Annular gap discharging device of extruder and control method of annular gap discharging device

Abstract

The invention provides an extruder annular space discharging device and a control method thereof, and relates to an extruder structure, the extruder annular space discharging device comprises a discharging lining, a tail end screw, a tip cone and an annular space driving device, the tail end screw is installed at the tail end of an equipment main shaft of an extruder, the axial position of the tail end screw in an equipment cylindrical main body is located in the discharging lining at the tail end of the tail end screw, and the tip cone is installed on the discharging lining. The annular space driving device is installed on an installation base at the tail end of the equipment cylindrical body, the tip cone is installed at the driving end of the annular space driving device, the tip cone is driven by the annular space driving device to move towards the tail end screw rod, and when the tip cone stretches into the discharging lining, the tip cone, the discharging lining and the tip cone jointly form a discharging annular space for materials. And the automatic control of the size of the annular gap is realized, so that the flexibility of adjusting the size of the annular gap when the extruder is used is improved, and the uniformity of the quality of a discharged product is ensured.

Description

Technical Field

[0001] The invention relates to an extruder structure, in particular to an extruder annular gap discharging device and a control method thereof. Background Art

[0002] Annular gap discharging is achieved by forming an annular gap at the outlet of the equipment. The material is extruded under the pressure and temperature provided by the screw inside the equipment to achieve the expansion effect. This process can significantly increase the volume of the material, improve its texture and taste, and increase the utilization rate of raw materials. And because the annular gap discharging has the technical characteristics of continuity, uniformity and controllability, it has been widely used in many fields, such as food processing (popcorn, potato chips, etc.), feed processing (such as livestock and poultry feed, aquatic feed, pig feed, pet food, etc.), plastic industry (for the manufacture of plastic particles and their products), etc.

[0003] However, the existing annular gap discharging still has many application defects as shown below:

[0004] 1) Blockage problem, specifically: the annular gap is small, which is prone to blockage due to the accumulation of particles or other impurities, which will cause the production line to stop and affect production efficiency;

[0005] 2) Wear problem, specifically: under high pressure and high temperature conditions, especially in the continuous production process, the annular gap is easily worn. In addition, the friction of the material on the inner wall of the equipment will also aggravate the wear problem;

[0006] 3) The setting is complicated, specifically: the size of the annular gap needs to be accurately set to ensure that the material can be extruded evenly; the traditional annular gap discharge in the early days was set by manually adjusting the position of the nut. If the setting is improper, it will lead to uneven discharge and affect product quality;

[0007] 4) Cloak phenomenon: due to uneven pressure during discharge, part of the material will adhere to the inside of the equipment, forming a "cloak" phenomenon, which will reduce the discharge efficiency and may cause irregular product size and shape. Summary of the invention

[0008] In order to solve the above technical problems, the purpose of the present invention is to provide an extruder annular gap discharging device and a control method thereof, which realizes automatic control of the annular gap size through hydraulic drive, thereby improving the flexibility of adjusting the annular gap size of the extruder when in use, and ensuring the uniformity of the quality of the discharged product; and through the specially designed tail screw and hydraulic top cone, the material has better fluidity and more uniform pressure distribution when flowing through the annular gap, reducing the "cloak" phenomenon, and improving production efficiency and product quality.

[0009] The present invention provides the following technical solutions:

[0010] An annular gap discharge device for an extruder comprises a discharge bushing, a tail end screw, a top cone and an annular gap drive device, wherein the tail end screw is mounted at the tail end of the equipment main shaft of the extruder and rotates with the main shaft, and the equipment main shaft of the extruder is configured to rotate in the equipment cylindrical body, and the structure in which the equipment main shaft is configured in the equipment cylindrical body to extrude materials is a prior art of the extruder and will not be described in detail here, and the axial position of the tail end screw in the equipment cylindrical body is located in the discharge bushing at its tail end, and its axial position remains unchanged; the annular gap drive device is mounted on a mounting seat at the tail end of the equipment cylindrical body, and the top cone is mounted on its driving end, and the top cone moves toward the tail end screw under the drive of the annular gap drive device, and forms a discharge annular gap for the material together with the discharge bushing and the top cone when extending into the discharge bushing;

[0011] In the discharging device of the present invention, the discharging annular gap can be driven and adjusted by an annular gap driving device to realize automatic control of the annular gap size, thereby improving the flexibility of adjusting the annular gap size of the extruder when in use and ensuring the uniformity of the quality of the discharging product.

[0012] Preferably, the annular gap driving device adopts a hydraulic cylinder, whose piston rod is connected to the top cone, and the rodless chamber in the cylinder body is connected to the overflow valve to control the oil pressure in the rodless chamber; when the oil pressure in the rodless chamber exceeds the pressure setting value, the overflow valve releases pressure; that is, the hydraulic system of the hydraulic cylinder can form the following effect: after the oil pump drives the hydraulic oil into the rodless chamber, if the discharge port does not have sufficient load, the piston rod of the hydraulic cylinder will continue to extend until the full stroke, and the oil pressure in the rodless chamber exceeds the pressure setting value (such as the set pressure is 20bar), the overflow valve releases pressure; if the discharge port has sufficient load, the piston rod will extend to the equilibrium position, and the oil pressure in the rodless chamber is also set to exceed 20bar, then the overflow valve releases pressure to avoid blockage; at this point, the effect of intelligent blockage prevention can be achieved, that is, the annular gap adjustment is driven by the hydraulic system.

[0013] Preferably, the tail end screw includes a cone block 1 for being fixedly connected to the tail end of the equipment main shaft and a plurality of groups of claws uniformly fixed around the periphery of the cone block 1, the claws are inclined from their fixed ends toward one end of the top cone, the top cone includes a cone block 2 and a surrounding edge arranged outside the cone block 2, when the top cone is docked with the tail end screw, the surrounding edge is wrapped outside the claw, and its outer diameter is slightly smaller than the inner diameter of the discharge bushing, and a plurality of groups of grooves for material outflow are evenly arranged on the surrounding edge, so that the tail end screw and the top cone are used in combination, which can make the discharge pressure more uniform, reduce material adhesion, and reduce the "cloak" phenomenon, the discharge trough is arranged on the top cone, and the tail end screw rotates with the equipment main shaft, and the collision-ripened material in the extruder can be discharged through the discharge trough of the top cone, that is, the trough, and the trough can also be designed to be of different numbers or shapes according to different needs.

[0014] Preferably, the grooves are a plurality of through circular holes evenly arranged on the surrounding edge.

[0015] Preferably, the grooves are a plurality of through grooves evenly arranged on the surrounding edge.

[0016] Preferably, when the top cone is docked with the tail end screw, the claw member is arranged to fit on the outer conical surface of cone block 2. The structural coordination between the claw member and cone block can ensure that the tail end screw will not touch the top cone during rotation. At the same time, the annular gap formed between the conical surface formed by rotation and the top cone is more equal, so that the discharge pressure at different directions of the discharge port is more uniform.

[0017] Preferably, the tail end screw, the top cone and the discharge bushing are all made of wear-resistant materials, which can extend the service life of the device; and they can be disassembled and replaced to reduce maintenance costs.

[0018] Preferably, a control system is also included, which adopts PLC control and integrated PID automatic adjustment; through parameter setting, the size of the annular gap can be automatically adjusted according to the actual production situation, thereby reducing human errors and ensuring the uniformity of product quality.

[0019] A control method for an annular gap discharging device of an extruder comprises the following steps:

[0020] S1: In the initial state, the annular gap drive device drives the top cone to retreat to the end away from the tail screw, forming the maximum gap between the top cone and the tail screw, making it easy to start production;

[0021] S2: After the system process starts production, the material enters from the feed port of the cylindrical body of the equipment and is discharged from the discharge bushing port. The oil pump drives the hydraulic oil into the rodless chamber of the hydraulic cylinder to provide the pressure required for the extruder production, and then controls the movement of the piston rod of the annular gap drive device to drive the top cone to move slowly axially toward the tail end screw, so that the tail end screw and the top cone and the discharge bushing form a discharge annular gap for the material. At this time, the internal pressure in the extruder increases, which is used to make the material expand and mature.

[0022] Preferably, the limit value of the equipment load, such as the oil pressure of the rodless chamber and the limit value of the equipment mechanical energy, is set in the control system. When the equipment load exceeds the set value, the annular gap is automatically increased to reduce the equipment load, avoid blockage and shutdown, and improve production continuity.

[0023] The system does not require the participation of traditional pressure sensors, has fewer components, lower costs, and can achieve richer control modes through reasonable control logic; the system can also achieve three modes to control the annular gap discharge, namely: constant annular gap, constant annular gap pressure and automatic annular gap adjustment;

[0024] The constant gap of the annular gap is not discussed here. The constant pressure of the annular gap is the logic of setting the pressure as shown above, such as setting the oil pressure of the rodless chamber to 20bar. As for the automatic adjustment of the annular gap, PID automatic adjustment is performed. During the adjustment, the parameters can be set according to the mechanical energy of the extruder and then switched to automatic mode. The mechanical energy is the energy input by the extruder to the processed material, and its unit is Wh / kg (watt-hour per kilogram) or kWh / t (kilowatt-hour per ton). The actual numerical calculation method is: the driving power of the equipment spindle (W) / output (kg / h). The driving motor of the extruder equipment spindle is operated at industrial frequency, so the motor current can correspond to the driving power. The feeding amount of the feeder can be collected to know the output. The mechanical energy SME is obtained by dividing the two. In the production process, by maintaining constant mechanical energy, stable product quality can be obtained = stable aging effect:

[0025] During automatic adjustment, when the actual mechanical energy (Wh / kg) of the extruder is greater than the set value of the mechanical energy and exceeds the deviation range, the control system will control the reduction of the overflow valve output. At this time, the rodless chamber pressure of the annular gap drive device decreases, the top cone retreats under the thrust of the material, the annular gap increases, the load of the extruder host decreases, and the actual mechanical energy decreases;

[0026] When the actual mechanical energy (Wh / kg) is less than the set value of the mechanical energy and exceeds the deviation range, the control system will increase the output of the relief valve. At this time, the rodless chamber pressure of the annular gap drive device increases, the top cone extends under the thrust of the oil, the annular gap decreases, the load of the extruder host increases (but still lower than the safety value of the extruder host load), and the actual mechanical energy increases;

[0027] When an emergency occurs and causes the extruder host load to exceed the safety value (such as 100% and lasts for 3 seconds), the control system will suspend the automatic mode and open the overflow valve according to the background preset proportional overflow valve opening (such as 20%) to quickly release the pressure, reduce the extruder host load, and protect the safety of the equipment.

[0028] The beneficial effects of the present invention are:

[0029] 1 In the discharging device of the present invention, the discharging annular gap can be driven and adjusted by the annular gap driving device to realize automatic control of the size of the annular gap, thereby improving the flexibility of adjusting the size of the annular gap of the extruder when in use, and ensuring the uniformity of the quality of the discharging product;

[0030] 2 In the discharging device of the present invention, the annular gap driving device adopts a hydraulic cylinder, the piston rod of the hydraulic cylinder is connected to the top cone, and the rodless cavity in the cylinder body is connected to the overflow valve to control the oil pressure in the rodless cavity;

[0031] When the oil pressure in the rodless chamber exceeds the set pressure value, the relief valve releases pressure; that is, the hydraulic system of the hydraulic cylinder can form the following effect: after the oil pump drives the hydraulic oil into the rodless chamber, if the discharge port does not have sufficient load, the piston rod of the hydraulic cylinder will continue to extend until the full stroke, and when the oil pressure in the rodless chamber exceeds the set value (such as the set pressure is 20bar), the relief valve releases pressure; if the discharge port has sufficient load, the piston rod will extend to the equilibrium position, and the oil pressure in the rodless chamber is also set to exceed 20bar, the relief valve releases pressure to avoid blockage; at this point, the effect of intelligent blockage prevention can be achieved, that is, the ring gap adjustment is driven by the hydraulic system;

[0032] 3 The discharging device of the present invention may also include a control system, which may be controlled by PLC and integrated with PID automatic adjustment. By setting parameters, the size of the annular gap can be automatically adjusted according to actual production conditions, thereby reducing human errors and ensuring uniformity of product quality.

[0033] The limit values ​​of the equipment load, such as the oil pressure of the rodless cavity and the limit value of the equipment mechanical energy, are set in the control system. When the equipment load exceeds the set value, the annular gap is automatically increased to reduce the equipment load, avoid blockage and shutdown, and improve production continuity. The system does not require the participation of traditional pressure sensors, has fewer components and lower costs, and can achieve more diverse control modes through reasonable control logic. The system can also achieve three modes to control the annular gap discharge, namely: constant annular gap, constant annular gap pressure, and automatic annular gap adjustment.

[0034] The constant gap of the annular gap is not discussed here. The constant pressure of the annular gap is the logic of setting the pressure as shown above, such as setting the oil pressure of the rodless chamber to 20bar. As for the automatic adjustment of the annular gap, when executing the PID automatic adjustment, the parameters can be set according to the mechanical energy of the extruder and then switched to the automatic mode. The mechanical energy is the energy input by the extruder to the processed material, and its unit is Wh / kg (watt-hour per kilogram) or kWh / t (kilowatt-hour per ton). The actual numerical calculation method is: the driving power of the equipment spindle (W) / output (kg / h). The driving motor of the extruder equipment spindle is operated at industrial frequency, so the motor current can correspond to the driving power. The output can be known by collecting the feeding amount of the feeder. The mechanical energy SME is obtained by dividing the two. In the production process, by maintaining constant mechanical energy, stable product quality can be obtained = stable aging effect:

[0035] During automatic adjustment, when the actual mechanical energy (Wh / kg) of the extruder is greater than the set value of the mechanical energy and exceeds the deviation range, the control system will control the reduction of the overflow valve output. At this time, the rodless chamber pressure of the annular gap drive device decreases, the top cone retreats under the thrust of the material, the annular gap increases, the load of the extruder host decreases, and the actual mechanical energy decreases;

[0036] When the actual mechanical energy (Wh / kg) is less than the set value of the mechanical energy and exceeds the deviation range, the control system will increase the output of the relief valve. At this time, the rodless chamber pressure of the annular gap drive device increases, the top cone extends under the thrust of the oil, the annular gap decreases, the load of the extruder host increases (but still lower than the safety value of the extruder host load), and the actual mechanical energy increases;

[0037] When an unexpected event causes the extruder host load to exceed the safety value (such as reaching 100% and lasting for 3 seconds), the control system will suspend the automatic mode and open the overflow valve according to the background preset proportional overflow valve opening (such as 20%) to quickly release the pressure, reduce the extruder host load, and protect the safety of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0039] Figure 1 It is a structural cross-sectional view of the tail end screw and the top cone when they are butted together in the present invention;

[0040] Figure 2 It is a structural cross-sectional view of the present invention when the tail end screw and the top cone are separated;

[0041] Figure 3 It is a structural cross-sectional view of the present invention when the tail end screw and the top cone form an annular gap;

[0042] Figure 4 It is a schematic diagram of the structure of the tail end screw;

[0043] Figure 5 1. It is a schematic diagram of the top cone structure when the groove is a through circular hole;

[0044] Figure 6 It is a schematic diagram of the top cone structure when the groove is a through groove;

[0045] Figure 7 1. It is a schematic diagram of the top cone structure when the groove is another through groove;

[0046] Markings in the figure:

[0047] 1. tail end screw; 2. top cone; 3. annular gap driving device; 4. discharge bushing; 5. mounting seat; 11. cone block 1; 12. claw piece; 21. cone block 2; 22. surrounding edge; 23. through circular hole; 24. through slot. DETAILED DESCRIPTION

[0048] Example 1

[0049] like Figure 1-7As shown, an annular gap discharge device for an extruder, in this embodiment, includes a discharge bushing 4, a tail end screw 1, a top cone 2 and an annular gap drive device 3, the tail end screw 1 is installed at the tail end of the equipment main shaft of the extruder, and rotates with the main shaft, the equipment main shaft of the extruder is configured to rotate in the equipment cylindrical body, the structure in which the equipment main shaft is configured in the equipment cylindrical body to extrude materials is the existing technology of the extruder, and it is not repeated here, and the axial position of the tail end screw 1 in the equipment cylindrical body is located in the discharge bushing 4 at its tail end, and its axial position remains unchanged; the annular gap drive device 3 is installed on the mounting seat 5 at the tail end of the equipment cylindrical body, and the top cone 2 is installed at its driving end, and the top cone 2 moves toward the tail end screw 1 under the drive of the annular gap drive device 3, and when extending into the discharge bushing 4, it forms a discharge annular gap for the material together with the discharge bushing 4 and the top cone 2;

[0050] In the discharging device of the present invention, the discharging annular gap can be driven and adjusted by the annular gap driving device 3 to realize automatic control of the annular gap size, thereby improving the flexibility of adjusting the annular gap size of the extruder when in use and ensuring the uniformity of the quality of the discharging product.

[0051] The annular gap driving device 3 adopts a hydraulic cylinder, whose piston rod is connected to the top cone 2, and the rodless chamber in the cylinder body is connected to the overflow valve to control the oil pressure in the rodless chamber; when the oil pressure in the rodless chamber exceeds the set value, the overflow valve releases pressure; that is, the hydraulic system of the hydraulic cylinder can form the following effect: after the oil pump drives the hydraulic oil into the rodless chamber, if the discharge port does not have enough load, the piston rod of the hydraulic cylinder will continue to extend until the full stroke, and when the oil pressure in the rodless chamber exceeds the set value (such as the set pressure is 20bar), the overflow valve releases pressure; if the discharge port has enough load, the piston rod will extend to the equilibrium position, and after the oil pressure in the rodless chamber is also set to exceed 20bar, the overflow valve releases pressure to avoid blockage; at this point, the effect of intelligent blockage prevention can be achieved, that is, the annular gap adjustment is driven by the hydraulic system;

[0052] The tail end screw 1 includes a cone block 11 fixedly connected to the tail end of the equipment main shaft and multiple groups of claws 12 uniformly fixed around the cone block 11. The claw 12 is inclined from its fixed end to one end of the top cone 2. The top cone 2 includes a cone block 21 and a surrounding edge 22 surrounded by the cone block 21. When the top cone 2 is docked with the tail end screw 1, the surrounding edge 22 is wrapped outside the claw 12, and its outer diameter is slightly smaller than the inner diameter of the discharge bushing 4. There are also multiple groups of grooves for material outflow evenly arranged on the surrounding edge 22. At this point, the tail end screw 1 and the top cone 2 are used together to make the discharge pressure more uniform, reduce material adhesion, and reduce the "cloak" phenomenon. The discharge trough is opened on the top cone 2, and the tail end screw 1 rotates with the equipment main shaft. The material that has collided and matured in the extruder can be discharged through the discharge trough of the top cone 2, that is, the trough. At the same time, the trough can be designed to be different in number or shape according to different needs, as follows:

[0053] As shown in FIG. 5 , the grooves are a plurality of through circular holes 23 evenly arranged on the surrounding edge 22 .

[0054] As shown in Figures 6-7, the grooves are a plurality of through slots 24 evenly arranged on the surrounding edge 22.

[0055] When the top cone 2 is docked with the tail end screw 1, the claw member 12 is arranged to fit on the outer conical surface of the cone block 21. The structural matching mode of the claw member 12 and the cone block can ensure that the tail end screw 1 will not touch the top cone 2 during rotation. At the same time, the annular gap formed between the conical surface formed by rotation and the top cone 2 is more equal, so that the discharge pressure at different directions of the discharge port is more uniform.

[0056] The tail end screw 1, the top cone 2 and the discharge bushing 4 are all made of wear-resistant materials, which can extend the service life of the device; and can be disassembled and replaced to reduce maintenance costs.

[0057] Example 2

[0058] A control method for an annular gap discharging device of an extruder comprises the following steps:

[0059] S1: In the initial state, the annular gap driving device 3 drives the top cone 2 to retreat to the end away from the tail screw 1, forming the maximum gap between the top cone 2 and the tail screw 1, which is easy to start production;

[0060] S2: After the system process starts production, the material enters from the feed port of the cylindrical body of the equipment and is discharged from the port of the discharge bushing 4. The oil pump drives the hydraulic oil into the rodless chamber of the hydraulic cylinder to provide the pressure required for the extruder production, and then controls the movement of the piston rod of the annular gap driving device 3 to drive the top cone 2 to move slowly axially toward the tail end screw 1, so that the tail end screw 1 and the top cone 2 and the discharge bushing 4 form a discharge annular gap for the material. At this time, the internal pressure in the extruder increases, which is used to make the material expand and mature.

[0061] The discharging device of the present invention may further include a control system, which may be controlled by PLC and integrated with PID automatic adjustment. By setting parameters, the size of the annular gap can be automatically adjusted according to actual production conditions, thereby reducing human errors and ensuring uniformity of product quality.

[0062] The limit values ​​of the equipment load, such as the oil pressure of the rodless cavity and the limit value of the equipment mechanical energy, are set in the control system. When the equipment load exceeds the set value, the annular gap is automatically increased to reduce the equipment load, avoid blockage and shutdown, and improve production continuity. The system does not require the participation of traditional pressure sensors, has fewer components and lower costs, and can achieve more diverse control modes through reasonable control logic. The system can also achieve three modes to control the annular gap discharge, namely: constant annular gap, constant annular gap pressure, and automatic annular gap adjustment.

[0063] The constant gap of the annular gap is not discussed here. The constant pressure of the annular gap is the logic of the set pressure shown in the above. For example, the oil pressure of the rodless chamber is set to 20bar. As for the automatic adjustment of the annular gap, PID automatic adjustment is performed. During the adjustment, the parameters can be set according to the mechanical energy of the extruder and then switched to automatic mode. Mechanical energy is the energy input by the extruder to the processed material. Its unit is Wh / kg (watt-hour per kilogram) or kWh / t (kilowatt-hour per ton). The actual numerical calculation method is: the driving power of the equipment spindle (W) / output (kg / h). The driving motor of the extruder equipment spindle is operated at industrial frequency, so the motor current can correspond to the driving power. The output can be known by collecting the feeding amount of the feeder. The mechanical energy SME is obtained by dividing the two. In the production process, by maintaining constant mechanical energy, stable product quality can be obtained = stable aging effect:

[0064] During automatic adjustment, when the actual mechanical energy (Wh / kg) of the extruder is greater than the set value of the mechanical energy and exceeds the deviation range, the control system will control the reduction of the overflow valve output. At this time, the rodless chamber pressure of the annular gap drive device 3 decreases, the top cone 2 retreats under the thrust of the material, the annular gap increases, the load of the extruder host decreases, and the actual mechanical energy decreases;

[0065] When the actual mechanical energy (Wh / kg) is less than the set value of the mechanical energy and exceeds the deviation range, the control system will increase the output of the overflow valve. At this time, the pressure of the rodless chamber of the annular gap drive device 3 increases, the top cone 2 extends under the thrust of the oil, the annular gap decreases, the load of the extruder mainframe increases (but still lower than the safety value of the extruder mainframe load), and the actual mechanical energy increases;

[0066] When an unexpected event causes the extruder host load to exceed the safety value (such as reaching 100% and lasting for 3 seconds), the control system will suspend the automatic mode and open the overflow valve according to the background preset proportional overflow valve opening (such as 20%) to quickly release the pressure, reduce the extruder host load, and protect the safety of the equipment.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An extruder annular gap discharging device, characterized in that: The invention comprises a discharge bushing (4), a tail screw (1), a top cone (2) and an annular gap driving device (3), wherein the tail screw (1) is mounted at the tail end of the main shaft of the extruder and rotates with the main shaft, the main shaft of the extruder is arranged to rotate in the cylindrical body of the equipment, and the axial position of the tail screw (1) in the cylindrical body of the equipment is located in the discharge bushing (4) at its tail end, and its axial position remains unchanged; the annular gap driving device (3) is mounted on a mounting seat (5) at the tail end of the cylindrical body of the equipment, and the top cone (2) is mounted on its driving end, and the top cone (2) moves toward the tail screw (1) under the drive of the annular gap driving device (3), and when extending into the discharge bushing (4), it forms a discharge annular gap for the material together with the discharge bushing (4) and the top cone (2).

2. An extruder annular gap discharging device according to claim 1, characterized in that: The annular gap driving device (3) adopts a hydraulic cylinder, the piston rod of which is connected to the top cone (2), and the rodless chamber in the cylinder body is connected to the overflow valve to control the oil pressure in the rodless chamber.

3. An extruder annular gap discharging device according to claim 2, characterized in that: The tail end screw (1) comprises a cone block (11) for being fixedly connected to the tail end of the main shaft of the equipment and a plurality of groups of claws (12) uniformly fixed around the periphery of the cone block (11), wherein the claws (12) are inclined from their fixed ends toward one end of the top cone (2), and the top cone (2) comprises a cone block (21) and a surrounding edge (22) surrounding the cone block (21). When the top cone (2) is docked with the tail end screw (1), the surrounding edge (22) is wrapped around the claws (12), and its outer diameter is slightly smaller than the inner diameter of the discharge bushing (4), and a plurality of groups of grooves for material outflow are uniformly provided on the surrounding edge (22).

4. An extruder annular gap discharging device according to claim 3, characterized in that: The grooves are a plurality of through circular holes (23) evenly arranged on the surrounding edge (22).

5. The extruder annular gap discharging device according to claim 3, characterized in that: The grooves are a plurality of through grooves (24) evenly arranged on the surrounding edge (22).

6. The extruder annular gap discharging device according to claim 3, characterized in that: When the top cone (2) is butt-jointed with the tail end screw (1), the claw member (12) is arranged to fit on the outer conical surface of the second cone block (21), and the claw member (12) and the cone block are matched in structure.

7. The extruder annular gap discharging device according to claim 1, characterized in that: The tail end screw (1), the top cone (2) and the discharge bushing (4) are all made of wear-resistant materials.

8. The extruder annular gap discharging device according to claim 1, characterized in that: It also includes a control system, which adopts PLC control and integrated PID automatic adjustment.

9. A control method for an annular gap discharge device of an extruder, characterized in that: The steps include: S1: In the initial state, the annular gap driving device (3) drives the top cone (2) to retreat to the end away from the tail screw (1), forming the maximum gap between the top cone (2) and the tail screw (1); S2: After the system process starts production, the material enters from the feed port of the cylindrical body of the equipment and is discharged from the discharge bushing (4) port. The oil pump drives the hydraulic oil into the rodless chamber of the hydraulic cylinder to provide the pressure required for the extruder production, and then controls the movement of the piston rod of the annular gap drive device (3) to drive the top cone (2) to move slowly axially toward the tail screw (1), so that the tail screw (1) and the top cone (2) and the discharge bushing (4) form a discharge annular gap for the material. At this time, the internal pressure in the extruder increases, which is used to expand and mature the material.

10. The control method of the annular gap discharging device of an extruder according to claim 9, characterized in that: For automatic adjustment of the annular gap, when performing PID automatic adjustment, switch to automatic mode after setting parameters in the control system according to the mechanical energy of the extruder, where the mechanical energy is the energy input by the extruder to the processed material; During automatic adjustment, when the actual mechanical energy of the extruder is greater than the set value of the mechanical energy and exceeds the deviation range, the control system will control the reduction of the overflow valve output. At this time, the rodless chamber pressure of the annular gap drive device decreases, the top cone retreats under the thrust of the material, the annular gap increases, the load of the extruder host decreases, and the actual mechanical energy decreases; When the actual mechanical energy is less than the set value of the mechanical energy and exceeds the deviation range, the control system will increase the output of the relief valve. At this time, the rodless chamber pressure of the annular gap drive device increases, the top cone extends under the thrust of the oil, the annular gap decreases, and the load of the extruder main machine increases, but it is still lower than the safety value of the extruder main machine load, and the actual mechanical energy increases; When an emergency occurs and the load of the extruder host exceeds the safety value, the control system will suspend the automatic mode and open the relief valve according to the preset proportional relief valve opening in the background to quickly release the pressure, reduce the load of the extruder host, and protect the safety of the equipment.

Images