A modified asphalt fluidity detection device

Abstract

This invention relates to the field of new material testing technology, and more particularly to a modified asphalt flowability testing device. It includes a base, a gantry frame, a testing barrel, and a lifting seat driven by a lifting cylinder. The lifting seat contains a coaxial reversing mechanism composed of an upper bevel gear, a side bevel gear, and a lower bevel gear. A rotary motor drives the upper bevel gear and the pumping shaft to rotate, which in turn drives the hollow rotating shaft to rotate in the opposite direction via the coaxial reversing mechanism. A centrifugal impeller is installed at the bottom of the pumping shaft, and a hollow rotor with a double-helix guide groove is connected to the bottom of the hollow rotating shaft. The centrifugal impeller draws asphalt from the bottom into the hollow connecting shaft and discharges it through a drain hole, guiding it to the double-helix guide groove by a guide shroud, forming an axial forced circulation flow field. Simultaneously, a rotating ring and turbulence fins driven by a second rotary motor are located at the bottom of the lifting seat, rotating differentially in the opposite direction to the hollow rotor, generating staggered shearing and radial turbulence. This invention effectively overcomes the shortcomings of existing testing devices, such as a single flow field and insufficient shear simulation.

Description

Technical Field

[0001] This invention relates to the field of new material testing technology, and in particular to a device for testing the fluidity of modified asphalt. Background Technology

[0002] Modified asphalt is made by adding modifiers to base asphalt, and its rheological properties directly affect the workability and service performance of pavements. Accurately assessing the fluidity of modified asphalt under shear, pumping, and mixing conditions is crucial in laboratory studies and engineering quality control.

[0003] Existing asphalt fluidity testing devices mostly employ rotational viscometers or simple blade agitation. However, these traditional devices have significant drawbacks: firstly, they present a single flow field, failing to simulate the forced axial circulation flow experienced by asphalt in actual pumping pipelines or mixing tanks; secondly, their shearing effect is weak, making it difficult to effectively evaluate the dispersion uniformity and viscosity changes of modified asphalt under dynamic shear. Summary of the Invention

[0004] The present invention aims to solve the technical problems of the existing technology, such as the single detection flow field and insufficient shear simulation, and provides a modified asphalt fluidity testing device that can form an axial forced circulating flow field and generate differential turbulence.

[0005] The technical solution adopted in this invention is: a modified asphalt fluidity testing device, comprising a base. A gantry frame and a testing bucket for holding the asphalt to be tested are mounted on the base. A lifting cylinder is installed on the top of the gantry frame, and the output end of the lifting cylinder is connected to a lifting seat. A transmission cavity is formed inside the lifting seat, and a coaxial reversing mechanism is configured within the transmission cavity. The coaxial reversing mechanism includes an upper bevel gear, a side bevel gear, and a lower bevel gear; the side bevel gear is rotatably disposed on the side wall of the transmission cavity, and the lower bevel gear is rotatably disposed at the bottom of the transmission cavity; the upper and lower bevel gears are respectively meshed with the side bevel gear, so that the rotation directions of the upper and lower bevel gears are opposite.

[0006] A rotary motor is mounted on the top of the lifting platform, and its output end is coaxially and fixedly connected to the upper bevel gear. A pumping shaft extending downwards is coaxially fixed to the upper bevel gear. An axial through hole is provided inside the lower bevel gear, through which the pumping shaft passes and can rotate freely. A hollow rotating shaft is coaxially and fixedly connected to the bottom of the lower bevel gear, and the pumping shaft and the hollow rotating shaft form a coaxial reversing structure.

[0007] A centrifugal impeller is installed at the bottom end of the pumping shaft. A hollow connecting shaft is installed at the bottom end of the hollow rotating shaft, and the centrifugal impeller is located in the inner cavity of the hollow connecting shaft. A drain hole is opened on the upper side wall of the hollow connecting shaft, and a liquid inlet is opened at the bottom of the hollow connecting shaft. A hollow rotor is fixedly sleeved or integrally formed on the bottom outer wall of the hollow connecting shaft. A double helical guide groove is machined on the outer wall of the hollow rotor. A guide shroud is also fixed on the outer wall of the hollow connecting shaft. The outlet end of the guide shroud points to the double helical guide groove on the outer wall of the hollow rotor, which is used to guide the asphalt liquid discharged from the drain hole to the double helical guide groove.

[0008] A mounting plate is fixedly connected to the bottom of the lifting seat. A through hole is formed in the center of the mounting plate, and a bevel gear is rotatably mounted within this hole. A second rotary motor is also fixedly mounted on the mounting plate. The output end of the second rotary motor is connected to another bevel gear, which meshes with the first bevel gear. At least three connecting rods are fixedly connected to the bottom of the first bevel gear, and a rotating ring is fixed to the bottom of each connecting rod. Several circumferentially distributed turbulence fins are provided on the inner wall of the rotating ring.

[0009] In operation, the rotation of the hollow shaft drives the hollow connecting shaft and the hollow rotor to rotate synchronously; simultaneously, the pumping shaft rotates in the opposite direction relative to the hollow shaft under the drive of the first rotary motor. The centrifugal impeller draws the asphalt from the bottom of the testing tank into the inner cavity of the hollow connecting shaft through the inlet and pumps it upwards until it is discharged from the drain hole. The discharged asphalt is guided by the guide shroud to the double helical guide groove on the outer wall of the hollow rotor, and flows back along the two helical grooves with opposite directions from top to bottom to the bottom of the hollow rotor, thus forming an axial forced circulation flow field inside the testing tank. At the same time, the rotating ring and the turbulence fins on its inner side rotate in opposite directions relative to the hollow rotor, generating staggered shear and radial turbulence around the rotor.

[0010] Furthermore, both the leading and trailing edges of the turbulence fins adopt a circular arc transition structure. The turbulence fins are uniformly distributed along the circumference of the rotating ring, and their inner edges extend towards the hollow rotor to optimize the distribution of the shear flow field.

[0011] Furthermore, a torque sensor is installed on the hollow shaft, which is fixed to the bottom of the transmission cavity to monitor the asphalt viscosity resistance experienced by the hollow shaft during rotation in real time.

[0012] Furthermore, a clamping motor is installed at the lower end of the vertical column of the gantry frame. The output end of the clamping motor is connected to a clamping screw, and guide rods are arranged parallel to each other on the upper and lower sides of the clamping screw. The two ends of the guide rods are fixed to the vertical column of the gantry frame. Two symmetrically arranged moving blocks are threaded onto the clamping screw, and the threads of the two moving blocks and the clamping screw have opposite directions of rotation. The moving blocks pass through the guide rods to provide guidance. Symmetrical clamping rings are fixed to each of the two moving blocks for clamping and fixing the testing barrel.

[0013] Furthermore, guide grooves are provided on the inner walls of both sides of the upper end of the vertical column of the gantry frame. Fixed rods are fixed on both sides of the lifting seat, and guide wheels are rotatably connected to the ends of the fixed rods. The guide wheels slide in the guide grooves to ensure the smoothness of the lifting seat's up and down movement.

[0014] Furthermore, a sealed bearing is provided between the bottom of the hollow rotating shaft and the pumping shaft to prevent asphalt liquid from flowing back into the transmission cavity.

[0015] Furthermore, the bottom of the hollow rotating shaft is provided with an external thread, and the top of the hollow connecting shaft is provided with an internal thread. The two are connected by threaded engagement, which facilitates disassembly and cleaning.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. By incorporating a coaxial reversing mechanism consisting of an upper bevel gear, a side bevel gear, and a lower bevel gear within the lifting base, and coaxial reversing structures of the hollow rotating shaft and the pumping shaft, reverse synchronous drive of the centrifugal impeller and the hollow rotor is achieved. The centrifugal impeller draws asphalt from the bottom of the testing tank into the inner cavity of the hollow connecting shaft through the inlet and pumps it upwards to the drain hole. The discharged asphalt, constrained by the guide shroud, enters the double-helix guide groove on the outer wall of the hollow rotor, flowing back down along the two helical grooves in opposite directions to the bottom of the hollow rotor, thus creating an axial forced circulation flow field within the testing tank. This forced circulation effectively avoids localized sedimentation and component stratification of the asphalt in traditional testing, ensuring that the sample remains in a uniformly mixed state, significantly improving the consistency between the test results and actual working conditions.

[0017] 2. A rotating motor drives the rotating ring and inner turbulence fins to rotate at a different speed in the opposite direction relative to the hollow rotor. The arc transition design of the leading and trailing edges of the turbulence fins optimizes the flow field distribution within the annular shear gap, generating strong interlaced shear and radial turbulence around the rotor. This composite shear of external turbulence and internal spiral backflow can more realistically simulate the stress history of modified asphalt in a mixing tank or conveying pipeline, thereby accurately evaluating its dispersion stability and rheological properties under high shear dynamic environments. Attached Figure Description

[0018] 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 present invention; Figure 2 This is a schematic diagram of the structure of the lifting seat; Figure 3 This is a schematic diagram of the structure at the hollow rotor. Figure 4 This is a schematic diagram of the internal structure of the hollow rotor, hollow shaft, and hollow connecting shaft. Figure 5 This is a structural diagram of the gantry frame. Figure 6 This is a schematic diagram of the connection between the hollow rotating shaft and the hollow connecting shaft.

[0019] In the diagram: 1-Base; 2-Gantry frame; 3-Detection barrel; 4-Lifting cylinder; 5-Lifting seat; 6-Transmission chamber; 7-Upper bevel gear; 8-Side bevel gear; 9-Lower bevel gear; 10-Rotary motor one; 11-Pumping shaft; 12-Hollow rotating shaft; 13-Torque sensor; 14-Centrifugal impeller; 15-Hollow connecting shaft; 16-Drain hole; 17-Inlet; 18-Hollow rotor; 19-Double spiral guide channel; 20-Guide cover; 21-Mounting plate; 22-Bevel gear one; 23-Rotary motor two; 24-Bevel gear two; 25-Connecting rod; 26-Rotating ring; 27-Turbulence fins; 28-Sealed bearing; 29-Guide groove; 30-Fixing rod; 31-Guide wheel; 32-Clamping motor; 33-Clamping screw; 34-Moving block; 35-Clamping ring; 36-Guide rod. Detailed Implementation

[0020] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0021] As shown in the figure, a modified asphalt fluidity testing device includes a stable base 1. A gantry frame 2 is erected on the base 1, and a testing bucket 3 for loading modified asphalt samples is placed in the central area of ​​the base 1. A lifting cylinder 4 is fixedly installed at the center of the top of the crossbeam of the gantry frame 2. The piston rod of the lifting cylinder 4 passes downward through the crossbeam and is fixedly connected to a lifting seat 5. To ensure the stability of the lifting seat 5 in the vertical direction, a guide groove 29 is provided on the inner side of the upper end of the vertical column of the gantry frame 2. Guide wheels 31 are installed at the ends of the fixed rods 30 extending from both sides of the lifting seat 5. The guide wheels 31 can roll and fit into the guide groove 29.

[0022] The lifting seat 5 has a hollow transmission cavity 6 machined inside. A coaxial reversing mechanism is installed inside the transmission cavity 6, specifically consisting of a set of bevel gears: a side bevel gear 8 is rotatably connected to the side wall of the transmission cavity 6 via bearings, and an upper bevel gear 7 and a lower bevel gear 9 are located on the upper and lower sides of the side bevel gear 8 respectively and mesh with it simultaneously. Therefore, when the upper bevel gear 7 rotates, through the transmission of the side bevel gear 8, the lower bevel gear 9 will obtain a rotation in the opposite direction to that of the upper bevel gear 7.

[0023] A rotary motor 10 is mounted on the top of the lifting seat 5, and its output shaft extends into the transmission cavity 6 and is fixedly connected to the axle of the upper bevel gear 7. A slender pumping shaft 11 is coaxially fixed to the lower end face of the upper bevel gear 7. An axial through hole is opened in the center of the lower bevel gear 9, through which the pumping shaft 11 passes, with a rotational clearance between them to prevent interference. A hollow rotating shaft 12 is coaxially fixed to the bottom of the lower bevel gear 9, and the hollow rotating shaft 12 is sleeved on the outside of the pumping shaft 11. A sealed bearing 28 is also installed between the bottom of the hollow rotating shaft 12 and the pumping shaft 11, which ensures smooth relative rotation and provides a sealing and leak-proof function. In addition, in order to collect torque data in real time, a torque sensor 13 is sleeved on the shaft of the hollow rotating shaft 12, and the stator of the torque sensor 13 is fixed to the bottom of the transmission cavity 6.

[0024] A centrifugal impeller 14 is mounted at the bottom end of the pumping shaft 11. A hollow connecting shaft 15 is detachably connected to the bottom end of the hollow rotating shaft 12 via a threaded structure (or flange structure). The centrifugal impeller 14 is completely housed within the bottom of the inner cavity of the hollow connecting shaft 15. Multiple drainage holes 16 are circumferentially opened on the upper side wall of the hollow connecting shaft 15, while its bottom end face is completely open as a liquid inlet 17.

[0025] A hollow rotor 18 is integrally connected to the lower half of the outer wall of the hollow connecting shaft 15. A double-helix guide groove 19 is formed on the outer wall of the hollow rotor 18, consisting of two helical grooves with opposite directions of rotation. A funnel-shaped or umbrella-shaped guide shroud 20 is fixedly connected to the middle of the outer wall of the hollow connecting shaft 15. The lower edge of the guide shroud 20 is aligned with the starting point of the double-helix guide groove 19 on the upper part of the hollow rotor 18.

[0026] A mounting plate 21 is bolted to the bottom of the lifting seat 5. A bevel gear 22 is rotatably mounted in the central opening of the mounting plate 21 via a bearing. A rotary motor 23 is mounted on the upper side of the mounting plate 21, and a bevel gear 24 mounted on its output end meshes with the bevel gear 22 for transmission. Three or four connecting rods 25 are evenly welded to the bottom of the bevel gear 22, and the bottom ends of the connecting rods 25 are connected to a rotating ring 26. The inner diameter of the rotating ring 26 is larger than the outer diameter of the hollow rotor 18, so that an annular shear gap is formed between them. Several turbulence fins 27 are integrally formed on the inner sidewall of the rotating ring 26. The leading and trailing edges of these turbulence fins 27 are rounded to reduce local dead zone eddies, and their inner edges extend toward the hollow rotor 18, getting as close as possible to the rotor surface.

[0027] To secure the testing barrel 3, a clamping motor 32 is installed on the lower side of the vertical column of the gantry 2. The clamping motor 32 drives the clamping screw 33 to rotate. The clamping screw 33 is a bidirectional screw, with the threads of the left and right halves rotating in opposite directions. Two moving blocks 34 are symmetrically mounted on the clamping screw 33, and the internal threads of the moving blocks 34 engage with the screw. To ensure that the moving blocks 34 do not rotate with the screw, two guide rods 36 pass through the holes on the moving blocks 34. When the clamping motor 32 rotates, the two moving blocks 34 move towards or away from each other under the constraint of the guide rods 36. Each moving block 34 is fixed with a semi-circular clamping ring 35. The two clamping rings 35 engage to firmly clamp the testing barrel 3, preventing it from shaking during the testing process.

[0028] Working principle: During testing, the clamping motor 32 is first started to securely clamp the test bucket 3 containing modified asphalt. Then, the lifting cylinder 4 is started to push the lifting seat 5 down, so that the hollow rotor 18, the rotating ring 26 and the centrifugal impeller 14 are submerged below the asphalt liquid surface of the test bucket 3.

[0029] When the rotary motor 10 is started, the upper bevel gear 7 drives the pumping shaft 11 to rotate at high speed. The centrifugal impeller 14 generates negative pressure inside the hollow connecting shaft 15, drawing the asphalt from the bottom of the tank through the inlet 17 and pumping it upwards. Simultaneously, the power of the rotary motor 10 is transmitted through the coaxial reversing mechanism, causing the lower bevel gear 9 and the hollow rotating shaft 12 to rotate in opposite directions. The hollow rotating shaft 12 drives the hollow connecting shaft 15 and the hollow rotor 18 to rotate synchronously in opposite directions.

[0030] The asphalt pumped up by the centrifugal impeller 14 is discharged from the drain hole 16 and precisely guided by the guide shroud 20 to the top inlet of the double helical guide groove 19 on the outer wall of the hollow rotor 18. Subsequently, under the combined action of gravity and centrifugal force, the asphalt flows from top to bottom along the two helical groove paths with opposite directions, finally flowing out from the bottom of the hollow rotor 18 and returning to the bottom of the test tank 3.

[0031] At the same time, the second rotary motor 23 is started, driving the rotating ring 26 and the turbulence fins 27 to rotate in the opposite direction to the hollow rotor 18 via bevel gear transmission. This reverse differential motion generates extremely strong shear rates and turbulent disturbances within the annular gap, greatly enhancing the dispersion effect of particles inside the modified asphalt.

[0032] By reading the torque value of the hollow shaft 12 in real time by the torque sensor 13, the asphalt flowability parameters under the specific flow field conditions can be calculated.

Claims

1. A modified asphalt fluidity testing device, comprising a base (1), characterized in that: The base (1) is provided with a gantry frame (2) and a detection barrel (3). The top of the gantry frame (2) is provided with a lifting cylinder (4). The output end of the lifting cylinder (4) is provided with a lifting seat (5). The lifting seat (5) is provided with a transmission cavity (6). The transmission cavity (6) is provided with a coaxial reversing mechanism. The coaxial reversing mechanism includes an upper bevel gear (7), a side bevel gear (8) and a lower bevel gear (9). The side bevel gear (8) is rotatably disposed on the side wall of the transmission cavity (6). The lower bevel gear (9) is rotatably disposed at the bottom of the transmission cavity (6). The upper bevel gear (7) and the lower bevel gear (9) are respectively meshed with the side bevel gear (8), so that the upper bevel gear (7) and the lower bevel gear (9) rotate in opposite directions. The top of the lifting seat (5) is provided with a rotary motor (10), the output end of the rotary motor (10) is coaxially fixedly connected to the upper bevel gear (7), and a pumping shaft (11) is coaxially provided on the upper bevel gear (7); the lower bevel gear (9) is provided with an axial through hole, and the pumping shaft (11) passes through the axial through hole of the lower bevel gear (9) and extends downward; a hollow rotating shaft (12) is coaxially provided at the bottom of the lower bevel gear (9), and the pumping shaft (11) and the hollow rotating shaft (12) form a coaxial reversing structure; A centrifugal impeller (14) is provided at the bottom of the pumping shaft (11), and a hollow connecting shaft (15) is provided at the bottom of the hollow rotating shaft (12). The centrifugal impeller (14) is located inside the hollow connecting shaft (15). A drain hole (16) is provided on the upper side wall of the hollow connecting shaft (15), and the bottom of the hollow connecting shaft (15) is a liquid inlet (17). A hollow rotor (18) is provided on the bottom outer wall of the hollow connecting shaft (15), and a double spiral guide groove (19) is provided on the outer wall of the hollow rotor (18). A guide shroud (20) is provided on the outer wall of the hollow connecting shaft (15). The guide shroud (20) is used to guide the asphalt discharged from the drain hole (16) to the double spiral guide groove (19) on the outer wall of the hollow rotor (18). The bottom of the lifting seat (5) is provided with an installation plate (21). The middle of the installation plate (21) is provided with a through hole. A bevel gear (22) is rotatably installed in the through hole. A rotary motor (23) is provided on the installation plate (21). A bevel gear (24) is provided at the output end of the rotary motor (23). The bevel gear (24) meshes with the bevel gear (22). At least three connecting rods (25) are provided at the bottom of the bevel gear (22). A rotating ring (26) is provided at the bottom of the connecting rods (25). Several circumferentially distributed turbulence fins (27) are provided on the rotating ring (26).

2. The modified asphalt fluidity testing device according to claim 1, characterized in that: The leading and trailing edges of the turbulence fins (27) are both arc transitions. The turbulence fins (27) are evenly distributed along the circumference of the rotating ring (26), and their inner edges extend toward the hollow rotor (18).

3. The modified asphalt fluidity testing device according to claim 1, characterized in that: A torque sensor (13) is provided on the hollow rotating shaft (12), and the torque sensor (13) is fixed to the bottom of the transmission cavity (6).

4. The modified asphalt fluidity testing device according to claim 1, characterized in that: A clamping motor (32) is provided at the lower end of the vertical column of the gantry frame (2). A clamping screw (33) is provided at the output end of the clamping motor (32). Guide rods (36) are provided on the upper and lower sides of the clamping screw (33). The two ends of the guide rods (36) are fixed on the vertical column of the gantry frame (2). Two symmetrically arranged moving blocks (34) are threaded on the clamping screw (33). The two moving blocks (34) are threaded in opposite directions to the clamping screw (33), and the moving blocks (34) pass through the guide rods (36). Symmetrical clamping rings (35) are provided on the two moving blocks (34). The clamping rings (35) are used to clamp and fix the detection barrel (3).

5. The modified asphalt fluidity testing device according to claim 1, characterized in that: The upper end of the vertical column of the gantry (2) is provided with guide grooves (29) on both sides of the inner wall. The lifting seat (5) is provided with fixed rods (30) on both sides. The fixed rods (30) are provided with guide wheels (31) that are rotatably connected at the end of the fixed rods (30). The guide wheels (31) are slidably connected in the guide grooves (29).

6. The modified asphalt fluidity testing device according to claim 1, characterized in that: A sealed bearing (28) is provided between the bottom of the hollow rotating shaft (12) and the pumping shaft (11).

7. The modified asphalt fluidity testing device according to claim 1, characterized in that: The hollow shaft (12) has an external thread at its bottom and the hollow connecting shaft (15) has an internal thread at its top. The hollow connecting shaft (15) and the hollow shaft (12) are connected by threads.

Images