Blank preheating device for blow molding

Abstract

The utility model discloses a blank preheating device for blow molding, which belongs to the technical field of plastic bottle processing, and comprises a preheating box and a conveying guide rail for conveying bottle blanks, and further comprises a base, the bottle blanks are arranged on the base, and the conveying guide rail is used for conveying the base so as to enable the base to enter or exit from the preheating box; a heat-insulating cladding plate; and the control mechanism is used for controlling the heat insulation cladding plate to wrap the opening part of the bottle preform. The utility model solves the problem that the existing heating mode cannot prevent heat from diffusing to the mouth part of the bottle preform.

Description

Technical Field

[0001] This utility model relates to the field of plastic bottle processing technology, and in particular to a preheating device for blow molding preforms. Background Technology

[0002] In blow molding, uniform preheating of the preform is a crucial step in ensuring consistent bottle wall thickness and molding quality. Current technologies typically employ infrared radiation heating or hot air circulation to preheat the preform either as a whole or in sections. However, these traditional preheating devices have significant technical drawbacks: during the heating process, heat inevitably diffuses to the preform neck area (i.e., the threaded connection), causing the preform neck material to soften due to heat.

[0003] Because the preform mouth needs to maintain a precise geometric shape during subsequent blow molding processes to ensure a tight seal with the cap, premature heating of the preform mouth will cause two problems: First, the mouth mouth is prone to deformation under mechanical clamping or blow molding pressure after heating, leading to a decrease in the precision of the sealing surface; second, the mouth material may experience abnormal crystallinity due to secondary heating (such as temperature transfer from the blow molding mold), reducing creep resistance. While existing technologies attempt to alleviate this problem by shortening the heating time or lowering the heating temperature, this results in insufficient heating of the preform body, which in turn affects the material's ductility during the blow molding stage.

[0004] In view of this, the present invention provides a new solution to the above problems. Utility Model Content

[0005] The purpose of this invention is to provide a preheating device for blow molding preforms, which solves the problem that existing heating methods cannot prevent heat from diffusing to the preform opening.

[0006] The above-mentioned technical objective of this utility model is achieved through the following technical solution:

[0007] A preheating device for blow molding preforms includes a preheating chamber and a conveying guide for conveying preforms, and further includes:

[0008] A base on which the preform is placed, and a conveying guide rail for conveying the base so that the base enters or exits the preheating chamber;

[0009] Thermal insulation covering panel;

[0010] A control mechanism is provided for controlling the heat insulation covering plate to wrap around the mouth of the preform.

[0011] A further preferred embodiment is that: two heat-insulating covering plates are provided, and the two heat-insulating covering plates are respectively located on opposite sides of the preform opening. The control mechanism is used to drive the two heat-insulating covering plates to move closer or further apart from each other, so that the heat-insulating covering plates wrap around the preform opening.

[0012] A further preferred embodiment is that the control mechanism includes a protective box and a cylinder, the protective box being fixed on the base, and the cylinder being located inside the protective box.

[0013] A further preferred embodiment is that the outer surface of the protective box is provided with a heat insulation layer.

[0014] A further preferred embodiment is that there are two control mechanisms, which are located on opposite sides of the preform.

[0015] A further preferred embodiment is that the preform is inverted on the base, and the heat insulation covering plate is an arc-shaped plate that is adapted to the mouth of the preform.

[0016] A further preferred embodiment is that a heat-insulating sealing layer is fixed above the inner side of the heat-insulating covering plate, and the heat-insulating sealing layer is used to press against the heat-insulating covering plate and the bottle preform opening.

[0017] A further preferred embodiment is that a limiting part is fixed on the base, an insertion tube is provided on the limiting part, and the bottle preform mouth is inserted into the outer surface of the insertion tube and in contact with the limiting part.

[0018] A further preferred embodiment is that the preheating box is equipped with heating tubes and heat insulation baffles, with the heating tubes located on opposite sides of the preform conveying direction;

[0019] The heat insulation baffle is located below the heating tube and between the preform body and the preform opening, so that the control mechanism is located below the heat insulation baffle.

[0020] A further preferred embodiment is that the preheating box has a long, narrow channel shape and openings at both ends for the preform to enter and exit.

[0021] In summary, this utility model has the following beneficial effects:

[0022] The present invention relates to a preheating device for blow molding preforms, comprising a preheating chamber and a conveying guide rail for conveying preforms, as well as a base, a heat insulation covering plate and a control mechanism. The preforms are placed on the base, and the conveying guide rail is used to convey the base so that the base enters or exits the preheating chamber. The control mechanism is used to control the heat insulation covering plate to wrap around the mouth of the preforms.

[0023] During preheating, the preform is first placed on the base. Then, through a control mechanism, an insulating cover plate is placed over the outer surface of the preform opening. The base carrying the preform is then conveyed into the preheating chamber via a conveyor rail for drying. The process is simple and convenient. The insulating cover plate forming a physical barrier over the preform opening reduces heat transfer, solving the problem of heat diffusion to the preform opening that cannot be prevented in existing heating methods. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the embryo preheating device according to a preferred embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the internal structure of the preheating box according to a preferred embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the control mechanism, heat insulation covering plate, and base structure of a preferred embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram of the control mechanism, heat insulation covering plate, and base structure of a preferred embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of the base of a preferred embodiment of the present invention;

[0029] Figure 6 This is a schematic diagram of the structure of the heat insulation covering plate and the heat insulation sealing layer of a preferred embodiment of the present invention.

[0030] In the diagram, 1. Preheating box; 2. Conveying guide rail; 3. Opening; 4. Preform; 5. Base; 6. Heating tube; 7. Control mechanism; 71. Protective box; 72. Cylinder; 8. Insulation cover plate; 9. Limiting part; 10. Insertion tube; 11. Insulation sealing layer; 12. Insulation baffle. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Example: A preheating device for blow molding preforms, such as Figure 1-6 As shown, the system includes a preheating chamber 1, a conveyor rail 2, a base 5, a heat-insulating covering plate 8, and a control mechanism 7. The preheating chamber 1 has a long and narrow channel shape with openings 3 at both ends for the preforms 4 to enter and exit. The top of the preheating chamber 1 is arched upwards, resembling a tunnel. The long and narrow shape of the preheating chamber 1 is suitable for continuous production line layouts, reducing the equipment footprint, while ensuring that the preforms 4 are fully heated by extending the heating path. The arched structure reduces upward heat loss, forming an internal circulation of hot airflow and enhancing the temperature uniformity within the preheating chamber 1.

[0033] Preferably, the conveying guide rail 2 runs through the inside and outside of the preheating chamber 1 and is used to convey the base 5 that carries the preform 4. Specifically, the preform 4 is inverted on the base 5, and the conveying guide rail 2 is used to convey the preform 4 and the base 5 so that the preform 4 and the base 5 enter or exit the preheating chamber 1 along the length direction of the preheating chamber 1. During the conveying process, the preform 4 inverted on the base 5 keeps its opening 3 facing downward to prevent foreign objects from entering the interior of the preform 4, while facilitating the heating tube 6 to heat the outer wall of the preform 4.

[0034] Preferably, the conveyor rail 2 is a chain conveyor rail, a roller / belt composite rail, or other type, but most preferably a chain conveyor rail. The high load-bearing capacity of the chain structure is suitable for stable operation in high-temperature environments.

[0035] Preferably, the preheating chamber 1 is equipped with heating tubes 6, which are located on opposite sides of the preform 4 in the conveying direction. Optionally, the heating tubes 6 are electric heating tubes. The heating tubes 6 are distributed on both sides of the preform 4 in the conveying direction, which reduces the temperature gradient through symmetrical heat sources and prevents the preform 4 from being overheated or underheated locally.

[0036] Reference Figure 1-6 Two heat insulation covering plates 8 are provided, symmetrically arranged on opposite sides of the bottle preform 4 opening. The heat insulation covering plates 8 are arc-shaped and adapted to the opening of the bottle preform 4. Preferably, the heat insulation covering plates 8 are ceramic fiber boards or food-grade XPS extruded boards.

[0037] The control mechanism 7 is used to control the heat insulation coating plate 8 to wrap around the mouth of the preform 4. Specifically, the control mechanism 7 is used to move the two heat insulation coating plates 8 closer to each other or further apart so that the heat insulation coating plate 8 wraps around the mouth of the preform 4. The control mechanism 7 includes a protective box 71 and a cylinder 72. The protective box 71 is fixed on the base 5, and the cylinder 72 is installed inside the protective box 71.

[0038] In the above technical solution, two arc-shaped heat-insulating covering plates 8 are symmetrically arranged on both sides of the bottle preform 4 opening. They are driven by cylinder 72 to close synchronously, forming a ring-shaped wrapping structure that effectively covers the irregular surface of the bottle preform 4 opening and reduces heat loss through air gaps. The heat-insulating covering plates 8 are highly adapted to the shape of the bottle preform 4 opening, reducing the thermal resistance of the contact surface and preventing the bottle preform 4 opening from deforming due to heat.

[0039] Preferably, the outer surface of the protective box 71 is provided with a heat insulation layer, specifically, the heat insulation layer is formed after being coated with heat insulation paint.

[0040] In the above technical solution, the protective box 71 is mainly designed to insulate against heat and prevent the cylinder 72 from overheating, thus protecting the cylinder 72. Physical isolation reduces heat transfer to the cylinder 72, preventing the cylinder 72 from experiencing seal aging or hydraulic oil failure due to high temperatures.

[0041] It should be noted that a reflective aluminum foil layer can be added inside the protective box 71 to increase the radiant heat reflectivity to over 85%, further reducing heat accumulation.

[0042] Preferably, the heat insulation baffle 12 is located below the heating tube 6 and between the preform 4 body and the preform 4 opening, so that the protective box 71 is located below the heat insulation baffle 12. Specifically, the heat insulation baffle 12 is a ceramic fiber board or a food-grade XPS extruded board.

[0043] In the above technical solution, the baffle is located at the junction of the preform 4 body and the mouth, forming a "thermal isolation zone" to reduce heat diffusion to non-target areas (such as the mouth of the preform 4 and the protective box 71), ensuring uniform heating of the main body and improving molding accuracy. The protective box 71 is located below the heat insulation baffle 12, and the heat insulation layer of the protective box 71 further blocks the downward transfer of residual heat, ensuring that the working temperature of the bottom control mechanism 7 (such as the cylinder 72) is ≤60℃, preventing high temperature from causing aging of seals or failure of hydraulic oil.

[0044] Preferably, there are two control mechanisms 7, which are located on opposite sides of the preform 4, and each of the two control mechanisms 7 corresponds to one of the two heat insulation covering plates 8.

[0045] In the above technical solution, the dual control mechanism 7 independently drives the heat insulation covering plate 8, which can flexibly adjust the wrapping pressure to adapt to the processing requirements of different sized preforms 4 (such as thin-walled or thick-walled containers), and avoid damage to the preforms 4 due to excessive mechanical stress.

[0046] To improve the heat insulation effect, preferably, a heat insulation sealing layer 11 is fixed on the upper inner side of the heat insulation covering plate 8. The heat insulation sealing layer 11 is used to press against the heat insulation covering plate 8 and the mouth of the preform 4. The heat insulation sealing layer 11 is a soft material with a certain degree of elasticity.

[0047] In the above technical solution, the heat insulation sealing layer 11 fills the gap between the heat insulation covering plate 8 and the mouth of the preform 4, blocking the "thermal bridge" formed by direct contact between the two, thus making the heat transfer path longer. In addition, it can also form a physical barrier to reduce the transfer of heat from the preform 4 body to the mouth of the preform 4.

[0048] Preferably, a limiting part 9 is fixed on the base 5, and an insertion tube 10 is provided on the limiting part 9. The mouth of the preform 4 is inserted into the outer surface of the insertion tube 10 and in contact with the limiting part 9. A heat insulation pad (such as a mica sheet or XPS extruded board) can also be provided between the limiting part 9 and the base 5 to reduce heat transfer through the metal contact surface and lower the temperature of the base 5.

[0049] Usage and principle: During preheating, the preform 4 is first placed upside down on the insertion tube 10, and then the cylinder 72 is started so that the heat insulation covering plate 8 covers the outer surface of the mouth of the preform 4. Then, the base 5 carrying the preform 4 is sent into the preheating box 1 for drying through the conveying guide rail 2. It is simple and convenient to use.

[0050] This specific embodiment is merely an explanation of the present utility model and is not intended to limit the present utility model. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present utility model, they are protected by patent law.

Claims

1. A preheating device for blow molding preforms, comprising a preheating chamber (1) and a conveying guide rail (2) for conveying preforms (4), characterized in that: Also includes: The base (5) is on which the preform (4) is placed, and the conveying guide (2) is used to convey the base (5) so that the base (5) enters or exits the preheating box (1); Thermal insulation covering panel (8); Control mechanism (7) is used to control the heat insulation covering plate (8) to wrap around the mouth of the preform (4).

2. The preheating device for blow molding according to claim 1, characterized in that: Two heat insulation covering plates (8) are provided, and the two heat insulation covering plates (8) are respectively located on opposite sides of the mouth of the preform (4). The control mechanism (7) is used to drive the two heat insulation covering plates (8) to move closer or further away from each other so that the heat insulation covering plates (8) wrap around the mouth of the preform (4).

3. The preheating device for blow molding according to claim 1, characterized in that: The control mechanism (7) includes a protective box (71) and a cylinder (72). The protective box (71) is fixed on the base (5), and the cylinder (72) is located inside the protective box (71).

4. The preheating device for blow molding according to claim 3, characterized in that: The outer surface of the protective box (71) is provided with a heat insulation layer.

5. A preheating device for blow molding according to claim 3, characterized in that: There are two control mechanisms (7), which are located on opposite sides of the preform (4).

6. A preheating device for blow molding preforms according to claim 2, characterized in that: The preform (4) is inverted on the base (5), and the heat insulation covering plate (8) is an arc-shaped plate that is adapted to the mouth of the preform (4).

7. A preheating device for blow molding according to claim 6, characterized in that: A heat insulation sealing layer (11) is fixed on the upper inner side of the heat insulation covering plate (8), and the heat insulation sealing layer (11) is used to press against the heat insulation covering plate (8) and the mouth of the preform (4).

8. A preheating device for blow molding according to claim 6, characterized in that: A limiting part (9) is fixed on the base (5), and an insertion tube (10) is provided on the limiting part (9). The mouth of the preform (4) is inserted into the outer surface of the insertion tube (10) and contacts the limiting part (9).

9. A preheating device for blow molding preforms according to claim 1, characterized in that: The preheating box (1) is equipped with heating tubes (6) and heat insulation baffles (12), and the heating tubes (6) are located on opposite sides of the preform (4) in the conveying direction; The heat insulation baffle (12) is located below the heating tube (6) and between the body of the preform (4) and the mouth of the preform (4), so that the control mechanism (7) is located below the heat insulation baffle (12).

10. A preheating device for blow molding according to claim 1, characterized in that: The preheating box (1) is a long and narrow channel with openings (3) at both ends for the preform (4) to enter and exit.

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