A device and process for producing dried bean curd by continuously point-pulping with a gradient concentration coagulant

Abstract

The application discloses a kind of gradient concentration coagulant continuous point slurry's dried beancurd production device and process, belong to the technical field of soy products processing.The device contains linear conveying mechanism and star type material shifting carousel, multiple groups of stations are arranged circumferentially to carousel, and independent point slurry station of low, medium, high concentration is arranged in turn, each station is equipped with quantitative feeding device, and different concentration coagulant can be quantitatively filled.Slurry feeding barrel is built-in stirring member, each station is matched with non-contact magnetic drive mechanism, and traditional in-penetration mechanical stirring mode is discarded, and there is no health dead angle.The application realizes the progressive uniform gel of soybean milk by three-stage gradient coagulation and staged stirring speed, effectively solves the problems of single-concentration coagulation unevenness, stirring easily causing pollution and parameter unable to be independently regulated existing in the existing carousel type point slurry equipment, the equipment is compact in layout, high in filling precision, good in cleanliness, can significantly improve dried beancurd quality and production efficiency, and is suitable for large-scale continuous production.

Description

Technical Field

[0001] This invention belongs to the technical field of soybean product processing equipment, specifically relating to a continuous bean curd production device for gradient concentration coagulant based on a star-shaped turntable multi-station layout, and the bean curd production process implemented using this device. Background Technology

[0002] Coagulation is a core process in the production of dried tofu that determines the texture, taste, and yield of the finished product. The principle is to use a coagulant to cause soybean protein to undergo a gel reaction to form bean curd. The concentration control, stirring method, and production continuity of the coagulation directly affect the quality of the final product and production efficiency.

[0003] Existing bean curd coagulation production mainly falls into two categories: intermittent and continuous. Intermittent single-tank coagulation offers flexible operation but suffers from low production efficiency and poor batch quality stability. Continuous linear tank coagulation boasts high production efficiency but requires a large equipment footprint and lacks flexibility in concentration gradient control. To balance production efficiency and compact layout, the industry has gradually developed rotary continuous coagulation equipment. For example, Chinese patent document CN108740057A discloses a multi-head mobile continuous coagulation device. This device features a continuous conveyor line and a coagulation mechanism with a rotary table. Multiple sets of liquid dispensing and stirring components are evenly arranged on the rotary table. The conveyor line has a semi-circular coagulation area, where the liquid dispensing and stirring components can move synchronously with the delivery tank, completing the coagulation operation while conveying the liquid. This improves the continuity and compactness of the coagulation process to a certain extent.

[0004] However, the existing technologies mentioned above still have two core technological shortcomings, which cannot meet the production needs of higher quality dried bean curd: Firstly, it cannot achieve graded gradient coagulation. This scheme uses a single coagulation tank to supply coagulant to all dispensing components. The entire coagulation process can only use the same concentration of coagulant, which is a single-concentration, one-time coagulation mode. It cannot add coagulant in stages according to low, medium, and high concentration gradients. Under the action of a single concentration coagulant, soy milk protein is prone to problems such as excessively rapid surface coagulation and insufficient internal reaction. The finished dried tofu has uneven texture inside and out, making it difficult to optimize the gel structure of the soy milk through gradient coagulation technology, thereby improving the elasticity and water retention of the dried tofu.

[0005] Secondly, the immersion-type mechanical agitator poses hygiene risks and lacks control flexibility. This solution uses an agitator shaft with agitator blades that extends into the slurry for agitation. The agitator shaft is in constant contact with the sealed structure, which can easily lead to residual soybean protein, creating unsanitary areas. This makes cleaning and disinfection difficult and fails to meet the clean production requirements for high-grade food products. In addition, the entire agitator drive and lifting mechanism are integrated with the turntable, and the agitation parameters at all points are completely identical. It is impossible to independently match the agitator speed for different coagulation stages. Furthermore, the turntable integrates multiple power and lifting components, resulting in a complex overall structure and high maintenance costs.

[0006] In summary, existing rotary dispensing equipment cannot simultaneously achieve graded dispensing of gradient concentrations and non-contact hygienic mixing, which has become a key technical bottleneck restricting the improvement of quality and efficiency in dried bean curd production. Summary of the Invention

[0007] To address the shortcomings of the existing technology, this invention provides a tofu production device with continuous dispensing of gradient concentration coagulant. By using a star-shaped turntable with multiple independent dispensing stations of different concentrations arranged circumferentially, and combined with a non-contact, multi-station stirring structure, it achieves graded gradient coagulation and clean production in a compact layout.

[0008] The device includes a slurry feeding cylinder and a conveying mechanism for conveying the slurry feeding cylinder.

[0009] The conveying mechanism includes a feeding conveying section and a discharging conveying section arranged in a straight line. A star-shaped material feeding turntable that can rotate intermittently is provided on the same side of the connection between the feeding conveying section and the discharging conveying section.

[0010] Along the rotation direction of the star-shaped material feeding turntable, there are low-concentration slurry application stations, medium-concentration slurry application stations, and high-concentration slurry application stations arranged in sequence. Each slurry application station is equipped with an independent quantitative supply device that outputs the corresponding concentration of coagulant.

[0011] The star-shaped feeding turntable is provided with multiple arc-shaped bearing positions that are adapted to the outer wall of the feeding cylinder. During the intermittent rotation of the star-shaped feeding turntable, the feeding cylinder of the feeding conveying section is connected to the arc-shaped bearing position in sequence, and the feeding cylinder is driven to stop at each slurry point station one by one. Finally, the feeding cylinder that has completed slurrying is moved to the output conveying section for output.

[0012] The slurry delivery cylinder is equipped with a rotatable stirring component inside, and each slurry dispensing station is equipped with a non-contact drive mechanism. When the slurry delivery cylinder stops at any slurry dispensing station, the quantitative supply device of that slurry dispensing station adds a coagulant of the corresponding concentration into the slurry delivery cylinder, while the non-contact drive mechanism drives the stirring component to rotate inside the slurry delivery cylinder in a non-mechanical contact manner.

[0013] Furthermore, the arc-shaped bearing positions are set to five, evenly distributed along the circumference of the star-shaped material feeding turntable, corresponding to the feeding station, low-concentration slurry application station, medium-concentration slurry application station, high-concentration slurry application station, and unloading station respectively; the angle of each intermittent rotation of the star-shaped material feeding turntable corresponds to the step distance of one station, the feeding conveying section is connected to the feeding station, and the discharging conveying section is connected to the unloading station.

[0014] Furthermore, the stirring component is a magnetic stirrer, and the bottom center of the slurry delivery cylinder is recessed inward to form a positioning and receiving groove, in which the magnetic stirrer is housed.

[0015] Furthermore, the non-contact drive mechanism is a magnetic actuator, which includes a drive housing with a limiting component. A drive motor is fixed inside the drive housing by a mounting bracket, and a strong magnet is mounted on the output shaft of the drive motor. The magnetic actuator is positioned below the stop position of the slurry delivery cylinder in the slurry station by the limiting component of the drive housing, and the strong magnet is magnetically attracted to the magnetic stirrer.

[0016] Furthermore, each of the aforementioned slurry application stations is equipped with a screw lifting frame via a vertical frame, and the quantitative supply device is mounted on the screw lifting frame; the screw lifting frame can be raised and lowered vertically along the vertical frame to adjust the filling height of the quantitative supply device.

[0017] Furthermore, the quantitative supply device includes a coagulant storage chamber and a piston-type dispensing chamber, which are connected by a suction pipe equipped with a first solenoid valve. The suction pipe is also connected to a feeding pipe equipped with a second solenoid valve. A piston is installed in the piston-type dispensing chamber, and a lifting drive mechanism is connected to the piston. The lifting drive mechanism drives the piston to reciprocate linearly along the inner wall of the piston-type dispensing chamber.

[0018] Furthermore, the lifting drive mechanism includes a transmission screw that also serves as a piston shaft, with its lower end fixedly connected to the piston; a lead screw sleeve is fitted over the shaft of the transmission screw, and the lead screw sleeve is connected to the servo motor via a transmission assembly; the transmission assembly includes a worm gear fixedly fitted on the outer wall of the lead screw sleeve and a worm coaxially fixed to the output shaft of the servo motor, the worm gear meshing with the worm gear for transmission, and the lower end face of the worm gear being axially supported and positioned by a thrust bearing.

[0019] Furthermore, each of the feeding station, low-concentration slurry application station, medium-concentration slurry application station, and high-concentration slurry application station is equipped with a positioning detection mechanism; guide wheel frames are provided between the feeding conveyor section and the feeding station, and between the discharging conveyor section and the unloading station, for lateral guidance and limiting of the slurry cylinder entering and exiting the star-shaped material feeding turntable.

[0020] Furthermore, the device also includes a PLC control system, which is electrically connected to the conveying mechanism, the rotating motor of the star-shaped material feeding turntable, each quantitative supply device, each non-contact drive mechanism, and each arrival detection mechanism, and is used for linkage control of conveying start and stop, intermittent rotation of the star-shaped material feeding turntable, quantitative addition of coagulant, and stirring start and stop.

[0021] Another aspect of the present invention provides a continuous coagulant feeding process for making dried bean curd, using the aforementioned apparatus to complete the entire process, specifically including the following steps: S1 feeding: The feeding cylinder containing preheated soy milk is conveyed through the feeding conveyor section, guided by the guide wheel frame and connected to the arc-shaped bearing position of the star-shaped feeding turntable. After the arrival detection mechanism triggers the signal, the star-shaped feeding turntable starts intermittent rotation. S2 Low Concentration Coagulation: The star-shaped material feeding turntable drives the slurry delivery cylinder to rotate to the low concentration slurry station and stop. After the arrival detection mechanism triggers the signal, the quantitative supply device at this station adds low concentration coagulant into the slurry delivery cylinder. At the same time, the non-contact drive mechanism drives the stirring component to rotate at the first speed to complete the pre-coagulation operation. S3 Medium Concentration Coagulation: The star-shaped material feeding turntable rotates intermittently again, driving the slurry delivery cylinder to stop at the medium concentration slurry point. After the arrival detection mechanism triggers the signal, the quantitative supply device at this station adds medium concentration coagulant into the slurry delivery cylinder. At the same time, the non-contact drive mechanism drives the stirring component to rotate at the second speed to complete the main coagulation operation. S4 High Concentration Coagulation: The star-shaped material feeding turntable rotates intermittently again, driving the slurry delivery cylinder to stop at the high concentration slurry point. After the arrival detection mechanism triggers the signal, the quantitative supply device at this station adds high concentration coagulant into the slurry delivery cylinder. At the same time, the non-contact drive mechanism drives the stirring component to rotate at the third speed to complete the three-stage gradient coagulation operation. S5 feeding: The star-shaped feeding turntable drives the feeding cylinder, which has completed gradient slurry application, to rotate to the feeding station. After being guided by the guide wheel frame, the feeding cylinder is moved to the discharge conveyor section and output to the subsequent pressing and forming process.

[0022] Compared with the prior art, the present invention has the following significant advantages: 1. Achieving graded gradient coagulation to improve the quality of finished dried bean curd. This device uses a star-shaped feed turntable with three circumferentially arranged feeding stations equipped with independent coagulant concentrations. A single tank of soy milk stops sequentially at the low, medium, and high concentration stations as the turntable rotates, completing the graded feeding of coagulant and achieving gradual gradient coagulation. This allows the soybean protein to gradually form a uniform gel structure from the surface to the interior, avoiding the problems of over-coagulation on the surface and undercooked interior that are prone to occur with single-concentration feeding. This effectively improves the elasticity, water retention, and texture uniformity of the dried bean curd. Furthermore, each station is independently equipped with a quantitative supply device, which can flexibly adjust the concentration and amount of coagulant at each level to adapt to the process requirements of different types of dried bean curd.

[0023] 2. Non-contact stirring, balancing clean production requirements with control flexibility. This device uses a non-contact drive mechanism to rotate the stirring components inside the slurry delivery cylinder. No mechanical structure extends into the slurry, completely eliminating sanitary dead zones caused by the stirring shaft and seals. The slurry delivery cylinder can be directly cleaned and disinfected as a whole, fully meeting the requirements of high-level clean food production. The drive mechanism is fixedly installed at each slurry station and does not need to rotate with the turntable, greatly simplifying the turntable structure, reducing maintenance costs, and allowing each station to independently set stirring parameters, precisely matching the stirring needs of different coagulation stages.

[0024] Based on this, the piston-type quantitative injection structure can further improve the accuracy of coagulant injection and ensure the consistency of gradient parameters of each batch of products; the screw lifting frame can be adapted to slurry cylinders of different heights and specifications, improving the equipment's versatility; the arrival detection and control system can realize fully automated operation, reduce labor costs, and ensure stable production cycle. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the overall isometric structure of the device of the present invention (I); Figure 2 This is a schematic diagram (II) of the overall isometric structure of the device of the present invention; Figure 3 This is a schematic diagram (III) of the overall isometric structure of the device of the present invention; Figure 4 A top view of the slurry delivery cylinder in conjunction with the non-contact drive mechanism; Figure 5 for Figure 4 A cross-sectional view along the AA direction; Figure 6 This is a schematic diagram of a non-contact drive mechanism. Figure 7 Schematic diagram of the internal transmission structure of the quantitative supply device (I); Figure 8 Schematic diagram of the internal transmission structure of the quantitative supply device (II); Explanation of reference numerals in the attached figures: 1-Pulp feeding cylinder; 101-Positioning receiving tank; 2-Conveying mechanism; 201-Feeding conveying section; 202-Discharge conveying section; 3-Star-shaped material feeding turntable; 301-Arc-shaped bearing position; 4-Quantitative supply device; 401-Coagulant storage chamber; 402-Piston-type batching chamber; 403-Extraction pipeline; 404-Feeding pipeline; 405-Piston; 406-Lifting drive mechanism; 4061-Transmission screw; 4062-Screw sleeve; 4063-Servo motor; 4064-Worm gear; 4065-Worm; 5-Agitating component; 6-Non-contact drive mechanism; 601-Limiting component; 602-Drive housing; 603-Mounting bracket; 604-Drive motor; 605-Strong magnet; 7-Vertical frame; 8-Screw lifting frame; 9-Position detection mechanism; 10-Guide wheel frame. Detailed Implementation

[0027] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for 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 the invention. Unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly, and can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] like Figures 1 to 7 As shown in the figure, the bean curd production device for continuous slurry application of gradient concentration coagulant described in this embodiment adopts a layout of linear conveying combined with circumferential rotation. It mainly consists of a slurry feeding cylinder 1, a conveying mechanism 2, a star-shaped material feeding turntable 3, a quantitative supply device 4, a stirring component 5, a non-contact drive mechanism 6, a vertical frame 7, a screw lifting frame 8, a positioning detection mechanism 9, and a guide wheel frame 10. The whole device is equipped with a PLC control system to achieve fully automated linkage operation.

[0030] The conveying mechanism 2 adopts a food-grade stainless steel chain or roller conveyor structure, divided into a feeding conveying section 201 and a discharging conveying section 202. The two sections are arranged sequentially along the same straight line. The feeding conveying section 201 is used to convey the discharging cylinder 1 containing raw soybean milk, while the discharging conveying section 202 is used to output the discharging cylinder 1 after discharging. The conveying speed of the two sections can be independently adjusted by the control system to match the overall production rhythm. A star-shaped material feeding turntable 3 is installed on the same side of the connection between the feeding conveying section 201 and the discharging conveying section 202. The star-shaped material feeding turntable 3 is a star-shaped wheel structure, with a reduction gear motor connected to the center through a rotating shaft. It is driven by pulse signals sent by the control system to perform intermittent rotary motion, with each rotation angle precisely corresponding to the workstation step distance.

[0031] Five concave arc-shaped support positions 301 are evenly arranged along the circumferential edge of the star-shaped material feeding turntable 3. The inner radius of the arc-shaped support position 301 is adapted to the outer wall radius of the slurry feeding cylinder 1, which can stably support the cylinder body of the slurry feeding cylinder 1 from the side and prevent the cylinder body from shaking or tipping over during rotation. The five arc-shaped support positions 301 correspond sequentially to the feeding station, low-concentration slurry application station, medium-concentration slurry application station, high-concentration slurry application station, and unloading station along the circumference of the turntable. The included angle between the centers of adjacent stations is 72°, corresponding to the step angle of each intermittent rotation of the star-shaped material feeding turntable 3. The feeding station is aligned with the end position of the feeding conveyor section 201, and the unloading station is aligned with the beginning position of the discharging conveyor section 202. During the intermittent rotation of the turntable, the feeding station simultaneously completes the slurry feeding cylinder connection, the three slurry application stations simultaneously complete the slurry application operation of the corresponding concentration, and the unloading station simultaneously completes the slurry feeding cylinder delivery. The five stations operate in parallel, resulting in a compact and efficient production cycle. Guide wheel frames 10 are installed at the connection between the feeding conveyor section 201 and the loading station, and at the connection between the discharging conveyor section 202 and the unloading station. The guide wheel frame 10 includes mounting strips arranged on both sides of the feeding conveyor section 201 and the discharging conveyor section 202. Multiple freely rotatable nylon guide rollers are installed on the mounting strips at intervals along the conveying direction. The spacing between the rollers on both sides is matched with the outer diameter of the slurry cylinder 1. When the slurry cylinder 1 enters or exits the turntable, the side wall of the roller abuts against the outer wall of the cylinder for lateral limiting, ensuring that the cylinder is accurately inserted into the arc-shaped bearing position 301, and avoiding conveying deviation that causes jamming.

[0032] Along the rotation direction of the star-shaped material feeding turntable 3, three independent dispensing stations for low, medium, and high concentrations are sequentially set between the feeding and unloading stations. Each dispensing station is fixedly equipped with a vertical frame 7, which is welded from steel and fixed to the base platform of the equipment. Each vertical frame 7 is equipped with a screw lifting frame 8. The bearing platform of the screw lifting frame 8 is used to install the quantitative supply device 4. The screw lifting frame 8 can be raised and lowered along the vertical guide rail of the vertical frame by manual crank or electric drive, thereby adjusting the overall height of the quantitative supply device 4 so that the filling port can be adapted to the dispensing cylinder 1 of different height specifications, improving the versatility of the equipment. Each of the three dispensing stations is equipped with an independent quantitative supply device 4, which stores low, medium, and high concentrations of coagulant respectively, and the dispensing action is controlled independently without interference.

[0033] like Figure 7 , Figure 8As shown, the quantitative supply device 4 mainly consists of a coagulant storage chamber 401, a piston-type dispensing chamber 402, a suction pipe 403, a feeding pipe 404, a piston 405, and a lifting drive mechanism 406. The coagulant storage chamber 401 is a sealed storage container used to store coagulant concentrate of the corresponding work station concentration. Its lower outlet is connected to the suction pipe 403, which is equipped with a first solenoid valve. The end of the pipe is connected to the upper cavity of the piston-type dispensing chamber 402. The suction pipe 403 branches off between the first solenoid valve and the piston-type dispensing chamber and connects to the feeding pipe 404, which is equipped with a second solenoid valve. The outlet of the pipe bends downwards, facing the center of the cylinder opening of the lower slurry cylinder 1. The piston-type dispensing chamber 402 is a vertically arranged precision cylindrical cavity with a smooth and sealed inner wall. A piston 405 is installed inside, and a sealing ring is installed around the piston 405 to tightly fit the inner wall of the cavity. A lifting drive mechanism 406 is connected to the center of the top surface of the piston 405, which drives it to perform vertical reciprocating linear motion along the inner wall of the cavity. Specifically, an exhaust structure is provided on the upper section of the piston-type dispensing chamber 402, which can be an exhaust hole or an exhaust gap.

[0034] The lifting drive mechanism 406 adopts a precision transmission structure of worm gear and lead screw, specifically including a transmission lead screw 4061, a lead screw sleeve 4062, a servo motor 4063, a worm gear 4064, and a worm 4065. The transmission lead screw 4061 also serves as a piston shaft, with its lower end fixedly connected to the center of the top surface of the piston 405. The rod extends upward through the top wall of the piston-type dispensing chamber 402, and a dynamic sealing structure is provided at the protrusion position to ensure the chamber is sealed. The lead screw 4061 is fitted with a lead screw sleeve 4062, the inner wall of which is machined with internal threads, meshing with the external threads of the transmission lead screw 4061 to form a lead screw transmission pair. When the lead screw sleeve 4062 rotates, it can drive the transmission lead screw 4061 to perform vertical linear motion. The outer wall of the nut sleeve 4062 is fixedly fitted with a worm gear 4064. The servo motor 4063 is horizontally fixedly installed on the device housing. The worm 4065 is coaxially fixedly installed on its output shaft. The worm gear 4064 and the worm 4065 mesh with each other to form a reduction transmission pair, which can reduce the high-speed rotation of the servo motor and transmit it to the nut sleeve.

[0035] The lower end face of the worm gear 4064 is axially supported and positioned by a thrust bearing. The thrust bearing is installed on the support seat of the device housing and bears the axial load caused by the piston movement, preventing axial movement between the worm gear and the nut sleeve during transmission, thus ensuring transmission accuracy and structural stability.

[0036] The specific working process of quantitative injection is as follows: In the material extraction stage, the first solenoid valve is opened and the second solenoid valve is closed. The servo motor 4063 rotates in the forward direction, which drives the worm wheel 4064 and the screw sleeve 4062 to rotate in the forward direction through the worm 4065. This drives the transmission screw 4061 to drive the piston 405 to move upward at a constant speed. The volume of the lower chamber of the piston-type batching chamber 402 increases, forming a negative pressure. The coagulant in the coagulant storage chamber 401 is sucked into the piston-type batching chamber 402 through the material extraction pipe 403. In the injection stage, the first solenoid valve is closed and the second solenoid valve is opened. The servo motor 4063 rotates in the reverse direction, which drives the transmission screw 4061 to drive the piston 405 to move downward at a constant speed. The piston squeezes the coagulant in the chamber, so that the coagulant is quantitatively injected into the lower slurry cylinder 1 through the feeding pipe 404. By precisely controlling the rotation number and speed of the servo motor through the control system, the lifting stroke and movement speed of the piston can be accurately controlled, thereby precisely controlling the volume and rate of coagulant added each time. The metering accuracy is not affected by pipeline pressure or liquid level fluctuations, ensuring the stability of the gradient coagulation process.

[0037] like Figures 4 to 6 As shown, each feeding cylinder 1 is a cylindrical structure made of food-grade stainless steel. The cylinder contains the soy milk to be coagulated. A freely rotatable stirring component 5 is installed at the bottom of the cylinder. In this embodiment, the stirring component 5 is a columnar magnetic stir bar, covered with a food-grade polytetrafluoroethylene layer and encapsulated with a permanent magnet core. The center of the bottom of the feeding cylinder 1 is recessed inward to form a circular positioning and receiving groove 101. The magnetic stir bar is placed in the positioning and receiving groove 101. The inner diameter of the positioning and receiving groove 101 is slightly larger than the length of the magnetic stir bar, which can radially limit the rotation center of the stir bar to prevent the stir bar from deviating during the stirring process and ensure the stability of the magnetic coupling transmission and the accuracy of the stirring center.

[0038] Directly below the stopping position of the slurry delivery cylinder 1 at each slurry dispensing station, an independent non-contact drive mechanism 6 is installed. In this embodiment, this mechanism is an external magnetic actuator. The magnetic actuator includes a drive housing 602, with limiting members 601 on both outer walls of the drive housing 602. The limiting members 601 can be positioning pins or snap-fit ​​structures. The actuator is fixedly mounted on the mounting base of the station by the limiting members 601, ensuring that the rotation center of the actuator is precisely aligned vertically with the center of the positioning receiving groove 101 of the upper slurry delivery cylinder 1. Inside the drive housing 602, a drive motor 604 is fixedly installed by a mounting bracket 603. The output shaft of the drive motor 604 is vertically upward, and a strong magnet 605 is fixedly installed at the end of the shaft. The strong magnet 605 is a neodymium iron boron permanent magnet, and its magnetic field strength can penetrate the top wall of the drive housing 602 and the bottom of the stainless steel cylinder to form effective magnetic coupling with the magnetic stir bar inside the cylinder. Specifically, the drive housing 602 is made of non-magnetic stainless steel or engineering plastic to ensure effective magnetic field penetration without affecting food hygiene and safety.

[0039] When the feeding cylinder 1 stops at the corresponding feeding station along with the turntable, the drive motor 604 drives the strong magnet 605 to rotate at a uniform speed. The rotating magnetic field passes through the top wall of the drive housing 602 and the bottom wall of the feeding cylinder, and drives the magnetic stir bar inside the cylinder to rotate synchronously through magnetic attraction, thereby realizing the mixing and stirring of soybean milk and coagulant. No mechanical parts extend into the slurry during the entire stirring process, completely avoiding contamination of the slurry by mechanical structures. The feeding cylinder can directly enter the cleaning process as a whole, ensuring thorough cleaning without any blind spots. The rotation speed of the magnetic drive at the three feeding stations can be independently adjusted by the control system. The low-concentration feeding station uses a lower speed to ensure uniform dispersion of the coagulant while avoiding local over-coagulation, protecting the initially formed soybean curd structure; the medium-concentration station uses a medium speed to ensure sufficient and uniform coagulation reaction; and the high-concentration station uses a higher speed to ensure complete final coagulation. By matching the different speeds to the different concentrations, the optimal coagulation effect is achieved.

[0040] Each of the feeding, low-concentration, medium-concentration, and high-concentration slurry dispensing stations is equipped with a positioning detection mechanism 9 on its side. This mechanism uses a diffuse reflection photoelectric sensor, with its detection end facing the arc-shaped bearing position 301 of the station. It is used to detect whether the slurry delivery cylinder 1 has stopped in place at the corresponding station and transmits the detection signal to the control system in real time. The unloading station can also be equipped with a positioning detection mechanism 9 to confirm whether the slurry delivery cylinder that has completed slurry dispensing has accurately moved to the discharge conveyor section 202, preventing unloading failure or equipment interference due to turntable positioning deviation.

[0041] The entire device is equipped with a PLC control system as its core. The control system is electrically connected to the conveyor motor of the conveying mechanism 2, the rotating motor of the star-shaped material feeding turntable 3, the solenoid valves and servo motors of each quantitative supply device 4, the drive motors of each non-contact drive mechanism 6, and each arrival detection mechanism 9. The system controls the actions of each component in a coordinated manner according to a preset production rhythm. The specific linkage logic is as follows: the feeding conveyor section continuously conveys the slurry cylinder. After the arrival detection mechanism of the feeding station detects that the slurry cylinder has arrived, the control system controls the feeding conveyor section to stop briefly and simultaneously controls the star-shaped material feeding turntable to rotate one step. After the arrival detection mechanism of each slurry station detects that the slurry cylinder has arrived, it sequentially controls the quantitative supply device of the corresponding station to complete the quantitative filling and the non-contact drive mechanism to start stirring. After the set stirring time is reached, stirring stops and waits for the next rotation signal. The slurry cylinder of the unloading station is pushed to the discharge conveyor section with the rotation action and output to the downstream process.

[0042] The production of dried tofu using the above-mentioned device with continuous coagulant concentration gradient is carried out according to the following steps: S1 Feeding: The soybean milk, which has been preheated to the process temperature after the boiling and screening processes, is poured into a clean feeding cylinder 1. The feeding cylinder 1 is conveyed to the star-shaped feeding turntable 3 along with the feeding conveyor section 201. After being guided and corrected laterally by the feeding side guide wheel frame 10, the cylinder is accurately inserted into the arc-shaped bearing position 301 of the feeding station. After the positioning detection mechanism 9 of the feeding station detects that the cylinder is in place, it sends a trigger signal to the control system. The control system controls the star-shaped feeding turntable 3 to start, and it rotates intermittently by 72° to complete one step of rotation, moving the feeding cylinder to the low-concentration feeding station.

[0043] S2 Low-concentration coagulation: The star-shaped feed turntable 3 drives the feeding cylinder 1 to rotate and stop at the low-concentration feeding station. The arrival detection mechanism 9 of this station detects that the cylinder is in place and sends a signal. The quantitative supply device 4 of the low-concentration station adds low-concentration coagulant into the feeding cylinder 1 according to the preset dosage. At the same time, the non-contact drive mechanism 6 of this station is started, driving the stirring component 5 to rotate at the first speed, so that the low-concentration coagulant is evenly mixed with the soy milk, completing the pre-coagulation of the soy milk. Stirring stops after the set stirring time is reached.

[0044] S3 Medium Concentration Coagulation: After the pre-coagulation operation is completed, the star-shaped feed turntable 3 rotates intermittently by 72° again, driving the feed cylinder 1 to rotate to the medium concentration feed station and stop. After the arrival detection is confirmed, the quantitative supply device 4 of the medium concentration station adds medium concentration coagulant to the feed cylinder 1 according to the preset dosage. At the same time, the non-contact drive mechanism 6 drives the stirring component 5 to rotate at the second speed, so that the medium concentration coagulant is fully mixed with the pre-coagulated soy milk, and the main coagulation operation of the soy milk is completed. Stirring stops after the set stirring time is reached.

[0045] S4 High-Concentration Coagulation: After the main coagulation operation is completed, the star-shaped material feeding turntable 3 rotates intermittently by 72° again, driving the slurry delivery cylinder 1 to rotate and stop at the high-concentration slurry point. After the arrival detection is confirmed, the quantitative supply device 4 at the high-concentration point adds high-concentration coagulant to the slurry delivery cylinder 1 according to the preset dosage. At the same time, the non-contact drive mechanism 6 drives the stirring component 5 to rotate at the third speed to complete the three-stage gradient coagulation operation. Stirring stops after the set stirring time is reached. In this embodiment, the first speed < the second speed < the third speed. The progressively increasing stirring speed matches the progressively increasing coagulant concentration, which ensures that the bean curd is not sheared and broken in the early stage and that the coagulation reaction is fully and uniformly carried out at the high concentration in the later stage.

[0046] S5 feeding: After the three-stage gradient slurry is completed, the star-shaped feeding turntable 3 continues to rotate intermittently by 72°, driving the feeding cylinder 1 to rotate to the feeding station; under the pushing force of the turntable and the guiding action of the discharge side guide wheel frame 10, the feeding cylinder 1 is smoothly moved from the arc-shaped bearing position 301 to the discharge conveying section 202, and is output to the subsequent slurry, pressing, molding and brining processes along with the discharge conveying section 202.

[0047] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be covered within the protection scope of the present invention.

Claims

1. A bean curd production apparatus for continuous dispensing of a gradient concentration coagulant, comprising a dispensing cylinder (1) and a conveying mechanism (2) for conveying the dispensing cylinder (1), characterized in that: The conveying mechanism (2) includes a feeding conveying section (201) and a discharging conveying section (202) arranged in a straight line. A star-shaped material feeding turntable (3) that can rotate intermittently is provided on the same side of the connection between the feeding conveying section (201) and the discharging conveying section (202). Along the rotation direction of the star-shaped material feeding turntable (3), there are low-concentration slurry stations, medium-concentration slurry stations and high-concentration slurry stations arranged in sequence, and each slurry station is equipped with a quantitative supply device (4) that independently outputs the corresponding concentration of coagulant. The star-shaped feeding turntable (3) is provided with multiple arc-shaped bearing positions (301) that are adapted to the outer wall of the feeding cylinder (1) in the circumferential direction. During the intermittent rotation of the star-shaped feeding turntable (3), the feeding cylinder (1) of the feeding conveying section (201) is connected to the arc-shaped bearing position (301) in sequence, and the feeding cylinder (1) is driven to stop at each slurry station one by one. Finally, the feeding cylinder (1) that has completed slurrying is transferred to the discharge conveying section (202) for output. The slurry delivery cylinder (1) is equipped with a rotatable stirring component (5), and each slurry station is equipped with a non-contact drive mechanism (6). When the slurry delivery cylinder (1) stops at any slurry station, the quantitative supply device (4) of that slurry station adds a coagulant of the corresponding concentration into the slurry delivery cylinder (1), and at the same time, the non-contact drive mechanism (6) drives the stirring component (5) to rotate in the slurry delivery cylinder (1) in a non-mechanical contact manner.

2. The bean curd production apparatus for continuous dispensing of gradient concentration coagulant according to claim 1, characterized in that, The arc-shaped bearing position (301) is set to five, which are evenly distributed around the circumference of the star-shaped material feeding turntable (3), respectively corresponding to the feeding station, the low-concentration slurry station, the medium-concentration slurry station, the high-concentration slurry station and the unloading station; the angle of each intermittent rotation of the star-shaped material feeding turntable (3) corresponds to the step distance of one station, the feeding conveying section (201) is connected to the feeding station, and the discharging conveying section (202) is connected to the unloading station.

3. The bean curd production apparatus for continuous dispensing of gradient concentration coagulant according to claim 1, characterized in that, The stirring component (5) is a magnetic stirrer. The bottom center of the slurry delivery cylinder (1) is recessed into the cylinder to form a positioning and receiving groove (101). The magnetic stirrer is housed in the positioning and receiving groove (101).

4. The bean curd production apparatus for continuous dispensing of gradient concentration coagulant according to claim 3, characterized in that, The non-contact drive mechanism (6) is a magnetic actuator, which includes a drive housing (602) with a limiting member (601). A drive motor (604) is fixed inside the drive housing (602) by a mounting bracket (603). A strong magnet (605) is mounted on the output shaft of the drive motor (604). The magnetic actuator is positioned and installed below the stopping position of the slurry delivery cylinder (1) in the slurry station by the limiting member (601) of the drive housing (602). The strong magnet (605) is magnetically attracted to the magnetic stirrer.

5. The bean curd production apparatus for continuous dispensing of gradient concentration coagulant according to claim 1, characterized in that, Each of the above-mentioned slurry stations is equipped with a screw lifting frame (8) via a vertical frame (7), and the quantitative supply device (4) is installed on the screw lifting frame (8); the screw lifting frame (8) can be raised and lowered vertically along the vertical frame (7) to adjust the filling height of the quantitative supply device (4).

6. The bean curd production apparatus for continuous dispensing of gradient concentration coagulant according to claim 5, characterized in that, The quantitative supply device (4) includes a coagulant storage chamber (401) and a piston-type dispensing chamber (402), which are connected by a suction pipe (403) equipped with a first solenoid valve. The suction pipe (403) is also connected to a feeding pipe (404) equipped with a second solenoid valve. A piston (405) is provided in the piston-type dispensing chamber (402), and a lifting drive mechanism (406) is connected to the piston (405). The lifting drive mechanism (406) drives the piston (405) to reciprocate linearly along the inner wall of the piston-type dispensing chamber (402).

7. The bean curd production apparatus for continuous dispensing of gradient concentration coagulant according to claim 6, characterized in that, The lifting drive mechanism (406) includes a transmission screw (4061) that also serves as a piston shaft, with the lower end of the transmission screw (4061) fixedly connected to the piston (405). A screw nut sleeve (4062) is provided on the shaft of the transmission screw (4061), and the screw nut sleeve (4062) is connected to the servo motor (4063) via a transmission assembly. The transmission assembly includes a worm wheel (4064) fixedly sleeved on the outer wall of the screw nut sleeve (4062) and a worm (4065) coaxially fixed to the output shaft of the servo motor (4063). The worm wheel (4064) meshes with the worm (4065) for transmission, and the lower end face of the worm wheel (4064) is axially supported and positioned by a thrust bearing.

8. The bean curd production apparatus for continuous dispensing of gradient concentration coagulant according to claim 2, characterized in that, The loading station, low-concentration slurry loading station, medium-concentration slurry loading station and high-concentration slurry loading station are all equipped with a positioning detection mechanism (9); the feeding conveying section (201) and the loading station and the discharging conveying section (202) and the unloading station are all equipped with guide wheel frames (10) for lateral guidance and limiting of the slurry cylinder (1) entering and exiting the star-shaped material feeding turntable (3).

9. The bean curd production apparatus for continuous dispensing of gradient concentration coagulant according to any one of claims 1-8, characterized in that, It also includes a PLC control system, which is electrically connected to the conveying mechanism (2), the rotating motor of the star-shaped material feeding turntable (3), each quantitative supply device (4), each non-contact drive mechanism (6), and each arrival detection mechanism (9) to control the start and stop of the conveying, the intermittent rotation of the star-shaped material feeding turntable (3), the quantitative addition of coagulant, and the start and stop of the stirring.

10. A process for producing dried bean curd using a gradient concentration coagulant with continuous coagulation, characterized in that, The apparatus according to any one of claims 1-9 comprises the following steps: S1 feeding: The feeding cylinder (1) containing preheated soy milk is conveyed by the feeding conveyor section (201), guided by the guide wheel frame (10) and connected to the arc-shaped bearing position (301) of the feeding station of the star-shaped feeding turntable (3). After the arrival detection mechanism (9) triggers the signal, the star-shaped feeding turntable (3) starts intermittent rotation. S2 Low Concentration Coagulation: The star-shaped material feeding turntable (3) drives the slurry delivery cylinder (1) to rotate to the low concentration slurry station and stop. After the arrival detection mechanism (9) triggers the signal, the quantitative supply device (4) of the station adds low concentration coagulant into the slurry delivery cylinder (1). At the same time, the non-contact drive mechanism (6) drives the stirring component (5) to rotate at the first speed to complete the pre-coagulation operation. S3 Medium Concentration Coagulation: The star-shaped material feeding turntable (3) rotates intermittently again, driving the slurry delivery cylinder (1) to rotate to the medium concentration slurry station and stop. After the arrival detection mechanism (9) triggers the signal, the quantitative supply device (4) of this station adds medium concentration coagulant into the slurry delivery cylinder (1). At the same time, the non-contact drive mechanism (6) drives the stirring component (5) to rotate at the second speed to complete the main coagulation operation. S4 High Concentration Coagulation: The star-shaped material feeding turntable (3) rotates intermittently again, driving the slurry delivery cylinder (1) to rotate to the high concentration slurry station and stop. After the arrival detection mechanism (9) triggers the signal, the quantitative supply device (4) of this station adds high concentration coagulant into the slurry delivery cylinder (1). At the same time, the non-contact drive mechanism (6) drives the stirring component (5) to rotate at the third speed to complete the three-stage gradient coagulation operation. S5 feeding: The star-shaped feeding turntable (3) drives the feeding cylinder (1) that has completed gradient slurry application to rotate to the feeding station. The feeding cylinder (1) is guided by the guide wheel frame (10) and then moved to the discharge conveying section (202) for output to the subsequent pressing and molding process.

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