A low temperature drying system and method suitable for natural rubber

Abstract

The present application relates to a kind of low temperature drying system and method suitable for natural rubber, system includes rubber pump, vibrating conveyor, net belt is dryer and vacuum drying device.The drying method includes the following steps: pumping, natural rubber material is pumped out to drying system by rubber pump;Centrifugal dewatering, material is transported to centrifuge by vibrating conveyor and is centrifugally dewatered;Hot air drying, after centrifugal dewatering, material is transported to net belt dryer by vibrating conveyor and is heated to remove surface water;Vacuum drying, after heating to remove surface water, material is sent into vacuum drying device, and material is vacuum low temperature dried by being imported medium with high temperature into vacuum drying device, after drying, medium is discharged to material and is cooled then discharged;Weighing and packing, discharge is weighed and packed.The drying system integrates the advantages of pre-dewatering and several drying methods, reduces drying temperature, shortens drying time, maintains the quality and performance of rubber, and improves product quality.

Description

Technical Field

[0001] This invention relates to the field of drying natural rubber, and in particular to a low-temperature drying system and method suitable for natural rubber. Background Technology

[0002] After harvesting, natural rubber requires primary processing, which generally includes the latex line, wet line, and dry line. The wet line process mainly includes a series of operations such as crushing, soaking, extrusion washing, creping, shredding, pelletizing, drying, weighing, packaging, and sampling for grading. Among these, drying is the key step in the primary processing of natural rubber. The tunnel-type hot air drying cabinet currently used in the industry is an essential piece of equipment for most primary processing plants at home and abroad. However, it has high energy consumption, large footprint, and low automation. Current drying equipment adopts a hot air deep bed drying mode. The wet rubber granules (moisture content ≤40%) formed by the shredder in the "wet line" are piled up to a height of more than 350mm after loading. In order to improve drying efficiency, a relatively high drying temperature (120±3℃) is generally used. However, because the temperature is difficult to control, it is easy to approach the critical temperature of 129℃ for molecular chain breakage. Therefore, the temperature and humidity of hot air drying are difficult to control, resulting in low drying efficiency. Moreover, natural rubber is easily affected by oxidation during the open drying process, leading to a decline in rubber quality. Because natural rubber is a poor conductor of heat and has strong self-adhesion during initial processing, hot air drying is inefficient and prone to quality problems such as stickiness, underdeveloped rubber, and thermal-oxidative degradation, which are detrimental to product performance. Drying has become a prominent problem restricting the development of the industry.

[0003] To improve the drying efficiency of natural raw rubber, enhance product quality, improve process stability, control costs, and reduce environmental pollution, it is necessary to study the drying process and key equipment for wet natural raw rubber granules in conjunction with energy utilization methods, and explore new drying modes that are easy to promote and apply industrially. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a low-temperature drying system and method suitable for natural rubber. It integrates the advantages of pre-dehydration and several drying methods, reducing drying temperature, shortening drying time, and allowing for adjustable and controllable drying parameters. This effectively improves upon the prominent problems of under-drying and thermo-oxidative degradation inherent in traditional drying methods, thereby enhancing product quality, drying efficiency, and process stability. Specifically, the objective of this invention is achieved as follows:

[0005] A low-temperature drying system suitable for natural rubber, comprising:

[0006] The rubber pump draws natural rubber material into the drying system;

[0007] Vibrating conveyors are used to transport materials using vibration, achieving solid-liquid separation.

[0008] Centrifuges are used to initially remove surface water from materials;

[0009] A mesh belt dryer includes a mesh belt conveyor and a hot air system; the hot air system heats and dries the material passing through the mesh belt conveyor.

[0010] A vacuum drying device includes a support frame, a housing, and a spiral lifting section. The housing is a sealed chamber mounted on the support frame. The housing includes a feed inlet and a vacuum outlet at the top of the housing, and a discharge outlet at the bottom of the housing. Valves are installed at the feed inlet and the discharge outlet. A hollow interlayer is provided on the outer wall of the housing, and a heat medium is introduced into the hollow interlayer to heat the material inside the housing. The spiral lifting section is vertically installed inside the housing and is used to lift the material inside the housing from the bottom to the top.

[0011] Furthermore, the spiral lifting section includes a stirring shaft, spiral blades, a sleeve, and a rotating shaft motor; the stirring shaft is rotatably and vertically installed inside the housing, and the spiral blades are installed on the outer surface of the stirring shaft; the rotating shaft motor is installed on the top of the housing, and the output end of the rotating shaft motor is connected to the upper end of the stirring shaft, enabling the stirring shaft to rotate; the sleeve is fixedly installed on the top of the housing through several spaced connecting rods, and the sleeve body is fitted over the outer edge of the spiral blades; a separation section is installed inside the sleeve, which can separate materials that are stuck together when the material is lifted by the spiral blades.

[0012] Furthermore, the separation section includes a tearing section and a cutting section; the tearing section is toothed, with the tooth tips vertically downward and installed at the bottom of the cylinder; the cutting section includes a fixed blade installed on the inner wall of the upper end of the sleeve; the fixed blade includes a blade holder and a blade body; the blade holder is fixedly installed against the inner wall of the sleeve and is used to support the blade body; the blade body is plate-shaped, with a trapezoidal surface, and its lower bottom edge is connected to the blade holder and supported in the blade holder; the blade body is inclined in the direction of rotation of the stirring shaft and forms a certain angle with the horizontal plane; when the spiral blade lifts the material through the sleeve, the tearing section can tear the material, and the cutting section can cut the material.

[0013] Furthermore, the housing includes an upper housing and a lower housing; the upper housing is cylindrical, and the lower housing is an inverted frustum shape. The upper surface of the lower housing has the same diameter as the lower surface of the upper housing, and the upper housing and the lower housing are fixedly connected and installed; a heat medium inlet is provided at the bottom of one side of the upper housing, and a heat medium outlet is provided at the top of the opposite side; a heat medium inlet is provided at the bottom of one side of the lower housing, and a heat medium outlet is provided at the top of the opposite side; the heat medium inlet and the heat medium outlet allow the heat medium to pass through the hollow interlayer between the upper housing and the lower housing.

[0014] Furthermore, the stirring shaft has a double-layer tube structure. The bottom of the inner tube has a connecting port that connects to the outer tube, the top of the inner tube has a heat medium inlet, and the top side of the outer tube has a heat medium outlet. Through the heat medium inlet and the heat medium outlet, the heat medium can enter from the inner tube of the stirring shaft, enter the outer tube, and then be discharged.

[0015] A low-temperature drying method suitable for natural rubber includes the following steps:

[0016] S1 pumping pumps natural rubber material into the drying system via a rubber pump.

[0017] S2 centrifugal dewatering involves conveying materials to a centrifuge via a vibrating conveyor for centrifugal dewatering.

[0018] S3 hot air drying involves conveying the centrifugally dehydrated material to a mesh belt dryer via a vibrating conveyor for heating and surface water removal, as well as preheating the material. This allows the material to enter the dehydration and drying process more quickly in the next stage and further prevents the material from sticking together into large clumps, thus avoiding affecting the subsequent drying efficiency and effect.

[0019] S4 vacuum drying involves heating the material after removing surface moisture and then feeding it into a vacuum drying device. The material is dried in a vacuum at low temperature by introducing a medium at a temperature higher than that of the material. After drying, the medium is discharged to cool the material before it is discharged. The final output is irregular particles or small blocks, which facilitates precise weighing and packaging.

[0020] The S5 weighs and packages the output material.

[0021] Vibrating conveyors enable preliminary solid-liquid separation of materials.

[0022] Furthermore, the centrifugal dehydration process in step S2 is less than or equal to 2 minutes to prevent the material from sticking together; the moisture content of the material after centrifugation in step S2 is less than or equal to 35%.

[0023] Furthermore, the material discharge temperature after hot air drying in step S3 is 60°C to 70°C; the air temperature for hot air drying in step S3 is 70°C to 75°C; and the drying time of the material in step S3 is less than or equal to 30 minutes.

[0024] Furthermore, in step S4, the temperature of the medium introduced into the vacuum drying device during vacuum drying is less than or equal to 85°C; the time for vacuum drying the material in step S4 is less than or equal to 210 minutes; and the discharge temperature of the material after vacuum drying in step S4 is less than or equal to 60°C, and the moisture content is less than or equal to 2%.

[0025] Furthermore, the material after hot air drying in step S3 is conveyed by an elevator to a vibrating conveyor and then into a vacuum drying device for step S4 vacuum drying. The vibrating conveyor is equipped with several diversion ports, each corresponding to a vacuum drying device. Although the material after hot air drying in S3 is more conducive to vacuum drying in S4, it is prone to cooling and forming self-adhesive clumps if it is not immediately put into the next stage of vacuum drying. Therefore, multiple diversion ports are provided with multiple vacuum drying devices for emergency output.

[0026] The beneficial effects of this invention are as follows:

[0027] (i) Compared with existing technologies, the advantages of using this drying system, which integrates pre-dehydration and several drying methods, are that it reduces the drying temperature, shortens the drying time, and allows for precise control of drying parameters at each stage; it can dry natural rubber materials at relatively low temperatures, accelerates moisture evaporation, avoids thermal oxidation and decomposition of rubber at high temperatures, maintains the quality and performance of rubber, effectively improves the prominent problems of under-drying and thermal-oxidative degradation in traditional drying, and improves product quality, drying efficiency and process stability.

[0028] (ii) Furthermore, due to the strong adhesive properties of natural rubber, traditional drying methods often result in large lumps of material in the final stage, requiring manual intervention for counterweighting during packaging. In this system, the final vacuum drying stage utilizes a spiral lifting mechanism to elevate, tear, and cut the material, preventing it from caking into lumps and allowing for better heating and drying, thus improving drying efficiency. This also alters the output form of the dried material, facilitating subsequent packaging.

[0029] (iii) Vacuum negative pressure drying can be carried out in a relatively closed environment, reducing the contact between oxygen and pollutants, thereby avoiding the oxidation and contamination of rubber. This helps to improve the quality and purity of rubber.

[0030] (iv) Compared to traditional hot air drying methods, negative pressure drying requires less energy. Because the boiling point of water decreases under negative pressure, drying can be carried out at lower temperatures, thus reducing energy consumption. This aligns with the green, low-carbon, energy-saving, and environmentally friendly industrial development direction, and promotes the high-quality development of the natural rubber primary processing industry.

[0031] (v) The subdivision of the drying process section enables continuous production, improves the level of automation, significantly reduces the number of workers, and reduces labor intensity. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the system described in this invention;

[0033] Figure 2 This is a schematic diagram of the system described in this invention from another angle;

[0034] Figure 3 This is the main view of the system described in this invention;

[0035] Figure 4 This is a top view of the system described in this invention;

[0036] Figure 5 This is a schematic diagram of the system workflow described in this invention;

[0037] Figure 6 This is a schematic diagram of the working process of the vacuum drying device in the system described in this invention;

[0038] Figure 7 This is a three-dimensional structural diagram of the mesh belt dryer described in this invention;

[0039] Figure 8 This is a three-dimensional structural diagram of the mesh belt dryer described in this invention from another angle;

[0040] Figure 9 This is a front view of the mesh belt dryer described in this invention;

[0041] Figure 10 This is a rear view of the mesh belt dryer described in this invention;

[0042] Figure 11 This is a left view of the mesh belt dryer described in this invention;

[0043] Figure 12 This is a top view of the mesh belt dryer described in this invention;

[0044] Figure 13 This is a perspective view of the overall structure of the vacuum drying device described in this invention;

[0045] Figure 14 This is a perspective view of the internal structure of the vacuum drying device described in this invention;

[0046] Figure 15 This is a front cross-sectional view of the vacuum drying apparatus described in this invention;

[0047] Figure 16 This is a front cross-sectional view of the interior of the housing of the vacuum drying device described in this invention under operating conditions;

[0048] Figure 17 This is a schematic diagram of the fixed blade structure in the vacuum drying apparatus of the present invention;

[0049] In the picture:

[0050] 1—Glue pump; 2—Vibrating conveyor; 3—Centrifuge;

[0051] 4—Belt dryer; 41—Dryer support; 42—Conveyor belt; 43—Drive roller; 44—Belt motor; 45—Heat pump; 46—Air duct; 47—Steam separator; 48—Air hood; 49—Air supply duct; 410—Return air duct.

[0052] 5—Vacuum drying device; 51—Spiral lifting section; 511—Stirring shaft; 512—Spiral blade; 513—Sleeve; 5131—Tearing section; 5132—Fixed blade; 5133—Connecting rod; 5134—Blade holder; 5135—Blade body; 514—Rotating shaft motor; 52—Housing shell; 521—Upper housing; 522—Lower housing; 523—Feed inlet; 524—Discharge outlet; 525—Vacuum port; 53—Support; 54—Heat medium inlet; 55—Heat medium outlet. Detailed Implementation

[0053] To make the technical means, inventive features, and objectives of this invention easier to understand, the technical solution of this invention will be further described below with reference to one embodiment of a low-temperature drying system and drying method suitable for natural rubber and specific implementation methods.

[0054] like Figure 1-17 As shown, specific embodiments of the present invention are as follows:

[0055] A low-temperature drying system for natural rubber includes a rubber pump (1), a vibrating conveyor (2), an elevator, a belt conveyor, a centrifuge (3), a feeder, a mesh belt dryer (4), and a vacuum drying device (5).

[0056] The mesh belt dryer (4) includes a mesh belt conveyor, an air supply channel (49), a multi-functional heat pump (45), an air duct (46), a return air duct (410), and a steam-water separator (47).

[0057] The mesh belt conveyor includes a dryer support (53)(41), a conveyor mesh belt (42), a drive roller (43), a mesh belt motor (44), and a fan shroud (48). The drive roller (43) is rotatably mounted on the dryer support (53)(41), and the conveyor mesh belt (42) is sleeved on the drive roller (43). The mesh belt motor (44) is fixedly connected to the dryer support (53)(41), and the output end of the mesh belt motor (44) is connected to the drive roller (43). The mesh belt motor (44) can drive the drive roller (43) to rotate, thereby driving the conveyor mesh belt (42) to move. The mesh belt conveyor is used to transport natural rubber materials. The air supply channel (49) is installed below the conveyor mesh belt (42) of the mesh belt conveyor, with the air outlet opening in the direction of ... The heat pump (45) can deliver hot air into the air supply channel (49); the air supply channel (49) can dry the material conveyed on the conveyor belt (42) with hot air. The air guide pipe (46) is "n" shaped; the "n" shaped air guide pipe (46) is installed above the conveyor belt (42), with one end being the air guide inlet and the other end being the air guide outlet; the air guide inlet is located above the air supply port opening. The air guide outlet is located upstream of the conveyor belt (42) relative to the air guide inlet. An exhaust pump is installed between the air guide outlet and the air guide inlet to draw the air from one end of the air guide inlet to the end of the air guide outlet. The air hood (48) is mounted on the dryer support (53)(41), with two guide ports on the top, which are fixedly connected to the air guide inlet and the air guide outlet respectively; the air hood (48) has an inlet (523) on the top of the feed end of the conveyor belt (42), and an outlet (524) on the other end. The conveyor belt (42) includes a conveying section and an unloaded section. The conveying section is located inside the hood (48), and the unloaded section is located outside the hood (48). A return air duct (410) is installed below the conveyor belt (42). The return air inlet of the return air duct (410) faces upwards and is located below the air outlet. The return air outlet of the return air duct (410) is connected to the multi-functional heat pump (45) to provide return air to the multi-functional heat pump (45). A vapor-water separator (47) is also installed between the return air outlet of the return air duct (410) and the multi-functional heat pump (45), which can separate the vapor and water in the return air. The multi-functional heat pump (45) is equipped with a condensate drain outlet to discharge the condensate in the return air.

[0058] The vacuum drying device (5) includes a triangular support (53), a shell (52), and a spiral lifting part (51). The triangular support (53) is used to support the shell (52). The shell (52) is mounted on the triangular support (53). The shell (52) is a sealed chamber with a hollow interlayer on its outer wall. A heat medium is introduced into the hollow interlayer to heat the material inside the shell (52). The shell (52) includes an upper shell (521) and a lower shell (522). The upper shell (521) is cylindrical, and the lower shell (522) is an inverted frustum. The upper surface of the lower shell (522) has the same diameter as the lower surface of the upper shell (521). The upper shell (521) and the lower shell (522) are fixedly connected and installed. The upper shell (521) has a feed inlet (523) and a vacuum port (525) at the top; the lower shell (522) has a discharge port (524) at the bottom; the feed inlet (523) and the discharge port (524) are equipped with pneumatic eccentric hemispherical valves. The upper shell (521) has a heat medium inlet (54) at the bottom of one side and a heat medium outlet (55) at the top of the opposite side; the lower shell (522) has a heat medium inlet (54) at the bottom of one side and a heat medium outlet (55) at the top of the opposite side; the heat medium can pass through the hollow interlayer of the upper shell (521) and the lower shell (522) through the heat medium inlet (54) and the heat medium outlet (55).

[0059] The spiral lifting section (51) is vertically installed inside the housing (52) to lift the material inside the housing (52) from the bottom to the top. The spiral lifting section (51) includes a stirring shaft (511), spiral blades (512), a sleeve (513), and a rotating shaft motor (514); the stirring shaft (511) is rotatably and vertically installed inside the housing (52) and is coaxial with the upper and lower housings (522). Spiral blades (512) are installed on the outer surface of the stirring shaft (511); a rotating shaft motor (514) is installed on the top of the upper housing (521), and the output end of the rotating shaft motor (514) is connected to the upper end of the stirring shaft (511) to drive the stirring shaft (511) to rotate; the stirring shaft (511) is a double-layer tube structure, with a connecting port at the bottom of the inner tube to connect with the outer tube, a heat medium inlet (54) at the top of the inner tube, and a heat medium outlet (55) on one side of the top of the outer tube. Through the heat medium inlet (54) and the heat medium outlet (55), the heat medium can enter from the inner tube of the stirring shaft (511) and then enter the outer tube before being discharged. The sleeve (513) is fixedly installed inside the top of the housing (52) by a number of spaced connecting rods (5133). The sleeve (513) is sleeved on the outer edge of the spiral blade (512). A separation part is installed inside the sleeve (513). When the material is lifted by the spiral blade (512), the separation part can separate the materials that are stuck together.

[0060] The separation section includes a tearing section (5131) and a cutting section; the tearing section (5131) is toothed with the tooth tips pointing vertically downwards and installed at the bottom of the cylinder; the cutting section includes a fixed blade (5132) installed on the inner wall of the upper end of the sleeve (513); the fixed blade (5132) includes a blade holder (5134) and a blade body (5135); the blade holder (5134) is fixedly installed against the inner wall of the sleeve (513) and is used to support the blade body (5135); the blade body (5135) is plate-shaped with a trapezoidal surface and its lower bottom edge is connected to the blade holder (5134) and supported in the blade holder (5134); the blade body (5135) is inclined in the direction of rotation of the stirring shaft (511) and forms a certain angle with the horizontal plane; when the spiral blade (512) lifts the material through the sleeve (513), the tearing section (5131) can tear the material and the cutting section can cut the material.

[0061] A rubber pump (1) is set at the front end of the system to draw the natural rubber material to be dried into the drying system; the moisture content of the incoming material is greater than or equal to 40%. Then it is conveyed to the elevator by a vibrating conveyor (2), and after being lifted, it is sent to the centrifuge (3) by a belt conveyor for centrifugal dehydration; the centrifugal dehydration process is less than or equal to 2 minutes; the moisture content of the material after the centrifugal treatment is less than or equal to 35%. The centrifuged material is sent to the mesh belt dryer (4) for hot air drying by the vibrating conveyor (2) and the feeder. The discharge temperature of the material after the hot air drying is 60℃ to 70℃; the air temperature of the hot air drying is 70℃ to 75℃; the time of the material after the hot air drying is less than or equal to 30 minutes. The hot air dried material is sent to the vacuum drying device (5) for vacuum drying by the feeder and the vibrating conveyor (2). Here, the vibrating conveyor (2) is set with several diversion ports, each diversion port corresponding to a vacuum drying device (5). Vacuum drying includes a vacuum low temperature drying stage and a vacuum cooling stage. During the vacuum drying stage, the temperature of the medium introduced into the vacuum drying device (5) is less than or equal to 85°C; the processing time of the material in the vacuum drying stage is less than or equal to 210 minutes; then the material enters the vacuum cooling stage, and the discharge temperature of the material after vacuum drying is less than or equal to 60°C, and the moisture content is less than or equal to 2%. After cooling, the material is discharged and weighed and packaged by a belt conveyor. The vibrating conveyor (2) can realize solid-liquid separation of the material while vibrating and conveying it; a water collection hopper is set below the vibrating conveyor (2). The centrifuge (3) is used to initially remove surface water from the material.

[0062] In the vacuum drying stage, the material is fed into the chamber of the vacuum drying apparatus for drying. The air inside the shell (52) is extracted through the vacuum port (525). A heat medium at a temperature of less than or equal to 85°C is introduced into the walls of the vacuum chamber and the stirring shaft (511) of the spiral lifting part (51) to heat the material inside the chamber. During drying, the material is lifted from the bottom of the chamber to the top of the chamber and then allowed to fall naturally, and this process is repeated. During the lifting process, the toothed tearing part (5131) at the bottom of the sleeve (513) of the spiral lifting part (51) is used to tear the material entering the sleeve (513). When the material leaves the upper part of the sleeve (513), it is cut by the fixed blade (5132) on the inner wall of the upper end of the sleeve (513). After the drying process is completed, the pneumatic eccentric hemispherical valve of the discharge port (524) at the bottom of the lower shell (522) is opened to discharge the material.

[0063] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A low-temperature drying system suitable for natural rubber, characterized in that, include: The rubber pump (1) draws natural rubber material into the drying system; Vibrating conveyor (2) conveys materials by vibration to achieve solid-liquid separation; Centrifuge (3) is used to initially remove surface water from materials; The mesh belt dryer (4) includes a mesh belt conveyor and a hot air system; the hot air system heats and dries the material passing through the mesh belt conveyor. The vacuum drying device (5) includes a support (53), a housing (52), and a spiral lifting part (51); the housing (52) is a sealed chamber, which is installed on the support (53). The housing (52) includes a feed inlet (523) and a vacuum port (525) located at the top of the housing (52) and a discharge port (524) located at the bottom of the housing (52); valves are installed on the feed inlet (523) and the discharge port (524); a hollow jacket is provided on the outer wall of the housing (52), and a heat medium is introduced into the hollow jacket to heat the material inside the housing (52); the spiral lifting part (51) is vertically installed inside the housing (52) and is used to lift the material inside the housing (52) from the bottom to the top. The spiral lifting section (51) includes a stirring shaft (511), spiral blades (512), a sleeve (513), and a rotating shaft motor (514). The stirring shaft (511) is rotatably and vertically installed inside the housing (52), and the spiral blades (512) are installed on the outer surface of the stirring shaft (511). The rotating shaft motor (514) is installed on the top of the housing (52), and the output end of the rotating shaft motor (514) is connected to the upper end of the stirring shaft (511) to drive the stirring shaft (511) to rotate. The sleeve (513) is fixedly installed inside the top of the housing (52) by several spaced connecting rods (5133), and the sleeve (513) is sleeved on the outer edge of the spiral blades (512). A separation section is installed inside the sleeve (513), which can separate materials that are stuck together when the material is lifted by the spiral blades (512). The separation section includes a tearing section (5131) and a cutting section; the tearing section (5131) is toothed, with the tooth tips vertically downward and installed at the bottom of the sleeve (513); the cutting section includes a fixed blade (5132) installed on the inner wall of the upper end of the sleeve (513); the fixed blade (5132) includes a blade holder (5134) and a blade body (5135); the blade holder (5134) is fixedly installed against the inner wall of the sleeve (513) and is used for support. Blade (5135); The blade (5135) is sheet-shaped with a trapezoidal surface and its bottom edge is connected to the blade holder (5134) and mounted in the blade holder (5134); The blade (5135) is inclined in the direction of rotation of the stirring shaft (511) and forms a certain angle with the horizontal plane; When the spiral blade (512) lifts the material through the sleeve (513), the tearing part (5131) can tear the material, and the cutting part can cut the material.

2. The low-temperature drying system for natural rubber as described in claim 1, characterized in that: The housing (52) includes an upper housing (521) and a lower housing (522); the upper housing (521) is cylindrical, and the lower housing (522) is an inverted frustum shape. The upper surface of the lower housing (522) has the same diameter as the lower surface of the upper housing (521). The upper housing (521) and the lower housing (522) are fixedly connected and installed. A heat medium inlet (54) is provided at the bottom of one side of the upper housing (521), and a heat medium outlet (55) is provided at the top of the opposite side. A heat medium inlet (54) is provided at the bottom of one side of the lower housing (522), and a heat medium outlet (55) is provided at the top of the opposite side. The heat medium can pass through the hollow interlayer of the upper housing (521) and the lower housing (522) through the heat medium inlet (54) and the heat medium outlet (55).

3. The low-temperature drying system for natural rubber as described in claim 1, characterized in that: The stirring shaft (511) has a double-layer tube structure. The bottom of the inner tube is connected to the outer tube. The top of the inner tube is provided with a heat medium inlet (54). The top side of the outer tube is provided with a heat medium outlet (55). Through the heat medium inlet (54) and the heat medium outlet (55), the heat medium can enter from the inner tube of the stirring shaft (511) and then enter the outer tube and then be discharged.

4. A low-temperature drying method for natural rubber based on the drying system of claim 1, characterized in that, Includes the following steps: S1 pumping: Natural rubber material is pumped out to the drying system via the rubber pump (1); S2 centrifugal dehydration: The material is conveyed to the centrifuge (3) by a vibrating conveyor (2) for centrifugal dehydration; S3 hot air drying: the centrifugally dehydrated material is conveyed to the mesh belt dryer (4) by a vibrating conveyor (2) for heating and surface water removal; S4 Vacuum drying: The material after heating and removing surface water is sent into the vacuum drying device (5). The material is vacuum dried at low temperature by introducing a medium with a temperature higher than that of the material into the vacuum drying device (5). After drying, the medium is discharged to cool the material and then the material is discharged. During vacuum drying, the material is torn by the toothed tearing part (5131) provided at the bottom of the sleeve (513) of the spiral lifting part (51) during the lifting process. When the material leaves the upper part of the sleeve (513), it is cut by the fixed blade (5132) provided on the inner wall of the upper end of the sleeve (513). The S5 weighs and packages the output material.

5. The low-temperature drying method for natural rubber as described in claim 4, characterized in that: The centrifugation and dehydration process in step S2 shall be less than or equal to 2 minutes; the moisture content of the material after centrifugation in step S2 shall be less than or equal to 35%.

6. The low-temperature drying method for natural rubber as described in claim 4, characterized in that: The material discharge temperature after hot air drying in step S3 is 60℃ to 70℃; the air temperature of hot air drying in step S3 is 70℃ to 75℃; and the time of hot air drying in step S3 is less than or equal to 30 minutes.

7. The low-temperature drying method for natural rubber as described in claim 4, characterized in that: The temperature of the medium introduced into the vacuum drying device (5) during step S4 vacuum drying is less than or equal to 85°C; the time for vacuum drying of the material in step S4 is less than or equal to 210 minutes; the discharge temperature of the material after vacuum drying in step S4 is less than or equal to 60°C, and the moisture content is less than or equal to 2%.

8. A low-temperature drying method for natural rubber as described in claim 4, characterized in that: After hot air drying in step S3, the material is conveyed to the vibrating conveyor (2) by the elevator, and then enters the vacuum drying device (5) for vacuum drying in step S4. The vibrating conveyor (2) is equipped with several diversion ports, and each diversion port corresponds to a vacuum drying device (5).

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