Shear mixing integrated complete equipment for old road regeneration asphalt and control method

Abstract

This invention discloses an integrated shear-mixing equipment and control method for recycled asphalt from old roads, relating to the technical field of recycled asphalt recycling equipment. The equipment includes a mixing chamber with a pair of spiral blades. When the spiral blades rotate and push the material, a high-pressure zone is formed on the front side and a low-pressure vortex stagnant zone is formed on the back side. Driven by the pressure difference, the material enters the internal guiding cavity from the front feed hole, is guided by the conical cavity, and is ejected from the back jet hole to form a self-circulating jet, directly scouring the low-pressure vortex stagnant layer on the back side. This structure can entrain the high-temperature material retained on the back side into the mainstream, eliminating local heat accumulation caused by the coupling of shear heat and frictional heat, and preventing excessively high local temperatures from causing thermal-oxidative aging of the asphalt.

Description

Technical Field

[0001] This invention relates to the technical field of equipment for recycling and utilizing recycled asphalt from old roads, and particularly to a complete set of equipment and control methods for the integrated shearing and mixing of recycled asphalt from old roads. Background Technology

[0002] Recycling and reusing asphalt mixtures from old roads not only saves sand, gravel, and asphalt resources but also reduces the land occupied by waste dumping and the pollution to the surrounding environment. Integrated shearing and mixing equipment for recycled asphalt from old roads is a complete processing unit that integrates high-speed shearing dispersion and low-speed mixing and homogenization of recycled asphalt from old roads into a single chamber. By sequentially shearing and tearing old asphalt lumps and uniformly blending recycling agents and new asphalt within the same chamber, it effectively shortens the process flow and reduces equipment footprint and temperature loss during material transfer. However, existing integrated shearing and mixing equipment for recycled asphalt from old roads still has the following drawbacks during use: Because shearing and mixing are integrated into the same cavity, the viscous heat dissipation in the gap between the rotor and stator in the shearing zone and the frictional heat between the spiral blades and the material in the mixing zone are directly coupled through the shared metal cavity wall and the material body. Furthermore, the heating and cooling jackets outside the cavity cannot accurately respond to localized hot spots, leading to localized heat accumulation caused by the coupling of shear and frictional heat within the integrated cavity, resulting in a gradient in asphalt aging. Specifically, at the junction of the shearing zone outlet and the mixing zone inlet, the high-temperature sheared material is pushed by the spiral blades before it has fully diffused, forming a stagnant layer in the low-pressure vortex zone on the back of the spiral blades. This stagnant layer continuously absorbs shear and frictional heat, with local temperatures exceeding 180 degrees Celsius or even reaching 200 degrees Celsius, causing thermo-oxidative aging of the asphalt, increasing asphaltene content, and decreasing ductility. Meanwhile, the material temperature near the jacket on the periphery of the cavity may be lower, resulting in insufficient regenerator penetration. The aforementioned temperature gradient problem can cause some areas of recycled asphalt mixture to age excessively while others are under-activated, ultimately resulting in uneven quality of the recycled asphalt mixture. This leads to significant fluctuations in road performance indicators such as Marshall stability and freeze-thaw splitting strength ratio, severely impacting the service life and driving safety of recycled asphalt pavement. Summary of the Invention

[0003] The purpose of this application is to provide an integrated set of equipment and control methods for shearing and mixing recycled asphalt from old roads, which can effectively solve the problems mentioned in the background art.

[0004] The integrated shearing and mixing equipment for recycled asphalt from old roads includes a mixing chamber with a pair of spiral blades. The spiral blades are equipped with a self-circulating jet de-stagnation mechanism. This mechanism includes multiple flow holes and guide nozzles. The flow holes are located on the spiral blades, and their axes are inclined at a certain angle to the axis of the spiral conveying mixing shaft on the spiral blades. The flow holes include a front feed hole, an internal guide cavity, and a back jet hole. The front feed hole is located on the material pushing surface of the spiral blades, and the back jet hole is located on the low-pressure stagnant surface of the spiral blades. The front feed hole and the back jet hole are connected by the internal guide cavity. The internal guide cavity is a conical structure with a gradually increasing diameter from the front feed hole to the back jet hole. The guide nozzle is located on the back jet hole.

[0005] Preferably, the flow guide nozzle has a streamlined curved surface that mimics the gill arch of a fish. The inlet of the flow guide nozzle is circular, and the outlet is flat and elongated. The curved surface gradually expands along the flow direction.

[0006] Preferably, a one-way valve is provided in the internal guide cavity; when the pressure on the front of the spiral blade is higher than the pressure in the internal guide cavity, the material is allowed to push the one-way valve to open.

[0007] Preferably, the one-way valve includes a mounting bracket, a stepped shaft, a sealing plug, and a compression spring; the mounting bracket is disposed in the internal flow guide cavity, the stepped shaft is coaxially inserted into the mounting bracket, the sealing plug is coaxially disposed on the stepped shaft, and the outer diameter of the sealing plug is larger than the diameter of the front feed hole; a receiving cavity is provided inside the mounting bracket, the compression spring is disposed in the receiving cavity, and the compression spring is sleeved at the stepped position of the stepped shaft; when the compression spring is unrestrained, it is allowed to push the stepped shaft to move so that the sealing plug abuts against the inner wall of the internal flow guide cavity.

[0008] Preferably, the mixing chamber is equipped with an internal wall temperature equalization mechanism, which is used to form a uniform temperature field on the wall surface of the mixing chamber, thereby reducing the temperature of the material inside the mixing chamber.

[0009] Preferably, the inner wall temperature equalization mechanism includes a flexible phase change heat storage airbag; multiple dovetail grooves are opened along the length of the mixing chamber, and the flexible phase change heat storage airbag is set in the dovetail groove.

[0010] Preferably, the inner wall temperature equalization mechanism also includes wall heat dissipation fins, which are arranged in parallel within the dovetail groove, and the back of the flexible phase change heat storage airbag is provided with a groove that matches the wall heat dissipation fins.

[0011] Preferred: The flexible phase change heat storage airbag is filled with a paraffin-based composite phase change material; the paraffin-based composite phase change material is prepared by mixing paraffin with expanded graphite and nano-alumina, and is injected into the flexible phase change heat storage airbag through the injection port in a heated and molten state. After injection, the injection port is sealed with a sealing plug and high-temperature resistant sealant.

[0012] Preferably, a miniature pressure relief valve is provided on one side of the flexible phase change heat storage airbag; when the internal pressure of the flexible phase change heat storage airbag rises to the set opening pressure, the spring-loaded valve disc of the miniature pressure relief valve is pushed open by the internal pressure, and the gas in the flexible phase change heat storage airbag is released through the valve.

[0013] The control method for the integrated shearing and mixing equipment for recycled asphalt from old roads, using the aforementioned integrated shearing and mixing equipment for recycled asphalt from old roads, specifically includes the following steps: Step 1, Pressure-building jet: Start the equipment, a pair of spiral blades in the mixing chamber rotate in opposite directions, their material pushing surfaces push the recycled asphalt material from the old road forward, forming a high-pressure zone on the front and a low-pressure vortex stagnant zone on the back; the high-pressure material on the front, driven by the pressure difference, enters the internal guide cavity through the front feed hole, and flows along the inclined flow holes through the aperture... After the gradually enlarging conical guide cavity, the jet is injected into the low-pressure stagnant zone through the jet hole on the back, forming a self-circulating jet; Step 2, jet homogenization: The self-circulating jet enters the guide nozzle and is shaped into a flat and long fan-shaped diffusion jet by the streamlined curved surface of its fish gill arch. It washes the low-pressure vortex stagnant layer on the back of the spiral blades over a large area, entraining the high-temperature stagnant material into the mainstream and eliminating the local heat accumulation caused by the coupling of shear heat and frictional heat; At the same time, the jet disturbance, together with the opposing push of a pair of spiral blades, makes the material uniformly mixed and temperature homogenized before being conveyed forward.

[0014] In summary, the technical effects and advantages of this invention are as follows: This invention employs a self-circulating jet de-stagnation mechanism. A front feed hole is formed on the material pushing surface of the spiral blades, and a back jet hole is formed on the low-pressure stagnant surface. These two holes are connected by a tapered internal guide cavity with gradually increasing diameter, and the axis of the flow hole is inclined to the axis of the spiral conveyor mixing shaft. When the spiral blades rotate and push the material, a high-pressure zone is formed on the front side, while a low-pressure vortex stagnant zone is formed on the back side. Driven by the pressure difference, the material enters the internal guide cavity from the front feed hole, is guided by the tapered cavity, and is ejected from the back jet hole to form a self-circulating jet, directly scouring the low-pressure vortex stagnant layer on the back side. This structure can entrain the high-temperature material stagnating on the back side into the mainstream, eliminating local heat accumulation caused by the coupling of shear heat and frictional heat, and preventing excessively high local temperatures from causing thermal-oxidative aging of the asphalt.

[0015] This invention incorporates a guide nozzle installed at the back jet orifice. The guide nozzle features a streamlined curved surface mimicking the gill arch of a fish, with a circular inlet and a flattened, elongated outlet. The curved surface gradually expands along the flow direction. The circular jet exiting the back jet orifice enters the guide nozzle, flows along the streamlined curved surface, and gradually expands, ultimately exiting from the flattened, elongated outlet to form a fan-shaped diffused jet. This structure increases the contact area between the jet and the low-pressure vortex stagnant layer, allowing the jet to cover a larger stagnant area and improving stagnant removal efficiency. Simultaneously, the biomimetic streamlined curved surface reduces jet energy loss, slows jet velocity decay, and extends the effective scouring distance, facilitating the elimination of localized heat accumulation over a larger area and further enhancing temperature homogenization.

[0016] This invention incorporates an internal wall temperature equalization mechanism. When the local temperature within the mixing chamber rises to the phase change temperature, the paraffin-based composite phase change material melts from a solid to a liquid state, absorbing latent heat and limiting further temperature increases. Conversely, when the local temperature decreases, the phase change material solidifies from a liquid to a solid state, releasing latent heat to replenish the heat. Wall-mounted heat dissipation fins enhance heat conduction between the airbags and the chamber wall, ensuring a balanced heat distribution among the airbags. This structure creates a uniform temperature field on the mixing chamber wall, reducing the temperature gradient of the materials within the chamber and preventing insufficient regenerator penetration due to lower temperatures in the surrounding materials. Simultaneously, a micro-pressure relief valve releases gas when the pressure inside the airbags is too high, ensuring safe operation of the airbags. This design improves the uniformity of the recycled asphalt mixture and extends the equipment's service life. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the present invention; Figure 2 This is a schematic diagram of the overall and partial cross-sectional three-dimensional structure of the present invention; Figure 3 This is a three-dimensional structural diagram of the present invention after the helical blades have been removed; Figure 4 This is a side view sectional view of the present invention; Figure 5 For the present invention Figure 4 Enlarged structural diagram of region A in the middle; Figure 6 This is a first-view three-dimensional structural diagram of the spiral blade of the present invention; Figure 7 This is a two-dimensional structural diagram of the helical blade of the present invention from a second perspective; Figure 8 This is a partial cross-sectional three-dimensional structural diagram of the helical blade of the present invention; Figure 9 For the present invention Figure 8 A magnified structural diagram of region B in the middle; Figure 10 This is a flowchart of the method of the present invention.

[0019] In the diagram: 1. Mixing bin; 2. Spiral blade; 3. Self-circulating jet de-stabilizing mechanism; 31. Front feed port; 32. Internal guide cavity; 33. Back jet port; 34. Guide nozzle; 35. One-way valve; 351. Mounting bracket; 352. Stepped shaft; 353. Sealing plug; 354. Receiving cavity; 355. Compression spring; 4. Inner wall temperature equalization mechanism; 41. Dovetail groove; 42. Flexible phase change heat storage airbag; 43. Wall heat dissipation fins. Detailed Implementation

[0020] 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.

[0021] Example 1: Please refer to Figures 1-2 and Figures 6-7 The integrated shearing and mixing equipment for recycled asphalt from old roads shown includes a mixing chamber 1, a pair of spiral blades 2 inside the mixing chamber 1, and a self-circulating jet de-stagnation mechanism 3 on the spiral blades 2. The self-circulating jet de-stagnation mechanism 3 includes multiple flow holes and guide nozzles 34. The multiple flow holes are opened on the spiral blades 2, and the axis of the flow holes is inclined at a certain angle to the axis of the spiral conveying mixing shaft on the spiral blades 2. The flow holes include a front feed hole 31, an internal guide cavity 32, and a back jet hole 33. The front feed hole 31 is opened on the material pushing surface of the spiral blades 2, and the back jet hole 33 is opened on the low-pressure stagnant surface of the spiral blades 2. The front feed hole 31 and the back jet hole 33 are connected by the internal guide cavity 32. The internal guide cavity 32 is a conical structure with the diameter gradually increasing from the front feed hole 31 to the back jet hole 33. The guide nozzle 34 is set on the back jet hole 33.

[0022] It should be noted that when the equipment is started, a pair of spiral blades 2 in the mixing chamber 1 rotate in opposite directions. The material pushing surface of the spiral blades 2 pushes the recycled asphalt material from the old road forward, forming a high-pressure zone on the front and a low-pressure vortex stagnant zone on the back. Due to the pressure difference between the front and back, the high-pressure material on the front enters the internal guide cavity 32 through the front feed hole 31, flows through the tapered internal guide cavity 32 with gradually increasing diameter through the inclined flow hole, and is ejected from the back jet hole 33, forming a self-circulating jet. The self-circulating jet directly washes the low-pressure vortex stagnant layer on the back of the spiral blades 2, entraining the high-temperature stagnant material into the mainstream.

[0023] The self-circulating jet stagnation elimination mechanism 3 uses inclined flow holes on the spiral blades 2 to drive the material self-circulation by utilizing the natural pressure difference between the front and back sides when the spiral rotates. It can form a jet to scour the stagnant layer on the back side without additional power, which can effectively eliminate the local heat accumulation caused by the coupling of shear heat and friction heat, and avoid the asphalt thermal oxidative aging caused by excessive local temperature. At the same time, the inclined flow holes make the material flow path the shortest and the pressure loss the smallest, which helps to reduce the energy consumption of the equipment.

[0024] See Figures 8-9 The flow guide nozzle 34 is a streamlined curved surface that imitates the gill arch of a fish. The inlet of the flow guide nozzle 34 is circular and the outlet is flat and elongated. The curved surface gradually expands along the flow direction.

[0025] It should be noted that the circular jet exiting from the jet hole 33 enters the guide nozzle 34 and flows along the streamlined curved surface of the fish gill arch. As the curved surface gradually expands along the flow direction and the outlet is elongated, the jet gradually diffuses and reshapes within the guide nozzle 34, eventually exiting from the elongated outlet to form a fan-shaped diffused jet, extensively covering the low-pressure vortex stagnation layer on the back of the spiral blade 2. The guide nozzle 34, through its biomimetic streamlined curved surface, shapes the circular jet into an elongated fan-shaped diffused jet, increasing the contact area between the jet and the stagnation layer, improving the stagnation elimination efficiency. Simultaneously, the streamlined curved surface reduces jet energy loss, allowing for a longer effective scouring distance, which is beneficial for eliminating localized heat accumulation over a larger area.

[0026] See Figures 8-9 An internal flow guide cavity 32 is provided with a one-way valve 35. The one-way valve 35 includes a mounting bracket 351, a stepped shaft 352, a sealing plug 353, and a compression spring 355. The mounting bracket 351 is located in the internal flow guide cavity 32. The stepped shaft 352 is coaxially inserted into the mounting bracket 351. The sealing plug 353 is coaxially located on the stepped shaft 352, and the outer diameter of the sealing plug 353 is larger than the diameter of the front feed hole 31. The mounting bracket 351 has a receiving cavity 354. The compression spring 355 is located in the receiving cavity 354 and is sleeved on the stepped position of the stepped shaft 352.

[0027] It should be noted that when the pressure on the front of the spiral blade 2 is higher than the pressure in the internal guide cavity 32, the material pressure acts on the sealing plug 353 and pushes the stepped shaft 352 to move axially along the mounting bracket 351. The stepped position of the stepped shaft 352 compresses the compression spring 355, causing the sealing plug 353 to disengage from the inner wall of the internal guide cavity 32. The one-way valve 35 is opened to allow the material to pass through. When the front pressure decreases, the compression spring 355 loses its pressure restriction and pushes the stepped shaft 352 to move in the opposite direction, causing the sealing plug 353 to abut against the inner wall of the internal guide cavity 32. The one-way valve 35 is closed.

[0028] The one-way valve 35, through the cooperation of the mounting bracket 351, the stepped shaft 352, the sealing plug 353, and the compression spring 355, realizes the automatic opening and closing function based on pressure difference. The outer diameter of the sealing plug 353 is larger than the diameter of the front feed hole 31 to ensure the sealing reliability when closed. The compression spring 355 is sleeved at the stepped position of the stepped shaft 352 to make the opening and closing action smooth and reliable, which is conducive to ensuring the smooth flow of the self-circulating jet channel and the stable operation of the equipment.

[0029] See Figures 1-4 The mixing chamber 1 is equipped with an inner wall temperature equalization mechanism 4, which is used to form a uniform temperature field on the wall of the mixing chamber 1, thereby reducing the temperature of the material in the mixing chamber 1.

[0030] It should be noted that when the material in the mixing chamber 1 experiences a local temperature rise, the inner wall temperature equalization mechanism 4 absorbs the excess heat in that area and conducts it to the area with a lower temperature. When the material in the mixing chamber 1 experiences a local temperature drop, the inner wall temperature equalization mechanism 4 releases the stored heat to replenish that area, thereby forming a uniform temperature field on the wall of the mixing chamber 1 and reducing the temperature gradient of the material in the chamber.

[0031] The inner wall temperature equalization mechanism 4 can form a uniform temperature field on the wall of the mixing chamber 1, effectively reducing the temperature gradient of the material inside the chamber and avoiding insufficient penetration of the recycling agent due to the low temperature of the outer material. At the same time, it works with the self-circulating jet stagnation elimination mechanism 3 to eliminate local heat accumulation inside, achieving all-round temperature equalization from the inner wall to the center, which is conducive to improving the quality uniformity of the recycled asphalt mixture.

[0032] See Figures 1-5 The inner wall temperature equalization mechanism 4 includes a flexible phase change heat storage airbag 42. Multiple dovetail grooves 41 are opened along the length of the mixing chamber 1, and the flexible phase change heat storage airbag 42 is disposed in the dovetail grooves 41.

[0033] It should be noted that when the local temperature in the mixing chamber 1 rises to the phase change temperature, the flexible phase change heat storage airbag 42 in the dovetail groove 41 absorbs heat, causing the internal phase change material to melt from solid to liquid, thus limiting the temperature from rising further. When the local temperature drops below the phase change temperature, the phase change material in the flexible phase change heat storage airbag 42 solidifies from liquid to solid and releases latent heat, replenishing the heat in that area. The barbed structure of the dovetail groove 41 prevents the flexible phase change heat storage airbag 42 from detaching under the action of material flow and the sweeping action of the spiral blades 2.

[0034] The flexible phase change heat storage airbag 42 achieves passive temperature homogenization through the latent heat effect of the phase change material. It can absorb peak heat and replenish low-temperature heat without additional power. The embedded installation of the dovetail groove 41 makes the airbag secure and easy to replace. The flexible surface can deform with the material pressure to increase the contact area, which is beneficial to enhance the heat exchange effect and temperature homogenization capability.

[0035] See Figure 5 The inner wall temperature equalization mechanism 4 also includes wall heat dissipation fins 43, which are arranged in parallel within the dovetail groove 41, and the back of the flexible phase change heat storage airbag 42 is provided with a groove that matches the wall heat dissipation fins 43.

[0036] It should be noted that when the flexible phase change heat storage airbag 42 absorbs heat, the heat is conducted through the groove on the back of the airbag to the wall heat dissipation fins 43 that are adapted to it. The wall heat dissipation fins 43 increase the contact area with the wall of the mixing chamber 1, and quickly conduct the heat to the chamber wall and distribute it to the adjacent low-temperature area airbags. When the flexible phase change heat storage airbag 42 needs to release heat, the wall heat dissipation fins 43 conduct the heat from the chamber wall to the airbag, so as to achieve a balanced distribution of heat among the airbags.

[0037] The heat dissipation fins 43 on the wall enhance the heat conduction between the airbag and the wall of the mixing chamber 1 by adapting and cooperating with the groove on the back of the flexible phase change heat storage airbag 42, so that heat can be exchanged quickly between the airbags, avoiding overheating or overcooling of a single airbag, which is conducive to improving the uniformity of the temperature field of the entire wall of the mixing chamber 1 and the response speed of phase change heat storage.

[0038] See Figures 4-5 The flexible phase change heat storage airbag 42 is filled with a paraffin-based composite phase change material, which is prepared by mixing paraffin, expanded graphite and nano-alumina. It is injected into the flexible phase change heat storage airbag 42 through the injection port while in a heated and molten state. After injection, the injection port is sealed with a sealing plug and high-temperature resistant sealant. It is understood that the paraffin-based composite phase change material is existing technology and will not be described in detail.

[0039] It should be noted that the paraffin-based composite phase change material melts from a solid to a liquid state when the temperature rises to the phase change temperature, absorbing a large amount of latent heat of phase change. When the temperature drops, it solidifies from a liquid state to a solid state, releasing the stored latent heat. Expanded graphite improves the thermal conductivity of the composite material, thus accelerating the heat charge and release rate. Nano-alumina improves the thermal stability and cycle life of the phase change material. The sealing plug at the injection port and the high-temperature resistant sealant ensure that the phase change material does not leak during long-term thermal cycling.

[0040] Paraffin-based composite phase change materials achieve efficient heat storage and release through the latent heat effect of paraffin. The addition of expanded graphite significantly improves the thermal conductivity, making the temperature response more rapid. The addition of nano-alumina improves thermal stability and cycle life. The infusion sealing process ensures the reliability of long-term use and helps to extend the service life and temperature uniformity effect of the inner wall temperature uniformity mechanism 4.

[0041] Example 2: The technical solution of this example differs from that of Example 1 in that: (See below) Figures 4-5 A miniature pressure relief valve is provided on one side of the flexible phase change heat storage airbag 42; it is understood that the miniature pressure relief valve is existing technology and will not be described in detail.

[0042] It should be noted that when the internal pressure inside the flexible phase change heat storage bag 42 rises to the set opening pressure due to the long-term high-temperature degradation of the phase change material and the generation of gas or local overheating, the spring-loaded valve disc of the miniature pressure relief valve is pushed open by the internal pressure, and the gas inside the flexible phase change heat storage bag 42 is released through the valve. When the internal pressure drops below the opening pressure, the spring pushes the valve disc to reset and close, preventing the phase change material from leaking.

[0043] The miniature pressure relief valve can automatically release gas when the internal pressure of the flexible phase change heat storage bladder 42 is too high, effectively preventing the bladder from rupturing and leaking due to excessive internal pressure, ensuring the safe operation of the inner wall temperature equalization mechanism 4. At the same time, the spring-loaded structure of the pressure relief valve ensures that it automatically closes after the pressure drops to the set value, avoiding leakage of phase change material, which is conducive to improving the safety of the equipment and the maintenance cycle.

[0044] See Figures 1-10The control method of the integrated shearing and mixing equipment for recycled asphalt from old roads adopts the aforementioned integrated shearing and mixing equipment for recycled asphalt from old roads. Specifically, it includes a pressure-building jet step and a jet homogenization step. In the pressure-building jet step, the equipment is started to make a pair of spiral blades 2 in the mixing chamber 1 rotate in opposite directions. The material pushing surface pushes the recycled asphalt material from the old road forward, forming a high-pressure zone on the front and a low-pressure vortex stagnant zone on the back. The high-pressure material on the front enters the internal guide cavity 32 through the front feed hole 31 under the pressure difference drive, and flows along the inclined... After passing through the tapered guide cavity with gradually increasing aperture, the flow through the flow hole is injected into the low-pressure stagnant zone from the back jet hole 33 to form a self-circulating jet. The jet mixing step is that the self-circulating jet enters the guide nozzle 34 and is shaped into a flat and long fan-shaped diffusion jet by the streamlined curved surface of its fish gill arch. It washes the low-pressure vortex stagnant layer on the back of the spiral blade 2 over a large area, entraining the high-temperature stagnant material into the mainstream and eliminating the local heat accumulation caused by the coupling of shear heat and frictional heat. At the same time, the jet disturbance, together with the opposing push of a pair of spiral blades 2, makes the material uniformly mixed and temperature homogenized before being conveyed forward.

[0045] It should be noted that after the equipment is started, the pressure-building jet step is executed first. A pair of spiral blades 2 rotate in opposite directions to create a high-pressure zone on the front and a low-pressure stagnant zone on the back. The material circulates under the pressure difference to form a jet. Then, the jet homogenization step is executed. The self-circulating jet is shaped into a fan-shaped diffused jet by the guide nozzle 34 to flush the stagnant layer on the back, and the high-temperature material is drawn into the mainstream to eliminate local heat accumulation. The two steps work together continuously to make the material complete temperature homogenization and uniform mixing during the forward conveying process.

[0046] The pressure-building jet step utilizes the natural pressure difference of the spiral rotation to form a self-circulating jet, which can be activated without additional power. The jet homogenization step uses the fan-shaped jet shaped by the guide nozzle 34 to flush the stagnant layer over a large area. The two steps work together to achieve a complete temperature control process from jet activation to stagnant elimination. This can effectively eliminate local heat accumulation in the integrated cavity, avoid the problem of asphalt aging gradient, and help improve the quality of recycled asphalt mixtures and the energy-saving effect of the equipment.

[0047] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A complete set of shearing and mixing equipment for recycled asphalt from old roads, comprising a mixing chamber (1), wherein a pair of helical blades (2) are provided inside the mixing chamber (1); characterized in that, The spiral blade (2) is provided with a self-circulating jet stagnation elimination mechanism (3); the self-circulating jet stagnation elimination mechanism (3) includes: Multiple flow holes are provided on the spiral blade (2), and the axis of the flow holes is inclined at a certain angle to the axis of the spiral conveying mixing shaft on the spiral blade (2). The flow holes include a front feed hole (31), an internal guide cavity (32), and a back jet hole (33). The front feed hole (31) is provided on the material pushing surface of the spiral blade (2), and the back jet hole (33) is provided on the low-pressure stagnant surface of the spiral blade (2). The front feed hole (31) and the back jet hole (33) are connected through the internal guide cavity (32). The internal guide cavity (32) is a conical structure with the diameter gradually increasing from the front feed hole (31) to the back jet hole (33). And a guide nozzle (34) is provided on the back jet hole (33).

2. The integrated shearing and mixing equipment for recycled asphalt from old roads according to claim 1, characterized in that, The guide nozzle (34) is a streamlined curved surface that imitates the gill arch of a fish. The inlet of the guide nozzle (34) is circular and the outlet is flat and elongated. The curved surface gradually expands along the flow direction.

3. The integrated shearing and mixing equipment for recycled asphalt from old roads according to claim 1, characterized in that, A one-way valve (35) is provided in the internal guide cavity (32); when the pressure on the front of the spiral blade (2) is higher than the pressure in the internal guide cavity (32), the material is allowed to push the one-way valve (35) to open.

4. The integrated shearing and mixing equipment for recycled asphalt from old roads according to claim 3, characterized in that, The one-way valve (35) includes a mounting bracket (351), a stepped shaft (352), a sealing plug (353), and a compression spring (355). The mounting bracket (351) is disposed in the internal flow guide cavity (32). The stepped shaft (352) is coaxially inserted into the mounting bracket (351). The sealing plug (353) is coaxially disposed on the stepped shaft (352), and the outer diameter of the sealing plug (353) is larger than the diameter of the front feed hole (31). The mounting bracket (351) has a receiving cavity (354). The compression spring (355) is disposed in the receiving cavity (354), and the compression spring (355) is sleeved on the stepped position of the stepped shaft (352). When the compression spring (355) loses its restraint, it is allowed to push the stepped shaft (352) to move so that the sealing plug (353) abuts against the inner wall of the internal flow guide cavity (32).

5. The integrated shearing and mixing equipment for recycled asphalt from old roads according to claim 1, characterized in that, The mixing chamber (1) is equipped with an inner wall temperature equalization mechanism (4), which is used to form a uniform temperature field on the wall of the mixing chamber (1) to reduce the temperature of the material in the mixing chamber (1).

6. The integrated shearing and mixing equipment for recycled asphalt from old roads according to claim 5, characterized in that, The inner wall temperature equalization mechanism (4) includes a flexible phase change heat storage airbag (42); a plurality of dovetail grooves (41) are provided in the mixing chamber (1) along its length direction, and the flexible phase change heat storage airbag (42) is disposed in the dovetail groove (41).

7. The integrated shearing and mixing equipment for recycled asphalt from old roads according to claim 6, characterized in that, The inner wall temperature equalization mechanism (4) also includes wall heat dissipation fins (43), which are arranged in parallel within the dovetail groove (41), and the back of the flexible phase change heat storage airbag (42) is provided with a groove that is compatible with the wall heat dissipation fins (43).

8. The integrated shearing and mixing equipment for recycled asphalt from old roads according to claim 6, characterized in that, The flexible phase change heat storage airbag (42) is filled with a paraffin-based composite phase change material. The paraffin-based composite phase change material is prepared by mixing paraffin with expanded graphite and nano-alumina. It is injected into the flexible phase change heat storage airbag through the injection port in a heated and molten state. After injection, the injection port is sealed with a sealing plug and high-temperature resistant sealant.

9. The integrated shearing and mixing equipment for recycled asphalt from old roads according to claim 8, characterized in that, A miniature pressure relief valve is provided on one side of the flexible phase change heat storage airbag (42); when the internal pressure of the flexible phase change heat storage airbag (42) rises to the set opening pressure, the spring-loaded valve disc of the miniature pressure relief valve is pushed open by the internal pressure, and the gas in the flexible phase change heat storage airbag (42) is released through the valve.

10. A control method for an integrated shearing and mixing system for recycled asphalt from old roads, characterized in that, The integrated shearing and mixing equipment for recycled asphalt from old roads as described in any one of claims 1-9 is adopted; Specifically, the following steps are included: Step 1, Pressure-building jet: Start the equipment, and a pair of spiral blades (2) in the mixing chamber (1) rotate towards each other. Their material pushing surface pushes the recycled asphalt material from the old road forward, so that a high-pressure zone is formed on the front and a low-pressure vortex stagnant zone is formed on the back. The high-pressure material on the front enters the internal guide cavity (32) through the front feed hole (31) under the pressure difference drive. After flowing through the tapered guide cavity with gradually increasing aperture along the inclined flow hole, it is injected into the low-pressure stagnant zone from the back jet hole (33) to form a self-circulating jet. Step 2, jet mixing: The self-circulating jet enters the guide nozzle (34), and is shaped into a flat and long fan-shaped diffusion jet by the streamlined curved surface of its fish gill arch. It washes the low-pressure vortex stagnant layer on the back of the spiral blade (2) over a large area, and entrains the high-temperature stagnant material into the mainstream, eliminating the local heat accumulation formed by the coupling of shear heat and frictional heat. At the same time, the jet disturbance, together with the opposing push of a pair of spiral blades (2), makes the material uniformly mixed and temperature homogenized before being transported forward.

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