High-temperature sterilization process and high-temperature sterilization system for plastic bottles

Abstract

The application provides a high-temperature sterilization process and a high-temperature sterilization system for plastic bottles to solve the problem that plastic bottles cannot directly enter the next process after high-temperature steam sterilization and affect the appearance and use of the plastic bottles. The high-temperature sterilization process comprises the following steps: sealing detection of the plastic bottles; the plastic bottles are loaded into a sterilization metal mold, and the plastic bottles are completely wrapped and sealed by a sterilization cavity of the sterilization metal mold, the shape of the sterilization cavity is matched with the overall outer contour of the plastic bottles to be treated, and the inner wall of the sterilization cavity is in contact with the outer wall of the plastic bottles; high-temperature sterilization; cooling, taking out the plastic bottles, and completing the sterilization. The high-temperature sterilization system comprises a sterilization metal mold, a heating assembly, a cooling assembly and the like. The high-temperature sterilization process and the high-temperature sterilization system can be operated at normal pressure, the appearance and use of the plastic bottles are not affected, and the plastic bottles can directly enter the next process after high-temperature sterilization without drying.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sterilization, in particular to a high-temperature sterilization process and system for plastic bottles. BACKGROUND

[0002] At present, in order to completely solve the problem of difficult sterilization of bacteria spores and the like, the plastic bottles sealed after filling are generally treated by high-pressure steam sterilization in the wet heat sterilization process, that is, the plastic bottles are heated to 121 DEG C in a closed pressure container by steam or water, and after a certain period of heat preservation, forced cooling is started, and gas is injected for pressure balance during cooling, and gradually slowly cooled to normal pressure.

[0003] However, on the one hand, the plastic bottles cannot directly enter the next process such as labeling and coding after high-temperature steam sterilization. On the other hand, the plastic bottles will deform (such as flat convex, bottom convex, etc.) after high-temperature steam sterilization, which affects the appearance and use function of the plastic bottles. SUMMARY

[0004] The present application provides a high-temperature sterilization process and system for plastic bottles, which can be operated at normal pressure, and the appearance and use function of the plastic bottles are not affected. The plastic bottles can directly enter the next process after high-temperature sterilization without drying.

[0005] The technical solution adopted by the present application is as follows:

[0006] A high-temperature sterilization process for plastic bottles, the high-temperature sterilization process comprising the following steps:

[0007] Step S1, sealing detection is performed on the plastic bottles after filling, and the plastic bottles with leakage are removed; Step S2, the plastic bottles are loaded into a sterilization metal mold, and the plastic bottles are completely wrapped and sealed by a sterilization cavity in the sterilization metal mold; wherein the shape of the sterilization cavity is adapted to the overall outer contour of the plastic bottles to be treated, and the inner wall of the sterilization cavity is in contact with the outer wall of the plastic bottles;

[0008] Step S3, the sterilization metal mold is heated, and after the temperature of the sterilization metal mold is raised to a first preset temperature, the temperature is maintained for a preset period of time;

[0009] Step S4, the sterilization metal mold is cooled, and the plastic bottles are taken out after the temperature of the sterilization metal mold is reduced to a second preset temperature, and the sterilization is completed.

[0010] Further, the sealing detection method of the plastic bottle in step S1 is a squeezing leak detection method.

[0011] A high-temperature sterilization system for plastic bottles for implementing the aforementioned high-temperature sterilization process for plastic bottles, characterized in that the high-temperature sterilization system comprises:

[0012] A sterilization metal mold, wherein a sterilization cavity is arranged in the sterilization metal mold; the shape of the sterilization cavity is adapted to the overall outer contour of the plastic bottle to be processed;

[0013] A heating assembly arranged on the sterilization metal mold, which is heated by an electric heating method or a heat conduction medium heat transfer method to raise the temperature of the sterilization metal mold to a first preset temperature;

[0014] A cooling assembly arranged on the sterilization metal mold, which is cooled by an air cooling method or a cooling medium heat absorption method to lower the temperature of the sterilization metal mold to a second preset temperature;

[0015] A temperature sensor, which is dispersedly arranged on the sterilization metal mold, and the probe part thereof is adjacent to the sterilization cavity;

[0016] A driving mechanism connected with the sterilization metal mold, which cooperates to realize mold opening or mold closing of the sterilization metal mold;

[0017] A controller connected with the heating assembly, the cooling assembly, the temperature sensor, and the driving mechanism, respectively.

[0018] Further, a heat insulation layer is arranged on the outer wall of the sterilization metal mold.

[0019] Further, the sterilization metal mold comprises:

[0020] A first mold, wherein one or more first cavities are arranged on the first mold from the parting surface; the shape of the first cavity is consistent with the outer contour of the part of the plastic bottle except the bottle bottom area, and the bottom of the first cavity is open;

[0021] A second mold, wherein one or more second cavities are arranged on the second mold from the parting surface; the number of the second cavities is consistent with the number of the first cavities, and the shape of the second cavity is consistent with the outer contour of the remaining part of the plastic bottle except the bottle bottom area, and the bottom of the second cavity is open;

[0022] A bottom mold, wherein the number of the bottom mold is consistent with the number of the second cavities, and the shape of the upper surface of the bottom mold is consistent with the outer contour of the bottom area of the plastic bottle;

[0023] Wherein, the parting surface of the first mold and the parting surface of the second mold are in contact when the sterilization metal mold is closed; each first cavity corresponds to a second cavity, and the bottom mold is located at the open area of the combined structure of the first cavity and the second cavity and blocks the open lower end of the first cavity and the second cavity; the enclosed area of the inner wall of the first cavity, the inner wall of the second cavity and the upper surface of the bottom mold constitutes the closed sterilization cavity.

[0024] Further, when the heating assembly adopts an electric heating mode, it includes a tubular or rod-shaped electric heating element; the first mold is provided with a plurality of first mounting holes, and the second mold is provided with a plurality of second mounting holes; the electric heating element is arranged in the first mounting hole and the second mounting hole, respectively;

[0025] Alternatively, when the heating assembly adopts a heat conduction medium heat transfer mode, it includes a storage tank and a delivery pump; the storage tank contains a heat conduction medium and is provided with an electric heater or a heating jacket layer; the first mold is provided with a first hot runner, and the second mold is provided with a second hot runner; the first hot runner and the second hot runner are connected with the storage tank and the delivery pump.

[0026] Further, when the cooling assembly adopts an air cooling mode, it includes a fan; the fan is arranged on the surface of the sterilization metal mold;

[0027] Alternatively, when the cooling assembly adopts a cooling medium heat absorption mode, it includes a water tank and a water pump; the water tank contains a cooling medium; a first cold runner is provided on the first mold, and a second cold runner is provided on the second mold; the first cold runner and the second cold runner are connected with the water tank and the water pump.

[0028] Further, the first mounting hole is arranged along the length direction or the height direction of the first mold; the second mounting hole is arranged along the length direction or the height direction of the second mold; the first hot runner and the second hot runner are a plurality of parallel straight hot runners or an S-shaped hot runner; the first cold runner and the second cold runner are a plurality of parallel straight hot runners or an S-shaped hot runner;

[0029] And / or, the first mounting hole, the second mounting hole, the first hot runner, the second hot runner, the first cold runner and the second cold runner are arranged adjacent to the sterilization cavity;

[0030] And / or, when the first installation hole and the second installation hole are arranged in the length direction of the first mold and the second mold respectively, the axial center of each first installation hole in the first mold height direction is substantially equal to the distance between the point on the first cavity inner wall and the horizontal direction, and the axial center of each second installation hole in the second mold height direction is substantially equal to the distance between the point on the second cavity inner wall and the horizontal direction.

[0031] Further, the first cold runner and the first installation hole are alternately arranged, and the second cold runner and the second installation hole are alternately arranged.

[0032] Further, the bottom mold is provided with a bottom mold installation hole or a bottom mold hot runner, and is matched with the heating assembly; the bottom mold is also provided with a bottom mold cold runner, and is matched with the cooling assembly.

[0033] The beneficial effects of the present application are:

[0034] 1. Compared with the prior art, the high-temperature sterilization process for plastic bottles in the present application adopts a matched high-temperature sterilization system composed of sterilization metal molds and the like, the equipment composition is relatively simple, and the high-temperature sterilization can be carried out under normal pressure, replacing the sealed pressure container, without using compressed air for pressure preservation, and the safety factor is higher.

[0035] 2. The plastic bottle is completely wrapped and sealed by the sterilization cavity in the sterilization metal mold, and the inner wall of the sterilization cavity contacts the outer wall of the plastic bottle, so that the expansion of the plastic bottle and the liquid filled in the plastic bottle under the heated state is constrained by the sterilization cavity, thereby effectively ensuring the appearance form and use function of the plastic bottle.

[0036] 3. For non-circular cross-section special-shaped plastic bottles, the weight of the plastic bottle can be appropriately reduced under the condition of ensuring the appearance form and use function of the non-circular cross-section special-shaped plastic bottle, thereby reducing the production cost.

[0037] 4. The plastic bottle is not directly contacted with water vapor and the like, and the surface of the plastic bottle after high-temperature sterilization treatment is basically dry, so the next step such as label sticking and code printing can be directly carried out.

[0038] 5. The high-temperature sterilization treatment is suitable for plastic bottles with circular or square cross-sections, and is also suitable for high-temperature sterilization treatment of non-circular cross-section special-shaped plastic bottles, and has a wide range of applications. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced. Obviously, the accompanying drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0040] Figure 1 A flowchart of the high-temperature sterilization process for the plastic bottle in Embodiment 1.

[0041] Figure 2 A structure diagram of the metal mold in Embodiment 2 when the mold is closed.

[0042] Figure 3 A structure diagram of the metal mold in Embodiment 2 when the mold is closed.

[0043] Figure 4 A structure diagram of the metal mold in Embodiment 2 when the mold is opened. DETAILED DESCRIPTION

[0044] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0045] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of a specific example are described in the following. Of course, they are only examples, and the purpose is not to limit the present application.

[0046] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0047] Embodiment 1

[0048] In this embodiment, a high-temperature sterilization process for a plastic bottle is provided, and a flowchart thereof is shown in FIG. 1. Figure 1 The high-temperature sterilization process includes the following steps:

[0049] Step S1, sealing detection is performed on the plastic bottle after filling, and the plastic bottle with leakage is removed;

[0050] Step S2, the plastic bottle is loaded into the sterilization metal mold, and is completely wrapped and sealed by a sterilization cavity of the sterilization metal mold; the sterilization cavity is shaped to adapt to the overall outer contour of the plastic bottle to be treated, and the inner wall of the sterilization cavity is in contact with the outer wall of the plastic bottle;

[0051] Step S3, the sterilization metal mold is heated, and after the temperature of the sterilization metal mold is raised to a first preset temperature (such as 121℃), the sterilization metal mold is kept at the temperature for a preset time (such as 20-30min);

[0052] Step S4, the sterilization metal mold is cooled, and after the temperature of the sterilization metal mold is reduced to a second preset temperature (such as 50℃), the plastic bottle is taken out, and the sterilization is completed.

[0053] In this embodiment, the sterilization effects of the plastic bottles filled with edible oil after sterilization operation by using the high-temperature sterilization process and the existing high-pressure steam sterilization process are compared. The detection results of the number of bacteria on the surface of the plastic bottles are shown in Table 1. Among them, the sterilization metal mold is heated to 121℃ and maintained for 10min. The detection method of the number of bacteria refers to GB4789.2-2022 Determination of Total Number of Bacteria in Food Microorganisms.

[0054] Table 1 Comparison of sterilization effects

[0055]

[0056] From the detection results in Table 1, it can be seen that the sterilization effect of the high-temperature sterilization process in this embodiment is roughly equivalent to that of the existing high-pressure steam sterilization process, that is, it is proved that the high-temperature sterilization process in this embodiment can be used for sterilization treatment of plastic bottles. At the same time, after the high-temperature sterilization process in this embodiment, the appearance of the plastic bottle is basically complete, there is no obvious protruding point and other appearance deformation defects, the plastic bottle is well sealed, can stand normally, and the use function is not affected.

[0057] Further, the sealing detection method of the plastic bottle in step S1 is the extrusion leak detection method. For example, a certain pressure is applied to the continuously moving plastic bottle in line, and then the weight of the plastic bottle before and after is compared to see if there is a significant change. If so, the sealing of the plastic bottle is poor, and there will be leakage and pollution during high-temperature sterilization.

[0058] In the existing high-pressure steam sterilization method, the plastic bottle needs to be heated to 121℃ in a closed pressure vessel by steam or water, and after a certain period of heat preservation, forced cooling is started, and gas is injected for pressure balance during cooling, and gradually slow cooling to normal pressure. Therefore, the combination of pressure vessel, steam generator, air compressor, air valve and other equipment is required. High-temperature steam is used during sterilization, so there will be water residue on the surface of the plastic bottle, which needs to be dried before entering the next process, such as labeling, coding, etc. At the same time, due to the process influence of pressure balance fluctuation in the later cooling process, the plastic bottle needs to be made into a very symmetrical cross-sectional shape, such as circular, square, and in order to resist the influence of plastic softening caused by heating, the wall thickness of the plastic bottle is generally increased, which causes the weight of the plastic bottle to be unable to be reduced. The plastic bottle with an asymmetric shape (i.e. non-circular cross-section plastic bottle) often deforms due to pressure balance problems, such as label sticking due to flat protrusion, unstable standing due to bottle bottom protrusion, and large appearance change affecting aesthetics.

[0059] Compared with the prior art, the high-temperature sterilization process for plastic bottles in the embodiment needs to use a sterilization metal mold and supporting auxiliary equipment, the equipment composition is relatively simple, and high-temperature sterilization can be carried out at normal pressure, replacing the sealed pressure vessel, without the need for compressed air for pressure preservation, and the safety factor is higher. On the other hand, in the high-temperature sterilization process for plastic bottles in the embodiment, the plastic bottle is completely sealed by the sterilization cavity in the sterilization metal mold, and the inner wall of the sterilization cavity contacts the outer wall of the plastic bottle, so the expansion of the plastic bottle and the liquid filled therein under the heating state is constrained by the sterilization cavity, thereby effectively ensuring the appearance form and use function of the plastic bottle. Furthermore, in the high-temperature sterilization process for plastic bottles in the embodiment, when the non-circular cross-section plastic bottle is used, the weight of the plastic bottle can be appropriately reduced under the condition of ensuring the appearance form and use function of the non-circular cross-section plastic bottle, thereby reducing the production cost. Furthermore, in the high-temperature sterilization process for plastic bottles in the embodiment, the plastic bottle is not directly contacted with water vapor, and the surface of the plastic bottle after high-temperature sterilization treatment is basically dry, so the next process such as labeling, coding, etc. can be directly carried out. Finally, the high-temperature sterilization process in the present application is suitable for high-temperature sterilization treatment of plastic bottles with circular or square cross-section, and is also suitable for high-temperature sterilization treatment of non-circular cross-section plastic bottles, and has a wide range of applications.

[0060] Embodiment 2

[0061] To cooperate with the high-temperature sterilization process for plastic bottles in embodiment 1, a high-temperature sterilization system for plastic bottles is provided in the embodiment. The high-temperature sterilization system comprises a sterilization metal mold 1, a heating assembly, a cooling assembly, a temperature sensor, a driving mechanism and a controller.

[0062] The sterilization metal mold 1 has a sterilization chamber 11 inside. The shape of the sterilization chamber 11 is adapted to the overall outer contour of the plastic bottle 1' to be processed. When the plastic bottle 1' is inserted into the sterilization chamber 11, the inner wall of the sterilization chamber 11 contacts the outer wall of the plastic bottle 1.

[0063] In this embodiment, to facilitate the insertion of the plastic bottle 1' into the sterilization chamber 11, the sterilization metal mold 1 is designed with a combined structure, specifically including a first mold 12, a second mold 13, and a bottom mold 14, as shown in the attached figure. Figure 2 As shown. One or more first cavities 121 are formed on the first mold 12 starting from the parting surface of the first mold 12. The shape of the first cavity 121 is consistent with the outer contour of the plastic bottle 1' except for the bottom area, and its bottom is open. One or more second cavities 131 are formed on the second mold 13 starting from the parting surface of the second mold 13. The number of second cavities 131 is equal to the number of first cavities 121. Furthermore, the shape of the second cavity 131 is consistent with the outer contour of the remaining part of the plastic bottle 1' except for the bottom area, and its bottom is open. The upper surface of the bottom mold 14 is shaped to match the outer contour of the bottom area of ​​the plastic bottle 1', and its number is equal to the number of second cavities 131 and the number of first cavities 121.

[0064] Therefore, as attached Figure 2 As shown, when the first mold 12, the second mold 13, and the bottom mold 14 are closed, the parting surface of the first mold 12 and the parting surface of the second mold 13 are in contact. Each first cavity 121 corresponds to a second cavity 131. The bottom mold 14 is located in the lower open area of ​​the combined structure of the first cavity 121 and the second cavity 131 and seals the lower end of the open area of ​​the first cavity 121 and the second cavity 131. The sidewall of the bottom mold 14 is in contact with the first mold 12 and the second mold 13. Thus, the enclosed area of ​​the inner wall of the first cavity 121, the inner wall of the second cavity 131, and the upper surface of the bottom mold 14 constitutes a closed sterilization chamber 11. The shape of the sterilization chamber 11 is adapted to the outer contour of the plastic bottle 1'. That is, the plastic bottle 1' can be placed in the sealed combined structure of the first mold 12, the second mold 13, and the bottom mold 14 without shaking. In other words, the plastic bottle 1' has a similar transitional fit relationship with the first cavity 121, the second cavity 131, and the bottom mold 14.

[0065] For example, as shown in the appendix Figure 4As shown, the plastic bottle 1' is a flat bottle structure (one of the non-circular cross-section special-shaped plastic bottles), and the overall shape is similar to a waist hole, with the thickness being substantially constant and the width gradually increasing from top to bottom. The surfaces on both sides of the flat bottle in the thickness direction are recessed, which are the subsequent labeling areas. To cooperate with the high-temperature sterilization of the flat bottle, seven first cavities 121 are formed on the first mold 12 from the parting surface. The shape of the first cavity 121 is consistent with the outer contour of half of the flat bottle along the thickness direction. Seven second cavities 131 are formed on the second mold 13 from the parting surface. The shape of the second cavity 131 is consistent with the outer contour of the other half of the flat bottle along the thickness direction. There are seven bottom molds 14 in total. The upper surface of each bottom mold 14 is consistent with the outer contour of the bottom area of the flat bottle. After the first mold 12, the second mold 13, and the seven bottom molds 14 are closed, one first cavity 121, one second cavity 131, and one bottom mold 14 correspond and form the complete outer contour of one flat bottle.

[0066] In this embodiment, by designing the sterilization metal mold as a first mold, a second mold, and a bottom mold, on the one hand, the processing difficulty of the metal mold can be reduced, and on the other hand, the processing precision of the sterilization metal mold, especially the processing precision of the sterilization cavity, can be improved, thereby reducing the influence of the sterilization metal mold on the appearance and use function of the plastic bottle.

[0067] The heating assembly is arranged on the sterilization metal mold 1, which is heated by an electric heating method or a heat conduction medium heating method to heat the sterilization metal mold to a first preset temperature for high-temperature sterilization of the plastic bottle 1. Specifically, the heating assembly is mainly arranged on the first mold 12 and the second mold 13 to heat the first mold 12 and the second mold 13, and the bottom mold 14 is heated by contact to make the overall sterilization metal mold 1 reach the first preset temperature (such as 121°C). If the size of the bottom mold 14 is also large, the heating assembly is arranged on the first mold 12, the second mold 13, and the bottom mold 14, respectively.

[0068] For example, when the heating assembly adopts an electric heating method, the heating assembly includes a tubular or rod-shaped electric heating element (such as a silicon-carbon rod), a connecting head, a fixing bracket, and the like.

[0069] To fix the electric heating element, a plurality of first installation holes 122 are formed on the first mold 12. A plurality of second installation holes 132 are formed on the second mold 13. The electric heating element is arranged in the first installation hole 122 and the second installation hole 132, respectively. The connecting head is connected to one end of the electric heating element. If the bottom mold 14 needs to be heated separately, a plurality of bottom mold installation holes are formed on the bottom mold 14. The first installation hole 122, the second installation hole 132, and the bottom mold installation hole can be blind holes or through holes, which can be selected according to actual needs. For example, the first installation hole 122 and the second installation hole 132 are blind holes, and the bottom mold installation hole is a through hole. Figure 3As shown, a plurality of first installation holes 122 are formed on the first mold 12. A plurality of second installation holes 132 are formed on the second mold 13. The bottom mold 14 is not provided with an electric heating element and is not provided with a bottom mold installation hole. The electric heating element generates heat after being powered on, thereby increasing the temperature of the first mold, the second mold and the bottom mold, and achieving high-temperature sterilization of the plastic bottle 1' placed in the first mold, the second mold and the bottom mold.

[0070] In this embodiment, the first installation holes 122 are formed adjacent to the inner wall of the first cavity 121, the second installation holes 132 are formed adjacent to the inner wall of the second cavity 12, and the starting position of the bottom mold installation hole is adjacent to the upper surface of the bottom mold 14, so as to improve the heat conduction efficiency of the sterilization cavity 11 and the plastic bottle 1' after the electric heating element is powered on.

[0071] The fixing support is arranged between the surface of the electric heating element and the inner wall of the first installation hole 122, or between the surface of the electric heating element and the inner wall of the second installation hole 132, or between the surface of the electric heating element and the inner wall of the bottom mold installation hole, so as to provide auxiliary support for the electric heating element and avoid damage during movement of the sterilization metal mold 1.

[0072] In this embodiment, the first installation holes 122 are formed in the length direction of the first mold 12 or in the height direction of the first mold 12. The second installation holes 132 are formed in the length direction of the second mold 13 or in the height direction of the second mold 13. The bottom mold installation hole is formed in the thickness direction of the bottom mold 14.

[0073] When the first installation holes 122 are formed in the length direction of the first mold 12 and the second installation holes 132 are formed in the length direction of the second mold 13, the depth of the first installation holes 122 and the depth of the second installation holes 132 can be respectively equal to the length of the first mold 12 and the length of the second mold 13, and the electric heating element with a length approximately equal to the depth of the first installation holes 122 and the depth of the second installation holes 132 is selected to cover the entire first mold 12 and the entire second mold 13.

[0074] Further, as shown in FIG. 2, the first installation holes 122 are formed in the length direction of the first mold 12, and the second installation holes 132 are formed in the length direction of the second mold 13. Figure 3 As shown, when the first installation holes 122 are formed in the length direction of the first mold 12 and the second installation holes 132 are formed in the length direction of the second mold 13, the axial center of each first installation hole 122 in the height direction of the first mold 12 is approximately equal to the distance from the point on the inner wall of the corresponding first cavity 121, and the axial center of each second installation hole 132 in the height direction of the second mold 13 is approximately equal to the distance from the point on the inner wall of the corresponding second cavity 12. Thus, the first installation holes 122 of the first mold 12 and the second installation holes 132 of the second mold 13 form a region with a shape approximately similar to the outer contour of the plastic bottle 1' in the thickness or width direction.

[0075] When the first installation hole 122 is along the height direction of the first mold 12 and the second installation hole 132 is along the height direction of the second mold 13, the depth of the first installation hole 122 and the depth of the second installation hole 132 are respectively the height of the first mold 12 and the height of the second mold 13, and the electric heating element with the length approximately equal to the depth of the first installation hole 122 and the depth of the second installation hole 132 is selected, so that the selective area is locally heated, for example, when the first cavity 121 on the first mold 12 is used.

[0076] For example, when the heating assembly uses the heat conduction medium to heat, the heating assembly includes a storage tank, a delivery pump and a connecting head.

[0077] The storage tank contains the heat conduction medium (such as heat conduction oil, water), and is provided with an electric heater or a heating jacket layer to heat the heat conduction medium. In order to cooperate with the heat conduction, the first hot runner is arranged on the first mold 12. The first hot runner can be a plurality of parallel straight hot runners or an S-shaped hot runner. The second hot runner is arranged on the second mold 13. The second hot runner can be a plurality of parallel straight hot runners or an S-shaped hot runner. The bottom mold can also be provided with a bottom mold hot runner. The inlet and outlet ends of the first hot runner, the inlet and outlet ends of the second hot runner and the inlet and outlet ends of the bottom mold hot runner are provided with connecting heads and connected with the delivery pump and the storage tank. The heated heat conduction medium in the storage tank is pumped into the first hot runner, the second hot runner and the bottom mold hot runner by the delivery pump, and the first mold, the second mold and the bottom mold are heated by the heat conduction medium, so as to realize the high-temperature sterilization of the plastic bottle 1'. At the same time, the heating assembly on the first mold 12 and the heating assembly on the second mold 13 can share part of the equipment (such as the storage tank and the delivery pump), so as to reduce the equipment purchase cost.

[0078] In the embodiment, the first hot runner is arranged adjacent to the inner wall of the first cavity 121, the second hot runner is arranged adjacent to the inner wall of the second cavity 12, and the bottom mold hot runner is arranged adjacent to the upper surface of the bottom mold 14, so as to improve the heat conduction efficiency of the heat conduction medium to the sterilization cavity 11 and the plastic bottle 1'.

[0079] In the embodiment, in order to avoid heat loss of the sterilization metal mold 1' and prevent scalding, a heat preservation and insulation layer (such as heat preservation and insulation cotton) is laid on the surface of the sterilization metal mold 1'.

[0080] The cooling assembly is arranged on the sterilization metal mold, and is cooled by air cooling or cooling medium heat absorption, so that the temperature of the sterilization metal mold 1 is reduced to a second preset temperature (for example, 50℃). Specifically, the cooling assembly is mainly arranged on the first mold 12 and the second mold 13 to cool the first mold 12 and the second mold 13. The bottom mold 14 is cooled by contact cooling to make the whole sterilization metal mold 1 reach the second preset temperature (for example, 50℃). If the size of the bottom mold 14 is also large, the cooling assembly is arranged on the first mold 12, the second mold 13 and the bottom mold 14 respectively.

[0081] For example, when the cooling assembly adopts air cooling, the cooling assembly includes a fan and a bracket. The bracket is arranged on the first mold 12 and the second mold 13 respectively. The fan is arranged on the bracket. After the fan is powered on, the air flow on the surface of the first mold 12 and the second mold 13 is disturbed to cool. If the surface of the sterilization metal mold 1 is covered with a thermal insulation layer, the thermal insulation layer needs to be opened.

[0082] For another example, when the cooling assembly adopts cooling medium heat absorption, the cooling assembly includes a water tank, a water pump and a connecting head. The water tank contains cooling medium (for example, water with a temperature of 50℃). The cooling medium in the water tank can also be cooled by a fan to maintain a lower temperature. The first mold 12 is provided with a first cooling flow channel 123. The first cooling flow channel 123 can be a plurality of parallel straight flow channels or a S-shaped flow channel. The second mold 13 is provided with a second cooling flow channel 133. The second cooling flow channel 133 can be a plurality of parallel straight flow channels or a S-shaped flow channel. The bottom mold 14 can also be provided with a bottom mold cooling flow channel. The inlet and outlet ends of the first cooling flow channel 123, the inlet and outlet ends of the second cooling flow channel 133 and the inlet and outlet ends of the bottom mold cooling flow channel are respectively provided with connecting heads and connected with the water pump and the water tank.

[0083] In this embodiment, the first cooling flow channel 123 is arranged adjacent to the inner wall of the first cavity 121, the second cooling flow channel 133 is arranged adjacent to the inner wall of the second cavity 12, and the bottom mold cooling flow channel is arranged adjacent to the upper surface of the bottom mold 14, so as to improve the cooling speed.

[0084] In the embodiment, the first cold runner 123 on the first mold 12 and the first mounting hole 122 are arranged alternately, and the second cold runner 133 on the second mold 13 and the second mounting hole 132 are arranged alternately. That is, one first cold runner 123 or a part of the first cold runner 123 is arranged between two first mounting holes 122 in the same direction. One second cold runner 133 or a part of the second cold runner 133 is arranged between two second mounting holes 132 in the same direction. Alternatively, the first cold runner 123 on the first mold 12 and the first hot runner are arranged alternately, and the second cold runner 133 on the second mold 13 and the second hot runner are arranged alternately. Thus, when the heating assembly works for high-temperature sterilization, the cooling assembly can also work to remove part of the heat to prevent the temperature of the plastic bottle 1' from being too high. After high-temperature sterilization, the cooling assembly can quickly work to remove heat and quickly reduce the temperature of the plastic bottle 1'.

[0085] The temperature sensors are arranged on the sterilization metal mold 1, and the probe parts thereof are adjacent to the sterilization cavity 11. Specifically, the temperature sensors are arranged on the first mold 12, the second mold 13, and the bottom mold 14. That is, from top to bottom, the temperature of multiple points of the sterilization cavity 1 is monitored to ensure that the first mold 12, the second mold 13, and the bottom mold 14 reach the first preset temperature during high-temperature sterilization, to avoid damage to the plastic bottle 1' caused by excessively high temperature, and to determine the timing of opening the mold to take out the plastic bottle 1'.

[0086] The driving mechanism is connected with the sterilization metal mold 1 to cooperate to realize opening or closing of the sterilization metal mold 1. Specifically, the driving mechanism provides closing power when the first mold 12, the second mold 13, and the bottom mold 14 are closed, and provides clamping force after the molds are closed to improve the sealing effect after the molds are closed. The driving mechanism can be a pneumatic cylinder or a hydraulic cylinder. The position of the driving mechanism is selected and arranged according to the moving direction and moving requirements between the first mold 12, the second mold 13, and the bottom mold 14.

[0087] For example, when the position of the first mold 12 is fixed, one driving mechanism is connected with the second mold 13, and one driving mechanism is connected with multiple bottom molds 14 through corresponding connecting members. When the molds are closed, the plastic bottle 1' is first clamped into the first cavity 121, and then the second mold 13 and the bottom mold 14 are pushed by the driving mechanism to move towards the first mold 12, so that the plastic bottle 1' is clamped in the sealed combined structure of the first mold 12, the second mold 13, and the bottom mold 14.

[0088] For example, when the position of the first mold 12 is fixed, installation grooves are arranged on the first mold 12 and the corresponding second mold 13. The side wall of the bottom mold 14 is formed with protrusions matched with the installation grooves. When the molds are closed, the non-circular cross-section plastic bottle is first clamped into the first cavity 121 and the bottom mold 14, and then the second mold 13 is moved towards the first mold 12 by the driving mechanism, so that the plastic bottle 1' is clamped in the sealed combination structure of the first mold 12, the second mold 13 and the bottom mold 14.

[0089] For example, the first mold 12, the second mold 13 and the bottom mold 14 are respectively provided with driving mechanisms. When the molds are closed, the plastic bottle 1' is first clamped into the first cavity 121, and then the first mold 12, the second mold 13 and the bottom mold 14 are synchronously moved by the driving mechanisms, so that the plastic bottle 1' is clamped in the sealed combination structure of the first mold 12, the second mold 13 and the bottom mold 14.

[0090] The controller is connected with the heating assembly, the cooling assembly, the temperature sensor and the driving mechanism. The controller is used to receive the temperature signal generated by the temperature sensor and issue work instructions. For example, after the plastic bottle 1' is clamped into the first mold 12, the controller issues an instruction to drive the second mold 13 and the bottom mold 14 to move towards the first mold 12 by the driving mechanism. At the same time, the controller controls the heating assembly to work to heat the first mold 12, the second mold 13 and the bottom mold 14, and when the temperature reaches the first preset temperature of high-temperature sterilization, the temperature is kept. After high-temperature sterilization, the controller issues an instruction to start the cooling assembly, and the heating assembly stops working. When the temperature decreases to the second preset temperature (for example, 50℃), the cooling assembly stops working, the driving mechanism drives the second mold 13 and the bottom mold 14 to move away from the first mold 12 to demold, and the plastic bottle 1' is taken out.

[0091] In the existing high-pressure steam sterilization method, the plastic bottle needs to be heated to 121℃ in a sealed pressure container by steam or water, and after a period of heat preservation, forced cooling is started, and gas is injected for pressure balance during cooling, and gradually slowly cooled to normal pressure. Therefore, the combination of pressure container, steam generator, air compressor, gas valve and other equipment is required. High-temperature steam is used in the sterilization process, so there is water residue on the surface of the plastic bottle, which needs to be dried before entering the next process, such as labeling and coding. At the same time, due to the process influence of pressure balance fluctuation in the later cooling process, the plastic bottle needs to be made into a very symmetrical cross-section shape, such as a circular shape, a square shape, and in order to resist the influence of plastic softening caused by heating, the wall thickness of the plastic bottle is generally increased, which leads to the increase of the weight of the plastic bottle. The plastic bottle with asymmetric shape (i.e. non-circular cross-section plastic bottle) often deforms due to the problem of pressure balance, such as the flat protrusion affecting the labeling, the bottle bottom protrusion standing unstable, the large change of the shape affecting the appearance, and many other problems.

[0092] Compared with the prior art, the high-temperature sterilization system for plastic bottles in the embodiment has the following advantages: on the one hand, the equipment of the high-temperature sterilization system is relatively simple, the high-temperature sterilization can be carried out under normal pressure, the sealed pressure container is replaced, and compressed air is not needed for pressure keeping, so that the safety factor is higher; on the other hand, the plastic bottles in the high-temperature sterilization system are clamped in the sealed combined structure of the first mold, the second mold and the bottom mold, the first mold, the second mold and the bottom mold are heated in a controlled manner by electric heating or heat-conducting medium heating, the internal pressure of the plastic bottles and the liquid in the plastic bottles is offset by the first mold, the second mold and the bottom mold, the internal walls of the first cavity and the second cavity and the upper surface of the bottom mold limit the expansion deformation of the plastic bottles in the heated state, and the appearance and the use function of the plastic bottles are effectively ensured; furthermore, when the high-temperature sterilization system is used for non-circular cross-section special-shaped plastic bottles, the weight of the plastic bottles can be appropriately reduced under the condition of ensuring the appearance and the use function of the non-circular cross-section special-shaped plastic bottles, and the production cost is reduced; furthermore, the plastic bottles in the high-temperature sterilization system are not directly contacted with water vapor, the surface of the plastic bottles is basically dry after high-temperature sterilization, and therefore the next step such as label sticking and code printing can be directly carried out; finally, the high-temperature sterilization system is suitable for high-temperature sterilization of plastic bottles with circular or square cross sections and is also suitable for high-temperature sterilization of non-circular cross-section special-shaped plastic bottles, and the application range is wide.

Claims

1. A high-temperature sterilization process for plastic bottles, characterized in that, The high-temperature sterilization process includes the following steps: Step S1: Perform a sealing test on the filled plastic bottles and discard any plastic bottles that show signs of leakage. Step S2: The plastic bottle is placed into a sterilization metal mold, and the sterilization cavity within the sterilization metal mold completely encloses and seals the plastic bottle; wherein, the shape of the sterilization cavity is adapted to the overall outer contour of the plastic bottle to be processed, and the inner wall of the sterilization cavity is in contact with the outer wall of the plastic bottle, and the expansion of the plastic bottle and the liquid inside it under heating is constrained and limited by the sterilization cavity; Step S3: Heat the sterilized metal mold, and after the temperature of the sterilized metal mold rises to the first preset temperature, keep it warm for a preset time. Step S4: Cool the sterilization metal mold. Once the temperature of the sterilization metal mold has dropped to the second preset temperature, remove the plastic bottle to complete the sterilization process.

2. The high-temperature sterilization process for plastic bottles according to claim 1, characterized in that, The sealing detection method for the plastic bottle in step S1 is the squeeze leak test method.

3. A high-temperature sterilization system for plastic bottles, for implementing the high-temperature sterilization process for plastic bottles as described in claim 1 or 2, characterized in that, The high-temperature sterilization system includes: A sterilization metal mold, wherein the sterilization metal mold has a sterilization chamber; the shape of the sterilization chamber is adapted to the overall outer contour of the plastic bottle to be processed. A heating component is disposed on the sterilization metal mold and is heated by electric heating or heat transfer through a heat-conducting medium to raise the temperature of the sterilization metal mold to a first preset temperature. A cooling component is disposed on the sterilization metal mold, which cools the mold by means of air cooling or heat absorption by a cooling medium, thereby reducing the temperature of the sterilization metal mold to a second preset temperature. Temperature sensors are distributed on the sterilization metal mold, with their probe portions adjacent to the sterilization chamber; A driving mechanism is connected to the sterilization metal mold and works together to open or close the sterilization metal mold. The controller is connected to the heating component, the cooling component, the temperature sensor, and the drive mechanism.

4. The high-temperature sterilization system for plastic bottles according to claim 3, characterized in that, A heat insulation layer is applied to the outer wall of the sterilized metal mold.

5. The high-temperature sterilization system for plastic bottles according to claim 3, characterized in that, The sterilization metal mold includes: A first mold, wherein one or more first cavities are formed from the parting surface; the shape of the first cavity is consistent with the outer contour of the plastic bottle except for the bottom area, and its bottom is open. The second mold has one or more second cavities opened from the parting surface; the number of the second cavities is the same as the number of the first cavities, and their shape is consistent with the outer contour of the remaining part of the plastic bottle except for the bottom area, and their bottom is open; The bottom mold, the number of which is the same as the number of the second cavity, has an upper surface shape that matches the outer contour of the bottom area of ​​the plastic bottle; When the sterilization metal mold is closed, the parting surface of the first mold and the parting surface of the second mold are in contact; each first cavity corresponds to one second cavity, and the bottom mold is located in the lower open area of ​​the combined structure of the first cavity and the second cavity and seals the lower end of the open area of ​​the first cavity and the second cavity; the enclosed area of ​​the inner wall of the first cavity, the inner wall of the second cavity and the upper surface of the bottom mold constitutes the closed sterilization cavity.

6. The high-temperature sterilization system for plastic bottles according to claim 5, characterized in that, When the heating assembly uses an electric heating method, it includes a tubular or rod-shaped electric heating element; the first mold has a plurality of first mounting holes, and the second mold has a plurality of second mounting holes; the electric heating element is respectively disposed in the first mounting holes and the second mounting holes; Alternatively, when the heating component uses a heat transfer medium, it includes a storage tank and a delivery pump; the storage tank contains a heat transfer medium and is equipped with an electric heater or a heating jacket layer; the first mold has a first hot runner, and the second mold has a second hot runner; the first hot runner and the second hot runner are connected to the storage tank and the delivery pump.

7. The high-temperature sterilization system for plastic bottles according to claim 6, characterized in that, When the cooling component is air-cooled, it includes a fan; the fan is disposed on the surface of the sterilization metal mold. Alternatively, when the cooling assembly uses a cooling medium to absorb heat, it includes a water tank and a water pump; the water tank contains a cooling medium; a first cold runner is formed on the first mold, and a second cold runner is formed on the second mold; the first and second cold runners are connected to the water tank and the water pump.

8. The high-temperature sterilization system for plastic bottles according to claim 7, characterized in that, The first mounting hole is provided along the length or height direction of the first mold; the second mounting hole is provided along the length or height direction of the second mold; the first hot runner and the second hot runner are multiple parallel straight hot runners or one S-shaped hot runner; the first cold runner and the second cold runner are multiple parallel straight hot runners or one S-shaped hot runner. And / or, the first mounting hole, the second mounting hole, the first hot runner, the second hot runner, the first cold runner, and the second cold runner are located adjacent to the sterilization chamber; And / or, when the opening directions of the first mounting hole and the second mounting hole are respectively the length directions of the first mold and the second mold, the axial center of each of the first mounting holes in the height direction of the first mold is approximately equal to the distance from the point on the horizontally corresponding inner wall of the first cavity, and the axial center of each of the second mounting holes in the height direction of the second mold is approximately equal to the distance from the point on the horizontally corresponding inner wall of the second cavity.

9. The high-temperature sterilization system for plastic bottles according to claim 7 or 8, characterized in that, The first cold runner and the first mounting hole are alternately arranged, as are the second cold runner and the second mounting hole; the first cold runner and the first hot runner are alternately arranged, as are the second cold runner and the second hot runner.

10. The high-temperature sterilization system for plastic bottles according to any one of claims 6 to 8, characterized in that, The bottom mold is provided with bottom mold mounting holes or bottom mold hot runners, and is equipped with the heating component; the bottom mold is also provided with bottom mold cold runners, and is equipped with the cooling component.

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