Film bubble thickness fine adjustment device of film blowing machine

Abstract

The utility model relates to a film bubble thickness fine adjustment device of a film blowing machine, which comprises a machine base, an air supply device, an air ring, an air supply ring and a plurality of fine adjustment air control components, an annular air cavity is arranged in the air ring, the annular air cavity is divided into a plurality of air cavities along the circumferential direction of the annular air cavity, and each air cavity is communicated with the air supply device; the multiple micro-regulation air-conditioning assemblies are arranged on the air ring in the circumferential direction of the air ring, each micro-regulation air-conditioning assembly comprises a heating device and a thermal expansion pipe, the heating device is installed in the air cavity, the outer wall of the thermal expansion pipe is in contact fit with the heating device, and an outer end opening of the thermal expansion pipe is communicated with the air cavity; the air supplementing ring is arranged on the inner side of the air ring, a plurality of air supplementing channels are formed in the air supplementing ring and correspond to the air cavities one to one, and openings in the outer ends of the air supplementing channels are communicated with the inner ends of the corresponding thermal expansion pipes. The film bubble thickness fine adjustment device can accurately adjust the thickness of each local position in the circumferential direction of a film bubble after the film bubble is extruded, so that the thickness of each point in the circumferential direction of the film bubble becomes more uniform.

Description

Technical Field

[0001] The utility model relates to the technical field of film blowing equipment, in particular to a film bubble thickness fine adjustment device of a film blowing machine. Background Art

[0002] Blown film is the most widely used method in the production of plastic film. The blown film machine is a device that heats and melts plastic particles and then blows them into film. Its main working process is: the material is first plasticized by the extruder, then extruded into a cylindrical tube embryo (film bubble) through the die head, then cooled by the air ring and water ring, and then introduced into the traction roller for clamping after stabilization, folding, and flattening. Finally, it is rolled up by the winder to produce a film product with good strength, toughness, opening, moisture resistance, transparency and thermoplasticity.

[0003] When the film blowing machine is working, the molten material is extruded from the gap of the circular die of the machine head to form a circular film bubble. At the same time, pressurized gas is blown into the film bubble to inflate the film bubble. The greater the degree of inflation, the thinner the film bubble becomes. On the other hand, the temperature of the film bubble is high when it is extruded, so it is necessary to use a cooling air ring to cool it so that the film bubble can be finally shaped. The cooling air ring includes an annular main air duct located on the outside and an annular air outlet located on the inner edge. The annular main air duct is provided with a total air inlet. An annular air guide interlayer is provided between the annular main air duct and the annular air outlet. The annular main air duct is connected to the annular air outlet through the annular air guide interlayer. When working, the cooling air flow enters the annular main air duct from the total air inlet, and then is blown to the annular air outlet through the annular air guide interlayer. The annular air outlet is close to and faces the film bubble, thereby cooling the film bubble.

[0004] When the molten material enters the head of the film blowing equipment, it must only enter from a total feed port, and then gradually expands and distributes in the head and flows into the annular die gap. In the above expansion and distribution process, although people strive to keep the thickness and pressure of the molten material uniform at each point in the circumferential direction of the annular die gap, in reality, due to the errors of mechanical equipment and the limitations of the distribution channel itself, when the molten material is extruded from the annular die gap, the thickness of each point of the film bubble is difficult to be very uniform in the circumferential direction, that is, the thickness of the film bubble is uneven.

[0005] In the conventional technology, after the molten material is extruded from the annular die gap, the bubble thickness can be adjusted by adjusting the air volume of the air ring and the gas pressure inside the bubble (i.e., adjusting the bubble inflation ratio), but this thickness adjustment is systematic and global (i.e., when the thickness of a certain point in the circumference increases, the thickness of other points in the circumference must also increase, and vice versa), and it is not possible to fine-tune the thickness of local points in the circumference. Therefore, in the prior art, after the molten material is extruded from the annular die gap to form a bubble, even if the thickness of each point in the circumference is uneven, there is no effective remedial measure. Utility Model Content

[0006] The technical problem to be solved by the utility model is to provide a film bubble thickness fine-tuning device for a film blowing machine, which can achieve precise adjustment of the thickness of each local position on the circumference of the film bubble after the film bubble is extruded, so that the thickness of each point on the circumference of the film bubble becomes more uniform. The technical solution adopted is as follows:

[0007] A film bubble thickness fine-tuning device for a film blowing machine comprises a machine base, an air supply device and an air ring, the air supply device and the air ring are both mounted on the machine base, an annular air cavity is arranged inside the air ring, and the characteristic is that: the annular air cavity is divided into a plurality of air cavities along its circumference, and each air cavity is connected with the air outlet of the air supply device; the film bubble thickness fine-tuning device also comprises an air supply ring and a plurality of fine-tuning air control components, the plurality of fine-tuning air control components are arranged on the air ring along the circumference of the air ring, each fine-tuning air control component comprises a heating device and a heat expansion tube, the heating device is mounted in the air cavity, the outer wall of the heat expansion tube contacts and cooperates with the heating device, and the outer end opening of the heat expansion tube is connected with the air cavity; the air supply ring is arranged on the inner side of the air ring, and the air supply ring is provided with a plurality of air supply channels arranged along its circumference and running inwards and outwards, each air supply channel corresponds to each air cavity one by one, and the outer end opening of the air supply channel is connected with the inner end of the corresponding heat expansion tube.

[0008] The inner end and the outer end respectively refer to: taking the center of the blown film bubble as a reference, the end close to the center of the film bubble is the inner end, and the end far away from the center of the film bubble is the outer end.

[0009] In the above-mentioned fine-tuning wind control assembly, the power-on state of each heating device can be independently controlled. The heating device is used to conduct heat to the thermal expansion tube, so that the thermal expansion tube expands and contracts according to the temperature, thereby increasing or decreasing the inner diameter of the thermal expansion tube, thereby controlling the amount of air passing through the thermal expansion tube. When the above-mentioned film blowing machine is working, the air supply device conveys airflow to each air cavity of the air ring, and the airflow in each air cavity enters the corresponding air supply channel through the corresponding thermal expansion tube of the fine-tuning wind control assembly, and finally blows from the inner end opening of the air supply channel to the corresponding local part on the circumference of the film bubble to cool the local part. If the thickness of a certain local part on the circumference of the membrane bubble is thinner, it means that the cooling of the local part is insufficient, causing the membrane bubble to over-expand and become thinner in the local part. By controlling the heating device of the corresponding fine-tuning air flow control component, the inner diameter of the heat expansion tube will be enlarged, the air volume will be increased, and the local part of the membrane bubble will be cooled more promptly and become thicker; if the thickness of a certain local part on the circumference of the membrane bubble is thicker, by controlling the heating device of the corresponding fine-tuning air flow control component, the inner diameter of the heat expansion tube will be reduced, the air volume will be reduced, and the cooling amount of the local part will be reduced, so that the local part of the membrane bubble will become thinner, thereby making the thickness of each point on the circumference of the membrane bubble more uniform.

[0010] As a preferred embodiment of the utility model, the heating device is a heating tube, which is sleeved on the outside of the heat expansion tube and closely contacts and cooperates with it. Since the heat expansion tube is sleeved in the heating tube, the outer peripheral surface of the heat expansion tube is limited by the heating tube, and the heat expansion tube can only expand inward, thereby reducing the inner diameter of the heat expansion tube. When the heating is stopped, the inner diameter of the heat expansion tube expands accordingly. If the thickness of a local part of the circumference of the film bubble is thinner, it means that the cooling at this part is insufficient, causing the film bubble to expand excessively and become thinner at this part, then the heating of the heating tube is stopped, and the film is cooled, so that the tube wall of the heat expansion tube shrinks and becomes thinner, and the inner diameter becomes larger, so that the air volume becomes larger, so that the local part of the film bubble is cooled more timely and becomes thicker, thereby achieving a more uniform thickness of each point in the circumference of the film bubble; on the contrary, when the thickness of a local part of the circumference of the film bubble is thicker, the heating tube is controlled to heat, and the heat expansion tube is constrained by the external limit and expands inward, reducing the inner diameter, reducing the air volume, and making the local part of the film bubble thinner.

[0011] The opposite situation is that when the heat expansion tube is not compressed, it generally expands naturally due to heat and its inner diameter becomes larger. Therefore, the heating device can also use a general metal block, which only contacts but does not constrain the heat expansion tube. Therefore, when the heating device heats, the inner diameter of the heat expansion tube becomes larger, the air volume becomes larger, and the corresponding part of the membrane bubble becomes thicker. When the heating device stops heating, the inner diameter of the heat expansion tube becomes smaller, the air volume becomes smaller, and the corresponding part of the membrane bubble becomes thinner.

[0012] As a further preferred embodiment of the present invention, the heat expansion tube is a metal tube, and the heating tube is an electric heating tube. Thus, the metal tube can be heated by the heat generated by the electric heating tube, so that it increases in temperature and expands, thereby reducing the inner diameter. The electric heating tube can be an electric heating aluminum tube or an electric heating copper tube.

[0013] As a further preferred embodiment of the present invention, the metal tube is an aluminum tube or a copper tube. Since aluminum and copper have excellent thermal conductivity and a high expansion coefficient, when the temperature of the heating device changes, the aluminum tube and the copper tube can more sensitively expand and contract by a certain range, and the inner diameter of the aluminum tube and the copper tube can be adjusted by a certain range.

[0014] As a further preferred solution of the utility model, the outside of the heating tube is also covered with a heat-insulating sleeve, which can play a heat-insulating role and prevent the air ring from being damaged by heat due to direct contact with the heating tube.

[0015] As a preferred embodiment of the present invention, the air supply ring includes an upper annular plate, a lower annular plate and a plurality of partitions, the lower annular plate is arranged on the lower side of the upper annular plate, and the plurality of partitions are equidistantly arranged between the lower annular plate and the upper annular plate along the circumference of the air supply ring to form a plurality of the air supply channels.

[0016] As a further preferred embodiment of the utility model, the inner peripheral edge of the upper annular plate is provided with an upper arc-shaped flow guide extending inward and downward, and the upper arc-shaped flow guide is located on the inner side of the lower annular plate; the film bubble thickness fine-tuning device also includes an adjustable height position adjustment ring, the adjustment ring is arranged below the lower annular plate, and the top of the adjustment ring is provided with a lower arc-shaped flow guide, and the lower arc-shaped flow guide is located on the inner side of the lower annular plate and on the lower side of the upper arc-shaped flow guide. A flow guide channel is formed between the lower arc-shaped flow guide and the upper arc-shaped flow guide, and the flow guide channel is connected to the outer end opening of each of the gas replenishment channels. With this structure, a flow guide channel can be formed on the inner side of the gas replenishment ring, and the flow guide channel is connected to the outer end opening of each of the gas replenishment channels, and the inner end opening of the flow guide channel constitutes a flow guide port tilted downward; and the height position of the adjustment ring can be adjusted to change the spacing between the lower arc-shaped flow guide and the upper arc-shaped flow guide, thereby adjusting the gas flow rate coming out of the flow guide port, and realizing a small angle adjustment of the wind direction coming out of the flow guide port.

[0017] The adjusting mechanism for adjusting the height position of the adjusting ring can adopt an existing conventional adjusting mechanism such as a screw mechanism. As a preferred embodiment of the utility model, the adjusting mechanism for adjusting the height position of the adjusting ring includes a screw, an operating handle, a lifting seat, a guide rod and a guide sleeve. The screw can be rotatably mounted on the machine base and is in an up-and-down direction. The operating handle is fixedly mounted on the screw. The lifting seat is provided with a screw hole meshing with the screw. The guide rod is mounted on the machine base and is parallel to the screw. The guide sleeve is sleeved on the guide rod and connected to the lifting seat. The lower annular plate is mounted on the lifting seat. When in use, the operating handle can be manually rotated to rotate the screw, driving the lifting seat and the lower annular plate to move upward or downward along the guide rod, thereby changing the relative position and matching relationship between the lower arc-shaped guide portion and the upper arc-shaped guide portion.

[0018] As a preferred embodiment of the utility model, the air supply device includes a compressed air source and a plurality of air pipes, one end of each air pipe is connected to the air outlet of the compressed air source, and the other end of each air pipe is connected to the corresponding air cavity; each air pipe is installed with a proportional flow valve and a solenoid valve. Specifically, the compressed air source can be connected to the solenoid valve island (such as Festo solenoid valve island VTUG) through a proportional flow valve, and automatically adjusted and controlled by PLC after program setting. During operation, the compressed air source can pre-set the output air volume to the proportional flow valve, and then control the on and off of each air pipe through the solenoid valve island. Generally, it maintains a fully open state. When the air volume of a local part of the membrane bubble cannot meet the requirements by reducing the air volume through the thermal expansion tube, the air pipe is directly closed through the solenoid valve island.

[0019] As a further preferred embodiment of the present invention, the compressed air source is a gas storage tank.

[0020] Compared with the prior art, the utility model has the following advantages:

[0021] This film bubble thickness fine-tuning device arranges a plurality of fine-tuning wind control components on the circumference of the air ring. After the film bubble is extruded, the air volume blown toward the corresponding local parts on the circumference of the film bubble can be adjusted by each fine-tuning wind control component, thereby achieving precise adjustment of the thickness of each local position on the circumference of the film bubble, making the thickness of each point on the circumference of the film bubble more uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of a film bubble thickness fine adjustment device according to a preferred embodiment of the utility model.

[0023] Figure 2 yes Figure 1 Top view of the . DETAILED DESCRIPTION

[0024] like Figure 1 , Figure 2 As shown, the film bubble thickness fine adjustment device of the film blowing machine includes a machine base 1, an air supply device (not shown in the figure), an air ring 3, an air supply ring 4 and a plurality of fine-tuning air-control components 5. The air supply device and the air ring 3 are both installed on the machine base 1. An annular air cavity is provided inside the air ring 3. The annular air cavity is divided into a plurality of air cavities 30 along its circumference. Each air cavity 30 is connected to the air outlet of the air supply device. The plurality of fine-tuning air-control components 5 are arranged on the air ring 3 along its circumference. Each fine-tuning air-control component 5 includes a heating element. Tube 51 and heat expansion tube 52, the heating tube 51 is installed in the air cavity 30, the heating tube 51 is sleeved on the outside of the heat expansion tube 52 and closely contacts with it, and the outer end opening of the heat expansion tube 52 is communicated with the air cavity 30; the air supply ring 4 is arranged on the inner side of the wind ring 3, and the air supply ring 4 is provided with a plurality of air supply channels 40 arranged along its circumference and running inward and outward, each air supply channel 40 corresponds to each air cavity 30 one by one, and the outer end opening of the air supply channel 40 is communicated with the inner end of the corresponding heat expansion tube 52.

[0025] In this embodiment, the heat expansion tube 52 is an aluminum tube or a copper tube; the heating tube 51 is an electric heating tube (such as an electric heating aluminum tube or an electric heating copper tube). Thus, the aluminum tube or the copper tube can be heated by the heat of the electric heating tube, so that it increases in temperature and expands, thereby reducing the inner diameter. Since aluminum and copper have excellent thermal conductivity and a high expansion coefficient, when the temperature of the electric heating tube changes, the aluminum tube and the copper tube can more sensitively expand and contract by a certain range, and the inner diameter of the aluminum tube and the copper tube can be adjusted by a certain range.

[0026] In this embodiment, the outside of the heating tube 51 is also covered with a heat insulating sleeve 53. The heat insulating sleeve 53 can play a heat insulating role to prevent the air ring 3 from being damaged by heat due to direct contact with the heating tube 51.

[0027] In this embodiment, the air supplement ring 4 includes an upper annular plate 41, a lower annular plate 42 and a plurality of baffles (not shown in the figure), the lower annular plate 42 is arranged on the lower side of the upper annular plate 41, and the plurality of baffles are arranged equidistantly between the lower annular plate 42 and the upper annular plate 41 along the circumference of the air supplement ring 4 to form a plurality of air supplement channels 40; an upper arc-shaped guide portion 411 extending inwardly and downwardly is provided on the inner peripheral edge of the upper annular plate 41, and the upper arc-shaped guide portion 411 is located at the lower annular plate 42. The film bubble thickness fine adjustment device also includes an adjustable height ring 6, which is arranged below the lower annular plate 42, and a lower arc-shaped guide portion 61 is arranged on the top of the adjusting ring 6, which is located inside the lower annular plate 42 and below the upper arc-shaped guide portion 411, and a guide channel 60 is formed between the lower arc-shaped guide portion 61 and the upper arc-shaped guide portion 411, and the guide channel 60 is communicated with the outer end openings of each gas replenishment channel 40. With this structure, a guide channel 60 can be formed on the inner side of the gas replenishment ring 4, and the guide channel 60 is communicated with the outer end openings of each gas replenishment channel 40, and the inner end opening of the guide channel 60 constitutes a guide port tilted downward; and the height position of the adjusting ring 6 can be adjusted to change the spacing between the lower arc-shaped guide portion 61 and the upper arc-shaped guide portion 411, thereby adjusting the gas flow rate coming out of the guide port, and realizing a small angle adjustment of the wind direction coming out of the guide port.

[0028] In this embodiment, the gas supply device includes a gas storage tank and multiple gas supply pipes, one end of each gas supply pipe is connected to the gas outlet of the gas storage tank, and the other end of each gas supply pipe is connected to the corresponding air cavity 30; each gas supply pipe is installed with a proportional flow valve and a solenoid valve, the gas storage tank is connected to the solenoid valve island (such as Festo solenoid valve island VTUG) through the proportional flow valve, and is automatically adjusted and controlled by PLC after program setting. When working, the gas storage tank can pre-set the output air volume to the proportional flow valve, and then control the opening and closing of each gas supply pipe through the solenoid valve island. Generally, it maintains a full-open state. When the local part of the film bubble cannot meet the requirements by reducing the air volume through the thermal expansion tube 52, the gas supply pipe is directly closed through the solenoid valve island.

[0029] The following is a brief description of the working principle of the film bubble thickness fine adjustment device of this film blowing machine:

[0030] When the above-mentioned film blowing machine is working, the air supply device conveys airflow to each air cavity 30 of the air ring 3, and the airflow in each air cavity 30 enters the corresponding air supply channel 40 through the thermal expansion tube 52 of the corresponding fine-tuning air control component 5, and finally blows from the inner end opening of the air supply channel 40 to a corresponding local part on the circumference of the film bubble to cool the local part.

[0031] The power-on state of each heating tube 51 can be controlled independently. The heating tube 51 is used to conduct heat to the heat expansion tube 52, so that the heat expansion tube 52 will expand and contract according to the temperature. Since the heat expansion tube 52 is sleeved in the heating tube 51, the outer peripheral surface of the heat expansion tube 52 is limited by the heating tube 51. The heat expansion tube 52 can only expand inward, thereby reducing the inner diameter of the heat expansion tube 52. When the heating is stopped, the inner diameter of the heat expansion tube 52 is expanded accordingly, thereby controlling the amount of air passing through the heat expansion tube 52. If the thickness of a certain local part on the circumference of the membrane bubble is thinner, it means that the cooling of the local part is insufficient, causing the membrane bubble to over-expand and become thinner in the local part. Then, the heating tube 51 of the corresponding fine-tuning air-control component 5 is controlled to stop heating and cool, so that the tube wall of the heat expansion tube 52 shrinks and becomes thinner while the inner diameter becomes larger, the air volume becomes larger, and the local part of the membrane bubble is cooled more promptly and becomes thicker, thereby achieving the thickness of each point on the circumference of the membrane bubble becoming more uniform. On the contrary, if the thickness of a certain local part on the circumference of the membrane bubble is thicker, the heating tube 51 of the corresponding fine-tuning air-control component 5 is controlled to heat, and the heat expansion tube 52 is constrained by external restrictions and expands inward, reducing the inner diameter, reducing the air volume, and reducing the cooling amount of the local part, so that the local part of the membrane bubble becomes thinner, thereby achieving the thickness of each point on the circumference of the membrane bubble becoming more uniform.

[0032] In addition, it should be noted that the names of the various parts of the specific embodiments described in this specification may be different, and any equivalent or simple changes made based on the structure, features and principles described in the utility model patent concept are included in the protection scope of the utility model patent. The technical personnel of the technical field to which the utility model belongs can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the utility model or exceed the scope defined by the claims, they should all fall within the protection scope of the utility model.

Claims

1. A film bubble thickness fine adjustment device for a film blowing machine, comprising a machine base, an air supply device and an air ring, wherein the air supply device and the air ring are both mounted on the machine base, and an annular air cavity is provided inside the air ring, characterized in that: The annular wind cavity is divided into a plurality of air cavities along its circumference, and each air cavity is connected to the air outlet of the air supply device; the membrane bubble thickness fine-tuning device also includes an air supply ring and a plurality of fine-tuning air control components, and the plurality of fine-tuning air control components are arranged on the wind ring along the circumference of the wind ring, and each fine-tuning air control component includes a heating device and a heat expansion tube, and the heating device is installed in the air cavity, and the outer wall of the heat expansion tube contacts and cooperates with the heating device, and the outer end opening of the heat expansion tube is connected to the air cavity; the air supply ring is arranged on the inner side of the wind ring, and the air supply ring is provided with a plurality of air supply channels arranged along its circumference and running inward and outward, each air supply channel corresponds to each air cavity one by one, and the outer end opening of the air supply channel is connected to the inner end of the corresponding heat expansion tube.

2. The film bubble thickness fine adjustment device of the film blowing machine according to claim 1, characterized in that: The heating device is a heating tube, which is sleeved outside the thermal expansion tube and is in close contact with it.

3. The film bubble thickness fine adjustment device of the film blowing machine according to claim 2, characterized in that: The thermal expansion tube is a metal tube, and the heating tube is an electric heating tube.

4. The film bubble thickness fine adjustment device of the film blowing machine according to claim 3, characterized in that: The metal tube is an aluminum tube or a copper tube.

5. The film bubble thickness fine adjustment device of the film blowing machine according to claim 2, characterized in that: The outside of the heating tube is also covered with a heat insulating sleeve.

6. A film bubble thickness fine adjustment device for a film blowing machine according to any one of claims 1 to 5, characterized in that: The air supplement ring comprises an upper annular plate, a lower annular plate and a plurality of partitions, wherein the lower annular plate is arranged at the lower side of the upper annular plate, and the plurality of partitions are arranged equidistantly between the lower annular plate and the upper annular plate along the circumference of the air supplement ring to form a plurality of the air supplement channels.

7. The film bubble thickness fine adjustment device of the film blowing machine according to claim 6, characterized in that: An upper arc-shaped guide portion extending inward and downward is provided on the inner peripheral edge of the upper annular plate, and the upper arc-shaped guide portion is located on the inner side of the lower annular plate; the membrane bubble thickness fine-tuning device also includes an adjustment ring with adjustable height position, the adjustment ring is arranged below the lower annular plate, and a lower arc-shaped guide portion is provided on the top of the adjustment ring, the lower arc-shaped guide portion is located on the inner side of the lower annular plate and on the lower side of the upper arc-shaped guide portion, a guide channel is formed between the lower arc-shaped guide portion and the upper arc-shaped guide portion, and the guide channel is connected to the outer end opening of each of the air supply channels.

8. The film bubble thickness fine adjustment device of the film blowing machine according to claim 6, characterized in that: The air supply device includes a compressed air source and multiple air pipes, one end of each air pipe is connected to the air outlet of the compressed air source, and the other end of each air pipe is connected to the corresponding air cavity; a proportional flow valve and a solenoid valve are installed on each air pipe.

9. The film bubble thickness fine adjustment device of the film blowing machine according to claim 8, characterized in that: The compressed gas source adopts a gas storage tank.

Images