A feeding device for polyurethane material preparation and a method of using the same

Abstract

The application belongs to the technical field of feeding devices, and discloses a feeding device for polyurethane material preparation and a use method thereof. The device comprises an upper cover plate, a partition cavity type feeding shell is fixedly installed on the bottom surface of the upper cover plate, a middle cavity and cylindrical material cavities located on the left and right sides of the middle cavity are arranged in the partition cavity type feeding shell, an auger pushing structure is installed in the cylindrical material cavities, two electric heating pipes and a temperature sensor are symmetrically installed in the middle cavity, and unidirectional discharging structures are installed at the two outlets at the bottom end of the partition cavity type feeding shell. A T-shaped material pipe is installed at an upper position in the middle cavity, a heating unit is installed at the inlet end of the T-shaped material pipe and communicates with an external isocyanate source, and the two outlet ends of the T-shaped material pipe respectively communicate with the corresponding cylindrical material cavities. A double-belt driving unit for driving the rotation of the two auger pushing structures is arranged above the upper cover plate. The application can maintain the feeding operation of isocyanate and guarantee the continuity of production.

Description

Technical Field

[0001] This invention belongs to the field of feeding device technology, specifically, it relates to a feeding device for preparing polyurethane materials and its usage method. Background Technology

[0002] As one of the core raw materials for polyurethane synthesis, isocyanate requires a dedicated feeding device for precise and safe delivery during the preparation process. The feeding device stably and quantitatively delivers isocyanate from the storage container to the reactor and mixes it with other components (such as polyols) at the appropriate time and in the appropriate proportion. Because isocyanate is sensitive to moisture, has high reactivity, and has certain toxicity and corrosiveness, the feeding device must have special capabilities for sealing, drying, leak prevention, and chemical corrosion resistance.

[0003] The feeding process begins when a production signal triggers the closure of the return valve and the opening of each injection valve. Each injection valve then injects polyols, catalysts, chain extenders, isocyanates, and other raw materials into the reactor according to the production process requirements using high-pressure jets. These raw materials react together with other pre-added or simultaneously added components. During the shutdown phase, the nozzles are closed to stop the feeding operation, and the reactor awaits the next instruction.

[0004] The existing isocyanate feeding device used in the above process employs a double-spiral injection valve. While this valve controls the flow of isocyanate during polyurethane preparation, its control over the conveying temperature is poor. This easily leads to isocyanate crystallizing and precipitating as a solid due to temperatures below its freezing point. Furthermore, during prolonged conveying or when the isocyanate remains in dead zones or gaps, it undergoes self-polymerization, forming gels or hard solids. This is because the double-spiral injection valve has a complex structure with irregular shapes of the valve body and spiral shaft, making it difficult for the heating system to evenly cover all surfaces. This results in low-temperature zones on the tooth surface, at the root of the journal, and in the corners of the valve cavity. When isocyanate flows through these low-temperature zones, heat is rapidly absorbed, and the local liquid temperature may drop below the freezing point, causing crystals to precipitate on the spiral tooth surface or the inner wall of the valve cavity. In such cases, it is necessary to stop the machine for heating and melting or disassemble and clean it, reducing its effectiveness. Summary of the Invention

[0005] The purpose of this invention is to provide a feeding device and its method for preparing polyurethane materials. Before feeding, the heating unit at the T-shaped feed pipe inlet and the electric heating tube in the diaphragm-type feeding shell are turned on. The temperature of the middle cavity is monitored by a temperature sensor. After the entire feeding device is heated to 40-45°C, the external isocyanate is introduced into the left and right cylindrical material cavities of the diaphragm-type feeding shell through the T-shaped feed pipe. When feeding begins, the double belt drive unit drives the auger pushing structure in the two sets of cylindrical material cavities to rotate, pushing the isocyanate into the reactor through the one-way discharge structure, thereby solving the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A feeding device for preparing polyurethane materials includes an upper cover plate. A cavity-type feeding shell is fixedly installed on the bottom surface of the upper cover plate. The cavity-type feeding shell has a central cavity and cylindrical material cavities located on the left and right sides of the central cavity. The cylindrical material cavities are equipped with auger pusher structures for pushing isocyanate towards the discharge port. Two electric heating tubes are symmetrically installed inside the central cavity. Temperature sensors are installed in the central cavity above the two electric heating tubes. One-way discharge structures are installed at the bottom of the cavity-type feeding shell at the outlets of the two cylindrical material cavities. A T-shaped material tube is installed at the upper part of the central cavity. A heating unit is installed at the inlet end of the T-shaped material tube and is connected to an external isocyanate source. The two outlet ends of the T-shaped material tube are respectively connected to the corresponding cylindrical material cavities on the left and right sides. A double belt drive unit is arranged above the upper cover plate. The power output end of the double belt drive unit is connected to the two auger pusher structures.

[0007] The following are further optimizations of the above technical solution by the present invention: The heating unit includes a hollow chamber fixedly installed at the feed inlet of the T-shaped material pipe. An electric heating tube is installed inside the hollow chamber, which is made of aluminum alloy.

[0008] Further optimization: A sealing gasket is provided between the upper cover plate and the cavity-type feeding shell, and a top shell is installed on the top of the upper cover plate.

[0009] Further optimization: The auger pushing structure includes a solid auger spiral shaft rotatably installed in the cylindrical material cavity. The upper end of the solid auger spiral shaft passes through the upper cover plate and extends above the upper cover plate. A sealed bearing is installed at the connection between the upper cover plate and the solid auger spiral shaft. A gap is left between the blade edge of the solid auger spiral shaft and the inner wall of the cylindrical material cavity.

[0010] Further optimization: The one-way discharge structure consists of a one-way valve and a feeding pipe. The one-way valve is coaxially arranged with the solid auger spiral shaft and installed on the discharge port of the cavity-type feeding shell. The feeding pipe is fixedly installed on the discharge end of the one-way valve.

[0011] Further optimization: The left and right sides of the back of the cavity-type feeding shell are integrally formed with perforated brackets, the middle cavity is filled with heat-conducting oil, and the electric heating tube is immersed in the heat-conducting oil.

[0012] Further optimization: The dual-belt drive unit includes a double-layer frame fixed at the center of the top of the upper cover plate. A vertically arranged main shaft is rotatably mounted on the double-layer frame. Two sets of synchronous belt pulley transmission structures are installed at intervals along the axial direction on the main shaft. The other end of the two sets of synchronous belt pulley transmission structures is respectively connected to the upper end of the corresponding solid auger spiral shaft. A reduction motor for driving the rotation of the main shaft is installed on the upper cover plate.

[0013] Further optimization: A downward-extending recessed cavity is provided at the center of the top of the upper cover plate, and the reduction motor is fixedly installed in the recessed cavity.

[0014] Further optimization: A controller is installed at the rear of the top of the upper cover plate. The controller is electrically connected to the electric heating tube, the heating unit, the temperature sensor, and the dual belt drive unit.

[0015] The present invention also provides a method of using a feeding device for preparing polyurethane materials, comprising the following steps: S1: The controller issues a command to start the heating unit and electric heating tube one. The heating unit initially heats the feed inlet section of the T-shaped material tube, and electric heating tube one directly heats the central cavity and the cylindrical material cavities on the left and right sides that are closely attached to it. The temperature sensor monitors the temperature of the central cavity in real time and feeds it back to the controller. The controller has a set threshold, which is 40℃ to 45℃. When the temperature sensor detects that the temperature of the central cavity is lower than this range, the controller starts the heating unit and electric heating tube one to perform heating operation. After the set temperature is reached, the controller switches to intermittent heating or enters the heat preservation mode, so that the metal inner wall of the cavity feeding shell is uniformly heated to the liquid flow temperature required by isocyanate. S2: After preheating is completed, the isocyanate in the external storage tank is introduced into the cylindrical material cavities on the left and right sides through the T-shaped material pipe under the pressure of nitrogen and driven by the upstream pump. The isocyanate gradually fills the cylindrical material cavities on the left and right sides. At this time, the screw conveyor pusher structure is in a static state. The material in the cylindrical material cavity remains in a liquid state and will not solidify because the overall temperature is maintained between 40-45℃. S3: When feeding is required, the controller sends a start command to the dual belt drive unit, causing the auger pusher structure to start rotating. Its spiral blades push the isocyanate in the cylindrical material chamber toward the discharge port. The liquid isocyanate is extruded from the unidirectional discharge structure and injected into the downstream reactor. The left and right material chambers work at the same time, achieving double the output of feeding and serving as backups for each other. S4: When feeding ends, the system enters the stop and standby stage. The controller receives a stop signal and cuts off the power of the dual belt drive unit, causing the auger pusher structure to stop rotating. At this time, the material in the cylindrical material chambers on the left and right sides no longer moves forward, and due to the cut-off effect of the one-way discharge structure, the gas and moisture in the reactor cannot flow back into the cylindrical material chamber.

[0016] The present invention, by adopting the above technical solution, has at least the following beneficial effects: 1. This invention solves the problems of poor temperature control, crystallization blockage, self-polymerization and solidification, and frequent maintenance of existing feeding devices by preheating homogenization, flow channel simplification, power drive optimization and unidirectional discharge.

[0017] 2. In this invention, the heating unit inside the T-shaped feed tube and the electric heating tube in the cavity of the partitioned feed shell are simultaneously turned on before feeding, and the entire feeding device is uniformly preheated to 40-45°C by closed-loop feedback from the temperature sensor. This ensures that all metal surfaces in contact with the material are above the isocyanate freezing point, reducing the risk of crystal precipitation and blockage caused by heating blind spots or local overcooling in traditional solutions. Secondly, the left and right symmetrically arranged cylindrical feed cavities are combined with the auger pushing structure, resulting in a simple and straight flow channel. The material is continuously pushed along the axial direction. When feeding stops, the unidirectional discharge structure immediately cuts off and isolates the moisture in the reactor, making it difficult for crystal precipitation to occur in the feed cavity. This inhibits the slow self-polymerization of isocyanate in gaps and dead corners, preventing the formation of gels or hard solids. Finally, the dual belt drive unit and the left and right symmetrical cylindrical feed cavities achieve dual-path synchronous conveying. The two chambers are isolated but work synchronously. Even if one side is slightly blocked due to an accident, the other side can still maintain feeding operation, ensuring production continuity. Attached Figure Description

[0018] Figure 1 This is a perspective view of the overall structure in an embodiment of the present invention; Figure 2 This is a front sectional view of the overall structure in an embodiment of the present invention; Figure 3 This is a three-dimensional sectional view of the overall structure in an embodiment of the present invention. Figure 1 ; Figure 4 This is a three-dimensional sectional view of the overall structure in an embodiment of the present invention. Figure 2 ; Figure 5 This is a three-dimensional cross-sectional view of the cavity-type feeding shell in an embodiment of the present invention. Figure 1 ; Figure 6 This is a three-dimensional cross-sectional view of the cavity-type feeding shell in an embodiment of the present invention. Figure 2 ; Figure 7 This is a schematic diagram of the structure of the dual-belt drive unit in an embodiment of the present invention; Figure 8 This is a schematic diagram of the cavity-type feeding shell in an embodiment of the present invention.

[0019] In the diagram: 1-Upper cover plate; 101-Top shell; 102-Submerged cavity; 2-Bridging feeding shell; 21-Cylindrical material cavity; 22-Middle cavity; 3-Auger pushing structure; 31-Sealed bearing; 32-Solid auger spiral shaft; 4-T-shaped material pipe; 5-One-way discharge structure; 51-One-way valve; 52-Feeding pipe; 6-Electric heating tube one; 7-Heating unit; 71-Hollow chamber; 72-Electric heating tube two; 8-Temperature sensor; 9-Double belt drive unit; 91-Reduction motor; 92-Double-layer frame; 93-Main shaft; 94-Synchronous belt pulley transmission structure; 10-Controller. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] Depend on Figures 1 to 3 As shown, a feeding device for preparing polyurethane materials includes an upper cover plate 1. A cavity-type feeding shell 2 is fixedly installed on the bottom surface of the upper cover plate 1. The cavity-type feeding shell 2 has a central cavity 22 and cylindrical material chambers 21 located on the left and right sides of the central cavity 22. An auger pusher structure 3 for pushing isocyanate towards the discharge port is installed inside the cylindrical material chambers 21. Two electric heating tubes 6 are symmetrically installed inside the central cavity 22. A temperature sensor 8 is installed in the central cavity 22 above the two electric heating tubes 6. The bottom of the diaphragm-type feeding shell 2 is equipped with a one-way discharge structure 5 at the outlet of the two cylindrical material chambers 21; a T-shaped material pipe 4 is installed at the upper position inside the middle cavity 22. The inlet end of the T-shaped material pipe 4 is equipped with a heating unit 7 and is connected to an external isocyanate source. The two outlet ends of the T-shaped material pipe 4 are respectively connected to the corresponding cylindrical material chambers 21 on the left and right sides; a double belt drive unit 9 is set above the upper cover plate 1. The power output end of the double belt drive unit 9 is connected to the two auger pusher structures 3.

[0022] In this embodiment, the cylindrical material cavity 21 provides a smooth vertical pushing channel without complex dead angles, which facilitates the rotation and pushing of materials by the auger pushing structure 3. The gap between its cylindrical inner wall and the spiral blades is uniform, and the material is pushed horizontally along the axial direction, so that it will not be squeezed into the slit and remain there for a long time.

[0023] In this embodiment, the T-shaped feed pipe 4 has a simple structure, short flow channel, and low resistance, avoiding the dead zone caused by the use of complex three-way valves and ensuring the smooth flow of isocyanate.

[0024] A controller 10 is installed at the rear of the top of the upper cover plate 1. The controller 10 is electrically connected to the electric heating tube 6, the heating unit 7, the temperature sensor 8, and the dual belt drive unit 9.

[0025] In this embodiment, the controller 10 and the connection lines between the controller 10 and each electrical component are all existing technologies. The controller 10 receives analog signals from the temperature sensor 8 and start, stop, and speed setting signals from the operator's control panel. Then, it outputs switch and analog signals to the heating unit 7, the electric heating tube 6, and the dual belt drive unit 9 to control the corresponding heating unit 7, the electric heating tube 6, and the dual belt drive unit 9 to work.

[0026] Depend on Figure 4 and Figure 5 As shown, the heating unit 7 includes a hollow chamber 71 fixedly installed at the feed inlet of the T-shaped material tube 4. An electric heating tube 72 is installed inside the hollow chamber 71. The hollow chamber 71 is made of aluminum alloy.

[0027] The T-shaped feed tube 4 is often the place where heat loss is most severe. The feed inlet of the T-shaped feed tube 4 is designed to be short to reduce heat loss. In addition, the electric heating tube 2 72 in the hollow chamber 71 quickly raises the tube wall temperature and compensates for heat loss when the material flows.

[0028] A sealing gasket is provided between the upper cover plate 1 and the diaphragm feeding shell 2, and is fixed by bolts. The sealing gasket is used to seal the connection between the upper cover plate 1 and the diaphragm feeding shell 2, thereby improving the sealing effect.

[0029] The top cover plate 1 is equipped with a top shell 101. Under the tightening force of the bolts, the sealing gasket tightly adheres to the surfaces of the upper and lower parts, filling the microscopic unevenness and forming an airtight barrier to effectively block external moisture from entering the cavity-type feeding shell 2 for a long time. The left and right sides of the back of the cavity-type feeding shell 2 are integrally formed with perforated brackets. Bolts and fasteners can be inserted through the perforated brackets. The feeding device for preparing polyurethane materials can be easily installed as a whole through the bolts and fasteners and the perforated brackets, making it convenient to use.

[0030] The middle cavity 22 is filled with heat-conducting oil, and the electric heating tube 6 is immersed in the heat-conducting oil. The middle cavity 22 serves as an independent space for heating and temperature measurement. It does not directly contact the isocyanate but can transfer heat efficiently. After being filled with heat-conducting oil, it can transfer heat evenly.

[0031] Depend on Figure 6 , Figure 7 and Figure 8 As shown, the auger pushing structure 3 includes a solid auger spiral shaft 32 rotatably installed in the cylindrical material cavity 21. The upper end of the solid auger spiral shaft 32 passes through the upper cover plate 1 and extends to the top of the upper cover plate 1. A sealed bearing 31 is installed at the connection between the upper cover plate 1 and the solid auger spiral shaft 32. A gap is left between the blade edge of the solid auger spiral shaft 32 and the inner wall of the cylindrical material cavity 21.

[0032] With this design, the dual belt drive unit 9 is activated to drive the solid auger spiral shafts 32 on both sides to rotate synchronously. When it rotates, it generates axial thrust on the material, so the material is always moving forward, with a short residence time and a greatly reduced risk of self-agglomeration.

[0033] The one-way discharge structure 5 consists of a one-way valve 51 and a feeding pipe 52. The one-way valve 51 is coaxially arranged with the solid auger spiral shaft 32 and installed on the discharge port of the cavity-type feeding shell 2. The feeding pipe 52 is fixedly installed on the discharge end of the one-way valve 51.

[0034] When the pressure generated by the rotation of the solid auger shaft 32 is sufficient to overcome the spring force of the one-way valve 51, the one-way valve 51 opens automatically. After the auger stops, the pressure disappears and the one-way valve 51 closes immediately, completely isolating the steam in the reactor and the external moisture outside the cylindrical material chamber 21. Even if the auger pushing structure 3 stops, the isocyanate in the cylindrical material chamber 21 remains basically static but well sealed because there is no reflux channel and the outlet is closed.

[0035] The dual-belt drive unit 9 includes a double-layer frame 92 fixed at the center of the top of the upper cover plate 1. A vertically arranged main shaft 93 is rotatably mounted on the double-layer frame 92 via bearings. Two sets of synchronous belt pulley transmission structures 94 are installed at intervals along the axial direction on the main shaft 93. The other ends of the two sets of synchronous belt pulley transmission structures 94 are respectively connected to the upper end of the corresponding solid auger spiral shaft 32. A reduction motor 91 for driving the rotation of the main shaft 93 is installed on the upper cover plate 1.

[0036] With this design, the solid auger spiral shaft 32 and the main shaft 93 are connected by a synchronous belt pulley transmission structure 94. When the reduction motor 91 receives the control command from the controller 10, it drives the main shaft 93 to rotate. The main shaft 93 then drives the corresponding solid auger spiral shaft 32 to rotate through the synchronous belt pulley transmission structure 94.

[0037] In this embodiment, the synchronous belt pulley transmission structure 94 includes two synchronous pulleys, which are respectively fixedly installed on the main shaft 93 and the corresponding solid auger spiral shaft 32. A synchronous belt is sleeved on the two synchronous pulleys. At this time, the rotation of the main shaft 93 drives the corresponding solid auger spiral shaft 32 to rotate through the transmission action of the two synchronous pulleys and the synchronous belt.

[0038] In addition to this embodiment, the synchronous belt pulley drive structure 94 can also be replaced by a sprocket and chain drive structure, a gear set drive structure, or a pulley and belt drive structure.

[0039] A downward-extending recessed cavity 102 is provided at the center of the top of the upper cover plate 1. The reduction motor 91 is fixedly installed in the recessed cavity 102. The vertical height of the feeding device is reduced by the recessed cavity 102, thereby simplifying the overall volume of the device.

[0040] In this embodiment, the mounting end of the temperature sensor 8 is installed on the outside of the cavity-type feeding shell 2, the probe of the temperature sensor 8 extends into the middle cavity 22, and the probe is covered with an anti-corrosion sleeve made of stainless steel.

[0041] The present invention also provides a method of using a feeding device for preparing polyurethane materials, comprising the following steps: S1: The controller 10 issues a command to activate the heating unit 7 and the electric heating tube 6. The heating unit 7 initially heats the inlet section of the T-shaped material tube 4. The electric heating tube 6 directly heats the walls of the central cavity 22 and the cylindrical material cavities 21 on the left and right sides that are in close contact with it. The temperature sensor 8 monitors the temperature of the central cavity 22 in real time and feeds it back to the controller 10. The controller 10 has a set threshold, which is 40°C to 45°C. When the temperature sensor 8 detects that the temperature of the central cavity 22 is lower than this range, the controller 10 starts the heating unit 7 and the electric heating tube 6 to perform heating operations. After the set temperature is reached, the controller 10 switches to intermittent heating or enters the heat preservation mode, so that the metal inner wall of the cavity-type feeding shell 2 is uniformly heated to the liquid flow temperature required by isocyanate.

[0042] The working principle of heating unit 7 and electric heating tube 6 in step S1 is as follows: electric heating tube 72 in hollow chamber 71 is started under the control of controller 10 and quickly increases the tube wall temperature of T-shaped material tube 4. When the material flows, it compensates for heat loss and avoids serious heat loss of the material in T-shaped material tube 4. Electric heating tube 6 is immersed in the heat-conducting oil filled in the middle cavity 22. The middle cavity 22 serves as an independent space for heating and temperature measurement. It does not directly contact isocyanate but can transfer heat efficiently. After being filled with heat-conducting oil, it can transfer heat evenly.

[0043] S2: After preheating is completed, the isocyanate in the external storage tank is introduced into the cylindrical material chambers 21 on the left and right sides through the T-shaped material pipe 4 under the pressure of nitrogen and driven by the upstream pump. The isocyanate gradually fills the cylindrical material chambers 21 on the left and right sides. At this time, the screw conveyor pusher structure 3 is in a static state. The material in the cylindrical material chamber 21 remains in a liquid state and will not solidify because the overall temperature is maintained between 40-45℃.

[0044] S3: When a feeding operation is required, the controller 10 sends a start command to the dual belt drive unit 9, causing the auger pusher structure 3 to start rotating. Its spiral blades push the isocyanate in the cylindrical material chamber 21 toward the discharge port. The liquid isocyanate is extruded from the unidirectional discharge structure 5 and injected into the downstream reactor. The left and right material chambers work simultaneously, achieving double the output of feeding and serving as backups for each other.

[0045] In step S3, the working principle of the double belt drive unit 9 and the auger pusher structure 3 is as follows: after the reduction motor 91 receives the control command from the controller 10, it drives the main shaft 93 to rotate. The main shaft 93 drives the solid auger spiral shaft 32 on the corresponding side to rotate through the synchronous belt pulley transmission structure 94. The solid auger spiral shaft 32 rotates in the cylindrical material cavity 21 and generates axial thrust on the material, pushing the material in the cylindrical material cavity 21 to be discharged from the one-way discharge structure 5.

[0046] In step S3, the working principle of the one-way discharge structure 5 is as follows: when the pressure generated by the rotation of the solid auger spiral shaft 32 is sufficient to overcome the spring force of the one-way valve 51, the one-way valve 51 automatically opens. At this time, the material in the cylindrical material chamber 21 is injected into the downstream reactor through the one-way valve 51 and the feeding pipe 52.

[0047] S4: When the feeding ends, the system enters the stop and standby stage. The controller 10 receives the stop signal and cuts off the power of the double belt drive unit 9, causing the screw conveyor pusher structure 3 to stop rotating. At this time, the material in the cylindrical material chambers 21 on the left and right sides no longer moves forward, and due to the cut-off effect of the one-way discharge structure 5, the gas and moisture in the reactor cannot flow back into the cylindrical material chamber 21.

[0048] In step S4, the working principle of the one-way discharge structure 5 is as follows: when the solid auger spiral shaft 32 of the auger pusher structure 3 stops rotating, the pressure disappears, and the one-way valve 51 immediately closes, completely isolating the steam in the reactor and the external moisture outside the cylindrical material chamber 21.

[0049] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A feeding device for preparing polyurethane materials, characterized in that: The upper cover plate (1) is fixedly installed on the bottom surface of the upper cover plate (1). The cavity feeding shell (2) is provided with a middle cavity (22) and cylindrical material cavities (21) located on the left and right sides of the middle cavity (22). The cylindrical material cavities (21) are equipped with an auger pusher structure (3) for pushing isocyanate to the outlet. Two electric heating tubes (6) are symmetrically installed inside the middle cavity (22). A temperature sensor (8) is installed in the middle cavity (22) above the two electric heating tubes (6). The cavity feeding shell (2) is fixedly installed on the bottom surface of the upper cover plate (1). The bottom end is equipped with a one-way discharge structure (5) at the outlet of the two cylindrical material cavities (21); a T-shaped material pipe (4) is installed at the upper position inside the middle cavity (22). A heating unit (7) is installed at the inlet end of the T-shaped material pipe (4) and is connected to the external isocyanate source. The two outlet ends of the T-shaped material pipe (4) are connected to the corresponding cylindrical material cavities (21) on the left and right sides respectively; a double belt drive unit (9) is set above the upper cover plate (1). The power output end of the double belt drive unit (9) is connected to the two auger pusher structures (3) for transmission.

2. The feeding device for preparing polyurethane materials according to claim 1, characterized in that: The heating unit (7) includes a hollow chamber (71) fixedly installed at the feed inlet of the T-shaped material tube (4). An electric heating tube (72) is installed inside the hollow chamber (71). The hollow chamber (71) is made of aluminum alloy.

3. The feeding device for preparing polyurethane materials according to claim 2, characterized in that: A sealing gasket is provided between the upper cover plate (1) and the cavity-type feeding shell (2), and a top shell (101) is installed on the top of the upper cover plate (1).

4. The feeding device for preparing polyurethane materials according to claim 3, characterized in that: The auger pushing structure (3) includes a solid auger spiral shaft (32) rotatably installed in the cylindrical material cavity (21). The upper end of the solid auger spiral shaft (32) passes through the upper cover plate (1) and extends to the top of the upper cover plate (1). A sealed bearing (31) is installed at the connection between the upper cover plate (1) and the solid auger spiral shaft (32). A gap is left between the blade edge of the solid auger spiral shaft (32) and the inner wall of the cylindrical material cavity (21).

5. The feeding device for preparing polyurethane materials according to claim 4, characterized in that: The one-way discharge structure (5) consists of a one-way valve (51) and a feeding pipe (52). The one-way valve (51) is coaxially arranged with the solid auger spiral shaft (32) and installed on the discharge port of the cavity-type feeding shell (2). The feeding pipe (52) is fixedly installed on the discharge end of the one-way valve (51).

6. The feeding device for preparing polyurethane materials according to claim 5, characterized in that: The back of the cavity-type feeding shell (2) is integrally formed with perforated brackets on both the left and right sides. The middle cavity (22) is filled with heat-conducting oil, and the electric heating tube (6) is immersed in the heat-conducting oil.

7. The feeding device for preparing polyurethane materials according to claim 6, characterized in that: The dual-belt drive unit (9) includes a double-layer frame (92) fixed at the center of the top of the upper cover plate (1). A vertically arranged main shaft (93) is rotatably mounted on the double-layer frame (92). Two sets of synchronous belt pulley transmission structures (94) are installed at intervals along the axial direction on the main shaft (93). The other ends of the two sets of synchronous belt pulley transmission structures (94) are respectively connected to the upper end of the corresponding solid auger spiral shaft (32). A reduction motor (91) for driving the rotation of the main shaft (93) is installed on the upper cover plate (1).

8. The feeding device for preparing polyurethane materials according to claim 7, characterized in that: A downward-extending recessed cavity (102) is provided at the center of the top of the upper cover plate (1), and a reduction motor (91) is fixedly installed in the recessed cavity (102).

9. A feeding device for preparing polyurethane materials according to claim 8, characterized in that: A controller (10) is installed at the rear of the top of the upper cover plate (1). The controller (10) is electrically connected to the electric heating tube (6), the heating unit (7), the temperature sensor (8), and the double belt drive unit (9).

10. A method of using a feeding device for preparing polyurethane materials, comprising using the feeding device for preparing polyurethane materials as described in any one of claims 1-9, characterized in that: Includes the following steps: S1: The controller (10) issues a command to turn on the heating unit (7) and the electric heating tube (6). The heating unit (7) initially heats the feed inlet section of the T-shaped material tube (4). The electric heating tube (6) directly heats the middle cavity (22) and the cylindrical material cavities (21) on the left and right sides that are closely attached to it. The temperature sensor (8) monitors the temperature of the middle cavity (22) in real time and feeds it back to the controller (10). The controller (10) has a set threshold inside. The set threshold is 40°C to 45°C. When the temperature sensor (8) detects that the temperature of the middle cavity (22) is lower than this range, the controller (10) starts the heating unit (7) and the electric heating tube (6) to perform heating operation. After the set temperature is reached, the controller (10) switches to intermittent heating or enters the heat preservation mode, so that the metal inner wall of the cavity feeding shell (2) is uniformly heated to the liquid flow temperature required by the isocyanate. S2: After preheating, the isocyanate in the external storage tank is introduced into the cylindrical material chambers (21) on the left and right sides through the T-shaped material pipe (4) under the pressure of nitrogen and the drive of the upstream pump. The isocyanate gradually fills the cylindrical material chambers (21) on the left and right sides. At this time, the screw conveyor pusher structure (3) is in a static state. The material in the cylindrical material chamber (21) remains liquid and will not solidify because the overall temperature is maintained between 40-45℃. S3: When feeding is required, the controller (10) sends a start command to the dual belt drive unit (9) to make the screw conveyor pusher structure (3) start to rotate. Its spiral blades push the isocyanate in the cylindrical material chamber (21) to move towards the discharge port. The liquid isocyanate is extruded through the one-way discharge structure (5) and injected into the downstream reactor. The left and right material chambers work at the same time, and the feeding amount is doubled and can be used as backups for each other. S4: When the feeding ends, the system enters the stop and standby stage. The controller (10) receives the stop signal and cuts off the power of the double belt drive unit (9), causing the screw conveyor pusher structure (3) to stop rotating. At this time, the material in the cylindrical material chambers (21) on the left and right sides no longer moves forward. And due to the cut-off effect of the one-way discharge structure (5), the gas and moisture in the reactor cannot flow back into the cylindrical material chamber (21).

Images