A preform heating device for a bottle blowing machine

Abstract

The utility model relates to bottle blowing machine technical field especially is concerned to a kind of bottle embryo heating device for bottle blowing machine, including rack and set on rack for heating the heating assembly to bottle embryo, heating assembly includes the mounting bracket fixedly connected on rack, set on mounting bracket for heating the heating lamp and heating rod to the inside and outside both sides of bottle embryo, heating lamp is slidably connected on the inner side wall of mounting bracket, and heating lamp is connected with first lifting drive component between mounting bracket;Heating rod is set to the intermediate position of mounting bracket, and the bottom end of heating rod is drivingly connected with second lifting drive mechanism for driving heating rod to extend into bottle embryo inside.The utility model is heated by heating lamp to bottle embryo outside radiation, and synchronously through heating rod to extend into bottle embryo inside, to make it can synchronously heat the inside and outside both sides of bottle embryo, to eliminate the temperature difference inside and outside caused by the thickness difference of bottle embryo, avoid appearing whitening phenomenon, to further improve bottle embryo transparency and finished product quality.

Description

Technical Field

[0001] This utility model relates to the field of blow molding machine technology, and in particular to a preform heating device for blow molding machines. Background Technology

[0002] Blow molding machines, as key equipment that uses blow molding technology to process plastic granules into hollow containers, are widely used in the packaging industry. Currently, most blow molding machines adopt a two-step blow molding process, which requires first making the plastic raw material into a preform, and then blowing the preform into shape. In the blow molding stage, the preform needs to be heated to a softened state, then placed in a split mold. After the mold is closed, compressed air is quickly introduced into the preform, causing the plastic preform to inflate and tightly adhere to the inner wall of the mold. After cooling and demolding, various hollow products are obtained. In this process, the heating effect of the preform has a significant impact on the quality of the final product.

[0003] In existing technologies, preforms are continuously moved to the heating station by a conveyor chain during the heating and softening process, and the outer periphery of the preform is heated using side-mounted heating tubes. However, due to significant differences in the thickness of preforms of different specifications and types, uneven heat distribution easily occurs during the heat conduction process from the outside to the inside. This results in the outer temperature of the preform being significantly higher than the inner wall temperature, causing uneven heating between the inside and outside of the preform. This uneven heating can lead to defects such as whitening and deformation in subsequent blow molding processes due to uneven internal stress, which in turn seriously affects the transparency of the preform, reduces the appearance quality of the product, and also adversely affects the physical properties and performance of hollow products. This restricts the improvement of production efficiency and product yield, and fails to meet the market demand for high-quality hollow containers. Utility Model Content

[0004] In order to address the technical deficiencies mentioned in the background art, the purpose of this utility model is to provide a preform heating device for blow molding machines, which effectively solves the problems of uneven heating, easy whitening, deformation, and limited applicability of existing heating devices.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A preform heating device for a blow molding machine includes a frame and a heating assembly mounted on the frame for heating the preform. The heating assembly includes a mounting bracket fixedly connected to the frame, a heating lamp and a heating rod mounted on the mounting bracket for heating the inner and outer sides of the preform. The heating lamp is slidably connected to the inner wall of the mounting bracket, and a first lifting drive mechanism is connected between the heating lamp and the mounting bracket. The heating rod is located in the middle of the mounting bracket, and a second lifting drive mechanism is driven to the bottom end of the heating rod for extending into the preform. The second lifting drive mechanism is connected to the bottom end of the frame and is synchronously driven with the first lifting drive mechanism. The heating lamp and the heating rod are connected by wiring to achieve synchronous heating of the inner and outer sides of the preform.

[0007] Preferably, the mounting bracket has a U-shaped structure and a hollow structure. A groove is provided on the side of the mounting bracket that is connected to the heating lamp, and the groove is connected to the inner cavity of the mounting bracket.

[0008] Preferably, the first lifting drive mechanism includes a nut seat, a transmission screw, and a drive motor. The nut seat is connected to the transmission screw, and a sliding plate is provided on one side of the nut seat. The transmission screw is axially disposed in the mounting bracket, and bearing fixing seats are provided at both ends of the transmission screw. The drive motor is fixed to one side of the mounting bracket, and the output end of the drive motor is connected to the transmission screw through a pulley assembly.

[0009] Preferably, the second lifting drive mechanism includes a cylinder mounting base, a lifting cylinder, and a telescopic rod. The cylinder mounting base is fixed to the bottom end of the frame by screws. The lifting cylinder is mounted on the cylinder mounting base, and the output end of the lifting cylinder passes through the frame and is connected to the telescopic rod for transmission. One end of the telescopic rod extends out to a mounting bracket and is connected to a heating rod.

[0010] Preferably, the heating lamp is detachably connected to the slide plate, and the heating lamp consists of a heating plate and multiple heating lamp beads connected in series on the heating plate.

[0011] Preferably, the heating rod is detachably connected to the telescopic rod, and the heating rod consists of a power connector and a heating coil disposed on the power connector.

[0012] Preferably, the heating assembly further includes a thermostat for detecting and controlling the heating temperature. The thermostat is located at the top of the mounting bracket and has a temperature sensor inside. The thermostat is connected to the heating lamp and the heating rod via the temperature sensor.

[0013] In summary, the beneficial effects of this utility model are as follows:

[0014] This invention uses a heating lamp to radiate heat to the outside of the preform, while simultaneously extending a heating rod into the preform to heat both the inside and outside of the preform at the same time. This eliminates the temperature difference between the inside and outside of the preform caused by thickness variations, preventing whitening and improving the transparency and quality of the preform. Furthermore, the first and second lifting drive mechanisms flexibly adjust the positions of the heating lamp and heating rod, allowing it to adapt to preforms of different specifications, broadening the applicability of the heating device and effectively improving the heating efficiency and quality of the preform. Attached Figure Description

[0015] Figure 1 This is a diagram showing the working state of the preform heating device for a blow molding machine according to this utility model;

[0016] Figure 2 This is a schematic diagram of the preform heating device for a blow molding machine according to this utility model;

[0017] Figure 3 This is a front view of the preform heating device for a blow molding machine according to this utility model;

[0018] Figure 4 This is a top view of the preform heating device for a blow molding machine according to this utility model;

[0019] Figure 5 yes Figure 4 A cross-sectional view of plane AA.

[0020] Explanation of the reference numerals in the figure:

[0021] 1. Frame; 2. Heating assembly; 21. Mounting bracket; 211. Slide rail; 22. Heating lamp; 23. Heating rod; 3. First lifting drive mechanism; 31. Nut seat; 311. Slide plate; 32. Transmission screw; 321. Bearing mounting seat; 33. Drive motor; 331. Pulley assembly; 4. Second lifting drive mechanism; 41. Cylinder mounting seat; 42. Lifting cylinder; 43. Telescopic rod; 5. Temperature controller; 6. Heating protective cover; 7. Circular conveyor line; 8. Clamping assembly; 9. Preform. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model are within the protection scope of the present utility model.

[0023] Those skilled in the art should understand that, in the disclosure of this utility model, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "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 utility model 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, the above terms should not be construed as limitations on this utility model.

[0024] In the description of this utility model, the use of terms such as "several" means one or more, with "multiple" meaning two or more. Terms like "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of terms like "first," "second," and "third" is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, the quantity of indicated technical features, or the sequential relationship between indicated technical features.

[0025] The following is in conjunction with the appendix Figure 1-5 The present invention provides a more detailed description of an embodiment of a preform heating device for a blow molding machine.

[0026] A preform heating device for a blow molding machine, such as Figure 1 , 2 As shown, the device includes a frame 1 and a heating assembly 2 mounted on the frame 1 for heating the preform 9. The heating assembly 2 includes a mounting bracket 21 fixedly connected to the frame 1, a heating lamp 22 and a heating rod 23 mounted on the mounting bracket 21 for heating the inner and outer sides of the preform 9. The heating lamp 22 is slidably connected to the inner wall of the mounting bracket 21, and a first lifting drive mechanism 3 is connected between the heating lamp 22 and the mounting bracket 21. The heating rod 23 is located in the middle of the mounting bracket 21, and a second lifting drive mechanism 4 is driven to the bottom of the heating rod 23 to extend into the preform 9. The second lifting drive mechanism 4 is connected to the bottom of the frame 1, and the second lifting drive mechanism 4 is synchronously driven with the first lifting drive mechanism 3. The heating lamp 22 and the heating rod 23 are connected by a circuit to achieve synchronous heating of the inner and outer sides of the preform 9.

[0027] Specifically, a circular conveyor line 7 is horizontally mounted on the top of the frame 1. This circular conveyor line 7 adopts a chain drive structure. During the continuous forward movement of the preform 9 driven by the circular conveyor line 7, clamping components 8 are evenly distributed on the surface of the circular conveyor line 7 to maintain the stability of the preform 9. The clamping components 8 are used to clamp and fix the preform 9 to be heated. When the circular conveyor line 7 moves the preform 9 to the heating station, the clamping components 8 clamp the tail portion of the preform 9, keeping the preform 9 vertical and its axis aligned with the central axis of the heating components. At this time, the circular conveyor line 7 briefly stops operating, providing a stable working position for the heating process.

[0028] The first lifting drive mechanism 3 and the second lifting drive mechanism 4 allow the positions of the heating lamp 22 and heating rod 23 to be flexibly adjusted according to the height, diameter, and other specifications of the preform 9. For different models of preform 9, no hardware components need to be replaced; simply inputting the corresponding parameters into the control system automatically adjusts the position of the heating components, enabling rapid model changeover production. This adaptive adjustment function significantly improves the equipment's versatility and reduces downtime caused by mold changes or equipment adjustments, making it particularly suitable for multi-variety, small-batch production scenarios.

[0029] Compared to traditional single-sided heating methods, where heat needs to be slowly conducted from the outside of the preform 9 to the inside, easily creating a large temperature difference between the inner and outer walls and leading to defects such as whitening and deformation during blow molding, this device uses simultaneous heating from both the heating lamp 22 and the heating rod 23. This allows both the inner and outer walls of the preform 9 to absorb heat simultaneously, shortening the heat conduction path and significantly reducing the temperature difference. The radiant heating of the heating lamp 22 and the internal heating of the heating rod 23 work together to form a bidirectional heat flow, ensuring that the plastic molecules soften uniformly during heating. This effectively eliminates internal stress caused by uneven temperature, improving the transparency of the preform 9 and the quality of the finished product. Furthermore, simultaneous heating reduces heat loss during conduction, resulting in lower energy consumption compared to traditional single-sided heating methods while achieving the same heating effect.

[0030] In this embodiment, the mounting bracket 21 has a U-shaped structure and is hollow. A groove 211 is provided on the side of the mounting bracket 21 that is connected to the heating lamp 22. The groove 211 is connected to the inner cavity of the mounting bracket 21.

[0031] Specifically, the mounting bracket 21, made of aluminum alloy, is bolted to the top of the frame 1, located directly above the circular conveyor line 7. The U-shaped opening of the mounting bracket faces the direction of the conveyor line's movement, facilitating the entry of the preform 9 into the heating zone along with the clamping assembly 8. When the mounting bracket 21 is connected to the frame 1, it is calibrated with a level to ensure that its inner wall is perpendicular to the conveying trajectory of the preform 9, providing a reference for the subsequent sliding adjustment of the heating lamp 22.

[0032] In this embodiment, the first lifting drive mechanism 3 includes a nut seat 31, a transmission screw 32, and a drive motor 33. The nut seat 31 is connected to the transmission screw 32, and a sliding plate 331 is provided on one side of the nut seat 31. The transmission screw 32 is axially disposed within the mounting bracket 21, and both ends of the transmission screw 32 are horizontally mounted in the inner cavity of the mounting bracket 21 via bearing fixing seats 321. The bearing fixing seats 321 are welded and fixed to the inner wall of the mounting bracket 21. The drive motor 33 is mounted on the outside of the mounting bracket 21 via a motor mount, and its output shaft is connected to one end of the transmission screw 32 via a pulley assembly 331. The nut seat 31 is fitted onto the transmission screw 32, and its inner side is bolted to the sliding plate 311, ensuring that when the drive motor 33 rotates, the nut seat 31 drives the sliding plate 311 to slide axially along the transmission screw 32.

[0033] Specifically, the first lifting drive mechanism 3 adopts the same structure as the screw drive method. The drive motor 33 serves as the power source, transmitting rotational motion to the transmission screw 32 via the pulley assembly 331. The transmission screw 32 and the nut seat 31 form a helical transmission pair, converting the rotational motion into linear motion of the nut seat 31. Since the sliding plate 311 is fixedly connected to the nut seat 31, the sliding plate 311 slides axially along the transmission screw 32 with the nut seat 31, driving the heating lamp 22 to move up and down. This screw drive method features high transmission accuracy and good stability, enabling precise control of the heating lamp 22's position to meet the heating requirements of preforms 9 of different specifications.

[0034] In this embodiment, the second lifting drive mechanism 4 includes a cylinder mounting base 41, a lifting cylinder 42, and a telescopic rod 43. The cylinder mounting base 41 is fixed to the bottom end of the frame 1 with screws. The lifting cylinder 42 is vertically mounted on the cylinder mounting base 41, and its output end extends upward through a pre-reserved through hole in the frame 1, and is connected to the lower end of the telescopic rod 43 via a coupling. A linear bearing is provided in the middle of the telescopic rod 43, which cooperates with the inner wall of the through hole in the frame 1 to ensure smooth lifting without shaking. After installation, by adjusting the position of the cylinder mounting base 41, it is ensured that when the heating rod 23 rises to the highest point, the heating coil is fully inserted into the preform 9, and when it descends to the lowest point, it is removed from below the preform 9.

[0035] Specifically, the lifting cylinder 42 of the second lifting drive mechanism 4 is a single-acting or double-acting cylinder, and the air pressure change in the cylinder is controlled by a solenoid valve. When the heating rod 23 needs to rise, the solenoid valve connects the air source, and compressed air enters the upper (or lower) chamber of the cylinder, pushing the piston rod to extend, which drives the heating rod 23 to move upward through the telescopic rod 43; when the heating rod 23 needs to descend, the solenoid valve switches to the exhaust state, and the piston rod retracts under the action of spring force or air pressure, causing the heating rod 23 to exit the preform 9. The cylinder drive has the advantages of fast response speed and stable thrust, which can realize the rapid positioning and reliable operation of the heating rod 23.

[0036] In this embodiment, the heating lamp 22 is detachably connected to the slide plate 211, and the heating lamp 22 is composed of a heating plate and a plurality of heating lamp beads connected in series on the heating plate.

[0037] Specifically, the heating lamp 22 uses quartz halogen bulbs. When powered on, the filament heats up to incandescence, emitting high-intensity infrared radiation. This infrared radiation penetrates the outer plastic layer of the preform 9, directly heating the internal molecular structure, increasing the kinetic energy of the plastic molecules and raising the temperature. The heating plate is made of aluminum alloy with good thermal conductivity, and multiple heating bulbs are evenly arranged and fixed to form a continuous heating area, ensuring uniform radiant heating of the outer side of the preform 9. Since the heating lamp 22 is slidably connected to the mounting bracket 21, its height can be adjusted to accommodate preforms 9 of different heights, ensuring that the radiant heating area always covers the main heating parts of the preform 9.

[0038] In this embodiment, as Figure 2 As shown, the heating rod 23 is detachably connected to the telescopic rod 43, and the heating rod 23 consists of a power connector and a heating coil disposed on the power connector.

[0039] Specifically, the heating coil of the heating rod 23 uses nickel-chromium alloy resistance wire wound on an insulating ceramic frame and wrapped with a high-temperature resistant metal sleeve. When current passes through the heating coil, the resistance wire generates Joule heat, which is conducted to the surrounding air through the metal sleeve, thereby heating the inner wall of the preform 9. The spiral structure design of the heating coil enables it to form a uniform thermal field inside the preform 9, avoiding localized overheating. The heating rod 23 is connected to the lifting cylinder 42 via a telescopic rod 43. The linear reciprocating motion of the cylinder allows the heating coil to extend and retract inside the preform 9, thereby adjusting the heating position according to the inner diameter of the preform 9 and ensuring that all parts of the inner wall are exposed to thermal radiation and conduction.

[0040] In this embodiment, as Figure 1 As shown, the heating assembly 2 also includes a thermostat 5 for detecting and controlling the heating temperature. The thermostat 5 is located at the top of the mounting bracket 21 and has a temperature sensor inside. The thermostat 5 is connected to the heating lamp 22 and the heating rod 23 via the temperature sensor.

[0041] Specifically, the temperature sensor built into the temperature controller 5 uses a thermocouple or resistance temperature detector (RTD) to quickly detect temperature changes in the heating lamp 22 and heating rod 23. The temperature signal is input to the control circuit board via an analog-to-digital converter (ADC) and compared with a preset temperature threshold. When the actual temperature is lower than the set value, the control circuit board outputs a signal to increase the input power of the heating element; when the actual temperature is higher than the set value, it decreases the input power or pauses heating. This closed-loop control method ensures temperature stability during heating and prevents uneven heating or overheating damage to the preform 9 due to excessive temperature fluctuations.

[0042] It is worth noting that, in order to further improve the heating effect on the preform, a heating protective cover 6 is installed on the outside of the circular conveyor belt 7. The heating protective cover 6 is made of high temperature resistant transparent material, which can not only observe the heating process, but also prevent operators from accidentally contacting high temperature parts, thus improving the safety of the equipment.

[0043] It is worth mentioning that this heating device is not only suitable for conventional cylindrical preforms, but also for irregularly shaped preforms (such as square and oval) and preforms made of different materials (such as PP and PC). Heating requirements can be met simply by adjusting the positions and heating power of the heating lamp 22 and heating rod 23 using the first lifting drive mechanism 3 and the second lifting drive mechanism 4, respectively. In the cosmetic packaging field, for small-diameter, high-height preforms 9, the heating rod 23 can penetrate deep into the preform 9 for precise heating, avoiding blow molding difficulties caused by insufficient internal heating. In the food packaging field, for thick-walled preforms 9, simultaneous internal and external heating ensures uniform softening, improving the physical and sealing properties of the product.

[0044] The working principle of this utility model:

[0045] First, the preform 9 is gripped and fed by the clamping assembly 8 and conveyed to the heating station of the heating device by the circular conveyor line 7. Then, the drive motor 33 starts, driving the transmission screw 32 to rotate via the pulley assembly 331. The nut seat 31 moves along the transmission screw 32 and, via the slide plate 311, lifts and lowers the heating lamp 22 along the slide groove 211 of the mounting bracket 21 to adjust it to a suitable height for the preform 9. At the same time, the lifting cylinder 42 is activated, and the telescopic rod 43 lifts the heating rod 23 to prepare to extend into the preform 9. The heating lamp 22 radiates heat to the outside of the preform 9, and the heating rod 23 extends into the preform 9, heating both inside and out simultaneously. The temperature controller 5 monitors and regulates the temperature in real time using a temperature sensor to ensure uniform heating. After heating reaches the target, the heating lamp 22 is lowered and reset by the first lifting drive mechanism 3, and the heating rod 23 is lowered and reset by the second lifting drive mechanism 4. The clamping assembly 8 then conveys the heated preform 9 to the next process, completing one heating cycle.

[0046] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A preform heating device for a blow molding machine, comprising a frame and a heating assembly disposed on the frame for heating the preform, characterized in that, The heating assembly includes a mounting bracket fixedly connected to the frame, a heating lamp and a heating rod mounted on the mounting bracket for heating the inner and outer sides of the preform. The heating lamp is slidably connected to the inner wall of the mounting bracket, and a first lifting drive mechanism is connected between the heating lamp and the mounting bracket. The heating rod is located in the middle of the mounting bracket, and a second lifting drive mechanism is driven to the bottom end of the heating rod for driving the heating rod to extend into the preform. The second lifting drive mechanism is connected to the bottom end of the frame, and the second lifting drive mechanism is synchronously driven with the first lifting drive mechanism. The heating lamp and the heating rod are connected by a circuit to achieve synchronous heating of the inner and outer sides of the preform.

2. The preform heating device for a blow molding machine according to claim 1, characterized in that, The mounting bracket has a U-shaped structure and is hollow. A sliding groove is provided on the side of the mounting bracket that is connected to the heating lamp, and the sliding groove is connected to the inner cavity of the mounting bracket.

3. The preform heating device for a blow molding machine according to claim 1, characterized in that, The first lifting drive mechanism includes a nut seat, a transmission screw, and a drive motor. The nut seat is connected to the transmission screw, and a sliding plate is provided on one side of the nut seat. The transmission screw is axially disposed in the mounting bracket, and bearing fixing seats are provided at both ends of the transmission screw. The drive motor is fixed to one side of the mounting bracket, and the output end of the drive motor is connected to the transmission screw through a pulley assembly.

4. The preform heating device for a blow molding machine according to claim 1, characterized in that, The second lifting drive mechanism includes a cylinder mounting base, a lifting cylinder, and a telescopic rod. The cylinder mounting base is fixed to the bottom of the frame with screws. The lifting cylinder is mounted on the cylinder mounting base, and the output end of the lifting cylinder passes through the frame and is connected to the telescopic rod for transmission. One end of the telescopic rod extends out to a mounting bracket and is connected to a heating rod.

5. The preform heating device for a blow molding machine according to claim 3, characterized in that, The heating lamp is detachably connected to the slide plate, and the heating lamp consists of a heating plate and multiple heating lamp beads connected in series on the heating plate.

6. The preform heating device for a blow molding machine according to claim 1, characterized in that, The heating rod is detachably connected to the telescopic rod, and the heating rod consists of a power connector and a heating coil disposed on the power connector.

7. The preform heating device for a blow molding machine according to claim 1, characterized in that, The heating assembly also includes a thermostat for detecting and controlling the heating temperature. The thermostat is located at the top of the mounting bracket and has a temperature sensor inside. The thermostat is connected to the heating lamp and the heating rod via the temperature sensor.

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