WO2014139065A1 - Screw rod of single screw extruder - Google Patents

Screw rod of single screw extruder Download PDF

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Publication number
WO2014139065A1
WO2014139065A1 PCT/CN2013/001114 CN2013001114W WO2014139065A1 WO 2014139065 A1 WO2014139065 A1 WO 2014139065A1 CN 2013001114 W CN2013001114 W CN 2013001114W WO 2014139065 A1 WO2014139065 A1 WO 2014139065A1
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WO
WIPO (PCT)
Prior art keywords
section
thread
main thread
mixing
bottom diameter
Prior art date
Application number
PCT/CN2013/001114
Other languages
French (fr)
Chinese (zh)
Inventor
罗庆青
叶镇波
陈诗煌
李意明
Original Assignee
广东达诚机械有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 广东达诚机械有限公司 filed Critical 广东达诚机械有限公司
Publication of WO2014139065A1 publication Critical patent/WO2014139065A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
    • B29C48/50—Details of extruders
    • B29C48/505—Screws
    • B29C48/52—Screws with an outer diameter varying along the longitudinal axis, e.g. for obtaining different thread clearance
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
    • B29C48/395—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders
    • B29C48/397—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders using a single screw
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
    • B29C48/50—Details of extruders
    • B29C48/505—Screws
    • B29C48/53—Screws having a varying channel depth, e.g. varying the diameter of the longitudinal screw trunk
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
    • B29C48/50—Details of extruders
    • B29C48/505—Screws
    • B29C48/64—Screws with two or more threads

Definitions

  • This invention relates to components of an extruder, and more particularly to a screw for a single screw extruder.
  • extruders are used to extrude plastic products (such as polyethylene terephthalate).
  • the equipment used is usually: a single-screw extruder without exhaust function, and a crystal drying equipment.
  • the plastic raw materials are crystallized and dried by a crystal drying equipment, and then sent to a single screw.
  • the extruder is subjected to extrusion processing; or a twin-screw extruder or a multi-screw extruder with a venting structure is used, and the plastic raw material can be directly fed into the twin-screw extruder or the multi-screw extruder for extrusion processing.
  • the technical problem to be solved by the present invention is to provide a screw of a single-screw extruder in which a plastic material extruded by a single-screw extruder using the screw has a high viscosity, and the obtained plastic product has less crystal dots and bubbles.
  • the technical solutions adopted are as follows:
  • the screw of the single-screw extruder includes a feeding section, a compression separation section and a metering section from front to back, and a main thread is arranged on the feeding section, and a main thread and a secondary thread are arranged on the compression separation section, and the measuring section
  • the main thread is provided with a mixing section between the compression separation section and the metering section, and a main thread and a secondary thread are arranged on the mixing section
  • the mixing section includes a plurality of mixing sections from front to back, wherein the The bottom diameter of the main thread on the odd-numbered mixed small sections gradually decreases from front to back, and the bottom diameter of the secondary thread gradually increases from front to back, and the main snail on the even-numbered mixed small section
  • the bottom diameter of the grain gradually increases from front to back, and the bottom diameter of the secondary thread gradually decreases from front to back.
  • the screw is sequentially a feed section, a compression separation section, a mixing section and a metering section from front to back.
  • the feed section the material enters the screw and melts, and the melt is formed and sent to the compression separation section;
  • the compression separation section has a melt channel and a solid groove, which can separate the melt in the material from the unmelted solid, thereby improving Melting efficiency, plasticizing the material initially;
  • the bottom and bottom threads of the mixing section alternately change (corrugated), and the material is compressed and relaxed alternately, and finally the material is completely plasticized and evenly mixed;
  • the material from the mixing section is melt homogenized and metered to the extruder die.
  • the screw has an aspect ratio of (30 - 37):1.
  • the mixing section has two melt channels, wherein a first melt channel is formed between the primary thread and the secondary thread, and a second melt channel is formed between the secondary thread and the primary thread.
  • a first melt channel is formed between the primary thread and the secondary thread
  • a second melt channel is formed between the secondary thread and the primary thread.
  • the bottom diameter of the front main thread of the latter mixing section is equal to the bottom diameter of the rear main thread of the previous mixing section
  • the bottom diameter of the front mixing auxiliary thread of the latter mixing section is equal to the rear mixing minor thread of the previous mixing section.
  • the bottom diameter allows the first melt channel and the second melt channel to smoothly transition adjacent the adjacent two mixing segments.
  • the outer diameter of the main thread on the odd-numbered mixing segments gradually decreases from front to back, and the outer diameter of the secondary thread gradually increases from front to back, and the outer diameter of the main thread on the even-numbered mixing segments is from front to back. Gradually increasing, the outer diameter of the secondary thread gradually decreases from front to back.
  • the material in the first melt groove can pass over the top of the secondary thread and overflow into the second melt groove; at the position where the secondary thread has a larger diameter, the second melt The material in the channel can pass over the top of the main thread and overflow into the first melt channel, thus, during the transport of the material (melt material) from front to back along the mixing section, the first melt channel and the second The melt channels can exchange materials with each other to make the material mix more evenly.
  • the mixing section comprises 3-6 mixing sections in order from front to back.
  • the mixing section includes a first mixing section, a second mixing section, a third mixing section and a fourth mixing section in sequence from front to back, wherein the bottom diameter and the outer diameter of the main thread on the first mixing section are from the front to the After the gradual decrease, the bottom diameter and the outer diameter of the main thread on the second mixing section gradually increase from front to back, and the bottom diameter and the outer diameter of the main thread on the third mixing section gradually decrease from front to back, the fourth mixing The bottom diameter and outer diameter of the main thread on the small section gradually increase from front to back, first The bottom diameter and the outer diameter of the auxiliary thread on the mixing section gradually increase from front to back, and the bottom diameter and the outer diameter of the secondary thread on the second mixing section gradually decrease from front to back, and the bottom diameter of the secondary thread on the third mixing section Both the outer diameter and the outer diameter gradually increase from front to back, and the bottom diameter and the outer diameter of the secondary thread on the fourth mixing small section gradually decrease
  • the bottom diameter of the main thread on the compression separation section gradually increases from front to back (generally, the bottom diameter of the main thread of the front end of the compression separation section is equal to the bottom diameter of the main thread on the feed section);
  • the compression separation section includes the front section of the compression separation section and compression In the rear section of the separation section, the bottom diameter of the secondary thread on the front section of the compression separation section gradually increases from front to back (usually the bottom diameter of the front end secondary thread of the front section of the compression separation section is equal to the bottom diameter of the main thread on the feed section), and the rear section of the compression separation section
  • the bottom diameter of the upper auxiliary thread gradually decreases from front to back (generally, the bottom diameter of the front end secondary thread of the rear section of the compression separation section is equal to the bottom diameter of the secondary thread at the rear end of the front section of the compression separation section), and the length of the front section of the compression separation section is compressed.
  • the total length of the separation section is from 3 to 7% (more preferably from 4 to 6%).
  • the bottom diameter of the main thread gradually increases from front to back, and the bottom diameter of the secondary thread gradually decreases from front to back, that is, the depth of the solid groove along the material conveying direction. Gradually decreasing, and the depth of the melt channel generally increases.
  • the outer diameter of the main thread on the compression separation section remains the same, and the outer diameter of the secondary thread remains the same.
  • the outer diameter of the secondary thread on the compression separation section is smaller than the outer diameter of the primary thread.
  • the width of the main thread of the above-mentioned feeding section and the diameter of the bottom thread are the same, and the width and the bottom diameter of the main thread of each part of the measuring section are also the same; the bottom diameter of the measuring section is larger than the feeding section.
  • the bottom diameter, the bottom diameter of the metering section and the bottom diameter of the feed section are determined according to the compression ratio required for extrusion.
  • the pitch of the main thread on the compression separation section and the mixing section is generally larger than the pitch of the main thread on the feeding section and the metering section;
  • the main thread on the compression separation section The pitch of the thread is generally the same as the pitch of the main thread on the mixing section;
  • the feed section includes the front section of the feed section and the rear section of the feed section, wherein the pitch of the main thread of each part of the front section of the feed section is uniform, after the feed section
  • the pitch of the main thread on the segment gradually increases from front to back, and the main thread pitch at the rear end of the rear section of the feed section is consistent with the main thread pitch of the compression separation section;
  • the above metering section includes the front section of the metering section and the rear section of the metering section, wherein the front section of the metering section
  • the pitch of the upper main thread gradually decreases from front to back, and the pitch of the main thread of each part on the rear section of the metering section is uniform, and
  • the invention adds a mixing section behind the compression separation section, and the bottom diameter of the main and auxiliary threads on the mixing section alternately changes, thereby realizing the alternating compression and relaxation of the material, and finally the material is completely plasticized and uniformly mixed. Therefore, the screw is used.
  • the material has a high viscosity (tested by a viscometer, the viscosity of the material drops less than 6% before and after processing), and the resulting plastic products have fewer crystal dots and bubbles, which is in line with industry standards.
  • Figure 1 is a schematic view showing the structure of a preferred embodiment of the present invention.
  • Fig. 2 is a schematic view showing the change of the bottom diameter and the outer diameter of the main thread on the screw shown in Fig. 1;
  • Fig. 3 is a schematic view showing the change of the bottom diameter and the outer diameter of the secondary thread on the compression separation section and the mixing section.
  • the screw of the single-screw extruder includes a feed section 1, a compression separation section 2, a mixing section 3 and a metering section 4 in order from the front to the rear, and a main thread is arranged on the feeding section 1.
  • the compression separation section 2 is provided with a main thread 5 and a secondary thread 6
  • the mixing section 3 is provided with a main thread 5 and a secondary thread 6
  • the metering section 4 is provided with a main thread 5.
  • the feed section 1 comprises a front section of the feed section 1 and a rear section of the feed section 1, wherein the pitch of the main threads 5 of the sections on the front section of the feed section 1 is uniform, and the main section of the feed section 1 is the main section.
  • the pitch of the thread 5 gradually increases from front to back, and the pitch of the main thread 5 at the rear end of the rear section of the feed section 1 coincides with the pitch of the main thread 5 of the compression separation section 2; the pitch of the main thread 5 of each part of the compression separation section 2 is Consistently, the pitch of the secondary threads 6 of the portions on the compression separation section 2 is also uniform; the pitch of the main threads 5 of the various sections on the mixing section 3 is uniform, and the pitch of the secondary threads 6 of the sections on the mixing section 3 is also uniform.
  • the pitch of the main thread 5 on the compression separation section 2 coincides with the pitch of the main thread 5 on the mixing section 3;
  • the metering section 4 includes the front section of the metering section 4 and the rear section of the metering section 4, wherein the main thread 5 of the front section of the metering section 4 The pitch gradually decreases from front to back, and the front end of the metering section 4
  • the pitch of the main thread 5 is the same as the pitch of the main thread 5 of the mixing section 4, and the pitch of the main thread 5 of each part of the rear section of the metering section 4 is uniform.
  • the thread width and the bottom diameter of the main thread 5 of each part of the feeding section 1 are identical, and the thread width and the bottom diameter of the main thread 5 of each part of the metering section 4 are also uniform; the bottom diameter of the metering section 4 is larger than The bottom diameter of the feed section 1, the bottom diameter of the metering section 4 and the bottom diameter of the feed section 1 are determined according to the compression ratio required for extrusion.
  • the bottom diameter of the main thread 5 on the compression separation section 2 gradually increases from front to back (the bottom diameter of the front end main thread 5 of the compression separation section 2 is equal to the bottom diameter of the main thread 5 on the feed section 1); the compression separation section 2 includes compression separation In the front section 21 of the section and the rear section 22 of the compression separation section, the bottom diameter of the secondary thread 6 on the front section 21 of the compression separation section gradually increases from front to back (the bottom diameter of the front end secondary thread 6 of the front section 21 of the compression separation section is equal to the main thread of the feeding section 1
  • the bottom diameter of the secondary thread 6 on the rear section 22 of the compression separation section gradually decreases from front to back (the bottom diameter of the front end secondary thread 6 of the rear section 22 of the compression separation section is equal to the rear secondary thread 6 of the front section 21 of the compression separation section
  • the bottom diameter of the compression separation section 21 in this embodiment accounts for about 5.6% of the total length of the compression separation section 2.
  • a melt groove 7 is formed between the main thread 5 and the auxiliary thread 6, and a solid groove 8 is formed between the auxiliary thread 6 and the main thread 5; the depth of the solid groove 8 along the material conveying direction Gradually decreasing, and the depth of the melt channel 7 is gradually increased as a whole.
  • the outer diameter of the main thread 5 on the compression separation section 2 is kept the same, and the outer diameter of the secondary thread 6 on the compression separation section 2 is also kept uniform, and the outer diameter of the secondary thread 6 on the compression separation section 2 is smaller than the outer diameter of the main thread 5.
  • the mixing section 3 includes a plurality of (for example, 3-6) mixing sections in order from the front to the rear, wherein the bottom diameter of the main thread 5 on the odd-numbered mixing small sections gradually decreases from front to back, and the bottom diameter of the secondary thread 6 gradually increases from front to back.
  • the outer diameter of the main thread 5 on the even-numbered mixing small sections gradually increases from front to back, and the bottom diameter of the secondary thread 6 gradually decreases from front to back; the outer diameter of the main thread 5 on the odd-numbered mixing small sections is from front to back
  • the outer diameter of the secondary thread 6 gradually increases from front to back, and the outer diameter of the main thread 5 on the even number of mixing small sections gradually increases from front to back, and the outer diameter of the secondary thread 6 gradually decreases from front to back.
  • the mixing section 3 has two melt channels, wherein a first melt channel 9 is formed between the main thread 5 and the secondary thread 6, and a second melt channel 10 is formed between the secondary thread 6 and the main thread 5;
  • the bottom diameter of the front end main thread 5 of the mixing section is equal to the bottom diameter of the rear main thread 5 of the previous mixing section, and the bottom diameter of the front side auxiliary thread 6 of the latter mixing section.
  • the bottom diameter of the rear mixing sub-thread 6 of the previous mixing section is such that the first melt channel 9 and the second melt channel 10 are smoothly transitioned at the abutment of the adjacent two mixing sections.
  • the mixing section 3 includes a first mixing section 31, a second mixing section 32, a third mixing section 33 and a fourth mixing section 34 in order from the front to the rear, and the bottom diameter of the main thread 5 on the first mixing section 31
  • the outer diameter gradually decreases from front to back, and the bottom diameter and the outer diameter of the main thread 5 on the second mixing section 32 gradually increase from front to back, and the bottom diameter and the outer diameter of the main thread 5 on the third mixing section 33 are all from the front.
  • the bottom diameter and the outer diameter of the main thread 5 on the fourth mixing section 34 gradually increase from front to back, and the bottom diameter and the outer diameter of the auxiliary thread 6 on the first mixing section 31 gradually increase from front to back.
  • the bottom diameter and the outer diameter of the secondary thread 6 on the second mixing section 32 are gradually decreased from front to back, and the bottom diameter and the outer diameter of the secondary thread 6 on the third mixing section 33 are gradually increased from front to back, and fourth.
  • the bottom and outer diameters of the secondary threads 6 on the mixing section 34 are gradually reduced from front to back.
  • the screw is further described below using a set of specific design parameters (refer to FIG. 2 and FIG. 3, and curves 11 and 13 in FIG. 2 respectively show the variation of the bottom diameter and the outer diameter of the main thread 5 on the screw, and curve 12 in FIG. 14 shows the change of the bottom diameter and the outer diameter of the secondary thread 6 on the compression separation section 2 and the mixing section 3 respectively:
  • the length to diameter ratio of the screw is 34.2:1.
  • the length of the feed section 1 is 9Ds (Ds represents the outer diameter of the screw, that is, the outer diameter of the main thread 5 on the feed section 1), the width of the main thread 5 is 0.1Ds, and the bottom diameter of the main thread 5 is 0.65Ds;
  • the length of the front section of the feed section 1 is 7Ds, the length of the rear section of the feed section 1 is 2Ds, the pitch of the main thread 5 on the front section of the feed section 1 is IDs, and the pitch of the main thread 5 at the front end of the feed section 1 is IDs.
  • the pitch of the main thread 5 at the rear end of the rear section of the feed section 1 is 1.2 Ds.
  • the length of the compression separation section 2 is 10.7Ds, the length of the front section 21 of the compression separation section is 0.6Ds, and the length of the rear section 22 of the compression separation section is lO. lDs; the pitch of the main thread 5 and the secondary thread 6 on the compression separation section 2 are both For 1.2Ds, the distance between the starting end of the secondary thread 6 and the main thread 5 on the compression separation section 2 is 0.32Ds, and the bottom diameter of the 2 main thread 5 on the compression separation section is gradually increased from 0.65Ds to 0.94Ds, and the compression separation section front section 21 The bottom diameter of the upper secondary thread 6 is gradually increased from 0.65DS to 0.88Ds, and the bottom diameter of the secondary thread 6 on the rear section 22 of the compression separation section is gradually reduced from 0.88DS to 0.7Ds.
  • the length of the mixing section 3 is l lDs, and the lengths of the first mixing section 31, the second mixing section 32, the third mixing section 33 and the fourth mixing section 34 are respectively 3.7 Ds, 2.4 Ds, 2.4 Ds, 2.5Ds; the bottom diameter of the main thread 5 on the first mixing section 31 is gradually reduced from 0.94Ds to 0.79DS (the bottom diameter of the starting end of the main thread 5 on the first mixing section 31 and the end of the main thread 5 on the compression separation section 2) The bottom diameter is uniform), the bottom diameter of the main thread 5 on the second mixing section 32 is gradually increased from 0.79 Ds to 0.91 Ds, and the bottom diameter of the main thread 5 on the third mixing section 33 is gradually reduced from 0.91 Ds to 0.8 Ds, The bottom diameter of the main thread 5 on the four mixing section 34 is gradually increased from 0.8 Ds to 0.9 Ds (the bottom diameter of the end of the main thread 5 on the fourth mixing section 34 coincides with the bottom diameter of the main thread 5 on the metering section 4); The bottom diameter of the
  • the length of the metering section 4 is 3.5Ds, the width of the main thread 5 is 0.1Ds, the diameter of the main thread 5 is 0.9Ds, the length of the front section of the metering section 4 is 2 Ds, and the length of the rear section of the metering section 4 is 1.5 Ds.
  • the pitch of the main thread 5 at the front end of the front section of the metering section 4 is 1.2 Ds, the pitch of the main thread 5 at the rear end of the front section of the metering section 4 is IDs, and the pitch of the main thread 5 on the rear section of the metering section 4 is lDs.
  • the compression separation section 2 has a melt channel 7 and a solid groove 8, and as the material is transported, the solid material in the solid channel 8 gradually melts into a melt and enters the melt channel 7.
  • the compression separation section 2 is capable of separating the melt in the material from the unmelted solids, improving the melting efficiency, and initially plasticizing the material.
  • the bottom and bottom threads of the mixing section 3 alternately change (corrugated), which alternates the compression and relaxation of the material, and finally completely plasticizes the material from the compression separation section 2. And mix well.
  • the material in the first melt channel 9 can pass over the top of the secondary thread 6 and overflow into the second melt channel 10;
  • the material in the second melt channel 10 can pass over the top of the main thread 5 and overflow into the first melt channel 9, thus, in the material (melt material) along the mixing section 3 from front to back During the conveying process, the first melt channel 9 and the second melt channel 10 can exchange materials with each other to make the material mixing more uniform.
  • Metering section 4 melts the material from mixing section 3 and homogenizes it to the extruder die.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)

Abstract

A screw rod of a single screw extruder comprises a feeding section (1), a compression separation section (2), and a metering section (4) which are sequentially arranged from front to back. The feeding section (1) is provided with a main thread (5), the compression separation section (2) is provided with a main thread (5) and an auxiliary thread (6), and the metering section (4) is provided with a main thread (5). A mixed section (3) is arranged between the compression separation section (2) and the metering section (4), is provided with main threads (5) and auxiliary threads (6), and comprises a plurality of mixed subsections which are sequentially arranged from front to back. The bottom diameters of the main threads on the odd numbers of mixed subsections gradually decrease from front to back, and the bottom diameters of the auxiliary threads on the odd numbers of mixed subsections gradually increase. The bottom diameters of the main threads on the even numbers of mixed subsections gradually increase from front to back, and the bottom diameters of the auxiliary threads on the even numbers of mixed subsections gradually decrease from front to back. The bottom diameters of the main and auxiliary threads on the mixed sections change alternately, so that materials can be alternately compressed and released, and completely plasticized and uniformly mixed. Therefore, the plastic material extruded by the single screw extruder with the screw rod has high viscosity, and a plastic product produced by the extruder has few crystal points and bubbles.

Description

单螺杆挤出机的螺杆  Single screw extruder screw
技术领域 Technical field
本发明涉及挤出机的零部件， 具体涉及一种单螺杆挤出机的螺 杆。  This invention relates to components of an extruder, and more particularly to a screw for a single screw extruder.
背景技术 Background technique
目前， 采用挤出机挤出加工塑料制品（如聚对苯二甲酸乙二醇酯 Currently, extruders are used to extrude plastic products (such as polyethylene terephthalate).
(PET) 制品） 的过程中， 所用设备通常为： 采用不带排气功能的单 螺杆挤出机， 并配套使用结晶干燥设备， 塑料原料经结晶干燥设备作 结晶干燥处理后， 送入单螺杆挤出机进行挤出加工； 或者采用带排气 结构的双螺杆挤出机或多螺杆挤出机，塑料原料可直接送入该双螺杆 挤出机或多螺杆挤出机进行挤出加工。 In the process of (PET) products, the equipment used is usually: a single-screw extruder without exhaust function, and a crystal drying equipment. The plastic raw materials are crystallized and dried by a crystal drying equipment, and then sent to a single screw. The extruder is subjected to extrusion processing; or a twin-screw extruder or a multi-screw extruder with a venting structure is used, and the plastic raw material can be directly fed into the twin-screw extruder or the multi-screw extruder for extrusion processing.
采用不带排气功能的单螺杆挤出机进行挤出加工时，经常会出现 以下几个问题： 1、熔体混合不够均匀， 以致制得的塑料制品（如 PET 制品） 晶点和气泡较多； 2、 为了实现较好的塑化效果， 要求螺杆具 有较大的压缩比， 这会导致塑料物料温度升高较大， 以致挤出的塑料 物料粘度低， 制得的塑料制品颜色偏黄； 3、 挤出加工过程中能耗高。 发明内容  When using a single-screw extruder without exhaust function for extrusion processing, the following problems often occur: 1. The melt mixing is not uniform enough, so that the prepared plastic products (such as PET products) have crystal points and bubbles. 2. In order to achieve a better plasticizing effect, the screw is required to have a large compression ratio, which causes the temperature of the plastic material to rise so much that the extruded plastic material has a low viscosity, and the obtained plastic product has a yellowish color. 3, high energy consumption during extrusion processing. Summary of the invention
本发明所要解决的技术问题是提供一种单螺杆挤出机的螺杆，采 用这种螺杆的单螺杆挤出机挤出的塑料物料粘度较高，并且制得的塑 料制品晶点和气泡少。 采用的技术方案如下：  The technical problem to be solved by the present invention is to provide a screw of a single-screw extruder in which a plastic material extruded by a single-screw extruder using the screw has a high viscosity, and the obtained plastic product has less crystal dots and bubbles. The technical solutions adopted are as follows:
一种单螺杆挤出机的螺杆， 自前至后依次包括进料段、压缩分离 段和计量段， 进料段上设有主螺纹， 压縮分离段上设有主螺纹和副螺 纹， 计量段上设有主螺纹， 其特征是： 所述压缩分离段与计量段之间 设有混合段， 混合段上设有主螺纹和副螺纹， 混合段自前至后依次包 括多个混合小段，其中第奇数个混合小段上主螺纹的底径自前至后逐 渐减小、副螺纹的底径自前至后逐渐增大， 第偶数个混合小段上主螺 纹的底径自前至后逐渐增大、 副螺纹的底径自前至后逐渐减小。 The screw of the single-screw extruder includes a feeding section, a compression separation section and a metering section from front to back, and a main thread is arranged on the feeding section, and a main thread and a secondary thread are arranged on the compression separation section, and the measuring section The main thread is provided with a mixing section between the compression separation section and the metering section, and a main thread and a secondary thread are arranged on the mixing section, and the mixing section includes a plurality of mixing sections from front to back, wherein the The bottom diameter of the main thread on the odd-numbered mixed small sections gradually decreases from front to back, and the bottom diameter of the secondary thread gradually increases from front to back, and the main snail on the even-numbered mixed small section The bottom diameter of the grain gradually increases from front to back, and the bottom diameter of the secondary thread gradually decreases from front to back.
上述螺杆自前至后依次为进料段、压缩分离段、混合段和计量段。 在进料段， 物料进入螺杆并熔化， 形成熔体后输送给压縮分离段； 压 缩分离段具有熔体螺槽和固体螺槽，能够将物料中的熔体与未熔融的 固体分开， 提高熔融效率， 初步对物料进行塑化； 混合段上主副螺纹 底径交替发生变化（呈波纹状）， 实现物料的压缩、 放松的交替发生， 最终使物料完全塑化并混合均匀；计量段使来自混合段的物料熔融均 化并定量输送至挤出机模头。  The screw is sequentially a feed section, a compression separation section, a mixing section and a metering section from front to back. In the feed section, the material enters the screw and melts, and the melt is formed and sent to the compression separation section; the compression separation section has a melt channel and a solid groove, which can separate the melt in the material from the unmelted solid, thereby improving Melting efficiency, plasticizing the material initially; the bottom and bottom threads of the mixing section alternately change (corrugated), and the material is compressed and relaxed alternately, and finally the material is completely plasticized and evenly mixed; The material from the mixing section is melt homogenized and metered to the extruder die.
优选所述螺杆的长径比为 （30— 37) :1。  Preferably, the screw has an aspect ratio of (30 - 37):1.
上述混合段具有两个熔体螺槽，其中主螺纹与副螺纹之间形成第 一熔体螺槽， 副螺纹与主螺纹之间形成第二熔体螺槽。通常， 上述混 合段中，后一混合小段前端主螺纹的底径等于前一混合小段后端主螺 纹的底径，后一混合小段前端副螺纹的底径等于前一混合小段后端副 螺纹的底径，使第一熔体螺槽和第二熔体螺槽在相邻两混合小段的邻 接处平稳过渡。  The mixing section has two melt channels, wherein a first melt channel is formed between the primary thread and the secondary thread, and a second melt channel is formed between the secondary thread and the primary thread. Generally, in the mixing section, the bottom diameter of the front main thread of the latter mixing section is equal to the bottom diameter of the rear main thread of the previous mixing section, and the bottom diameter of the front mixing auxiliary thread of the latter mixing section is equal to the rear mixing minor thread of the previous mixing section. The bottom diameter allows the first melt channel and the second melt channel to smoothly transition adjacent the adjacent two mixing segments.
优选上述混合段上，第奇数个混合小段上主螺紋的外径自前至后 逐渐减小、副螺纹的外径自前至后逐渐增大， 第偶数个混合小段上主 螺纹的外径自前至后逐渐增大、副螺纹的外径自前至后逐渐减小。在 主螺紋底径较大的位置，第一熔体螺槽中的物料能够越过副螺纹顶部 并溢流到第二熔体螺槽中； 在副螺纹底径较大的位置， 第二熔体螺槽 中的物料能够越过主螺纹顶部并溢流到第一熔体螺槽中， 这样， 在物 料（熔融物料）沿混合段自前至后输送的过程中， 第一熔体螺槽与第 二熔体螺槽相互之间能够进行物料交流， 使物料混合更加均匀。  Preferably, on the mixing section, the outer diameter of the main thread on the odd-numbered mixing segments gradually decreases from front to back, and the outer diameter of the secondary thread gradually increases from front to back, and the outer diameter of the main thread on the even-numbered mixing segments is from front to back. Gradually increasing, the outer diameter of the secondary thread gradually decreases from front to back. At a position where the diameter of the main thread has a large diameter, the material in the first melt groove can pass over the top of the secondary thread and overflow into the second melt groove; at the position where the secondary thread has a larger diameter, the second melt The material in the channel can pass over the top of the main thread and overflow into the first melt channel, thus, during the transport of the material (melt material) from front to back along the mixing section, the first melt channel and the second The melt channels can exchange materials with each other to make the material mix more evenly.
优选上述混合段自前至后依次包括 3— 6个混合小段。 一种具体 方案中，上述混合段自前至后依次包括第一混合小段、第二混合小段、 第三混合小段和第四混合小段，第一混合小段上主螺纹的底径和外径 均自前至后逐渐减小，第二混合小段上主螺纹的底径和外径均自前至 后逐渐增大，第三混合小段上主螺纹的底径和外径均自前至后逐渐减 小， 第四混合小段上主螺纹的底径和外径均自前至后逐渐增大， 第一 混合小段上副螺纹的底径和外径均自前至后逐渐增大，第二混合小段 上副螺纹的底径和外径均自前至后逐渐减小，第三混合小段上副螺紋 的底径和外径均自前至后逐渐增大，第四混合小段上副螺纹的底径和 外径均自前至后逐渐减小。 Preferably, the mixing section comprises 3-6 mixing sections in order from front to back. In a specific solution, the mixing section includes a first mixing section, a second mixing section, a third mixing section and a fourth mixing section in sequence from front to back, wherein the bottom diameter and the outer diameter of the main thread on the first mixing section are from the front to the After the gradual decrease, the bottom diameter and the outer diameter of the main thread on the second mixing section gradually increase from front to back, and the bottom diameter and the outer diameter of the main thread on the third mixing section gradually decrease from front to back, the fourth mixing The bottom diameter and outer diameter of the main thread on the small section gradually increase from front to back, first The bottom diameter and the outer diameter of the auxiliary thread on the mixing section gradually increase from front to back, and the bottom diameter and the outer diameter of the secondary thread on the second mixing section gradually decrease from front to back, and the bottom diameter of the secondary thread on the third mixing section Both the outer diameter and the outer diameter gradually increase from front to back, and the bottom diameter and the outer diameter of the secondary thread on the fourth mixing small section gradually decrease from front to back.
优选上述压缩分离段上主螺纹的底径自前至后逐渐增大（通常压 缩分离段前端主螺纹的底径等于进料段上主螺纹的底径）； 压缩分离 段包括压缩分离段前段和压缩分离段后段，压缩分离段前段上副螺纹 的底径自前至后逐渐增大（通常压缩分离段前段前端副螺纹的底径等 于进料段上主螺纹的底径）， 压缩分离段后段上副螺纹的底径自前至 后逐渐减小（通常压缩分离段后段前端副螺纹的底径等于压缩分离段 前段后端的副螺纹的底径）， 所述压缩分离段前段的长度占压縮分离 段总长度的 3— 7 % (更优选 4一 6% )。 这样， 在压缩分离段上， 主螺 纹的底径自前至后逐渐增大，而副螺纹的底径总体上自前至后逐渐减 小， 也就是说， 沿着物料输送方向， 固体螺槽的深度逐渐减小， 而熔 体螺槽的深度总体上逐渐增大。通常压缩分离段上主螺纹的外径保持 一致、副螺纹的外径也保持一致。优选压缩分离段上副螺纹的外径小 于主螺纹的外径， 随着物料的输送， 固体螺槽中的固体物料逐渐熔融 变成熔体， 并进入到熔体螺槽中。  Preferably, the bottom diameter of the main thread on the compression separation section gradually increases from front to back (generally, the bottom diameter of the main thread of the front end of the compression separation section is equal to the bottom diameter of the main thread on the feed section); the compression separation section includes the front section of the compression separation section and compression In the rear section of the separation section, the bottom diameter of the secondary thread on the front section of the compression separation section gradually increases from front to back (usually the bottom diameter of the front end secondary thread of the front section of the compression separation section is equal to the bottom diameter of the main thread on the feed section), and the rear section of the compression separation section The bottom diameter of the upper auxiliary thread gradually decreases from front to back (generally, the bottom diameter of the front end secondary thread of the rear section of the compression separation section is equal to the bottom diameter of the secondary thread at the rear end of the front section of the compression separation section), and the length of the front section of the compression separation section is compressed. The total length of the separation section is from 3 to 7% (more preferably from 4 to 6%). Thus, on the compression separation section, the bottom diameter of the main thread gradually increases from front to back, and the bottom diameter of the secondary thread gradually decreases from front to back, that is, the depth of the solid groove along the material conveying direction. Gradually decreasing, and the depth of the melt channel generally increases. Usually, the outer diameter of the main thread on the compression separation section remains the same, and the outer diameter of the secondary thread remains the same. Preferably, the outer diameter of the secondary thread on the compression separation section is smaller than the outer diameter of the primary thread. As the material is transported, the solid material in the solid groove gradually melts into a melt and enters the melt channel.
通常上述进料段上各部分的主螺纹的螺棱宽度和底径是一致的， 计量段上各部分的主螺紋的螺棱宽度和底径也是一致的；计量段的底 径大于进料段的底径，计量段的底径和进料段的底径根据挤出所需压 缩比确定。  Generally, the width of the main thread of the above-mentioned feeding section and the diameter of the bottom thread are the same, and the width and the bottom diameter of the main thread of each part of the measuring section are also the same; the bottom diameter of the measuring section is larger than the feeding section The bottom diameter, the bottom diameter of the metering section and the bottom diameter of the feed section are determined according to the compression ratio required for extrusion.
具体设计中， 由于压缩分离段和混合段上增设有副螺纹， 因此压 缩分离段及混合段上主螺纹的螺距通常比进料段及计量段上主螺纹 的螺距大；压缩分离段上主螺纹的螺距通常与混合段上主螺纹的螺距 一致； 上述进料段包括进料段前段和进料段后段， 其中进料段前段上 各部分的主螺纹的螺距是一致的，进料段后段上主螺纹的螺距自前至 后逐渐增大，进料段后段后端的主螺纹螺距与压缩分离段的主螺纹螺 距一致； 上述计量段包括计量段前段和计量段后段， 其中计量段前段 上主螺纹的螺距自前至后逐渐减小，计量段后段上各部分的主螺纹的 螺距是一致的，计量段前段前端的主螺纹螺距与混合段的主螺纹螺距 一致。 In the specific design, since the secondary thread is added to the compression separation section and the mixing section, the pitch of the main thread on the compression separation section and the mixing section is generally larger than the pitch of the main thread on the feeding section and the metering section; the main thread on the compression separation section The pitch of the thread is generally the same as the pitch of the main thread on the mixing section; the feed section includes the front section of the feed section and the rear section of the feed section, wherein the pitch of the main thread of each part of the front section of the feed section is uniform, after the feed section The pitch of the main thread on the segment gradually increases from front to back, and the main thread pitch at the rear end of the rear section of the feed section is consistent with the main thread pitch of the compression separation section; the above metering section includes the front section of the metering section and the rear section of the metering section, wherein the front section of the metering section The pitch of the upper main thread gradually decreases from front to back, and the pitch of the main thread of each part on the rear section of the metering section is uniform, and the main thread pitch of the front end of the metering section is the same as the main thread pitch of the mixing section.
本发明通过在压缩分离段后面增设混合段，混合段上主副螺纹底 径交替发生变化， 实现物料的压缩、 放松的交替发生， 最终使物料完 全塑化并混合均匀， 因此， 采用这种螺杆的单螺杆挤出机挤出的塑料 The invention adds a mixing section behind the compression separation section, and the bottom diameter of the main and auxiliary threads on the mixing section alternately changes, thereby realizing the alternating compression and relaxation of the material, and finally the material is completely plasticized and uniformly mixed. Therefore, the screw is used. Single screw extruder extruded plastic
(如 PET)物料粘度较高（通过粘度测量仪的测试， 加工前后物料的 粘度下降小于 6%)， 并且制得的塑料制品晶点和气泡少，符合行业标 准。 (eg PET) The material has a high viscosity (tested by a viscometer, the viscosity of the material drops less than 6% before and after processing), and the resulting plastic products have fewer crystal dots and bubbles, which is in line with industry standards.
附图说明 DRAWINGS
图 1是本发明优选实施例的结构示意图；  Figure 1 is a schematic view showing the structure of a preferred embodiment of the present invention;
图 2是图 1所示螺杆上主螺纹的底径及外径的变化示意图； 图 3 是压缩分离段及混合段上副螺纹的底径及外径的变化示意 图。  Fig. 2 is a schematic view showing the change of the bottom diameter and the outer diameter of the main thread on the screw shown in Fig. 1; Fig. 3 is a schematic view showing the change of the bottom diameter and the outer diameter of the secondary thread on the compression separation section and the mixing section.
具体实施方式 detailed description
如图 1一图 3所示， 这种单螺杆挤出机的螺杆自前至后依次包括 进料段 1、 压缩分离段 2、 混合段 3和计量段 4， 进料段 1上设有主 螺纹 5， 压缩分离段 2上设有主螺纹 5和副螺纹 6， 混合段 3上设有 主螺纹 5和副螺纹 6， 计量段 4上设有主螺纹 5。 本实施例中， 进料 段 1包括进料段 1前段和进料段 1后段，其中进料段 1前段上各部分 的主螺纹 5的螺距是一致的，进料段 1后段上主螺纹 5的螺距自前至 后逐渐增大，进料段 1后段后端的主螺纹 5螺距与压缩分离段 2的主 螺纹 5螺距一致;压縮分离段 2上各部分的主螺纹 5的螺距是一致的， 压缩分离段 2上各部分的副螺纹 6的螺距也是一致的；混合段 3上各 部分的主螺纹 5的螺距是一致的，混合段 3上各部分的副螺纹 6的螺 距也是一致的；压縮分离段 2上主螺纹 5的螺距与混合段 3上主螺纹 5的螺距一致； 计量段 4包括计量段 4前段和计量段 4后段， 其中计 量段 4前段上主螺纹 5的螺距自前至后逐渐减小，计量段 4前段前端 的主螺纹 5螺距与混合段 4的主螺纹 5螺距一致，计量段 4后段上各 部分的主螺纹 5的螺距是一致的。 As shown in FIG. 1 to FIG. 3, the screw of the single-screw extruder includes a feed section 1, a compression separation section 2, a mixing section 3 and a metering section 4 in order from the front to the rear, and a main thread is arranged on the feeding section 1. 5, the compression separation section 2 is provided with a main thread 5 and a secondary thread 6, the mixing section 3 is provided with a main thread 5 and a secondary thread 6, and the metering section 4 is provided with a main thread 5. In the present embodiment, the feed section 1 comprises a front section of the feed section 1 and a rear section of the feed section 1, wherein the pitch of the main threads 5 of the sections on the front section of the feed section 1 is uniform, and the main section of the feed section 1 is the main section. The pitch of the thread 5 gradually increases from front to back, and the pitch of the main thread 5 at the rear end of the rear section of the feed section 1 coincides with the pitch of the main thread 5 of the compression separation section 2; the pitch of the main thread 5 of each part of the compression separation section 2 is Consistently, the pitch of the secondary threads 6 of the portions on the compression separation section 2 is also uniform; the pitch of the main threads 5 of the various sections on the mixing section 3 is uniform, and the pitch of the secondary threads 6 of the sections on the mixing section 3 is also uniform. The pitch of the main thread 5 on the compression separation section 2 coincides with the pitch of the main thread 5 on the mixing section 3; the metering section 4 includes the front section of the metering section 4 and the rear section of the metering section 4, wherein the main thread 5 of the front section of the metering section 4 The pitch gradually decreases from front to back, and the front end of the metering section 4 The pitch of the main thread 5 is the same as the pitch of the main thread 5 of the mixing section 4, and the pitch of the main thread 5 of each part of the rear section of the metering section 4 is uniform.
进料段 1上各部分的主螺纹 5的螺棱宽度和底径是一致的，计量 段 4上各部分的主螺纹 5的螺棱宽度和底径也是一致的；计量段 4的 底径大于进料段 1的底径，计量段 4的底径和进料段 1的底径根据挤 出所需压缩比确定。  The thread width and the bottom diameter of the main thread 5 of each part of the feeding section 1 are identical, and the thread width and the bottom diameter of the main thread 5 of each part of the metering section 4 are also uniform; the bottom diameter of the metering section 4 is larger than The bottom diameter of the feed section 1, the bottom diameter of the metering section 4 and the bottom diameter of the feed section 1 are determined according to the compression ratio required for extrusion.
压缩分离段 2上主螺纹 5的底径自前至后逐渐增大（压缩分离段 2前端主螺纹 5的底径等于进料段 1上主螺紋 5的底径）； 压缩分离 段 2包括压缩分离段前段 21和压缩分离段后段 22， 压缩分离段前段 21上副螺纹 6的底径自前至后逐渐增大（压缩分离段前段 21前端副 螺纹 6的底径等于进料段 1上主螺纹 5的底径）， 压缩分离段后段 22 上副螺纹 6的底径自前至后逐渐减小 （压缩分离段后段 22前端副螺 纹 6的底径等于压缩分离段前段 21后端副螺纹 6的底径），本实施例 中压缩分离段前段 21的长度约占压缩分离段 2总长度的 5.6%。在压 缩分离段 2上， 主螺纹 5与副螺纹 6之间形成熔体螺槽 7， 副螺纹 6 与主螺纹 5之间形成固体螺槽 8; 沿着物料输送方向， 固体螺槽 8的 深度逐渐减小， 而熔体螺槽 7的深度总体上逐渐增大。 压缩分离段 2 上主螺纹 5的外径保持一致，压缩分离段 2上副螺纹 6的外径也保持 一致， 压缩分离段 2上副螺纹 6的外径小于主螺纹 5的外径。  The bottom diameter of the main thread 5 on the compression separation section 2 gradually increases from front to back (the bottom diameter of the front end main thread 5 of the compression separation section 2 is equal to the bottom diameter of the main thread 5 on the feed section 1); the compression separation section 2 includes compression separation In the front section 21 of the section and the rear section 22 of the compression separation section, the bottom diameter of the secondary thread 6 on the front section 21 of the compression separation section gradually increases from front to back (the bottom diameter of the front end secondary thread 6 of the front section 21 of the compression separation section is equal to the main thread of the feeding section 1 The bottom diameter of 5), the bottom diameter of the secondary thread 6 on the rear section 22 of the compression separation section gradually decreases from front to back (the bottom diameter of the front end secondary thread 6 of the rear section 22 of the compression separation section is equal to the rear secondary thread 6 of the front section 21 of the compression separation section The bottom diameter of the compression separation section 21 in this embodiment accounts for about 5.6% of the total length of the compression separation section 2. On the compression separation section 2, a melt groove 7 is formed between the main thread 5 and the auxiliary thread 6, and a solid groove 8 is formed between the auxiliary thread 6 and the main thread 5; the depth of the solid groove 8 along the material conveying direction Gradually decreasing, and the depth of the melt channel 7 is gradually increased as a whole. The outer diameter of the main thread 5 on the compression separation section 2 is kept the same, and the outer diameter of the secondary thread 6 on the compression separation section 2 is also kept uniform, and the outer diameter of the secondary thread 6 on the compression separation section 2 is smaller than the outer diameter of the main thread 5.
混合段 3 自前至后依次包括多个 （如 3— 6个） 混合小段， 其中 第奇数个混合小段上主螺纹 5的底径自前至后逐渐减小、副螺纹 6的 底径自前至后逐渐增大，第偶数个混合小段上主螺纹 5的底径自前至 后逐渐增大、副螺纹 6的底径自前至后逐渐减小； 第奇数个混合小段 上主螺纹 5的外径自前至后逐渐减小、副螺纹 6的外径自前至后逐渐 增大， 第偶数个混合小段上主螺纹 5的外径自前至后逐渐增大、副螺 纹 6的外径自前至后逐渐减小。混合段 3具有两个熔体螺槽， 其中主 螺纹 5与副螺纹 6之间形成第一熔体螺槽 9， 副螺纹 6与主螺纹 5之 间形成第二熔体螺槽 10; 后一混合小段前端主螺纹 5 的底径等于前 一混合小段后端主螺纹 5的底径，后一混合小段前端副螺纹 6的底径 等于前一混合小段后端副螺纹 6的底径，使第一熔体螺槽 9和第二熔 体螺槽 10在相邻两混合小段的邻接处均平稳过渡。 本实施例中， 混 合段 3 自前至后依次包括第一混合小段 31、 第二混合小段 32、 第三 混合小段 33和第四混合小段 34， 第一混合小段 31上主螺纹 5的底 径和外径均自前至后逐渐减小， 第二混合小段 32上主螺纹 5的底径 和外径均自前至后逐渐增大， 第三混合小段 33上主螺纹 5的底径和 外径均自前至后逐渐减小， 第四混合小段 34上主螺纹 5的底径和外 径均自前至后逐渐增大， 第一混合小段 31上副螺纹 6的底径和外径 均自前至后逐渐增大， 第二混合小段 32上副螺纹 6的底径和外径均 自前至后逐渐减小， 第三混合小段 33上副螺纹 6的底径和外径均自 前至后逐渐增大， 第四混合小段 34上副螺纹 6的底径和外径均自前 至后逐渐减小。 The mixing section 3 includes a plurality of (for example, 3-6) mixing sections in order from the front to the rear, wherein the bottom diameter of the main thread 5 on the odd-numbered mixing small sections gradually decreases from front to back, and the bottom diameter of the secondary thread 6 gradually increases from front to back. Increasing, the bottom diameter of the main thread 5 on the even-numbered mixing small sections gradually increases from front to back, and the bottom diameter of the secondary thread 6 gradually decreases from front to back; the outer diameter of the main thread 5 on the odd-numbered mixing small sections is from front to back Gradually, the outer diameter of the secondary thread 6 gradually increases from front to back, and the outer diameter of the main thread 5 on the even number of mixing small sections gradually increases from front to back, and the outer diameter of the secondary thread 6 gradually decreases from front to back. The mixing section 3 has two melt channels, wherein a first melt channel 9 is formed between the main thread 5 and the secondary thread 6, and a second melt channel 10 is formed between the secondary thread 6 and the main thread 5; The bottom diameter of the front end main thread 5 of the mixing section is equal to the bottom diameter of the rear main thread 5 of the previous mixing section, and the bottom diameter of the front side auxiliary thread 6 of the latter mixing section The bottom diameter of the rear mixing sub-thread 6 of the previous mixing section is such that the first melt channel 9 and the second melt channel 10 are smoothly transitioned at the abutment of the adjacent two mixing sections. In this embodiment, the mixing section 3 includes a first mixing section 31, a second mixing section 32, a third mixing section 33 and a fourth mixing section 34 in order from the front to the rear, and the bottom diameter of the main thread 5 on the first mixing section 31 The outer diameter gradually decreases from front to back, and the bottom diameter and the outer diameter of the main thread 5 on the second mixing section 32 gradually increase from front to back, and the bottom diameter and the outer diameter of the main thread 5 on the third mixing section 33 are all from the front. After the gradual decrease, the bottom diameter and the outer diameter of the main thread 5 on the fourth mixing section 34 gradually increase from front to back, and the bottom diameter and the outer diameter of the auxiliary thread 6 on the first mixing section 31 gradually increase from front to back. The bottom diameter and the outer diameter of the secondary thread 6 on the second mixing section 32 are gradually decreased from front to back, and the bottom diameter and the outer diameter of the secondary thread 6 on the third mixing section 33 are gradually increased from front to back, and fourth. The bottom and outer diameters of the secondary threads 6 on the mixing section 34 are gradually reduced from front to back.
以下采用一组具体设计参数对本螺杆作进一步说明（参考图 2和 图 3， 图 2中曲线 11、 13分别示出螺杆上主螺纹 5的底径及外径的 变化规律， 图 3中曲线 12、 14分别示出压缩分离段 2及混合段 3上 副螺纹 6的底径及外径的变化规律）： 螺杆的长径比为 34.2: 1。进料 段 1 的长度为 9Ds (Ds表示螺杆外径， 即进料段 1上主螺纹 5的外 径）、 主螺纹 5的螺棱宽度为 0.1Ds、 主螺纹 5的底径为 0.65Ds; 进 料段 1前段的长度为 7Ds， 进料段 1后段的长度为 2Ds， 进料段 1前 段上主螺纹 5的螺距为 IDs,进料段 1后段前端的主螺纹 5的螺距为 IDs, 进料段 1后段后端的主螺纹 5螺距为 1.2Ds。 压缩分离段 2的 长度为 10.7Ds， 压缩分离段前段 21 的长度为 0.6Ds， 压縮分离段后 段 22的长度为 lO. lDs; 压缩分离段 2上主螺纹 5和副螺纹 6的螺距 均为 1.2Ds， 压缩分离段 2上副螺纹 6起始端与主螺纹 5 的距离为 0.32Ds,压缩分离段上 2主螺纹 5的底径由 0.65Ds逐渐增大到 0.94Ds， 压缩分离段前段 21上副螺纹 6的底径由 0.65DS逐渐增大到 0.88Ds， 压缩分离段后段 22上副螺纹 6的底径由 0.88DS逐渐减小到 0.7Ds。 混合段 3的长度为 l lDs, 第一混合小段 31、 第二混合小段 32、 第三 混合小段 33和第四混合小段 34的长度分别为 3.7Ds、 2.4Ds、 2.4Ds、 2.5Ds; 第一混合小段 31 上主螺纹 5 的底径由 0.94Ds逐渐减小到 0.79DS (第一混合小段 31上主螺纹 5起始端的底径与压缩分离段 2 上主螺纹 5末端的底径一致），第二混合小段 32上主螺纹 5的底径由 0.79Ds逐渐增大到 0.91Ds， 第三混合小段 33上主螺纹 5 的底径由 0.91Ds逐渐减小到 0.8Ds，第四混合小段 34上主螺纹 5的底径由 0.8Ds 逐渐增大到 0.9Ds (第四混合小段 34上主螺纹 5末端的底径与计量段 4上主螺纹 5的底径一致）； 第一混合小段 31上副螺纹 6的底径由 0.7Ds逐渐增大到 0.92DS (第一混合小段 31上副螺纹 6起始端的底 径与压缩分离段 2上副螺纹 6末端的底径一致），第二混合小段 32上 副螺纹 6的底径由 0.92Ds逐渐减小到 0.79Ds，第三混合小段 33上副 螺纹 6的底径由 0.79Ds逐渐增大到 0.93Ds，第四混合小段 34上副螺 纹 6的底径由 0.93DS逐渐减小到 0.9Ds (第四混合小段 34上副螺纹 6末端的底径与计量段 4上主螺纹 5的底径一致）； 混合段 3上主螺 纹 5和副螺紋 6的螺距均为 1.2Ds。 计量段 4的长度为 3.5Ds、 主螺 纹 5的螺棱宽度为 0.1Ds、 主螺纹 5的底径为 0.9Ds， 计量段 4前段 的长度为 2 Ds， 计量段 4后段的长度为 1.5 Ds， 计量段 4前段前端的 主螺纹 5的螺距为 1.2 Ds, 计量段 4前段后端的主螺纹 5的螺距为 IDs, 计量段 4后段上主螺纹 5的螺距为 lDs。 下面简述一下具有本螺杆的单螺杆挤出机的工作原理： 在进料段 1， 物料进入螺杆并熔化， 输送给压缩分离段 2。 压缩分离段 2具有熔体螺槽 7和固体螺槽 8， 随着物料的输送， 固体螺槽 8中的固体物料逐渐熔融变成熔体，并进入到熔体螺槽 7中。 压缩分离段 2能够将物料中的熔体与未熔融的固体分开，提高熔融效 率， 初步对物料进行塑化。 混合段 3上主副螺纹底径交替发生变化 （呈波纹状）， 实现物料 的压缩、放松的交替发生， 最终使来自压缩分离段 2的物料完全塑化 并混合均匀。 混合段 3上， 在主螺纹 5底径较大的位置， 第一熔体螺 槽 9中的物料能够越过副螺纹 6顶部并溢流到第二熔体螺槽 10中； 在副螺纹 6底径较大的位置， 第二熔体螺槽 10中的物料能够越过主 螺纹 5顶部并溢流到第一熔体螺槽 9中， 这样， 在物料 （熔融物料） 沿混合段 3 自前至后输送的过程中，第一熔体螺槽 9与第二熔体螺槽 10相互之间能够进行物料交流， 使物料混合更加均匀。 The screw is further described below using a set of specific design parameters (refer to FIG. 2 and FIG. 3, and curves 11 and 13 in FIG. 2 respectively show the variation of the bottom diameter and the outer diameter of the main thread 5 on the screw, and curve 12 in FIG. 14 shows the change of the bottom diameter and the outer diameter of the secondary thread 6 on the compression separation section 2 and the mixing section 3 respectively: The length to diameter ratio of the screw is 34.2:1. The length of the feed section 1 is 9Ds (Ds represents the outer diameter of the screw, that is, the outer diameter of the main thread 5 on the feed section 1), the width of the main thread 5 is 0.1Ds, and the bottom diameter of the main thread 5 is 0.65Ds; The length of the front section of the feed section 1 is 7Ds, the length of the rear section of the feed section 1 is 2Ds, the pitch of the main thread 5 on the front section of the feed section 1 is IDs, and the pitch of the main thread 5 at the front end of the feed section 1 is IDs. The pitch of the main thread 5 at the rear end of the rear section of the feed section 1 is 1.2 Ds. The length of the compression separation section 2 is 10.7Ds, the length of the front section 21 of the compression separation section is 0.6Ds, and the length of the rear section 22 of the compression separation section is lO. lDs; the pitch of the main thread 5 and the secondary thread 6 on the compression separation section 2 are both For 1.2Ds, the distance between the starting end of the secondary thread 6 and the main thread 5 on the compression separation section 2 is 0.32Ds, and the bottom diameter of the 2 main thread 5 on the compression separation section is gradually increased from 0.65Ds to 0.94Ds, and the compression separation section front section 21 The bottom diameter of the upper secondary thread 6 is gradually increased from 0.65DS to 0.88Ds, and the bottom diameter of the secondary thread 6 on the rear section 22 of the compression separation section is gradually reduced from 0.88DS to 0.7Ds. The length of the mixing section 3 is l lDs, and the lengths of the first mixing section 31, the second mixing section 32, the third mixing section 33 and the fourth mixing section 34 are respectively 3.7 Ds, 2.4 Ds, 2.4 Ds, 2.5Ds; the bottom diameter of the main thread 5 on the first mixing section 31 is gradually reduced from 0.94Ds to 0.79DS (the bottom diameter of the starting end of the main thread 5 on the first mixing section 31 and the end of the main thread 5 on the compression separation section 2) The bottom diameter is uniform), the bottom diameter of the main thread 5 on the second mixing section 32 is gradually increased from 0.79 Ds to 0.91 Ds, and the bottom diameter of the main thread 5 on the third mixing section 33 is gradually reduced from 0.91 Ds to 0.8 Ds, The bottom diameter of the main thread 5 on the four mixing section 34 is gradually increased from 0.8 Ds to 0.9 Ds (the bottom diameter of the end of the main thread 5 on the fourth mixing section 34 coincides with the bottom diameter of the main thread 5 on the metering section 4); The bottom diameter of the secondary thread 6 on the mixing section 31 is gradually increased from 0.7 Ds to 0.92 DS (the bottom diameter of the starting end of the secondary thread 6 on the first mixing section 31 coincides with the bottom diameter of the end of the secondary thread 6 on the compression separation section 2), The bottom diameter of the secondary thread 6 on the second mixing section 32 is gradually reduced from 0.92 Ds to 0.79 Ds, and the bottom diameter of the secondary thread 6 on the third mixing section 33 is gradually increased from 0.79 Ds to 0.93 Ds, and the fourth mixing section 34 is The bottom diameter of the secondary thread 6 is gradually reduced from 0.93DS to 0.9Ds (the bottom diameter of the end of the secondary thread 6 on the fourth mixing section 34 and the bottom of the main thread 5 of the metering section 4) The diameter is consistent); the pitch of the main thread 5 and the secondary thread 6 on the mixing section 3 are both 1.2 Ds. The length of the metering section 4 is 3.5Ds, the width of the main thread 5 is 0.1Ds, the diameter of the main thread 5 is 0.9Ds, the length of the front section of the metering section 4 is 2 Ds, and the length of the rear section of the metering section 4 is 1.5 Ds. The pitch of the main thread 5 at the front end of the front section of the metering section 4 is 1.2 Ds, the pitch of the main thread 5 at the rear end of the front section of the metering section 4 is IDs, and the pitch of the main thread 5 on the rear section of the metering section 4 is lDs. The working principle of the single-screw extruder with the screw will be briefly described below: In the feed section 1, the material enters the screw and is melted and sent to the compression separation section 2. The compression separation section 2 has a melt channel 7 and a solid groove 8, and as the material is transported, the solid material in the solid channel 8 gradually melts into a melt and enters the melt channel 7. The compression separation section 2 is capable of separating the melt in the material from the unmelted solids, improving the melting efficiency, and initially plasticizing the material. The bottom and bottom threads of the mixing section 3 alternately change (corrugated), which alternates the compression and relaxation of the material, and finally completely plasticizes the material from the compression separation section 2. And mix well. On the mixing section 3, at the position where the bottom diameter of the main thread 5 is large, the material in the first melt channel 9 can pass over the top of the secondary thread 6 and overflow into the second melt channel 10; At a larger diameter, the material in the second melt channel 10 can pass over the top of the main thread 5 and overflow into the first melt channel 9, thus, in the material (melt material) along the mixing section 3 from front to back During the conveying process, the first melt channel 9 and the second melt channel 10 can exchange materials with each other to make the material mixing more uniform.
计量段 4使来自混合段 3的物料熔融均化并定量输送至挤出机模 头。  Metering section 4 melts the material from mixing section 3 and homogenizes it to the extruder die.

Claims

权利要求述 Claims
1、 一种单螺杆挤出机的螺杆， 自前至后依次包括进料段、 压縮 分离段和计量段， 进料段上设有主螺纹， 压缩分离段上设有主螺纹和 副螺纹， 计量段上设有主螺纹， 其特征是： 所述压缩分离段与计量段 之间设有混合段， 混合段上设有主螺纹和副螺纹， 混合段自前至后依 次包括多个混合小段，其中第奇数个混合小段上主螺纹的底径自前至 后逐渐减小、副螺纹的底径自前至后逐渐增大， 第偶数个混合小段上 主螺纹的底径自前至后逐渐增大、 副螺纹的底径自前至后逐渐减小。 1. The screw of a single-screw extruder includes a feed section, a compression separation section and a metering section from front to back. The feed section is provided with a main thread, and the compression separation section is provided with a main thread and a secondary thread. The metering section is provided with a main thread, which is characterized by: a mixing section is provided between the compression separation section and the metering section, the mixing section is provided with a main thread and a secondary thread, and the mixing section includes a plurality of small mixing sections from front to back. Among them, the bottom diameter of the main thread on the odd-numbered mixing section gradually decreases from front to back, and the bottom diameter of the secondary thread gradually increases from front to back. The bottom diameter of the main thread on the even-numbered mixing section gradually increases from front to back, and the bottom diameter of the secondary thread gradually increases from front to back. The bottom diameter of the thread gradually decreases from front to back.
2、 根据权利要求 1所述的单螺杆挤出机的螺杆， 其特征是： 所 述混合段上， 第奇数个混合小段上主螺纹的外径自前至后逐渐减小、 副螺纹的外径自前至后逐渐增大，第偶数个混合小段上主螺纹的外径 自前至后逐渐增大、 副螺纹的外径自前至后逐渐减小。 2. The screw of a single-screw extruder according to claim 1, characterized in that: on the mixing section, the outer diameter of the main thread on the odd-numbered mixing section gradually decreases from front to back, and the outer diameter of the secondary thread gradually decreases from front to back. It gradually increases from front to back. The outer diameter of the main thread on the even-numbered mixing section gradually increases from front to back, and the outer diameter of the secondary thread gradually decreases from front to back.
3、根据权利要求 1或 2所述的单螺杆挤出机的螺杆， 其特征是： 所述混合段自前至后依次包括 3— 6个混合小段。 3. The screw of the single-screw extruder according to claim 1 or 2, characterized in that: the mixing section includes 3-6 small mixing sections from front to back.
4、 根据权利要求 2所述的单螺杆挤出机的螺杆， 其特征是： 所 述混合段自前至后依次包括第一混合小段、第二混合小段、第三混合 小段和第四混合小段，第一混合小段上主螺纹的底径和外径均自前至 后逐渐减小，第二混合小段上主螺纹的底径和外径均自前至后逐渐增 大， 第三混合小段上主螺纹的底径和外径均自前至后逐渐减小， 第四 混合小段上主螺纹的底径和外径均自前至后逐渐增大，第一混合小段 上副螺纹的底径和外径均自前至后逐渐增大，第二混合小段上副螺纹 的底径和外径均自前至后逐渐减小，第三混合小段上副螺纹的底径和 外径均自前至后逐渐增大，第四混合小段上副螺纹的底径和外径均自 前至后逐渐减小。 4. The screw of a single-screw extruder according to claim 2, characterized in that: the mixing section includes a first mixing section, a second mixing section, a third mixing section and a fourth mixing section from front to back, The bottom diameter and outer diameter of the main thread on the first mixing section gradually decrease from front to back. The bottom diameter and outer diameter of the main thread on the second mixing section gradually increase from front to back. The main thread on the third mixing section gradually increases. Both the bottom diameter and the outer diameter gradually decrease from front to back. The bottom diameter and outer diameter of the main thread on the fourth mixing section gradually increase from front to back. The bottom diameter and outer diameter of the auxiliary thread on the first mixing section both increase from front to back. Then it gradually increases. The bottom diameter and outer diameter of the secondary thread on the second mixing section gradually decrease from front to back. The bottom diameter and outside diameter of the secondary thread on the third mixing section gradually increase from front to back. The fourth mixing section gradually increases. The bottom diameter and outer diameter of the secondary thread on the small section gradually decrease from front to back.
5、 根据权利要求 1、 2或 4所述的单螺杆挤出机的螺杆， 其特征 是： 所述压缩分离段上主螺纹的底径自前至后逐渐增大； 压縮分离段 包括压缩分离段前段和压缩分离段后段，压缩分离段前段上副螺纹的 底径自前至后逐渐增大，压缩分离段后段上副螺纹的底径自前至后逐 渐减小， 所述压缩分离段前段的长度占压缩分离段总长度的 3— 7 %。 5. The screw of a single-screw extruder according to claim 1, 2 or 4, characterized in that: the bottom diameter of the main thread on the compression separation section gradually increases from front to back; the compression separation section includes compression separation The front section of the compression separation section and the rear section of the compression separation section, the secondary thread on the front section of the compression separation section The bottom diameter gradually increases from front to back, and the bottom diameter of the secondary thread on the rear section of the compression separation section gradually decreases from front to back. The length of the front section of the compression separation section accounts for 3-7% of the total length of the compression separation section.
6、 根据权利要求 5所述的单螺杆挤出机的螺杆， 其特征是： 所 述压縮分离段上主螺纹的外径保持一致、 副螺纹的外径也保持一致， 压缩分离段上副螺纹的外径小于主螺纹的外径。 6. The screw of a single-screw extruder according to claim 5, characterized in that: the outer diameter of the main thread on the compression separation section remains consistent, the outer diameter of the secondary thread also remains consistent, and the secondary thread on the compression separation section also remains consistent. The outer diameter of the thread is smaller than the outer diameter of the main thread.
PCT/CN2013/001114 2013-03-09 2013-09-22 Screw rod of single screw extruder WO2014139065A1 (en)

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