A foaming apparatus and method for foaming bitumen

Abstract

The application provides a foaming device and method for foamed asphalt, and relates to the technical field of road building material production, which comprises a heating storage tank, an asphalt pump, a foaming module and a chassis, the heating storage tank is installed on the chassis through a thermal displacement guide mechanism to release its thermal expansion stress; the asphalt pump is fixed on a rigid bottom plate with damping pads; the foaming module comprises at least two rotatable foaming units arranged side by side and having the same structure, the production capacity is linearly adjusted by increasing or decreasing the number of units, each foaming unit has coaxial multi-layer medium pipes, forms a central asphalt nozzle and a peripheral gas-water pre-mixed nozzle, and mixes and foams in the rotating foaming cavity, and the application also provides a corresponding foaming method, which comprises the steps of pre-preparing a module, on-site assembly, material conveying and distribution, rotating foaming and online cleaning, realizes rapid deployment of the device, vibration and thermal stress isolation, flexible expansion of production capacity and online maintenance, and improves the production efficiency, stability and economy of foamed asphalt.

Description

Technical Field

[0001] This invention relates to the field of road construction material production technology, specifically to a foaming device and method for foamed asphalt. Background Technology

[0002] Foamed asphalt, as an environmentally friendly warm-mix asphalt material, is widely used in road construction. Its production equipment typically includes core components such as heated storage tanks, delivery pumps, and foaming chambers. Traditional foamed asphalt foaming equipment often employs on-site welding and fixed installation, a method with several inherent drawbacks: First, on-site installation is time-consuming, and the alignment accuracy of components is difficult to guarantee, affecting the stability and reliability of equipment operation; second, the equipment layout is rigid and cannot be flexibly adjusted, often requiring the replacement of the entire large-scale equipment when increased production capacity is needed, resulting in high costs; third, equipment maintenance is inconvenient, and a failure of a single component can lead to a complete shutdown, severely impacting production efficiency.

[0003] Furthermore, traditional equipment lacks effective release and guidance mechanisms when dealing with the axial and radial thermal expansion stresses generated by heating in large heated storage tanks, which can easily lead to structural damage or connector failure during long-term operation. Simultaneously, vibrations generated by power components such as asphalt pumps are directly transmitted to the precision foaming unit, interfering with the stability of foam generation and affecting the quality of the final product. Existing technologies also lack systematic and economical solutions for achieving flexible and linear capacity expansion.

[0004] Therefore, there is an urgent need for a foamed asphalt foaming equipment and method that can overcome the above-mentioned defects, achieve rapid deployment, easy maintenance, flexible expansion and stable operation. Summary of the Invention

[0005] The purpose of this invention is to provide a modular, rapidly deployable, easy-to-maintain, and flexibly expandable foamed asphalt foaming equipment and method to overcome the shortcomings of existing technologies, such as complex installation, poor adaptability, and inconvenient maintenance.

[0006] This invention provides the following technical solution: A foaming device for foamed asphalt includes a heated storage tank, an asphalt pump, a foaming module, and a base frame. The asphalt pump is located between the heated storage tank and the foaming module, and is used to transport the asphalt in the heated storage tank to the foaming module. Its improvement lies in: The heating tank is mounted on the base frame via a thermal displacement guiding mechanism, which allows the heating tank to thermally expand along its axial and radial directions. The asphalt pump is fixedly installed on an integral rigid base plate, which is mounted on the base frame by vibration damping pads; The foaming module is mounted on the base frame and includes at least two identical foaming units arranged side by side, each foaming unit including a rotatable foaming cavity. The equipment's production capacity can be linearly adjusted by increasing or decreasing the number of foaming units.

[0007] Furthermore, the thermal displacement guiding mechanism includes a set of positioning units and multiple sets of guiding units arranged in a matrix. The positioning unit includes a set of fixing blocks secured between the base frame and the heating tank by first screws, used to determine the reference installation position of the tank. The guiding unit includes axial guide rails fixed to the base frame by second screws, radial guide blocks fixedly installed at the bottom of the heating tank, and axial guide blocks connecting the radial guide blocks and the axial guide rails. The axial guide blocks are slidably installed within the axial guide rails and have radial guide grooves formed on them, with the radial guide blocks guided within the radial guide grooves. The guiding extension direction of all axial guide rails is the same as the axial extension direction of the heating tank, and the guiding extension direction of all radial guide grooves is perpendicular to the axial extension direction of the heating tank. When the tank expands due to heat, starting from the fixing blocks, the axial guide blocks can slide along the axial guide rails to release axial displacement, while the radial guide blocks can slide within the radial guide grooves of the axial guide blocks to release radial displacement, thereby avoiding damage to the equipment structure caused by thermal stress.

[0008] Furthermore, the foaming unit includes: A fixed multi-layer medium pipe has three coaxially arranged independent flow channels inside, which are, from the inside to the outside, an asphalt flow channel, a water flow channel, and an air flow channel.

[0009] A cylindrical foaming cavity is rotatably fitted outside the multi-layer media pipe, with one end serving as the media inlet and the other as the foamed asphalt outlet. The tail end of the multi-layer media pipe extends into the foaming cavity through the media inlet, and its outermost flow channel (air flow channel) and the outlet of its middle flow channel (water flow channel) converge and connect to form an air-water premixed nozzle; the outlet of its innermost flow channel (asphalt flow channel) forms an asphalt nozzle. An outlet pipe is also connected to the foamed asphalt outlet end, and the outlet pipe is coaxially arranged with the multi-layer media pipe.

[0010] A transmission structure disposed on the outer periphery of the foaming cavity, and a driving device drivenly connected to the transmission structure, for driving the foaming cavity to rotate around the axis of the multilayer medium pipe and the outlet pipe.

[0011] Preferably, the asphalt nozzle is flared outwards towards the foaming cavity, and the ejection end of the air-water premixed nozzle is located on the outer wall of the flared section of the asphalt nozzle. This structure allows the atomized air-water mixture to surround the asphalt jet ejected from the central flared nozzle, achieving initial encapsulation and mixing, creating favorable conditions for subsequent full foaming.

[0012] Preferably, the inner wall of the foaming cavity is provided with at least one spiral guide rib extending from the medium inlet end to the foamed asphalt outlet end. When the cavity rotates, the spiral guide rib generates a strong shearing force and axial propulsion force on the mixture inside the cavity, greatly enhancing the mixing effect.

[0013] Preferably, the inner wall of the foaming cavity is further provided with a guide cone ring with an outwardly narrowing inner hole at each end. The guide cone ring located at the medium inlet end has its narrowed inner hole extending to the area where the air-water premixing nozzle and the asphalt nozzle are located, smoothly guiding the high-speed jet into the mixing zone in the middle of the cavity, reducing impact and energy loss. The guide cone ring located at the foamed asphalt outlet end has its narrowed inner hole extending to the port of the outlet pipe, smoothly collecting and discharging the generated foamed asphalt, preventing eddies or accumulation at the outlet.

[0014] Preferably, the transmission structure is a gear ring fixedly fitted onto the outer wall of the foaming chamber, and the driving device includes a drive gear for synchronously meshing with two adjacent sets of gear rings. One drive gear can drive two adjacent foaming units simultaneously, resulting in a simple and efficient transmission structure. Furthermore, the foaming chamber is suspended and rotatably supported above the base frame by a support frame mounted outside the multilayer medium pipe and the outlet pipe, ensuring stable operation.

[0015] Furthermore, the equipment also includes a multi-way distribution pipe assembly, comprising an asphalt main pipe connected to the outlet of the asphalt pump, an air main pipe connected to an air source, and a water main pipe connected to a water pump. The asphalt main pipe, air main pipe, and water main pipe are each connected to a corresponding foaming unit via multiple branch pipes independently controlled by solenoid valves. This design allows for independent control of the feed to each foaming unit, enabling capacity adjustment and online maintenance.

[0016] Based on the above-mentioned equipment, the present invention also provides a method for foaming asphalt, comprising the following steps: S1: Prefabricate the thermal displacement guide mechanism, the pump unit mounting base plate with vibration damping pads, and the foaming module in the factory; S2: At the construction site, install the prefabricated thermal displacement guiding mechanism, the rigid base plate for pump unit installation, and the foaming module onto the base frame. S3: Install the heated storage tank on the thermal displacement guide mechanism and fix the asphalt pump on the pump set mounting base plate; S4: Connect the multi-way distribution pipe group to connect the asphalt pump, water source, air source and each foaming unit; S5: Start the equipment and distribute and deliver high-temperature asphalt, foaming water, and compressed air to the parallel-arranged rotary foaming units via a multi-way distribution pipe assembly. Within each rotary foaming unit, water and compressed air are pre-mixed and atomized at the air-water premixing nozzle to form an air-water mixed mist. This air-water mixed mist is then mixed and foamed with the asphalt jet ejected from the asphalt nozzle within a foaming chamber rotating around its own axis. The resulting foamed asphalt is discharged from the outlet pipe.

[0017] As a further optimization of this method, during the foaming process in step S5, the supply of asphalt to any designated foaming unit can be cut off by controlling the solenoid valve, while maintaining the water and air supply and the rotation of the foaming cavity in that unit. At this time, high-speed air and clean water can flush the inside of the cavity, realizing online rotational cleaning of a single foaming unit, while other units can continue normal production, achieving maintenance without stopping the machine.

[0018] The beneficial effects of this invention are: 1 In this invention, core functional components, such as the thermal displacement guiding mechanism, the rigid base plate for pump assembly, and the foaming module, are prefabricated in the factory. On-site assembly and connection with the base frame is only required, which greatly shortens the construction period and ensures assembly accuracy. 2. In this invention, the specially designed thermal displacement guiding mechanism can effectively absorb and release the thermal stress of the storage tank and avoid structural damage; the integral rigid base plate of the pump unit, together with the vibration damping pads, effectively isolates the transmission of vibration to the foaming module, thereby improving the overall stability of the system and the service life of the equipment. 3 In this invention, the foaming module is composed of multiple independent, side-by-side foaming units. The production capacity can be linearly adjusted by simply increasing or decreasing the number of units. The initial investment is low, and subsequent expansion is convenient and economical. 4 In this invention, the rotating foaming cavity, the internal spiral guide ribs, the double-layer nozzle layout surrounding the asphalt expansion design with air and water nozzles, and the coordinated design of the guide cone rings at both ends ensure that the material undergoes strong shearing, is fully mixed and smoothly discharged, and the resulting foamed asphalt is uniform, delicate and stable. 5. In this invention, the multi-way distribution pipe group is combined with independent solenoid valve control, so that any foaming unit can independently perform online water and air rotation cleaning and maintenance without stopping the machine, which greatly improves equipment utilization and production continuity. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the structure of the bottom side fixing block and multiple sets of radial guide blocks of the heating storage tank arranged in a matrix shape. Figure 2This is a breakdown diagram of the axial guide rail, radial guide block, and axial guide block; Figure 3 This is a structural cross-sectional view of a set of foaming units; Figure 4 This is a schematic diagram of the transmission connection between two adjacent sets of foaming units; Markings in the diagram: 100. Heating storage tank; 200. Base frame; 300. Support frame; 10. Fixing block; 20. Axial guide rail; 30. Radial guide block; 40. Axial guide block; 41. Radial guide groove; 50. Multi-layer medium pipe; 51. Asphalt flow channel; 52. Water flow channel; 53. Air flow channel; 60. Foaming cavity; 54. Asphalt nozzle; 55. Air-water premixed nozzle; 61. Spiral guide rib; 62. Guide cone ring; 70. Outlet pipe; 81. Gear ring; 82. Drive gear; 83. Drive shaft. Detailed Implementation

[0020] Example 1 like Figures 1 to 4 As shown, this embodiment provides a standard foamed asphalt foaming equipment.

[0021] The equipment includes a horizontally extending cylindrical heating tank 100, an asphalt pump, a foaming module, and a horizontal base frame 200. The asphalt pump is located between the heating tank and the foaming module, and its inlet is connected to the bottom outlet of the heating tank 100 via an insulated pipeline, for pumping out high-temperature asphalt at approximately 160℃-180℃.

[0022] Installation of the heating storage tank 100: The heating storage tank 100 is installed at the front of the base frame 200 via a thermal displacement guiding mechanism. For example... Figure 1 and Figure 2 As shown, the mechanism includes one positioning unit and five guiding units. The positioning unit is a fixed block 10 fastened to the bottom of the heating tank 100 and the base frame 200 by high-strength bolts, located at one end corner along the length of the heating tank 100, used to determine the installation reference. The five guiding units are arranged in a matrix with the fixed block 10. Each guiding unit includes: an axial guide rail 20 fixed to the base frame 200, a radial guide block 30 fixed to the bottom of the tank, and an axial guide block 40. The lower part of the axial guide block 40 is slidably engaged with the axial guide rail 20, allowing it to slide along the direction of the axial guide rail 20 (i.e., the axial direction of the heating tank 100). The upper part of the axial guide block 40 is machined with a radial guide groove 41, into which the radial guide block 30 is embedded and can slide, with the sliding direction perpendicular to the axial guide rail 20. When the heated storage tank 100 expands due to heat, one end of it can slide along the axial guide rail 20 to the outside of the fixed block 10. At the same time, the radial expansion is compensated by the sliding of the radial guide block 30 in the radial guide groove 41, thereby completely releasing the thermal stress.

[0023] Installation of the asphalt pump: The asphalt pump is fixedly mounted on a rigid, integral base plate made of 30mm thick Q235 steel plate. A rubber vibration damping pad is installed at each of the four corners of this rigid base plate. The entire pump unit, via this base plate and vibration damping pads, sits in the center of the base frame 200, achieving vibration isolation.

[0024] Structure and installation of the foaming module: The foaming module is installed at the rear of the base frame 200 and consists of two foaming units arranged side by side with identical structures.

[0025] like Figure 3 As shown, each foaming unit includes: A fixed multi-layer medium tube 50 is made up of three concentric stainless steel tubes, forming a central asphalt channel 51, a middle water channel 52, and an outermost air channel 53. The stainless steel tubes can be spaced apart by a middle partition to improve the stability of the space.

[0026] A cylindrical foaming cavity 60 is rotatably fitted outside the multi-layer media pipe, with one end serving as the media inlet and the other as the foamed asphalt outlet. The tail end of the multi-layer media pipe extends into the foaming cavity 60 through the media inlet. The outlets of the air channel 53 and the water channel 52 merge to form an annular air-water premixed nozzle 55; the outlet of the asphalt channel 51 forms a conical asphalt nozzle 54. The asphalt nozzle 54 is flared, and the annular seam of the air-water premixed nozzle 55 is located precisely on the outer wall of this flared section, allowing the atomized air and water to surround the asphalt jet.

[0027] A spiral guide rib 61 with the same direction of rotation and a lead twice the length of the cavity is welded to the inner wall of the cavity 60. Guide cone rings 62 are also provided on the inner walls of both ends of the cavity 60. The large opening of the cone ring 62 at the inlet end faces the nozzle area and is used to guide the jet; the large opening of the cone ring 62 at the outlet end is connected to an outlet pipe 70 for discharging foam.

[0028] like Figure 4 As shown, a gear ring 81 is fixed to the outer wall of the foaming chamber 60. A drive gear 82 driven by a variable frequency motor meshes with the gear rings 81 of both foaming units simultaneously, thereby synchronously driving them to rotate at a speed of 20-50 rpm. The entire foaming chamber 60 is suspended on the base frame by a gantry-type support frame 300.

[0029] Control system: The equipment is also equipped with a multi-way distribution pipe assembly, including an asphalt main pipe, an air main pipe, and a water main pipe. Each main pipe is connected to the corresponding flow channel of two foaming units through branch pipes, and each branch pipe is equipped with a solenoid valve. All solenoid valves and drive motors are controlled by a PLC central controller.

[0030] Workflow: Upon starting the equipment, the PLC controls the activation of all feed solenoid valves and rotary drives for both foaming units. High-temperature asphalt, room-temperature water, and compressed air enter their respective flow channels in a set ratio. Inside the foaming unit, water and air are atomized and mixed at the air-water premixing nozzle 55, subsequently enveloping the asphalt jet ejected from the central asphalt nozzle 54. The mixture flows into the high-speed rotating cavity 60, where it is fully mixed and foamed under the strong shearing and axial pushing of the spiral guide ribs 61, forming uniform foamed asphalt, which is then discharged through the outlet pipe 70. If cleaning of Unit 1 is required, the PLC can close its asphalt branch pipe solenoid valve while maintaining water and air supply and rotation, thus achieving online cleaning. Unit 2 continues normal production.

[0031] Example 2 The main difference between this embodiment and Embodiment 1 lies in the capacity expansion configuration of the foaming module, demonstrating the flexible and adjustable capacity of the present invention.

[0032] In this embodiment, the base frame of the equipment is lengthened accordingly to accommodate more foaming units. The capacity of the heating tank and the flow rate of the asphalt pump are also increased accordingly, and the installation method (thermal displacement guiding mechanism, vibration damping installation) is the same as in Embodiment 1.

[0033] The foaming module has been changed to include three foaming units arranged side by side with identical structures. The internal structure of these three foaming units is completely consistent with that described in Embodiment 1.

[0034] Drive method: In the three foaming units, two adjacent foaming units share a drive gear for synchronous drive, that is, they use a drive motor and two drive gears. The drive motor can be connected to any set of drive shafts 83 that drive the drive gears to rotate.

[0035] The above description is merely 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 foaming device for foamed asphalt, comprising a heated storage tank, an asphalt pump, a foaming module, and a base frame, wherein the asphalt pump is located between the heated storage tank and the foaming module, and is used to transport asphalt from the heated storage tank to the foaming module, characterized in that: The heating tank is mounted on the base frame via a thermal displacement guiding mechanism, which allows the heating tank to thermally expand along its axial and radial directions. The asphalt pump is fixedly installed on an integral rigid base plate, which is mounted on the base frame by vibration damping pads; The foaming module is mounted on the base frame and includes at least two foaming units arranged side by side with identical structures. Each foaming unit includes a rotatable foaming cavity.

2. The foaming equipment for foamed asphalt according to claim 1, characterized in that, The thermal displacement guiding mechanism includes a set of positioning units and multiple sets of guiding units arranged in a matrix. The positioning unit includes a set of fixing blocks that are locked between the base frame and the heated storage tank by a first screw; The guide unit includes an axial guide rail fixed to the base frame by a second screw, a radial guide block fixedly installed at the bottom of the heating tank, and an axial guide block connected between the radial guide block and the axial guide rail. The axial guide block is slidably installed in the axial guide rail and has a radial guide groove on it. The radial guide block is guided and installed in the radial guide groove. All axial guide rails extend in the same direction as the axial extension of the heating tank, and all radial guide grooves extend in a direction perpendicular to the axial extension of the heating tank.

3. The foaming equipment for foamed asphalt according to claim 1, characterized in that, The foaming unit includes: A fixed multi-layer medium tube has three coaxially arranged independent flow channels inside, which are, from the inside to the outside, an asphalt flow channel, a water flow channel, and an air flow channel. A cylindrical foaming cavity is rotatably fitted outside the multi-layer media pipe, with one end being the media inlet and the other end being the foamed asphalt outlet. The tail end of the multi-layer media pipe extends into the foaming cavity through the media inlet, and its outermost flow channel and the outlet of the middle flow channel converge and connect to form an air-water premixed nozzle; the outlet of its innermost flow channel forms an asphalt nozzle. The foamed asphalt outlet end is also connected to an outlet pipe, which is coaxially arranged with the multi-layer medium pipe. A transmission structure disposed on the outer periphery of the foaming cavity, and a driving device drivenly connected to the transmission structure, for driving the foaming cavity to rotate around the axis of the multilayer medium pipe and the outlet pipe.

4. The foaming equipment for foamed asphalt according to claim 3, characterized in that, The asphalt nozzle is flared outwards toward the foaming cavity, and the ejection end of the air-water premixed nozzle is located on the outer wall of the flared section of the asphalt nozzle.

5. The foaming equipment for foamed asphalt according to claim 3, characterized in that, The inner wall of the foaming cavity is provided with at least one spiral guide rib extending from the medium inlet end to the foamed asphalt outlet end.

6. The foaming equipment for foamed asphalt according to claim 3, characterized in that, The inner wall of the foaming cavity is provided with a guide cone ring with an outwardly narrowed inner hole at each end; wherein, the guide cone ring located at the medium inlet end has its narrowed inner hole extending to the area where the air-water premix nozzle and the asphalt nozzle are located; the guide cone ring located at the foamed asphalt outlet end has its narrowed inner hole extending to the port of the outlet pipe.

7. The foaming equipment for foamed asphalt according to claim 3, characterized in that, The transmission structure is a gear ring fixedly fitted on the outer wall of the foaming cavity. The driving device includes a driving gear for synchronously meshing with two adjacent sets of gear rings. The foaming cavity is suspended and rotatably supported above the base frame by a support frame mounted outside the multi-layer medium pipe and the outlet pipe.

8. The foaming equipment for foamed asphalt according to any one of claims 1 to 7, characterized in that, It also includes a multi-way distribution pipe group, which includes an asphalt main pipe connected to the outlet end of the asphalt pump, an air main pipe connected to the air source, and a water quality main pipe connected to the water pump. The asphalt main pipe, air main pipe, and water quality main pipe are respectively connected to the corresponding foaming unit through multiple branch pipes that are independently controlled to open and close by solenoid valves.

9. A method for foaming asphalt, using the foaming equipment for foamed asphalt as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1: Prefabricate the thermal displacement guide mechanism, the pump unit mounting base plate with vibration damping pads, and the foaming module in the factory; S2: At the construction site, the thermal displacement guiding mechanism, the rigid base plate for pump unit installation, and the foaming module are installed on the base frame; S3: Install the heated storage tank on the thermal displacement guide mechanism and fix the asphalt pump on the pump set mounting base plate; S4: Connects to a multi-way distribution pipe group; S5: Start the equipment and distribute and transport high-temperature asphalt, foaming water and compressed air through a multi-way distribution pipe group to the rotating foaming units arranged in parallel. In each of the rotating foaming units, water and compressed air are pre-mixed and atomized at a gas-water premixing nozzle to form a gas-water mixed mist. The gas-water mixed mist is mixed and foamed with the asphalt jet sprayed from the asphalt nozzle in a foaming cavity that rotates around its own axis. The generated foamed asphalt is discharged from the outlet pipe.

10. The foaming method for asphalt according to claim 9, characterized in that, In step S5, the foaming unit is cleaned online by cutting off the asphalt supply to any of the foaming units while maintaining its water and air supply and the rotation of the foaming cavity.

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