CN221022223U - Super critical fluid auxiliary polymer extrusion foaming device based on melt self-sealing - Google Patents

Abstract

The supercritical fluid assisted polymer extrusion foaming device based on melt self-sealing comprises a charging barrel, an extrusion screw and an extrusion screw driving device; the extrusion screw comprises a key connecting section, a thread sealing section, a compression section, a separation section and a conveying section; the compression section and the conveying section are provided with spiral screw edges with opposite rotation directions, the compression section screw edges and the inner wall of the charging barrel enclose a high-pressure melt cavity, the bottom diameter of the compression section screw edges is gradually increased from front to back, and the conveying section screw edges and the inner wall of the charging barrel enclose a melt extrusion cavity; the charging barrel is provided with a first feeding port and a discharging port which are communicated with the high-pressure melt cavity, and a second feeding port and a third feeding port which are communicated with the melt extrusion cavity; and a bypass valve capable of adjusting the pressure of the homogeneous solution in the high-pressure melt cavity is also connected between the discharge port and the third feed port. The utility model effectively solves the problems that supercritical fluid is easy to separate out from polymer melt and gas is easy to leak from a clearance at the tail end of an extrusion screw in the extrusion process, and belongs to polymer extrusion foaming devices.

Description

Super critical fluid auxiliary polymer extrusion foaming device based on melt self-sealing

Technical Field

The utility model relates to a polymer extrusion foaming device, in particular to a cooling extruder at a second stage in a double-stage extruder.

Background

Supercritical fluid extrusion foaming is an advanced polymer material processing technique. In the extrusion process, fluid in a supercritical state (usually non-reactive gas such as carbon dioxide or nitrogen) is injected into a cylinder of an extruder, and the supercritical fluid rapidly diffuses and dissolves in a polymer melt under the action of screw shearing and mixing to form a polymer/supercritical fluid homogeneous solution; then, the homogeneous solution is extruded through an extruder die, dissolved supercritical fluid is rapidly separated out due to the huge pressure drop at the moment of extrusion, a large number of bubble nuclei are induced in the extruded melt, and in the subsequent cooling process, the bubble nuclei in the extruded melt are continuously grown and shaped, so that the microporous foamed plastic extruded product is finally obtained. The microporous plastic product produced based on the supercritical fluid extrusion foaming technology has the advantages of light weight, high specific strength, good impact load absorption capacity, heat insulation, sound insulation, buffering, insulation, corrosion resistance and the like, and is widely applied to industries such as buildings, automobiles, medicines, shoe materials, electronics, food packaging and the like.

At present, the types of equipment for extruding and forming microporous foamed plastic products (including plates, sheets, profiles, films and the like) by using supercritical fluid are single-screw, double-stage extruders and the like. The double-stage extruder is formed by connecting two independent extrusion units (namely a foaming extruder and a cooling extruder) in series, and the foaming extruder is mainly responsible for melting plasticization of plastic particles and injection and mixing of supercritical fluid so as to form a polymer/supercritical fluid homogeneous solution; the cooling extruder is mainly responsible for precisely regulating and controlling the temperature of the homogeneous solution so as to stably and high-quality extrude and form the required foaming parts and the like. Because the double-stage extruder has the comprehensive advantages of high production efficiency, stable product quality, low energy consumption and the like, the double-stage extruder is the most widely used forming equipment in the extrusion foaming industry.

When a double-stage extruder is used for carrying out supercritical fluid extrusion foaming production, one of the key technologies to be solved is to prevent the problem that when a polymer/supercritical fluid homogeneous solution is conveyed from a foaming extruder to a cooling extruder, the supercritical fluid dissolved in a polymer melt is separated out from the melt due to local pressure drop, and the separated gas leaks from a mechanical assembly gap at the tail part of the cooling extruder. The leakage of gas results in a substantial reduction in the concentration of supercritical fluid dissolved in the polymer melt, thereby affecting the foaming effect and reducing the quality of the extruded foam article. The prior art solution is to install graphite packing at the tail of the cooling extruder barrel to seal the assembly gap of the screw and barrel to prevent leakage of gas. However, in the use process, the screw rod rotates at a high speed in the machine barrel to drive the graphite packing to deform and wear, so that the tail end of the cooling extruder is required to be disassembled and assembled regularly to maintain or replace the graphite packing, the sealing effect is ensured, the maintenance cost is increased, the continuous operation of equipment is influenced, and the production efficiency of extrusion foaming is greatly reduced.

Disclosure of utility model

Aiming at the technical problems existing in the prior art, the utility model aims at: the supercritical fluid assisted polymer extrusion foaming device based on melt self-sealing is provided to solve the problems that in the prior art, supercritical fluid is easy to separate out from polymer melt and separated gas is easy to leak from a gap at the tail end of a cooling extruder.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

The supercritical fluid assisted polymer extrusion foaming device based on melt self-sealing comprises a charging barrel, an extrusion screw rod arranged in the charging barrel, and an extrusion screw rod driving device connected with the rear end of the extrusion screw rod; the extrusion screw comprises a key connection section, a thread sealing section, a compression section, a separation section and a conveying section which are sequentially arranged from back to front; the separation section is cylindrical and is in clearance fit with the inner hole of the charging barrel; the compression section and the conveying section are provided with spiral screw edges with opposite rotation directions, the screw edges of the compression section and the inner wall of the charging barrel enclose a high-pressure melt cavity, the bottom diameter of the screw edges of the compression section is gradually increased from front to back along the extrusion direction of homogeneous solution in the high-pressure melt cavity, and the screw edges of the conveying section and the inner wall of the charging barrel enclose a melt extrusion cavity; the charging barrel is provided with a first feeding port and a discharging port which are communicated with the high-pressure melt cavity; the charging barrel is also provided with a second charging port and a third charging port which are communicated with the melt extrusion cavity; and a bypass valve capable of adjusting the pressure of the homogeneous solution in the high-pressure melt cavity is also connected between the discharge port and the third feed port.

Preferably, the size of the gap between the separation section and the inner hole of the charging barrel is 0.02-0.1mm.

Preferably, the bypass valve comprises a valve body, a conical valve core, a spring, a set screw, an end cap and a pressure sensor; the valve body is internally drilled with a feeding hole, a discharging hole and a stepped hole, and the feeding hole and the discharging hole are respectively communicated with small-diameter holes of the stepped hole; the conical valve core comprises a flange end and a conical end, the flange end is arranged in a large-diameter hole of the stepped hole, the conical end is arranged in a small-diameter hole of the stepped hole in a clearance fit manner, and when the conical valve core axially slides along the stepped hole, the conical end communicates or blocks a discharging hole with the small-diameter hole of the stepped hole; after the adjusting screw is connected with the threaded through hole of the end cover, the bottom end of the adjusting screw is inserted into the large-diameter hole of the stepped hole; the spring is arranged in the large-diameter hole of the stepped hole and is compressed between the bottom end face of the adjusting screw and the top end face of the flange end of the conical valve core; the end cover is fixed at one end of the valve body through a screw; the pressure sensor is arranged in the valve body, and the measuring end of the pressure sensor is communicated with the small-diameter hole of the stepped hole in the valve body.

Preferably, the feed hole of the bypass valve is communicated with the discharge hole on the feed cylinder through a feed pipe; and the discharge hole of the bypass valve is communicated with a third feed inlet on the feed cylinder through a discharge pipe.

Preferably, a sealing ring for preventing the homogeneous solution from flowing out to the large-diameter hole of the stepped hole is further arranged between the conical end of the conical valve core and the inner wall of the small-diameter hole of the stepped hole.

Preferably, the supercritical fluid assisted polymer extrusion foaming device based on melt self-sealing further comprises a connector, and a die of the foaming extruder is connected with the charging barrel through the connector; the connector is provided with an inlet and two outlets, a fluid channel is arranged in the connector, the two outlets are connected in parallel through the fluid channel to be connected into the inlet, the inlet is communicated with a mouth die of the foaming extruder, and the two outlets are respectively communicated with a first feeding port and a second feeding port of the charging barrel.

Preferably, the extrusion screw driving device comprises an extrusion motor and a speed reducer; the extrusion motor is connected with the input end of the speed reducer, and the output shaft of the speed reducer is connected with the key connecting section of the extrusion screw; the rear end of the charging barrel is connected with a flange at the output end of the speed reducer.

Preferably, the outer wall surface of the barrel is provided with a heating device; the outer surface of the valve body is also provided with a heating device. The heating device can be an electric heating ring, an electromagnetic induction coil or an infrared heating cylinder, etc.

Preferably, the axial direction of the extrusion screw and the barrel is arranged along the horizontal direction, the first feed inlet and the second feed inlet are positioned at the upper end of the barrel, and the discharge outlet and the third feed inlet are positioned at the lower end of the barrel.

Preferably, the heating means is an electric heating coil, an electromagnetic induction coil or an infrared heating cylinder.

The working principle of the utility model is as follows: the polymer/supercritical fluid homogeneous solution formed in the foaming extruder is shunted by the connector and then enters the high-pressure melt cavity and the melt extrusion cavity through the first feed inlet and the second feed inlet of the charging barrel, and the compression section and the conveying section of the extrusion screw are provided with screw edges with opposite rotation directions, so that under the rotation driving action of the extrusion screw, the homogeneous solution entering the melt extrusion cavity is continuously conveyed along the front end direction of the extrusion screw, and the homogeneous solution entering the high-pressure melt cavity is continuously conveyed along the tail section of the extrusion screw. Because the bottom diameter of the screw rib of the compression section of the extrusion screw is gradually increased along the extrusion direction of the melt in the high-pressure melt cavity, the homogeneous solution entering the high-pressure melt cavity is continuously compressed while continuously transported, so that a high-pressure area of the homogeneous solution is formed in the high-pressure melt cavity. The pressure of the homogeneous solution in the high-pressure melt cavity can be flexibly regulated and controlled by regulating the precompression amount of the spring in the bypass valve, and when the pressure of the homogeneous solution in the high-pressure area exceeds the saturation pressure of the supercritical fluid, the formed high-pressure area not only ensures that the supercritical fluid dissolved in the polymer melt is not easy to separate out, but also can prevent the separated gas from leaking from a mechanical gap at the tail part of the extrusion screw, thereby playing a self-sealing role. The high-pressure homogeneous solution in the high-pressure melt cavity enters the melt extrusion cavity from the third feed inlet of the feed cylinder after passing through the bypass valve, is mixed with the homogeneous solution, and is continuously extruded and molded, so that the required microporous foaming product is finally obtained.

The utility model has the following advantages:

(1) The supercritical fluid assisted polymer extrusion foaming device provided by the utility model can form a melt high-pressure area at the tail end of the extrusion screw rod to generate a self-sealing effect, and can effectively solve the problems that the supercritical fluid is easy to separate out from the polymer melt and gas leaks from a gap at the tail end of the extrusion screw rod.

(2) Compared with the prior art, the supercritical fluid assisted polymer extrusion foaming device based on melt self-sealing does not need to be disassembled and maintained regularly, so that continuous operation of extrusion foaming production is effectively ensured, and efficient and high-quality production of microporous plastic parts is realized.

(3) The utility model has the advantages of simple structure and stable production process, and is easy to popularize and apply in the extrusion foaming industrial production.

(4) The connector is designed, so that the utility model can be well integrated with the foaming extruder in structure. The fluid channel structure of the connector is designed to enable the polymer/supercritical fluid homogeneous phase solution conveyed from the foaming extruder to flow into the high-pressure melt cavity and the melt extrusion cavity in proportion in a split manner.

Drawings

FIG. 1 is a schematic structural diagram of a supercritical fluid-assisted polymer extrusion foaming device based on melt self-sealing according to the present utility model.

Fig. 2 is a partial enlarged view at a in fig. 1.

Fig. 3 is a schematic view of the structure of an extrusion screw.

Fig. 4 is a schematic structural view of the cartridge.

Fig. 5 is an exploded schematic view of the bypass valve.

The reference numerals in the above figures are as follows: 1-a charging barrel; 1-1 to a first feed inlet; 1-2 parts of a discharge hole; 1-3-a second feed inlet; 1-4 to a third feed inlet; 2-extruding a screw; 2-1-a bond linkage segment; 2-a thread seal section; 2-3-compression section; 2-4-separating section; 2-5-conveying sections; 3-high pressure melt chamber; 4-a melt extrusion chamber; 5-a bypass valve; 5-1, a valve body; 5-2-a conical valve core; 5-3-springs; 5-4-adjusting screws; 5-end cap; 5-6, a pressure sensor; 5-7-feeding holes; 5-8, namely a discharge hole; 5-9-step holes; 5-10 parts of a sealing ring; 6, a feeding pipe; 7, a discharging pipe; 8-an extrusion motor; 9-a speed reducer; 10-a linker; 11-a foaming extruder; 12-an electric heating ring.

Detailed Description

The present utility model will be described in further detail with reference to examples and drawings, but embodiments of the present utility model are not limited thereto.

Fig. 1 to 5 show a specific structure of a supercritical fluid-assisted polymer extrusion foaming device based on melt self-sealing according to the present utility model, which comprises a barrel 1, an extrusion screw 2 arranged in the barrel, and an extrusion screw driving device connected with the rear end of the extrusion screw. The extrusion screw 2 is provided with a key connecting section 2-1, a thread sealing section 2-2, a compression section 2-3, a separation section 2-4 and a conveying section 2-5 in sequence. Wherein, the separation section 2-4 is cylindrical and is in clearance fit with the inner hole of the charging barrel 1, and the size of the clearance is 0.02-0.1mm. The compression section 2-3 and the conveying section 2-5 of the extrusion screw 2 are provided with spiral screw edges with opposite rotation directions (if the compression section 2-3 screw edges are left-handed and the conveying section 2-5 screw edges are right-handed), the compression section 2-3 screw edges and the inner wall surface of the charging barrel 1 enclose a high-pressure melt cavity 3, the bottom diameter of the compression section 2-3 screw edges is gradually increased along the extrusion direction of melt in the high-pressure melt cavity 3, and the conveying section 2-5 screw edges and the inner wall surface of the charging barrel 1 enclose a melt extrusion cavity 4. The feed cylinder 1 is provided with a first feed inlet 1-1 and a discharge outlet 1-2 which are communicated with the high-pressure melt cavity 3, the feed cylinder 1 is also provided with a second feed inlet 1-3 and a third feed inlet 1-4 which are communicated with the melt extrusion cavity 4, and a bypass valve 5 which can adjust the pressure of the homogeneous solution in the high-pressure melt cavity is also connected between the discharge outlet 1-2 and the third feed inlet 1-4.

As shown in fig. 2 and 5, the bypass valve 5 includes a valve body 5-1, a tapered valve spool 5-2, a spring 5-3, a set screw 5-4, an end cap 5-5, and a pressure sensor 5-6. The valve body 5-1 is internally provided with a feeding hole 5-7, a discharging hole 5-8 and a stepped hole 5-9, and the feeding hole 5-7 and the discharging hole 5-8 are respectively communicated with two ends of a small-diameter hole of the stepped hole 5-9. The conical valve core 5-2 comprises a flange end and a conical end, wherein the flange end is arranged in a large-diameter hole of the stepped hole, the conical end is arranged in a small-diameter hole of the stepped hole 5-9 in a clearance fit manner, and the length of the conical end is suitable for enabling the small-diameter hole of the stepped hole 5-9 to be communicated with the discharge hole 5-8 or blocking when the conical valve core 5-2 is controlled to slide back and forth in the stepped hole 5-9. The bottom end of the adjusting screw 5-4 is inserted into the large-diameter hole of the stepped hole 5-9 after being connected with the threaded through hole of the end cover 5-5. The spring 5-3 is arranged in the large diameter hole of the stepped hole 5-9, and two ends of the spring are respectively tightly attached to the bottom end face of the adjusting screw 5-4 and the top end face of the flange of the conical valve core 5-2. The end cap 5-5 is fixed to one end of the valve body 5-1 by a screw. The pressure sensor 5-6 is arranged in the valve body 5-1, and the measuring end of the pressure sensor is communicated with the small diameter hole of the stepped hole 5-9 in the valve body 5-1. In addition, a sealing ring 5-10 is arranged between the conical end of the conical valve core 5-2 and the inner wall of the small-diameter hole of the stepped hole 5-9 so as to prevent homogeneous solution in the small-diameter hole from flowing out to the large-diameter hole. The stepped hole is a second-order hole, and comprises a large-diameter hole and a small-diameter hole, wherein the feeding hole and the discharging hole are communicated with the small-diameter hole and are perpendicular to the small-diameter hole, the discharging hole is arranged at one end close to the large-diameter hole, and the feeding hole is arranged at one end far away from the large-diameter hole.

The feed hole 5-7 of the bypass valve 5 is communicated with the discharge hole 1-2 on the feed cylinder 1 through the feed pipe 6, and the discharge hole 5-8 of the bypass valve 5 is communicated with the third feed hole 1-4 on the feed cylinder 1 through the discharge pipe 7.

As shown in fig. 1, the extrusion screw driving device comprises an extrusion motor 8 and a speed reducer 9, the extrusion motor 8 is connected with the input end of the speed reducer 9, the output shaft of the speed reducer 9 is connected with the key connecting section 2-1 of the extrusion screw 2, and the tail end of the charging barrel 1 is connected with the flange of the output end of the speed reducer 9.

As shown in fig. 1, the first feed port 1-1 and the second feed port 1-3 of the cylinder are respectively communicated with the die of the foaming extruder 11 through a connecting body 10. The connector is provided with an inlet and two outlets, a fluid channel is arranged in the connector, the two outlets are connected in parallel through the fluid channel to be connected into the inlet, the inlet is communicated with a mouth die of the foaming extruder, and the two outlets are respectively communicated with a first feeding port and a second feeding port of the charging barrel.

Further, an electric heating coil 12 is provided on the outer wall surface of the cartridge 1, and an electric heating coil 12 is also provided on the outer surface of the valve body of the bypass valve 5.

The axial direction of extrusion screw and feed cylinder sets up along the horizontal direction, and first feed inlet and second feed inlet are located the upper end of feed cylinder, and discharge gate and third feed inlet are located the lower extreme of feed cylinder. The connector is located the upper end, and the bypass valve sets up in the lower extreme.

The working process of the melt self-sealing-based supercritical fluid assisted polymer extrusion foaming device is as follows: firstly, an electric heating ring 12 arranged on the outer wall surface of the charging barrel 1 and the surface of the bypass valve 5 heats the charging barrel 1 and the valve body 5-1 to be higher than the melting temperature of a polymer (such as 180 ℃), an extrusion motor 8 is started after the temperature is stable, and the output torque of the extrusion motor 8 is amplified by a speed reducer 9 and drives the extrusion screw 2 to rotate. Then, the polymer/supercritical carbon dioxide homogeneous solution formed in the foaming extruder 11 is split by the connector 10 and then enters the high-pressure melt cavity 3 and the melt extrusion cavity 4 through the first feed port 1-1 and the second feed port 1-3 of the feed cylinder, and the compression section 2-3 and the conveying section 2-5 of the extrusion screw 2 are provided with screw edges with opposite rotation directions, so that the homogeneous solution entering the melt extrusion cavity 4 is continuously conveyed along the front end direction of the extrusion screw 2 under the action of the rotation driving of the extrusion screw 2, and the homogeneous solution entering the high-pressure melt cavity 3 is continuously conveyed along the tail end direction of the extrusion screw. Because the bottom diameter of the screw edges of the compression sections 2-3 of the extrusion screw 2 is gradually increased along the extrusion direction of the melt in the high-pressure melt cavity 3, the homogeneous solution entering the high-pressure melt cavity 3 is continuously compressed while being continuously transported, so that a high-pressure area of the homogeneous solution is formed in the high-pressure melt cavity 3. Subsequently, the high-pressure homogeneous solution in the high-pressure melt chamber 3 enters into the small diameter hole of the stepped hole 5-9 of the valve body 5-1 through the discharge port 1-2 of the cylinder, the feed pipe 6 and the feed hole 5-7 of the bypass valve 5. At this time, the adjusting screw 5-4 is rotated to make the spring 5-3 generate a certain precompression amount, and at the same time, the pressure value of the pressure sensor 5-6 is observed, and when the pressure of the homogeneous solution is gradually increased to a preset value (such as 15MPa, which is usually higher than the saturation pressure of the supercritical carbon dioxide), the rotation of the adjusting screw 5-4 is stopped, so that the pressure of the homogeneous solution in the high-pressure melt chamber 3 can be stabilized at a preset pressure level. Since the pressure of the homogeneous solution in the high-pressure melt chamber 3 exceeds the saturation pressure of supercritical carbon dioxide (e.g., 7.38 MPa), not only is dissolved supercritical carbon dioxide less likely to precipitate from the polymer melt, but also carbon dioxide gas that has precipitated from the polymer melt is not allowed to leak through the high-pressure region from the mechanical gap at the end of the extrusion screw 2. Finally, the high-pressure homogeneous solution in the small-diameter holes of the stepped holes 5-9 enters the melt extrusion cavity 4 through the discharge holes 5-8 of the bypass valve 5, the discharge pipe 7 and the third feed inlet 1-4 of the feed cylinder 1, is mixed with the homogeneous solution, and is continuously extruded and molded, and finally the required microporous foaming product is obtained.

The above examples are preferred embodiments of the present utility model, but the embodiments of the present utility model are not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principle of the present utility model should be made in the equivalent manner, and the embodiments are included in the protection scope of the present utility model.

Claims (9)

1. The utility model provides a super critical fluid auxiliary polymer extrusion foaming device based on fuse-element self sealss, includes the feed cylinder, sets up the extrusion screw rod in the feed cylinder, with the extrusion screw rod drive arrangement who extrudes the screw rod rear end and meet, its characterized in that: the extrusion screw comprises a key connection section, a thread sealing section, a compression section, a separation section and a conveying section which are sequentially arranged from back to front; the separation section is cylindrical and is in clearance fit with the inner hole of the charging barrel; the compression section and the conveying section are provided with spiral screw edges with opposite rotation directions, the screw edges of the compression section and the inner wall of the charging barrel enclose a high-pressure melt cavity, the bottom diameter of the screw edges of the compression section is gradually increased from front to back along the extrusion direction of homogeneous solution in the high-pressure melt cavity, and the screw edges of the conveying section and the inner wall of the charging barrel enclose a melt extrusion cavity; the charging barrel is provided with a first feeding port and a discharging port which are communicated with the high-pressure melt cavity; the charging barrel is also provided with a second charging port and a third charging port which are communicated with the melt extrusion cavity; and a bypass valve capable of adjusting the pressure of the homogeneous solution in the high-pressure melt cavity is also connected between the discharge port and the third feed port.

2. The melt self-sealing based supercritical fluid-assisted polymer extrusion foaming apparatus according to claim 1, wherein: the size of the gap between the separation section and the inner hole of the charging barrel is 0.02-0.1mm.

3. The melt self-sealing based supercritical fluid-assisted polymer extrusion foaming apparatus according to claim 1, wherein: the bypass valve comprises a valve body, a conical valve core, a spring, an adjusting screw, an end cover and a pressure sensor; the valve body is internally drilled with a feeding hole, a discharging hole and a stepped hole, and the feeding hole and the discharging hole are respectively communicated with small-diameter holes of the stepped hole; the conical valve core comprises a flange end and a conical end, the flange end is arranged in a large-diameter hole of the stepped hole, the conical end is arranged in a small-diameter hole of the stepped hole in a clearance fit manner, and when the conical valve core axially slides along the stepped hole, the conical end communicates or blocks a discharging hole with the small-diameter hole of the stepped hole; after the adjusting screw is connected with the threaded through hole of the end cover, the bottom end of the adjusting screw is inserted into the large-diameter hole of the stepped hole; the spring is arranged in the large-diameter hole of the stepped hole and is compressed between the bottom end face of the adjusting screw and the top end face of the flange end of the conical valve core; the end cover is fixed at one end of the valve body through a screw; the pressure sensor is arranged in the valve body, and the measuring end of the pressure sensor is communicated with the small-diameter hole of the stepped hole in the valve body.

4. A melt self-sealing based supercritical fluid assisted polymer extrusion foaming device according to claim 3, wherein: the feed hole of the bypass valve is communicated with the discharge hole on the feed cylinder through a feed pipe; and the discharge hole of the bypass valve is communicated with a third feed inlet on the feed cylinder through a discharge pipe.

5. A melt self-sealing based supercritical fluid assisted polymer extrusion foaming device according to claim 3, wherein: a sealing ring for preventing homogeneous solution from flowing out to a large-diameter hole of the stepped hole is further arranged between the conical end of the conical valve core and the inner wall of the small-diameter hole of the stepped hole.

6. The melt self-sealing based supercritical fluid-assisted polymer extrusion foaming apparatus according to claim 1, wherein: the foaming extruder also comprises a connecting body, and the die of the foaming extruder is connected with the charging barrel through the connecting body; the connector is provided with an inlet and two outlets, a fluid channel is arranged in the connector, the two outlets are connected in parallel through the fluid channel to be connected into the inlet, the inlet is communicated with a mouth die of the foaming extruder, and the two outlets are respectively communicated with a first feeding port and a second feeding port of the charging barrel.

7. The melt self-sealing based supercritical fluid-assisted polymer extrusion foaming apparatus according to claim 1, wherein: the extrusion screw driving device comprises an extrusion motor and a speed reducer; the extrusion motor is connected with the input end of the speed reducer, and the output shaft of the speed reducer is connected with the key connecting section of the extrusion screw; the rear end of the charging barrel is connected with a flange at the output end of the speed reducer.

8. A melt self-sealing based supercritical fluid assisted polymer extrusion foaming device according to claim 3, wherein: the outer wall surface of the charging barrel is provided with a heating device; the outer surface of the valve body is also provided with a heating device.

9. The melt self-sealing based supercritical fluid-assisted polymer extrusion foaming apparatus according to claim 1, wherein: the axial direction of extrusion screw and feed cylinder sets up along the horizontal direction, and first feed inlet and second feed inlet are located the upper end of feed cylinder, and discharge gate and third feed inlet are located the lower extreme of feed cylinder.