Plastic packaging bag heat sealing equipment

Abstract

The invention is suitable for the field of packaging bag heat-sealing equipment, and provides plastic packaging bag heat-sealing equipment which comprises a heat-sealing assembly, a heat-sealing assembly and a heat-sealing assembly. The conveying unit is used for clamping and conveying the plastic packaging bags, and two heat sealing units used for conducting heat sealing on the plastic packaging bags and two cooling units used for cooling the sealing positions of the plastic packaging bags subjected to heat sealing are arranged in the conveying unit; a liquid pump; the heat dissipation unit is used for cooling the fluid flowing through the pipeline; and the rack is fixedly installed at the bottom of the machine shell and used for supporting the heat sealing assembly. The cooling unit, the liquid pump and the heat dissipation unit are combined to form a refrigeration cycle, after heat sealing of the plastic packaging bag is finished, cooling and heat dissipation are conducted on a sealing opening of the plastic packaging bag in time, plastic is rapidly cured, the problem that due to uneven cooling or too low speed, the sealing area shrinks unevenly is solved, and the sealing efficiency is improved. And therefore, the shape and the strength of the seal are ensured.

Description

Technical Field

[0001] The invention belongs to the field of packaging bag heat sealing equipment, and in particular relates to a plastic packaging bag heat sealing equipment. Background Art

[0002] Plastic packaging bags are widely used in the food, pharmaceutical, and daily chemical industries. The reliability and performance of their seals are crucial to product protection. These seals typically prevent oxygen and water vapor penetration, block contaminants, prevent leakage or deterioration of contents, and effectively carry product identification information.

[0003] Existing heat-sealing equipment for plastic packaging bags usually achieves heat sealing based on the core physical process that thermoplastic plastic materials melt and fuse when heated and pressurized, and re-solidify after cooling. The plastic packaging bags are heat-melted and extruded and fused through a hot melt component. However, due to the high temperature environment within the heat-sealing equipment, the plastic packaging bags often cannot be cooled and solidified in time after heat sealing, which makes the plastic bag seals easily damaged and crushed, affecting the sealing effect and shape aesthetics. Summary of the Invention

[0004] The object of the present invention is to provide a heat-sealing device for plastic packaging bags, aiming to solve the problems raised in the background technology.

[0005] The present invention is achieved by providing a heat-sealing device for plastic packaging bags, comprising:

[0006] Heat sealing assembly, comprising:

[0007] a casing, one side of which is fixedly mounted with a guard plate;

[0008] The conveying unit is used to clamp and convey the plastic packaging bags, and is provided with two heat-sealing units for heat-sealing the plastic packaging bags and two cooling units for cooling the sealed portions of the heat-sealed plastic packaging bags. The cooling units are fixedly provided with an S-shaped heat dissipation cavity, in which a heat-conducting fluid flows;

[0009] The liquid pump is fixedly installed in the casing and connected to the heat dissipation cavity through a pipeline;

[0010] Heat dissipation unit, comprising:

[0011] A heat dissipation fan is fixedly mounted on the inner wall of the casing, and a heat dissipation opening for ventilation is fixedly opened on the side wall of the casing at a position corresponding to the heat dissipation fan;

[0012] The heat dissipation pipe is fixedly installed on one side of the heat dissipation fan. It is composed of a copper pipe coiled in an "S" shape. It is connected to the heat dissipation cavity and the liquid pump through a pipe to form a cooling circulation loop, which is used to cool the fluid flowing through the pipe.

[0013] The frame is fixedly installed at the bottom of the casing and is used to support the heat sealing components.

[0014] As a further solution of the present invention: the guard plate includes two side plates and two guide plates, the two side plates and the two guide plates are all formed of one-piece sheet metal, a gap is reserved between the two side plates for the plastic packaging bags to pass through, and the two guide plates are bent to form a trumpet-shaped opening.

[0015] As a further solution of the present invention: the conveying unit includes:

[0016] Two conveying motors, fixedly installed in the casing;

[0017] Four tensioning rollers, each consisting of two sub-rollers fixedly connected by a central axis and mounted vertically in the guard plate. The four tensioning rollers are divided into two groups horizontally. Two extrusion belts are horizontally wound around the outer side of each group of tensioning rollers through parallel sub-rollers. The central axis of the tensioning roller also movably passes through the machine casing and the guard plate. The central axes of the two tensioning rollers are respectively fixedly connected to the power output ends of the two conveying motors;

[0018] Four extrusion seats are fixedly installed in the guard plate and are located on the inner sides of the four extrusion belts in opposite directions. A plurality of extrusion rollers are rotatably installed therein via a central axis. The extrusion seats are in extrusion contact with the extrusion belts through the plurality of extrusion rollers.

[0019] As a further solution of the present invention: the two heat sealing units are fixedly installed between the four extrusion seats in relative directions, and a pressing plate is movably arranged therein, and a second heating wire is fixedly installed in the pressing plate. The outer side of the second heating wire is filled with a second thermal conductive material for limiting and assisting heat conduction. A fixed block is also fixedly arranged in the heat sealing unit, and the fixed block realizes extrusion contact with the plastic packaging bag by squeezing the pressing plate through an extrusion spring fixedly installed on the side.

[0020] As a further solution of the present invention: two preheating units are also provided in the conveying unit, which are fixedly installed between two vertical extrusion seats, and are used to preheat the sealing part of the plastic packaging bag. A distance is reserved from the surface of the sealing part of the plastic packaging bag. A heating wire is fixedly installed in the preheating unit, and the outside of the heating wire is filled with a thermal conductive material for limiting and assisting heat conduction.

[0021] As a further solution of the present invention: an installation groove is fixedly opened at the end of the cooling unit, and a plurality of heat dissipation rollers are rotatably installed in the installation groove through a central axis, and the heat dissipation rollers are in rolling contact with the plastic packaging bag.

[0022] As a further solution of the present invention: the frame includes:

[0023] Two columns, the overall structure of which is set in an "L" shape, with an anti-skid pad fixedly installed at the bottom for anti-skid, and a movable rod is set inside the column through sliding cooperation, and the movable rod is fixedly connected to the bottom of the housing;

[0024] The mounting plate is horizontally arranged and connects the side surfaces of the two columns, on which a nut is fixedly mounted, the nut is mounted with a screw rod through threaded cooperation, a movable head is movably arranged at the end of the screw rod, and the movable head is fixedly connected to the bottom of the casing.

[0025] As a further solution of the present invention: a supporting assembly is horizontally arranged directly below the guard plate, and the supporting assembly is used for assisting the bearing and transportation of the plastic packaging bag, including:

[0026] A mounting base, fixedly mounted on the column, with a drive motor fixedly mounted on its side;

[0027] A plurality of rollers are rotatably mounted in a mounting seat through a central axis, with a conveyor belt wrapped around the outer side thereof. The central axis of one of the rollers passes through the mounting seat and is fixedly connected to the power output end of the drive motor.

[0028] As a further solution of the present invention: a pair of guide guardrails are symmetrically fixedly installed on the mounting seat, and the guide guardrails are formed by bending metal plates. The two ends of the two guide guardrails are trumpet-shaped and open, and the middle part is narrowed and kept parallel.

[0029] The beneficial effects of the present invention are:

[0030] The present invention provides a heat-sealing device for plastic packaging bags. The device forms a refrigeration cycle by combining a cooling unit, a liquid pump, and a heat dissipation unit. After the heat sealing of the plastic packaging bag is completed, the seal of the plastic packaging bag is cooled and dissipated in time, allowing the plastic to solidify quickly. This avoids the problem of uneven shrinkage in the sealing area due to uneven cooling or too slow a speed, which in turn causes wrinkling, blistering, unevenness, or even warping of the seal edge, thereby ensuring the shape and strength of the seal. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The three-dimensional structure of a plastic packaging bag heat sealing device provided by the present invention Figure 1 ;

[0032] Figure 2 The three-dimensional structure of a plastic packaging bag heat sealing device provided by the present invention Figure 2 ;

[0033] Figure 3 The three-dimensional structure of a plastic packaging bag heat sealing device provided by the present invention Figure 3 ;

[0034] Figure 4 A partial cross-sectional schematic diagram of a heat-sealing device for plastic packaging bags provided by the present invention;

[0035] Figure 5 This is a partial structural diagram of the conveying unit of a heat-sealing device for plastic packaging bags provided by the present invention;

[0036] Figure 6 A partial cross-sectional schematic diagram of a conveying unit of a heat-sealing device for plastic packaging bags provided by the present invention;

[0037] Figure 7 for Figure 6 A in the middle is an enlarged schematic diagram;

[0038] Figure 8 for Figure 6 The enlarged schematic diagram of point B in the middle;

[0039] Figure 9 for Figure 6 The enlarged schematic diagram of point C in the middle;

[0040] Figure 10 This is a schematic diagram of the partial structure explosion of the conveying unit of a heat-sealing device for plastic packaging bags provided by the present invention;

[0041] Figure 11 This is a partial structural diagram of a supporting assembly of a plastic packaging bag heat sealing device provided by the present invention.

[0042] In the accompanying drawings: 1 heat sealing assembly, 11 housing, 111 heat dissipation vent, 12 guard plate, 121 side plate, 122 guide plate, 13 conveying unit, 131 conveying motor, 132 tensioning roller, 1321 sub-roller, 133 extrusion belt, 134 extrusion seat, 135 extrusion roller, 14 preheating unit, 141 heating wire 1, 142 thermal conductive mass 1, 15 heat sealing unit, 151 pressing plate, 152 heating wire 2, 153 thermal conductive mass 2, 154 solid Fixed block, 155 extrusion spring, 16 cooling unit, 161 heat dissipation cavity, 162 mounting slot, 163 heat dissipation roller, 17 liquid pump, 18 heat dissipation unit, 181 heat dissipation pipe, 182 cooling fan, 2 racks, 21 columns, 211 anti-slip pad, 22 movable rod, 23 mounting plate, 231 nut, 24 screw, 241 movable head, 3 supporting assembly, 31 mounting seat, 32 drive motor, 33 roller shaft, 34 conveyor belt, 35 guide guardrail. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0044] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0045] See also Figures 1 to 9 The present invention provides a heat-sealing device for plastic packaging bags, comprising:

[0046] Heat sealing assembly 1, comprising:

[0047] The housing 11 has a guard plate 12 fixedly mounted on one side thereof;

[0048] The conveying unit 13 is used to clamp and convey the plastic packaging bags. It is provided with two heat-sealing units 15 for heat-sealing the plastic packaging bags and two cooling units 16 for cooling the sealed portions of the heat-sealed plastic packaging bags. The cooling units 16 are fixedly provided with an S-shaped heat dissipation cavity 161, in which a heat-conducting fluid flows.

[0049] The liquid pump 17 is fixedly installed in the housing 11 and connected to the heat dissipation cavity 161 through a pipeline;

[0050] The heat dissipation unit 18 includes:

[0051] A heat dissipation fan 182 is fixedly mounted on the inner wall of the housing 11, and a heat dissipation vent 111 for ventilation is fixedly opened on the side wall of the housing 11 at a position corresponding to the heat dissipation fan 182;

[0052] The heat dissipation pipe 181 is fixedly mounted on one side of the heat dissipation fan 182 and is formed by a copper pipe coiled in an "S" shape. It is connected to the heat dissipation chamber 161 and the liquid pump 17 through a pipe to form a cooling circulation loop for cooling the fluid flowing through the pipe;

[0053] The frame 2 is fixedly mounted on the bottom of the casing 11 and is used to support the heat sealing assembly 1 .

[0054] In actual application, this embodiment is implemented by clamping the sealed portion of the plastic packaging bag onto the conveying unit 13, and heat-sealing the plastic packaging bag via the heat-sealing unit 15 during the conveying process. The conveying unit 13 continuously transports the plastic packaging bag. When the plastic packaging bag passes through the cooling unit 16, the heat-conducting fluid flowing in the heat dissipation cavity 161 is combined with the cooling unit 16 to absorb the heat from the plastic packaging bag. The heat is then transported to the heat dissipation pipe 181 by the pumping action of the liquid pump 17, and the air flow is driven by the heat dissipation fan 182. The flowing air takes away the heat of the heat-conducting fluid in the heat dissipation pipe 181, and the low-temperature heat-conducting fluid is pumped back into the heat dissipation cavity 161 by the pumping action of the liquid pump 17, thereby forming a refrigeration cycle to achieve continuous cooling of the sealed portion of the plastic packaging bag.

[0055] In this embodiment, a refrigeration cycle is formed by combining the cooling unit 16, the liquid pump 17 and the heat dissipation unit 18. After the heat sealing of the plastic packaging bag is completed, the seal of the plastic packaging bag is cooled and dissipated in time to allow the plastic to solidify quickly, thereby avoiding the problem of uneven shrinkage in the sealing area due to uneven cooling or too slow speed, which may cause wrinkling, blistering, unevenness or even warping of the seal edge, thereby ensuring the shape and strength of the seal.

[0056] See also Figures 2 to 4 As a preferred embodiment of the present invention, the guard plate 12 includes two side plates 121 and two guide plates 122. The two side plates 121 and the two guide plates 122 are both formed of an integral sheet metal. A gap is reserved between the two side plates 121 for the plastic packaging bags to pass through, and the two guide plates 122 are bent to form a trumpet-shaped opening.

[0057] In actual application of this embodiment, the conveying unit 13 is covered and protected by the side panels 121 and the guide plates 122 to avoid potential safety hazards caused by exposed structures. At the same time, the guide plates 122 are trumpet-shaped, which makes it easier for users to guide the plastic packaging bags and further facilitates the heat sealing of the plastic packaging bags.

[0058] See also Figures 4 to 10 As another preferred embodiment of the present invention, the conveying unit 13 includes:

[0059] Two conveying motors 131 are fixedly installed in the housing 11;

[0060] Four tensioning rollers 132, each composed of two sub-rollers 1321 fixedly connected by a central axis and vertically rotatably mounted within the guard plate 12. The four tensioning rollers 132 are divided into two groups horizontally. Two extrusion belts 133 are horizontally wound around the outer side of each group of tensioning rollers 132 via parallel sub-rollers 1321. The central axis of the tensioning roller 132 also movably passes through the housing 11 and the guard plate 12. The central axes of the two tensioning rollers 132 are respectively fixedly connected to the power output ends of the two conveying motors 131;

[0061] Four extrusion seats 134 are fixedly installed in the guard plate 12 and are located on the inner side of the four extrusion belts 133 in a direction relative to each other. Multiple extrusion rollers 135 are installed therein to rotate through the central axis. The extrusion seats 134 are in extrusion contact with the extrusion belts 133 through the multiple extrusion rollers 135.

[0062] In actual application of this embodiment, the conveying motor 131 is provided to drive the tensioning roller 132 to drive the extrusion belt 133 to rotate, and the guide plate 122 guides the plastic packaging bag to be introduced into the space between the extrusion belts 133, and the extrusion roller 135 dynamically squeezes the extrusion belt 133 to achieve the extrusion and fixation of the plastic packaging bag seal. As the extrusion belt 133 rotates, the plastic packaging bag passes through the heat sealing unit 15 and the cooling unit 16 in sequence to complete heat sealing and cooling.

[0063] In this embodiment, the squeezing belt 133 is provided to squeeze and fix the seal of the plastic packaging bag under the squeezing of the squeezing roller 135, and the upper and lower positions of the seal are squeezed and fixed by setting the number of squeezing belts 133. Compared with the positioning device of the existing sealing device, the pressing area is larger and the pressing effect is better. After heat sealing, the flatness of the seal is higher, and at the same time, the sealing effect can be better prevented from being affected by the gravity sagging of the product in the bag.

[0064] See also Figure 6 、 Figure 8 and Figure 10 As another preferred embodiment of the present invention, the two heat sealing units 15 are fixedly installed between the four extrusion seats 134 in relative directions, and a pressing plate 151 is movably provided therein. A second heating wire 152 is fixedly installed in the pressing plate 151, and the outer side of the second heating wire 152 is filled with a second thermal conductive mass 153 for limiting and assisting heat conduction. A fixing block 154 is also fixedly provided in the heat sealing unit 15, and the fixing block 154 squeezes the pressing plate 151 through an extrusion spring 155 fixedly installed on the side to achieve extrusion contact with the plastic packaging bag.

[0065] In actual application of this embodiment, the pressing plate 151 is locally heated by the second heating wire 152 in cooperation with the second thermal conductor 153. Under the elastic extrusion of the extrusion spring 155, the pressing plates 151 in the two oppositely arranged heat sealing units 15 are squeezed onto the surface of the plastic packaging bag. The plastic packaging bag is melted by the heat of the pressing plates 151, and the plastic packaging bag is heat-sealed by the extrusion of the extrusion spring 155.

[0066] In one case of this embodiment, the elasticity of the extrusion spring 155 needs to be debugged multiple times to maintain it within an appropriate range to avoid poor pressing effects due to low extrusion force and to avoid damage to the bag opening after hot melting due to high extrusion force.

[0067] See also Figures 6 and 7As another preferred embodiment of the present invention, two preheating units 14 are further provided in the conveying unit 13, which are respectively fixedly installed between two vertical extrusion seats 134, and are used to preheat the sealing part of the plastic packaging bag. A distance is reserved from the surface of the sealing part of the plastic packaging bag. A heating wire 141 is fixedly installed in the preheating unit 14, and the outside of the heating wire 141 is filled with a thermal conductive mass 142 for limiting and assisting heat conduction.

[0068] In actual application of this embodiment, the preheating unit 14 is locally heated by the provided electric heating wire 141 in conjunction with the thermal conductive mass 142. When the plastic packaging bag is transported by the extrusion belt 133 and passes through the two sides of the preheating unit 14, the heat emitted by the preheating unit 14 preliminarily heats the plastic packaging bag, thereby reducing the temperature requirement of the heat sealing unit 15 and thereby increasing the heat sealing speed.

[0069] See also Figure 9 As another preferred embodiment of the present invention, a mounting groove 162 is fixedly opened at the end of the cooling unit 16, and a plurality of heat dissipation rollers 163 are rotatably installed in the mounting groove 162 through the central axis, and the heat dissipation rollers 163 are in rolling contact with the plastic packaging bag.

[0070] In actual application, this embodiment rotates a plurality of heat dissipation rollers 163 arranged in the mounting groove 162. When a plastic packaging bag passes through, the heat dissipation rollers 163 are in rolling contact with the plastic packaging bag. Under the action of the cooling circulation loop, based on the temperature difference between the heat dissipation rollers 163 and the sealed portion of the plastic packaging bag after heat sealing, heat is transferred to the heat-conducting fluid in the heat dissipation cavity 161, thereby achieving rapid cooling of the sealed portion of the plastic packaging bag. At the same time, based on the rolling contact between the heat dissipation rollers 163 and the plastic packaging bag, damage to the sealed portion of the plastic packaging bag due to extrusion can be further avoided.

[0071] In one case of this embodiment, the cooling unit 16 is made of a material with good thermal conductivity such as copper or aluminum, and thermal conductive glue can be applied to the contact surface between the mounting groove 162 and the heat dissipation roller 163 to improve the heat conduction efficiency.

[0072] See also Figure 2 and Figure 3 As another preferred embodiment of the present invention, the rack 2 includes:

[0073] Two columns 21, whose overall structure is "L"-shaped, with anti-skid pads 211 fixedly installed at the bottom for anti-skid, and movable rods 22 are arranged therein through sliding cooperation, and the movable rods 22 are fixedly connected to the bottom of the housing 11;

[0074] The mounting plate 23 is horizontally arranged and connects the sides of the two columns 21. A nut 231 is fixedly installed on it. The nut 231 is installed with a screw rod 24 through threaded cooperation. The end of the screw rod 24 is movably provided with a movable head 241, and the movable head 241 is fixedly connected to the bottom of the casing 11.

[0075] In actual application of this embodiment, the screw 24 is rotated by a wrench, and the screw 24 moves up and down along the axial direction under the action of the threaded cooperation between the screw 24 and the nut 231. The movable head 241 cooperates with the movable rod 22 movably set in the column 21 to drive the heat sealing assembly 1 to move up and down as a whole for adjustment to adapt to plastic packaging bags of different sizes, thereby improving the applicability of the equipment.

[0076] See also Figures 1 to 4 and Figure 11 As another preferred embodiment of the present invention, a supporting assembly 3 is horizontally arranged directly below the guard plate 12. The supporting assembly 3 is used for assisting the carrying and transportation of the plastic packaging bag, and includes:

[0077] The mounting base 31 is fixedly mounted on the column 21, and a driving motor 32 is fixedly mounted on its side;

[0078] A plurality of rollers 33 are rotatably mounted in the mounting seat 31 via a central axis, with a conveyor belt 34 wound around the outer side thereof. The central axis of one of the rollers 33 passes through the mounting seat 31 and is fixedly connected to the power output end of the drive motor 32 .

[0079] Furthermore, a pair of guide guardrails 35 are symmetrically fixedly mounted on the mounting seat 31 . The guide guardrails 35 are formed by bending metal plates. The two ends of the two guide guardrails 35 are flared in a trumpet shape, and the middle part is narrowed and kept parallel.

[0080] In actual application of this embodiment, the heat sealing assembly 1 is adjusted to a suitable height by the provided screw 24, and the plastic packaging bag is auxiliary supported when the plastic packaging bag is heat-sealed. At the same time, the conveyor belt 34 and the extrusion belt 133 are used to synchronously drive the plastic packaging bag to move, effectively preventing the sealing effect from being affected by the gravity sagging of the product in the bag. In addition, the provided guide guardrail 35 plays a guiding role, effectively preventing the position of the plastic packaging bag from being offset.

[0081] In one case of this embodiment, the conveyor belt 34 and the extrusion belt 133 move at the same linear speed.

[0082] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0083] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0084] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0085] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A heat sealing device for plastic packaging bags, characterized by: include: A heat sealing assembly (1) comprising: A casing (11) having a guard plate (12) fixedly mounted on one side thereof; The conveying unit (13) is used for clamping and conveying plastic packaging bags, and is provided with two heat-sealing units (15) for heat-sealing the plastic packaging bags and two cooling units (16) for cooling the sealed portions of the heat-sealed plastic packaging bags. A heat dissipation cavity (161) coiled in an "S" shape is fixedly provided in the cooling unit (16), and a heat-conducting fluid flows in the heat dissipation cavity (161); A liquid pump (17) is fixedly mounted in the housing (11) and connected to the heat dissipation chamber (161) via a pipeline; The heat dissipation unit (18) comprises: A heat dissipation fan (182) is fixedly mounted on the inner wall of the housing (11), and a heat dissipation opening (111) for ventilation is fixedly opened at a position of the side wall of the housing (11) corresponding to the heat dissipation fan (182); The heat dissipation pipe (181) is fixedly mounted on one side of the heat dissipation fan (182), and is formed by a copper pipe coiled in an S-shape. It is connected to the heat dissipation cavity (161) and the liquid pump (17) through a pipe to form a cooling circulation loop for cooling the fluid flowing through the pipe; The frame (2) is fixedly mounted on the bottom of the casing (11) and is used to support the heat sealing assembly (1).

2. The heat sealing device for plastic packaging bags according to claim 1, characterized in that: The guard plate (12) comprises two side plates (121) and two guide plates (122). The two side plates (121) and the two guide plates (122) are formed of an integral sheet metal. A gap is reserved between the two side plates (121) for the plastic packaging bag to pass through. The two guide plates (122) are bent to form a trumpet-shaped opening.

3. The heat sealing device for plastic packaging bags according to claim 1, characterized in that: The conveying unit (13) comprises: Two conveying motors (131) are fixedly mounted in the housing (11); Four tensioning rollers (132), each of which is composed of two sub-rollers (1321) fixedly connected via a central axis and vertically rotatably mounted in the guard plate (12), the four tensioning rollers (132) being divided into two groups in the horizontal direction, the outer side of each group of tensioning rollers (132) being horizontally wound with two extrusion belts (133) via parallel sub-rollers (1321), the central axis of the tensioning roller (132) also movably passing through the housing (11) and the guard plate (12), wherein the central axes of the two tensioning rollers (132) are respectively fixedly connected to the power output ends of the two conveying motors (131); Four extrusion seats (134) are fixedly installed in the guard plate (12) and are located on the inner sides of the four extrusion belts (133) in opposite directions. A plurality of extrusion rollers (135) are rotatably installed in the four extrusion seats via a central axis. The extrusion seats (134) are in extrusion contact with the extrusion belts (133) via the plurality of extrusion rollers (135).

4. The heat sealing device for plastic packaging bags according to claim 3, characterized in that: The two heat sealing units (15) are fixedly installed between the four extrusion seats (134) in a relative direction, and a pressing plate (151) is movably arranged therein, and a second heating wire (152) is fixedly installed in the pressing plate (151), and the outer side of the second heating wire (152) is filled with a second thermal conductive mass (153) for limiting and assisting heat conduction. A fixed block (154) is also fixedly arranged in the heat sealing unit (15), and the fixed block (154) squeezes the pressing plate (151) through an extrusion spring (155) fixedly installed on the side to achieve extrusion contact with the plastic packaging bag.

5. The heat sealing device for plastic packaging bags according to claim 3, characterized in that: Two preheating units (14) are also provided in the conveying unit (13), which are fixedly installed between two vertical extrusion seats (134) and are used for preheating the sealing part of the plastic packaging bag. A spacing is reserved between the sealing part of the plastic packaging bag. A heating wire (141) is fixedly installed in the preheating unit (14), and the outer side of the heating wire (141) is filled with a heat conductive material (142) for limiting and assisting heat conduction.

6. The heat sealing device for plastic packaging bags according to claim 1, characterized in that: An installation groove (162) is fixedly provided at the end of the cooling unit (16), and a plurality of heat dissipation rollers (163) are rotatably installed in the installation groove (162) via a central axis, and the heat dissipation rollers (163) are in rolling contact with the plastic packaging bag.

7. The heat sealing device for plastic packaging bags according to claim 1, characterized in that: The frame (2) comprises: Two upright columns (21) are provided with an L-shaped overall structure, and a non-slip pad (211) is fixedly installed at the bottom thereof for preventing slipping, and a movable rod (22) is provided therein through sliding cooperation, and the movable rod (22) is fixedly connected to the bottom of the housing (11); The mounting plate (23) is horizontally arranged and connects the sides of the two upright posts (21). A nut (231) is fixedly mounted on the mounting plate. The nut (231) is mounted with a screw rod (24) through threaded engagement. A movable head (241) is movably provided at the end of the screw rod (24). The movable head (241) is fixedly connected to the bottom of the housing (11).

8. The heat-sealing device for plastic packaging bags according to claim 7, characterized in that: A supporting assembly (3) is horizontally arranged directly below the guard plate (12), and the supporting assembly (3) is used for assisting the bearing and transportation of the plastic packaging bag, and comprises: A mounting base (31) is fixedly mounted on the column (21), and a driving motor (32) is fixedly mounted on the side thereof; A plurality of rollers (33) are rotatably mounted in a mounting seat (31) via a central axis, and a conveyor belt (34) is wound around the outer side of the rollers. The central axis of one of the rollers (33) passes through the mounting seat (31) and is fixedly connected to the power output end of the drive motor (32).

9. The heat-sealing device for plastic packaging bags according to claim 8, characterized in that: A pair of guide guardrails (35) are symmetrically fixedly mounted on the mounting seat (31). The guide guardrails (35) are formed by bending metal plates. The two ends of the two guide guardrails (35) are open in a trumpet shape, and the middle part is narrowed and kept parallel.

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