Extruder exhaust screw and pin cold feeding exhaust extruder

Abstract

The utility model provides an exhaust screw of an extruder, which is applied to a pin cold feeding exhaust extruder with a single screw and comprises a screw mounted in a cylinder of the extruder. The screw rod is provided with a screw rod exhaust section capable of accelerating exhaust of gas in the rubber material in a region corresponding to the exhaust section of the machine barrel, and a plurality of damping grooves which are consistent with the screw rod in the length direction and can perform strip pressing and shearing on the rubber material are formed in the screw edge end face of the screw rod exhaust section; and the screw exhaust section is configured to cut off the rubber material penetrating through the damping groove under the rotation action of the screw by virtue of the damping groove so as to exhaust gas in the rubber material. When the device is used, rubber materials can be pressed into the multiple damping grooves in the conveying process, the rubber materials are divided, the strip pressing effect on the rubber materials is achieved, the threaded rod exhaust section rapidly cuts off the thin-strip-shaped rubber materials penetrating through the damping grooves by means of the effect that the damping grooves continuously rotate on the threaded rod, residual gas in the rubber materials is exhausted, and therefore the rubber materials are prevented from falling off. Therefore, the exhaust of the exhaust section of the screw rod to the gas in the rubber material can be enhanced.

Description

Technical Field

[0001] The present application relates to the technical field of rubber extruders, and in particular to an extruder exhaust screw and a pin cold feed exhaust extruder. Background Art

[0002] Rubber extruder is one of the key equipment for rubber production in industry. In the traditional production process of rubber products, there are different types of production equipment such as plunger extruder, screw type hot feed extruder, ordinary cold feed extruder, main and auxiliary thread cold feed extruder, cold feed exhaust extruder, pin cold feed extruder, composite extruder, etc.

[0003] Pin cold feed extruder is a commonly used equipment in rubber processing. At present, preforms of molded products are mostly extruded by pin cold feed extruder. Its core component is the extrusion screw. The rubber is stirred, mixed, heated, plasticized, etc. through the joint action of the extrusion screw and the barrel, and finally extruded through the die head at a certain extrusion temperature. This extruder has greatly improved the plasticization performance of the rubber, the density of the extruded products, and the extrusion volume due to the addition of pins on the barrel. However, the large amount of air involved in the feeding process and the volatile gas contained in the rubber cannot be discharged during the extrusion process and enter the preform, which will cause a large number of pores in the molded product. Pores are one of the biggest defects of rubber products and will cause aging and damage of rubber parts.

[0004] The main feature of the pin cold feed venting extruder is that the venting port is opened on the barrel to vent in the venting section. Although the mixed gas in the barrel during the extrusion process can be extracted through the venting port, its venting effect is limited. The process cannot release the gas in the rubber compound well, and the use of its screw has little effect on the release of gas in the rubber compound.

[0005] In view of the fact that the current pin cold feed extruder and pin cold feed venting extruder are both unable to effectively discharge the large amount of air drawn in during the feeding process and the volatile gases contained in the rubber compound during use, the present application proposes an extruder venting screw and a pin cold feed venting extruder. Utility Model Content

[0006] In order to solve the problems existing in the above-mentioned background technology, the present application provides an extruder exhaust screw and a pin cold feed exhaust extruder, which can better release the gas in the rubber compound by using an improved screw, thereby removing the pores in the rubber product.

[0007] In order to solve the above technical problems, this application adopts the following technical solutions:

[0008] On one hand, the present application provides an extruder exhaust screw, which is applied to a single-screw pin cold feed exhaust extruder, and the extruder exhaust screw includes a screw installed in a barrel of the extruder;

[0009] The screw is provided with a screw exhaust section capable of accelerating the discharge of gas in the rubber material in the area corresponding to the exhaust section of the barrel, and a plurality of damping grooves which are consistent with the length direction of the screw and can press and shear the rubber material are opened on the end face of the screw ridge of the screw exhaust section. The screw exhaust section is configured to cut off the rubber material passing through the damping groove under the rotation of the screw by means of the damping groove to discharge the gas in the rubber material.

[0010] In an optional manner of the present application, the damping grooves are arranged in a spiral shape and are evenly opened on the spiral edge end face of the screw exhaust section, and the damping grooves are evenly distributed on the spiral edge end face corresponding to a pitch length range of the screw exhaust section.

[0011] In an optional manner of the present application, the damping groove is an arc-shaped groove with a semicircular cross-section.

[0012] In an optional manner of the present application, the interval width between adjacent damping grooves is 0.8-1.2 times the normal width of the screw fin, and the width of the damping groove is 0.2-0.5 times the normal width of the screw fin.

[0013] In an optional embodiment of the present application, a first flow limiting plate is provided in the screw groove corresponding to the damping groove opened on the end face of the screw ridge of the screw exhaust section, which is consistent with the direction of the damping groove and can limit the spiral conveying of the rubber in the screw groove. The first flow limiting plate is connected to the screw groove between the damping groove at the starting point and the damping groove at the end point in the direction of conveying the rubber along the screw groove. The first flow limiting plate is configured to cooperate with the damping groove to change the normal spiral conveying state of the rubber so as to force the rubber to be squeezed through the damping groove.

[0014] In an optional embodiment of the present application, a second flow limiting plate is further provided in the screw groove of the screw exhaust section, which is arranged 180° opposite to the first flow limiting plate in the spiral ring direction and can prevent the rubber material that has been squeezed through the damping groove from flowing back. The first flow limiting plate and the second flow limiting plate are arranged in sequence according to the forward direction of the screw's spiral conveying of the rubber material.

[0015] In an optional embodiment of the present application, the bottom ends of the first current limiting plate and the second current limiting plate are connected to the bottom surface of the screw groove, the first current limiting plate and the second current limiting plate have the same height, and the top ends of the first current limiting plate and the second current limiting plate are respectively flush with the end faces of the screw ridges at their respective positions.

[0016] In an optional manner of the present application, the screw includes a screw feeding section, a screw plasticizing section, a screw exhaust section and a screw extrusion section arranged in sequence along the feeding direction, the screw feeding section, the screw plasticizing section, the screw exhaust section and the screw extrusion section respectively correspond to the feeding section, plasticizing section, exhaust section and extrusion section of the barrel, the screw feeding section is a composite structure of four-start threads and double-start threads, the screw plasticizing section is provided with a pin groove, and pins are evenly inserted on the barrel walls corresponding to the plasticizing section and the extrusion section of the barrel, and the screw plasticizing section, the screw exhaust section and the screw extrusion section are double-start equidistant threads.

[0017] On the other hand, the present application also provides a pin cold feed exhaust extruder, which is equipped with the extruder exhaust screw proposed in the present application.

[0018] In an optional manner of the present application, a vacuum port is provided in the exhaust section of the barrel of the extruder, and the vacuum port is connected to a vacuum pump.

[0019] Compared with the prior art, this application has the following beneficial effects:

[0020] The present application provides an extruder exhaust screw and a pin cold feed exhaust extruder, wherein a screw exhaust section capable of accelerating the exhaust of gas in the rubber material is arranged in the area corresponding to the exhaust section of the screw barrel, and a plurality of damping grooves which are consistent with the length direction of the screw and can perform beading and shearing effects on the rubber material are arranged on the spiral edge end face of the screw exhaust section. The presence of the plurality of damping grooves can enable the rubber material which was originally normally conveyed in the spiral groove of the screw to enter the plurality of damping grooves when conveyed to the area of ​​the screw exhaust section with the damping grooves. Since the damping grooves are arranged in a direction consistent with the length direction of the screw, and the length of the damping grooves themselves is limited by the size of the spiral edge end face of the screw exhaust section, the length of each damping groove is relatively limited, so that on the one hand, it can The rubber normally conveyed in the screw groove can enter the damping groove more easily. On the other hand, the rubber entering the damping groove can quickly pass through the damping groove with limited length, reducing the time the rubber in the damping groove stays in the damping groove. In this process, the rubber will be pressed into multiple damping grooves during transportation, and the rubber will be diverted to achieve the pressure stripping effect on the rubber. In addition, the exhaust section of the screw uses the effect of the damping groove on the continuous rotation of the screw itself to quickly cut off the thin strip of rubber after passing through the damping groove to discharge the remaining gas in the rubber, thereby strengthening the exhaust section of the screw to discharge the gas in the rubber to prevent it from entering the preform. Such continuous pressure stripping and shearing action significantly improves the exhaust effect on the rubber, thereby reducing the pore defects of rubber products. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 A schematic diagram of the structure of an exhaust screw for an extruder provided in one embodiment of the present application;

[0023] Figure 2 One of the schematic diagrams of the screw plasticizing section provided in one embodiment of the present application;

[0024] Figure 3 The second schematic diagram of the screw plasticizing section provided in one embodiment of the present application;

[0025] Figure 4 The third schematic diagram of the screw plasticizing section provided in one embodiment of the present application;

[0026] Figure 5 A schematic structural diagram of a pin cold feed exhaust extruder provided in one embodiment of the present application.

[0027] Reference numerals:

[0028] 1. Barrel;

[0029] 2. Screw;

[0030] 21. Screw feeding section;

[0031] 22. Screw plasticizing section;

[0032] 23. Screw exhaust section;

[0033] 24. Screw extrusion section;

[0034] 3. Damping groove;

[0035] 4. Screw groove;

[0036] 5. The first current limiting sheet;

[0037] 6. The second current limiting plate;

[0038] 7. Pins;

[0039] 8. Vacuum port;

[0040] 9. Vacuum pump;

[0041] 10. Temperature controller. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work also fall within the scope of protection of the present application.

[0043] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0044] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0045] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0046] An embodiment of the present application provides an extruder exhaust screw, which is applied to a single-screw pin cold feed exhaust extruder.

[0047] like Figure 1-Figure 4 As shown, the exhaust screw of the extruder includes a screw 2 installed in a barrel 1 of the extruder; the screw 2 is provided with a screw exhaust section 23 capable of accelerating the exhaust of gas in the rubber material in the area corresponding to the exhaust section of the barrel 1, and a plurality of damping grooves 3 which are consistent with the length direction of the screw 2 and can press and shear the rubber material are opened on the end face of the screw ridge of the screw exhaust section 23, and the screw exhaust section 23 is configured to cut off the rubber material passing through the damping groove 3 under the rotation of the screw 2 with the help of the damping groove 3 to exhaust the gas in the rubber material.

[0048] The extruder exhaust screw provided in the embodiment of the present application can be obtained by making structural improvements on the screw used in the traditional pin cold feed exhaust extruder.

[0049] Specifically, the present application is implemented by a simple structural improvement on the screw exhaust section 23 of the screw 2. The structural design of the present application is reasonable. A screw exhaust section 23 capable of accelerating the discharge of gas in the rubber material is provided in the area corresponding to the exhaust section of the barrel 1 of the screw 2. A plurality of damping grooves 3 are provided on the end face of the screw ridge of the screw exhaust section 23, which are consistent with the length direction of the screw 2 and can perform beading and shearing effects on the rubber material. The presence of the plurality of damping grooves 3 can enable the rubber material that was originally normally conveyed in the screw groove of the screw 2 to enter the plurality of damping grooves 3 when it is conveyed to the area of ​​the screw exhaust section 23 having the damping grooves 3, thereby providing a strong structural basis for improving the exhaust effect of the screw exhaust section 23 on the rubber material.

[0050] Since the damping groove 3 is arranged in a direction consistent with the length direction of the screw 2, and the length of the damping groove 3 itself is limited by the size of the end face of the screw rib of the exhaust section 23 of the screw, the length of each damping groove 3 is relatively limited. In this way, on the one hand, the rubber normally conveyed in the screw groove can enter the damping groove 3 more easily. On the other hand, the rubber entering the damping groove 3 can quickly pass through the damping groove 3 with a limited length, reducing the time the rubber in the damping groove 3 stays in the damping groove 3. In this process, the rubber will be pressed into multiple damping grooves during transportation. In the groove 3, the rubber material is diverted to achieve the beading effect on the rubber material, and the screw exhaust section 23, with the help of the damping groove 3 and the continuous rotation of the screw 2 itself, quickly cuts off the thin strip of rubber material after passing through the damping groove 3 to discharge the residual gas in the rubber material, thereby strengthening the screw exhaust section 23 to discharge the gas in the rubber material to prevent it from entering the preform. Such continuous beading and shearing action significantly improves the exhaust effect of the rubber material, and discharges a large amount of air and other gases entrained by the feed from the rubber material, thereby reducing the pore defects of rubber products.

[0051] As an optional method of the embodiment of the present application, the damping grooves 3 are arranged in a spiral shape and are evenly opened on the spiral edge end face of the screw exhaust section 23, and the damping grooves 3 are evenly distributed on the spiral edge end face corresponding to a pitch length range of the screw exhaust section 23.

[0052] In the embodiment of the present application, the damping grooves 3 are arranged in a spiral shape and are evenly opened on the end face of the screw ridge of the screw exhaust section 23, so that it can better adapt to the original spiral conveying state of the rubber in the screw groove. In the present application, when the rubber is pushed into multiple damping grooves 3 by spiral conveying, it is not squeezed into multiple damping grooves 3 at the same length position (position in the length direction of the screw), nor is it squeezed out of multiple damping grooves 3 at the same length position (position in the length direction of the screw). In this way, the rubber will not be excessively concentrated in the length direction of the screw when it is squeezed into the damping groove 3 and when it is extruded out of the damping groove 3, but will be dispersed, which helps to improve the extrusion smoothness of the rubber at the damping groove 3, thereby avoiding the situation of poor discharge of the damping groove 3 and poor feeding of the rubber after it is extruded from the damping groove 3.

[0053] Optionally, the damping groove 3 is an arc-shaped groove with a semicircular cross section. In the embodiment of the present application, the damping groove 3 adopts an arc-shaped groove structure with a semicircular cross section. On the one hand, this structure is convenient for processing on the end face of the screw fin. On the other hand, this arc-shaped groove type damping groove 3 design helps to improve the extrusion smoothness of the rubber in the damping groove 3 and improve the situation where the rubber blocks the damping groove 3.

[0054] In one embodiment of the present application, the interval width between adjacent damping grooves 3 is 0.8-1.2 times the normal width of the screw flight, and the width of the damping groove 3 is 0.2-0.5 times the normal width of the screw flight.

[0055] In the embodiment of the present application, by selecting a suitable interval width between adjacent damping grooves 3 and selecting a suitable width in conjunction with the damping grooves 3, the area of ​​the screw exhaust section 23 where the damping grooves 3 are set can be more efficiently utilized to arrange the damping grooves 3 of suitable width, thereby efficiently and smoothly extruding the rubber into strips, thereby avoiding the situation where the damping grooves 3 are relatively large in width and the damping grooves 3 are not discharged smoothly due to the large specifications of the extruded strips. At the same time, it also avoids the situation where the rubber strips discharged from the damping grooves 3 are difficult to cooperate with the rotation of the screw and the rubber strips are completely and quickly cut off.

[0056] At the same time, the embodiment of the present application does not minimize the spacing width between the damping grooves 3 and the width of the damping grooves 3. This is because the setting of the damping grooves 3 with too dense spacing is not only not conducive to the rapid cutting of the rubber strip after passing through the damping grooves 3, but also the setting of the damping grooves 3 with too dense spacing and the damping grooves 3 with smaller widths will increase the resistance of the rubber extrusion process, which is not conducive to the smooth extrusion of the rubber and also increases the probability of the damping grooves 3 being blocked by the rubber.

[0057] In one embodiment of the present application, a first flow limiting plate 5 is provided in the screw groove 4 corresponding to the damping groove 3 opened on the end face of the screw ridge of the screw exhaust section 23, and the first flow limiting plate 5 is connected to the screw groove 4 between the damping groove 3 at the starting point and the damping groove 3 at the end point in the direction of conveying the rubber along the screw groove 4. The first flow limiting plate 5 is configured to cooperate with the damping groove 3 to change the normal spiral conveying state of the rubber so as to force the rubber to be squeezed through the damping groove 3.

[0058] In this embodiment, in addition to the damping groove 3 provided on the end face of the screw rib, the screw exhaust section 23 is also provided with a first flow limiting plate 5 in the screw groove 4 corresponding to the damping groove 3. The first flow limiting plate 5 is in the same direction as the damping groove 3 and is connected to the screw groove 4 between the damping groove 3 at the start and the end of the direction of conveying the rubber material along the screw groove 4. The additional design of this structure enables the rubber material in the screw groove 4 that is normally spirally conveyed to be blocked by the first flow limiting plate 5 when passing through the part of the screw exhaust section 2 that is provided with the damping groove 3, so that the rubber material that is normally spirally conveyed is suspended from normal spiral conveying and no longer conveyed along the screw groove, thereby changing the normal spiral conveying state of the rubber material and forcing the rubber material to be squeezed through the damping groove 3.

[0059] The blocking effect of the first flow limiting plate 5 on the rubber at the appropriate position enables the rubber to be extruded through the damping groove 3 to a great extent, so that the rubber can be cut into thin strips more completely after extrusion, thereby more completely discharging the gas in the rubber.

[0060] Optionally, a second flow limiting plate 6 is further provided in the screw groove 4 of the screw exhaust section 23, which is arranged 180° opposite to the first flow limiting plate 5 in the spiral ring direction and can prevent the rubber material that has been squeezed through the damping groove 3 from flowing back. The first flow limiting plate 5 and the second flow limiting plate 6 are arranged in sequence according to the forward direction of the screw's spiral conveying of the rubber material.

[0061] During use, the rubber is blocked by the first flow limiting plate 5 and then squeezed into the damping groove 3. The rubber strip squeezed out of the damping groove 3 is then quickly cut off under the action of the screw rotation. The finer rubber obtained after cutting falls into the screw groove and continues to be spirally conveyed. In order to prevent the rubber from flowing back to a large extent after being squeezed and quickly cut through the damping groove 3, a second flow limiting plate 6 is also provided in the embodiment of the application. The first flow limiting plate 5 and the second flow limiting plate 6 are arranged in sequence according to the forward direction of the spiral conveying of the rubber by the screw, that is, according to the direction of rubber conveying, the first flow limiting plate 5 is provided first, and then the second flow limiting plate 6 is provided. The second flow limiting plate 6 here not only restricts the backflow of the rubber, but also gathers the fine rubber obtained after quick cutting after flowing back, so that the rubber is further evenly mixed and the heat exchange of the rubber is more sufficient, so as to facilitate the subsequent further spiral conveying.

[0062] Optionally, the bottom ends of the first current limiting piece 5 and the second current limiting piece 6 are connected to the bottom surface of the screw groove 4, so as to avoid a gap between the bottom end of the first current limiting piece 5 and the bottom surface of the screw groove 4 and between the bottom end of the second current limiting piece 6 and the bottom surface of the screw groove 4, which causes the rubber to flow away from the gap. The first current limiting piece 5 and the second current limiting piece 6 have the same height and the top ends of the first current limiting piece 5 and the second current limiting piece 6 are respectively flush with the end faces of the screw ridges at their respective positions, so as to better play a blocking or converging role.

[0063] In one embodiment of the present application, the screw 2 includes a screw feeding section 21, a screw plasticizing section 22, a screw exhaust section 23 and a screw extrusion section 24 arranged in sequence along the feeding direction, the screw feeding section 21, the screw plasticizing section 22, the screw exhaust section 23 and the screw extrusion section 24 respectively correspond to the feeding section, plasticizing section, exhaust section and extrusion section of the barrel 1, the screw feeding section 21 is a composite structure of four-start threads and double-start threads, the screw plasticizing section 22 is provided with a pin groove, and pins 7 are evenly inserted on the barrel wall corresponding to the plasticizing section and the extrusion section of the barrel 1, and the screw plasticizing section 22, the screw exhaust section 23 and the screw extrusion section 24 are double-start equidistant threads. When in use, the rubber is fed into the barrel 1 through the feeding port of the extruder, and the rubber is quickly eaten into the screw groove of the screw 2. The rubber entering the feeding section of the barrel 1 is continuously conveyed to the plasticizing section of the barrel 1 under the spiral conveying action of the screw 2. In the plasticizing section, the barrel 1 is inserted with a pin 7 as a plasticizing element to fully and evenly plasticize the rubber in the screw groove of the screw 2. Then the rubber is conveyed to the exhaust section of the barrel 1. In this section of the barrel 1, the advantages of the exhaust screw of the extruder provided in the embodiment of the present application are fully utilized. The screw exhaust section 23 is used to exhaust the conveyed rubber. During the process, the rubber is stripped and sheared to fully release the air and volatile gas involved in the rubber feeding. The exhausted rubber is then conveyed to the screw extrusion section 24 and sufficient pressure is established to extrude the required product through the molding head of the extruder.

[0064] like Figure 5 As shown, an embodiment of the present application also provides a pin cold feed exhaust extruder, which is equipped with the extruder exhaust screw provided by the above-mentioned embodiment of the present application.

[0065] In one embodiment of the present application, the exhaust section of the barrel 1 of the extruder is provided with a vacuum port 8, such as Figure 1 and Figure 5As shown, the vacuum port 8 is connected to a vacuum pump 9. During the conveying process of the rubber in the screw extrusion section 24 of the screw 2, the air and volatile gas involved in the rubber and the moisture in the rubber can be extracted by the vacuum pump, so that the rubber product has no pores, thereby increasing the service life of the rubber product. In specific applications, the extruder can be equipped with a four-zone temperature control according to actual conditions, and four temperature controllers 10 can be added to control the functional areas of the extruder for better application.

[0066] As an optional method of the embodiment of the present application, the screw exhaust section 23 has the minimum length interval section of all the damping grooves 3 and is set to the side of the plasticizing section of the barrel 1. Such a structural setting can enable the rubber to be transported into the screw exhaust section 23 in time after plasticization, so as to implement the extrusion and shearing action unique to the present application as soon as possible to discharge the gas in the rubber. Since the rubber contains not only the air involved in the feed, but also some volatile gases and possible moisture generated by the vulcanization reaction of the rubber at high temperature, all these gases must be discharged in time, otherwise, the retention of these gases will bring potential risks to the quality of the product. For this reason, the embodiment of the present application arranges the screw exhaust section 23 that can accelerate the gas discharge in time after the plasticizing section of the barrel 1 and sets the minimum length interval section of the damping groove 3 to the side of the plasticizing section of the barrel 1, so that the gas can be discharged in time to improve the exhaust effect of the entire screw exhaust section 23.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An extruder exhaust screw, characterized in that: The extruder exhaust screw is applied to a single-screw pin cold-feed exhaust extruder, and the extruder exhaust screw comprises a screw (2) installed in a barrel (1) of the extruder; The screw (2) is provided with a screw exhaust section (23) capable of accelerating the exhaust of gas in the rubber material in the area corresponding to the exhaust section of the barrel (1); a plurality of damping grooves (3) which are consistent with the length direction of the screw (2) and can press and shear the rubber material are opened on the screw edge end face of the screw exhaust section (23); the screw exhaust section (23) is configured to cut off the rubber material passing through the damping groove (3) under the rotation of the screw (2) by means of the damping groove (3) to exhaust the gas in the rubber material.

2. The exhaust screw of the extruder according to claim 1, characterized in that: The damping grooves (3) are arranged in a spiral shape and are evenly opened on the screw edge end face of the screw exhaust section (23), and the damping grooves (3) are evenly distributed on the screw edge end face corresponding to a pitch length range of the screw exhaust section (23).

3. The exhaust screw of the extruder according to claim 2, characterized in that: The damping groove (3) is an arc-shaped groove with a semicircular cross section.

4. The exhaust screw of the extruder according to claim 3, characterized in that: The spacing width between adjacent damping grooves (3) is 0.8-1.2 times the normal width of the screw fin, and the width of the damping groove (3) is 0.2-0.5 times the normal width of the screw fin.

5. The exhaust screw of the extruder according to any one of claims 1 to 4, characterized in that: The screw exhaust section (23) has a screw groove (4) corresponding to the damping groove (3) on the end face of the screw ridge, and a first flow limiting plate (5) is arranged in the same direction as the damping groove (3) and capable of limiting the spiral conveying of the rubber material in the screw groove. The first flow limiting plate (5) is connected to the screw groove (4) between the damping groove (3) at the starting point and the damping groove (3) at the end point in the direction of conveying the rubber material along the screw groove (4). The first flow limiting plate (5) is configured to cooperate with the damping groove (3) to change the normal spiral conveying state of the rubber material so as to force the rubber material to be squeezed through the damping groove (3).

6. The exhaust screw of the extruder according to claim 5, characterized in that: A second flow limiting plate (6) is also provided in the screw groove (4) of the screw exhaust section (23), which is arranged 180 degrees opposite to the first flow limiting plate (5) in the spiral ring direction and can prevent the rubber material that has been squeezed through the damping groove (3) from flowing back. The first flow limiting plate (5) and the second flow limiting plate (6) are arranged in sequence according to the forward direction of the screw's spiral conveying of the rubber material.

7. The exhaust screw of the extruder according to claim 6, characterized in that: The bottom ends of the first current limiting plate (5) and the second current limiting plate (6) are connected to the bottom surface of the screw groove (4), the first current limiting plate (5) and the second current limiting plate (6) have the same height, and the top ends of the first current limiting plate (5) and the second current limiting plate (6) are respectively flush with the end surfaces of the screw ridges at their respective positions.

8. The exhaust screw of the extruder according to claim 6 or 7, characterized in that: The screw (2) comprises a screw feeding section (21), a screw plasticizing section (22), a screw exhaust section (23) and a screw extrusion section (24) which are arranged in sequence along the feeding direction. The screw feeding section (21), the screw plasticizing section (22), the screw exhaust section (23) and the screw extrusion section (24) respectively correspond to the feeding section, plasticizing section, exhaust section and extrusion section of the barrel (1). The screw feeding section (21) is a composite structure of four-start threads and double-start threads. The screw plasticizing section (22) is provided with a pin groove. Pins (7) are evenly inserted on the barrel wall corresponding to the plasticizing section and the extrusion section of the barrel (1). The screw plasticizing section (22), the screw exhaust section (23) and the screw extrusion section (24) are double-start equidistant threads.

9. A pin cold feed venting extruder, characterized in that: The extruder exhaust screw according to any one of claims 1 to 8 is installed.

10. The pin cold feed venting extruder according to claim 9, characterized in that: The exhaust section of the barrel (1) of the extruder is provided with a vacuum port (8), and the vacuum port (8) is connected to a vacuum pump (9).

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