A laboratory RAP sample pretreatment, purification and drying device

Abstract

The application provides a laboratory RAP sample pretreatment, purification and drying device, which comprises a washing and desilting area, a low-temperature drying area and a discharge valve connected with the two areas; the washing and desilting area comprises a washing cylinder, a discharge port, a stirrer, an overflow assembly and an overflow port. In the application, the washing cylinder serves as a bearing container, the stirrer disturbs RAP and water, the vertically-slidable overflow assembly can adjust the relative height on the side wall according to the sample characteristics, and then the washing water level is dynamically set; for impurities with different densities, the overflow horizon is adjusted, the surface sewage discharge or the bottom impurity suspension effect is optimized, the discharge valve is opened after washing, the material enters the low-temperature drying area through the discharge port, and since the water level is regulated in the previous stage, the water content of the sample is optimized, so that the drying cycle is shortened and the overall experimental efficiency is improved in the low-temperature environment defined by the specification.

Description

Technical Field

[0001] This utility model relates to the technical field of waste asphalt mixtures, and in particular to a laboratory RAP sample pretreatment purification and drying device. Background Technology

[0002] Against the backdrop of my country's highway network transitioning from a "construction-oriented" to a "construction and maintenance-equal" approach, the recycling of reclaimed asphalt pavement (RAP) has become a crucial link in achieving green transportation and resource recycling. According to the current industry standard JTG / T5521-2019 "Technical Specification for Highway Asphalt Pavement Recycling," the performance indicators of aged asphalt must be accurately tested before RAP can be recycled. The accuracy of the test data is highly dependent on the cleanliness of the RAP sample pretreatment.

[0003] Currently, laboratory treatment of RAP often employs a rudimentary approach combining simple rinsing with oven drying. In this process, the overflow structure is typically fixed, a design that presents significant limitations when dealing with RAP samples of complex origins and varying properties, directly hindering experimental progress. Because the overflow height is not adjustable, the rinsing process cannot be precisely controlled according to the actual state of the sample. When processing RAP with high mud content or containing light impurities, the fixed overflow height often fails to completely remove surface contaminants without losing fine aggregates, resulting in a low single-rinse pass rate and often requiring re-rinsing. Conversely, when processing samples with high sand content and heavy impurities, the fixed low water level fails to provide sufficient rinsing space, causing impurities to become trapped or settle in dead corners at the bottom of the drum, unable to effectively overflow with the water flow.

[0004] Incomplete cleaning due to structural rigidity directly increases the load and time cost of subsequent drying processes. Given that the trichloroethylene solvent used in subsequent asphalt extraction is prone to hydrolysis and equipment corrosion upon contact with water, RAP must be thoroughly dried at low temperatures (≤60℃). However, the fixed overflow structure prevents phased water control, often resulting in samples carrying excessive amounts of adhering water into the drying stage. Under low-temperature constraints, excess moisture evaporates extremely slowly, significantly extending the drying time for a single batch of samples and forcing the entire experimental cycle to halt due to waiting for drying. Therefore, the existing fixed overflow design not only reduces pretreatment efficiency but is also a significant structural factor contributing to the lengthy RAP regeneration experimental cycle and hindering research and development progress. Utility Model Content

[0005] The purpose of this invention is to solve the problems in the prior art where, during laboratory pretreatment of RAP samples, the fixed overflow structure leads to incomplete cleaning and excessive water content, which, combined with the limitations of low-temperature drying, severely prolongs the experimental cycle.

[0006] To achieve the above objectives, this application proposes a laboratory RAP sample pretreatment purification and drying device, comprising: a washing and desliming zone and a low-temperature drying zone arranged in layers from top to bottom, and a discharge valve connecting the two.

[0007] The washing and mud removal area includes:

[0008] A washing drum; the bottom of the washing drum is provided with a discharge port that communicates with the discharge valve;

[0009] Agitator installed in the washing drum;

[0010] An overflow assembly that can be vertically slidably mounted on the side wall of the washing drum;

[0011] An overflow port is provided on the side wall of the washing drum at a position corresponding to the overflow component.

[0012] In this application, the washing drum serves as the carrying container, and the agitator disturbs the RAP and water, promoting the separation of impurities from the aggregate. The vertically sliding overflow component can adjust its relative height on the side wall according to the sample characteristics, thereby dynamically setting the washing water level. For impurities of different densities, adjusting the overflow layer optimizes the discharge of surface wastewater or the suspension effect of bottom impurities, which helps to reduce the loss of fine aggregate while improving the consistency of the purification effect. After washing, the discharge valve is opened, and the material enters the low-temperature drying zone through the discharge port. Because the water level is controlled in the front end, the water content attached to the sample is optimized, which helps to shorten the drying cycle and improve the overall experimental efficiency under the specified low-temperature environment. This solves the problem in the prior art where the fixed overflow structure leads to incomplete cleaning and excessive water content, which, combined with the limitations of low-temperature drying, seriously prolongs the experimental cycle.

[0013] Furthermore, the overflow assembly includes: an overflow pipe and a drain outlet connected to the side wall of the washing drum, wherein the overflow pipe is vertically and slidably installed on the side wall of the washing drum via a sliding sealing assembly.

[0014] Furthermore, in order to reduce the possibility of the overflow pipe shaking or shifting during the sliding process, and to ensure the sealing of the washing drum, the sliding sealing assembly includes: a mounting base disposed at the end of the overflow pipe; a sliding groove disposed on the side wall of the washing drum and fitted with the mounting base; a sealing strip disposed between the sliding groove and the mounting base; and the mounting base and the side wall of the washing drum are slidably connected by the sliding rail.

[0015] Furthermore, to ensure that impurities can be fully separated from RAP, the agitator includes: an agitator motor mounted on top of the washing drum; and agitator blades extending into the washing drum, the agitator blades being made of a flexible material.

[0016] Furthermore, to facilitate researchers' observation of the separation of RAP samples from impurities and the cleanliness of the water during the washing process, and to facilitate the smooth entry of the sample into the low-temperature drying zone by the discharge valve, the washing cylinder is made of transparent material, and the bottom of the washing cylinder has a conical contraction structure.

[0017] Furthermore, in order to improve the utilization rate of hot air and drying efficiency, and to enable the sample to dry quickly and uniformly, the low-temperature drying zone includes: a drying chamber; a drying tray disposed inside the drying chamber; and an airflow drying system.

[0018] Furthermore, the airflow drying system includes: a blower and an air preheater disposed outside the drying chamber, and an air inlet chamber and an air return chamber disposed inside the drying chamber; the air outlet of the air preheater is connected to the air inlet chamber, and the air inlet chamber and the air return chamber are disposed opposite to each other on both sides of the drying tray.

[0019] Furthermore, in order to ensure that hot air is blown out evenly through narrow gaps, forming a uniform airflow distribution, and that all samples are subjected to uniform hot air blowing to maintain a dry environment inside the drying chamber, a slit-shaped air outlet is provided on the side of the air inlet chamber facing the drying tray, and the air outlet extends along the length of the drying tray; the drying chamber is provided with a dehumidification port, which is connected to the return air chamber.

[0020] Furthermore, in order to allow the moisture on the sample surface to flow along the guide slope to the drain hole, and then collect the moisture discharged from the drain hole through the water collection box, the surface of the drying tray is provided with a guide slope and a drain hole, the drain hole being located at the bottom of the guide slope; a pull-out water collection box is provided below the drying tray, the water collection box being located directly below the drain hole.

[0021] The beneficial effects of this application are as follows:

[0022] 1. In this application, the washing drum serves as the carrying container, and the agitator disturbs the RAP and water, promoting the separation of impurities from the aggregate. The vertically sliding overflow component can adjust its relative height on the side wall according to the sample characteristics, thereby dynamically setting the washing water level. For impurities of different densities, adjusting the overflow layer optimizes the discharge of surface wastewater or the suspension effect of bottom impurities, which helps to reduce the loss of fine aggregate while improving the consistency of the purification effect. After washing, the discharge valve is opened, and the material enters the low-temperature drying zone through the discharge port. Because the water level is controlled in the front end, the water content attached to the sample is optimized, which helps to shorten the drying cycle and improve the overall experimental efficiency under the specified low-temperature environment. This solves the problem in the prior art where the fixed overflow structure leads to incomplete cleaning and excessive water content, which, combined with the limitations of low-temperature drying, seriously prolongs the experimental cycle.

[0023] 2. This application utilizes a guide slope and drainage holes to quickly drain water from the sample surface, reducing the evaporation burden of the airflow. Simultaneously, a uniform, high-speed airflow is created through the slit-shaped air outlet, with the horizontal airflow sweeping across the drying tray surface, improving heat exchange efficiency. The vent promptly removes moisture, maintaining a dry environment. The guide slope drainage reduces the amount of water evaporated. These combined effects shorten the drying time. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of a laboratory RAP sample pretreatment purification and drying device in an embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the sliding sealing assembly in an embodiment of this application;

[0027] Figure 3 This is a diagram showing the positional relationship between the drying tray and the water collection box in an embodiment of this application.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Washing and mud removal zone; 11. Washing drum; 111. Feeding port; 112. Water inlet; 113. Discharge port; 12. Agitator; 121. Agitator motor; 122. Agitator blades; 13. Overflow assembly; 131. Overflow pipe; 132. Drain outlet; 133. Sliding sealing assembly; 1331. Mounting base; 1332. Slide groove; 1333. Sealing strip; 1334. Slide rail; 14. Overflow port;

[0030] 2. Low-temperature drying zone; 21. Drying chamber; 211. Exhaust vent; 22. Drying tray; 221. Guide slope; 222. Drain hole; 23. Airflow drying system; 231. Blower; 232. Air preheater; 233. Air inlet; 234. Air return; 235. Air outlet; 24. Water collection box;

[0031] 3. Discharge valve. Detailed Implementation

[0032] The following will be combined with the appendix Figures 1-3The embodiments of the technical solutions of this application are described in detail below. The following embodiments are only used to more clearly illustrate the technical solutions of this application, and are therefore merely examples and should not be used to limit the scope of protection of this application. Furthermore, the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0033] This application proposes a laboratory RAP sample pretreatment purification and drying device, which aims to solve the problems in the prior art where the fixed overflow structure leads to incomplete cleaning and excessive water content during laboratory RAP sample pretreatment, coupled with the limitation of low temperature drying, which seriously prolongs the experimental cycle.

[0034] For details, please refer to Figures 1-3 The overflow assembly 13 includes an overflow pipe 131 and a drain outlet 132 connected to the side wall of the washing drum 11. The overflow pipe 131 can be vertically and slidably installed on the side wall of the washing drum 11 via a sliding sealing assembly 133.

[0035] The overflow pipe 131 is the core component of the overflow assembly 13, and its main function is to guide the sewage in the washing drum 11 to be discharged. One end of the overflow pipe 131 is connected to the inside of the washing drum 11, and the other end is connected to the drain outlet 132, which can be connected to a drain hose or directly connected to the laboratory's drainage system. During the washing process, when the water level in the washing drum 11 rises to the inlet height of the overflow pipe 131, the upper layer of water containing impurities will automatically flow into the overflow pipe 131 and finally be discharged through the drain outlet 132.

[0036] The sliding sealing assembly 133 is the key structure for achieving height adjustment of the overflow pipe 131. The overflow pipe 131 can be vertically slidably mounted on the side wall of the washing drum 11 via the sliding sealing assembly 133. This means that the overflow pipe 131 can move vertically up and down, adjusting the height of its inlet relative to the bottom of the washing drum 11. This height-adjustable design has the following technical advantages:

[0037] First, the overflow water level can be adjusted according to the processing volume of RAP samples. Different batches of RAP samples require different processing volumes, and therefore different amounts of rinsing water. By adjusting the height of the overflow pipe 131, the water level in the rinsing drum 11 can be changed to accommodate different processing volume requirements. When the processing volume is large, the height of the overflow pipe 131 can be appropriately increased to increase the effective volume within the rinsing drum 11; when the processing volume is small, the height of the overflow pipe 131 can be appropriately decreased to reduce water consumption.

[0038] Secondly, the overflow level can be adjusted based on the density characteristics of the impurities. RAP samples from different sources contain impurities with varying densities and particle sizes. Some impurities are lighter and float on the surface of the water, while others are heavier and tend to settle at the bottom. For RAP samples containing more light impurities, the height of the overflow pipe 131 can be appropriately lowered to facilitate the discharge of upper-layer wastewater. For RAP samples containing more heavy impurities, the height of the overflow pipe 131 can be appropriately increased to increase the water volume, ensuring the impurities are fully suspended before discharge.

[0039] Third, it allows for multi-stage washing with different water levels at different stages. In the initial washing phase, the RAP sample has a high mud content, so a higher water level can be used for thorough washing; in the later washing phase, impurities have been largely removed, so the water level can be lowered to reduce drainage and conserve water resources. The adjustable overflow pipe 131 allows for flexible adjustment of the water level as needed during the same washing process.

[0040] In practical operation, the sliding sealing assembly 133 must ensure both smooth sliding of the overflow pipe 131 and a tight seal of the washing drum 11 to prevent water leakage from the sliding gap. To this end, the sliding sealing assembly 133 can employ various sealing methods, such as rubber sealing rings, O-rings, and sealing strips. The sliding sealing assembly 133 forms a sliding fit with the side wall of the washing drum 11, maintaining a continuous seal during the sliding of the overflow pipe 131.

[0041] The location of drain outlet 132 should facilitate connection to the laboratory drainage system. Drain outlet 132 can be equipped with standard connectors, such as clamp connectors or threaded connectors, to facilitate the connection of drain hoses. A drip tray or bucket can be installed below drain outlet 132 to collect discharged wastewater for subsequent treatment.

[0042] The mounting base 1331 is slidably connected to the side wall of the washing drum 11 via a slide rail 1334.

[0043] Preferably, the sliding sealing assembly 133 can be installed in two ways. One is to install the slide rail 1334 on the outer wall of the washing drum 11, with the mounting base 1331 and slide rail 1334 fitting together on the outer wall of the washing drum 11. In this case, the groove 1332 is opened inward along the outer wall surface of the washing drum 11, forming an externally embedded guide groove structure. The other is to install the slide rail 1334 on the inner wall of the washing drum 11, with the mounting base 1331 and slide rail 1334 fitting together on the inner wall of the washing drum 11. The overflow pipe 131 connected to the mounting base 1331 passes through the washing drum 11 for overflow drainage. In this case, the groove 1332 is opened outward along the inner wall surface of the washing drum 11, forming an internally embedded guide groove structure. Regardless of which of the two methods is chosen, the sealing strip 1333 needs to be placed in the gap between the side wall of the washing drum 11 and the mounting base 1331 to complete the seal.

[0044] This embodiment optimizes the structure of the overflow component 13, especially by setting an adjustable overflow pipe 131, to achieve flexible adjustment of the washing water level, adapt to the washing needs of different processing volumes and different impurities, and improve the applicability and washing effect of the equipment.

[0045] Furthermore, the sliding sealing assembly 133 includes: a mounting base 1331 disposed at the end of the overflow pipe 131; a groove 1332 disposed on the side wall of the washing drum 11 and fitted with the mounting base 1331; and a sealing strip 1333 disposed between the groove 1332 and the mounting base 1331.

[0046] The mounting base 1331 is fixedly installed at the end where the overflow pipe 131 connects to the washing drum 11, and serves as the base component for connecting the overflow pipe 131 to the side wall of the washing drum 11. The mounting base 1331 can have a plate-like structure, the shape of which matches the curvature of the side wall of the washing drum 11, allowing it to fit snugly against the outer or inner wall of the washing drum 11. The mounting base 1331 and the overflow pipe 131 can be fixedly connected by means of integral molding, welding, or threaded connection.

[0047] A chute 1332 is disposed on the side wall of the washing drum 11 and serves as a guide structure for the sliding of the mounting base 1331. The chute 1332 extends vertically, forming a long, narrow groove-shaped structure whose cross-sectional shape matches that of the mounting base 1331, allowing the mounting base 1331 to be embedded within it and slide vertically. The length of the chute 1332 determines the adjustable height range of the overflow pipe 131; the longer the chute 1332, the greater the height adjustment range of the overflow pipe 131.

[0048] A sealing strip 1333 is disposed between the slide groove 1332 and the mounting base 1331. When the mounting base 1331 is embedded in the slide groove 1332 and slides along it, the sealing strip 1333 always fills the gap between the two, preventing water in the washing drum 11 from leaking out of the gap. Optionally, the sealing strip 1333 can be made of elastic materials such as rubber, silicone, or polyurethane, which have good elasticity and water resistance. It should be noted that the sealing strip 1333 needs to be bonded to the slide groove 1332 to ensure that the relative position of the slide groove 1332 and the sealing strip 1333 is fixed, while the relative displacement of the mounting base 1331 and the slide groove 1332 allows for the adjustment of the entire overflow height.

[0049] The working principle of the sliding sealing assembly 133 in this embodiment is as follows:

[0050] When the height of the overflow pipe 131 needs to be adjusted, the operator can manually push the overflow pipe 131 up or down. The movement of the overflow pipe 131 causes the mounting base 1331 to slide within the groove 1332. Since the sealing strip 1333 is set between the groove 1332 and the mounting base 1331, when the mounting base 1331 slides, the sealing strip 1333 is compressed and deformed, always tightly fitting against the inner wall of the groove 1332 and the surface of the mounting base 1331, maintaining a sealed state. When the overflow pipe 131 is adjusted to the required height, pushing stops, and the overflow pipe 131 remains in its current position under the action of friction or the locking mechanism. Water in the washing drum 11 will not leak from the sliding gap due to the sealing effect of the sealing strip 1333.

[0051] The above-described structural design of the sliding sealing assembly 133 has the following technical advantages:

[0052] First, it reduces the possibility of the overflow pipe 131 wobbling or shifting during sliding. The mounting base 1331 is fitted into the sliding groove 1332, which guides and limits the mounting base 1331, ensuring that the overflow pipe 131 can only slide vertically and does not wobble or shift horizontally. This stable sliding method helps maintain the sealing effect of the sealing strip 1333 and extends its service life.

[0053] Secondly, ensure the sealing performance of the washing drum 11. A sealing strip 1333 is positioned between the sliding groove 1332 and the mounting base 1331, effectively filling the gap between them and preventing water leakage. The elasticity of the sealing strip 1333 allows it to automatically adapt to changes in the gap during sliding, maintaining a continuous sealing effect.

[0054] Third, it has a simple structure and is easy to operate. The sliding sealing assembly 133 consists of three main components: a mounting base 1331, a sliding groove 1332, and a sealing strip 1333. It has a simple structure and is easy to manufacture. Operators only need to push the overflow pipe 131 to complete the height adjustment, making the operation simple and quick.

[0055] In practical applications, scale lines can be set on one or both sides of the slide groove 1332 to facilitate operators in visually judging the height position of the overflow pipe 131. Locking screws or locking clips can also be set on the mounting base 1331. After the overflow pipe 131 is adjusted to the required height, the mounting base 1331 can be fixed to the slide groove 1332 by locking screws or locking clips to prevent the overflow pipe 131 from accidentally sliding during use.

[0056] The cross-sectional shape of the sealing strip 1333 can be O-shaped, U-shaped, V-shaped, or flat strip, etc., and the selection is based on the structure of the groove 1332 and the mounting base 1331. The sealing strip 1333 can be fixed to the inner wall of the groove 1332, or fixed to the surface of the mounting base 1331, or the sealing strip 1333 can be provided on both sides to enhance the sealing effect.

[0057] This embodiment refines the structure of the sliding sealing assembly 133, achieving an organic combination of stability and sealing performance in the height adjustment of the overflow pipe 131, thereby improving the operational reliability and service life of the overflow assembly 13.

[0058] Furthermore, the device adopts a layered structure from top to bottom, organically integrating the washing and desliming zone with the low-temperature drying zone. A discharge valve connects the two functional zones, forming a complete sample pretreatment system. (See also...) Figures 1 to 3 As shown, this embodiment provides a laboratory RAP sample pretreatment purification and drying device. The device adopts a vertical layered structure design and mainly includes: a washing and mud removal zone 1 and a low temperature drying zone 2 arranged from top to bottom, and a discharge valve 3 connecting the two.

[0059] From the perspective of functional division of labor, the washing and desliming zone 1 is located at the top of the device and is mainly responsible for washing and removing impurities from the RAP samples. The material is added from the feed port 111 and the water is added from the inlet port 112. The low-temperature drying zone 2 is located at the bottom of the device and is mainly responsible for the low-temperature drying of the RAP samples after washing. The discharge valve 3 is set between the washing and desliming zone 1 and the low-temperature drying zone 2, which serves to connect or block the two functional zones, and at the same time controls the flow rate and speed of the RAP samples transferred from the washing and desliming zone 1 to the low-temperature drying zone 2.

[0060] Specifically, the washing and desliming zone 1 includes: a washing drum 11, which provides the main space for washing RAP samples; a stirrer 12 installed in the washing drum 11, used to stir and mix the RAP samples and water in the washing drum 11 to accelerate the separation of impurities from the RAP samples; and an overflow assembly 13 installed on the side wall of the washing drum 11, used to discharge wastewater generated during the washing process and maintain a stable water level in the washing drum 11. The side wall of the washing drum 11 has an overflow port 14 for installing the overflow assembly 13. The overflow port 14 is an opening on the side wall of the washing drum 11, and the overflow assembly 13 is installed at this opening via a sliding sealing assembly 133. The bottom of the washing drum 11 has a discharge port 113, which is connected to a discharge valve 3 for conveying the washed RAP samples to the low-temperature drying zone 2 through the discharge valve 3.

[0061] The low-temperature drying zone 2 includes: a drying chamber 21, which provides an enclosed space for drying RAP samples; a drying tray 22 disposed inside the drying chamber 21, used to receive and place RAP samples transported from the washing and desliming zone 1, wherein the drying tray 22 is installed on the inner walls of opposite sides inside the drying chamber 21 by means of a U-shaped connecting plate, and the installation is completed by means of bolts fasteners passing through threaded holes opened in the U-shaped connecting plate, so that the ends of the bolts fasteners press against the inner wall of the drying chamber 21; and an airflow drying system 23, used to provide preheated airflow into the drying chamber 21 to accelerate the evaporation of moisture on the surface of the RAP samples and achieve rapid drying under low-temperature conditions.

[0062] Specifically, during RAP sample pretreatment, the RAP sample to be treated is first placed into the washing drum 11 of the washing and desludge removal zone 1, and clean water is injected into the washing drum 11. The stirrer 12 is then started, mixing the RAP sample and water in the washing drum 11 to ensure that impurities such as mud and dust mixed in the RAP sample are fully mixed with the water to form a suspension. Due to the low density of the impurities, they will remain suspended in the water during the stirring process. As water is continuously injected and stirring continues, wastewater is discharged through the overflow component 13 located on the side wall of the washing drum 11, achieving continuous removal of impurities. Once the discharged water becomes clear, water injection is stopped, and stirring continues for several minutes to ensure complete separation of impurities.

[0063] After washing, the discharge valve 3 is opened, and the RAP sample in the washing cylinder 11 falls into the drying tray 22 of the low-temperature drying zone 2 under the action of gravity through the discharge port 113 and the discharge valve 3. After closing the discharge valve 3, the airflow drying system 23 is started. The airflow drying system 23 provides preheated airflow into the drying chamber 21. The hot air flows over the surface of the RAP sample on the drying tray 22, carrying away the moisture on the sample surface. Because the air is preheated, the temperature is controlled below 60℃, avoiding the problem of secondary aging of the old asphalt in the RAP sample. After a certain period of drying, the RAP sample reaches the specified degree of dryness and can be taken out for subsequent asphalt recycling and performance testing experiments.

[0064] This embodiment integrates the washing and desliming zone 1 and the low-temperature drying zone 2 into one unit, achieving a one-stop processing of RAP samples from washing to drying. This avoids the cumbersome operation of transferring samples from one device to another in traditional methods, greatly improving work efficiency. Simultaneously, the design of the airflow drying system 23 enables rapid drying even at low temperatures, solving the problem of low-temperature drying efficiency.

[0065] Further, see Figure 1As shown, the stirrer 12 includes a stirring motor 121 mounted on top of the washing drum 11, and stirring blades 122 extending into the washing drum 11. The stirring motor 121 is fixedly mounted at the center of the top of the washing drum 11, and its output shaft extends downward into the washing drum 11. The stirring blades 122 are mounted on the end of the output shaft of the stirring motor 121 and rotate under the drive of the stirring motor 121 to stir and mix the RAP sample and water in the washing drum 11.

[0066] It is particularly important to note that the stirring blade 122 is made of a flexible material. This flexible material can be rubber, silicone, polyurethane elastomer, nylon, or other materials with a certain degree of flexibility and elasticity. Using a flexible material to manufacture the stirring blade 122 has the following technical advantages:

[0067] First, RAP samples typically consist of aggregates and asphalt of varying particle sizes, including larger stones. If traditional rigid metal mixing blades are used, collisions between the blades and stones during high-speed rotation can easily cause breakage and damage to the RAP sample, altering its original gradation and affecting the accuracy of subsequent experiments. However, the flexible mixing blades 122 undergo elastic deformation upon impact with stones, avoiding hard collisions and protecting the integrity of the RAP sample.

[0068] Secondly, the flexible stirring blades 122 can generate better water flow disturbance during rotation and stirring, forming a more uniform water flow field, which is conducive to the full separation of impurities such as soil from the RAP sample. The flexible blades will undergo a certain degree of bending deformation when rotating, which changes the contact area and contact angle between the blades and water, generating more complex and diverse water flow disturbance patterns, resulting in better mixing effect compared to rigid blades.

[0069] Furthermore, the flexible stirring blades 122 exhibit more uniform wear and a longer service life. During long-term stirring operations, the blades inevitably experience frictional wear against hard particles in the RAP sample. The elasticity of the flexible material allows the blade surface to better adapt to wear, reducing the likelihood of excessive localized wear, thus extending the blade's service life and lowering equipment maintenance costs.

[0070] In practical applications, the stirring blades 122 can adopt an integral flexible structure or a composite structure in which a flexible layer is wrapped around a rigid frame. The number of stirring blades 122 can be reasonably set according to the volume of the washing cylinder 11 and the processing volume of RAP samples, generally set to 2-4 blades, evenly distributed around the stirring shaft. The shape of the stirring blades 122 can take various forms such as flat plate, arc plate, and spiral to adapt to different stirring requirements.

[0071] The speed of the stirring motor 121 can be adjusted to meet the washing requirements of RAP samples with different properties. For RAP samples with high mud content and difficult-to-separate impurities, a higher speed can be used to enhance the stirring intensity; for RAP samples that have undergone preliminary treatment and have fewer impurities, a lower speed can be used to reduce energy consumption and equipment wear.

[0072] This embodiment optimizes the structure of the stirrer 12, especially by using flexible material to make the stirring blades 122. This ensures the washing effect while effectively protecting the integrity of the RAP sample, avoiding sample breakage and gradation changes caused by stirring, and improving the quality of sample pretreatment.

[0073] Further, see Figure 1 and Figure 2 As shown, the body of the washing tube 11 is made of transparent material, and the bottom of the washing tube 11 has a tapered conical structure.

[0074] The body of the washing drum 11 is made of a transparent material, such as tempered glass, plexiglass, or polycarbonate, which possesses good transparency and mechanical strength. Using a transparent material to make the body of the washing drum 11 offers several technical advantages:

[0075] First, it allows researchers to observe the separation of RAP samples from impurities in real time during the washing process. In practice, the washing effect of RAP samples directly affects the accuracy of subsequent experiments. Insufficient washing will result in residual impurities interfering with the experimental results; excessive washing will waste time and water resources. Through the transparent cylinder, researchers can directly observe the state of the RAP sample in the water, the suspension and sedimentation of impurities, and changes in water color, thus accurately determining whether the washing has achieved the expected results.

[0076] Secondly, it facilitates observation of water level changes and the cleanliness of the wastewater within the washing drum 11. During the washing process, continuous water injection and drainage are required, and the water level directly affects the effectiveness of the overflow component 13. Through the transparent drum, researchers can clearly see the water level changes and adjust the injection volume in a timely manner to maintain a suitable water level. Simultaneously, the degree of impurity removal can be judged by observing the color and transparency of the discharged water. When the discharged water becomes clear and transparent, it indicates that the impurities have been largely removed, and washing can be stopped.

[0077] Third, it facilitates observation of the RAP sample flow at discharge valve 3, ensuring smooth entry of the sample into the low-temperature drying zone 2. When discharge valve 3 is opened, the transparent cylinder allows observation of whether the RAP sample flows out smoothly or whether there is any blockage, enabling timely intervention to ensure smooth operation.

[0078] The bottom of the washing drum 11 has a conical contraction structure, meaning that the drum body of the washing drum 11 gradually contracts from top to bottom, forming a conical bottom structure. This conical contraction structure has the following technical advantages:

[0079] First, it facilitates the smooth collection of the washed RAP sample at the discharge port 113. After washing, the RAP sample needs to enter the low-temperature drying zone 2 through the discharge valve 3. The conical shrinkage structure allows the RAP sample to slide naturally to the discharge port 113 in the center of the bottom of the cylinder under the action of gravity, avoiding the accumulation of sample at the corners of the bottom of the cylinder, ensuring that the sample can be completely discharged and reducing sample residue.

[0080] Secondly, the conical contraction structure facilitates connection and sealing with the discharge valve 3. The contraction end at the bottom of the cone can directly connect to the inlet of the discharge valve 3, forming a smooth transition, reducing dead angles at the connection, and facilitating the flow of RAP samples. At the same time, the seal between the conical structure and the discharge valve 3 is more reliable, preventing leakage during the washing process.

[0081] In practical applications, the transparent portion of the washing cylinder 11 can be made fully transparent or partially transparent. Full transparency means the entire cylinder is made of transparent material, facilitating all-around observation; partial transparency means that strip-shaped or window-shaped transparent areas are set on the cylinder, meeting basic observation needs while reducing manufacturing costs. Graduation lines can be set in the transparent areas to help researchers determine the amount of water injected and the sample volume.

[0082] This embodiment optimizes the structure of the washing cylinder 11, especially by using transparent material to make the cylinder body and setting a conical constriction bottom, making the experimental operation more convenient and intuitive, the sample discharge smoother and more thorough, and improving the operability and practicality of the equipment.

[0083] Furthermore, the airflow drying system 23 includes: a blower 231 and an air preheater 232 disposed outside the drying chamber 21, and an air inlet chamber 233 and an air return chamber 234 disposed inside the drying chamber 21. The air outlet of the air preheater 232 is connected to the air inlet chamber 233, and the air inlet chamber 233 and the air return chamber 234 are disposed opposite each other on both sides of the drying tray 22 to form a horizontal airflow that sweeps across the surface of the drying tray 22.

[0084] Blower 231 is the power source for the airflow drying system 23, and its function is to provide the airflow required for drying. The air inlet of blower 231 is connected to the atmosphere, and the air outlet is connected to the air inlet of air preheater 232. Blower 231 can be a centrifugal fan, axial fan, etc., and the appropriate specification and model should be selected according to the volume of drying chamber 21 and the drying speed requirements.

[0085] The function of the air preheater 232 is to heat the ambient temperature air supplied by the blower 231 to a suitable drying temperature. Since the drying temperature of RAP samples cannot exceed 60℃, the air preheater 232 should be equipped with a precise temperature control device to ensure that the temperature of the output air remains stable within the set range. The air preheater 232 can be in the form of an electric heater, a hot water heat exchanger, or a steam heat exchanger. Electric heaters have the advantages of simple structure and convenient control, making them suitable for laboratory environments. Multiple heating elements can be installed inside the air preheater 232, allowing for multi-level temperature adjustment through group control. Simultaneously, the air preheater 232 should be equipped with a temperature sensor to monitor the temperature of the output air in real time and feed the temperature signal back to the controller to achieve closed-loop temperature control.

[0086] An air inlet chamber 233 is located inside the drying chamber 21 on one side. Its function is to evenly distribute preheated air into the drying area. The air inlet chamber 233 is connected to the air outlet of the air preheater 232 to receive the preheated air. An air outlet is provided on the side of the air inlet chamber 233 facing the drying tray 22. Hot air flows out through the air outlet and blows onto the RAP sample on the drying tray 22.

[0087] The return air chamber 234 is located on the other side of the interior of the drying chamber 21, opposite to the inlet air chamber 233. The function of the return air chamber 234 is to collect the humid and hot air that has flowed over the surface of the drying tray 22 and discharge it or bring it back for recycling. The inlet air chamber 233 and the return air chamber 234 are located opposite each other on the two sides of the drying tray 22, so that the hot air flowing out of the inlet air chamber 233 can form a horizontal airflow that sweeps over the surface of the drying tray 22 and then enters the return air chamber 234.

[0088] This structure of the relatively arranged air inlet chamber 233 and return chamber 234 forms a horizontal airflow path that sweeps across the surface of the drying tray 22, and has the following technical advantages:

[0089] First, it improves the utilization rate of hot air. The horizontal airflow flows from one side of the drying tray 22 to the other, ensuring full contact with the RAP sample on the drying tray 22, transferring heat and removing moisture. Compared to the vertically downward blowing airflow, the horizontal airflow has a longer residence time on the surface of the drying tray 22, resulting in more complete heat exchange and higher thermal efficiency.

[0090] Secondly, it enables the samples to dry quickly and uniformly. The horizontal airflow along the length of the drying tray 22 ensures even coverage of all samples on the tray, preventing localized over- or under-drying. Uniform drying helps maintain the consistency of RAP sample performance and improves the accuracy of subsequent experimental results.

[0091] Third, it facilitates the integration with other components to form an airflow circulation. The separate placement of the air inlet chamber 233 and the return air chamber 234 on opposite sides allows for easy connection via pipes to form an airflow circulation loop. The humid and hot air collected in the return air chamber 234 can be dehumidified and then reintroduced into the air preheater 232, achieving heat recovery and utilization, and improving energy efficiency.

[0092] In practical applications, the air inlet cavity 233 and the air return cavity 234 can adopt various structural forms. The air inlet cavity 233 can be designed as a long strip-shaped cavity extending along the length of the drying tray 22, with continuous air outlets or multiple air outlets on the side facing the drying tray 22. Similarly, the air return cavity 234 can be designed as a long strip-shaped cavity extending along the length of the drying tray 22, with continuous return air inlets or multiple return air outlets on the side facing the drying tray 22. The cross-sectional shape of the air inlet cavity 233 and the air return cavity 234 can be rectangular, circular, or other shapes, and should be rationally designed according to the internal space of the drying chamber 21.

[0093] The air outlet of the air preheater 232 and the air inlet chamber 233 can be connected by an air duct. The air duct should have good insulation performance to reduce heat loss. The connection between the air duct and the drying chamber 21 should be well sealed to prevent hot air leakage. Similarly, the return air chamber 234 should also be sealed to the subsequent exhaust pipe or circulation pipe.

[0094] This embodiment optimizes the structure of the airflow drying system 23, especially by setting up the relatively arranged air inlet chamber 233 and return chamber 234, forming an efficient airflow path, improving drying efficiency and drying uniformity, and meeting the requirements of low-temperature rapid drying of RAP samples.

[0095] Furthermore, this embodiment further refines the design of the air inlet chamber 233 and the drying chamber 21. Specifically, the air inlet chamber 233 has a slit-shaped air outlet 235 on the side facing the drying tray 22, and the air outlet 235 extends along the length of the drying tray 22; the drying chamber 21 has a dehumidification port 211, which communicates with the return air chamber 234.

[0096] The slit-shaped air outlet 235 is a key component of the air inlet chamber 233, and its structure directly affects the distribution characteristics of the drying airflow. The air outlet 235 is designed as a slit, meaning its width is much smaller than its length, forming a narrow, elongated air outlet gap. The air outlet 235 extends along the length of the drying tray 22, meaning its length direction is consistent with the length direction of the drying tray 22. This slit-shaped air outlet 235 design has the following technical advantages:

[0097] First, it allows hot air to be blown out evenly through a narrow gap, forming a uniform airflow distribution. The slit-shaped air outlet 235 confines the hot air flowing out of the air inlet 233 to a narrow width range, resulting in a relatively high airflow velocity and a well-directional airflow. Simultaneously, the slit extends along the length of the drying tray 22, ensuring that the airflow is evenly distributed along its length, guaranteeing that samples at all points on the drying tray 22 are subjected to approximately the same intensity of hot air.

[0098] Secondly, it ensures that all samples are uniformly exposed to hot air. Since the air outlet 235 is a narrow slit extending continuously along the length of the drying tray 22, the hot air flowing out of the slit forms an air curtain along the width of the drying tray 22. This air curtain blows from one side of the drying tray 22 to the other, covering the entire width of the drying tray 22. When RAP samples are placed on the drying tray 22, each sample particle is uniformly exposed to hot air, avoiding uneven airflow where some areas have high airflow and others have low airflow.

[0099] Third, it enhances the airflow velocity and penetration. The slit-shaped air outlet 235 allows the same flow rate of air to exit through a smaller cross-sectional area, resulting in a relatively higher airflow velocity. This higher airflow velocity allows hot air to better penetrate the surface of the RAP sample layer and reach deep into the sample interior, accelerating the evaporation of moisture between sample particles. Simultaneously, the high-speed airflow has a "sweeping" effect on the sample surface, carrying away water droplets adhering to the sample surface and accelerating the drying process.

[0100] The width of the air outlet 235 should be designed reasonably based on factors such as the width of the drying tray 22, the air volume of the blower 231, and the desired air velocity. Generally, the width of the air outlet 235 can be selected within the range of 3-10mm. The length of the air outlet 235 should be close to or equal to the length of the drying tray 22 to ensure that the airflow can cover the entire drying area.

[0101] A humidifier 211 is installed on the drying chamber 21, and its function is to exhaust the humid and hot air generated during the drying process from the drying chamber 21. The humidifier 211 is connected to the return air chamber 234, and the humid and hot air collected in the return air chamber 234 is discharged through the humidifier 211. The humidifier 211 can be located on the top, side wall, or rear wall of the drying chamber 21, depending on the overall layout of the equipment.

[0102] The exhaust port 211 can be connected to an exhaust pipe to guide humid and hot air outdoors or into a dehumidification device. A regulating valve can be installed on the exhaust pipe to control the exhaust speed. The cross-sectional dimensions of the exhaust port 211 should be reasonably designed according to the exhaust volume requirements to ensure that humid and hot air can be smoothly discharged and will not accumulate inside the drying chamber 21.

[0103] In this embodiment, the drying chamber 21 maintains a certain negative pressure or slightly positive pressure, which is conducive to the removal of moisture. A small exhaust fan can be installed at the exhaust port 211 to enhance the dehumidification effect. The connection between the exhaust port 211 and the return air chamber 234 should be well sealed to prevent hot and humid air from leaking into other parts of the drying chamber 21 and affecting the drying effect.

[0104] Maintaining a good drying environment inside the drying chamber 21 is crucial to ensuring the drying quality of RAP samples. By properly designing the slit-shaped air outlet 235 and the dehumidification outlet 211, hot air can be evenly blown onto the sample, and humid hot air can be promptly discharged, forming a stable airflow circulation. This keeps the relative humidity inside the drying chamber 21 at a low level, which is conducive to the rapid evaporation of moisture from the sample.

[0105] This embodiment refines the structure of the air inlet 233, air outlet 235, and moisture exhaust port 211 of the drying chamber 21, thereby achieving uniform distribution of the drying airflow and effective removal of moisture, thus improving drying efficiency and drying uniformity.

[0106] Furthermore, the surface of the drying tray 22 is provided with a guide slope 221 and a drain hole 222, with the drain hole 222 located at the bottom of the guide slope 221; a pull-out water collection box 24 is provided below the drying tray 22, with the water collection box 24 located directly below the drain hole 222.

[0107] The guide slope 221 is a groove structure set on the surface of the drying tray 22. Its main function is to guide the water on the surface of the RAP sample to the drain hole 222. The guide slope 221 can be arranged in various forms, such as straight, grid, and radial. The straight guide slope 221 is set along the inclined direction of the drying tray 22, and the water flows in a straight line; the grid guide slope 221 forms a grid-like groove on the surface of the drying tray 22, and the water flows along each groove; the radial guide slope 221 radiates from the center of the drying tray 22 to the periphery, and the water flows from the center to the edge.

[0108] The cross-sectional shape of the guide slope 221 can be V-shaped, U-shaped, or rectangular. V-shaped guide slopes are easy to process and have good drainage; U-shaped guide slopes are easy to clean; and rectangular guide slopes have a simple structure. The depth and width of the guide slope 221 should be rationally designed according to the particle size and drainage volume of the RAP sample. Generally, the depth can be selected within the range of 2-5 mm, and the width within the range of 3-8 mm.

[0109] Drainage hole 222 is a through hole penetrating the drying tray 22, located at the bottom of the guide slope 221, used to drain the moisture collected on the guide slope 221 to the bottom of the drying tray 22. One or more drainage holes 222 can be provided, determined according to the area of ​​the drying tray 22 and drainage requirements. The diameter of the drainage hole 222 should be moderate; too small a diameter can easily cause clogging, while too large a diameter may cause RAP sample particles to fall out of the hole. Generally, the diameter can be selected in the range of 3-6 mm.

[0110] When the RAP sample falls from the washing and desliming zone 1 into the drying tray 22, a large amount of moisture adheres to the sample surface. This moisture flows along the guide slope 221 under gravity, collects at the drain hole 222, and drips down into the drying tray 22. The design of the guide slope 221 and the drain hole 222 allows the moisture on the RAP sample surface to drain quickly, reducing drying time.

[0111] A water collection box 24 is located below the drying tray 22 to collect water discharged from the drain hole 222. The water collection box 24 can be designed as a drawer-type structure, which can be pulled out from the front or side of the drying chamber 21. The water collection box 24 is located directly below the drain hole 222 to ensure that water dripping from the drain hole 222 falls accurately into the water collection box 24.

[0112] The capacity of the water collection box 24 should be rationally designed based on the processing volume and water content of the RAP sample. Generally, the water content of 1 kg of RAP sample after washing is about 100-200 ml, and the capacity of the water collection box 24 should be able to hold the water discharged from at least one batch of RAP sample. The material of the water collection box 24 should be selected from corrosion-resistant and easy-to-clean materials, such as stainless steel or plastic.

[0113] The water collection box 24 can be equipped with a liquid level observation window or a liquid level gauge, allowing operators to easily observe the water level inside the water collection box 24 and clean it in a timely manner. The water collection box 24 can be equipped with a handle for easy pulling operation. A sealing structure can be installed between the water collection box 24 and the drying chamber 21 to prevent moisture from evaporating into the drying chamber 21 and affecting the drying effect.

[0114] The combined design of the guide slope 221, the drainage hole 222, and the water collection box 24 has the following technical advantages:

[0115] First, it allows moisture on the sample surface to flow along the guide slope 221 to the drain hole 222 and be quickly discharged from the drying tray 22. After the RAP sample is transferred from the washing and desliming area 1 to the drying tray 22, the moisture adhering to the surface is quickly collected along the guide slope 221 and discharged from the drain hole 222 under the action of gravity, reducing the amount of water that needs to be evaporated by airflow and shortening the drying time.

[0116] Secondly, the water discharged from the drain hole 222 is collected by the water collection box 24 for centralized treatment. The discharged water is collected in the water collection box 24 and will not flow around inside the drying chamber 21, keeping the inside of the drying chamber 21 clean. The water collection box 24 can be removed and cleaned periodically, making it easy to operate.

[0117] Third, it reduces the humidity inside the drying chamber 21 and improves drying efficiency. Most of the moisture is quickly discharged through the guide slope 221 and the drain hole 222, reducing the amount of water evaporated into the air inside the drying chamber 21 and lowering the relative humidity inside the drying chamber 21. This allows the airflow drying system 23 to more effectively remove the remaining moisture from the sample.

[0118] In practical applications, the drying tray 22 can be designed as a detachable structure for easy regular cleaning and maintenance. The drying tray 22 can be designed as a plate-shaped structure with a border; the border height should be appropriate to prevent RAP samples from falling off the tray edge without obstructing airflow. The drying tray 22 should be made of corrosion-resistant and thermally conductive materials, such as stainless steel or aluminum alloy.

[0119] This embodiment optimizes the drying tray 22 and the water collection structure, enabling rapid drainage and collection of moisture from the RAP sample surface, improving drying efficiency and simplifying cleaning.

[0120] Furthermore, a load cell is installed below the drying tray 22. The load cell is positioned on the side of the support structure of the drying tray 22 or next to the water collection box 24 to avoid conflict with the drainage path and the movement space of the water collection box 24. The signal output terminal of the load cell is connected to the controller, which is connected to and controls the blower 231 and the air preheater 232.

[0121] The primary function of the load cell is to monitor the weight changes of the RAP samples on the drying tray 22 in real time. Various types of load cells can be used, including resistance strain gauge, piezoelectric, and capacitive types, selected based on measurement accuracy and range requirements. The load cell's range should cover the processing volume of RAP samples, and its accuracy should meet the requirements for weight change monitoring.

[0122] One or more load cells can be installed. When a single load cell is installed, it can be positioned below the center of the drying tray 22 or below any support point of the drying tray 22's support structure. When multiple load cells are installed, they can be evenly distributed below the support points of the drying tray 22, and the total weight is obtained by superimposing the signals from each sensor.

[0123] The working principle of determining the degree of dryness by real-time monitoring of RAP sample weight changes using a weighing sensor is as follows:

[0124] When the RAP sample is transferred to drying tray 22 after washing, it contains a large amount of moisture; its weight at this point is called wet weight. During the drying process, the sample weight gradually decreases as the moisture evaporates. When the sample is dried to a certain extent, its weight tends to stabilize and no longer decreases significantly; this weight is called dry weight. By monitoring the weight change, the degree of dryness of the sample can be determined.

[0125] The controller can be a microcontroller, PLC, industrial control computer or other control equipment. Its main function is to receive the weight signal from the weighing sensor, process and analyze it, and control the working status of the blower 231 and the air preheater 232 according to the analysis results.

[0126] The controller can employ the following control strategies:

[0127] First, when the weight on the drying tray 22 reaches a stable state, that is, the weight change per unit time is less than the set threshold, it is determined that the sample has been dried, the blower 231 and the air preheater 232 are automatically stopped, and a prompt signal is issued to notify the operator to pick up the material.

[0128] Second, the rotational speed of blower 231 is controlled according to the rate of weight change. In the initial stage of drying, the sample has a high moisture content and the weight changes rapidly, so a higher wind speed can be used to accelerate drying; in the later stage of drying, the sample has a low moisture content and the weight changes slowly, so the wind speed can be reduced to save energy.

[0129] Third, the heating power of the air preheater 232 is controlled according to the weight change. In the early stage of drying, a larger heating power is required to maintain a higher air temperature; in the later stage of drying, the heating power can be reduced to avoid overheating of the sample.

[0130] The controller can also be equipped with a display screen to show information such as weight, weight change rate, drying time, and drying temperature on the drying tray 22 in real time, making it easy for operators to monitor the drying process.

[0131] The installation of load cells has the following technical advantages:

[0132] First, it enables automatic judgment of the degree of dryness, avoiding over-drying or under-drying. Traditional methods rely primarily on operator experience or timed controls to determine whether a sample is dry enough, which is subjective and uncertain. By using a weighing sensor to monitor weight changes in real time, the degree of dryness can be accurately determined, ensuring drying quality.

[0133] Second, the drying process is optimized to save energy. The controller automatically adjusts the working status of the blower 231 and the air preheater 232 according to the weight change, avoiding the equipment from continuing to run after the sample has dried, thus saving energy consumption.

[0134] Third, it enables the automation and intelligentization of the drying process. With the help of a controller, the drying process can be automatically monitored and controlled, reducing manual intervention, improving work efficiency, and lowering labor intensity.

[0135] In practical applications, load cells should be protected against moisture, dust, vibration, and other harmful factors. A protective cover can be installed on the outside of the load cell to prevent water dripping from the drain hole 222 from splashing onto the sensor. The load cell should be calibrated regularly to ensure measurement accuracy. The controller should have a parameter setting interface, allowing operators to set different drying termination conditions for different types of RAP samples, such as weight stabilization time and weight change threshold.

[0136] The workflow is as follows:

[0137] Step 1: RAP Sample Washing. Place the RAP sample to be processed into the washing cylinder 11, add water, and start the stirrer 12. Adjust the height of the overflow pipe 131 according to the sample volume to control the water level. Observe the washing process through the transparent cylinder; stop washing when the discharged water is clear.

[0138] Step 2: Sample Transfer. Open the discharge valve 3. Under the influence of gravity, the RAP sample collects at the discharge port 113 through the conical bottom and falls onto the drying tray 22. Moisture on the sample surface flows along the guide slope 221 to the drain hole 222 and drips into the water collection box 24.

[0139] Step 3: Low-temperature drying. The airflow drying system 23 is activated. The blower 231 sends air into the air preheater 232 for heating. The hot air enters the air inlet chamber 233 and flows out from the slit-shaped air outlet 235, forming a horizontal airflow that sweeps across the surface of the drying tray 22, carrying away moisture from the sample. The hot, humid air enters the return air chamber 234 and is discharged from the exhaust port 211. A weighing sensor monitors the weight change in real time, and the controller controls the drying process based on the weight changes.

[0140] Step 4: Drying Completed. When the weight stabilizes, the controller determines that drying is complete, automatically stops the equipment, and issues a notification signal. The operator then removes the dried RAP sample for subsequent experiments.

[0141] In the description of the embodiments of this application, the technical terms "upper", "lower", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0142] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "set," "equipped with," "connected," and "installed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0143] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A laboratory RAP sample pretreatment, purification, and drying device, characterized in that, include: The washing and sludge removal zone (1) and the low-temperature drying zone (2) are arranged in layers from top to bottom, and the discharge valve (3) connects the two. The washing and mud removal zone (1) includes: Washing drum (11); The bottom of the washing drum (11) is provided with a discharge port (113) that communicates with the discharge valve (3); Agitator (12) is installed in the washing drum (11); An overflow assembly (13) can be vertically slidably mounted on the side wall of the washing drum (11). An overflow port (14) is provided on the side wall of the washing drum (11) at a position corresponding to the overflow assembly (13).

2. The laboratory RAP sample pretreatment purification and drying apparatus according to claim 1, characterized in that, The overflow assembly (13) includes an overflow pipe (131) and a drain outlet (132) connected to the side wall of the washing drum (11). The overflow pipe (131) is vertically and slidably installed on the side wall of the washing drum (11) via a sliding sealing assembly (133).

3. The laboratory RAP sample pretreatment purification and drying apparatus according to claim 2, characterized in that, The sliding sealing assembly (133) includes: a mounting base (1331) disposed at the end of the overflow pipe (131); a groove (1332) disposed on the side wall of the washing drum (11) and fitted with the mounting base (1331); a sealing strip (1333) disposed between the groove (1332) and the mounting base (1331); the mounting base (1331) and the side wall of the washing drum (11) are slidably connected by a slide rail (1334).

4. The laboratory RAP sample pretreatment purification and drying apparatus according to claim 1, characterized in that, The agitator (12) includes: an agitator motor (121) mounted on the top of the washing drum (11); and agitator blades (122) extending into the washing drum (11), the agitator blades (122) being made of a flexible material.

5. The laboratory RAP sample pretreatment purification and drying apparatus according to claim 1, characterized in that, The body of the washing tube (11) is made of transparent material, and the bottom of the washing tube (11) has a tapered conical structure.

6. The laboratory RAP sample pretreatment purification and drying apparatus according to claim 1, characterized in that, The low-temperature drying zone (2) includes: a drying chamber (21); a drying tray (22) disposed inside the drying chamber (21); and an airflow drying system (23).

7. The laboratory RAP sample pretreatment purification and drying apparatus according to claim 6, characterized in that, The airflow drying system (23) includes: a blower (231) and an air preheater (232) disposed outside the drying chamber (21), and an air inlet chamber (233) and an air return chamber (234) disposed inside the drying chamber (21); the air outlet of the air preheater (232) is connected to the air inlet chamber (233), and the air inlet chamber (233) and the air return chamber (234) are disposed opposite to each other on both sides of the drying tray (22).

8. The laboratory RAP sample pretreatment purification and drying apparatus according to claim 7, characterized in that, The air inlet cavity (233) has a slit-shaped air outlet (235) on the side facing the drying tray (22), and the air outlet (235) extends along the length of the drying tray (22); the drying box (21) has a dehumidification port (211), and the dehumidification port (211) is connected to the return air cavity (234).

9. The laboratory RAP sample pretreatment purification and drying apparatus according to claim 6, characterized in that, The surface of the drying tray (22) is provided with a guide slope (221) and a drain hole (222), the drain hole (222) being located at the bottom of the guide slope (221); a pull-out water collection box (24) is provided below the drying tray (22), the water collection box (24) being located directly below the drain hole (222).

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