PMI foam raw material mixing and stirring kettle

Abstract

This invention relates to the field of chemical mixing equipment, and in particular to a PMI foam raw material mixing and stirring vessel. Its structure includes: a cylinder body, an upper stirring section, a bottom stirring section, and an independent drive shaft. A switching pressure drive mechanism is located at the bottom center of the cylinder body, which works in conjunction with the bottom stirring section. Because PMI foam raw material easily adheres and solidifies at the bottom of the vessel, has poor fluidity, and is prone to stratification and caking, the switching pressure drive mechanism can control the bottom stirring section to switch between stirring and scraping modes. Combined with a differential transmission structure, the bottom stirring speed is higher than the upper stirring speed. Through the independent drive component and intermittent scraping design, solidified material at the bottom of the vessel can be removed promptly, preventing raw material caking and accumulation, ensuring uniform mixing, and meeting the specific mixing process requirements of PMI foam raw material. By installing a liftable scraper structure and a matching pressure drive component, the solidified raw material adhering to the bottom of the vessel is effectively removed, avoiding the problem of uneven mixing caused by raw material caking.

Description

Technical Field

[0001] This invention is a PMI foam raw material mixing and stirring vessel, belonging to the field of chemical mixing equipment. Background Technology

[0002] The stirred tank is a core material mixing equipment in the fields of chemical engineering and high-performance composite material preparation. It stirs and mixes the materials in the tank through a built-in stirring mechanism. It is widely used in the batching and mixing of special polymer materials such as PMI foam. PMI foam raw materials have unique material characteristics during the stirring preparation process. During the stirring process, the viscosity will continue to increase gradually. The material itself has poor fluidity and is very easy to settle to the bottom of the tank and adhere tightly to the inner wall of the bottom of the tank. After a short time, solidification, caking and clumping will occur. Moreover, the raw materials have strict requirements on the stirring speed and the bottom material disturbance efficiency. Conventional stirring methods are difficult to meet the requirements for uniform mixing.

[0003] Existing conventional mixing tanks all have fixed mixing structures, which cannot achieve the lifting and lowering of the bottom mixing components or the switching of operating conditions. They also cannot achieve differentiated speed control of the upper and lower mixing sections. For PMI foam raw materials, it is impossible to perform timed scraping of the bottom of the tank, which can easily lead to the material adhering, solidifying, and stratifying at the bottom of the tank. This not only affects the uniformity of material mixing, but also cannot meet the special mixing process requirements of this raw material. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a PMI foam raw material mixing and stirring vessel to solve the problems of conventional stirring vessels, which all have fixed stirring structures, cannot achieve the lifting and lowering of the bottom stirring component and the switching of working conditions, nor can they achieve differentiated speed control of the upper and lower stirring parts. Furthermore, PMI foam raw materials cannot be scraped from the bottom of the vessel at regular intervals, which easily leads to the material adhering, solidifying, and stratifying at the bottom of the vessel, affecting the uniformity of material mixing and failing to meet the special stirring process requirements of this raw material.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: A PMI foam raw material mixing and stirring vessel includes a cylinder body, wherein an upper stirring part and a bottom stirring part are coaxially arranged along the central axis of the cylinder body, the upper stirring part and the bottom stirring part are respectively equipped with independent drive shafts, and a drive assembly is provided at the top of the cylinder body corresponding to the upper stirring part and the bottom stirring part; A switching pressure drive mechanism is installed at the center bottom of the cylinder. The switching pressure drive mechanism is in transmission cooperation with the bottom stirring part. Because PMI foam raw material is easy to adhere and solidify at the bottom of the kettle, has poor fluidity and is prone to stratification and caking, the switching pressure drive mechanism can control the bottom stirring part to achieve intermittent switching between two modes: high-level suspension stirring and low-level bottom scraping. It can alternate between regular stirring and timed bottom scraping according to the process sequence to remove solidified material accumulation at the bottom of the kettle in time and avoid caking and stratification of PMI raw material. The bottom stirring part is coaxially arranged below the upper stirring part. The bottom stirring part includes an inner drive shaft and a scraper blade. The outer wall of the inner drive shaft is provided with a transmission groove with a concave and convex structure. The scraper blade is adapted and fitted into the transmission groove. The scraper blade can float up and down along the transmission groove. At the same time, the circumferential rotational torque is transmitted to the inner drive shaft through the concave and convex interlocking structure of the transmission groove. The switching pressure drive mechanism includes a sealing bushing and a switching drive shaft. The switching drive shaft is vertically inserted inside the sealing bushing, and the upper end of the switching drive shaft extends into and is sleeved on the inner side of the scraper blade. The sealing bushing is tightly fitted and fixed to the inner wall of the cylinder. A limiting groove is opened at the bottom of the scraper blade, and the outer side of the sealing bushing is adapted to be installed inside the limiting groove of the scraper blade.

[0006] Preferably, the upper stirring part is vertically assembled along the central axis of the cylinder body. The upper stirring part includes an outer sleeve drive shaft and multiple sets of stirring blades. The multiple sets of stirring blades are circumferentially and uniformly fixed to the outside of the outer sleeve drive shaft. The inner drive shaft is coaxially nested inside the outer sleeve drive shaft. The inner drive shaft and the outer sleeve drive shaft rotate independently. The shape of the scraper blade is adapted to the curvature of the inner wall of the bottom of the cylinder. The scraper blade is integrally formed and has a shovel blade and a cutting blade with an inclined slope. Several discharge holes are opened on the scraper blade plate.

[0007] Preferably, the switching pressure drive mechanism includes a spacer bearing, a support frame, a pressure spring, and a switching cylinder; A spacer bearing is installed between the switching drive shaft and the scraper blade. The spacer bearing isolates the transmission of rotational torque, so that when the scraper blade rotates with the inner drive shaft, the rotational torque will not be transmitted to the switching drive shaft. The switching drive shaft only performs vertical linear displacement and does not rotate with it.

[0008] Preferably, a pressure spring is symmetrically arranged between the bottom of the cylinder and the switching drive shaft, and the pressure spring always applies a constant downward preload force to the switching drive shaft; A switching cylinder is fixedly installed at the bottom of the cylinder body via a support frame, and the telescopic end of the switching cylinder is fastened to the switching transmission shaft.

[0009] Preferably, the drive assembly includes a main motor and a scraper motor. Two sets of transmission gears are fixedly sleeved on the output shaft of the main motor. A transmission gear ring is integrally formed at the top of the outer sleeve transmission shaft. The transmission gear ring meshes with the corresponding transmission gear on the output shaft of the main motor. The gear ratio between the transmission gear on the output shaft of the main motor and the transmission gear ring at the top of the outer sleeve transmission shaft is 1:1.

[0010] Preferably, an axial transmission block is axially movable on the upper part of the inner transmission shaft, and a force-applying spring is installed between the inner transmission shaft and the axial transmission block. The force-applying spring always applies an upward axial preload to the axial transmission block. The axial transmission block is provided with a secondary gear at its top. Another set of transmission gears on the output shaft of the main motor is meshed with the secondary gear in a non-equal gear ratio configuration with a transmission ratio greater than 1:1, so that the rotational speed of the inner transmission shaft is higher than that of the outer sleeve transmission shaft. The top of the axial transmission block and the bottom of the secondary gear are both provided with matching ratchet meshing grooves. Through the meshing of the ratchet meshing grooves, the rotational torque of the main motor is transmitted to the secondary gear and the axial transmission block in sequence, which ultimately drives the inner transmission shaft to rotate synchronously. The axial transmission block can also complete axial displacement with the inner transmission shaft.

[0011] Preferably, the top of the axial transmission block is provided with a transmission slot, and a rotating protruding force transmission rod is axially slidably sleeved on the output shaft of the scraper motor, and a matching limiting and positioning block is provided on the rotating protruding force transmission rod. The scraper motor can drive the rotating protruding force transmission rod to rotate circumferentially. Through the limiting and positioning block, the rotating protruding force transmission rod rotates clockwise and synchronously produces an axial downward protruding action. The lower end structure of the rotating protruding force transmission rod is matched and engaged with the transmission groove on the top of the axial transmission block. The axial floating tolerance margin is formed by the force spring between the inner transmission shaft and the axial transmission block. At the same time, the downward movement of the rotating protruding force transmission rod can disengage the ratchet meshing groove between the secondary gear and the axial transmission block, cut off the original power transmission, and thus form an independent power path.

[0012] The PMI foam raw material mixing and stirring tank of the present invention has the following effects: 1. By installing an independently driven dual-shaft transmission structure and a differential speed proportioning mechanism, the upper and lower mixing structures are driven by different power, achieving differentiated control of uniform operation of the upper mixing section and high-speed operation of the lower mixing section. This adapts to the mixing requirements of PMI foam raw materials, effectively solving the problems of single speed and insufficient material flow at the bottom in traditional mixing equipment. It achieves uniform mixing of materials, avoids material accumulation at the bottom, improves mixing efficiency, and ensures that PMI raw materials do not stratify or solidify during the mixing process.

[0013] 2. By installing a liftable scraper structure and matching pressure drive components, combined with timed control logic, flexible switching between stirring and scraping modes is achieved. The bottom material cleaning operation can be completed according to the preset sequence, effectively removing the solidified raw materials attached to the bottom of the vessel, avoiding the problem of uneven mixing caused by raw material caking. At the same time, with the help of the pre-tightening force of the pressure spring, it is ensured that the scraper is in close contact with the bottom of the vessel, cleaning up the dead corner material.

[0014] 3. By setting up a dual-power path switching structure and corresponding transmission gears, spacer bearings and other components, bidirectional switching between main motor drive and individual scraping drive is realized. No additional drive equipment is needed to complete the switching of different working conditions, simplifying the equipment structure and reducing production costs. At the same time, the ratchet meshing fault-tolerant design can adapt to the raw material mixing requirements at different stages. Attached Figure Description

[0015] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the structure of a PMI foam raw material mixing and stirring vessel according to the present invention; Figure 2 This is a schematic cross-sectional view of the overall structure of the present invention; Figure 3 For the present invention Figure 2 Detailed diagram of point B in the middle; Figure 4 This is an enlarged structural schematic diagram of the switching pressure driving mechanism of the present invention; Figure 5 This is a partial cross-sectional view of the present invention; Figure 6 This is a schematic diagram of the scraper motor and related components of the present invention; Figure 7 For the present invention Figure 2 Enlarged diagram of point A in the middle.

[0016] Explanation of reference numerals in the attached figures: 1. Cylinder block; 2. Upper stirring section; 21. Outer sleeve drive shaft; 211. Drive gear ring; 22. Stirring blades; 3. Bottom stirring section; 31. Inner drive shaft; 311. Drive groove; 32. Scraper blade; 321. Hoeing blade; 322. Cutting blade; 323. Discharge hole; 324. Limiting groove; 33. Axial drive block; 331. Drive groove; 34. Force spring; 35. Secondary gear; 36. Racket engagement groove; 4. Drive assembly; 41. Main motor; 411. Transmission gear; 42. Scraper motor; 43. Rotary protruding force transmission rod; 44. Limiting and positioning block; 5. Switch the pressure drive mechanism; 51. Sealed bushing; 52. Switch the drive shaft; 53. Spacer bearing; 54. Support frame; 55. Pressure spring; 56. Switch the cylinder. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0018] Furthermore, in the description of this invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0019] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral unit; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. However, specifying a direct connection indicates that the two main bodies are not connected through a transitional structure, but rather formed as a whole through a connecting structure. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0020] In this invention, unless otherwise expressly specified and limited, the first feature "on" or "below" the second feature may be in direct contact with the first and second features, or indirect contact through an intermediate medium. In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0021] This invention addresses the shortcomings of existing technologies and the pain points specific to PMI foam raw materials by providing a highly adaptable mixing and stirring vessel for PMI foam raw materials. Through the coordinated operation of a coaxial nested independent dual-shaft structure, differential transmission ratio, liftable floating scraper structure, intermittent switching pressure drive mechanism, and dual power path clutch switching structure, it solves the problems of bottom settling, adhesion solidification, caking and stratification, and uneven mixing during the mixing process of PMI foam raw materials.

[0022] Please see Figures 1 to 7 This invention provides a PMI foam raw material mixing and stirring vessel. The technical solution is as follows: The PMI foam raw material mixing and stirring vessel of this invention includes a vertical sealed cylinder 1. An upper stirring part 2 and a bottom stirring part 3 are coaxially arranged along the central vertical axis inside the cylinder 1. The upper stirring part 2 and the bottom stirring part 3 are respectively equipped with independent drive shafts. A complete drive assembly 4 is fixedly installed at the top of the cylinder 1 corresponding to the two independent drive shafts. A switching pressure driving mechanism 5 that is in transmission cooperation with the bottom stirring part 3 is fixedly installed at the bottom center of the cylinder 1.

[0023] The upper stirring part 2 is vertically fixed along the central axis of the cylinder 1. The upper stirring part 2 includes an outer sleeve drive shaft 21 and multiple sets of circumferentially evenly distributed stirring blades 22. The stirring blades 22 are fixedly installed on the outer side wall of the outer sleeve drive shaft 21 and are used to perform routine full-area stirring, turning and mixing of the PMI foam raw material in the upper middle part of the cylinder 1 to ensure the overall uniformity of the material mixing. The bottom stirring section 3 is coaxially positioned directly below the upper stirring section 2. The bottom stirring section 3 includes an inner drive shaft 31 and a scraper blade 32. The inner drive shaft 31 is coaxially and loosely nested in the internal cavity of the outer sleeve drive shaft 21. The inner drive shaft 31 and the outer sleeve drive shaft 21 are isolated from each other and can achieve independent relative rotational motion. The outer side wall of the inner drive shaft 31 is provided with an axially extending concave-convex structure transmission groove 311. The center mounting end of the scraper blade 32 is fitted and snapped into the transmission groove 311. The scraper blade 32 can make a small axial up-and-down floating displacement along the transmission groove 311. At the same time, through the concave-convex interlocking structure of the transmission groove 311, the circumferential rotational torque of the inner drive shaft 31 is stably transmitted, ensuring that the scraper blade 32 rotates synchronously with the inner drive shaft 31 while having axial floating adaptation capability. The overall outer contour of the scraper blade 32 is perfectly matched and fitted with the inner wall curvature of the bottom of the cylinder 1. The scraper blade 32 is integrally formed with a shovel blade 321 with an inclined slope and a cutting blade 322 for cutting solidified and lumpy materials. Multiple through discharge holes 323 are evenly opened on the plate surface of the scraper blade 32. The discharge holes 323 can not only guide and discharge the solidified material cut and peeled off by the shovel blade 321 in sections to avoid the accumulation of lumpy materials, but also guide and break the flow of materials during high-speed rotation and stirring, thereby accelerating the flow rate and circulation disturbance effect of materials at the bottom of the vessel.

[0024] The switching pressure drive mechanism 5 is integrated and installed at the center bottom of the cylinder body 1. The entire mechanism includes a sealing bushing 51, a switching drive shaft 52, a spacer bearing 53, a fixed support frame 54, symmetrically arranged pressure springs 55, and a switching cylinder 56. The sealing bushing 51 is tightly embedded and fixed at the center of the inner wall of the cylinder body 1 to achieve a tight seal inside the vessel and prevent material leakage. A limiting groove 324 is opened at the bottom center of the scraper blade 32. The external fitting gap of the sealing bushing 51 is fitted inside the limiting groove 324 of the scraper blade 32, which achieves radial positioning and limitation without affecting the normal rotation and axial lifting of the scraper blade 32. The switching drive shaft 52 is vertically coaxially inserted into the center of the sealed bushing 51. The upper end of the switching drive shaft 52 extends upward and is coaxially sleeved on the inner side of the center of the scraper blade 32. A spacer bearing 53 is fixedly assembled between the switching drive shaft 52 and the inner wall of the scraper blade 32. The core function of the spacer bearing 53 is to completely isolate the axial transmission of rotational torque, so that when the scraper blade 32 rotates at high speed with the inner drive shaft 31, the rotational torque will not be transmitted to the switching drive shaft 52 at all. This ensures that the switching drive shaft 52 only performs axial vertical linear displacement and does not rotate with it throughout the entire process. The rotational movement of the scraper blade 32 and the lifting and lowering movement of the switching drive shaft 52 are completely independent of each other.

[0025] The pressure springs 55 are symmetrically arranged and installed between the bottom inner wall of the cylinder body 1 and the bottom end of the switching drive shaft 52. The symmetrically arranged pressure springs 55 always synchronously apply a constant and uniform downward axial preload to the switching drive shaft 52, ensuring uniform and stable downward pressure when scraping the material at the bottom. A switching cylinder 56 is fastened to the outer side of the bottom of the cylinder body 1 by a fixed support frame 54. The vertical extension end of the switching cylinder 56 is coaxially connected to the bottom end of the switching drive shaft 52. Through the extension and retraction of the switching cylinder 56, combined with the preload of the pressure springs 55, the stable switching between the two working conditions of the bottom stirring section 3 is achieved: when the equipment is in the normal stirring condition, the switching cylinder 56 pushes the switching drive shaft 52 upward, overcoming the preload of the pressure springs 55 and driving the scraper blade 32 to move upward as a whole, detaching from the bottom inner wall of the cylinder body 1. The equipment is in a high-level suspended state and performs high-speed bottom stirring. When the equipment needs to perform bottom scraping operation, the switching cylinder 56 retracts to relieve pressure, and the constant preload of the pressure spring 55 acts downward on the switching drive shaft 52, and transmits the uniform downward pressure to the scraper blade 32 in a synchronous manner, so that the scraper blade 32 always fits tightly and stably against the inner wall of the bottom of the cylinder 1, realizing constant pressure bottom scraping. According to the solidification law of PMI raw materials, the equipment can alternate between conventional stirring and timed bottom scraping according to the preset process sequence, and promptly remove the solidified material attached to the bottom of the vessel.

[0026] The drive assembly 4 includes two independent power units: a main motor 41 and a scraper motor 42. Two sets of coaxially arranged transmission gears 411 are fixedly mounted on the output shaft of the main motor 41. A transmission gear ring 211 is integrally formed at the top of the outer sleeve transmission shaft 21. This transmission gear ring 211 meshes with a corresponding set of transmission gears 411 on the output shaft of the main motor 41, and the gear ratio of this meshing transmission pair is strictly set to 1:1, achieving synchronous transmission at the same speed between the outer sleeve transmission shaft 21 and the main motor 41, ensuring stable and controllable rotational speed of the upper stirring section 2. The other set of transmission gears 411 on the output shaft of the main motor 41 meshes with the transmission component at the top of the inner transmission shaft 31 using a non-equal gear ratio. The transmission ratio of this pair is greater than 1:1, ensuring that the stable rotational speed of the inner transmission shaft 31 is always higher than the rotational speed of the outer sleeve transmission shaft 21. This eliminates the need for an additional independent motor, enabling high-speed rotation of the bottom stirring section 3.

[0027] An axial transmission block 33 is slidably mounted on the upper part of the inner transmission shaft 31. A force-applying spring 34 is fixedly mounted between the shaft end of the inner transmission shaft 31 and the axial transmission block 33. The force-applying spring 34 always applies a stable upward axial preload to the axial transmission block 33 to ensure the stability of the transmission engagement and the axial floating fault tolerance. A secondary gear 35 is integrally formed at the top of the axial transmission block 33. The secondary gear 35 and the corresponding transmission gear 411 of the main motor 41 are both provided with matching ratchet meshing grooves 36. Through the meshing of the ratchet meshing grooves 36, the rotational torque of the main motor 41 is stably transmitted sequentially to the secondary gear 35 and the axial transmission block 33, ultimately driving the inner transmission shaft 31 to rotate synchronously. At the same time, the axial transmission block 33 can synchronously complete the axial lifting displacement with the inner transmission shaft 31.

[0028] The top end face of the axial transmission block 33 is provided with a matching transmission groove 331. The output shaft of the scraper motor 42 is axially slidably fitted with a rotating protruding force transmission rod 43. The rotating protruding force transmission rod 43 is provided with a matching limiting positioning block 44. Through the limiting and guiding cooperation of the limiting positioning block 44, when the scraper motor 42 drives the rotating protruding force transmission rod 43 to rotate clockwise, it can drive the rotating protruding force transmission rod 43 to synchronously generate an axial downward protruding action. Reverse rotation can drive the rotating protruding force transmission rod 43 to move upward and retract. The lower end head structure of the rotating protruding force transmission rod 43 is concave and convex with the transmission groove 331 on the top of the axial transmission block 33 and can be engaged and connected. At the same time, the force spring 34 between the inner transmission shaft 31 and the axial transmission block 33 provides axial floating tolerance margin to ensure that the concave and convex meshing structure is aligned and stably engaged, and there will be no problem of jamming or sticking. When the rotating protruding force transmission rod 43 moves downward and engages with the transmission slot 331, it can simultaneously push the axial transmission block 33 downward, causing the ratchet meshing groove 36 between the secondary gear 35 and the transmission gear 411 of the main motor 41 to completely disengage, thus completely cutting off the original power transmission path of the main motor 41 to the inner transmission shaft 31, thereby forming a completely independent dedicated power path for scraping: the scraping motor 42 provides independent power, which is sequentially transmitted through the rotating protruding force transmission rod 43, the axial transmission block 33, and the inner transmission shaft 31, and finally stably transmitted to the scraper blade 32. This realizes that the scraping motor 42 provides independent power drive and independent working condition control for the bottom stirring part 3. The speed and running sequence can be adjusted independently during the scraping operation, and the control is completely separated from the conventional stirring of the upper stirring part 2.

[0029] When in use, the system defaults to the normal mixing and stirring mode: the switching cylinder 56 extends upward, pushing the switching drive shaft 52 upward, causing the scraper blade 32 to be in a high-level suspended state, maintaining a gap with the bottom of the cylinder 1; at this time, the main motor 41 synchronously drives the two sets of transmission gears 411 to operate, and the outer sleeve transmission shaft 21 operates at a constant speed under a 1:1 gear ratio, driving the upper stirring blade 22 to perform full-area stirring of the material in the cylinder 1; at the same time, the secondary gear 35 and the transmission gear 411 of the main motor 41 are meshed and driven through the ratchet meshing groove 36, and the inner drive shaft 31 rotates at a high speed higher than the upper stirring part 2 under a transmission ratio greater than 1:1, driving the scraper blade 32 to rotate at high speed, strongly disturbing the PMI raw material settling at the bottom of the vessel, and accelerating the flow of the bottom material.

[0030] When the equipment has been running for a preset time and the time point when PMI raw materials are prone to adhesion and solidification has been reached, the system automatically switches to the bottom scraping mode: First, the scraping motor 42 starts and rotates clockwise, driving the rotating protruding force transmission rod 43 to rotate downward. The head of the rod engages with the transmission slot 331 at the top of the axial transmission block 33, while simultaneously pushing the axial transmission block 33 to compress the force spring 34 downward, so that the secondary gear 35 completely disengages from the ratchet meshing groove 36 of the transmission gear 411 of the main motor 41, cutting off the power transmission from the main motor 41 to the internal transmission shaft 31; then, the switching cylinder 56 retracts to relieve the force, and the symmetrically arranged pressure springs 55 synchronously apply a constant preload downward. The force pushes the switching drive shaft 52 and the scraper blade 32 downward as a whole, so that the scraper blade 32 is completely in contact with the inner wall of the bottom of the cylinder 1. At this time, the scraper motor 42 drives the extended force transmission rod 43, the axial transmission block 33, the inner transmission shaft 31, and the scraper blade 32 to rotate synchronously. The shovel blade 321 on the scraper blade 32 scrapes and peels off the solidified material attached to the bottom of the vessel, and the cutting blade 322 cuts the lumpy material into sections. The material is discharged through the discharge hole 323 and re-enters the material circulation system. Throughout the process, the scraper blade 32 is always in contact with the bottom of the vessel under the constant pressure of the pressure spring 55, with no dead corners for scraping, and the solidified material is completely removed.

[0031] After the scraping operation is completed, the scraping motor 42 rotates in the reverse direction, thereby driving the rotating protruding force transmission rod 43 to move upward and retract. It should be clearly stated that the downward stroke of the rotating protruding force transmission rod 43 is strictly limited. It is only used to push the axial transmission block 33 downward, so as to disengage the secondary gear 35 from the transmission gear 411 of the main motor 41 to cut off the power transmission. It cannot extend downward indefinitely to avoid excessive downward movement that may cause interference or damage to components. When the scraping motor 42 reverses and the rotating protruding force transmission rod 43 moves upward and completely disengages from the transmission slot 331 at the top of the axial transmission block 33, the axial transmission block 33 moves upward under the elastic reset action of the force spring 34. Since the secondary gear 35 and the transmission gear of the main motor 41... The gears 411 are engaged by a ratchet groove 36. The ratchet groove 36 has a certain axial tolerance space, which can accommodate the small displacement deviation during the reset process of the axial transmission block 33. This ensures that after the axial transmission block 33 is reset, the ratchet groove 36 of the secondary gear 35 and the transmission gear 411 of the main motor 41 can stably mesh and restore the meshing state, thereby re-realizing the power transmission of the main motor 41 to the inner transmission shaft 31. At the same time, the switching cylinder 56 pushes the switching transmission shaft 52 upward to reset, driving the scraper blade 32 to move upward as a whole, detaching from the bottom inner wall of the cylinder 1, and returning to the high-level suspension stirring condition. Subsequently, the above conventional stirring and bottom scraping actions are repeated according to the preset process sequence.

[0032] Power Switching Instructions: The power switching of this PMI foam raw material mixing and stirring vessel mainly enables bidirectional switching between the main motor 41 and the scraper motor 42. Under normal stirring conditions, the main motor 41 drives the outer sleeve drive shaft 21 of the upper stirring section 2 and the inner drive shaft 31 of the bottom stirring section 3 through two sets of transmission gears 411. The transmission gears 411 of the main motor 41 and the top transmission gear ring 211 of the outer sleeve drive shaft 21 are connected... The 1:1 constant speed meshing engages with the non-uniform gear ratio of the secondary gear 35 at the top of the axial transmission block 33. Through the engagement of the ratchet meshing groove 36, torque is transmitted to the inner transmission shaft 31, enabling the upper and lower stirring parts to operate at different speeds. When switching to scraping mode, the scraping motor 42 rotates clockwise, driving the rotating outward force transmission rod 43, which has a limit structure, downward. Its lower end engages with the transmission slot 331 at the top of the axial transmission block 33, pushing the axial transmission block 33 downward. This disengages the secondary gear 35 from the ratchet meshing groove 36 of the transmission gear 411 of the main motor 41, cutting off the main motor 41. Regarding the power transmission of the inner drive shaft 31, the scraper motor 42 transmits torque to the inner drive shaft 31 through the rotating protruding force transmission rod 43 and the axial transmission block 33, enabling the scraper blade 32 to rotate independently for scraping. After scraping is completed, the scraper motor 42 rotates in the opposite direction, driving the rotating protruding force transmission rod 43 to move upward and retract. The axial transmission block 33 is reset under the action of the force spring 34. Relying on the axial fault tolerance space of the ratchet meshing groove 36, the secondary gear 35 re-meshes with the transmission gear 411 of the main motor 41, restoring the drive of the main motor 41, completing the power switch and returning to the normal stirring condition.

[0033] The above description only outlines the basic principles and preferred embodiments of the present invention. Those skilled in the art can make many changes and modifications based on the above description, and these changes and modifications should fall within the protection scope of the present invention.

[0034] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A PMI foam raw material mixing and stirring vessel, comprising a cylinder (1), characterized in that: The cylinder (1) has an upper stirring part (2) and a bottom stirring part (3) arranged coaxially along the central axis. The upper stirring part (2) and the bottom stirring part (3) are each equipped with an independent drive shaft. The top of the cylinder (1) is equipped with a drive assembly (4) corresponding to the upper stirring part (2) and the bottom stirring part (3). The cylinder (1) is equipped with a switching pressure driving mechanism (5) at the bottom center. The switching pressure driving mechanism (5) is in transmission cooperation with the bottom stirring part (3). Because PMI foam raw material is easy to adhere and solidify at the bottom of the kettle, has poor fluidity and is easy to layer and clump, the switching pressure driving mechanism (5) can control the bottom stirring part (3) to realize the two modes of high-level suspension stirring and low-level bottom scraping intermittently switching operation. The bottom stirring part (3) is coaxially arranged below the upper stirring part (2). The bottom stirring part (3) includes an inner drive shaft (31) and a scraper blade (32). The outer wall of the inner drive shaft (31) is provided with a transmission groove (311) with a concave and convex structure. The scraper blade (32) is adapted and fitted in the transmission groove (311). The scraper blade (32) can float up and down along the transmission groove (311). At the same time, the circumferential rotational torque is transmitted to the inner drive shaft (31) through the concave and convex interlocking structure of the transmission groove (311). The switching pressure driving mechanism (5) includes a sealing bushing (51) and a switching transmission shaft (52). The sealing bushing (51) is fastened and fixed to the inner wall of the cylinder (1). A limiting groove (324) is opened at the bottom of the scraper blade (32). The outer side of the sealing bushing (51) is adapted to be installed inside the limiting groove (324) of the scraper blade (32). The switching transmission shaft (52) is vertically inserted into the sealing bushing (51), and the upper end of the switching transmission shaft (52) extends into and is sleeved on the inner side of the scraper blade (32).

2. The PMI foam raw material mixing and stirring tank according to claim 1, characterized in that: The upper stirring part (2) is vertically assembled along the central axis of the cylinder body (1). The upper stirring part (2) includes an outer sleeve drive shaft (21) and multiple sets of stirring blades (22). The multiple sets of stirring blades (22) are circumferentially and uniformly fixed on the outside of the outer sleeve drive shaft (21). The inner drive shaft (31) is coaxially nested inside the outer sleeve drive shaft (21). The inner drive shaft (31) and the outer sleeve drive shaft (21) rotate independently. The shape of the scraper blade (32) is adapted to the curvature of the inner wall of the bottom of the cylinder (1). The scraper blade (32) is integrally formed with a shovel blade (321) and a cutting blade (322) with an inclined slope. The scraper blade (32) has several discharge holes (323) on its plate surface.

3. The PMI foam raw material mixing and stirring tank according to claim 2, characterized in that: The switching pressure driving mechanism (5) also includes a spacer bearing (53), a support frame (54), a pressure spring (55), and a switching cylinder (56). The spacer bearing (53) is installed between the switching drive shaft (52) and the scraper blade. The spacer bearing (53) isolates the transmission of rotational torque, so that when the scraper blade (32) rotates with the inner drive shaft (31), the rotational torque will not be transmitted to the switching drive shaft (52). The switching drive shaft (52) only makes up-down linear displacement movement and does not follow the rotation.

4. The PMI foam raw material mixing and stirring tank according to claim 1, characterized in that: A pressure spring (55) is symmetrically arranged between the bottom of the cylinder (1) and the switching drive shaft (52). The pressure spring (55) always applies a constant downward preload force to the switching drive shaft (52). A switching cylinder (56) is fixedly installed at the bottom of the cylinder body (1) by a support frame (54), and the telescopic end of the switching cylinder (56) is fastened to the switching transmission shaft (52).

5. The PMI foam raw material mixing and stirring tank according to claim 3, characterized in that: The drive assembly (4) includes a main motor (41) and a scraper motor (42). Two sets of transmission gears (411) are fixedly sleeved on the output shaft of the main motor (41). The top end of the outer sleeve transmission shaft (21) is integrally formed with a transmission gear ring (211). The transmission gear ring (211) meshes and matches with the corresponding transmission gear (411) on the output shaft of the main motor (41). The gear ratio between the transmission gear (411) on the output shaft of the main motor (41) and the transmission gear ring (211) at the top of the outer sleeve transmission shaft (21) is 1:

1.

6. The PMI foam raw material mixing and stirring tank according to claim 5, characterized in that: An axial transmission block (33) is axially movable on the upper part of the inner transmission shaft (31), and a force-applying spring (34) is installed between the inner transmission shaft (31) and the axial transmission block (33). The force-applying spring (34) always applies an upward axial preload to the axial transmission block (33). The axial transmission block (33) has a secondary gear (35) at its top. Another set of transmission gears (411) on the output shaft of the main motor (41) and the secondary gear (35) are set to mesh with each other in a non-equal gear ratio and the transmission ratio is greater than 1:1, so that the rotational speed of the inner transmission shaft (31) is higher than that of the outer sleeve transmission shaft (21). The top of the axial transmission block (33) and the bottom of the secondary gear (35) are both provided with matching ratchet meshing grooves (36). Through the meshing of the ratchet meshing grooves (36), the rotational torque of the main motor (41) is transmitted to the secondary gear (35) and the axial transmission block (33) in sequence, and finally drives the inner transmission shaft (31) to rotate synchronously. The axial transmission block (33) can complete the axial displacement with the inner transmission shaft (31).

7. The PMI foam raw material mixing and stirring tank according to claim 6, characterized in that: The top of the axial transmission block (33) is provided with a transmission slot (331), and the output shaft of the scraper motor (42) is axially slidably fitted with a rotating protruding force transmission rod (43), and the rotating protruding force transmission rod (43) is provided with a matching limiting positioning block (44). The scraper motor (42) can drive the rotating protruding force transmission rod (43) to rotate circumferentially. Through the limiting and positioning block (44), the rotating protruding force transmission rod (43) can rotate clockwise and synchronously generate an axial downward protruding action. The lower end structure of the rotating protruding force transmission rod (43) is matched and engaged with the transmission groove (331) on the top of the axial transmission block (33). The axial floating tolerance margin is formed by the force spring (34) between the inner transmission shaft (31) and the axial transmission block (33). At the same time, the ratchet meshing groove (36) between the secondary gear (35) and the axial transmission block (33) can be disengaged by the downward movement of the rotating protruding force transmission rod (43), cutting off the original power transmission and thus forming an independent power path.

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