Dust-free and environment-friendly paper tube cutting device

Abstract

This invention relates to the field of paper tube cutting technology, specifically to a dust-free and environmentally friendly paper tube cutting device, including a paper tube clamping mechanism, a feeding mechanism, and a saw blade; it also includes an airflow shield covering the saw blade, the inner wall of which is shaped like an Archimedean spiral volute; the inner wall of the airflow shield is provided with boundary layer peeling ribs, the ends of which extend toward the saw blade and maintain a gap with it; a cold air knife is mounted on the airflow shield, the cold air knife including a gas distribution chamber and nozzles, the gas distribution chamber being configured to output low-temperature cold air, and multiple nozzles being arranged on the gas distribution chamber and pointing toward the saw blade. This invention, by using an Archimedean spiral shield with boundary layer peeling ribs to disrupt the airflow barrier, combined with the counter-current jet of the cold air knife for cooling and dust suppression, achieves efficient dust removal and collection and smoke suppression, thus achieving the purpose of dust-free, noise-reducing, and environmentally friendly cutting.

Description

Technical Field

[0001] This invention relates to the field of paper tube cutting technology, specifically to a dust-free and environmentally friendly paper tube cutting device. Background Technology

[0002] As the supporting framework for films, metal foils, and textiles, the dimensional accuracy and end-face quality of paper tubes directly affect the winding efficiency of downstream products. Paper tubes are typically made of kraft paper through a spiral winding process and cured with sodium silicate or starch-based adhesives, forming a multi-layered orthotropic composite material structure. In mass production, long tubular paper tubes need to be cut into finished products of different specifications. Currently, the industry mainly uses circular sawing technology, which separates the material by radially cutting into the paper tube with a high-speed rotating saw blade. This technology has advantages such as high processing efficiency, wide applicability to wall thicknesses, and simple equipment structure, making it the mainstream cutting method in the paper tube processing field. A typical sawing device includes components such as a swing arm or linear slide feed mechanism, a high-speed rotating saw blade, and a paper tube clamping and positioning mechanism.

[0003] Existing sawing technology suffers from severe dust pollution. During the cutting process, the material within the kerf volume is instantly pulverized into micron-sized fiber fragments and adhesive particles. Simultaneously, mineral fillers such as calcium carbonate and talc in the paper undergo interfacial separation and breakage under the pressure of the blade. The high-speed rotating saw blade (linear velocity reaching 40-60 m / s) creates a powerful centrifugal airflow field around it, ejecting dust with high kinetic energy along the tangential direction. Traditional dust hoods are fixed behind the saw blade, but due to the boundary layer airflow barrier effect generated by the rotating saw teeth, fine dust is trapped in the turbulent layer on the saw blade surface, resulting in a low capture rate of fine dust and failing to meet occupational disease prevention and workshop air quality standards.

[0004] In the cutting process of paper tubes with high adhesive content or those that have become brittle due to aging, the problem of pyrolysis dust generation caused by tool wear is particularly prominent. When the cutting speed is extremely high (such as the speed of a high-speed steel saw blade greater than 3000 RPM), the mineral fillers (calcium carbonate, talc, etc.) in the paper tube exert a strong abrasive effect on the cutting edge, leading to accelerated wear on the back face. After the cutting edge becomes dull, the cutting process evolves into a plowing effect, and the frictional heat increases sharply. This causes sodium silicate or starch-based adhesives to carbonize at high temperatures, producing micron-sized pyrolysis dust (coking particles). These pyrolysis dust particles are smaller than PM2.5 and have stronger respiratory penetration and health hazards, resulting in a continuous exceedance of the concentration of suspended particulate matter in the workshop air.

[0005] Therefore, a dust-free and environmentally friendly paper tube cutting device is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a dust-free and environmentally friendly paper tube cutting device, which solves the problems of fine dust escaping with the airflow and the high-temperature carbonization of adhesives producing smoke during paper tube cutting. By using an Archimedean spiral shield with boundary layer peeling ribs to break the airflow barrier, and in conjunction with a cold air knife for reverse jet cooling and dust suppression, the device achieves efficient peeling and collection of fine dust and smoke suppression, thus achieving the goal of dust-free, noise-reducing and environmentally friendly cutting.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A dust-free and environmentally friendly paper tube cutting device includes a paper tube clamping mechanism, a feeding mechanism, and a saw blade;

[0009] It also includes an airflow shield covering the saw blade, the inner wall of which is shaped like an Archimedean spiral volute. Centrifugal force is used to throw the dust-laden airflow towards the wall surface, and the diffusion effect is used to reduce the airflow velocity, facilitating sedimentation and collection. Simultaneously, the Archimedean spiral structure can precisely match the velocity gradient of the flow field generated by the saw blade's rotation, allowing the dust-laden airflow to form a stable, smooth, streamlined flow within the shield, avoiding turbulent rebound caused by abrupt changes in the flow channel cross-section. This ensures that fiber fragments and mineral particles of different densities can migrate outward along specific trajectories, improving gas-solid separation efficiency. Furthermore, this gradually expanding spiral flow channel can effectively attenuate high-frequency aerodynamic noise caused by the high-speed rotating saw blade, and eliminates resonant standing waves of sound waves in narrow cavities through a smooth flow field transition, thereby reducing dust pollution while lowering noise levels in the cutting workshop.

[0010] The inner wall of the airflow shield is provided with boundary layer peeling ribs, the ends of which extend toward the saw blade and maintain a gap with the saw blade; this is to block the rotating airflow on the surface of the saw blade, destroy the airflow barrier, and force fine dust to detach from the turbulent layer; that is, by creating discontinuous pressure abrupt change points in the near-wall region of the saw blade, the laminar sublayer stability of the boundary layer is destroyed, causing the micron-sized dust locked on the surface of the saw blade to lose its aerodynamic carrier and be forcibly ejected to the inner wall of the airflow shield under the action of centrifugal force; at the same time, this periodic forced peeling of the fluid boundary layer can destroy the thermal boundary layer on the surface of the saw blade, enhance the convective heat transfer coefficient between the saw blade and the surrounding air, that is, accelerate the heat dissipation of the saw blade.

[0011] A cold air knife mounted on an airflow shroud includes an air distribution chamber and nozzles. The air distribution chamber is configured to output low-temperature cold air, and multiple nozzles are arranged on the air distribution chamber and point towards the saw blade. This cooling process protects the saw blade and utilizes the low temperature of the saw blade to embrittle the paper fibers, making the paper tube easier to cut. Simultaneously, the blowing from the nozzles and the suction from the dust outlet clean the dust on the saw blade. Furthermore, the high-pressure airflow above the saw blade's cutting point can form a high-momentum air curtain barrier, using the local positive pressure air seal effect to suppress the initial rising momentum of dust at the cutting point and prevent ultrafine dust from escaping to the operating side before being sucked into the shroud.

[0012] Preferably, the windward surface of the boundary layer peeling rib is a concave arc surface; this allows the high-speed dust-laden airflow to naturally adhere to the arc surface, transforming the chaotic turbulent scattering into a laminar flow with clear directionality, accurately pushing the dust into the through hole, and preventing the dust from rebounding back to the saw blade surface due to impact with the planar rib, thus avoiding secondary pollution.

[0013] Preferably, the boundary layer peeling ribs are radially distributed along the inner wall of the airflow shield, and the boundary layer peeling ribs are inclined to the radial direction of the saw blade. This inclination angle superimposes the radial outward velocity component on the tangential velocity of the particles, synthesizing a spiral escape trajectory that matches the suction direction of the dust outlet, preventing dust from accumulating and clogging at the root of the ribs. In addition, this inclination angle can also change the incident angle of particle impact, converting vertical impact into tangential friction, which greatly reduces the erosion and wear of the boundary layer peeling rib surface by dust particles.

[0014] Preferably, the length of the boundary layer stripping ribs increases along the direction of saw blade rotation to conform to the physical law that the boundary layer gradually thickens along the flow direction during fluid rotation; the shorter upstream boundary layer stripping ribs treat the initially thinner boundary layer, while the longer downstream boundary layer stripping ribs intercept the fully developed thickened turbulent layer, thereby achieving equivalent interception in the entire circumferential direction and ensuring uniform stripping efficiency in each region.

[0015] Preferably, the airflow shield includes a main cavity for accommodating the saw blade and a secondary cavity located around the main cavity. The openings of both the main cavity and the secondary cavity are located below the saw blade cutting area, and the main cavity and the secondary cavity are internally connected. The secondary cavity is provided with a dust discharge port. Dust adhering to the saw blade is difficult to remove. Therefore, the dual-chamber design enhances the adsorption force of the main cavity on the dust on the saw blade, while the secondary cavity has a relatively lower suction force. It uses its large opening to adsorb dust that has escaped from the air over a large area.

[0016] Preferably, the inner wall of the airflow shield has through holes, which fit the windward side of the boundary layer peeling ribs, and the through holes are designed as crescent-shaped structures that are wide in the middle and narrow at both ends. The area directly opposite the saw blade has the most dust, so the through holes are widest in the middle to avoid clogging. They gradually narrow towards both sides according to the dust distribution characteristics, and the narrow openings at both ends maintain the edge flow velocity through the throttling effect, preventing the formation of low-speed vortex zones in the dead corners of the through holes, which would lead to dust deposition. In addition, the crescent-shaped variable cross-section channel can also change the airflow frequency through its own structure, avoiding a single frequency whistling, and further acting as a silencer, achieving dual noise reduction in conjunction with the volute structure.

[0017] Preferably, skirts are provided at the openings of the main cavity and the secondary cavity, and the skirts elastically contact the paper tube; the elastic fit of the skirts in the cutting area creates a semi-closed negative pressure cavity, which effectively prevents the external airflow from interfering with the flow field inside the cover, ensuring that the suction force generated by the dust discharge port is concentrated on the cutting dust point, and improving the effective air intake rate of the dust removal system.

[0018] Preferably, the jet direction of the nozzle is opposite to the rotational tangent direction of the saw blade to increase the relative velocity between the nozzle airflow and the saw blade surface, enhance the aerodynamic shear stress, and thus peel off the semi-molten adhesive residue adhering to the saw blade teeth, preventing it from accumulating and hardening. Furthermore, by utilizing the relative velocity difference, the Reynolds number is increased, thereby placing the convective heat transfer in the turbulence enhancement zone, so that the cooling of the saw blade can be maintained with a small amount of air consumption.

[0019] Preferably, the nozzle includes a front nozzle and a side nozzle. The front nozzle faces the saw blade teeth, and the side nozzle is inclined to the front nozzle and faces the saw blade substrate. This eliminates the temperature difference between the saw blade teeth and the saw blade substrate, preventing the saw blade from warping due to uneven heating. At the same time, the airflow from the side nozzle forms an air bearing effect on the substrate surface, suppressing high-speed chattering of the thin saw blade and improving the flatness of the cut surface.

[0020] Preferably, the inner hole and outer wall of the nozzle are both gradually tapered, and the small ends of the inner hole and outer wall of the nozzle face the saw blade; the converging structure of the inner hole accelerates the nozzle, converting the air pressure energy into high-speed kinetic energy; the conical design of the outer wall reduces its projected area facing the particle flow, and uses the streamlined surface to guide the dust-laden airflow to slide over rather than collide head-on, thereby extending the service life of the nozzle in harsh abrasive environments.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1. This invention provides boundary layer peeling ribs around the saw blade. By extending their ends into the rotating airflow layer of the saw blade, the ribs block and destroy the air barrier on the surface of the saw blade, causing the fine dust that was originally trapped by the airflow to detach from the saw blade under centrifugal force and be thrown into the protective cover. At the same time, in conjunction with the cold air knife, low-temperature cold air is continuously output to the saw blade, which reduces the temperature of the saw blade and prevents the adhesive in the paper tube from undergoing pyrolysis and carbonization due to frictional heat, thereby reducing the generation of smoke and dust.

[0023] 2. The inner wall of the airflow shield of the present invention adopts the shape of an Archimedean spiral volute, which guides the high-speed dust-laden airflow to decelerate in the gradually expanding flow channel and promotes dust settling by utilizing the diffusion effect; the windward surface of the boundary layer peeling rib is designed as a concave arc surface, which guides the dust to the crescent-shaped through hole to prevent the dust from impacting and rebounding back to the saw blade; this gradual flow channel design and through hole structure can also smooth the airflow pulsation and reduce the noise generated by airflow impact and eddies.

[0024] 3. The nozzle jet direction of the present invention is opposite to the rotation direction of the saw blade, forming a high-pressure air curtain above the cutting point to suppress the dust from the cutting point and use the airflow shearing force to peel off the adhering material on the saw teeth; at the same time, the side nozzle sprays airflow toward the saw blade substrate, forming an air cushion on the surface of the thin saw blade, which provides lateral support for the high-speed rotating saw blade, reduces the lateral vibration of the saw blade when cutting hard paper tubes, and ensures the flatness of the cut surface. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall isometric structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the saw blade and airflow shield structure of the present invention;

[0027] Figure 3 This is an isometric structural diagram of the internal section of the airflow shield of the present invention;

[0028] Figure 4 For the present invention Figure 3 Enlarged diagram of part A in the middle;

[0029] Figure 5 This is a schematic diagram of the internal cross-sectional main view of the airflow shield structure of the present invention;

[0030] Figure 6 This is a schematic diagram of the external structure of the through hole in this invention;

[0031] Figure 7 This is a side view of the airflow shield structure of the present invention;

[0032] Figure 8 For the present invention Figure 7 Enlarged schematic diagram of part B in the middle.

[0033] In the diagram: 1. Paper tube clamping mechanism; 2. Feeding mechanism; 3. Saw blade; 4. Airflow shield; 41. Main chamber; 42. Secondary chamber; 421. Dust outlet; 43. Through hole; 44. Skirt; 5. Boundary layer peeling rib; 6. Cold air knife; 61. Air distribution chamber; 62. Nozzle; 621. Front nozzle; 622. Side nozzle. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Please see Figures 1 to 8This invention provides a dust-free and environmentally friendly paper tube cutting device, the technical solution of which is as follows:

[0036] Reference Figures 1 to 5 A dust-free and environmentally friendly paper tube cutting device includes a paper tube clamping mechanism 1, a feeding mechanism 2, and a saw blade 3. The paper tube clamping mechanism 1 preferably adopts a structure of V-shaped pneumatic clamping block and intermediate support roller to avoid the cutting area. The feeding mechanism 2 adopts a screw module to drive the airflow cover 4. There are two feeding directions: one is to drive the saw blade 3 to feed along the paper tube axis to adjust the axial length of the paper tube to be cut; the other is to drive the saw blade 3 to feed along the paper tube radially to cut the paper tube.

[0037] It also includes an airflow shield 4 covering the saw blade 3, the inner wall of which is in the shape of an Archimedean spiral volute;

[0038] The inner wall of the airflow shield 4 is provided with boundary layer peeling ribs 5, the ends of which extend toward the saw blade 3 and maintain a gap with the saw blade 3.

[0039] A cold air knife 6 is mounted on the airflow shield 4. The cold air knife 6 includes an air distribution chamber 61 and nozzles 62. The air distribution chamber 61 is configured to output low-temperature cold air. Multiple nozzles 62 are arranged on the air distribution chamber 61 and point towards the saw blade 3.

[0040] Without cooling, the cutting zone temperature of the high-speed rotating saw blade 3 can reach 80-120℃ when it contacts the rigid paper tube. Within this temperature range, sodium silicate or starch-based adhesives are in a viscoelastic state, their viscosity decreases, and the adhesive layer softens easily. The cold air knife 6 continuously sprays high-speed cold air at a temperature of 0℃ to -10℃ through the front nozzle 621 and the side nozzle 622, reducing the working temperature of the saw blade 3 (especially the tooth area) to 30-50℃. At this temperature, the bonding strength of sodium silicate increases by 20%-30%, and the brittleness coefficient of the paper fibers increases, making the paper tube more prone to breakage under the mechanical action of the saw teeth. To avoid excessive changes in outlet temperature due to fluctuations in input pressure, a pressure reducing valve and a check valve should be installed at the inlet of the air distribution chamber 61 to stabilize the pressure within the air distribution chamber 61. Simultaneously, a temperature sensor should be installed to monitor the cold air outlet temperature, with an allowable range of 0℃ to -12℃.

[0041] The airflow shield 4 is preferably made of wear-resistant stainless steel plate to improve durability; the initial radius of the Archimedean spiral volute inner wall is set to be slightly larger than the radius of the saw blade 3 (e.g., R+5mm), and its flow channel cross-sectional area increases linearly with the increase of the angle to ensure that the flow velocity of the dust-laden airflow decreases uniformly during the diffusion process; specifically, the Archimedean spiral profile of the inner wall of the airflow shield 4 satisfies the equation r = R + C + k · θ, where R is the radius of the saw blade 3, C is the initial gap (5mm), θ is the expansion angle (in radians), and the growth coefficient k ranges from 2 to 4mm / rad. This parameter setting can ensure that the airflow diffusion angle inside the shield is controlled between 7° and 10°, effectively preventing the separation of the airflow boundary layer;

[0042] The gap between the boundary layer peeling rib 5 and the side of the saw blade 3 should be controlled between 0.5mm and 2.0mm. This can effectively destroy the boundary layer and prevent mechanical interference caused by the end face jump of the saw blade 3 during high-speed rotation. The air distribution chamber 61 of the cold air knife 6 is connected to the vortex tube or industrial air cooler through a pipeline. Dry compressed air with an input pressure of 0.4-0.6MPa is used, and after cooling, cold air with an output temperature of 0℃ to -10℃ is output.

[0043] As one embodiment of the present invention, refer to Figure 4 The windward surface of the boundary layer peeling rib 5 is a concave arc surface; the radius of curvature of the concave arc surface of the boundary layer peeling rib 5 is preferably 2mm-5mm. When the high-speed rotating boundary layer airflow hits the arc surface, the fluid tends to adhere to the curved surface and flow, thereby regulating the originally disordered dust flow along the tangential direction into a controlled flow stream that converges towards the center of the boundary layer peeling rib 5; the boundary layer peeling rib 5 can be welded with hard alloy material and the surface is polished to reduce flow resistance.

[0044] As one embodiment of the present invention, refer to Figure 5 The boundary layer peeling ribs 5 are radially distributed along the inner sidewall of the airflow shield 4, and the boundary layer peeling ribs 5 are inclined to the radial direction of the saw blade 3. Specifically, the inclination angle of the boundary layer peeling ribs 5 (i.e., the angle between the center line of the boundary layer peeling ribs 5 and the radius passing through the root of the boundary layer peeling ribs 5) is set to 15° to 30°, and the inclination direction is opposite to the rotation direction of the saw blade 3. This allows dust particles to not only have a tangential deceleration effect when they collide with the boundary layer peeling ribs 5, but also generate an outward radial velocity component, thereby helping the dust to leave the area of ​​the saw blade 3 and enter the dust discharge channel more quickly, preventing dust from accumulating at the root of the ribs.

[0045] As one embodiment of the present invention, refer to Figure 5The length of the boundary layer peeling rib 5 increases along the direction of rotation of the saw blade 3; its increasing law matches the thickening law of the turbulent boundary layer on the surface of the saw blade 3; near the cutting point, the boundary layer is thinner, and the length of the first boundary layer peeling rib 5 is shorter (e.g., 2 mm); as the airflow rotates along the circumference, the boundary layer gradually develops and thickens, and the length of the subsequent boundary layer peeling rib 5 increases arithmetically (e.g., every other boundary layer peeling rib 5 increases by 2-3 mm) until the last rib can cover 1 / 4 to 1 / 3 of the effective cutting radius of the saw blade 3, thereby achieving an equivalent scraping effect in the entire circumference.

[0046] As one embodiment of the present invention, refer to Figure 3 and Figure 5 The airflow shield 4 includes a main cavity 41 that houses the saw blade 3 and a secondary cavity 42 located around the main cavity 41. The openings of both the main cavity 41 and the secondary cavity 42 are located below the cutting area of ​​the saw blade 3, and the main cavity 41 and the secondary cavity 42 are internally connected. The secondary cavity 42 has a dust discharge port 421. The main cavity 41 and the secondary cavity 42 are separated by a solid partition and connected only through a specific through-hole 43. The dust discharge port 421 is connected to a high-negative-pressure industrial dust collector. During operation, the secondary cavity 42 acts as a pressure stabilizing and settling chamber, maintaining a negative pressure state. Through the through-hole 43, it forms multi-point suction on the inner wall of the main cavity 41 to enhance the absorption of dust within the main cavity 41. The airflow shield 4 consists of two parts: the main cavity 41 and the secondary cavity 42. The main cavity 41 directly covers the saw blade 3. Structurally, the inner wall of the main cavity 41 is shaped like an Archimedean spiral volute, and its outline satisfies the polar coordinate equation r = R + C + k· on a horizontal cross-section (perpendicular to the axis of the saw blade 3). θ, this equation ensures that the flow channel expands uniformly;

[0047] In the axial direction (along the rotation axis of the saw blade 3), the width of the main cavity 41 depends on the thickness of the saw blade 3 and the working requirements, and is preferably the thickness of the saw blade 3 plus 15-25mm. An axial long axis-shaped air inlet is opened on each of the upper and lower sides of the saw blade 3, so that the airflow can enter the spiral flow channel evenly from around the cutting working area of ​​the saw blade 3; these two air inlets are located on the upper and lower inner walls of the main cavity 41 near the saw blade 3, respectively, and are in the shape of an elliptical arc with the long axis along the tangential direction.

[0048] The secondary cavity 42 surrounds the outer periphery of the main cavity 41, and the two are connected by crescent-shaped through holes 43 evenly distributed around the circumference. The outer wall of the secondary cavity 42 is smooth, and the inner wall forms a settling chamber with the partition of the main cavity 41. After dust enters through the through holes 43, it gradually settles in the low-speed flow area within the secondary cavity 42, and finally connects to the external dust collector through a single dust discharge port 421 (located near the central axis of the lower end of the airflow shield 4, at a 45° angle to the vertical downward direction).

[0049] The internal flow field design of the main cavity 41 and the secondary cavity 42 follows the principle of separation and settling. The main cavity 41 directly covers the saw blade 3. The high-speed rotating saw blade 3 generates a strong rotating airflow and centrifugal force field in this cavity, and the dust is centrifugally thrown towards the inner wall of the protective cover. The secondary cavity 42 is designed as a relatively spacious settling chamber with a lower airflow velocity.

[0050] As one embodiment of the present invention, refer to Figure 4 and Figure 6 The inner wall of the airflow shield 4 has through holes 43, which fit against the windward side of the boundary layer peeling rib 5. The through holes 43 are designed as crescent-shaped structures that are wide in the middle and narrow at both ends. The through holes 43 are located close to the root of the windward side of the boundary layer peeling rib 5. The crescent-shaped design, which is wide in the middle and narrow at both ends, follows the dust concentration distribution law: the linear velocity is highest at the saw teeth of the saw blade 3 (corresponding to the middle of the crescent), the dust particles have high kinetic energy and a large number of particles, so the opening is widened to increase the suction flux; while the airflow on both sides of the saw blade 3 (corresponding to the outer tip of the crescent) is relatively stagnant, and the dust is easily suspended, so a narrower gap is needed to utilize the high flow rate for suction. The through holes 43 are processed on the partition between the main cavity 41 and the secondary cavity 42 using laser cutting or wire cutting technology.

[0051] The specific parameters of the crescent-shaped structure of the through hole 43 are designed as follows: the maximum width of the middle part of the through hole 43 is 1mm to 3mm, the width of the two pointed ends is less than 0.5mm, the arc length of the through hole 43 along the circumferential direction corresponds to the central angle of 10° to 15°, in addition, the ratio of the total flow area of ​​all through holes 43 to the cross-sectional area of ​​the dust discharge port 421 should be controlled between 0.6 and 0.8 to ensure that the secondary cavity 42 maintains a static pressure difference of at least 200Pa relative to the main cavity 41, thereby ensuring the directional migration of dust.

[0052] As one embodiment of the present invention, refer to Figure 3 and Figure 5 Skirts 44 are provided at the openings of the main cavity 41 and the secondary cavity 42. Skirts 44 elastically contact the paper tube. Skirts 44 are made of wear-resistant rubber or flexible silicone. The side of skirts 44 that contacts the paper tube is designed as comb-shaped or brush-shaped to adapt to the curvature changes of paper tubes of different diameters and to maintain dynamic sealing during the cutting and feeding process, preventing external airflow from disturbing the internal flow field and preventing dust from falling.

[0053] As one embodiment of the present invention, refer to Figure 5The jet direction of nozzle 62 is opposite to the rotational tangential direction of saw blade 3. Opposite direction means the angle between the jet vector of nozzle 62 and the tangential vector of saw blade 3 at that point is greater than 90°, preferably 135°-150°. This range is based on the optimal balance between aerodynamic shear stress and air consumption. Within the linear velocity of saw blade 3 v_s = 25-40 m / s, the relative velocity is maximum and the shear stress is strongest when θ = 135°. When θ > 150°, the reverse effect weakens; therefore, 135°-150° is the optimal range. This reverse jet forms a strong aerodynamic shear force on the surface of saw blade 3, instantly dispersing the high-temperature air mass surrounding the saw teeth, forcibly breaking the thermal boundary layer, and improving the convective heat transfer coefficient. To ensure that the reverse jet can effectively penetrate the rotating airflow layer on the surface of saw blade 3, the vertical distance between the outlet end face of nozzle 62 and the circumference of the saw blade tooth tip should be maintained between 5 mm and 15 mm. Within this distance range, the pressure is 0.4-0.6 MPa. The jet center velocity attenuation is less than 30%, which is sufficient to overcome the centrifugal wind pressure generated by the rotation of saw blade 3.

[0054] As one embodiment of the present invention, refer to Figure 7 and Figure 8 The nozzle 62 includes a front nozzle 621 and a side nozzle 622. The front nozzle 621 faces the cutting teeth of the saw blade 3, while the side nozzle 622 is inclined to the front nozzle 621 and faces the base of the saw blade 3. The front nozzle 621 has a larger aperture (e.g., φ1.5-2.0mm) and is mainly responsible for flushing away the accumulated chips on the cutting teeth of the saw blade 3. The side nozzles 622 are arranged in pairs on both sides of the front nozzle 621, with smaller apertures (e.g., φ1.0-1.2mm) and are inclined inward toward the center of the base of the saw blade 3. This allows the side nozzles to cool the base while simultaneously creating an air bearing effect using a high-pressure air film, effectively suppressing the lateral vibration of the thin saw blade 3 during high-speed cutting. The angle between the axis of the side nozzle 622 and the side plane of the saw blade 3 is preferably 30° to 45°. This angle range, combined with an air supply pressure of 0.4-0.6MPa, can form a stable wedge-shaped air film on the surface of the saw blade 3 base, providing a stiffness of approximately 10-15. For pneumatic damping supports with N / mm diameter, it is important to note that the performance of air bearings is highly sensitive to changes in the air film clearance. In actual use, due to end face runout, wear, or bending of the saw blade 3, the air film thickness may vary between 0.1 and 0.5 mm, which can lead to fluctuations in lateral stiffness. Therefore, it should be ensured that the airflow temperature fluctuation is less than ±2℃ and the pressure fluctuation is less than ±0.05 MPa.

[0055] As one embodiment of the present invention, refer to Figure 8 The inner hole and outer wall of the nozzle 62 are both gradually tapered, and the small ends of the inner hole and outer wall of the nozzle 62 are both facing the saw blade 3. The inner hole adopts a constricted nozzle design to maximize the conversion of air source pressure energy into outlet kinetic energy. The outer wall is a streamlined cone, which is designed to reduce the erosion and wear of the dust-laden airflow on the outer wall of the nozzle 62 and prevent dust from accumulating and agglomerating on the end face of the nozzle 62.

[0056] Working principle: In order to achieve efficient collection of fine dust during the paper tube cutting process and prevent the adhesive from carbonizing at high temperature, after the device is started, the high-speed rotating saw blade 3 drives the surrounding air to form a boundary layer airflow with extremely high tangential velocity. This airflow usually locks in fine dust and forms an air barrier. At this time, the Archimedean spiral volute structure inside the airflow shield 4 uses its gradually expanding flow channel to gradually reduce the velocity of the dust-laden airflow thrown out by centrifugation, and the static pressure rises, converting kinetic energy into pressure energy, which facilitates the dust to settle in the secondary cavity 42.

[0057] To remove dust from the saw blade 3, the specific method is to use the boundary layer peeling ribs 5 set on the inner wall of the protective cover. When the airflow rotating with the saw blade 3 encounters the protruding boundary layer peeling ribs 5, the continuous flow lines are forcibly cut off, and the boundary layer is destroyed. The concave arc surface of the windward side of the boundary layer peeling ribs 5 guides the originally turbulent flow into a directional flow stream attached to the surface of the ribs, and directly guides it to the crescent-shaped through hole 43 at the root. Since the secondary cavity 42 is connected to the negative pressure dust removal equipment, a huge pressure gradient is formed at the through hole 43. The peeled dust instantly passes through the through hole 43 and enters the secondary cavity 42, completely detaching from the saw blade 3 area.

[0058] To address the issue of carbonization and dust generation caused by frictional heat in the adhesive within the paper tube, a cold air knife 6 system installed upstream of the cutting point is employed. Low-temperature cold air (0°C to -10°C) generated by the vortex tube is distributed through the air distribution chamber 61 and then ejected at high speed through the front nozzle 621 and the side nozzle 622. The reverse jet from the nozzle 62 not only forms a high-pressure air curtain above the cutting point of the saw blade 3, suppressing the initial dust rise through the air seal effect, but more importantly, the strong reverse airflow shearing action disrupts the thermal boundary layer on the surface of the saw blade 3, forcing convection heat transfer to rapidly remove cutting heat. Simultaneously, the airflow injected by the side nozzle 622 onto the saw blade 3 substrate forms an air cushion on the surface of the saw blade 3, providing aerodynamic damping and support for the high-speed rotating thin saw blade 3, suppressing lateral chatter, thereby improving the smoothness of the cut surface and extending the lifespan of the saw blade 3.

[0059] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A dust-free and environmentally friendly paper tube cutting device, comprising a paper tube clamping mechanism (1), a feeding mechanism (2), and a saw blade (3), characterized in that: It also includes an airflow shield (4) covering the saw blade (3), the inner wall of which is in the shape of an Archimedean spiral volute, in order to reduce the gas flow rate and cause the dust to settle by centrifugal force. The inner wall of the airflow shield (4) is provided with boundary layer peeling ribs (5). The ends of the boundary layer peeling ribs (5) extend toward the saw blade (3) and maintain a gap with the saw blade (3) to disrupt the rotating airflow and cause the dust to detach from the saw blade (3). A cold air knife (6) is installed on the airflow shield (4). The cold air knife (6) includes an air distribution chamber (61) and nozzles (62). The air distribution chamber (61) is configured to output low-temperature cold air. A plurality of the nozzles (62) are arranged on the air distribution chamber (61) and point towards the saw blade (3) to cooperate with the adsorption force inside the airflow shield (4) to remove dust from the surface of the saw blade (3) and cool the saw blade (3). The windward side of the boundary layer peeling rib (5) is a concave arc surface; The boundary layer peeling ribs (5) are radially distributed along the inner sidewall of the airflow shield (4), and the boundary layer peeling ribs (5) are inclined to the radial direction of the saw blade (3). The length of the boundary layer peeling ribs (5) increases along the direction of rotation of the saw blade (3); The airflow shield (4) includes a main cavity (41) for accommodating the saw blade (3) and a secondary cavity (42) located around the main cavity (41). The openings of the main cavity (41) and the secondary cavity (42) are both located below the cutting area of ​​the saw blade (3), and the main cavity (41) and the secondary cavity (42) are connected internally. The secondary cavity (42) is provided with a dust discharge port (421). The inner wall of the airflow shield (4) has a through hole (43), which fits the windward side of the boundary layer peeling rib (5), and the through hole (43) is set as a crescent-shaped structure that is wide in the middle and narrow at both ends.

2. The dust-free and environmentally friendly paper tube cutting device according to claim 1, characterized in that: Skirts (44) are provided at the openings of the main cavity (41) and the secondary cavity (42), and the skirts (44) elastically contact the paper tube.

3. The dust-free and environmentally friendly paper tube cutting device according to claim 1, characterized in that: The jet direction of the nozzle (62) is opposite to the rotational tangent direction of the saw blade (3).

4. A dust-free and environmentally friendly paper tube cutting device according to claim 1 or 3, characterized in that: The nozzle (62) includes a front nozzle (621) and a side nozzle (622), the front nozzle (621) facing the teeth of the saw blade (3), the side nozzle (622) being inclined to the front nozzle (621) and facing the base of the saw blade (3).

5. The dust-free and environmentally friendly paper tube cutting device according to claim 1, characterized in that: The inner hole and outer wall of the nozzle (62) are both gradually changed, and the small ends of the inner hole and outer wall of the nozzle (62) are facing the saw blade (3).

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