Dual-state temperature control structure and UPVC special machine

Abstract

The application relates to the technical field of injection molding machines, and discloses a double-state temperature control structure and a UPVC special machine. The application comprises a cladding assembly, a fan and a dynamic switching assembly. A heat preservation cover is cladded on the outside of a glue melting cylinder to form an annular chamber, the flow cross section of the chamber is gradually reduced from bottom to top, and the outlet of the flow channel is low. A magnetic attraction frame is fixedly connected in the bottom inflow channel and is hinged with a swing plate. When radiating heat, the fan airflow pushes away the swing plate, the airflow accelerates through the contraction chamber, circumferential balanced heat dissipation is realized, and material scorching or cold setting is avoided; when keeping warm, the fan is closed, the swing plate is reset and closed by gravity and magnetic force, and the contraction chamber is matched to inhibit heat convection. The application realizes flexible switching of heat dissipation and heat preservation, effectively improves the injection molding quality and reduces heat loss.

Description

Technical Field

[0001] This invention relates to the field of injection molding machine technology, and in particular to a dual-state temperature control structure and a dedicated machine for UPVC. Background Technology

[0002] When processing certain heat-sensitive plastics (such as UPVC, i.e., rigid polyvinyl chloride), injection molding machines have extremely stringent requirements for the temperature control of the melt cylinder. The temperature cannot be too high or too low because UPVC material has a narrow processing temperature range. Excessive temperature can easily lead to material degradation, yellowing, or even scorching; excessively low temperature can result in poor plasticization or cold solidification. The temperature of the melt cylinder is affected not only by the heating coils but also by the shear heat generated when the material inside the cylinder is forcefully squeezed and agitated, often leading to localized overheating. Therefore, current UPVC-specific machines typically install an insulation cover on the outside of the melt cylinder to slow down heat dissipation and prevent the processing temperature from dropping too quickly, maintaining a stable temperature range. Simultaneously, since the melt cylinder continuously generates heat during injection molding, when the thermocouple on the melt cylinder detects a temperature exceeding the set upper limit, a cooling fan outside the insulation cover is activated. This airflow removes excess heat from the insulation cover, achieving precise temperature control and ensuring injection molding quality.

[0003] The existing temperature control devices for melt cylinders have the following technical defects: (1) It is difficult to balance heat dissipation and heat preservation: conventional heat preservation covers can only rely on external fans to blow air directly to dissipate heat. However, when the fans are turned off and heat preservation is required, the hot air inside the heat preservation cover will overflow from the air duct due to natural convection, and cannot form an effective static air insulation layer, resulting in heat loss too quickly and increasing the energy consumption of the injection molding machine; (2) Poor heat dissipation uniformity: the airflow of the existing device usually blows directly from a single inlet to the melt cylinder, resulting in excessive heat dissipation near the air inlet, while insufficient heat dissipation at the locations far from the air inlet or at both ends of the axis; this uneven temperature distribution in the circumferential or axial direction may cause poor plasticization or scorching of local materials in the melt cylinder, affecting the final injection molding quality. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, one objective of this invention is to propose a dual-state temperature control structure. Another objective of this invention is to provide a UPVC-specific machine that includes the above-mentioned dual-state temperature control structure, so as to solve the problems of difficulty in balancing heat dissipation and heat preservation and poor heat dissipation uniformity in the prior art.

[0005] A dual-state temperature control structure includes: a covering component, a fan, and a dynamic switching component. The covering component includes an insulation cover that covers the outside of the melting cylinder of an injection molding machine, with a gap between the insulation cover and the outer wall of the melting cylinder. The insulation cover and the melting cylinder together form an annular chamber. The insulation cover is also provided with an inflow channel and an outflow channel. The air outlet of the fan is connected to the bottom of the annular chamber via the inflow channel, and the outflow channel is connected to the top of the annular chamber. The dynamic switching component includes: a magnetic frame and at least one swing plate. The magnetic frame is fixedly connected to the inflow channel, and one side of the swing plate is hinged to the inflow channel. When the swing plate is pushed by the airflow, it can rotate around the hinged side to open the inflow channel. When the swing plate is not pushed by the airflow, it falls back under its own weight and is magnetically attracted to the magnetic frame to close the inflow channel. In the interval from the inflow channel to the outflow channel, the cross-sectional area of ​​the annular chamber gradually decreases. The end of the outflow channel is lower than the other parts of the outflow channel.

[0006] Preferably, the above-mentioned dual-state temperature control structure further includes a flow equalization component, which includes a flow stabilizer shroud. The end of the inflow channel is connected to the inside of the flow stabilizer shroud. An axial through groove is opened on the upper side of the flow stabilizer shroud. The axial through groove extends along the axial direction of the melt cylinder. The inside of the flow stabilizer shroud is connected to the annular chamber through the axial through groove, which is located below the melt cylinder.

[0007] Preferably, the flow equalization assembly further includes two guide plates, both of which are fixedly installed inside the flow stabilizer. The two guide plates are located above the end of the inflow channel, and each guide plate has an inner arc surface and an outer arc surface. A flow expansion channel is formed between the two inner arc surfaces, and the flow expansion channel gradually widens from bottom to top. The two guide plates are used together to cut the airflow at the end of the inflow channel into three parts, so that one part of the airflow flows along the flow expansion channel. The two outer arc surfaces guide the remaining two parts of the airflow, so that the two parts of the airflow diffuse axially towards both ends of the flow stabilizer.

[0008] Preferably, the dual-state temperature control structure further includes a heat-conducting ring, which is fixed and attached to the outside of the melt cylinder. The heat-conducting ring has several arc-shaped grooves extending circumferentially. A flow divider is fixed to the side of the heat-conducting ring near the axial through groove. The flow divider has two arc-shaped inclined surfaces to cut the airflow into two branches, which flow to both sides along the annular cavity respectively.

[0009] Preferably, the end of the inflow channel is directly opposite the middle of the axial channel, and in the axial direction of the melt cylinder, the middle of the axial channel gradually widens towards both ends of the axial channel.

[0010] Preferably, the heat insulation cover has two outflow channels; the flow equalization assembly also includes a lower guide strip and an upper guide strip; the lower guide strip protrudes radially inward from the heat insulation cover, and the upper guide strip protrudes radially outward from the heat conduction ring. The upper guide strip is spaced above the lower guide strip. The lower guide strip has two first guide arc surfaces to guide the two branches in the annular cavity to flow upward respectively; the upper guide strip has two second guide arc surfaces to guide the two branches to flow into the outflow channels respectively.

[0011] Preferably, there are two swing plates, both of which are magnetically attached to the magnetic frame. The side of the two swing plates that is far apart from each other is the hinge side. Two elastic limiting pads are fixed in the inflow channel, and the elastic limiting pads correspond one-to-one with the swing plates. The elastic limiting pads are located in the rotation path of the swing plates. When the swing plates are pushed by the airflow, the swing plates rotate and abut against the elastic limiting pads.

[0012] Preferably, the heat insulation cover is provided with annular baffles at both ends, the outer side of the annular baffles is in close contact and sealed with the heat insulation cover, and the inner side of the annular baffles is in close contact and sealed with the melt cylinder.

[0013] Preferably, the heat insulation cover is divided into an upper outer cover, an upper inner cover, a lower outer cover, and a lower inner cover; the upper outer cover and the upper inner cover are fixedly connected, and there is a certain gap between the inner wall of the upper outer cover and the outer wall of the upper inner cover, with the outflow channel located between the upper outer cover and the upper inner cover; the lower outer cover and the lower inner cover are fixedly connected, and there is a certain gap between the inner wall of the lower outer cover and the outer wall of the lower inner cover; one side of the upper outer cover and one side of the lower outer cover are hinged, and the other side of the upper outer cover and the other side of the lower outer cover are connected by a buckle.

[0014] A UPVC-specific machine includes a main body, a melting cylinder, and the aforementioned dual-state temperature control structure.

[0015] Beneficial effects: (1) Better compatibility between heat dissipation and heat preservation: When heat dissipation is required for the melt cylinder, the electrical control components control the fan to start. Along the airflow path, the cross-sectional area of ​​the annular chamber gradually decreases, forcing the airflow speed to increase. Furthermore, the airflow gradually absorbs heat and its temperature rises during flow. These two factors work together to promote a more balanced heat dissipation effect in the circumferential direction of the melt cylinder, thus preventing localized scorching or condensation of the material. When heat preservation of the melt cylinder is required, the electronic control unit shuts down the fan, and the oscillating plate resets under its own gravity and the magnetic attraction of the magnetic frame, closing the inflow channel. Combined with the gradually contracting structure of the annular chamber from bottom to top, and the fact that the end of the outflow channel is lower than other parts of the outflow channel, the upward surge of hot air within the annular chamber is suppressed, reducing air convection and forming a stable air layer for efficient heat preservation of the melt cylinder. Therefore, by controlling the start and stop of the fan, heat dissipation or heat preservation of the melt cylinder can be achieved. This allows for more uniform heat dissipation of the material within the melt cylinder, improving injection molding results, and also efficiently preserves the melt cylinder, reducing heat waste.

[0016] (2) More uniform heat dissipation: The air is filled with air by the obstruction of the airflow by the flow stabilizer, and the internal mirror-symmetrical guide plate cuts the airflow into three parts and diffuses it to both ends. The axial through groove that gradually widens from the top to both ends makes the airflow in the annular cavity more uniformly distributed in the axial direction. The arc groove on the heat conduction ring is used to increase the airflow contact area and guide the airflow to flow in close contact to improve the heat dissipation effect. At the same time, the airflow is cut into two branches by the flow divider, making the airflow to both sides of the annular cavity more balanced. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the first three-dimensional structure of the present invention.

[0018] Figure 2 This is a schematic diagram of the second three-dimensional structure of the present invention.

[0019] Figure 3 This is a cross-sectional three-dimensional structural diagram of the present invention.

[0020] Figure 4 For the present invention Figure 3 A magnified three-dimensional structural diagram at point A in the middle.

[0021] Figure 5 This is a schematic diagram of the airflow direction and the first cross-sectional structure of the present invention.

[0022] Figure 6 This is a cross-sectional three-dimensional structural diagram of the melt cylinder, coating component and fan of the present invention.

[0023] Figure 7 This is a schematic diagram of the airflow direction and a second cross-sectional three-dimensional structure of the present invention.

[0024] Figure 8 This is a schematic diagram of the split three-dimensional structure of the present invention.

[0025] Figure 9 This is a three-dimensional structural diagram showing the heating coil, dynamic switching component, flow equalization component, and heat-conducting ring of the present invention.

[0026] Figure 10 This is a three-dimensional structural diagram of the magnetic frame and magnetic strip of the present invention.

[0027] Specific reference numerals in the attached drawings: 10, Main body; 20, Melting cylinder; 21, Heating coil; 30, Covering assembly; 31, Insulation cover; 311, Upper outer cover; 312, Upper inner cover; 313, Lower outer cover; 314, Lower inner cover; 32, Inflow channel; 33, Outflow channel; 34, Annular baffle; 35, Buckle; 40, Annular chamber; 50, Fan; 51, Air outlet; 60, Dynamic switching assembly; 61, Magnetic frame; 611. Magnetic suction strip; 62, swing plate; 621, hinged side; 63, elastic limiting pad; 70, flow equalization assembly; 71, flow stabilizer; 711, axial through groove; 72, guide plate; 721, inner arc surface; 722, outer arc surface; 73, flow expansion channel; 74, lower guide strip; 741, first guide arc surface; 75, upper guide strip; 751, second guide arc surface; 80, heat conduction ring; 81, arc groove; 82, flow divider; 821, arc slope. Detailed Implementation

[0028] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0029] In the description of this invention, it should be understood that the terms "center", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0031] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0032] A dual-state temperature control structure, such as Figures 1-10 As shown, the system includes: a covering assembly 30, a fan 50, and a dynamic switching assembly 60. The covering assembly 30 includes a heat insulation cover 31, which covers the outside of the injection molding machine's melt cylinder 20. Multiple dual-state temperature control structures are installed on the outer wall of the melt cylinder 20, arranged sequentially along the axial direction of the melt cylinder 20 to control the temperature of the melt cylinder 20 in segments. The melt cylinder 20 includes multiple heating coils 21, arranged sequentially along the axial direction of the melt cylinder 20. The heating elements are arranged to heat the material inside the melting cylinder 20 in sections. A gap is left between the heat insulation cover 31 and the outer wall of the melting cylinder 20. The heat insulation cover 31 and the melting cylinder 20 together form an annular chamber 40. Each annular chamber 40 contains at least one heating coil 21. The heat insulation cover 31 is also provided with an inflow channel 32 and an outflow channel 33. The air outlet 51 of the blower 50 is connected to the bottom of the annular chamber 40 through the inflow channel 32, and the outflow channel 33 is connected to the top of the annular chamber 40.

[0033] like Figure 4 , Figure 5 and Figure 9As shown, the dynamic switching component 60 includes: a magnetic frame 61 and at least one swing plate 62; the magnetic frame 61 is fixedly connected to the inflow channel 32, and a magnetic strip 611 is fixedly connected to the magnetic frame 61; one side of the swing plate 62 is hinged to the inflow channel 32 by a pin; the magnetic frame 61 is a hollow frame, which has little impact on the airflow in the inflow channel 32; when the swing plate 62 is pushed by the airflow, it can rotate around the hinge side 621 of the swing plate 62 to open the inflow channel 32; when the swing plate 62 is not pushed by the airflow, the swing plate 62 falls back under its own gravity and is magnetically attracted to the magnetic frame 61 to close the inflow channel 32. Channel 32; the swing plate 62 is made of a magnetically attractive material. The magnetic frame 61 magnetically attracts the swing plate 62 through the magnetic strip 611, so that the swing plate 62 does not need to rely too much on its own gravity and can fit more tightly with the magnetic frame 61, thereby closing the inflow channel 32 more tightly, making the swing plate 62 thinner and lighter; throughout the entire rotation stroke of the swing plate 62, its center of gravity always remains on the same side of the hinge axis; it should be noted that the dynamic switching component 60 is set at the end of the inflow channel 32 away from the annular chamber 40, so as to avoid the high temperature of the melt cylinder 20 affecting the rotational stability of the swing plate 62.

[0034] like Figure 7 As shown, within the interval from the inflow channel 32 to the outflow channel 33, the area of ​​the flow cross section of the annular chamber 40 gradually decreases; specifically, within the interval from the inflow channel 32 to the outflow channel 33, the radial width of the annular chamber 40 gradually decreases, but in the portions corresponding to the wiring terminals of the heating coil 21 and the snap-fit ​​terminals 35, the radial width of the annular chamber 40 is appropriately increased to ensure sufficient flow cross section for smooth airflow; more specifically, in the annular chamber 40, the radial width near the inflow channel 32 is 3 cm, and the radial width near the outflow channel 33 is 1.5 cm; the end of the outflow channel 33 is lower than the other portions of the outflow channel 33.

[0035] When heat dissipation is required for the melt cylinder 20, the thermocouple on the corresponding section of the melt cylinder 20 detects that the temperature exceeds the set upper temperature limit. The electronic control component controls the fan 50 to start. The fan 50 drives the airflow to flow sequentially through the air outlet 51, the inflow channel 32, the annular chamber 40, and the outflow channel 33, and finally flows out into the air through the outflow channel 33. When the airflow passes through the annular chamber 40, the airflow dissipates heat from the melt cylinder 20. Along the airflow path, the cross-sectional area of ​​the annular chamber 40 gradually decreases, forcing the airflow speed to increase. During the airflow, the airflow gradually absorbs heat and the temperature rises. Thus, from the inflow channel 32 to the outflow channel 33, the airflow temperature gradually rises, and the airflow speed gradually increases. The two work together to make the heat dissipation effect of the melt cylinder 20 more balanced in the circumferential direction, so that the material in the melt cylinder 20 can be dissipated more evenly. This avoids insufficient or excessive heat dissipation in some areas of the melt cylinder 20, thereby avoiding local scorching or caking of the material and improving the injection molding effect.

[0036] When the airflow passes through the inflow channel 32, the airflow pushes the swing plate 62 to overcome the magnetic attraction of the magnetic frame 61, and then rotates around the hinge side 621. Since the swing plate 62 is relatively thin, the airflow needs to overcome the weight of the swing plate 62. Moreover, compared with the connection through the spring, the resistance to pushing the swing plate 62 to rotate will not gradually increase, but will decrease rapidly after overcoming the magnetic attraction. This allows the swing plate 62 to have a sufficient rotation range even when the wind force is small, so that the inflow channel 32 has a sufficiently large flow area, allowing the airflow to pass through the inflow channel 32 more smoothly.

[0037] When heat preservation of the melt cylinder 20 is required, the thermocouple on the corresponding section of the melt cylinder 20 detects that the temperature has returned to the set temperature range. The fan 50 is shut off by the electronic control component, and the swing plate 62 resets under the combined action of its own gravity and the magnetic attraction of the magnetic frame 61, thereby closing the inflow channel 32 and blocking air from flowing into the annular chamber 40. The gradually contracting structure of the annular chamber 40 from bottom to top gradually increases the resistance to the upward flow of air. In addition, the air flows through the end of the outflow channel 33, which is lower than other parts of the outflow channel 33, combined with the fact that the density of hot air is lower than that of other parts of the outflow channel 33. The characteristic of cold and hot air constantly rising causes the air in the annular chamber 40 to be blocked by the outflow channel 33, thus suppressing the rising of hot air in the annular chamber 40. Through the aforementioned closed inflow channel 32, the gradually contracting structure of the annular chamber 40 from bottom to top, and the fact that the end of the outflow channel 33 is lower than other parts of the outflow channel 33, the thermal convection of air in the annular chamber 40 is reduced, forming a stable air layer. This air layer reduces the heat transfer efficiency of the melt cylinder 20 to the outside world, thereby efficiently insulating the melt cylinder 20 and reducing heat waste.

[0038] Therefore, by controlling the start and stop of the fan 50, the melting cylinder 20 can be cooled or kept warm; this allows the material in the melting cylinder 20 to be cooled more evenly, improving the injection molding effect, and also efficiently keeps the melting cylinder 20 warm, reducing heat waste.

[0039] More preferably, such as Figure 5 , Figure 7 , Figure 8 and Figure 9 As shown, the above-mentioned dual-state temperature control structure also includes a flow equalization component 70. The flow equalization component 70 includes a flow stabilizer 71, which is fixed inside the insulation cover 31. The end of the inflow channel 32 is connected to the inside of the flow stabilizer 71. An axial through groove 711 is opened on the upper side of the flow stabilizer 71. The axial through groove 711 extends along the axial direction of the melt cylinder 20. The inside of the flow stabilizer 71 is connected to the annular chamber 40 through the axial through groove 711. The axial through groove 711 is located below the melt cylinder 20.

[0040] When heat dissipation is required for the melt cylinder 20, airflow flows into the interior of the flow stabilizer 71 through the inflow channel 32, and then flows upward into the annular chamber 40 through the axial through groove 711 on the flow stabilizer 71, so that the airflow contacts the melt cylinder 20. Through the obstruction of the airflow by the flow stabilizer 71, air is filled into the flow stabilizer 71, and then the air in the flow stabilizer 71 is discharged upward through the axial through groove 711, so that the airflow flowing into the annular chamber 40 is more evenly distributed in the axial direction, thereby making the heat dissipation effect of the melt cylinder 20 more balanced in the axial direction, and further improving the uniformity of the heat dissipation effect of the material in the melt cylinder 20.

[0041] More preferably, such as Figure 4 , Figure 5 , Figure 7 , Figure 8 , Figure 9 and Figure 10 As shown, the flow equalization assembly 70 also includes two guide plates 72, both of which are fixedly installed inside the flow stabilizer 71. The two guide plates 72 are located above the end of the inflow channel 32 and are arranged in a mirror symmetrical manner. Each guide plate 72 is provided with an inner arc surface 721 and an outer arc surface 722. A flow expansion channel 73 is formed between the two inner arc surfaces 721, and the flow expansion channel 73 gradually widens from bottom to top. The outer arc surface 722 gradually bends axially from bottom to top. The two guide plates 72 are used together to cut the airflow at the end of the inflow channel 32 into three parts, so that one part of the airflow flows along the flow expansion channel 73. The two outer arc surfaces 722 guide the remaining two parts of the airflow, so that the two parts of the airflow diffuse axially towards both ends of the flow stabilizer 71.

[0042] When heat dissipation is required for the melt cylinder 20, airflow flows into the interior of the flow stabilizer 71 through the inflow channel 32. The airflow comes into contact with the two guide plates 72, which together cut the airflow at the end of the inflow channel 32 into three parts. One part of the airflow flows along the expansion channel 73, and during the flow, the airflow flows along the inner arc surface 721, so that the side of the guide plate 72 away from the inflow channel 32 can obtain sufficient airflow. The two outer arc surfaces 722 guide the remaining two parts of the airflow, so that the two parts of the airflow diffuse axially towards both ends of the flow stabilizer 71, so that both ends of the flow stabilizer 71 can also obtain sufficient airflow. This makes the airflow in the flow stabilizer 71 more evenly distributed in the axial direction, so that the axial through groove 711 on the flow stabilizer 71 can more evenly channel the airflow into the annular chamber 40, thereby further making the heat dissipation effect of the melt cylinder 20 in the axial direction more balanced.

[0043] More preferably, such as Figure 7 , Figure 8 and Figure 9 As shown, the dual-state temperature control structure also includes a heat-conducting ring 80, which is fixedly attached to and adhered to the outer side of the heating coil 21 of the melt cylinder 20. The heat-conducting ring 80 is composed of two arc plates. Under the condition that there is no interference, the heat-conducting ring 80 can also be a structure of a whole ring. Several arc-shaped grooves 81 extending circumferentially are opened on the heat-conducting ring 80. The arc-shaped grooves 81 are used to increase the contact area between the airflow and the heat-conducting ring 80, and can guide the airflow to flow along the arc-shaped grooves 81 to improve the heat dissipation effect. A flow divider 82 is fixedly attached to the side of the heat-conducting ring 80 near the axial through groove 711. The flow divider 82 is provided with two arc-shaped inclined surfaces 821 to cut the airflow into two branches. These two branches flow along the annular chamber 40 to both sides, so that the airflow in the annular chamber 40 to both sides is more balanced.

[0044] More preferably, such as Figure 5 and Figure 9 As shown, the air pressure is higher in the part of the flow stabilizer 71 closer to the inflow channel 32, while the air pressure is lower in the part of the flow stabilizer 71 further away from the inflow channel 32. In order to make the air volume distribution in the axial direction of the axial channel 711 more balanced, the end of the inflow channel 32 is directly opposite the middle of the axial channel 711. In the axial direction of the melt cylinder 20, the middle of the axial channel 711 gradually widens towards both ends of the axial channel 711, so that both ends of the axial channel 711 can obtain more sufficient air volume, thereby further making the heat dissipation effect of the melt cylinder 20 in the axial direction more balanced.

[0045] More preferably, such as Figure 7As shown, in order to facilitate smoother airflow discharge within the annular chamber 40, two outflow channels 33 are provided on the insulation cover 31. The flow equalization assembly 70 also includes a lower guide strip 74 and an upper guide strip 75. The upper guide strip 75 protrudes radially outward from the heat-conducting ring 80 and is fixed to the top of the heat-conducting ring 80. The lower guide strip 74 is fixed to the insulation cover 31 and protrudes radially inward from the insulation cover 31. The upper guide strip 75 is spaced above the lower guide strip 74 to prevent direct heat transfer between the upper and lower guide strips 75. The lower guide strip 74 has two first guide arc surfaces 741 to guide the two branches within the annular chamber 40 upward. The upper guide strip 75 has two second guide arc surfaces 751 to guide the two branches into the outflow channel 33 and then discharge them to the outside of the insulation cover 31 through the outflow channel 33.

[0046] More preferably, such as Figure 4 and Figure 9 As shown, there are two swing plates 62, both of which are magnetically attached to the magnetic frame 61. The side of the two swing plates 62 that is far apart from each other is the hinge side 621. Two elastic limiting pads 63 are fixedly installed in the inflow channel 32, and the elastic limiting pads 63 correspond one-to-one with the swing plates 62. The elastic limiting pads 63 are located within the rotation path of the swing plates 62. When the swing plates 62 are pushed by the airflow, the swing plates 62 rotate and come into contact with the elastic limiting pads 63. The airflow push force on the swing plates 62 is transmitted to the elastic limiting pads 63, and the elastic limiting pads 63 are subjected to force. The elastic deformation allows the swing plate 62 to rotate in the opposite direction and reset when the fan 50 stops supplying airflow to the inflow channel 32. After long-term operation, as dirt accumulates on the inflow channel 32 and the swing plate 62, the weight of the swing plate 62 alone may not be able to overcome the rotational resistance, resulting in failure to reset. In order to improve the stability of this dual-state temperature control structure, the elastic limit pad 63 can push the swing plate 62 to ensure that the swing plate 62 can overcome the rotational resistance and reset. The elastic limit pad 63 is a stainless steel spring sheet.

[0047] More preferably, such as Figure 2 , Figure 6 and Figure 8 As shown, in order to ensure that the heat insulation cover 31 has sufficient heat insulation performance, annular baffles 34 are provided at both ends of the heat insulation cover 31. The outer side of the annular baffle 34 is in close contact with the heat insulation cover 31 and sealed. The inner side of the annular baffle 34 is in close contact with the melting cylinder 20 through heat insulation material. The annular baffle 34 is divided into upper and lower parts for easy disassembly.

[0048] More preferably, such as Figure 6 and Figure 8As shown, the insulation cover 31 is divided into an upper outer cover 311, an upper inner cover 312, a lower outer cover 313, and a lower inner cover 314. The upper outer cover 311 and the upper inner cover 312 are fixedly connected, and there is a certain gap between the inner wall of the upper outer cover 311 and the outer wall of the upper inner cover 312. The outflow channel 33 is located between the upper outer cover 311 and the upper inner cover 312. A through hole is opened on the upper outer cover 311, and the end of the outflow channel 33 is connected to the outside of the insulation cover 31 through the through hole. The lower outer cover 313 and the lower inner cover 314 are fixedly connected, and the inner wall of the lower outer cover 313 is connected to the outer wall of the lower inner cover 314. There is a certain gap between the outer walls of the cover 314; one side of the upper outer cover 311 and one side of the lower outer cover 313 are hinged, and the other side of the upper outer cover 311 and the other side of the lower outer cover 313 are connected by a buckle 35; the upper half of the annular baffle 34 is fixed to the upper outer cover 311, and the lower half of the annular baffle 34 is fixed to the lower outer cover 313; the contact parts of the upper inner cover 312 and the lower inner cover 314 are connected by a concave-convex fitting, and the contact parts of the upper outer cover 311 and the lower outer cover 313 are also connected by a concave-convex fitting to improve the sealing performance of the heat insulation cover 31.

[0049] This invention also discloses a special machine for UPVC, such as Figures 1-4 As shown, the system includes a main body 10, a melting cylinder 20, and the aforementioned dual-state temperature control structure. The melting cylinder 20 is equipped with multiple heating coils 21, and multiple dual-state temperature control structures are mounted axially on the melting cylinder 20. Any injection molding machine employing the same or substantially the same dual-state temperature control structure should be within the scope of protection of this invention.

[0050] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A dual-state temperature control structure, characterized in that, include: Encasing components, fans, and dynamic switching components; The covering assembly includes a heat insulation cover that covers the outside of the injection molding machine's melting cylinder. A gap is left between the heat insulation cover and the outer wall of the melting cylinder. The heat insulation cover and the melting cylinder together form an annular chamber. The heat insulation cover is also provided with an inflow channel and an outflow channel. The air outlet of the fan is connected to the bottom of the annular chamber through the inflow channel, and the outflow channel is connected to the top of the annular chamber. The dynamic switching component includes: a magnetic frame and at least one swing plate; the magnetic frame is fixedly connected to the inflow channel, and one side of the swing plate is hinged to the inflow channel; when the swing plate is pushed by the airflow, it can rotate around the hinged side of the swing plate to open the inflow channel; when the swing plate is not pushed by the airflow, the swing plate falls back under its own gravity and is magnetically attracted to the magnetic frame to close the inflow channel. Within the interval from the inflow channel to the outflow channel, the area of ​​the flow cross section of the annular chamber gradually decreases; the end of the outflow channel is lower than the other parts of the outflow channel.

2. The dual-state temperature control structure according to claim 1, characterized in that, The dual-state temperature control structure also includes a flow equalization component, which includes a flow stabilizer. The end of the inflow channel is connected to the inside of the flow stabilizer. An axial through groove is opened on the upper side of the flow stabilizer. The axial through groove extends along the axial direction of the melt cylinder. The inside of the flow stabilizer is connected to the annular chamber through the axial through groove. The axial through groove is located below the melt cylinder.

3. The dual-state temperature control structure according to claim 2, characterized in that, The flow equalization assembly also includes two guide plates, both of which are fixedly disposed inside the flow stabilizer and located above the end of the inflow channel. Each guide plate has an inner arc surface and an outer arc surface. A flow expansion channel is formed between the two inner arc surfaces, and the flow expansion channel gradually widens from bottom to top. The two guide plates work together to cut the airflow at the end of the inflow channel into three parts, so that one part of the airflow flows along the flow expansion channel. The two outer arc surfaces guide the remaining two parts of the airflow, so that the two parts of the airflow diffuse axially towards both ends of the flow stabilizer.

4. The dual-state temperature control structure according to claim 3, characterized in that, The dual-state temperature control structure also includes a heat-conducting ring, which is fixed and attached to the outside of the melt cylinder. The heat-conducting ring has several arc-shaped grooves extending circumferentially. A flow divider is fixed to the side of the heat-conducting ring near the axial through groove. The flow divider has two arc-shaped inclined surfaces to cut the airflow into two branches, which flow along the annular chamber to both sides.

5. The dual-state temperature control structure according to claim 3, characterized in that, The end of the inflow channel is directly opposite the middle of the axial channel. In the axial direction of the melt cylinder, the middle of the axial channel gradually widens towards both ends of the axial channel.

6. The dual-state temperature control structure according to claim 4, characterized in that, The heat insulation cover has two outflow channels; the flow equalization component also includes a lower guide strip and an upper guide strip; the lower guide strip protrudes radially inward from the heat insulation cover, and the upper guide strip protrudes radially outward from the heat-conducting ring. The upper guide strip is spaced above the lower guide strip. The lower guide strip has two first guide arc surfaces to guide the two branches in the annular cavity to flow upward respectively; the upper guide strip has two second guide arc surfaces to guide the two branches to flow into the outflow channels respectively.

7. The dual-state temperature control structure according to claim 1, characterized in that, There are two swing plates, both of which are magnetically attached to the magnetic frame. The side of the two swing plates that is far apart from each other is the hinge side. Two elastic limiting pads are fixed in the inflow channel, and the elastic limiting pads correspond one-to-one with the swing plates. The elastic limiting pads are located in the rotation path of the swing plates. When the swing plates are pushed by the airflow, the swing plates rotate and abut against the elastic limiting pads.

8. The dual-state temperature control structure according to claim 1, characterized in that, The heat insulation cover is provided with annular baffles at both ends. The outer side of the annular baffle is in close contact with the heat insulation cover and sealed, and the inner side of the annular baffle is in close contact with the molten glue cylinder.

9. The dual-state temperature control structure according to claim 1, characterized in that, The insulation cover is divided into an upper outer cover, an upper inner cover, a lower outer cover, and a lower inner cover. The upper outer cover and the upper inner cover are fixedly connected, and there is a certain gap between the inner wall of the upper outer cover and the outer wall of the upper inner cover. The outflow channel is located between the upper outer cover and the upper inner cover. The lower outer cover and the lower inner cover are fixedly connected, and there is a certain gap between the inner wall of the lower outer cover and the outer wall of the lower inner cover. One side of the upper outer cover and one side of the lower outer cover are hinged together, and the other side of the upper outer cover and the other side of the lower outer cover are connected by a buckle.

10. A special machine for UPVC, characterized in that, It includes the main body, the melting cylinder, and the dual-state temperature control structure as described in any one of claims 1 to 9.

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