An ultrasonic cleaning machine for feed pelleting molds and an ultrasonic cleaning method for feed pelleting molds.

Abstract

This invention relates to the field of feed processing equipment cleaning and maintenance technology, and discloses an ultrasonic cleaning machine and method for feed pelleting dies. It addresses the problems of existing die hole unblocking and cleaning methods failing to simultaneously achieve processing efficiency, maintain the original shape, size, and wall condition of the die holes, and ensure the thoroughness and uniformity of feed residue removal from die holes at different locations. The cleaning machine includes a cleaning tank, a die support assembly, an ultrasonic generating assembly, and a relative motion driving assembly. The die support position and the ultrasonic radiation surface jointly define the axial energy-receiving position of the die hole, ensuring that the die hole opening is located within the ultrasonic action zone and opposite the ultrasonic radiation surface. Furthermore, the ray extending axially from the center of the opening intersects the ultrasonic radiation surface. During the cleaning process, the feed pelleting die is driven to move relative to the ultrasonic radiation surface, causing the die holes at different locations to successively pass through the axial energy-receiving position. This method is suitable for cleaning the die holes of ring dies and flat dies.

Description

Technical Field

[0001] This invention relates to the field of feed processing equipment cleaning and maintenance technology, specifically to an ultrasonic cleaning machine for feed pelleting molds and an ultrasonic cleaning method for feed pelleting molds. Background Technology

[0002] Feed pelleting dies are crucial components in feed pelleting equipment, used to form feed ingredients into pellets. Common feed pelleting dies include ring dies and flat dies. Feed pelleting dies typically have a large number of die holes. Feed ingredients pass through these holes under pressure and form pellets. During pelleting, starch, oils, proteins, and other binding components in the feed ingredients are easily squeezed and adhered to or compacted within the die holes. After the equipment stops, the feed residue within the die holes may further solidify due to water loss and cooling, reducing the effective flow cross-section of the die holes or even causing blockage. This increases pelleting resistance, affecting pelleting efficiency and the consistency of the formed feed pellets. Therefore, feed pelleting dies need to be cleaned after a period of use.

[0003] In existing technologies, the machining and cleaning of die holes typically employs mechanical tools such as drill bits and wire brushes. Chinese utility model patent CN203265683U discloses a ring die drilling machine tool, including a frame, a longitudinal feed device, two sets of transverse feed devices, and a spindle device. The spindle device drives the ring die to rotate, while the longitudinal and transverse feed devices drive the drill head to feed relative to the ring die, thereby completing the machining of die holes on different ring layers. This equipment is mainly used for die hole forming, reflecting a technical method of sequentially machining die holes at different positions by driving the ring die to rotate and feeding the drill head relative to the ring die.

[0004] Chinese invention patent application CN111730347A discloses a ring die repair machine and its repair method for feed production. The ring die repair machine includes a ring die roller frame, an internal grinding mill, and a drilling machine. The ring die roller frame supports the ring die via two support transmission bearings and is driven to rotate by a servo motor. When clearing the die holes, a twist drill bit is inserted into the inside of the ring die. Through the rotation of the ring die and the positioning of the drill bit, the drill bit sequentially clears the blocked die holes. This equipment combines ring die support, rotation, and drilling machine positioning to achieve mechanical, hole-by-hole clearing of blocked die holes.

[0005] The aforementioned mechanical processing method requires the drill bit or other mechanical tools to align with and enter each die hole. Since feed pelleting dies have a large number of die holes, and these holes are typically small in diameter and deep, locating and clearing each hole individually requires a considerable processing time. The drill bit and other mechanical tools will also come into contact with the hole opening or wall; if the tool size, positioning accuracy, or feed state is inappropriate, it may affect the shape of the hole opening, the roughness of the hole wall, or the size of the die hole. Furthermore, mechanical clearing usually aims primarily to re-open the die holes, and there may still be instances where feed residue adhering to the hole walls is not thoroughly cleaned.

[0006] Ultrasonic cleaning utilizes the cavitation, microjets, and liquid turbulence generated by ultrasonic vibrations in the cleaning fluid to remove deposits from the surface of the object being cleaned, reducing direct mechanical contact between the cleaning tools and the object. Tank-type ultrasonic cleaning equipment typically uses an ultrasonic transducer coupled to the tank to transmit ultrasonic vibrations to the cleaning fluid, creating an ultrasonic action zone within the fluid. However, placing feed pelleting dies directly into the cleaning tank and applying ultrasonic action does not necessarily guarantee the same cleaning effect for dies in different locations.

[0007] Specifically, multiple orifices on a ring die are distributed along its circumference and axial direction, with orifices at different circumferential positions having different axial orientations. While multiple orifices on a flat die typically have parallel axes, their openings are distributed over a larger area of ​​the disk surface. Simultaneously, the ultrasonic energy in the cleaning fluid is also affected by factors such as the position of the ultrasonic radiating surface, tank boundaries, liquid level, reflection, and propagation distance, resulting in spatial distribution differences. If there is a lack of appropriate distance and directional relationship between the orifice opening and the ultrasonic radiating surface, some orifices may not be within the effective ultrasonic action zone, or ultrasonic vibrations may be difficult to effectively act on the interior of the orifice through the orifice opening. For deeper orifices, this difference can easily lead to residues near the orifice opening having already detached, while residues deep within the orifice or on the orifice wall remain incompletely removed.

[0008] Furthermore, when ultrasonic power is continuously output at a fixed frequency, the structure of the tank and the boundary conditions of the cleaning fluid can create relatively fixed regions of varying intensity within the cleaning fluid, resulting in uneven ultrasonic stimulation of the orifices at different locations. The air bubble clusters formed during continuous ultrasonic stimulation can also obstruct the transmission of subsequent ultrasonic energy. Simultaneously, the degree of wetting and softening of compacted or solidified feed residue within the orifices by the cleaning fluid temperature also affects the softening rate of the residue; when the cleaning fluid temperature is too low, the softening rate of the residue is slow, and temperature fluctuations during the cleaning process can lead to inconsistent cleaning results between different batches. Simply extending the cleaning time or increasing the ultrasonic power cannot fundamentally solve the problem of uneven energy distribution in orifices at different locations and depths. Summary of the Invention

[0009] The purpose of this invention is to provide an ultrasonic cleaning machine and method for feed pelleting molds, in order to solve the problems that existing methods for unblocking and cleaning feed pelleting mold holes cannot simultaneously ensure processing efficiency, maintain the original shape, size and wall condition of the holes, and achieve sufficient and uniform removal of feed residue inside the holes at different locations.

[0010] In a first aspect, an ultrasonic cleaning machine for feed pelleting molds is provided, comprising: a cleaning tank for holding a cleaning liquid; a mold support assembly disposed within the cleaning tank and defining a mold support position for supporting a feed pelleting mold having multiple die holes to be cleaned, such that at least a portion of the die holes on the feed pelleting mold is immersed in the cleaning liquid; and an ultrasonic generating assembly comprising an ultrasonic generator and at least one ultrasonic transducer electrically connected to the ultrasonic generator, and having an ultrasonic radiation surface in contact with the cleaning liquid; the ultrasonic transducer is coupled to the ultrasonic radiation surface for transmitting ultrasonic vibrations through the ultrasonic radiation surface to the cleaning liquid and forming an ultrasonic action zone; the mold support position is defined within the cleaning tank and defined in the cleaning liquid. The ultrasonic radiating surface together defines the axial energy-receiving position of the die hole; when the die hole of the feed pelleting die is located at the axial energy-receiving position, the opening of the die hole facing the ultrasonic radiating surface is opposite to the ultrasonic radiating surface, the distance between the opening and the ultrasonic radiating surface makes the opening located within the ultrasonic action zone, and the ray extending outward from the center of the opening along the axial direction of the die hole intersects the ultrasonic radiating surface; a relative motion drive assembly, which is connected to the die support assembly, is used to drive the feed pelleting die to move relative to the ultrasonic radiating surface during the process of the ultrasonic generating assembly applying ultrasonic action to the cleaning liquid, so that the die holes at different positions on the feed pelleting die pass through the axial energy-receiving position of the die hole successively.

[0011] As an optimization and / or instance of the above-mentioned ultrasonic cleaning machine for feed pelleting molds, the ultrasonic generator is further configured to drive the ultrasonic transducer with a periodically changing output frequency during the process in which the relative motion drive assembly drives the feed pelleting mold to move relative to the ultrasonic radiation surface, so as to form a swept frequency output and output drive power to the ultrasonic transducer in an intermittent pulse manner.

[0012] As an optimization and / or instantiation of the above-mentioned ultrasonic cleaning machine for feed pelleting molds, further: the frequency sweep output has a lower frequency sweep limit and an upper frequency sweep limit, both of which are located in the range of 20kHz to 40kHz; the output frequency of the ultrasonic generator changes periodically between the lower frequency sweep limit and the upper frequency sweep limit, and the difference between the upper frequency sweep limit and the lower frequency sweep limit is 2kHz to 6kHz.

[0013] As an optimization and / or instantiation of the above-mentioned ultrasonic cleaning machine for feed pelleting molds, further: the intermittent pulse mode includes periodically alternating ultrasonic output periods and intermittent periods; the ultrasonic generator stops outputting driving power to the ultrasonic transducer during the intermittent period, or outputs driving power to the ultrasonic transducer at a lower level than that during the ultrasonic output period.

[0014] As an optimization and / or instantiation of the above-mentioned ultrasonic cleaning machine for feed pelleting molds, further: the ultrasonic generating component includes a plurality of ultrasonic transducers, which are spaced apart below the mold support position for transmitting ultrasonic vibrations to the cleaning fluid through the ultrasonic radiation surface; the surfaces of the plurality of ultrasonic transducers facing the mold support position form the ultrasonic radiation surface.

[0015] As an optimization and / or instantiation of the above-mentioned ultrasonic cleaning machine for feed pelleting molds, it further includes a heating assembly, which comprises at least two heating elements disposed in the cleaning tank for heating the cleaning liquid; the at least two heating elements are arranged on both sides of the mold support position, and each heating element is fixed to the cleaning tank by a heating element fixing seat.

[0016] As an optimization and / or instantiation of the above-mentioned ultrasonic cleaning machine for feed pelleting molds, it further includes: a temperature detection element and a control component. The temperature detection element is used to detect the temperature of the cleaning liquid. The control component is electrically connected to the temperature detection element and the heating component, respectively, and is used to control the heating component according to the temperature detected by the temperature detection element, so that the temperature of the cleaning liquid is maintained within a preset temperature range. The control component is also electrically connected to the relative motion drive component and the ultrasonic generator, respectively, and is configured to: when the temperature detection element detects that the temperature of the cleaning liquid is within the preset temperature range, simultaneously control the relative motion drive component to drive the feed pelleting mold to move relative to the ultrasonic radiation surface, and control the ultrasonic generator to output drive power to the ultrasonic transducer, so as to drive the ultrasonic transducer to transmit ultrasonic vibration to the cleaning liquid through the ultrasonic radiation surface.

[0017] As an optimization and / or instantiation of the above-mentioned ultrasonic cleaning machine for feed pelleting molds, further: the ultrasonic radiation surface is a plane; when the mold hole is located in the axial energy-receiving position of the mold hole, the vertical distance from the center of the opening of the mold hole facing the ultrasonic radiation surface to the ultrasonic radiation surface is 10mm to 40mm.

[0018] As an optimization and / or instance of the aforementioned ultrasonic cleaning machine for feed pelleting molds, further: the feed pelleting mold supported by the mold support assembly is a ring mold; the mold support assembly includes two spaced-apart support rollers, the axes of the two support rollers are parallel to each other and parallel to the central axis of the ring mold, the two support rollers are respectively located on the lower sides of the ring mold and jointly support the ring mold, and the outer peripheral surfaces of the two support rollers are respectively in contact with the outer peripheral surface of the ring mold; the relative motion drive assembly is used to drive the two support rollers to rotate in the same direction, so as to drive the ring mold to rotate around its own central axis.

[0019] As an optimization and / or instantiation of the aforementioned ultrasonic cleaning machine for feed pelleting molds, further: both ends of each of the support rollers are supported by bearings on oppositely arranged roller fixing vertical plates; the relative motion drive assembly includes a geared motor, a drive sprocket, two driven sprockets, and a chain; the drive sprocket is connected to the output shaft of the geared motor and is located above the two driven sprockets; the two driven sprockets are coaxially connected to one end of the two support rollers on the same side; the chain is wound around the drive sprocket and the two driven sprockets to simultaneously drive the two support rollers to rotate in the same direction.

[0020] As an optimization and / or instance of the above-mentioned ultrasonic cleaning machine for feed pelleting molds, further: the top of the cleaning tank is open, and an inlet and an outlet are respectively provided on opposite sides of the cleaning tank. The outlet is located near the bottom of the cleaning tank, and a control valve is provided on the inlet and the outlet.

[0021] As an optimization and / or instance of the above-mentioned ultrasonic cleaning machine for feed pelleting molds, further: the feed pelleting mold supported by the mold support assembly is a flat mold; the mold support assembly includes a support platform and a positioning part disposed on the support platform, the support platform is used to support the periphery of the flat mold, and the positioning part is used to restrict the flat mold from moving relative to the support platform in a direction parallel to the surface of the flat mold disk; the relative motion drive assembly is connected to the support platform for driving the support platform to rotate about an axis perpendicular to the surface of the flat mold disk, or to reciprocate in a direction parallel to the surface of the flat mold disk, so that the flat mold moves with the support platform, and the mold holes at different positions on the flat mold pass through the axial energy-receiving positions of the mold holes one after another.

[0022] Secondly, a method for ultrasonic cleaning of feed pelleting molds is provided, comprising: supporting a feed pelleting mold having multiple die holes in a cleaning tank containing a cleaning liquid, such that at least a portion of the die holes on the feed pelleting mold is immersed in the cleaning liquid; transmitting ultrasonic vibrations to the cleaning liquid via an ultrasonic transducer coupled to the ultrasonic radiation surface of an ultrasonic generating component, thereby forming an ultrasonic action zone in the cleaning liquid; during the process of applying ultrasonic action to the cleaning liquid via the ultrasonic transducer, driving the feed pelleting mold to move relative to the ultrasonic radiation surface, such that the die holes at different positions on the feed pelleting mold successively pass through the axially charged position of the die holes; when the die holes of the feed pelleting mold are located at the axially charged position of the die holes, the opening of the die holes facing the ultrasonic radiation surface is opposite to the ultrasonic radiation surface, the distance between the opening and the ultrasonic radiation surface causes the opening to be located within the ultrasonic action zone, and a ray extending outward from the center of the opening along the axial direction of the die hole intersects the ultrasonic radiation surface.

[0023] As an optimization and / or instance of the above-mentioned ultrasonic cleaning method for feed pelleting molds, further: during the process of driving the feed pelleting mold to move relative to the ultrasonic radiation surface, so that the die holes at different positions on the feed pelleting mold pass through the axial energy-receiving positions of the die holes one after another, the ultrasonic transducer is driven by an ultrasonic generator with a periodically changing output frequency, and the driving power is output to the ultrasonic transducer in an intermittent pulse manner; the output frequency of the ultrasonic generator changes periodically between the lower limit frequency and the upper limit frequency of the sweep frequency, both of which are located in the range of 20kHz to 40kHz, and the difference between the upper limit frequency and the lower limit frequency is 2kHz to 6kHz; the intermittent pulse manner includes periodically alternating ultrasonic output periods and intermittent periods, during which the driving power output to the ultrasonic transducer is stopped, or the driving power output to the ultrasonic transducer is lower than that of the ultrasonic output periods.

[0024] As an optimization and / or instance of the above-mentioned ultrasonic cleaning method for feed pelleting molds, further: the cleaning liquid is water; the cleaning liquid is heated to a preset temperature range and the temperature of the cleaning liquid is maintained within the preset temperature range; during the period of maintaining the temperature of the cleaning liquid within the preset temperature range, the ultrasonic generator is controlled to output driving power to the ultrasonic transducer to drive the ultrasonic transducer to transmit ultrasonic vibrations through the ultrasonic radiation surface to the cleaning liquid, and during the process of the ultrasonic transducer transmitting ultrasonic vibrations to the cleaning liquid, the feed pelleting mold is driven to move relative to the ultrasonic radiation surface.

[0025] As an optimization and / or instance of the above-mentioned ultrasonic cleaning method for feed pelleting molds, the preset temperature range is further: 20℃~80℃, preferably 30℃~70℃, and more preferably 50℃~60℃.

[0026] Compared with the prior art, the ultrasonic cleaning machine and method for feed pelleting molds provided by the present invention have at least the following beneficial effects:

[0027] (1) The mold support position and the ultrasonic radiation surface jointly define the axial energy position of the mold hole, and make the opening of the mold hole facing the ultrasonic radiation surface at the axial energy position of the mold hole opposite to the ultrasonic radiation surface, the opening located within the ultrasonic action zone, and the ray extending from the center of the opening along the mold hole axial direction to the outside of the hole intersect with the ultrasonic radiation surface, so that the ultrasonic action can act on the inside of the mold hole from the side opposite to the opening through the opening, reducing the situation where the ultrasonic action deviates from the opening or only acts on the surface of the feed pelleting mold, which is beneficial to remove feed residues in the depth of the mold hole and on the hole wall.

[0028] (2) During the process of the ultrasonic generator applying ultrasonic action to the cleaning fluid, the feed pelleting die is driven to move relative to the ultrasonic radiation surface. This allows the die holes at different positions on the feed pelleting die to pass through the axial energy-receiving positions of the die holes one after another. This reduces the uneven cleaning intensity caused by the spatial distribution differences of the ultrasonic action area, ensuring that the die holes at different positions can all receive effective ultrasonic action, thus improving the coverage and uniformity of the die hole cleaning. The cleaning process mainly relies on the ultrasonic action in the cleaning fluid, eliminating the need for mechanical tools such as drill bits to enter the die holes one by one. Therefore, it can reduce the possibility of mechanical tools causing adverse effects on the orifice, orifice wall, and die hole size.

[0029] (3) By driving the ultrasonic transducer with a periodically varying output frequency, the spatial distribution of the strong and weak areas of ultrasonic action in the cleaning fluid can be changed, reducing the relatively fixed weak action area at a fixed frequency. By outputting the driving power in an intermittent pulse manner, the ultrasonic output period and the intermittent period alternate periodically, which is conducive to the formation and collapse of cavitation bubbles and the exchange of cleaning fluid in the mold hole, and can reduce the shielding effect of the continuously formed bubble group on the ultrasonic energy transmission, thereby improving the peeling effect of feed residue inside the mold hole.

[0030] (4) Multiple ultrasonic transducers are spaced apart below the mold support position, and their surfaces facing the mold support position form an ultrasonic radiation surface, which can expand the coverage of the ultrasonic action on the mold support position. When the ultrasonic radiation surface is a plane, and the vertical distance from the center of the orifice located at the axial energy receiving position of the mold hole to the ultrasonic radiation surface is limited to 10mm to 40mm, it is beneficial to keep the orifice within a distance range suitable for receiving ultrasonic action and improve the stability of different mold hole energy conditions.

[0031] (5) By setting at least two heating components on both sides of the mold support position, the cleaning fluid can be heated from different positions, promoting the wetting and softening of the compacted or solidified feed residue in the mold hole. By maintaining the temperature of the cleaning fluid within a preset temperature range through temperature detection and control components, and simultaneously implementing ultrasonic action and relative movement of the feed pelleting mold under this temperature condition, the impact of cleaning fluid temperature fluctuations on the cleaning effect can be reduced, and the consistency of the cleaning process for different batches can be improved.

[0032] (6) When the pelleting mold for the feed to be cleaned is a ring mold, the two support rollers can jointly support the ring mold and drive the ring mold to rotate around its own central axis when rotating in the same direction, so that the die holes distributed along the circumferential direction on the ring mold pass through the axial energy position of the die holes one after another; by driving the two support rollers simultaneously through the same chain, it is beneficial to maintain the coordination of the movement of the two support rollers and make the transmission structure more compact.

[0033] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice. Attached Figure Description

[0034] Figure 1 This is a three-dimensional view of an embodiment of the ultrasonic cleaning machine for feed pelleting molds of the present invention.

[0035] Figure 2 for Figure 1 The image shows a top view of an ultrasonic cleaning machine for feed pelleting molds.

[0036] Figure 3 for Figure 2 The image shows a cross-sectional view along line AA of an ultrasonic cleaning machine for feed pelleting molds.

[0037] Figure 4 for Figure 1 The diagram shows the internal structure of an ultrasonic cleaner for feed pelleting molds.

[0038] The markings in the diagram are as follows: 1-cleaning tank, 2-heating component mounting base, 3-heating component, 4-roller mounting plate, 5-bearing, 6-support roller, 7-roller mounting base, 8-ring mold, 9-chain, 10-gear motor, 11-inlet, 12-drive sprocket, 13-outlet, 14-driven sprocket, 15-ultrasonic vibrator. Detailed Implementation

[0039] The present invention will now be clearly and completely described in conjunction with the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly noted that:

[0040] The technical solutions and features provided in the various sections, including the following description, can be combined with each other without conflict. Furthermore, where possible, these technical solutions, features, and related combinations can be given specific technical subject matter and protected by relevant patents.

[0041] The embodiments of the present invention described below are generally only some embodiments and not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of patent protection.

[0042] The terms “comprising,” “having,” and any variations thereof in this specification, the corresponding claims, and the relevant portions are intended to cover non-exclusive inclusion.

[0043] The feed pelleting die referred to in this specification includes a ring die 8 and a flat die. The axial direction of the die hole refers to the direction extending along the depth of the die hole; extending outward from the center of the hole along the axial direction means extending from the inside of the die hole through the hole to the outside of the feed pelleting die. For the ring die 8, the axial direction of the die hole usually extends radially along the ring die 8; for the flat die, the axial direction of the die hole is usually perpendicular to the surface of the flat die.

[0044] The ultrasonic radiating surface, as referred to in this specification, is the working surface of the ultrasonic generating assembly that contacts the cleaning fluid and transmits ultrasonic vibrations to it. The ultrasonic radiating surface can be formed directly from the working surface of the ultrasonic transducer, or it can be formed from the surface of a vibration transmission component coupled to the ultrasonic transducer facing the cleaning fluid. The ultrasonic action zone refers to the area in the cleaning fluid that can peel off feed residue within the mold orifice under the action of ultrasonic vibration. The ultrasonic action zone can be determined based on the number and arrangement of the ultrasonic transducers, the output frequency, the output power, the cleaning fluid level, and the tank structure, and does not require a visible or absolutely fixed boundary.

[0045] The die support position is the spatial location of the feed pelleting die after the die support assembly supports it. The axial energy-receiving position of the die hole is the location or area where the die hole receives ultrasonic action, determined by the relative position of the die support position and the ultrasonic radiation surface; it does not necessarily have to be a single geometric point. When the die hole is located in the axial energy-receiving position, the opening of the die hole facing the ultrasonic radiation surface is located within the ultrasonic action area, and the ultrasonic radiation surface is located on the side extending outward from the opening along the axial direction of the die hole, allowing the ultrasonic action to act on the interior of the die hole through the opening.

[0046] like Figures 1 to 4As shown, this embodiment provides an ultrasonic cleaning machine for cleaning a feed pelleting die 8. The ultrasonic cleaning machine for feed pelleting dies includes a cleaning tank 1, a die support assembly, an ultrasonic generating assembly, a relative motion driving assembly, and a heating assembly. Figure 1 The overall structure of the feed pelleting die ultrasonic cleaner after the ring die 8 is installed is shown; Figure 2 The relative arrangement of the mold support assembly, heating assembly, and ring mold 8 within the cleaning tank 1 is shown; Figure 3 The chain drive structure of the relative motion drive assembly and the position of the ultrasonic transducer 15 relative to the ring mold 8 are shown. Figure 4 The arrangement of the support roller 6, heating element 3, ultrasonic transducer 15, and relative motion drive assembly is shown after removing part of the structure of the ring mold 8 and the cleaning tank 1.

[0047] The top of the cleaning tank 1 is open to allow the ring mold 8 to be placed into or removed from the cleaning tank 1 by hoisting or other handling methods. The cleaning tank 1 is used to hold the cleaning fluid, and its shape and volume are determined according to the outer diameter, width, and required liquid level of the ring mold 8 to be cleaned. The cleaning fluid can be water or an aqueous solution containing cleaning aids; in this embodiment, water is preferred to reduce residual chemical cleaning agents after cleaning.

[0048] The cleaning tank 1 has an inlet 11 and an outlet 13 on opposite sides. The inlet 11 is used to add cleaning solution into the cleaning tank 1, and the outlet 13 is located near the bottom of the cleaning tank 1 to discharge the cleaning solution and any feed residue discharged with it after cleaning. Both the inlet 11 and outlet 13 are equipped with control valves. These control valves can be manual or electrically controlled. During cleaning, the control valve at outlet 13 is closed to maintain the cleaning solution at a set level in the cleaning tank 1; after cleaning, the control valve at outlet 13 is opened to allow the cleaning solution to drain from the bottom of the cleaning tank 1.

[0049] The mold support assembly is installed inside the cleaning tank 1 and includes two spaced-apart support rollers 6 (each support roller 6 can be divided into one or more independent segments). The axes of the two support rollers 6 are parallel to each other. Each support roller 6 is supported at both ends by bearings 5 ​​on oppositely arranged roller fixing plates 4. The roller fixing plates 4 are mounted on roller fixing seats 7, which are fixed to the bottom of the cleaning tank 1 or to a supporting frame within the cleaning tank 1. Thus, the two support rollers 6 can rotate around their respective axes.

[0050] The ring mold 8 is placed between two support rollers 6, which are located on either side below the ring mold 8 and jointly support it. The axes of both support rollers 6 are parallel to the central axis of the ring mold 8, and their outer circumferential surfaces contact the outer circumferential surface of the ring mold 8. The axial distance, diameter, and installation height of the two support rollers 6 together define the mold support position of the ring mold 8. The length of the support rollers 6 can be adapted to the width of the ring mold 8, allowing the ring mold 8 to be stably supported on the two support rollers 6.

[0051] After adding cleaning fluid to the cleaning tank 1, at least the area with the die holes at the bottom of the ring die 8 should be immersed in the cleaning fluid. The level of the cleaning fluid can be lower than the top of the ring die 8, so that the ring die 8 is partially immersed in the cleaning fluid, or it can be higher than the top of the ring die 8, so that the ring die 8 is completely immersed in the cleaning fluid. When the ring die 8 is partially immersed in the cleaning fluid, as the ring die 8 rotates around its central axis, the die holes at different circumferential positions on the ring die 8 can sequentially enter the cleaning fluid.

[0052] The relative motion drive assembly includes a geared motor 10, a drive sprocket 12, two driven sprockets 14, and a chain 9. The geared motor 10 is mounted on a mounting bracket inside the cleaning tank 1 or on a supporting structure above the cleaning tank 1. The drive sprocket 12 is connected to the output shaft of the geared motor 10 and is located above the two driven sprockets 14. The two driven sprockets 14 are coaxially connected to one end of two support rollers 6 on the same side. The chain 9 is wound around the drive sprocket 12 and the two driven sprockets 14.

[0053] When the geared motor 10 is running, the driving sprocket 12 simultaneously drives two driven sprockets 14 to rotate via the chain 9. The two driven sprockets 14 then drive two support rollers 6 to rotate in the same direction. The two support rollers 6, through contact with the outer circumferential surface of the ring die 8, drive the ring die 8 to rotate around its own central axis. The geared motor 10 can be an adjustable-speed geared motor to adjust the rotation speed of the ring die 8 according to its diameter, number of die holes, degree of blockage, and ultrasonic intensity. Preferably, the ring die 8 rotates at a low speed that allows each die hole to remain in the axially charged position for a sufficient time; however, the specific rotation speed does not constitute a limitation of the invention.

[0054] In another specific embodiment, the relative motion drive assembly can be connected to only one of the support rollers 6, which drives the ring mold 8 to rotate, while the other support roller 6 acts as a driven support roller and rotates with the ring mold 8. The illustrated embodiment uses the same chain 9 to drive both support rollers 6 simultaneously, which is beneficial for maintaining coordinated movement between the two support rollers 6.

[0055] The ultrasonic generating assembly includes an ultrasonic generator and multiple ultrasonic transducers 15. The ultrasonic generator can be housed in an electrical box outside the cleaning tank 1 and electrically connected to the multiple ultrasonic transducers 15 via waterproof cables. The ultrasonic transducers 15 can be piezoelectric ultrasonic transducers or other ultrasonic transducers capable of converting electrical drive signals into mechanical vibrations.

[0056] like Figure 3 and Figure 4 As shown, multiple ultrasonic transducers 15 are spaced apart between two support rollers 6 and located below the mold support position of the ring mold 8. The multiple ultrasonic transducers 15 can be arranged in multiple rows and columns along the central axis of the ring mold 8 and perpendicular to the central axis of the ring mold 8, so that the ultrasonic action covers multiple mold hole arrangement areas in the width direction of the ring mold 8. The specific number and spacing of the ultrasonic transducers 15 are determined according to the width of the ring mold 8, the output power of the ultrasonic transducers 15, and the required range of the ultrasonic action area.

[0057] In the illustrated embodiment, the ultrasonic transducer 15 adopts a waterproof structure that isolates and seals it from the cleaning fluid. Multiple ultrasonic transducers 15, facing the working surface of the ring mold 8, contact the cleaning fluid and collectively form an ultrasonic radiation surface. The working surfaces of the multiple ultrasonic transducers 15 can be located in the same plane, making the ultrasonic radiation surface planar overall. The mechanical vibration generated by the ultrasonic transducer 15 is transmitted to the cleaning fluid through the ultrasonic radiation surface, thereby forming an ultrasonic action zone above the ultrasonic radiation surface.

[0058] In another embodiment not shown, multiple ultrasonic transducers 15 can be fixed to the side of the ultrasonic radiation plate belonging to the ultrasonic generating assembly that faces away from the cleaning fluid. The multiple ultrasonic transducers 15 are coupled to the ultrasonic radiation plate, and an ultrasonic radiation surface is formed by the ultrasonic radiation plate facing the surface of the cleaning fluid. The ultrasonic transducers 15 and the ultrasonic radiation plate can be connected by adhesive, threaded connection, welding, or compression, as long as the ultrasonic vibration generated by the ultrasonic transducer 15 can be transmitted to the cleaning fluid through the ultrasonic radiation plate.

[0059] When the ring die 8 is in the die support position, the area at the bottom of the ring die 8 corresponding to the ultrasonic radiation surface forms the axial energy-receiving position of the die hole. The die hole of the ring die 8 penetrates the wall of the ring die 8 radially. For the die hole located in the lower center of the ring die 8, the orifice facing the ultrasonic radiation surface is an orifice provided on the outer circumferential surface of the ring die 8. This orifice is opposite to the ultrasonic radiation surface and located within the ultrasonic action zone. A ray extending downward from the center of this orifice along the axial direction of the die hole extends outward from the ring die 8 and intersects with the ultrasonic radiation surface. As a result, ultrasonic vibration generates cavitation and liquid disturbance in the cleaning fluid on the side where the orifice is located, and acts on the interior of the die hole through the orifice.

[0060] When the ultrasonic radiating surface is planar, the vertical distance from the center of the orifice at the axial energy-receiving position of the die hole to the ultrasonic radiating surface is set to 10mm to 40mm. This vertical distance can be determined by selecting the diameter of the support roller 6, adjusting the height of the roller fixing seat 7, or adjusting the installation height of the ultrasonic transducer 15. Setting the vertical distance within the above range allows for maintaining a movement gap between the ring die 8 and the ultrasonic generating assembly, and ensures that the orifice is located within the ultrasonic action zone above the ultrasonic radiating surface. In one specific embodiment, the vertical distance can be selected within the range of 10mm to 40mm based on the diameter of the ring die 8 and the depth of the die hole, and the corresponding installation position can be determined through a cleaning test.

[0061] In another optional embodiment, the ultrasonic radiating surface is generally an arc surface adapted to the outer peripheral surface of the ring mold 8. The arc surface extends along the central axis of the ring mold 8 and is arc-shaped in a section perpendicular to the central axis of the ring mold 8; the side of the arc surface facing the ring mold 8 is concave, and the central axis of curvature of the arc surface coincides with or is adjacent to the central axis of the ring mold 8. Multiple ultrasonic transducers 15 are arranged at intervals along the circumference and / or axial direction of the ring mold 8. The working surfaces of the multiple ultrasonic transducers 15 can be connected to form a continuous arc surface, or they can form an ultrasonic radiating surface that is approximately arc-shaped as a whole, composed of multiple segmented radiating surfaces. A gap is left between the ultrasonic radiating surface and the outer peripheral surface of the ring mold 8 for the cleaning fluid to enter and flow, so that the orifices of multiple mold holes located within the circumferential range corresponding to the arc surface are respectively opposite to the ultrasonic radiating surface, and the rays extending outward from the center of each orifice along the axial direction of the corresponding mold hole intersect the ultrasonic radiating surface. For a die hole located at the axial energy-receiving position, the distance between the center of the hole opening and the intersection of the corresponding ray and the ultrasonic radiation surface can be 10mm to 40mm. This allows the ultrasonic force to act on the interior of the die hole along its axial direction through the opening of each die hole.

[0062] Planar and curved ultrasonic radiating surfaces differ in structural applicability and ultrasonic range. With a planar design, multiple ultrasonic transducers 15 can be arranged according to a unified mounting reference, facilitating the processing, installation, sealing, and maintenance of the ultrasonic generating components. Furthermore, it has a lower dependence on the outer diameter of the ring mold 8, allowing for adaptation to ring molds 8 with different outer diameters by adjusting the mold support position, and also facilitating its use as a flat mold. Since the outer circumferential surface of the ring mold 8 is cylindrical, the distance from the orifices at different circumferential positions on the outer circumferential surface of the ring mold 8 to the planar ultrasonic radiating surface, as well as the relative angle between the corresponding mold hole axis and the ultrasonic radiating surface, varies with the circumferential position. Therefore, the axial energy-receiving position of the mold hole is relatively concentrated in the region of the ring mold 8 adjacent to the ultrasonic radiating surface. By driving the ring mold 8 to rotate, the mold holes at different circumferential positions can sequentially pass through this region. When an arc-shaped surface is adopted to match the outer circumferential surface of the ring die 8, the distance between the ultrasonic radiating surface and the outer circumferential surface of the ring die 8 can remain basically consistent over a large circumferential range. Furthermore, the relative relationship between the arc surface and the corresponding die hole axis can remain relatively consistent, thereby expanding the circumferential range covered by the axial energy-receiving position of the die hole. This allows more die holes to be simultaneously within the ultrasonic action zone and improves the uniformity of ultrasonic action on different die holes. The arc-shaped surface requires determining the corresponding radius of curvature based on the outer diameter of the ring die 8, making its processing and sealing structure relatively complex. When adapting to ring dies 8 with different outer diameters, ultrasonic generating components with different radii of curvature can be used, or an installation structure that can adjust the position of the arc surface and its distance from the ring die 8 can be set. Therefore, either a planar or arc-shaped ultrasonic radiating surface can be selected based on the type and size range of the feed pelleting die to be cleaned, the equipment versatility requirements, and the required ultrasonic action range.

[0063] As the two support rollers 6 drive the ring mold 8 to rotate, the die holes originally located in other circumferential positions on the ring mold 8 rotate sequentially to the lower part of the ring mold 8 and pass through the axially charged position of the die hole one after another. Thus, the die holes in different circumferential positions can sequentially align their openings with the ultrasonic radiation surface, rather than remaining permanently fixed in the same strong or weak action area in the cleaning fluid. For multiple rows of die holes arranged along the central axis of the ring mold 8, multiple ultrasonic transducers 15 are arranged at intervals along corresponding directions, ensuring that all these die holes are subjected to ultrasonic action when passing through the axially charged position of the die hole.

[0064] The ultrasonic generator drives the ultrasonic transducer 15 with a periodically varying output frequency to form a swept frequency output. The swept frequency output has a lower sweep frequency and an upper sweep frequency, both located within the range of 20kHz to 40kHz, and the difference between the upper and lower sweep frequencies is 2kHz to 6kHz. It should be noted that the aforementioned 20kHz to 40kHz is a frequency range used to select the lower and upper sweep frequencies, and it is not required that each sweep cycle varies from 20kHz to 40kHz.

[0065] In one specific embodiment, the lower limit frequency of the sweep frequency is 23kHz, the upper limit frequency is 27kHz, and the output frequency periodically varies between 23kHz and 27kHz with 25kHz as the center. The difference between the upper and lower limits of the sweep frequency is 4kHz. The output frequency can vary back and forth between the lower and upper limits of the sweep frequency in a triangular wave, sawtooth wave, sine wave, or step pattern. When the output frequency changes periodically, the areas of strong and weak ultrasonic action formed by reflection and superposition in the cleaning fluid change accordingly, which helps to reduce the relatively fixed weak action areas.

[0066] The ultrasonic generator can also output drive power to the ultrasonic transducer 15 in an intermittent pulse pattern. The intermittent pulse pattern includes periodically alternating ultrasonic output periods and intermittent periods. During the ultrasonic output period, the ultrasonic generator drives the ultrasonic transducer 15 at a set drive power; during the intermittent period, the ultrasonic generator stops outputting drive power to the ultrasonic transducer 15, or drives the ultrasonic transducer 15 at a lower drive power than during the ultrasonic output period. The duration of the ultrasonic output period and the intermittent period can be set according to the mold hole depth, the degree of consolidation of feed residue, and the output capacity of the ultrasonic transducer 15.

[0067] Sweep frequency output and intermittent pulse mode can be implemented simultaneously. For example, during each ultrasonic output period, the output frequency is periodically varied between the lower and upper sweep frequencies; upon entering the intermittent period, the output drive power is stopped or reduced; and the sweep frequency output is resumed in the next ultrasonic output period. The sweep frequency cycle and the intermittent pulse cycle can be independent of each other or synchronously controlled according to a preset timing sequence. The intermittent period facilitates the exchange of cleaning fluid within the mold orifice and further collapses the cavitation bubbles formed during the ultrasonic output period. The resulting localized liquid disturbance can act on the softened feed residue.

[0068] Regarding frequency sweep output, when the boundary conditions of the cleaning tank 1, cleaning fluid, ultrasonic radiation surface, and ring mold 8 are relatively fixed, ultrasonic vibration at a fixed frequency is prone to forming relatively fixed strong and weak action regions due to sound wave reflection and superposition. Periodically changing the output frequency within the allowable operating frequency range of the ultrasonic transducer 15 can alter the wavelength of the ultrasonic waves in the cleaning fluid and the phase superposition relationship during propagation, causing the position and intensity of the strong and weak action regions to change with the output frequency. Therefore, when the die hole on the ring mold 8 passes through the ultrasonic action region, the opening and different positions within the die hole can be subjected to ultrasonic action at different frequencies sequentially, reducing the likelihood of a single weak action region continuously remaining in the same position. Simultaneously, when the temperature, level, and load state of the cleaning fluid and the pelleting mold of the feed to be cleaned change, the actual operating state of the ultrasonic generating component may also change. Frequency sweep output can increase the chance of the output frequency passing through a suitable operating frequency, allowing the ultrasonic generating component to maintain a relatively stable ultrasonic action under changing load conditions.

[0069] Regarding the output frequency, the 20kHz–40kHz range used in this embodiment is relatively low compared to higher ultrasonic cleaning frequencies. Within this frequency range, cavitation bubbles typically have sufficient growth time, and their collapse generates strong local pressure changes, microjets, and liquid disturbances, making it suitable for acting on compacted or solidified feed residues formed under pressure within the mold cavity. The relatively low-frequency ultrasonic vibration also reduces the rapid attenuation of ultrasonic energy during propagation, facilitating the entry of ultrasonic action into deeper mold cavities through the orifice facing the ultrasonic radiation surface. Limiting both the lower and upper sweep frequencies to the 20kHz–40kHz range balances the ability to peel off solidified feed residues, the propagation capability of ultrasonic vibration within the cleaning fluid and mold cavity, and the operational stability of the ultrasonic transducer 15. Setting the difference between the upper and lower sweep frequencies to 2kHz–6kHz allows for changes in the intensity range of ultrasonic action while preventing the output frequency from deviating excessively from the appropriate operating frequency of the corresponding ultrasonic transducer 15.

[0070] In the intermittent pulse mode, cavitation bubbles continuously forming during the ultrasonic output period may gradually aggregate into bubble clusters. These bubble clusters can scatter or shield the subsequent propagation of ultrasonic energy into the mold cavity. Setting intermittent periods allows the bubble clusters to dissipate, enabling the cleaning fluid to re-enter the mold cavity and the gaps formed after feed residue detachment. Furthermore, the detached or loosened feed residue is removed from its original attachment position under the combined effects of gravity, liquid turbulence, and the movement of the ring mold 8. At the start of the next ultrasonic output period, the ultrasonic action can again act on the interface between the renewed cleaning fluid and residue, thus creating repeated cavitation impacts and liquid exchange processes. The intermittent pulse mode also reduces the rapid temperature rise of the cleaning fluid caused by continuous output and the prolonged high-load condition of the ultrasonic transducer 15. Using a lower drive power during the intermittent periods than during the ultrasonic output periods can reduce cavitation intensity while maintaining a certain degree of liquid turbulence.

[0071] When swept frequency output, relatively low-frequency output, and intermittent pulse mode are combined, these three factors influence the cleaning of the mold orifice from the spatial distribution of ultrasonic action, the intensity of cavitation, and the temporal process of ultrasonic action, respectively. During each ultrasonic output period, the output frequency is periodically varied between the selected lower and upper sweep frequencies within the range of 20kHz to 40kHz. This utilizes the cavitation effect generated by the relatively low-frequency ultrasound to impact and peel off solidified feed residues, and the intensity of the ultrasonic action varies with frequency. During subsequent intermittent periods, output is stopped or the output power is reduced, providing time for the bubble clusters to dissipate, for the cleaning fluid to replenish the mold orifice, and for the detached residues to be discharged. Through the periodic alternation of multiple ultrasonic output periods and intermittent periods, the feed residues within the mold orifice repeatedly undergo cavitation at different frequencies and the exchange of cleaning fluid. Simultaneously, the ring mold 8 continuously rotates relative to the ultrasonic radiation surface, causing mold orifices at different positions to pass sequentially through the axial energy-receiving positions of the mold orifice. This creates a coordination between the temporally varying ultrasonic action and the spatial movement of the ring mold 8, which helps improve the uniformity of the ultrasonic action received by mold orifices at different positions and depths.

[0072] Furthermore, the rotation of the ring mold 8 can be used to allow the same mold hole to sequentially pass through areas with different ultrasonic action parameters, thereby forming a staged cleaning process. Specifically, multiple ultrasonic transducers 15 can be sequentially divided into at least a first transducer group and a second transducer group along the direction in which the mold hole passes through the ultrasonic radiation surface when the ring mold 8 rotates, and a third transducer group can also be further provided. Each transducer group forms a corresponding sub-action area in the cleaning fluid, and each of the sub-action areas is sequentially distributed along the direction of movement of the mold hole on the ring mold 8 relative to the ultrasonic radiation surface, and together constitutes the ultrasonic action area. When the ultrasonic radiation surface is a plane, each transducer group can be sequentially arranged along the tangential direction of the outer circumference of the ring mold 8 through the plane; when the ultrasonic radiation surface is an arc surface adapted to the outer circumference of the ring mold 8, each transducer group can be sequentially arranged along the circumferential extension direction of the arc surface. Each transducer group may include multiple ultrasonic transducers 15 spaced apart along the central axis of the ring mold 8, so that the corresponding sub-action area covers multiple rows of mold holes distributed along the central axis of the ring mold 8.

[0073] To control each transducer group separately, the ultrasonic generator may include at least two independently controllable drive channels, each drive channel being electrically connected to one transducer group. The drive signals output by different drive channels to their corresponding transducer groups may differ in at least one of the following: output frequency, lower sweep frequency, upper sweep frequency, sweep period, output drive power, duration of ultrasonic output periods, duration of intermittent periods, and output timing. Each transducer group may operate simultaneously according to its different drive parameters, or sequentially or alternately according to a preset timing sequence. When different transducer groups use significantly different output frequencies, each transducer group may use an ultrasonic transducer 15 adapted to its output frequency. The ultrasonic generator may be a multi-channel ultrasonic generator integrating multiple drive channels within the same device, or it may consist of multiple ultrasonic generation modules that each drive a corresponding transducer group.

[0074] In a phased cleaning method, the first transducer group, passing along the rotation direction of the ring mold 8, uses a relatively low lower and upper sweep frequency, and a relatively high output drive power or a high proportion of ultrasonic output time, to initially impact the compacted or solidified feed residue inside the mold orifice, causing the feed residue to loosen, crack, or partially peel off. The second transducer group, which then passes through, uses a different sweep frequency range, output drive power, or intermittent pulse period than the first transducer group to further peel off the loosened feed residue. When a third transducer group is included, it can use a relatively high output frequency or a relatively low proportion of ultrasonic output time to continue applying ultrasonic action to the fine deposits remaining on the orifice wall, and provide a longer interval for the cleaning fluid to enter the mold orifice and for the detached residue to exit. The parameter relationships of the above stages can be adjusted according to the orifice diameter, orifice depth, and the degree of solidification of the feed residue; it is not required that the output frequency or output drive power of each transducer group must increase or decrease progressively in a single direction.

[0075] During the continuous rotation of the ring mold 8, the same mold hole sequentially passes through the sub-areas corresponding to the first, second, and third transducer groups, thereby receiving ultrasonic treatment under different ultrasonic parameters. After one revolution of the ring mold 8, the same mold hole can pass through each of the sub-areas again in the same order, thus repeating the staged cleaning process. The distance between each transducer group along the movement path of the ring mold 8 and the rotation speed of the ring mold 8 together determine the time taken for the same mold hole to move from one sub-area to the next. The control component can control the driving speed of the relative motion drive component according to the distance between each transducer group, and can coordinate the output timing of the ultrasonic generator with the rotation speed of the ring mold 8, so that the same mold hole receives corresponding ultrasonic treatment when passing through different sub-areas.

[0076] With the above settings, the spatial parameter differences along the motion path of the ring mold 8 can be transformed into the time sequence experienced by the same mold hole as the ring mold 8 rotates. This allows each mold hole on the ring mold 8 to sequentially undergo different ultrasonic cleaning stages without requiring separate position alignment or individual control. This staged cleaning method can be used for both planar ultrasonic radiating surfaces and arc-shaped ultrasonic radiating surfaces that are adapted to the outer circumference of the ring mold 8.

[0077] The following is combined Figure 4 The arrangement of the ultrasonic transducers 15 shown illustrates a specific implementation method for staged ultrasonic cleaning.

[0078] like Figure 4As shown, this embodiment includes sixteen ultrasonic transducers 15 arranged in a 4×4 matrix. All sixteen transducers 15 face the working surface of the ring mold 8 and lie in the same plane to form a planar ultrasonic radiation surface. The direction of movement of the outer circumference of the ring mold 8 above the ultrasonic radiation surface during rotation is defined as the direction in which the mold holes pass through the ultrasonic action zone. Along this direction, the sixteen ultrasonic transducers 15 are sequentially divided into a first transducer group, a second transducer group, a third transducer group, and a fourth transducer group. Each transducer group includes four ultrasonic transducers 15 spaced apart along the central axis of the ring mold 8. Thus, the sub-action zone formed by each transducer group covers multiple rows of mold holes on the ring mold 8 along the central axis of the ring mold 8, and the sub-action zones formed by the four transducer groups are sequentially distributed along the rotation direction of the ring mold 8.

[0079] In this embodiment, the outer diameter of the ring mold 8 is 600 mm, and the width of the ring mold 8 along its central axis is 200 mm. The working surface of each ultrasonic transducer 15 is a circular plane with a diameter of 50 mm. The center distance between adjacent ultrasonic transducers 15 is 60 mm, so that the coverage dimension of the 4×4 matrix along the rotation direction of the ring mold 8 and along the central axis direction of the ring mold 8 is 230 mm. The vertical projection of the central axis of the ring mold 8 onto the ultrasonic radiation surface is located between the second transducer group and the third transducer group. The center positions of the first transducer group, the second transducer group, the third transducer group, and the fourth transducer group are -90 mm, -30 mm, 30 mm, and 90 mm respectively relative to this vertical projection along the rotation direction of the ring mold 8. The vertical distance between the outer peripheral surface of the ring mold 8 closest to the ultrasonic radiation surface and the ultrasonic radiation surface is set to 20 mm. Based on a radius of 300mm for the ring mold 8, the vertical distance from the outer circumferential surface of the ring mold 8 corresponding to the second and third oscillator groups to the ultrasonic radiation surface is approximately 21.5mm; the vertical distance from the outer circumferential surface of the ring mold 8 corresponding to the first and fourth oscillator groups to the ultrasonic radiation surface is approximately 33.8mm.

[0080] Therefore, the vertical distance from the center of the opening of the mold hole corresponding to the four transducer groups to the ultrasonic radiation surface is all within the range of 10mm to 40mm. The working surface size and arrangement of the ultrasonic transducer 15 also allow the rays extending outward from the center of the corresponding opening along the axial direction of the mold hole to intersect with the working surface of the corresponding transducer group, thereby enabling the four transducer groups to form corresponding axial energy-receiving positions of the mold hole.

[0081] This embodiment employs an ultrasonic generator with four independent drive channels, each drive channel being electrically connected to four ultrasonic transducers 15 in a transducer group. Each ultrasonic transducer 15 has a rated drive power of 100W, and each drive channel has a maximum output power of 400W, resulting in a total rated output power of 1600W for the ultrasonic generator. The designed operating frequency of the ultrasonic transducers 15 in the first and second transducer groups is 25kHz, in the third transducer group it is 31kHz, and in the fourth transducer group it is 37kHz. The effective operating frequency range of the ultrasonic transducers 15 in each transducer group covers the corresponding lower sweep frequency to the upper sweep frequency. Each drive channel is equipped with an impedance matching circuit adapted to the corresponding transducer group to ensure stable operation of the corresponding transducer group within the set sweep frequency range. The drive parameters for each transducer group are set according to Table 1.

[0082] Table 1

[0083] The difference between the upper and lower sweep frequencies of each transducer group is 4 kHz, and both the lower and upper sweep frequencies are within the range of 20 kHz to 40 kHz. During each ultrasonic output period, each drive channel causes the output frequency to oscillate between the corresponding lower and upper sweep frequencies in a triangular wave pattern. During each interval, the corresponding drive channel stops outputting drive power to the ultrasonic transducer 15. The intermittent pulse period of each transducer group is 1.2 s, and they operate periodically according to the corresponding ultrasonic output and interval periods.

[0084] The first transducer group employs a relatively low-frequency sweep output of 23kHz–27kHz, utilizing 70% of its rated output power and accounting for approximately 66.7% of the ultrasonic output time. Its function is to initially impact the compacted or solidified feed residue within the orifice through cavitation caused by the relatively low-frequency ultrasound after the orifice enters the ultrasonic action zone, allowing the cleaning fluid to gradually penetrate the gap between the feed residue and the orifice wall. By not directly using maximum output power, the first transducer group reduces the shielding effect caused by the rapid formation of dense air bubbles near the orifice opening when the orifice first enters the ultrasonic action zone, which would otherwise obstruct the continued entry of ultrasonic energy into the orifice.

[0085] The second transducer group continues to use a sweep frequency range of 23kHz to 27kHz, but increases the output drive power to the rated output power of each ultrasonic transducer 15, and increases the proportion of ultrasonic output time to approximately 83.3%. When the mold orifice enters the sub-action zone corresponding to the second transducer group after passing through the first transducer group, the feed residue has already been subjected to initial impact and has been wetted to a certain extent. The second transducer group, using higher output drive power and a longer ultrasonic output time, further impacts and peels off the feed residue that has already become loose or cracked. The second transducer group thus constitutes the transducer group that performs the main removal function of feed residue in the mold orifice.

[0086] The third transducer group employs a sweep frequency range of 29kHz to 33kHz. Its output frequency is higher than that of the first and second transducer groups, thereby altering the wavelength and sound field distribution of the ultrasound waves within the cleaning fluid and the die orifice. This allows residues that were previously in a relatively weak position under the influence of the first two transducer groups to be subjected to ultrasonic action at different frequencies. The third transducer group uses 15 ultrasonic transducers with an output drive power of 80W each and accounts for approximately 58.3% of the ultrasonic output time. This is used to further peel away the broken but still attached feed residues from the die orifice wall, and the relatively extended intervals promote the entry of the cleaning fluid into the space created after the feed residues have detached.

[0087] The fourth transducer group employs a frequency sweep range of 35kHz to 39kHz, with each ultrasonic transducer generating 15 transducers with an output drive power of 60W and accounting for approximately 33.3% of the ultrasonic output time. Compared to the first three transducer groups, the fourth transducer group creates a more concentrated cavitation effect with relatively milder individual cavitation impacts, suitable for continuing to act on fine deposits on the pore walls. The interval between ultrasonic outputs in the fourth transducer group is longer than its ultrasonic output time, providing sufficient time for the bubble clusters to dissipate, for the cleaning fluid to enter the mold orifice, and for the detached feed residue to exit the mold orifice. Therefore, the fourth transducer group is mainly used for subsequent fine cleaning and promoting residue removal.

[0088] In this embodiment, the ring mold 8 rotates continuously at a speed of 0.5 r / min, and the mold holes on the outer circumference of the ring mold 8 pass through the ultrasonic action zone in the order of the first transducer group, the second transducer group, the third transducer group, and the fourth transducer group. For a ring mold 8 with an outer diameter of 600 mm, the linear velocity of its outer circumference is approximately 15.7 mm / s. The working surface size of each ultrasonic transducer 15 along the rotation direction of the ring mold 8 is 50 mm, so the time for the same mold hole to pass through the sub-action zone corresponding to each transducer group is approximately 3.2 s. During this time, the same mold hole can experience at least two complete intermittent pulse cycles. The total coverage size of the four transducer groups along the rotation direction of the ring mold 8 is 230 mm, and the time for the same mold hole to pass through the entire ultrasonic action zone once is approximately 14.6 s.

[0089] The cleaning fluid is water, heated to 55°C and maintained at around 55°C by heating element 3. Once the cleaning fluid reaches the set temperature, the control unit simultaneously activates the geared motor 10 and the ultrasonic generator, causing the ring mold 8 to rotate continuously and the four transducer groups to operate according to the aforementioned drive parameters. One cleaning process lasts 30 minutes, during which the ring mold 8 rotates approximately 15 times, allowing each mold hole on the ring mold 8 to undergo approximately 15 stages of ultrasonic action from the first to the fourth transducer groups.

[0090] The above parameter settings ensure that the same mold hole undergoes a series of processes during a single passage through the ultrasonic action zone: a relatively low-power low-frequency pretreatment, a higher-power low-frequency enhanced ablation, further cleaning at an intermediate frequency, and fine cleaning and fluid exchange at a higher frequency. The continuous rotation of the ring mold 8 translates the spatial parameter differences between the four transducer groups into a temporal sequence experienced by the same mold hole, eliminating the need for individual position identification and control of a large number of mold holes. The ring mold rotation speed of 0.5 r / min, coupled with an intermittent pulse period of 1.2 s, allows the mold hole to receive multiple ultrasonic outputs as it passes through each transducer group, while preventing the mold hole from remaining in a single sub-action zone for too long.

[0091] It should be noted that the dimensions of the ring mold 8, the dimensions of the ultrasonic transducers 15, the spacing between them, the output frequency, the output drive power, the intermittent pulse period, the ring mold rotation speed, and the cleaning time mentioned above are used to illustrate the coordination relationship between various parameters under a 4×4 planar array and do not constitute a limitation. For ring molds 8 with different outer diameters, different mold hole depths, or different degrees of blockage, the center distance of the ultrasonic transducers 15, the distance from the mold hole opening to the ultrasonic radiation surface, the drive parameters of each transducer group, and the rotation speed of the ring mold 8 can be adjusted accordingly. When the rotation direction of the ring mold 8 changes, the control component can also configure the drive parameters of the first to fourth transducer groups in reverse order, so that the same mold hole still passes through each sub-area in the order of pretreatment, enhanced peeling, further removal, and fine cleaning.

[0092] like Figure 2 and Figure 4 As shown, the heating assembly includes at least two heating elements 3, which are arranged on both sides of the mold support position of the ring mold 8. In the illustrated embodiment, the heating assembly includes four U-shaped heating elements 3, with two heating elements 3 respectively arranged on both sides of the mold support position of the ring mold 8. Each heating element 3 is fixed to the cleaning tank 1 by a heating element fixing seat 2. The heating part of the heating element 3 is immersed in the cleaning liquid and is spaced apart from the ring mold 8 and the support roller 6.

[0093] The heating element 3 can be a quartz heating rod. The surface of the quartz heating rod is relatively smooth, making it easy to clean feed residue adhering to the surface of the heating element 3. In other embodiments, the heating element 3 can also be a metal electric heating tube with a waterproof structure or other heating element capable of heating the cleaning fluid. Regardless of the specific form, at least two heating elements 3 are arranged on both sides of the mold support position to heat the cleaning fluid from different positions.

[0094] The ultrasonic cleaning machine for feed pelleting molds also includes a temperature sensing element and a control assembly. The temperature sensing element is located inside the cleaning tank 1 and is in contact with the cleaning fluid to detect the temperature of the cleaning fluid. The temperature sensing element can be a thermocouple, a resistance temperature detector (RTD), or other liquid temperature sensors. Preferably, the temperature sensing element is kept at a certain distance from the heating element 3 and the ultrasonic transducer 15 to reduce the influence of local heat sources or local vibrations on the detection results.

[0095] The control component is electrically connected to the temperature sensor, heating component, relative motion drive component, and ultrasonic generator. The control component can be a programmable logic controller (PLC), an industrial controller, or a control circuit consisting of a temperature controller and relays. The control component receives the temperature signal output from the temperature sensor and controls the heating element 3 to be energized or de-energized according to the detected temperature, maintaining the temperature of the cleaning fluid within a preset range.

[0096] The preset temperature range can be 20℃~80℃, preferably 30℃~70℃, and more preferably 50℃~60℃. In one specific embodiment, the cleaning fluid is water, and the control component maintains the water temperature at 50℃~60℃. Water within this temperature range can wet and soften feed residues containing starch and oil components inside the mold holes, allowing the feed residues to gradually detach from the hole walls under ultrasonic action.

[0097] When the temperature sensor detects that the temperature of the cleaning fluid is within the preset temperature range, the control component controls the relative motion drive component to drive the ring mold 8 to move relative to the ultrasonic radiation surface, and controls the ultrasonic generator to output drive power to the ultrasonic transducer 15, so that the rotation process of the ring mold 8 and the ultrasonic action at least partially overlap in time. The simultaneous control or simultaneous implementation mentioned here means that the movement of the ring mold 8 relative to the ultrasonic radiation surface and the transmission of ultrasonic vibration from the ultrasonic transducer 15 to the cleaning fluid exist simultaneously during the cleaning stage, and it is not required that the geared motor 10 and the ultrasonic generator start at exactly the same time.

[0098] This embodiment also provides a method for ultrasonic cleaning of feed pelleting molds using the aforementioned ultrasonic cleaning machine. Before cleaning, the control valve at the outlet 13 is closed, and water is added to the cleaning tank 1 through the inlet 11. The ring mold 8 to be cleaned is hoisted into the cleaning tank 1 and supported on two support rollers 6, so that the outer circumferential surfaces of the two support rollers 6 are in contact with the outer circumferential surfaces of the ring mold 8. The order of adding water and supporting the ring mold 8 can be adjusted according to operating conditions, as long as at least a portion of the area with mold holes on the ring mold 8 is immersed in water before applying ultrasonic action.

[0099] After the ring mold 8 is placed, check the relative position of the lower orifice of the ring mold 8 and the ultrasonic radiation surface. Ensure that the orifice located at the axial energy-receiving position of the mold hole is aligned with the ultrasonic radiation surface, and maintain the vertical distance from the center of the orifice to the ultrasonic radiation surface between 10mm and 40mm. A ray extending downward from the center of the orifice along the mold hole axial direction intersects the ultrasonic radiation surface, placing the orifice within the ultrasonic action zone.

[0100] The control component controls the heating element 3 to heat the water. When the temperature sensor detects that the water temperature has entered the preset temperature range, the control component starts the geared motor 10 and controls the ultrasonic generator to output drive power to the ultrasonic transducer 15. The geared motor 10 drives the two support rollers 6 to rotate in the same direction through the drive sprocket 12, chain 9 and two driven sprockets 14. The two support rollers 6 drive the ring mold 8 to rotate around its own central axis. At the same time, the ultrasonic transducer 15 transmits ultrasonic vibrations to the water through the ultrasonic radiation surface, forming an ultrasonic action zone in the water.

[0101] As the ring mold 8 rotates, the mold holes at different circumferential positions on the ring mold 8 pass through the axial energy-receiving positions of the mold holes one after another. The mold holes that enter the axial energy-receiving positions have their orifices facing the ultrasonic radiation surface entering the ultrasonic action zone. The cavitation and liquid disturbance formed by the water under the action of ultrasonic vibration act on the interior of the mold holes through the orifices. The feed residues that have been wetted and softened by heated water gradually detach from the hole walls or the depth of the mold holes under the action of ultrasound and enter the water in the cleaning tank 1.

[0102] During the cleaning process, the ultrasonic generator can periodically vary the output frequency between 23kHz and 27kHz, and output drive power in a periodic alternation of ultrasonic output periods and intermittent periods. As the output frequency changes, the location of the areas of strong and weak ultrasonic action in the water changes; as the ultrasonic output periods and intermittent periods alternate, cavitation bubbles form and collapse, and the cleaning fluid is exchanged within the mold orifice. The ring mold 8 rotates continuously, causing different mold orifices to repeatedly or sequentially pass through the axial energy-receiving positions of the mold orifices until the set cleaning time is reached or the feed residue within the mold orifice reaches the predetermined removal state.

[0103] After cleaning is complete, the control unit stops the ultrasonic generator and the geared motor 10, and shuts off the heating element 3. The control valve at the water outlet 13 is opened to allow water and any feed residue that has detached from the mold holes to drain from the cleaning tank 1. If necessary, clean water can be added again through the water inlet 11 to rinse the ring mold 8, and then the ring mold 8 can be removed from the cleaning tank 1.

[0104] In another embodiment not shown, the feed pelleting mold to be cleaned is a flat mold. The mold support assembly includes a support platform and a positioning part disposed on the support platform. The support platform can be annular or frame-shaped, used to support the periphery of the flat mold to reduce obstruction of the die hole distribution area on the flat mold. The positioning part is used to restrict the movement of the flat mold relative to the support platform in a direction parallel to the surface of the flat mold. The positioning part can be a positioning shaft that mates with the center hole of the flat mold, a positioning block that mates with the periphery of the flat mold, or a positioning pin disposed on the support platform.

[0105] The relative motion drive assembly is connected to the support platform via a transmission connection. In one specific embodiment, the relative motion drive assembly drives the support platform to rotate about an axis perpendicular to the surface of the flat mold, causing the flat mold to rotate with the support platform. The ultrasonic radiation surface is located below the flat mold, and the ultrasonic action area covers the mold hole distribution area radially along the flat mold, so that the mold holes at different circumferential positions pass through the axial energy-receiving positions of the mold holes successively as the flat mold rotates.

[0106] In another specific embodiment, the relative motion drive assembly includes a linear drive mechanism and a guide mechanism. The linear drive mechanism drives the support table to reciprocate in a direction parallel to the surface of the flat mold plate. The linear drive mechanism can employ a motor and lead screw transmission structure, a gear and rack transmission structure, or a linear actuator. The flat mold reciprocates with the support table, causing the mold holes at different positions on the flat mold to pass through the ultrasonic action zone sequentially.

[0107] The die hole axis of the flat mold is typically perpendicular to the mold plate surface. When the die hole is in the energy-receiving position along its axial direction, the orifice on the lower surface of the flat mold facing the ultrasonic radiation surface is opposite to the ultrasonic radiation surface. This orifice is located within the ultrasonic action zone, and a ray extending axially from the center of the orifice downwards along the die hole intersects the ultrasonic radiation surface. When the ultrasonic radiation surface is planar, the vertical distance from the center of the orifice to the ultrasonic radiation surface can also be set to 10mm–40mm. The aforementioned sweep frequency output, intermittent pulse mode, heating assembly, temperature detection element, and control assembly can also be applied to the cleaning process of the flat mold.

[0108] The above embodiments use a ring die 8 and a flat die as examples to illustrate the ultrasonic cleaning machine and method for feed pelleting dies. Those skilled in the art can adapt the quantity and arrangement of the die support assembly, relative motion drive assembly, and ultrasonic transducers 15 according to the specific shape and die hole distribution of the feed pelleting die, as long as the die holes at different positions on the feed pelleting die pass sequentially through the axial energy-receiving position defined by the die support position and the ultrasonic radiation surface.

Claims

1. A feed pelleting die ultrasonic cleaning machine characterized by: include: A cleaning tank for holding cleaning fluid; A mold support assembly is disposed in the cleaning tank and defines the mold support position for supporting a feed pelleting mold with multiple mold holes to be cleaned, so that at least a portion of the feed pelleting mold with the mold holes is immersed in the cleaning liquid. An ultrasonic generating assembly includes an ultrasonic generator and at least one ultrasonic transducer electrically connected to the ultrasonic generator, and has an ultrasonic radiation surface in contact with the cleaning fluid; the ultrasonic transducer is coupled to the ultrasonic radiation surface for transmitting ultrasonic vibrations through the ultrasonic radiation surface to the cleaning fluid and forming an ultrasonic action zone. The mold support position and the ultrasonic radiation surface together define the axial energy-receiving position of the mold hole; when the mold hole of the feed pelleting mold is located at the axial energy-receiving position of the mold hole, the opening of the mold hole facing the ultrasonic radiation surface is opposite to the ultrasonic radiation surface, the distance between the opening and the ultrasonic radiation surface makes the opening located within the ultrasonic action zone, and the ray extending outward from the center of the opening along the axial direction of the mold hole intersects the ultrasonic radiation surface; A relative motion drive assembly is connected to the mold support assembly for driving the feed pelleting mold relative to the ultrasonic radiation surface during the process of the ultrasonic generating assembly applying ultrasonic action to the cleaning liquid, so that the die holes at different positions on the feed pelleting mold pass through the axial energy-receiving positions of the die holes one after another.

2. The feed pelleting die ultrasonic cleaning machine according to claim 1, characterized in that: The ultrasonic generator is used to drive the ultrasonic transducer with a periodically changing output frequency during the process of the relative motion drive assembly driving the feed pelleting mold to move relative to the ultrasonic radiation surface, so as to form a sweep frequency output and output drive power to the ultrasonic transducer in an intermittent pulse manner.

3. The feed pelleting die ultrasonic washer of claim 2, wherein: The frequency sweep output has a lower frequency sweep limit and an upper frequency sweep limit, both of which are within the range of 20kHz to 40kHz; the output frequency of the ultrasonic generator changes periodically between the lower frequency sweep limit and the upper frequency sweep limit, and the difference between the upper frequency sweep limit and the lower frequency sweep limit is 2kHz to 6kHz.

4. The feed pelleting die ultrasonic cleaning machine according to claim 2, characterized in that: The intermittent pulse mode includes periodically alternating ultrasonic output periods and intermittent periods; the ultrasonic generator stops outputting driving power to the ultrasonic transducer during the intermittent period, or outputs driving power to the ultrasonic transducer at a lower level than during the ultrasonic output period.

5. The feed pelleting die ultrasonic cleaning machine according to claim 1, characterized in that: The ultrasonic generating assembly includes a plurality of ultrasonic transducers, which are spaced apart below the mold support position and are used to transmit ultrasonic vibrations to the cleaning fluid through the ultrasonic radiation surface; the surfaces of the plurality of ultrasonic transducers facing the mold support position form the ultrasonic radiation surface.

6. The ultrasonic cleaning machine for feed pelleting molds according to claim 1, characterized in that: It also includes a heating assembly, which includes at least two heating elements disposed in the cleaning tank for heating the cleaning liquid; the at least two heating elements are arranged on both sides of the mold support position, and each heating element is fixed to the cleaning tank by a heating element fixing seat.

7. The ultrasonic cleaning machine for feed pelleting molds according to claim 6, characterized in that: It also includes a temperature detection element and a control component. The temperature detection element is used to detect the temperature of the cleaning fluid. The control component is electrically connected to the temperature detection element and the heating component, respectively, and is used to control the heating component according to the temperature detected by the temperature detection element, so that the temperature of the cleaning fluid is maintained within a preset temperature range. The control component is also electrically connected to the relative motion drive component and the ultrasonic generator, respectively, and is configured to: when the temperature detection element detects that the temperature of the cleaning fluid is within the preset temperature range, simultaneously control the relative motion drive component to drive the feed pelleting mold to move relative to the ultrasonic radiation surface, and control the ultrasonic generator to output drive power to the ultrasonic transducer, so as to drive the ultrasonic transducer to transmit ultrasonic vibration to the cleaning fluid through the ultrasonic radiation surface.

8. The ultrasonic cleaning machine for feed pelleting molds according to claim 1, characterized in that: The ultrasonic radiation surface is a plane; when the mold hole is located in the axial energy-receiving position of the mold hole, the vertical distance from the center of the opening of the mold hole facing the ultrasonic radiation surface to the ultrasonic radiation surface is 10mm to 40mm.

9. The ultrasonic cleaning machine for feed pelleting molds according to claim 1, characterized in that: The feed pelleting die supported by the die support assembly is a ring die; the die support assembly includes two spaced-apart support rollers, the axes of the two support rollers are parallel to each other and parallel to the central axis of the ring die, the two support rollers are respectively located on the lower sides of the ring die and jointly support the ring die, and the outer peripheral surfaces of the two support rollers are respectively in contact with the outer peripheral surface of the ring die; the relative motion drive assembly is used to drive the two support rollers to rotate in the same direction, so as to drive the ring die to rotate around its own central axis.

10. The ultrasonic cleaning machine for feed pelleting molds according to claim 9, characterized in that: Each of the support rollers is supported at both ends by bearings on oppositely arranged roller fixing plates; the relative motion drive assembly includes a geared motor, a drive sprocket, two driven sprockets, and a chain. The drive sprocket is connected to the output shaft of the geared motor and is located above the two driven sprockets. The two driven sprockets are coaxially connected to one end of the two support rollers on the same side. The chain is wound around the drive sprocket and the two driven sprockets to drive the two support rollers to rotate in the same direction simultaneously.

11. The ultrasonic cleaning machine for feed pelleting molds according to claim 1, characterized in that: The top of the cleaning tank is open, and an inlet and an outlet are respectively provided on opposite sides of the cleaning tank. The outlet is located near the bottom of the cleaning tank, and a control valve is provided for the inlet and the outlet.

12. The ultrasonic cleaning machine for feed pelleting molds according to claim 1, characterized in that: The feed pelleting mold supported by the mold support assembly is a flat mold; the mold support assembly includes a support platform and a positioning part disposed on the support platform. The support platform is used to support the periphery of the flat mold, and the positioning part is used to restrict the flat mold from moving relative to the support platform in a direction parallel to the surface of the flat mold plate; the relative motion drive assembly is connected to the support platform for driving the support platform to rotate about an axis perpendicular to the surface of the flat mold plate, or to reciprocate in a direction parallel to the surface of the flat mold plate, so that the flat mold moves with the support platform, and the mold holes at different positions on the flat mold pass through the axial energy-receiving positions of the mold holes one after another.

13. A method for ultrasonic cleaning of feed pelleting molds, characterized in that: include: A feed pelleting mold with multiple die holes is supported in a cleaning tank containing cleaning liquid, such that at least a portion of the area on the feed pelleting mold with the die holes is immersed in the cleaning liquid. An ultrasonic transducer coupled to the ultrasonic radiation surface of an ultrasonic generating component transmits ultrasonic vibrations to the cleaning fluid via the ultrasonic radiation surface in contact with the cleaning fluid, thereby forming an ultrasonic action zone in the cleaning fluid. During the process of applying ultrasonic action to the cleaning liquid through the ultrasonic transducer, the feed pelleting mold is driven to move relative to the ultrasonic radiation surface, so that the die holes at different positions on the feed pelleting mold pass through the axial energy-receiving positions of the die holes one after another. When the die hole of the feed pelleting mold is located in the axial energy-receiving position of the die hole, the opening of the die hole facing the ultrasonic radiation surface is opposite to the ultrasonic radiation surface. The distance between the opening and the ultrasonic radiation surface makes the opening located within the ultrasonic action zone, and the ray extending outward from the center of the opening along the axial direction of the die hole intersects the ultrasonic radiation surface.

14. The ultrasonic cleaning method for feed pelleting molds according to claim 13, characterized in that: During the process of driving the feed pelleting mold to move relative to the ultrasonic radiation surface, so that the die holes at different positions on the feed pelleting mold pass through the axial energy-receiving positions of the die holes one after another, the ultrasonic generator drives the ultrasonic transducer with a periodically changing output frequency and outputs driving power to the ultrasonic transducer in an intermittent pulse manner. The output frequency of the ultrasonic generator changes periodically between the lower limit frequency and the upper limit frequency of the sweep frequency. Both the lower limit frequency and the upper limit frequency are within the range of 20kHz to 40kHz, and the difference between the upper limit frequency and the lower limit frequency is 2kHz to 6kHz. The intermittent pulse mode includes periodically alternating ultrasonic output periods and intermittent periods, during which the driving power output to the ultrasonic transducer is stopped, or the driving power output to the ultrasonic transducer is lower than that of the ultrasonic output periods.

15. The ultrasonic cleaning method for feed pelleting molds according to claim 13, characterized in that: The cleaning fluid is water; the cleaning fluid is heated to a preset temperature range and maintained within the preset temperature range; while maintaining the temperature of the cleaning fluid within the preset temperature range, the ultrasonic generator is controlled to output driving power to the ultrasonic transducer, so as to drive the ultrasonic transducer to transmit ultrasonic vibrations to the cleaning fluid through the ultrasonic radiation surface, and during the process of the ultrasonic transducer transmitting ultrasonic vibrations to the cleaning fluid, the feed pelleting mold is driven to move relative to the ultrasonic radiation surface; the preset temperature range is 20℃~80℃, preferably 30℃~70℃, more preferably 50℃~60℃.

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