Plastic bottle blank refinement post-treatment process based on multi-section temperature control

Abstract

The invention relates to the technical field of plastic bottle blank forming, in particular to a plastic bottle blank refining post-treatment process based on multi-section temperature control, which comprises the following steps that a feeding and discharging machine sequentially places plastic bottle blanks on a bottle blank fixing seat, and a conveying device conveys the bottle blank fixing seat carrying the plastic bottle blanks to move; the driving unit adjusts the height of each supporting track and sets the heating temperature of the main heating unit and each auxiliary heating unit, the bottom of the bottle blank fixing seat is attached to the supporting track to move, and the supporting track controls a plastic bottle blank to be located at the heating part in the main heating unit; according to the technical scheme, independent heating temperatures are set for different parts in the vertical direction of the bottle blanks through the main heating units and the auxiliary heating units, and the height positions of the bottle blanks in the heating process are accurately adjusted by changing the height of the supporting rail; the problem of uneven temperature distribution caused by a traditional single heating mode is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of plastic bottle preform molding, and in particular to a plastic bottle preform refined post-processing process based on multi-stage temperature control. Background Art

[0002] Plastic bottles play a crucial role in numerous sectors, particularly in the beverage and pharmaceutical industries. As a primary packaging format, they boast high production volumes and a wide range of applications. The plastic bottle manufacturing process typically involves heating the preform to a viscoplastic state before blow molding. The quality and speed of this heating step are key factors influencing the quality and yield of the finished bottle.

[0003] However, in industrial applications, to achieve higher quality preforms and further expand their application, it is necessary to control the temperature of the plastic preforms in different zones to achieve different temperature distributions along the vertical axis. Due to the poor thermal conductivity of plastic, it is difficult to ensure uniform temperature between the inner and outer walls during a short heating period. Furthermore, these varying temperatures can lead to cracking or partial whitening of the preforms during the subsequent blow molding process, making it difficult to meet the high-quality requirements for plastic bottles. Summary of the Invention

[0004] In view of the above-mentioned technical deficiencies, the purpose of the present invention is to provide a refined post-processing process for plastic bottle blanks based on multi-stage temperature control, comprising a conveying device, a loading and unloading machine, a plurality of bottle blank fixing seats, a main heating unit and a plurality of auxiliary heating units, a heat preservation unit is provided between adjacent main heating units and auxiliary heating units, a plurality of support rails located below the main heating units and auxiliary heating units, and a fixed rail located below the heat preservation unit are provided on one side of the conveying device, the support rails and the fixed rails are connected by a connecting rail, and the support rails are connected to a drive unit for driving the loading and unloading machine to rise and fall in the vertical direction; Step 1: The loading and unloading machines place the plastic preforms on the preform holders in sequence, and the conveying device transports the preform holders carrying the plastic preforms; Step 2: The staff adjusts the height of each support rail through the driving unit and sets the heating temperature of the main heating unit and each auxiliary heating unit; Step 3: The preform holder enters the main heating unit for heating. The bottom of the preform holder moves along the support rail, and the support rail controls the plastic preform to be located in the heating position in the main heating unit. Step 4: The plastic preform heated by the main heating unit moves to the insulation unit for a short transition, and then moves to the subsequent auxiliary heating unit following the preform holder. The preform holder moves along another support track so that the auxiliary heating unit can independently heat another part of the plastic preform. Step 5: After being processed by all the main heating units and auxiliary heating units, the plastic preforms are moved to the loading and unloading machine for unloading. The loading and unloading machine reloads the preform fixing seat, and steps 3 to 4 are repeated until all the plastic preforms are processed.

[0005] Preferably, the conveying device is fixedly mounted on the base, and at least two vertically extending guide rods are supported at the bottom of the support track. The guide rods are inserted into guide sleeves provided on the base, and a distance sensor for detecting the height of the support track is provided on the guide sleeve; the driving unit includes a rotary driver installed on the guide sleeve and located below the main heating unit, the distance sensor is connected to the rotary driver through a controller signal, a turntable is coaxially mounted on the working end of the rotary driver, the axis of the turntable is horizontally arranged perpendicular to the length direction of the support track, a connecting column is eccentrically arranged on the turntable, a connecting block is provided at the bottom of the support track, a waist-shaped groove extending along the length direction of the support track is provided on the connecting block, and the connecting column is slidably mounted in the waist-shaped groove.

[0006] The straight-line distance between the connecting column and the turntable axis is not less than the length of the plastic bottle blank installed on the bottle blank fixing seat; the width of the waist-shaped groove is the same as the diameter of the connecting column, and the length of the waist-shaped groove is not less than the straight-line distance between the connecting column and the turntable axis.

[0007] Preferably, sliding blocks are slidably installed at both ends of the fixed rail, and the sliding blocks move along the length direction of the fixed rail. The sliding blocks and the support rail are provided with hinged seats for rotationally connecting to the connecting rail at one end.

[0008] Preferably, the two ends of the connecting rail are set as round heads, and the axes of the round heads at both ends of the connecting rail are set horizontally perpendicular to the length direction of the supporting rail. The sliding block and the supporting rail are set with arc grooves matching the round heads at both ends of the connecting rail at one end facing the connecting rail.

[0009] Preferably, protruding limiting bumps are provided on both sides of the sliding block, and the limiting bumps are inserted into the insertion holes provided on the fixed rail. The limiting bumps and the insertion holes have the same width, and the limiting bumps and the insertion holes extend along the length direction of the fixed rail.

[0010] Preferably, the preform fixing seat includes a connecting seat for connecting to a conveying device, and a sleeve installed on the connecting seat, the axis of the sleeve is vertically arranged, a shaft column is coaxially installed in the sleeve, a mounting seat for placing the plastic bottle preform is coaxially installed on the top of the shaft column, and a ball is rotatably installed on the bottom of the shaft column, and the ball rotates in conjunction with the support rail and the fixed rail.

[0011] Preferably, a vertically extending spline groove is provided on the circumference of the shaft column, a spline sleeve is coaxially installed on the bottom of the sleeve, and the shaft column is spline-connected to the spline sleeve through the spline groove; a first bevel gear is coaxially installed on the outside of the spline sleeve, and the first bevel gear is meshed with a second bevel gear rotatably installed on the connecting seat, and the axis of the second bevel gear is horizontally arranged perpendicular to the length direction of the support track, and a synchronous gear is coaxially connected to the second bevel gear; a plurality of racks aligned with the main heating unit and the auxiliary heating unit are provided on the base, and the length of the racks is the same as the length of the main heating unit and the auxiliary heating unit. When the bottle blank fixing seat moves into the main heating unit and the auxiliary heating unit, the synchronous gear is meshed with the rack.

[0012] Preferably, the main heating unit, the auxiliary heating unit and the heat preservation unit are provided with an inner cavity which opens downward and extends along the moving path of the bottle blank holder, and the height of the inner cavity is not less than the height of the plastic bottle blank placed on the bottle blank holder.

[0013] Preferably, the main heating unit and the auxiliary heating unit are provided with a plurality of heaters extending horizontally along the length direction of the inner cavity on one side of the inner cavity, and the side wall of the inner cavity is provided with baffles located on the upper and lower sides of the heater.

[0014] Compared with the prior art, the present invention has the following beneficial effects: First, by arranging several primary and secondary heating units along the travel path of the preform holder, the present invention allows independent heating temperatures to be set for different vertical locations of the preform, such as the mouth, body, and bottom. A drive unit controls the height of the support rails against which the preform holder is attached, thereby precisely adjusting the preform's position within the primary and secondary heating units. This solves the problem of uneven temperature distribution caused by traditional single-heating methods.

[0015] Secondly, when the support rail is raised or lowered, the connecting rail rotates about the axis of the hinged base. The tension exerted by the supporting rail on the connecting rail causes the sliding block at its other end to slide on the fixed rail, adaptively compensating for positional differences caused by changes in the support rail's height. This maintains the connecting rail's connection with the fixed rail and the support rail, allowing the preform holder to slide smoothly from the support rail through the connecting rail to the fixed rail, preventing vibrations from the preform holder from affecting the heated preforms.

[0016] Third, the synchronous gear on the preform holder cooperates with the rack on the base, allowing the preform to rotate continuously as it passes through the primary and secondary heating units. This ensures uniform heating around the preform without the need for a motor, preventing localized overheating or insufficient heating. The rigid connection between the spline groove and the spline sleeve ensures slip-free rotation and allows the shaft to maintain rotation even after vertical movement to any height. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 It is a perspective view of the present invention.

[0019] Figure 2 It is the front view of the present invention.

[0020] Figure 3 for Figure 2 Cross-sectional view at AA.

[0021] Figure 4 for Figure 3 A partial enlarged view of point B.

[0022] Figure 5 for Figure 3 A partial enlarged view of point C.

[0023] Figure 6 A partial enlargement of the main view of the present invention Figure 1 .

[0024] Figure 7 A partial enlargement of the main view of the present invention Figure 2 .

[0025] Figure 8 It is a three-dimensional structural exploded diagram of the present invention;.

[0026] Figure 9 for Figure 8 A partial enlarged view of point D.

[0027] Figure 10 for Figure 8 A partial enlarged view of point E.

[0028] Figure 11 It is a three-dimensional view of the bottle blank fixing seat of the present invention.

[0029] Figure 12 This is a three-dimensional structural exploded view of the bottle blank fixing seat of the present invention.

[0030] Explanation of reference numerals: 1, conveying device; 1a, loading and unloading machine; 1b, supporting rail; 1b1, guide rod; 1b2, connecting block; 1b3, waist groove; 1b4, hinge seat; 1c, fixed rail; 1c1, sliding block; 1c2, limiting protrusion; 1c3, insertion hole; 1d, connecting rail; 1e, driving unit; 1e1, rotary drive; 1e2, turntable; 1e3, connecting column; 1f, base; 1f1, guide Sleeve; 1f2, distance sensor; 1f3, rack; 2, bottle blank fixing seat; 2a, connecting seat; 2a1, sleeve; 2a2, spline sleeve; 2b, shaft column; 2b1, mounting seat; 2b2, ball; 2b3, spline groove; 2c, first bevel gear; 2d, second bevel gear; 2d1, synchronous gear; 3, main heating unit; 3a, inner cavity; 3a1, baffle; 3b, heater; 4, auxiliary heating unit; 5, insulation unit. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] Reference Figures 1 to 12 : A multi-stage temperature-controlled refined post-processing process for plastic preforms includes a conveyor 1, a loading and unloading mechanism 1a, several preform holders 2, a primary heating unit 3, and several secondary heating units 4. A heat preservation unit 5 is disposed between adjacent primary and secondary heating units 3 and 4. One side of the conveyor 1 includes several support rails 1b positioned below the primary and secondary heating units 3 and 4, and a fixed rail 1c positioned below the heat preservation unit 5. The support rails 1b and the fixed rails 1c are connected by connecting rails 1d. The support rails 1b are connected to a drive unit 1e for vertically raising and lowering the loading and unloading mechanism 1a. The conveyor 1 in this application may be a conveyor belt. The conveyor 1 continuously transports the preform holders 2, and the loading and unloading mechanism 1a automatically completes loading and unloading, forming an assembly line operation. By arranging several primary heating units 3 and secondary heating units 4 along the travel path of the preform holders 2, this embodiment allows independent heating temperatures to be set for different vertical locations of the preform, such as the bottle mouth, bottle body, and bottle bottom, addressing the uneven temperature distribution problem caused by traditional single heating methods. The thicker bottom area of ​​the preform can be heated at a higher temperature using the main heating unit 3, while the thinner wall areas of the bottle body are heated at a lower temperature and more slowly using the secondary heating unit 4, thus avoiding localized overheating or underheating. The drive unit 1e controls the height of the support rail 1b against which the preform holder 2 is attached, thereby precisely adjusting the height of the preform within the main and secondary heating units 3 and 4. For example, raising the preform holder 2 so that the preform is positioned above the main heating unit 3 prioritizes heating the bottom of the preform, achieving "heating on demand." The insulation units 5 between adjacent heating units prevent heat diffusion, ensuring temperature independence in each heating zone and further enhancing the zoned temperature control effect.

[0033] Step 1: The loading and unloading machine 1a places the plastic preforms on the preform fixing seat 2 in sequence, and the conveying device 1 conveys the preform fixing seat 2 carrying the plastic preforms; Step 2: The staff adjusts the height of each support rail 1b through the driving unit 1e and sets the heating temperature of the main heating unit 3 and each auxiliary heating unit 4; Step 3: The preform holder 2 enters the main heating unit 3 for heating. The bottom of the preform holder 2 moves along the support rail 1b. The support rail 1b controls the location of the plastic preform in the main heating unit 3 for heating. Step 4: The plastic preform heated by the main heating unit 3 moves to the heat preservation unit 5 for a short transition, and then moves to the subsequent auxiliary heating unit 4 following the preform holder 2. The preform holder 2 moves along another support rail 1b so that the auxiliary heating unit 4 can independently heat another part of the plastic preform; Step 5: After being processed by all the main heating units 3 and the auxiliary heating units 4, the plastic preforms are moved to the loading and unloading machine 1a for unloading. The loading and unloading machine 1a reloads the preform fixing seat 2, and steps 3 to 4 are repeated until all the plastic preforms are processed.

[0034] In this embodiment, the plastic preform is initially heated by the main heating unit 3, then briefly transitions through the insulation unit 5 to allow the heat to slowly conduct into the interior of the preform. It then enters the auxiliary heating unit 4 to heat other parts. This step-by-step heating method can alleviate the problem of uneven temperature between the inner and outer walls caused by poor heat conduction, and avoid cracking or whitening caused by inconsistent stress between the inner and outer layers during blow molding. The number of main heating units 3, auxiliary heating units 4, and insulation units 5 can be increased or decreased, or their arrangement order adjusted according to production needs. The support track 1b is connected to the fixed track 1c via the connecting track 1d, ensuring a smooth transition when the preform holder 2 moves between different units, avoiding preform position shifts due to vibration that affect heating accuracy.

[0035] In order to achieve precise control of the height position of the support rail 1b, the following features are specifically set: The conveying device 1 is fixedly mounted on the base 1f, and at least two vertically extending guide rods 1b1 are supported at the bottom of the support rail 1b. The guide rods 1b1 are inserted into the guide sleeve 1f1 provided on the base 1f, and the guide sleeve 1f1 is provided with a distance sensor 1f2 for detecting the height of the support rail 1b; the driving unit 1e includes a rotary driver 1e1 installed on the guide sleeve 1f1 and located below the main heating unit 3, and the distance sensor 1f2 is connected to the rotary driver 1e1 through a controller signal, and a turntable 1e2 is coaxially mounted on the working end of the rotary driver 1e1, and the axis of the turntable 1e2 is horizontally arranged perpendicular to the length direction of the support rail 1b, and a connecting column 1e3 is eccentrically arranged on the turntable 1e2, and a connecting block 1b2 is provided at the bottom of the support rail 1b, and a waist-shaped groove 1b3 extending along the length direction of the support rail 1b is provided on the connecting block 1b2, and the connecting column 1e3 is slidably mounted in the waist-shaped groove 1b3.

[0036] In this embodiment, the support rail 1b is inserted into the guide sleeve 1f1 of the base 1f via a guide rod 1b1 at its bottom, ensuring stable vertical movement. A distance sensor 1f2 detects the current height of the support rail 1b in real time and transmits the data to a controller. When the bottom of the preform needs to be heated, the operator sets the target height of the support rail 1b through the controller. The distance sensor 1f2 converts the difference between the current and target heights into an electrical signal and feeds it back to the controller. Based on this signal difference, the controller activates the rotary actuator 1e1, which can be a servo motor. Due to the eccentric mounting of the connecting post 1e3, the rotation of the turntable 1e2 displaces the connecting post 1e3, which in turn propels the support rail 1b up and down along the guide rod 1b1 via the waist-shaped groove 1b3. As the support rail 1b moves, the distance sensor 1f2 continuously monitors its height until the target height is reached, at which point the controller stops the rotary actuator 1e1. This embodiment combines the real-time feedback of the distance sensor 1f2 with the precise transmission of the rotary driver 1e1 to precisely control the height of the support rail 1b, and can set the rotary driver 1e1 at the last auxiliary heating unit 4 to continuously drive the turntable 1e2 to rotate, thereby realizing the reciprocating movement of the support rail 1b in the vertical direction, thereby driving the bottle blank to be lifted and lowered reciprocally at the last auxiliary heating unit 4, comprehensively heating the bottle blank, and then directly carrying out blow molding.

[0037] In order to ensure that the height adjustment range of the drive unit 1e for the preform completely covers the length of the preform, the following features are specifically set: The straight-line distance between the connecting column 1e3 and the axis of the turntable 1e2 is not less than the length of the plastic bottle blank installed on the bottle blank fixing seat 2; the width of the waist-shaped groove 1b3 is the same as the diameter of the connecting column 1e3, and the length of the waist-shaped groove 1b3 is not less than the straight-line distance between the connecting column 1e3 and the axis of the turntable 1e2.

[0038] In this embodiment, the straight-line distance between the connecting column 1e3 and the axis of the turntable 1e2 is not less than the length of the bottle blank, ensuring that the lifting range of the support rail 1b can completely cover the length of the bottle blank, so that all parts of the bottle blank can be heated independently. The length of the waist-shaped groove 1b3 is not less than the straight-line distance between the connecting column 1e3 and the axis of the turntable 1e2, ensuring that when the turntable 1d2 rotates one circle, the connecting column 1e3 can move back and forth in the waist-shaped groove 1b3, ensuring that the drive unit 1e can fully cover the adjustment range.

[0039] In order to ensure that the connecting rail 1d always connects the fixed rail 1c and the supporting rail 1b and keeps the horizontal positions of the fixed rail 1c and the supporting rail 1b unchanged during the lifting and lowering adjustment of the supporting rail 1b, the following features are specifically set: Sliding blocks 1c1 are slidably installed at both ends of the fixed track 1c, and the sliding blocks 1c1 move along the length direction of the fixed track 1c. The sliding blocks 1c1 and the support track 1b are provided with a hinge seat 1b4 for rotating and connecting the connecting track 1d at one end thereof.

[0040] In this embodiment, when the drive unit 1e controls the support rail 1b to rise and fall, the connecting rail 1d rotates about the axis of the hinged seat 1b4. The tension exerted by the support rail 1b causes the connecting rail 1d to pull the sliding block 1c1 at its other end to slide on the fixed rail 1c, thereby adaptively compensating for positional differences caused by changes in the height of the support rail 1b. This maintains the connection between the connecting rail 1d, the fixed rail 1c, and the support rail 1b, while also ensuring that the fixed rail 1c and support rail 1b do not shift horizontally, thus ensuring that the preform holder 2 can smoothly transition between the rails.

[0041] In order to ensure smooth movement of the preform holder 2 between the support track 1b, the connecting track 1d and the fixed track 1c, the following features are specifically provided: The two ends of the connecting rail 1d are set as round heads, and the axes of the round heads at both ends of the connecting rail 1d are set horizontally perpendicular to the length direction of the supporting rail 1b. The sliding block 1c1 and the support rail 1b are set at one end facing the connecting rail 1d with arc grooves matching the round heads at both ends of the connecting rail 1d.

[0042] In this embodiment, the rounded ends of the connecting rail 1d tightly mate with the curved grooves of the sliding block 1c1 and support rail 1b. During the raising and lowering of the support rail 1b, the connecting rail 1d flexibly rotates within the curved grooves around the axis of the rounded ends, while the sliding block 1c1 simultaneously slides along the fixed rail 1c, adaptively adjusting the position and angle of the connecting rail 1d. When the preform holder 2 moves to the rail junction, the smooth transition between the rounded ends and the curved grooves of the connecting rail 1d allows it to slide smoothly from the support rail 1b through the connecting rail 1d to the fixed rail 1c, preventing vibrations from the preform holder 2 from affecting the heated preforms.

[0043] In order to ensure that the sliding block 1c1 can only move in the horizontal direction, the following features are specifically set: The sliding block 1c1 is provided with protruding limiting bumps 1c2 on both sides. The limiting bumps 1c2 are inserted into the insertion holes 1c3 provided on the fixed rail 1c. The limiting bumps 1c2 and the insertion holes 1c3 have the same width and extend along the length direction of the fixed rail 1c.

[0044] In this embodiment, the sliding block 1c1 limits the moving direction of the sliding block 1c1 through the cooperation between the limiting protrusion 1c2 and the insertion hole 1c3 on the fixed rail 1c, and also prevents the sliding block 1c1 from being separated from the fixed rail 1c.

[0045] In order to solve the problem of how the preform holder 2 can move horizontally with the working surface of the conveyor 1 while cooperating with the support rail 1b to change the height of the plastic preform, the following features are specifically set: The bottle blank fixing seat 2 includes a connecting seat 2a for connecting to the conveying device 1, and a sleeve 2a1 installed on the connecting seat 2a. The axis of the sleeve 2a1 is set vertically, and a shaft column 2b is coaxially installed in the sleeve 2a1. A mounting seat 2b1 for placing plastic bottle blanks is coaxially installed on the top of the shaft column 2b. A ball 2b2 is rotatably installed on the bottom of the shaft column 2b, and the ball 2b2 rotates in contact with the support rail 1b and the fixed rail 1c.

[0046] In this embodiment, the connecting base 2a of the preform holder 2 is connected to the conveyor 1. Driven by the conveyor 1, the preform holder 2 moves horizontally. A shaft 2b is inserted into a sleeve 2a1. The mounting base 2b1 at its top is used to hold the plastic preform. The ball bearings 2b2 at its bottom rotate against the surface of the support rail 1b. Since the shaft 2b can move axially within the sleeve 2a1, as the height of the support rail 1b changes, the shaft 2b drives the mounting base 2b1 and the plastic preforms to rise and fall synchronously. The ball bearings 2b2 at the bottom of the shaft 2b roll in contact with the support rail 1b and the fixed rail 1c, significantly reducing frictional resistance during the movement of the preform holder 2 compared to sliding friction.

[0047] In order to ensure uniformity around the preform during heating, the following features are specifically set: A vertically extending spline groove 2b3 is provided on the circumference of the shaft column 2b, and a spline sleeve 2a2 is coaxially installed on the bottom of the sleeve 2a1. The shaft column 2b is spline-connected to the spline sleeve 2a2 through the spline groove 2b3; a first bevel gear 2c is coaxially installed on the outside of the spline sleeve 2a2, and the first bevel gear 2c is meshed with the second bevel gear 2d rotatably installed on the connecting seat 2a. The axis of the second bevel gear 2d is horizontally arranged perpendicular to the length direction of the support track 1b, and the second bevel gear 2d is coaxially connected with a synchronous gear 2d1; a plurality of racks 1f3 aligned with the main heating unit 3 and the auxiliary heating unit 4 are provided on the base 1f, and the length of the rack 1f3 is the same as that of the main heating unit 3 and the auxiliary heating unit 4. When the bottle blank fixing seat 2 moves into the main heating unit 3 and the auxiliary heating unit 4, the synchronous gear 2d1 is meshed with the rack 1f3.

[0048] In this embodiment, the preform holder 2 moves horizontally with the conveyor 1. When the preform holder 2 enters the primary heating unit 3 or the secondary heating unit 4, the synchronous gear 2d1 engages with the rack 1f3 on the base 1f. Since the rack 1f3 is fixed, the synchronous gear 2d1 is driven to rotate by the rack 1f3 during horizontal movement, driving the second bevel gear 2d in turn. The second bevel gear 2d engages with the first bevel gear 2c, converting the horizontal rotational motion into vertical rotation. The splined sleeve 2a2, via the spline groove 2b3, drives the shaft 2b and the preform on the mounting base 2b1 in synchronous rotation. The preform rotates continuously during heating, ensuring uniform heat distribution around the circumference without the need for a motor, thus preventing local overheating or underheating. The rigid connection between the spline groove 2b3 and the splined sleeve 2a2 ensures slip-free rotation and allows the shaft 2b to maintain rotation even after vertical movement to any height.

[0049] In order to ensure that the main heating unit 3, the auxiliary heating unit 4 and the heat preservation unit 5 can allow the preforms at any height to pass through and maintain the function of heating the preforms in sections, the following features are specifically set: The main heating unit 3, the auxiliary heating unit 4 and the heat preservation unit 5 are provided with an inner cavity 3a which opens downward and extends along the moving path of the bottle blank fixing seat 2. The height of the inner cavity 3a is not less than the height of the plastic bottle blank placed on the bottle blank fixing seat 2.

[0050] The main heating unit 3 and the auxiliary heating unit 4 are located on one side of the inner cavity 3a and are provided with a plurality of heaters 3b extending horizontally along the length direction of the inner cavity 3a. The side wall of the inner cavity 3a is provided with baffles 3a1 located on the upper and lower sides of the heaters 3b.

[0051] In this embodiment, when the preform holder 2 carries the plastic preform through the primary heating unit 3, secondary heating unit 4, and insulation unit 5, heaters 3b extending horizontally along the length of the inner cavity 3a begin operating to heat the preform. Simultaneously, baffles 3a1 located above and below heaters 3b on the sidewalls of the inner cavity 3a prevent heat from dissipating upward or downward, concentrating the heat on the preform surface. Because the height of the inner cavity 3a is not less than the height of the preform, the preform can enter smoothly regardless of how high the support rail 1b raises the preform, ensuring segmented heating of different preform areas.

[0052] Working principle: the loading and unloading machine 1a places the plastic bottle blanks on the bottle blank holder 2 in sequence, and the conveying device 1 transports the bottle blank holder 2 carrying the plastic bottle blanks; the staff adjusts the height of each support rail 1b through the driving unit 1e and sets the heating temperature of the main heating unit 3 and each auxiliary heating unit 4; the bottle blank holder 2 enters the main heating unit 3 for heating, and the bottom of the bottle blank holder 2 moves in contact with the support rail 1b, and the support rail 1b controls the part of the plastic bottle blank that is heated in the main heating unit 3; the plastic bottle blank heated by the main heating unit 3 moves to the insulation unit 5 for a short transition, and then follows the bottle blank holder 2 to move to the subsequent auxiliary heating unit 4, and the bottle blank holder 2 moves in contact with another support rail 1b so that the auxiliary heating unit 4 independently heats another part of the plastic bottle blank.

[0053] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A plastic bottle preform refinement post-processing process based on multi-stage temperature control, characterized in that: The invention comprises a conveying device (1), a loading and unloading machine (1a), a plurality of preform fixing seats (2), a main heating unit (3) and a plurality of auxiliary heating units (4); a heat preservation unit (5) is provided between adjacent main heating units (3) and auxiliary heating units (4); a plurality of support rails (1b) located below the main heating units (3) and auxiliary heating units (4) and a fixed rail (1c) located below the heat preservation unit (5) are provided on one side of the conveying device (1); the support rails (1b) and the fixed rails (1c) are connected by a connecting rail (1d); the support rails (1b) are connected to a driving unit (1e) for driving the loading and unloading machine (1a) to rise and fall in a vertical direction; Step 1: The loading and unloading machine (1a) places the plastic bottle blanks on the bottle blank fixing seat (2) in sequence, and the conveying device (1) conveys the bottle blank fixing seat (2) carrying the plastic bottle blanks; Step 2: The staff adjusts the height of each support rail (1b) through the driving unit (1e) and sets the heating temperature of the main heating unit (3) and each auxiliary heating unit (4); Step 3: The preform holder (2) enters the main heating unit (3) for heating, and the bottom of the preform holder (2) moves in contact with the support rail (1b), and the support rail (1b) controls the location of the plastic preform in the main heating unit (3) for heating; Step 4: The plastic preform heated by the main heating unit (3) moves to the heat preservation unit (5) for a short transition, and then moves to the subsequent auxiliary heating unit (4) following the preform fixing seat (2). The preform fixing seat (2) moves in contact with another support rail (1b) so that the auxiliary heating unit (4) independently heats another part of the plastic preform. Step 5: After being processed by all the main heating units (3) and the auxiliary heating units (4), the plastic bottle blanks are moved to the loading and unloading machine (1a) for unloading. The loading and unloading machine (1a) reloads the bottle blank fixing seat (2). Steps 3 to 4 are repeated until all the plastic bottle blanks are processed.

2. The plastic bottle preform refinement post-processing process based on multi-stage temperature control according to claim 1, characterized in that: The conveying device (1) is fixedly mounted on a base (1f), and at least two vertically extending guide rods (1b1) are provided at the bottom of the support track (1b). The guide rods (1b1) are inserted into guide sleeves (1f1) provided on the base (1f), and a distance sensor (1f2) for detecting the height of the support track (1b) is provided on the guide sleeve (1f1); The driving unit (1e) comprises a rotary driver (1e1) mounted on a guide sleeve (1f1) and located below the main heating unit (3); a distance sensor (1f2) is connected to the rotary driver (1e1) via a controller signal; a turntable (1e2) is coaxially mounted on the working end of the rotary driver (1e1); the axis of the turntable (1e2) is arranged horizontally and perpendicular to the length direction of the support track (1b); a connecting column (1e3) is eccentrically arranged on the turntable (1e2); a connecting block (1b2) is provided at the bottom of the support track (1b); a waist-shaped groove (1b3) extending along the length direction of the support track (1b) is provided on the connecting block (1b2); and the connecting column (1e3) is slidably mounted in the waist-shaped groove (1b3).

3. The plastic bottle preform refinement post-processing process based on multi-stage temperature control according to claim 2, characterized in that: The straight-line distance between the connecting column (1e3) and the axis of the turntable (1e2) is not less than the length of the plastic preform mounted on the preform fixing seat (2); The width of the waist-shaped groove (1b3) is the same as the diameter of the connecting column (1e3), and the length of the waist-shaped groove (1b3) is not less than the straight-line distance between the connecting column (1e3) and the axis of the turntable (1e2).

4. The plastic bottle preform refinement post-processing process based on multi-stage temperature control according to claim 2, characterized in that: Sliding blocks (1c1) are slidably mounted on both ends of the fixed track (1c), and the sliding blocks (1c1) move along the length direction of the fixed track (1c). The sliding blocks (1c1) and the supporting track (1b) are provided with hinged seats (1b4) for rotatably connecting to the connecting track (1d) at one end thereof.

5. The plastic bottle preform refinement post-processing process based on multi-stage temperature control according to claim 4, characterized in that: Both ends of the connecting track (1d) are provided with round heads, and the axes of the round heads at both ends of the connecting track (1d) are arranged horizontally and perpendicular to the length direction of the supporting track (1b). The sliding block (1c1) and the supporting track (1b) are provided with arc grooves matching the round heads at both ends of the connecting track (1d) at one end facing the connecting track (1d).

6. The process for fine post-processing of plastic preforms based on multi-stage temperature control according to claim 4, characterized in that: Protruding limiting protrusions (1c2) are provided on both sides of the sliding block (1c1); the limiting protrusions (1c2) are inserted into insertion holes (1c3) provided on the fixed track (1c); the limiting protrusions (1c2) and the insertion holes (1c3) have the same width; the limiting protrusions (1c2) and the insertion holes (1c3) extend along the length direction of the fixed track (1c).

7. The plastic bottle preform refinement post-processing process based on multi-stage temperature control according to claim 2, characterized in that: The preform fixing seat (2) comprises a connecting seat (2a) for connecting to a conveying device (1), and a sleeve (2a1) mounted on the connecting seat (2a), wherein the axis of the sleeve (2a1) is arranged vertically, a shaft column (2b) is coaxially mounted in the sleeve (2a1), a mounting seat (2b1) for placing the plastic preform is coaxially mounted on the top of the shaft column (2b), and a ball (2b2) ​​is rotatably mounted on the bottom of the shaft column (2b), and the ball (2b2) ​​rotates in contact with the support track (1b) and the fixed track (1c).

8. The plastic bottle preform refinement post-processing process based on multi-stage temperature control according to claim 7, characterized in that: A vertically extending spline groove (2b3) is provided on the circumference of the shaft column (2b), a spline sleeve (2a2) is coaxially mounted on the bottom of the sleeve (2a1), and the shaft column (2b) is spline-connected to the spline sleeve (2a2) via the spline groove (2b3); A first bevel gear (2c) is coaxially mounted on the outside of the spline sleeve (2a2), the first bevel gear (2c) is meshedly connected with a second bevel gear (2d) rotatably mounted on the connecting seat (2a), the axis of the second bevel gear (2d) being arranged horizontally perpendicular to the length direction of the support track (1b), and the second bevel gear (2d) is coaxially connected to a synchronous gear (2d1); A plurality of racks (1f3) aligned with the main heating unit (3) and the auxiliary heating unit (4) are provided on the base (1f). The length of the racks (1f3) is the same as that of the main heating unit (3) and the auxiliary heating unit (4). When the preform fixing seat (2) moves into the main heating unit (3) and the auxiliary heating unit (4), the synchronous gear (2d1) is meshed and connected with the racks (1f3).

9. The plastic bottle preform refinement post-processing process based on multi-stage temperature control according to claim 2, characterized in that: The main heating unit (3), the auxiliary heating unit (4) and the heat-insulating unit (5) are provided with an inner cavity (3a) opening downward and extending along the moving path of the bottle blank fixing seat (2); the height of the inner cavity (3a) is not less than the height of the plastic bottle blank placed on the bottle blank fixing seat (2).

10. The plastic bottle preform refinement post-processing process based on multi-stage temperature control according to claim 9, characterized in that: The main heating unit (3) and the auxiliary heating unit (4) are provided on one side of the inner cavity (3a) with a plurality of heaters (3b) extending horizontally along the length direction of the inner cavity (3a), and the side wall of the inner cavity (3a) is provided with baffles (3a1) located on the upper and lower sides of the heaters (3b).

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