to zero. This process is repeated. A complete cycle typically takes 25-40 seconds.

[0010] Therefore, it is easy to see that traditional dry ice pellet mills, which use hydraulic reciprocating extrusion for pelletizing, have many shortcomings and deficiencies, mainly reflected in:

[0011] 1. During the injection process, due to the large pressure difference, the LCO2 at 20 bar pressure is injected into the atmospheric pressure crystallization cylinder after the valve is opened, resulting in a violent impact. A large number of powder particles collide and rub against each other, causing a large amount of solid to vaporize and sublimate, resulting in a low yield of solid powder dry ice.

[0012] 2. Dry ice particle production is discontinuous and has a long production cycle. From the start of liquid injection, the hydraulic device waits without working. After injection, it still needs to wait for the crystallization cylinder pressure to be fully released before the hydraulic device can advance. This process is essential; otherwise, there is a risk of cylinder explosion. The cycle time for depressurization and venting depends on the screen area and pore size. With a small pore size per unit area screen, less dry ice powder passes through, but the venting cycle is long; with a large pore size, although the venting cycle is short, more dry ice powder passes through, resulting in greater losses and a higher risk of clogging the exhaust pipe. After reaching atmospheric pressure in the crystallization cylinder, the first half of the hydraulic propulsion only accumulates loose powder, and only the last quarter of the stroke produces dry ice particles. The actual production cycle accounts for at most one-sixth of the overall cycle time, resulting in low overall efficiency.

[0013] In addition, the uneven distribution of powder density inside the crystallization cylinder results in a lower density of dry ice particles extruded from the upper part of the mold compared to those extruded from the lower part, leading to poor product density consistency and low quality.

[0014] 3. During the reciprocating motion of the hydraulic device, the return stroke draws in gas from the mold and exhaust pipe to maintain pressure balance on both sides of the extrusion piston. The drawn-in gas, especially water vapor from humid air, will quickly condense and adhere to the various mechanical sliding surfaces after entering the crystallization cylinder, causing premature wear of sealing components, reducing their lifespan, and shortening the maintenance cycle.

[0015] 4. Periodic valve opening and liquid injection result in intermittent exhaust gas emissions, leading to unstable and discontinuous exhaust gas pipeline pressure, which is detrimental to exhaust gas recovery and collection. Even without exhaust gas recovery, the temperature difference between the inside and outside of the exhaust gas pipeline after it returns from high pressure to normal pressure will cause the pipeline pressure to continue to drop. In addition, the negative pressure generated by the return stroke of the hydraulic cylinder will cause the exhaust gas pipeline to draw in more humid air, resulting in ice buildup in the pipeline. Especially after ice buildup on the screen of the crystallization cylinder, the pressure reduction and exhaust performance will be further reduced, the production cycle time will be extended, and the production efficiency will decrease.

[0016] 5. Due to the continuous release of LCO2, the pressure inside the storage tank cannot be balanced by its own evaporation in a short period of time. Therefore, when production is continuously reduced from 90% to 25% of the tank capacity, the pressure drop will exceed 30%. This leads to two problems: First, the valve opening cycle is fixed during dry ice production. The LCO2 delivered by its own pressure will decrease in flow rate due to the pressure drop, resulting in a smaller amount of LCO2 injected per unit cycle, leading to a decrease in production efficiency. At the same time, the dry ice particle density decreases, resulting in poor density consistency and a decline in quality.

[0017] In summary, traditional dry ice pellet machines are better classified as general hydraulic equipment than as process equipment based on precise thermodynamic design.

[0018] Traditional dry ice production for cold chain applications involves three core processes: granulation, briquetting, and packaging. The packaging process is relatively fast, with high-speed pillow packaging machines achieving speeds of hundreds of pieces per minute. Therefore, packaging is not the bottleneck in the overall dry ice production process. Aside from the granulation process, the briquetting process is the bottleneck in the overall production chain.

[0019] Traditional briquetting machines require three sets of hydraulic cylinders to complete the entire briquetting process: a main hydraulic cylinder with a pressure of 60-90 tons to compress granular dry ice into blocks; a horizontal push cylinder to feed and eject the dry ice blocks; and a lower top cylinder to push the compressed dry ice blocks out of the mold. When the horizontal push cylinder feeds again, the front baffle of the hopper pushes the dry ice blocks out.

[0020] Drawer-type feeding devices have a complex structure, are prone to deformation and damage, and have low efficiency.

[0021] The lower cylinder ejects the compressed dry ice blocks. When the horizontal push cylinder feeds again, the front baffle of the hopper pushes the dry ice blocks to the discharge ramp and into the sorting line. After that, the lower cylinder returns, freeing up the lower mold's loading space for dry ice particles to fall in. This completes one cycle of the process.

[0022] It is clear from the above process that the entire process is a single-threaded operation, numerous and lengthy. The core pressing process is still "feeding and discharging," resulting in an unreasonable material flow. Furthermore, the feeding process, which is the horizontal pushing cylinder hopper feed, generally requires two passes; otherwise, the amount of material fed into the lower mold cannot be guaranteed, leading to low density of the dry ice blocks at the front, low quality, and poor product stability and consistency.

[0023] In addition, traditional dry ice production facilities occupy a large area.

[0024] Based on a production capacity of 2 tons per hour, the most compact arrangement would be two pellet mills, one briquetting machine, one feeding line, and one packaging machine to form a production line, requiring a total floor area of ​​7 meters x 8 meters. Considering maintenance space, the floor area would be at least 60-80 square meters.

[0025] As is well known, dry ice has a temperature of -78℃. A less compact layout of the equipment in the production process means a longer flow path for the dry ice and a longer exposure time of the low-temperature material to room temperature. This leads to a series of problems, such as excessive condensation causing corrosion of metal parts, aging of electrical components, and a higher risk of short circuits; high carbon dioxide concentrations in the production area due to dry ice sublimation, requiring improved ventilation and equipment investment; and, more obviously, direct weight loss due to sublimation. This is a major reason why traditional dry ice production methods consume 1 ton of liquid carbon dioxide but rarely produce 400 kg of commercial dry ice. Summary of the Invention

[0026] The technical problem to be solved by the present invention is to provide an automated dry ice production device to solve the problems mentioned in the background art.

[0027] To achieve the above objectives, the present invention adopts the following technical solution:

[0028] An automated dry ice production device includes a liquid carbon dioxide input pipeline, which is connected to a buffer tank after passing through a precooler. The buffer tank is connected to the input port of a pulverizer via a liquid carbon dioxide output pipeline. The output port of the pulverizer is connected to the input port of a granulator. The output port of the granulator is connected to the input port of a briquetting machine. The output port of the briquetting machine is connected to the upstream section of a conveyor line. The downstream section of the conveyor line is connected to a packaging machine.

[0029] Preferably, the top of the buffer tank is connected to the precooler via a pipe to provide cooling capacity to the precooler; the top of the pulverizer is connected to the precooler via a pipe to provide cooling capacity to the precooler.

[0030] Preferred:

[0031] A first PID controller is installed at the input valve of the liquid carbon dioxide input pipeline; the first PID controller controls the opening of the input valve so that the liquid level in the buffer tank is maintained within a preset range.

[0032] The top of the buffer tank is connected to a gas output pipe. A second PID controller is installed at the gas outlet valve of the gas output pipe. The second PID controller controls the opening of the gas outlet valve so that the pressure at the top of the buffer tank is maintained within a preset range.

[0033] The top of the buffer tank is also connected to a liquid carbon dioxide replenishment pipe, the diameter of which is smaller than that of the liquid carbon dioxide input pipe. The liquid carbon dioxide replenishment pipe is used to inject liquid carbon dioxide to replenish the pressure inside the buffer tank. A liquid carbon dioxide replenishment valve is installed at the liquid carbon dioxide replenishment pipe, and a third PID controller is installed at the liquid carbon dioxide replenishment valve. The third PID controller is used to control the opening degree of the liquid carbon dioxide replenishment valve so that the pressure at the top of the buffer tank is maintained within a preset range.

[0034] Preferably, the pulverizer includes a top structure, an upper sidewall, and a lower sidewall that are connected in sequence from top to bottom;

[0035] The upper sidewall has a central axis symmetric structure that is larger at the top and smaller at the bottom.

[0036] The lower sidewall is a cylindrical side surface;

[0037] The top structure is equipped with a motor and a vent, the vent being connected to the pulverizer exhaust pipe; the motor is connected to a vertical rotating rod, the rotating rod being located at the central axis of the upper side wall and the lower side wall;

[0038] The rotating rod is connected to a threaded plate for propulsion at the lower side wall;

[0039] An opening is provided at the top of the upper sidewall, and a tangential input pipe for inputting liquid carbon dioxide is connected to the opening. The end of the tangential input pipe is embedded in the upper sidewall and is tangential to the inner wall of the upper sidewall.

[0040] Preferably, the granulator includes a hollow cylindrical ring die, the top opening of which is the input port of the granulator, and a plurality of side wall openings uniformly provided on the side wall of the ring die as dry ice extrusion channels. A cutter is mounted outside the side wall opening and rotates around the central axis of the ring die. The cutter is used to cut the extruded dry ice.

[0041] Preferably, the ring die is provided with an extrusion module for extruding dry ice; the ring die is also surrounded by a limiting device, which includes a ring-shaped limiting base plate connected to the bottom end of the side wall of the ring die, and a columnar limiting wall vertically connected to the edge of the limiting base plate. The cutting tool is disposed between the limiting wall and the side wall of the ring die; an output opening is provided on the limiting base plate, which is the output port of the granulator.

[0042] Preferably, a pushing block is fixed at the bottom end of the cutter, and the pushing block is attached to the limiting base plate, the limiting wall, and the ring die side wall; when the pushing block is pushed by the cutter to move in a circular motion close to the limiting base plate, the pushing block pushes the dry ice falling on the limiting base plate toward the output port of the granulator.

[0043] Preferably, the briquetting machine includes:

[0044] A circular spinning die, as shown, has three sets of die openings evenly arranged along the central axis.

[0045] There are three workstations: a feeding workstation, a pressing workstation, and a discharging workstation; at the same time, the three sets of mold openings are located at the three workstations respectively.

[0046] A drive mechanism is used to drive the rotating disc mold to rotate, and to make each mold orifice group change its position during rotation;

[0047] The feeding station is used to feed dry ice into the mold opening group, the pressing station is used to press the dry ice in the mold opening group into blocks, and the discharging station is used to discharge the pressed dry ice blocks.

[0048] Preferably, the pressing station is provided with a lower pressing die located below the rotary mold and an upper pressing die located above the rotary mold, and the upper pressing die is connected to the lifting mechanism.

[0049] Preferably, the discharge station is a discharge port connected to the conveyor line below the rotary mold, and the discharge station is a discharge pressure plate connected to the lifting mechanism above the rotary mold.

[0050] The advantages of this invention over the prior art are:

[0051] 1. The precooling unit has two heat exchangers that release two streams of low-temperature, pure CO2 tail gas from the buffer and pulverizer, which are then sequentially passed through a secondary precooler for cold energy recovery. The captured cold energy is used for precooling the feed liquid. This process can reduce the feed liquid temperature and pressure by more than 20%, and increase the overall yield of dry ice solid powder by more than 5%. It also improves the buffer control efficiency.

[0052] 2. LCO2, pre-cooled to below 18 bar and at approximately -30°C, enters the buffer. A gas path leads from the top of the buffer to the precooler, where precise PID control further transforms the CO2 into a critical state (a mixture of solid, liquid, and gaseous states). The internal temperature, pressure, and liquid level of the buffer are automatically controlled by a precise algorithm. Simultaneously, the pressure, temperature, and flow rate are kept constant when the material enters the pulverizer, further stabilizing the consistency of dry ice granule quality. The flow rate entering the pulverizer is based on a precisely designed powder rheological model, ensuring minimal impact and maximum cyclone separation efficiency. This mechanism and process significantly improve the solid yield compared to traditional dry ice granulators.

[0053] 3. After entering the pulverizer, the material will swirl along the inner wall of the pulverizer, evaporating gas during the process, releasing heat and cooling down to become powder. The powder eventually enters the powder collection area of ​​the auger blades (threaded blades) used for propulsion. Servo-driven auger rotation enables precise control of the powder density at the pulverizer outlet and the feed rate for subsequent processes. Gas enters the upper section of the pulverizer upwards in the central region of the flow field, and precise control of the internal operating conditions of the pulverizer can be achieved by controlling the exhaust gas. The exhaust gas can enter the precooler through pipelines for cold energy recovery. Compared with the traditional method of directly injecting LCO2 into the crystallization cylinder in dry ice pellet mills, this invention minimizes the vaporization loss due to collisions between the powder itself and the container during decompression, significantly improving the dry ice solid yield.

[0054] 4. The feed inlet at the top of the granulator and the discharge outlet at the bottom of the pulverizer are connected by a flange. Inside the ring die, the material is squeezed against the inner wall of the ring die by two to three pairs of pressure rollers, causing the powder to be extruded into strips from the die's orifices. The size of the ring die orifice determines the diameter of the dry ice pellets. A servo-driven cage-shaped cutter (blade) rotates coaxially outside the ring die, cutting the strips of dry ice and pushing them to the output port. The length of the dry ice pellets can be controlled by adjusting the rotation speed of the cage-shaped cutter. Traditional dry ice pellet mills use hydraulic reciprocating discharge, which cannot achieve continuous discharge, and suffers from frequent stops and low efficiency. This invention's ring die granulator can achieve continuous top feeding and continuous side discharge. Traditional dry ice pellet mills have approximately 1000-1300 die holes per head for 3mm pellets, and no more than 3000 die holes per double head. The ring die pellet mill can have approximately 12000 die holes and can continuously and rapidly discharge pellets, significantly improving production efficiency and increasing unit capacity by more than three times.

[0055] 5. The dry ice granules are lifted and transferred to the briquetting machine's hopper via a granule conveyor from the granulator outlet. The briquetting process begins once the hopper is ready. The overall architecture of this invention's briquetting machine adopts a mature and stable "four-beam, four-column" basic structure. The main power for briquetting comes from a 150-ton high-speed hydraulic cylinder with both fast and slow speeds. An innovative three-station rotating mechanism allows for simultaneous feeding, briquetting, and discharging in parallel. The rotating die is driven by a servo to rotate between the middle and lower fixed beams; each 120° rotation constitutes a complete briquetting process. Specifically: when the briquetting machine's hopper is ready, the rotating die rotates 120°, filling the previously feeding station with dry ice granules for the first time, and then enters the pressing station; the corresponding part of the lower fixed beam plate at this pressing station is a flat, closed support structure with a "bottom." The pressing cylinder advances downwards to its working position, pressing the dry ice particles inside the mold into nine dry ice blocks. The rotating mold rotates 120° again, and the pressing station continues to hydraulically press the dry ice particles downwards into blocks. The corresponding part of the lower fixed beam plate at the discharge station has a hollow structure and no "bottom." As the moving beam plate advances downwards with the cylinder, the discharge pressure plate fixed below the moving beam plate pushes the nine dry ice blocks from the mold downwards onto the material handling conveyor belt for discharge. The rotating mold rotates 120° again, and the empty mold hopper re-enters the hopper below the briquetting machine for particle filling, thus repeating the cycle. By analyzing and comparing the complex single-pass process of feeding, pressing, ejecting, and pushing in traditional dry ice briquetting machines, the advantages of this invention are very obvious. The "top feeding, bottom discharging" material flow is more rational; the parallel feeding, pressing, and discharging processes significantly shorten the production cycle and greatly improve production efficiency. The rotation of the swivel mold to 120° takes about 1.5 seconds, and the pressing and retraction of the hydraulic cylinder takes about 3 seconds. The total cycle time does not exceed 5 seconds, which can produce 9 pieces of 500g dry ice, producing 6480 pieces of dry ice per hour, or about 3240kg.

[0056] 6. The lower part of the briquetting machine integrates a two-stage material handling and conveying line, which can promptly and orderly transfer the produced blocky dry ice to the packaging machine, resulting in a high degree of automation and high efficiency. Attached Figure Description

[0057] Figure 1 This is a perspective view of the production apparatus of the present invention;

[0058] Figure 2 This is a perspective view of the powderer of the present invention;

[0059] Figure 3 This is a perspective view of the powderer of the present invention;

[0060] Figure 4 This is a perspective view of the granulator of the present invention;

[0061] Figure 5 This is a perspective view of the briquetting machine of the present invention;

[0062] Figure 6 This is a schematic diagram of the spool mold in the briquetting machine of the present invention;

[0063] Figure 7 This is a perspective view of the production apparatus of the present invention.

[0064] In the diagram, 1 is the primary precooler, 2 is the secondary precooler, 3 is the buffer tank, 4 is the pulverizer, 5 is the granulator, and 6 is the briquetting machine.

[0065] 41. Tangential input pipe; 42. Lower side wall; 43. Transition side wall; 44. Upper side wall; 45. Rotating rod; 46. Threaded plate.

[0066] 51. Ring die; 52. Cutting tool; 53. Limiting device; 54. Pushing block; 55. Guide bucket;

[0067] 61. Pressing station; 62. Upper fixed beam plate; 63. Moving beam plate; 64. Base. Detailed Implementation

[0068] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0069] like Figures 1 to 7 The overall device of the present invention will be described as follows:

[0070] The present invention includes a liquid carbon dioxide input pipe, which is connected to a buffer tank 3 after passing through a precooler. The buffer tank 3 is connected to the input port of a pulverizer 4 through a liquid carbon dioxide output pipe. The output port of the pulverizer 4 is connected to the input port of a granulator 5. The output port of the granulator 5 is connected to the input port of a briquetting machine 6. The output port of the briquetting machine 6 is connected to the upstream section of a conveyor line. The downstream section of the conveyor line is connected to a packaging machine.

[0071] The top of buffer tank 3 is connected to the precooler via a pipe to provide cooling capacity to the precooler.

[0072] The top of the pulverizer 4 is connected to the precooler via a pipe to provide cooling capacity to the precooler.

[0073] The precooler is divided into a primary precooler 1 and a secondary precooler 2; the top of the buffer tank 3 is connected to the primary precooler 1 through a pipe, and the top of the pulverizer 4 is connected to the secondary precooler 2 through a pipe.

[0074] The precooler is a heat exchanger, and the cooling capacity of the heat exchanger comes from the gaseous carbon dioxide generated in the buffer tank 3 and the pulverizer 4.

[0075] A first PID controller is installed at the inlet valve of the liquid carbon dioxide inlet pipeline; the first PID controller controls the opening of the inlet valve so that the liquid level in the buffer tank 3 is maintained within a preset range.

[0076] A liquid level sensor is installed inside the buffer tank 3, and the first PID controller is connected to the liquid level sensor.

[0077] The top of buffer tank 3 is connected to a gas output pipe. A second PID controller is installed at the outlet valve of the gas output pipe. The second PID controller controls the opening of the outlet valve to maintain the pressure at the top of buffer tank 3 within a preset range. The preset range can be set between 5-15 bar. The main function of the gas output pipe and the second PID controller is to control the pressure reduction process.

[0078] A buffer tank pressure sensor is installed at the top of the buffer tank 3; a second PID controller is connected to the buffer tank pressure sensor.

[0079] The gas output pipe is connected to the precooler to provide cooling capacity.

[0080] The top of the buffer tank 3 is also connected to a liquid carbon dioxide replenishment pipe. The diameter of the liquid carbon dioxide replenishment pipe is smaller than that of the liquid carbon dioxide input pipe. The liquid carbon dioxide replenishment pipe is used to inject liquid carbon dioxide to replenish the pressure inside the buffer tank 3. A liquid carbon dioxide replenishment valve is installed at the liquid carbon dioxide replenishment pipe, and a third PID controller is installed at the liquid carbon dioxide replenishment valve. The third PID controller is used to control the opening degree of the liquid carbon dioxide replenishment valve so that the pressure at the top of the buffer tank 3 is maintained within a preset range.

[0081] The third PID controller is connected to the buffer tank pressure sensor to receive the pressure information of the buffer tank.

[0082] The liquid carbon dioxide input pipeline and the liquid carbon dioxide replenishment pipeline can be connected to one liquid carbon dioxide storage tank, or respectively to two liquid carbon dioxide storage tanks. The liquid carbon dioxide input pipeline, the liquid carbon dioxide replenishment pipeline, and their corresponding PID controllers serve the functions of coarse-adjustment pressurization and fine-adjustment pressurization, respectively.

[0083] The reason for setting up a third PID controller is to fine-tune the pressure inside the buffer tank, so that the buffer tank always maintains a pressure value close to the preset value during continuous operation. In contrast, the liquid carbon dioxide input pipe plays a coarse adjustment role. Its pipe diameter is larger, which can replenish a large amount of liquid carbon dioxide in a short time, but it is not easy to control the adjustment precision, especially when the buffer tank 3 outputs liquid carbon dioxide and loses pressure. It is difficult to accurately control the input amount at the liquid carbon dioxide input pipe. Therefore, providing a liquid carbon dioxide input pipe with a small diameter and appropriately controlling the injection rate can more accurately and quickly replenish the pressure rapidly lost by the buffer tank 3 when outputting liquid carbon dioxide.

[0084] The pulverizer 4 is equipped with a pulverizer pressure sensor, and the third PID controller is connected to the pulverizer pressure sensor.

[0085] The powderer 4 includes a top structure, an upper side wall 44 and a lower side wall 42 connected in sequence from top to bottom;

[0086] The upper sidewall 44 has a central axis symmetric structure that is larger at the top and smaller at the bottom;

[0087] The lower sidewall 42 is a cylindrical side surface;

[0088] The top structure is equipped with a motor and a vent, which is connected to the pulverizer exhaust pipe; the motor is connected to a vertical rotating rod 45, which is located at the central axis of the upper side wall 44 and the lower side wall 42.

[0089] The rotating rod 45 is connected to a threaded plate 46 for propulsion at the lower side wall 42;

[0090] An opening is provided at the top of the upper sidewall 44, and a tangential input pipe 41 for inputting liquid carbon dioxide is connected to the opening. The end of the tangential input pipe 41 is embedded in the upper sidewall 44 and is tangential to the inner wall of the upper sidewall 44.

[0091] The upper sidewall 44 and the lower sidewall 42 are connected by a transition sidewall 43, which is a frustum sidewall that is larger at the top and smaller at the bottom.

[0092] The top of the threaded plate 46 extends to the inner side of the top of the transition sidewall 43.

[0093] The tangential input pipe 41 extends downward at an angle.

[0094] The angle between the tangential input pipe 41 and the horizontal plane is between 0° and 20°. This causes the powder, after entering the pulverizer, to rotate along the inner wall with the airflow and swirl downwards at an angle.

[0095] The end of the tangential input pipe 41 is a pen tip-shaped guide structure formed by a bevel.

[0096] The curvature of the upper sidewall 44 gradually increases from top to bottom.

[0097] The pulverizer exhaust pipe is connected to the precooler.

[0098] Stainless steel sintered mesh is installed at the ventilation holes of the top structure.

[0099] The granulator 5 includes a hollow cylindrical ring die 51. The top opening of the ring die 51 is the input port of the granulator 5. Multiple side wall openings that serve as dry ice extrusion channels are evenly provided on the side wall of the ring die 51. A cutter 52 that rotates around the central axis of the ring die 51 is mounted outside the side wall opening. The cutter 52 is used to cut the extruded dry ice.

[0100] The ring die 51 is equipped with an extrusion module for extruding dry ice.

[0101] The extrusion module consists of multiple pairs of pressure rollers that rotate around the central axis of the cylinder wall, and the pressure rollers are connected to a motor.

[0102] The cutting tool 52 is connected to an adjustable speed motor.

[0103] The input port of the granulator 5 is connected to the output port of the pulverizer 4 via a flange.

[0104] The ring die 51 is surrounded by a limiting device 53. The limiting device 53 includes a ring-shaped limiting base plate connected to the bottom of the side wall of the ring die 51, and a columnar limiting wall vertically connected to the edge of the limiting base plate. The cutter 52 is disposed between the limiting wall and the side wall of the ring die 51. An output opening is provided on the limiting base plate, which is the output port of the granulator 5.

[0105] A pusher block 54 is fixed at the bottom of the cutter 52. The pusher block 54 is attached to the limiting base plate, the limiting wall and the side wall of the ring mold 51. When the pusher block 54 is pushed by the cutter 52 to move in a circular motion against the limiting base plate, the pusher block 54 pushes the dry ice that has fallen on the limiting base plate toward the output port of the granulator 5.

[0106] A guide hopper 55 is provided below the output port of the granulator 5. The guide hopper 55 includes a guide bottom plate and a guide side wall, with the guide bottom plate inclined downward.

[0107] The briquetting machine 6 includes:

[0108] A circular spinning die, as shown, has three sets of die openings evenly arranged along the central axis.

[0109] There are three workstations: the feeding station, the pressing station 61, and the discharging station; at the same time, the three sets of mold openings are located at the three workstations respectively.

[0110] The drive mechanism is used to drive the rotating disc mold to rotate, and to make each mold orifice group change its position during rotation;

[0111] The feeding station is used to feed dry ice into the mold opening group, the pressing station 61 is used to press the dry ice in the mold opening group into blocks, and the discharge station is used to discharge the pressed dry ice blocks.

[0112] The feeding station is equipped with a support base plate located below the spinning die and a hopper located above the spinning die. The top of the hopper is connected to the output port of the granulator 5.

[0113] The pressing station 61 is equipped with a lower pressing die located below the swivel mold and an upper pressing die located above the swivel mold. The upper pressing die is connected to the lifting mechanism.

[0114] The lifting mechanism includes an upper fixed beam plate 62 fixed to the base 64 and located above the upper pressing die. The fixed end of the hydraulic cylinder is fixed on the upper fixed beam plate 62, and the telescopic end of the hydraulic cylinder is connected to the upper pressing die.

[0115] The upper fixed beam plate 62 is fixed to the base 64 by guide support columns, and the pressing upper mold is fixed to the bottom surface of a moving beam plate 63. The moving beam plate 63 is fixed below the telescopic end of the hydraulic cylinder. A guide opening is provided on the moving beam plate 63, and the guide support column slides through the guide opening.

[0116] The discharge station below the rotary mold is the discharge port connected to the conveyor line, and the discharge station above the rotary mold is the discharge pressure plate connected to the lifting mechanism.

[0117] The lifting mechanism includes an upper fixed beam plate 62 fixed to the base 64 and located above the pressing upper die. The fixed end of the hydraulic cylinder is fixed on the upper fixed beam plate 62, and the telescopic end of the hydraulic cylinder is connected to the discharge pressure plate.

[0118] The upper fixed beam plate 62 is fixed to the base 64 by the guide support column, and the discharge pressure plate is fixed to the bottom surface of a moving beam plate 63. The moving beam plate 63 is fixed below the telescopic end of the hydraulic cylinder. A guide opening is provided on the moving beam plate 63, and the guide support column slides through the guide opening.

[0119] The discharge station below the rotary mold is a discharge port connected to the conveyor line, and the discharge station above the rotary mold is a discharge pressure plate fixed to the bottom surface of the moving beam plate 63.

[0120] The mold opening assembly includes nine rectangular through holes arranged in a 3x3 grid.

[0121] The drive mechanism includes a rotating shaft fixed to the center of the spinning die and a motor connected to the rotating shaft.

[0122] The drive mechanism drives the swivel mold to rotate 120° at fixed intervals.

[0123] The aforementioned feeding station is used to feed dry ice particles into the die nozzle group, the pressing station is used to press the dry ice particles in the die nozzle group into blocks, and the discharging station is used to discharge the pressed dry ice blocks. In the above embodiment, the swivel die adopts a three-die nozzle group form. In other embodiments, a four-die nozzle group form can be adopted, with the included angle between two adjacent die nozzle groups being 90°. In addition, the interior of the die nozzle group does not necessarily have to present nine rectangular through holes arranged in a nine-square grid; it can be determined according to specific circumstances and customer requirements. In the case of four die nozzle groups, each die nozzle group will sequentially undergo the filling, pressing, and discharging processes. Therefore, compared to the case of three die nozzle groups, the production efficiency can be higher at the same rotation speed.

[0124] The process of using this invention is as follows: After being cooled by two-stage precoolers, liquid carbon dioxide enters buffer tank 3. The liquid carbon dioxide in buffer tank 3 will evaporate into gaseous carbon dioxide (the evaporated gaseous carbon dioxide flows back to the first-stage precooler 1 to cool the input liquid carbon dioxide, thereby achieving cold energy recovery). During the evaporation process, liquid carbon dioxide will release heat, thereby further reducing the temperature.

[0125] The cooled liquid carbon dioxide is tangentially injected into the inner wall of the pulverizer 4. As the inner wall of the pulverizer 4 rotates downward in a spiral, gaseous carbon dioxide evaporates (the evaporated gaseous carbon dioxide flows back to the secondary precooler 2 to cool the input liquid carbon dioxide, thereby achieving cold energy recovery), which further reduces the temperature until it is pulverized and enters the threaded plate 46 of the rotating rod 45 of the pulverizer 4. Through the rotation of the rotating rod 45, the threaded plate 46 will push the powder forward to the granulator 5.

[0126] The granulator 5 extrudes the dry ice in strip form from the side wall opening of the ring die 51 through the extrusion module, and cuts it into granules by the cutter 52, which then fall onto the limiting base plate. The pusher block 54 pushes the dry ice on the limiting base plate to fall from the output opening on the limiting base plate to the swivel mold at the feeding station of the briquetting machine 6. The swivel mold rotates and rotates the dry ice to the pressing station 61 for pressing and shaping. The swivel mold continues to rotate and sends the dry ice to the discharge station, where it is discharged by the pressing of the discharge plate and then conveyed to the packaging machine in the downstream section for packaging.

[0127] The present invention may also include:

[0128] Packaging company:

[0129] This high-speed pillow-type packaging machine, featuring a specially customized ultra-short spacer, can package up to 7200 pieces of dry ice per hour using plastic film. The machine's operational functions are controlled by a Siemens PLC, which acts as a slave unit controlled by the main control system via industrial Ethernet communication.

[0130] Palletizing mechanism:

[0131] During production, the palletizing mechanism connects to the material outlet of the packaging machine. Packaged bagged dry ice enters the palletizer through guide troughs and stands upright. Whenever more dry ice arrives, the conveyor belt moves a short distance to the far end. This ensures the bagged dry ice is stacked compactly and neatly, making it convenient for operators or robotic arms to grab and pack into boxes.

[0132] During non-production periods, the palletizing mechanism can be retracted into the machine, making good use of valuable on-site space while maintaining a neat and aesthetically pleasing appearance.

[0133] Packing robot:

[0134] Optional: Six-axis articulated robot with a dedicated gripping manipulator. It communicates efficiently with the main control system via industrial Ethernet, and with the aid of machine vision, can automatically grab rows of finished dry ice from the palletizer and neatly pack them into boxes. It can also perform functions such as opening and closing boxes, calling AGV carts, and reporting packing progress and status.

[0135] Logistics system:

[0136] Optional equipment includes mature AGV (Automated Guided Vehicle) carts and their supporting systems, supplemented by dedicated dry ice refrigerators to achieve unmanned dry ice production workshops. Customized digital warehousing and logistics systems can be developed to meet individual customer needs.

[0137] Electrical control system:

[0138] The overall electrical architecture is scientific and reasonable, with complete communication, control, and alarm functions, and it can be easily connected to higher-level DCS or ERP digital systems.

[0139] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An automated dry ice production apparatus, characterized by, It includes a liquid carbon dioxide input pipe, which is connected to a buffer tank (3) after passing through a precooler. The buffer tank (3) is connected to the input port of a pulverizer (4) through a liquid carbon dioxide output pipe. The output port of the pulverizer (4) is connected to the input port of a granulator (5). The output port of the granulator (5) is connected to the input port of a briquetting machine (6). The output port of the briquetting machine (6) is connected to the upstream section of the conveyor line. The downstream section of the conveyor line is connected to a packaging machine. The powderer (4) includes a top structure, an upper side wall (44) and a lower side wall (42) connected in sequence from top to bottom; The upper sidewall (44) is a central axis symmetrical structure that is larger at the top and smaller at the bottom; The lower sidewall (42) is a cylindrical sidewall; The top structure is provided with a motor and a vent hole, the vent hole being connected to the pulverizer exhaust pipe; the motor is connected to a vertical rotating rod (45), the rotating rod (45) being located at the central axis of the upper side wall (44) and the lower side wall (42); The rotating rod (45) is connected to a threaded plate (46) for propulsion at the lower side wall (42); An opening is provided at the top of the upper sidewall (44), and a tangential input pipe (41) for inputting liquid carbon dioxide is connected to the opening. The end of the tangential input pipe (41) is embedded in the upper sidewall (44) and is tangential to the inner wall of the upper sidewall (44).

2. The automated dry ice production apparatus of claim 1, wherein, The top of the buffer tank (3) is connected to the precooler via a pipe to provide cooling capacity to the precooler; the top of the pulverizer (4) is connected to the precooler via a pipe to provide cooling capacity to the precooler.

3. The automated dry ice production apparatus according to claim 1, characterized in that: A first PID controller is installed at the input valve of the liquid carbon dioxide input pipeline; the first PID controller controls the opening of the input valve so that the liquid level in the buffer tank (3) is maintained within a preset range; The top of the buffer tank (3) is connected to the gas output pipe. A second PID controller is provided at the gas outlet valve of the gas output pipe. The second PID controller controls the opening of the gas outlet valve so that the pressure at the top of the buffer tank (3) is kept within a preset range. The top of the buffer tank (3) is also connected to a liquid carbon dioxide replenishment pipe, the diameter of which is smaller than that of the liquid carbon dioxide input pipe; the liquid carbon dioxide replenishment pipe is used to spray liquid carbon dioxide to replenish the pressure inside the buffer tank (3); wherein, a liquid carbon dioxide replenishment valve is provided at the liquid carbon dioxide replenishment pipe, and a third PID controller is provided at the liquid carbon dioxide replenishment valve, the third PID controller is used to control the opening degree of the liquid carbon dioxide replenishment valve so that the pressure at the top of the buffer tank (3) is kept within a preset range.

4. The automated dry ice production apparatus of claim 1, wherein, The granulator (5) includes a hollow cylindrical ring die (51). The top opening of the ring die (51) is the input port of the granulator (5). Multiple side wall openings that serve as dry ice extrusion channels are evenly provided on the side wall of the ring die (51). A cutter (52) that rotates around the central axis of the ring die (51) is mounted outside the side wall opening. The cutter (52) is used to cut the extruded dry ice.

5. The automated dry ice production apparatus according to claim 4, characterized in that, The ring die (51) is provided with an extrusion module for extruding dry ice; the ring die (51) is also surrounded by a limiting device (53), the limiting device (53) includes a ring-shaped limiting base plate connected to the bottom of the side wall of the ring die (51), and a columnar limiting wall vertically connected to the edge of the limiting base plate. The cutting tool (52) is disposed between the limiting wall and the side wall of the ring die (51); an output opening is provided on the limiting base plate, the output opening being the output port of the granulator (5).

6. The automated dry ice production apparatus according to claim 5, characterized in that, The bottom end of the cutter (52) is fixed with a push block (54), which is attached to the limiting base plate, the limiting wall and the side wall of the ring mold (51). When the push block (54) is pushed by the cutter (52) to move in a circular motion close to the limiting base plate, the push block (54) pushes the dry ice that has fallen on the limiting base plate toward the output port of the granulator (5).

7. The automated dry ice production apparatus according to claim 1, characterized in that, The briquetting machine (6) includes: A circular spinning die, as shown, has three sets of die openings evenly arranged along the central axis. The three stations are the feeding station, the pressing station (61), and the discharging station; at the same time, the three sets of mold openings are located at the three stations respectively. A drive mechanism is used to drive the rotating disc mold to rotate, and to make each mold orifice group change its position during rotation; The feeding station is used to feed dry ice into the mold opening group, the pressing station (61) is used to press the dry ice in the mold opening group into blocks, and the discharge station is used to discharge the pressed dry ice blocks.

8. The automated dry ice production apparatus according to claim 7, characterized in that, The pressing station (61) is provided with a lower pressing die located below the rotary mold and an upper pressing die located above the rotary mold, and the upper pressing die is connected to the lifting mechanism.

9. The automated dry ice production apparatus according to claim 7, characterized in that, The discharge station below the rotary mold is a discharge port connected to the conveyor line, and the discharge station above the rotary mold is a discharge pressure plate connected to the lifting mechanism.

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