CN111037881A

CN111037881A - Method for controlling extrusion compactness of desulfurized rubber powder

Info

Publication number: CN111037881A
Application number: CN201911399822.0A
Authority: CN
Inventors: 董大伟; 江宽; 武晋巍; 许红卫
Original assignee: Beijng Environmental Protection Technology Co Ltd Wing Tai Luther
Current assignee: Beijng Environmental Protection Technology Co Ltd Wing Tai Luther
Priority date: 2019-12-30
Filing date: 2019-12-30
Publication date: 2020-04-21

Abstract

The application relates to the technical field of rubber powder processing, and discloses a method for controlling the extrusion compactness of desulfurized rubber powder, which comprises the following steps: the first process is as follows: a plurality of reverse helical blades a are arranged on a first screw in a double-screw extruder at intervals, the outer diameter of each reverse helical blade a is smaller than that of each forward helical blade a on the first screw, and the forward helical blades a and the reverse helical blades a on the first screw generate thrust in opposite directions on materials to extrude the materials and simultaneously convey the materials forwards integrally; and a second process: arranging a plurality of extrusion openings in the double-screw extruder, so that the materials pass through the extrusion openings in the conveying process, and further extruding the materials by using the extrusion openings; the third process: before the materials are conveyed from the double-screw extruder to the single-screw extruder, the materials are scattered. This scheme can let the material more closely knit in double screw extruder, and is looser in single screw extruder, has satisfied the processing needs.

Description

Method for controlling extrusion compactness of desulfurized rubber powder

Technical Field

The invention belongs to the technical field of rubber powder processing.

Background

The method comprises the steps of recovering waste tires, then generally preparing the waste tires into rubber particles, uniformly mixing the rubber particles, a regenerant and other materials, extruding and processing the uniformly mixed materials by a double-screw extruder, feeding the materials processed by the double-screw extruder into a single-screw extruder, then extruding and processing the materials, and finally obtaining the regenerated rubber.

Rubber particles are mixed and extruded in a double-screw extruder, the compactness of materials needs to be improved, but the processed semi-finished products are in a loose state, so the materials extruded in a single-screw extruder need to be in a loose state, the compactness of the materials extruded in the existing double-screw extruder is insufficient, the compactness of the materials extruded by the single-screw extruder is also high, and the requirement of material processing cannot be met.

Disclosure of Invention

The invention aims to provide a method for controlling the extrusion compactness of desulfurized rubber powder, which aims to solve the problems of insufficient compactness of materials in a double-screw extruder and insufficient looseness of the materials in a single-screw extruder.

In order to achieve the purpose, the basic scheme of the invention provides a method for controlling the extrusion compactness of desulfurized rubber powder, which comprises the following steps:

the first process is as follows: a plurality of reverse helical blades a are arranged on a first screw in a double-screw extruder at intervals, the outer diameter of each reverse helical blade a is smaller than that of each forward helical blade a on the first screw, and the forward helical blades a and the reverse helical blades a on the first screw generate thrust in opposite directions on materials to extrude the materials and simultaneously convey the materials forwards integrally;

and a second process: arranging a plurality of extrusion openings in the double-screw extruder, so that the materials pass through the extrusion openings in the conveying process, and further extruding the materials by using the extrusion openings;

the third process: before the materials are conveyed from the double-screw extruder to the single-screw extruder, the materials are scattered.

The principle and the beneficial effect of the basic scheme are as follows:

this scheme is in double screw extruder, through reverse helical blade an's setting, lets forward helical blade an and reverse helical blade a produce opposite direction's thrust to the material, extrudees the material, the closely knit degree increase of material to closely knit degree after the material ejection of compact has been improved. And because the external diameter of reverse helical blade a is less than the external diameter of forward helical blade a, consequently, reverse helical blade a is less than the effort that forward helical blade a applyed the material, consequently, the material in the feed cylinder is forward movement on the whole. Meanwhile, because the material returns, the retention time of the material in the charging barrel is prolonged, so that the material is fully mixed and reacted in the charging barrel. When the material passes through the extrusion mouth, the material is by further extrusion, further promotes the closely knit degree of material. And when the materials enter the single-screw extruder from the double-screw extruder, the materials are scattered, the compactness of the materials in the single-screw extruder is reduced, the materials are loosened, and the materials discharged from the single-screw extruder are in a loose state, so that the requirements of material processing are met.

This scheme can let the material more closely knit in double screw extruder, and is looser in single screw extruder, has satisfied the processing needs.

Optionally, in the first process, a plurality of reverse helical blades b are arranged on the second screw of the twin-screw extruder at intervals, and the outer diameter of each reverse helical blade b is smaller than that of each forward helical blade b on the second screw.

In the process of forward movement of the material, the reverse helical blade b pushes the material to move reversely (return), so that the material is subjected to axial extrusion force, and the compactness of the material is further improved.

Optionally, grooves are formed on the surfaces of the reverse helical blade a and the reverse helical blade b, so that the surfaces of the reverse helical blade a and the reverse helical blade b are uneven.

The grooves are arranged so that the surfaces of the reverse helical blade a and the reverse helical blade b are uneven. In the process of pushing the materials, the rotating directions of the reverse spiral blade a and the reverse spiral blade b are opposite, so that the materials positioned between the reverse spiral blade a and the reverse spiral blade b can be subjected to stronger shearing force, and the mixing and the reaction of the materials are more facilitated.

Optionally, in the second process, the material is beaten when passing through the extrusion opening.

Through the limiting effect of the extrusion opening, the material is further extruded when passing through the extrusion opening, and the compactness of the material is further improved. And when the material passes through the extrusion opening, the material is beaten and tamped, so that the compactness of the material is further improved.

Optionally, the method further comprises a flue gas treatment process: and the flue gas treatment unit is used for timely discharging the vulcanized flue gas in the double-screw extruder.

The rubber powder is desulfurized in the charging barrel after being heated, the sulfuration flue gas can be generated in the process, and if the sulfuration flue gas enters the material, the material can generate the defects of bubbles and the like, so that the density of the material is greatly adversely affected. This scheme utilization flue gas processing unit in time discharges away the vulcanize flue gas that produces in the double screw extruder, can avoid producing the bubble in the material, has further promoted the closely knit degree of material.

Optionally, the twin-screw extruder comprises a driving motor, a rotating shaft, a charging barrel, a first screw and a second screw, wherein the first screw is provided with a forward helical blade a and a reverse helical blade a, the outer diameter of the reverse helical blade a is smaller than that of the forward helical blade a, the second screw is provided with a forward helical blade b and a reverse helical blade b, and the outer diameter of the reverse helical blade b is smaller than that of the forward helical blade b; a plurality of spacing blocks are arranged in the charging barrel, a first screw and a second screw penetrate through the spacing blocks and are rotationally connected with the spacing blocks, extrusion openings are formed in the spacing blocks, and striking units used for striking materials at the extrusion openings are arranged on the spacing blocks; the charging barrel is also provided with a smoke treatment unit.

The forward helical blade a and the forward helical blade b push materials in the charging barrel to move forward, the reverse helical blade a and the reverse helical blade b push the materials in the charging barrel to move reversely (return), and the outer diameter of the reverse helical blade a is smaller than that of the forward helical blade a, and the outer diameter of the reverse helical blade b is smaller than that of the forward helical blade b, so that the acting force applied to the materials by the reverse helical blade a is smaller than that of the forward helical blade a, and the acting force applied to the materials by the reverse helical blade b is smaller than that of the forward helical blade b. Therefore, the material in the charging barrel moves forward on the whole, and in the process of moving forward, the material is subjected to axial extrusion force, the compactness of the material is increased, and the compactness of the material after discharging is improved. Meanwhile, because the material returns, the retention time of the material in the charging barrel is prolonged, so that the material is fully mixed and reacted in the charging barrel.

The material need pass through a plurality of extrusion mouth in the data send process, because the size of extrusion mouth is fixed, so the material can through the extrusion mouth time, friction between the material, extrusion are more abundant, further promote the closely knit degree of material. The beating unit beats and hammers the materials passing through the extrusion opening, so that the compactness of the materials is further improved.

Optionally, the striking unit comprises a movable cavity arranged in the spacer block, the second screw penetrates through the movable cavity and is provided with sector teeth, a driven shaft is rotatably connected in the movable cavity, a push rod and a matched gear meshed with the sector teeth are arranged on the driven shaft, a striking plate is slidably connected to the bottom of the movable cavity, a first elastic piece is connected to the top of the striking plate, and the first elastic piece is fixed in the movable cavity; the bottom of the striking plate can slide out of the movable cavity and enter the extrusion opening.

The second screw rod drives the driven shaft, the matching gear and the push rod to rotate through the sector gear in the rotating process, so that the beating plate is intermittently pushed out, and the material on the extruding opening is beaten and tamped, so that the compactness of the material is improved.

Optionally, the flue gas treatment unit comprises a first gear fixedly connected to the rotating shaft, the first gear is engaged with a second gear, and the second gear is coaxially and fixedly connected with a cam; a cylinder body is fixedly arranged below the rotating shaft, a piston is vertically and slidably connected in the cylinder body, the cylinder body is divided into an upper chamber and a lower chamber by the piston, the cam is positioned in the upper chamber and abuts against the piston, the top wall of the upper chamber is fixedly connected with a plurality of second elastic pieces, and one end, far away from the top wall of the upper chamber, of each second elastic piece is fixedly connected with the piston; the lower cavity is communicated with an air inlet pipe and an air outlet pipe, a first one-way valve for guiding air into the lower cavity is fixedly mounted on the air inlet pipe, one end, away from the lower cavity, of the air inlet pipe is communicated with the charging barrel, the communicated position of the air inlet pipe and the charging barrel is located at the same side with the feeding hole, and a second one-way valve for guiding air out of the lower cavity is fixedly mounted on the air outlet pipe.

By utilizing the flue gas treatment unit, the vulcanized flue gas generated in the double-screw extruder is discharged in time, so that bubbles generated in the material can be avoided, and the compactness of the material is further improved. The method specifically comprises the following steps: utilize first gear and second gear meshing for the cam takes place to rotate, thereby make the piston take place reciprocal slip from top to bottom under the effect of cam and second elastic component, the volume of lower cavity constantly changes, inhales the lower cavity with the vulcanization flue gas that produces in the feed cylinder in through the intake pipe, carries the vulcanization flue gas to flue gas processing apparatus through the outlet duct again, avoids the vulcanization flue gas to cause the material to produce the bubble on the one hand, and on the other hand also can avoid the vulcanization flue gas directly to discharge to the atmosphere in, harm health and environment.

Optionally, the single screw extruder comprises a barrel, a single screw and a feed pipe, the feed pipe being provided with the breaker unit.

The feed pipe is provided with the breaking unit, so that the material with larger compactness discharged from the double-screw extruder can be broken up, the material is loosened, and the compactness of the material in the single-screw extruder is reduced.

Optionally, break up the unit and include that the level rotates the dwang of connection on the inlet pipe, be fixed with a plurality of on the dwang and break up the pole, be connected with driving belt between dwang and the single screw rod tip.

The single screw rod passes through driving belt and drives the dwang and rotate, and the dwang drives and breaks up the continuous rotation of pole, breaks up the processing to the material through this inlet pipe to reduce the closely knit degree of material in single screw extruder, let the material loose, and then let the material of following discharge in single screw extruder be in loose state.

Drawings

FIG. 1 is a schematic structural diagram of a twin-screw extruder in the method for controlling the extrusion compactness of the desulfurized rubber powder according to the invention;

FIG. 2 is a schematic structural view of a first screw and a second screw;

FIG. 3 is a longitudinal cross-sectional view of the spacer of FIG. 1;

FIG. 4 is a top cross-sectional view of the spacer of FIG. 1;

FIG. 5 is a schematic view of the structure of a single screw extruder.

Detailed Description

The following is further detailed by way of specific embodiments:

reference numerals in the drawings of the specification include: the device comprises a driving motor 1, a charging barrel 2, a first screw rod 3, a second screw rod 4, a rotating shaft 5, a transmission belt 6, a forward spiral blade a7, a reverse spiral blade a8, a forward spiral blade b9, a feeding hole 10, a discharging hole 11, a heating section I12, a heating section II 13, a heating section III 14, a heating section IV 15, a heat preservation section 16, a cooling section I17, a cooling section II 18, a first gear 19, a second gear 20, a cam 21, a piston 22, an upper chamber 23, a lower chamber 24, a second elastic member 25, an air inlet pipe 26, an air outlet pipe 27, a reverse spiral blade b28, a groove 29, a spacing block 30, a movable chamber 31, a sector gear 32, a matching gear 33, a push rod 34, a striking plate 35, a squeezing port 36, a feeding pipe 37, a feeding pipe 38, a single screw rod 39, a rotating rod 40 and a striking rod 41.

Example 1

The method for controlling the extrusion compactness of the desulfurized rubber powder comprises the following steps:

the first process is as follows: a plurality of reverse helical blades a8 are arranged on the first screw 3 of the twin-screw extruder at intervals, and the outer diameter of the reverse helical blade a8 is smaller than that of the forward helical blade a7 on the first screw 3; the forward helical blade a7 and the reverse helical blade a8 on the first screw rod 3 generate thrust in opposite directions to the material, so that the material is extruded, and meanwhile, the whole material is conveyed forwards; a plurality of reverse helical blades b28 are arranged on a second screw 4 of the double-screw extruder at intervals, the outer diameter of the reverse helical blade b28 is smaller than that of a forward helical blade b9 on the second screw 4, and the forward helical blade b9 and the reverse helical blade b28 generate reverse thrust on the material to extrude the material and convey the material forwards integrally.

The surfaces of the reverse helical blade a8 and the reverse helical blade b28 are both provided with grooves 29, so that the surfaces of the reverse helical blade a8 and the reverse helical blade b28 are uneven.

And a second process: a plurality of extrusion ports 36 are disposed in the twin screw extruder to allow the material to pass through the extrusion ports 36 during the conveying process, the extrusion ports 36 are used to further extrude the material, and the material is beaten as it passes through the extrusion ports 36.

The third process: the material is broken up before being conveyed from the twin screw extruder to the single screw 39 extruder.

In this embodiment, as shown in fig. 1 and fig. 2, the twin-screw extrusion device includes a driving motor, a charging barrel 2, a first screw 3, and a second screw 4, an output end of the driving motor is coaxially and fixedly connected with a rotating shaft 5, and a right end of the rotating shaft 5 is connected with the first screw 3 through a coupling. The first screw 3 and the second screw 4 are driven by a belt 6. The first screw 3 is integrally formed with a forward spiral blade a7 and a reverse spiral blade a8, the outer diameter of the reverse spiral blade a8 is smaller than that of the forward spiral blade a7, and the length of the reverse spiral blade a8 is shorter than that of the forward spiral blade a 7. The second screw 4 is integrally formed with a forward spiral blade b 9. The forward spiral blade a7 and the reverse spiral blade a8 on the first screw 3 are arranged at intervals with the forward spiral blade b9 on the second screw 4.

The forward helical blade a7, the reverse helical blade a8, the forward helical blade b9 and the reverse helical blade b28 are all positioned in the barrel 2, the left end of the barrel 2 is communicated with a feed inlet 10, and the feed inlet 10 is positioned above the head of the forward helical blade b9 of the second screw 4; the right end of the charging barrel 2 is communicated with a discharge port 11, and the discharge port 11 is positioned below the tail part of the forward helical blade b9 of the second screw 4. The charging barrel 2 is divided into a heating section, a heat preservation section 16 and a cooling section I17 along the axial direction, the heating section comprises a heating section II 13, a heating section III 14, a heating section IV 15, a heating section I12, a heating section II 13, a heating section III 14 and a heating section IV 15, the heating temperature is gradually increased, and the cooling section comprises a cooling section I17 and a cooling section II 18. In this example, the temperature of the heating section i 12 is 200 ℃, the temperature of the heating section ii 13 is 250 ℃, the temperature of the heating section iii 14 is 280 ℃, the temperature of the heating section iv 15 is 305 ℃, the temperature of the holding section 16 is 305 ℃, the temperature of the cooling section i 17 is 280 ℃, and the temperature of the cooling section ii 18 is 250 ℃.

A plurality of spacing blocks 30 are installed in the charging barrel 2, and as shown in the attached

drawings

3 and 4, the first screw 3 and the second screw 4 both penetrate through the spacing blocks 30 and are rotatably connected with the spacing blocks 30, and an extrusion opening 36 is formed in the middle of each spacing block 30. The spacing block 30 is provided with a striking unit for striking materials at the extrusion port 36, the striking unit mainly comprises a movable cavity 31, a sector gear 32, a driven shaft, a matching gear 33, a push rod 34, a striking plate 35 and a first elastic part, the movable cavity 31 is arranged in the spacing block 30, the second screw rod 4 penetrates through the movable cavity 31, and the sector gear 32 is arranged on the position of the second screw rod 4 penetrating through the movable cavity 31. The driven shaft is horizontally and rotatably connected in the movable cavity 31, the matching gear 33 and the push rod 34 are both arranged on the driven shaft, and the matching gear 33 is meshed with the sector teeth 32. The striking plate 35 is vertically connected to one side of the movable cavity 31 in a sliding manner, the bottom of the side of the movable cavity 31 is communicated with the extrusion port 36, and the striking plate 35 can slide out of the movable cavity 31 and enter the extrusion port 36; the top of the striking plate 35 is fixedly connected with two first elastic members, the first elastic members are fixed on the inner wall of the movable cavity 31, and the first elastic members are springs. The push rod 34 abuts against the top of the beating plate 35 in the rotating process and pushes the beating plate 35 to slide downwards, so that materials at the extrusion opening 36 are beaten and tamped.

Referring to FIG. 5, the single-screw 39 extruder is mainly composed of a cylinder 37, a single screw 39, a feed pipe 38 and a breaking unit, wherein the single screw 39 is positioned in the cylinder 37, and the feed pipe 38 is positioned at the left side of the cylinder 37 and connected with a discharge port 11 of the twin-screw extruder. The scattering unit mainly comprises a rotating rod 40, a plurality of scattering rods 41 and a conveying belt, wherein the rotating rod 40 is horizontally and rotatably connected in the feeding pipe 38, and the plurality of scattering rods 41 are uniformly distributed on the rotating rod 40 and used for scattering materials passing through the feeding pipe 38; the rotating rod 40 is connected with the single screw 39 through a transmission belt to realize synchronous rotation.

When the double-screw extrusion device works, the driving motor drives the rotating shaft 5 to rotate, the rotating shaft 5 drives the first screw rod 3 to rotate, and the first screw rod 3 and the second screw rod 4 are driven by the driving belt 6, so that the second screw rod 4 rotates, and the rotation direction of the second screw rod 4 is the same as that of the first screw rod 3. And starting the heating section I12, the heat preservation section 16 and the cooling section to perform gradient heating, heat preservation and gradient cooling on the materials in the charging barrel 2. In the process, the forward helical blade a7 pushes the material to move to the right, and the forward helical blade b9 also pushes the material to move to the right. When the materials move to the reverse spiral blade a8 and the reverse spiral blade b28, the reverse spiral blade a8 and the reverse spiral blade b28 apply leftward thrust to the materials, so that the materials move leftward and retreat. However, since the outer diameter of the reverse spiral blade a8 is smaller than that of the forward spiral blade a7 and the outer diameter of the reverse spiral blade b28 is smaller than that of the forward spiral blade b9, and since the length of the reverse spiral blade a8 is shorter than that of the forward spiral blade a7 and the length of the reverse spiral blade b28 is shorter than that of the forward spiral blade b9 in this embodiment, the material as a whole still moves rightward. However, in the process of moving the material to the right, the material is pushed leftwards by the reverse helical blade a8, and at the moment, the material is also pushed rightwards by the forward helical blade a7 and the forward helical blade b9, so that the material is subjected to axial extrusion force, the material is compacted, and the compactness of the material is improved.

In the process that the material is pushed, the material needs to pass through the plurality of extrusion openings 36, and the material is further extruded when passing through the extrusion openings 36 through the limiting effect of the extrusion openings 36, so that the compactness of the material is further improved; and the driven shaft, the matching gear 33 and the push rod 34 are driven to rotate by the sector gear 32, so that the beating plate 35 is intermittently pushed out, and materials on the extrusion port 36 are beaten and compacted, so that the compactness of the materials is improved.

After the material is extruded and kneaded by the double-screw extruder, the material is discharged from the discharge port 11 into the feed pipe 38 of the single-screw extruder 39, the single-screw 39 drives the rotating rod 40 to rotate through the transmission belt in the rotating process, the rotating rod 40 drives the breaking rod 41 to rotate, the material passing through the feed pipe 38 is beaten and is driven to generate certain rotation, the material is thrown and broken, and therefore the compactness of the material in the single-screw extruder 39 is reduced, the material is loosened, and the material discharged from the single-screw extruder 39 is in a loose state.

Example 2

The present embodiment is different from embodiment 1 in that: this embodiment still includes the flue gas treatment process: and the flue gas treatment unit is used for timely discharging the vulcanized flue gas in the double-screw extruder. The flue gas processing unit is arranged on the charging barrel 2, and is mainly composed of a first gear 19, a second gear 20, a cam 21, a cylinder body, a piston 22, a second elastic part 25, an air inlet pipe 26 and an air outlet pipe 27, which are shown in the attached drawing 1. The first gear 19 is fixedly connected to the rotating shaft 5, the first gear 19 is engaged with the second gear 20, and the transmission ratio of the first gear 19 to the second gear 20 is less than 1, in this embodiment, the transmission ratio of the first gear 19 to the second gear 20 is 0.25. A cam 21 is coaxially and fixedly connected to the second gear 20. A cylinder body is fixedly arranged below the rotating shaft 5, a piston 22 is vertically and slidably connected in the cylinder body, the cylinder body is divided into an upper chamber 23 and a lower chamber 24 by the piston 22, the cam 21 is positioned in the upper chamber 23, the cam 21 abuts against the piston 22, a plurality of second elastic pieces 25 are fixedly connected to the top wall of the upper chamber 23, and the bottom ends of the second elastic pieces 25 are fixedly connected with the piston 22. In this embodiment, the number of the second elastic members 25 is two, and the second elastic members 25 are springs. A vent hole (not shown) is formed in a sidewall of the upper chamber 23 so that the interior of the upper chamber 23 is communicated with the external atmospheric pressure.

The lower chamber 24 is communicated with an air inlet pipe 26 and an air outlet pipe 27, the air inlet pipe 26 is fixedly provided with a first one-way valve for guiding air into the lower chamber 24, and the upper end of the air inlet pipe 26 is communicated with the left end of the charging barrel 2; a second one-way valve for guiding the gas out of the lower chamber 24 is fixedly mounted on the gas outlet pipe 27, and one end of the gas outlet pipe 27 far away from the cylinder body is connected with an environment-friendly device (i.e. a device for treating the flue gas).

The first gear 19 on the rotating shaft 5 is matched with the second gear 20 to drive the cam 21 to rotate, in the rotating process of the cam 21, the cam 21 pushes the piston 22 downwards, the piston 22 slides downwards, the volume of the lower chamber 24 is reduced, the internal pressure is increased, and the gas in the lower chamber 24 is discharged to an environment-friendly device (namely a device for harmlessly treating flue gas, which is the prior art and can be directly bought in the market, and is not described herein); when the cam 21 no longer applies a downward thrust to the piston 22, the piston 22 slides upward by the second elastic member 25, the volume of the lower chamber 24 increases, the internal pressure decreases, and the vulcanization generated in the cartridge 2 enters the lower chamber 24 through the intake pipe 26. Constantly repeat above-mentioned process, can be constantly inhale the vulcanization flue gas that produces in the material desulfurization process in the feed cylinder 2 to cavity 24 under in, carry to environment protection device department through outlet duct 27 again, avoid the vulcanization flue gas to cause the material to produce the bubble on the one hand, on the other hand also can avoid the vulcanization flue gas directly to discharge to the atmosphere, harm health and environment.

The foregoing is merely an example of the present invention and common general knowledge of known specific structures and features of the embodiments is not described herein in any greater detail. It should be noted that, for those skilled in the art, without departing from the structure of the present invention, several changes and modifications can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicability of the patent. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.

Claims

1. The method for controlling the extrusion compactness of the desulfurized rubber powder is characterized by comprising the following steps: the method comprises the following steps:

2. The method for controlling the extrusion compactness of the desulfurized rubber powder according to claim 1, characterized in that: in the first process, a plurality of reverse helical blades b are arranged on a second screw of the double-screw extruder at intervals, and the outer diameter of each reverse helical blade b is smaller than that of each forward helical blade b on the second screw.

3. The method for controlling the extrusion compactness of the desulfurized rubber powder according to claim 2, characterized in that: grooves are formed in the surfaces of the reverse helical blade a and the reverse helical blade b, so that the surfaces of the reverse helical blade a and the reverse helical blade b are uneven.

4. The method for controlling the extrusion compactness of the desulfurized rubber powder according to claim 1, characterized in that: in the second process, when the materials pass through the extrusion opening, the materials are beaten.

5. The method for controlling the extrusion compactness of the desulfurized rubber powder according to claim 1, characterized in that: further comprises a flue gas treatment process: and the flue gas treatment unit is used for timely discharging the vulcanized flue gas in the double-screw extruder.

6. The method for controlling the extrusion compactness of the desulfurized rubber powder according to any one of claims 1 to 5, characterized in that: the double-screw extruder comprises a driving motor, a rotating shaft, a charging barrel, a first screw and a second screw, wherein the first screw is provided with a forward helical blade a and a reverse helical blade a, the outer diameter of the reverse helical blade a is smaller than that of the forward helical blade a, the second screw is provided with a forward helical blade b and a reverse helical blade b, and the outer diameter of the reverse helical blade b is smaller than that of the forward helical blade b; a plurality of spacing blocks are arranged in the charging barrel, a first screw and a second screw penetrate through the spacing blocks and are rotationally connected with the spacing blocks, extrusion openings are formed in the spacing blocks, and striking units used for striking materials at the extrusion openings are arranged on the spacing blocks; the charging barrel is also provided with a smoke treatment unit.

7. The method for controlling the extrusion compactness of the desulfurized rubber powder according to claim 6, characterized in that: the beating unit comprises a movable cavity arranged in the spacer block, a second screw penetrates through the movable cavity and is provided with sector teeth, a driven shaft is rotatably connected in the movable cavity, a push rod and a matched gear meshed with the sector teeth are arranged on the driven shaft, the bottom of the movable cavity is slidably connected with a beating plate, the top of the beating plate is connected with a first elastic piece, and the first elastic piece is fixed in the movable cavity; the bottom of the striking plate can slide out of the movable cavity and enter the extrusion opening.

8. The method for controlling the extrusion compactness of the desulfurized rubber powder according to claim 7, characterized in that: the smoke treatment unit comprises a first gear fixedly connected to the rotating shaft, the first gear is meshed with a second gear, and the second gear is coaxially and fixedly connected with a cam; a cylinder body is fixedly arranged below the rotating shaft, a piston is vertically and slidably connected in the cylinder body, the cylinder body is divided into an upper chamber and a lower chamber by the piston, the cam is positioned in the upper chamber and abuts against the piston, the top wall of the upper chamber is fixedly connected with a plurality of second elastic pieces, and one end, far away from the top wall of the upper chamber, of each second elastic piece is fixedly connected with the piston; the lower cavity is communicated with an air inlet pipe and an air outlet pipe, a first one-way valve for guiding air into the lower cavity is fixedly mounted on the air inlet pipe, one end, away from the lower cavity, of the air inlet pipe is communicated with the charging barrel, the communicated position of the air inlet pipe and the charging barrel is located at the same side with the feeding hole, and a second one-way valve for guiding air out of the lower cavity is fixedly mounted on the air outlet pipe.

9. The method for controlling the extrusion compactness of the desulfurized rubber powder according to any one of claims 1 to 5, characterized in that: the single-screw extruder comprises a machine barrel, a single screw and a feeding pipe, wherein the feeding pipe is provided with a scattering unit.

10. The method for controlling the extrusion compactness of the desulfurized rubber powder according to claim 9, characterized in that: the scattering unit comprises a rotating rod connected to the feeding pipe in a horizontal rotating mode, a plurality of scattering rods are fixed on the rotating rod, and a transmission belt is connected between the rotating rod and the end portion of the single screw rod.