Hot-press sealing equipment for biodegradable plastic bag and sealing method

Abstract

The invention relates to the technical field of food packaging products, in particular to hot-press sealing equipment for biodegradable plastic bags and a sealing method.The hot-press sealing equipment comprises a rack, an air cylinder, a first heat sealing block and a conveying belt, a piston rod is slidably connected into the air cylinder, a sliding table is installed on the rack, a sliding rod is slidably connected to the sliding table, and a second heat sealing block is installed on the lower end face of the sliding rod; the sliding rod is sleeved with a return spring, a transmission assembly is arranged on the machine frame, a transmission rod is arranged on the transmission assembly, the transmission assembly drives the transmission rod to drive the second heat sealing block to press downwards through the lifting force of a piston rod, and a floating block is arranged on the detection assembly and connected to the first heat sealing block in a sliding mode. The detection assembly drives the floating block to conduct air tightness detection on the heat-sealed packaging bag through lifting of the first heat-sealing block, the problem that a large number of unqualified products are produced due to the problems of surface abrasion, impurity accumulation and the like of the first heat-sealing block is solved, and the product percent of pass of the hot-pressing sealing equipment for the biodegradable plastic bag is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of food packaging products, and particularly to a hot-pressing sealing device and a sealing method for biodegradable plastic bags. Background Art

[0002] Biodegradable plastic bags are made of biodegradable materials (such as polylactic acid PLA, polycaprolactone PCL, etc.); the characteristics of these materials are that they can be decomposed into water, carbon dioxide and organic substances through the action of microorganisms under specific environmental conditions, thereby reducing environmental pollution; the basic working principle of a hot-pressing sealing device is to melt the opening part of the plastic bag by heating and pressing, and then solidify it again by cooling to form a firm seal; for example, Chinese Patent CN202121790730.8 discloses a hot-pressing sealing device for biodegradable plastic bags. This solution includes a workbench, on the top of which a concave frame is fixedly connected. An electric cylinder is fixedly installed on the top of the concave frame. The telescopic end of the electric cylinder penetrates through the concave frame and is fixedly connected with a bearing plate. The bottom of the bearing plate is fixedly connected with a connecting plate by screws. This solution clamps and fixes the plastic bag by setting a positioning disk, a chute, a sliding plate, a tension spring and a rubber plate, and hot-presses the plastic bag by setting a concave frame, an electric cylinder, a bearing plate, a connecting plate and a soldering iron; however, there are generally some problems in the prior art. During the operation of the device, the sealing effect of the plastic bag after loading is easily affected by some device factors. When hot-pressing and sealing products with inert gas packaging, such as when there is surface wear and impurity accumulation on the hot-sealing block, the heat received by the bag mouth of the plastic bag is uneven, resulting in a poor sealing effect, and then other air enters the inside of the plastic bag, affecting the shelf life of the product.

[0003] Therefore, aiming at the problem that when hot-pressing and sealing products with inert gas packaging, such as when there is surface wear and impurity accumulation on the hot-sealing block, the heat received by the bag mouth of the plastic bag is uneven, resulting in a poor sealing effect, and then other air enters the inside of the plastic bag, affecting the shelf life of the product, a hot-pressing sealing device and a sealing method for biodegradable plastic bags are proposed. Summary of the Invention

[0004] The purpose of the present invention is to provide a hot-pressing sealing device and a sealing method for biodegradable plastic bags to solve the problem that when hot-pressing and sealing products with inert gas packaging, such as when there is surface wear and impurity accumulation on the hot-sealing block, the heat received by the bag mouth of the plastic bag is uneven, resulting in a poor sealing effect, and then other air enters the inside of the plastic bag, affecting the shelf life of the product.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A hot-pressing sealing device and a sealing method for biodegradable plastic bags, comprising a frame, a cylinder, a first heat-sealing block and a conveyor belt. The cylinder is installed on the frame. A piston rod is coaxially and slidably connected in the cylinder. One end of the piston rod is slidably connected in the cylinder, and the other end is connected to the upper end surface of the first heat-sealing block. A sliding table is installed on the frame. A sliding rod is slidably connected on the sliding table. A second heat-sealing block is installed on the lower end surface of the sliding rod. A return spring with two ends respectively connected to the upper end surface of the sliding table and the upper end surface of the sliding rod is sleeved on the sliding rod. The second heat-sealing block is located below the sliding table. The first heat-sealing block and the second heat-sealing block are connected by a transmission component. A transmission rod is provided on the transmission component. The transmission component transmits the pressure of the rising of the first heat-sealing block to the second heat-sealing block through the transmission rod and drives the second heat-sealing block to move downward. A detection component is also installed on the frame. A floating block is provided on the detection component. The floating block is slidably connected to the first heat-sealing block. The detection component drives the floating block to perform airtightness detection on the heat-sealed packaging bag through the driving force of the lifting and lowering of the first heat-sealing block, avoiding the problem that the decline of the hot-pressing sealing effect caused by surface wear, impurity accumulation, etc. of the first heat-sealing block, and then other air enters the inside of the plastic bag, affecting the product shelf life, and ensuring the qualification rate of the hot-pressing sealing products in the hot-pressing sealing device for biodegradable plastic bags.

[0007] Preferably, the transmission component includes an electromagnetic coil and a pin. The transmission rod includes a driving rod and a driven rod. One end of the driving rod and the driven rod is coaxially hinged on the frame, and the other ends are respectively hinged on the first heat-sealing block and the second heat-sealing block. A locking groove is opened at the hinged end of the driving rod and the driven rod. The locking groove penetrates through the driving rod and the driven rod at the same time. The electromagnetic coil is coaxially installed on the locking groove. The pin is slidably connected in the electromagnetic coil and the locking groove. The electromagnetic coil is electrically connected to the control system. When the first heat-sealing block rises, the control system controls the electromagnetic coil to drive the pin to embed into the locking groove, restricting the rotational freedom between the driving rod and the driven rod. The driving rod drives the driven rod to rotate, so that the second heat-sealing block falls to perform hot-pressing sealing on the bag mouth of the plastic bag. The first heat-sealing block and the second heat-sealing block are connected by a driving rod and a driven rod to complete cross hot-pressing sealing with a power source, avoiding the problem that the decline of the hot-pressing sealing effect caused by surface wear, impurity accumulation, etc. of the first heat-sealing block, and then other air enters the inside of the plastic bag, affecting the product shelf life, and ensuring the qualification rate of the hot-pressing sealing products in the hot-pressing sealing device for biodegradable plastic bags.

[0008] Preferably, the detection assembly includes a support frame, a detection plate and a floating plate, the support frame is installed on the No. 1 heat sealing block and extends above the conveyor belt, a floating groove is provided on one end of the support frame extending above the conveyor belt, the floating block is slidably connected to the floating groove, the detection plate and the floating plate are respectively installed on the upper and lower end surfaces of the floating block, a detection probe is installed on the detection plate, and the detection probe is telecommunication-connected to the control system, during the falling process of the No. 1 heat sealing block, the support frame drives the floating block to move toward the sealed plastic bag, when the buffer pad contacts the pressure surface, the control system controls the detection probe to detect the floating distance of the floating block, thereby avoiding the problem that the surface wear and impurity accumulation of the No. 1 heat sealing block lead to a decrease in the hot pressure sealing effect, and then other air enters the plastic bag, affecting the shelf life of the product, thereby ensuring the qualified rate of the hot pressure sealed products in the hot pressure sealing equipment for biodegradable plastic bags.

[0009] Preferably, the heat-sealing block No. 2 and the heat-sealing block No. 1 have different hot-pressing sealing positions for the plastic bag, and the heat-sealing block No. 2 is offset by a set value in the direction away from the frame compared to the heat-sealing block No. 1, thereby avoiding the problem that the sealing position of the plastic bag fails to be effectively sealed due to the presence of dust and impurities when the heat-sealing block No. 1 performs heat sealing, thereby reducing the air tightness of the plastic bag, thereby ensuring the hot-pressing sealing effect of the hot-pressing sealing equipment for biodegradable plastic bags.

[0010] Preferably, a buffer pad is installed on the lower end surface of the floating plate, and the lower end surface of the buffer pad is recessed upward in a spherical shape. The buffer pad is made of rubber material, which avoids the problem of excessive impact force when the floating plate slides down, causing excessive pressure and damage to the plastic bag, and ensures the stability of the floating plate when it is pressed down in the hot pressure sealing equipment for biodegradable plastic bags. At the same time, the shape of the lower end surface of the buffer pad can also guide and fix the plastic bag.

[0011] Preferably, a detection surface is provided on the lower end surface of the buffer pad, and a pressure surface is provided on the upper end surface of the plastic bag. The area of ​​the detection surface is larger than the pressure surface, thereby avoiding the problem that when the detection surface applies pressure to the pressure surface, the detection surface cannot evenly cover the pressure surface, causing the gas inside the plastic bag to run wild, and then causing the loss of accuracy of the detection data of the detection probe, thereby ensuring the accuracy of the detection data of the detection probe in the hot pressure sealing equipment for biodegradable plastic bags.

[0012] Preferably, the sliding connection surface between the floating groove and the floating block is processed by heat treatment. After processing, the hardness of the sliding connection surface between the floating groove and the floating block is between 50 and 60 HRC. The wear resistance of the sliding connection surface between the floating groove and the floating block is significantly enhanced, and the friction coefficient with the mating parts will also be reduced. This avoids the problem that after the sliding friction between the floating groove and the floating block occurs frequently, the sliding connection surface of the floating groove and the floating block is worn, resulting in the blockage of the sliding of the floating block, and further leading to the loss of the accuracy of the detection data of the detection probe, ensuring the service life of the hot pressing and sealing equipment for biodegradable plastic bags and the accuracy of the detection data of the detection probe.

[0013] The present invention also provides a production process using the above-mentioned hot pressing and sealing equipment for biodegradable plastic bags, which includes the following steps:

[0014] S1: Place the plastic bag after loading: The bag mouth of the plastic bag to be sealed is conveyed to the corresponding sealing position below the hot sealing block through a conveyor belt.

[0015] S2: Start hot pressing and sealing: The control system controls the cylinder to drive the piston rod to slowly press down towards the bag mouth of the plastic bag, so that the first hot sealing block drops at an appropriate speed and contacts the bag mouth of the plastic bag; when pressed to a certain extent, the first hot sealing block applies an appropriate pressure to the plastic bag and maintains the set hot pressing time, and then the control system controls the cylinder to drive the piston rod to slowly lift away from the bag mouth of the plastic bag, so that the first hot sealing block leaves the plastic bag.

[0016] S3: Detect the air tightness of the plastic bag: During the process of the first hot sealing block dropping, the support frame drives the floating block to move towards the plastic bag after sealing. When the buffer pad contacts the pressure receiving surface, the control system controls the detection probe to detect the floating distance of the floating block.

[0017] S4: Secondary sealing: When the detection probe detects that the floating distance of the floating block has changed, the control system controls the electromagnetic coil to drive the pin to embed into the locking groove, restricting the rotational freedom between the active rod and the driven rod. When the first hot sealing block rises, the active rod drives the driven rod to rotate, so that the second hot sealing block drops at an appropriate speed and contacts the bag mouth of the plastic bag; when pressed to a certain extent, the second hot sealing block applies an appropriate pressure to the plastic bag and maintains the set hot pressing time, and then the control system controls the first hot sealing block to press down, so that the second hot sealing block leaves the plastic bag.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. The present invention is provided with a transmission component and a detection component on a frame. A transmission rod is provided on the transmission component. The transmission component transmits the upward force of the first heat-sealing block to the second heat-sealing block through the transmission rod and drives the second heat-sealing block to press down. A floating block is provided on the detection component, and the floating block is slidably connected to the first heat-sealing block. The detection component drives the floating block to lift and lower through the first heat-sealing block to perform airtightness detection on the heat-sealed packaging bag, avoiding the problem of a large number of unqualified products caused by surface wear, impurity accumulation, etc. on the first heat-sealing block, and ensuring the product qualification rate of the hot pressing and sealing equipment for biodegradable plastic bags.

[0020] 2. The present invention adjusts the hot pressing and sealing position of the plastic bag by the second heat-sealing block and the first heat-sealing block. When the second heat-sealing block presses down, it will deviate from the position hot-pressed by the first heat-sealing block before, avoiding the problem that the airtightness of the plastic bag decreases because the sealing position of the plastic bag fails to be effectively sealed due to the presence of dust and impurities when the first heat-sealing block performs heat sealing, and ensuring the hot pressing and sealing effect of the hot pressing and sealing equipment for biodegradable plastic bags.

[0021] 3. The present invention installs a buffer pad on the lower end surface of the floating plate. The lower end surface of the buffer pad is recessed upward in a spherical shape, and the buffer pad is made of rubber material. When the floating plate presses down on the plastic bag that has been hot-pressed by the first hot-pressing block, the buffer pad made of rubber material will buffer the downward force of the floating plate, avoiding the problem that the impact force of the floating plate sliding down is too large, resulting in excessive compression and damage of the plastic bag, ensuring the stability of the floating plate when pressing down in the hot pressing and sealing equipment for biodegradable plastic bags, and at the same time, the shape of the lower end surface of the buffer pad can also guide and fix the plastic bag. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural diagram of the hot pressing and sealing equipment for biodegradable plastic bags of the present invention;

[0023] Figure 2 is a front view of the hot pressing and sealing equipment for biodegradable plastic bags of the present invention;

[0024] Figure 3 is an installation schematic diagram of the hot pressing and sealing equipment for biodegradable plastic bags of the present invention when the first heat-sealing block is lifted and the electromagnetic coil is not triggered;

[0025] Figure 4 is an installation schematic diagram of the hot pressing and sealing equipment for biodegradable plastic bags of the present invention when the first heat-sealing block is lifted and the electromagnetic coil is triggered;

[0026] Figure 5 is a partial structural schematic diagram of the hot pressing and sealing equipment for biodegradable plastic bags of the present invention;

[0027] Figure 6 For the present invention Figure 5 is a partial enlarged view at A in;

[0028] Figure 7 For the present invention Figure 6 is a cross-sectional view taken along line B-B in the present invention;

[0029] Figure 8 is an installation schematic diagram when the electromagnetic coil is triggered in the hot pressing and sealing device for biodegradable plastic bags of the present invention.

[0030] In the figure: 1, frame; 201, cylinder; 202, piston rod; 3, conveyor belt; 4, control system; 501, first heat-sealing block; 502, sliding table; 503, sliding rod; 504, second heat-sealing block; 505, return spring; 6, transmission rod; 601, driving rod; 602, driven rod; 603, electromagnetic coil; 604, pin; 605, locking groove; 701, support frame; 702, detection probe; 703, detection plate; 704, floating block; 705, floating plate; 706, floating groove; 8, buffer pad; 9, detection surface. Detailed implementation manners

[0031] Please refer to Figures 1 to 8 , the present invention provides a hot pressing and sealing device and a sealing method for biodegradable plastic bags, and the technical solutions are as follows:

[0032] A hot-pressing sealing device for biodegradable plastic bags, comprising a frame 1, a cylinder 201, a first heat-sealing block 501, a conveyor belt 3 and a control system 4. The cylinder 201 is installed on the frame 1. A piston rod 202 is coaxially and slidably connected inside the cylinder 201. One end of the piston rod 202 is slidably connected inside the cylinder 201, and the other end is connected to the upper end face of the first heat-sealing block 501. A slide table 502 is installed on the frame 1. A slide rod 503 is slidably connected to the slide table 502. A second heat-sealing block 504 is installed on the lower end face of the slide rod 503. A return spring 505 with two ends respectively connected to the upper end face of the slide table 502 and the upper end face of the slide rod 503 is sleeved on the slide rod 503. The second heat-sealing block 504 is located below the slide table 502. The first heat-sealing block 501 and the second heat-sealing block 504 are connected through a transmission component. A transmission rod 6 is provided on the transmission component. The transmission component transfers the pressure of the rising of the first heat-sealing block 501 to the second heat-sealing block 504 through the transmission rod 6 and drives the second heat-sealing block 504 to move downward. A detection component is also installed on the frame 1. A floating block 704 is provided on the detection component. The floating block 704 is slidably connected to the first heat-sealing block 501. The detection component drives the floating block 704 to perform airtightness detection on the heat-sealed packaging bag through the driving force of the lifting and lowering of the first heat-sealing block 501. When the first heat-sealing block 501 heat-seals the plastic bag, the control system 4 controls the conveyor belt 3 to drive the heat-pressed and sealed plastic bag to be conveyed in the direction below the floating plate 705. When the heat-pressed and sealed plastic bag is conveyed below the floating plate 705, the control system 4 controls the first heat-pressing block to perform the heat-pressing and sealing work on the second plastic bag; during the process of the first heat-sealing block 501 falling, the support frame 701 follows the first heat-sealing block 501 to drive the floating block 704 to move towards the sealed plastic bag. When the buffer pad 8 contacts the pressure-receiving surface, the control system 4 controls the detection probe 702 to detect the floating distance of the floating block 704. When the detection probe 702 detects that the floating distance of the floating block 704 changes, the control system 4 controls the electromagnetic coil 603 to drive the pin 604 to be embedded in the locking groove 605 to limit the rotational freedom between the active rod 601 and the driven rod 602. When the first heat-sealing block 501 rises, the active rod 601 drives the driven rod 602 to rotate, so that the second heat-sealing block 504 falls at an appropriate speed and contacts the plastic bag mouth; at this time, the second heat-sealing block 504 applies a pressure of 0.2 MPa to the plastic bag and maintains a heat-pressing time of 3 seconds. Then the control system 4 controls the first heat-sealing block 501 to press down, so that the second heat-sealing block 504 leaves the plastic bag, completing the secondary sealing, avoiding the problems such as surface wear and impurity accumulation of the first heat-sealing block 501 resulting in the decline of the heat-pressing and sealing effect, and further resulting in other air entering the plastic bag interior, affecting the product shelf life, and ensuring the qualification rate of the heat-pressed and sealed products in the hot-pressing sealing device for biodegradable plastic bags.

[0033] Please refer to Figures 1 to 8, The transmission assembly includes an electromagnetic coil 603 and a pin 604. The transmission rod 6 includes a driving rod 601 and a driven rod 602. One end of the driving rod 601 and the driven rod 602 are coaxially hinged to the frame 1, and the other ends are respectively hinged to the first heat-sealing block 501 and the second heat-sealing block 504. A locking groove 605 is formed at the hinged end of the driving rod 601 and the driven rod 602. The locking groove 605 penetrates through the driving rod 601 and the driven rod 602 at the same time. The electromagnetic coil 603 is coaxially installed on the locking groove 605. The pin 604 is slidably connected in the electromagnetic coil 603 and the locking groove 605. The electromagnetic coil 603 is electrically connected to the control system 4. When the first heat-sealing block 501 rises, the control system 4 controls the electromagnetic coil 603 to drive the pin 604 to embed into the locking groove 605, restricting the rotational freedom between the driving rod 601 and the driven rod 602. The driving rod 601 drives the driven rod 602 to rotate, causing the second heat-sealing block to drop and thermally press-seal the mouth of the plastic bag. The first heat-sealing block 501 and the second heat-sealing block 504 are connected to the same power source through the driving rod 601 and the driven rod 602 to complete cross thermal press-sealing. And this action is collected by the detection probe 702 in the detection assembly and then controlled by the control system 4 after judgment, avoiding problems such as surface wear and impurity accumulation on the first heat-sealing block 501 that lead to a decline in the thermal press-sealing effect, and then other air entering the inside of the plastic bag, affecting the product shelf life, and ensuring the qualification rate of the thermally press-sealed products in the thermal press-sealing equipment for biodegradable plastic bags.

[0034] It should be noted that the thermal press-sealing positions of the second heat-sealing block 504 and the first heat-sealing block 501 on the plastic bag are different. The second heat-sealing block 504 is offset 2 cm away from the frame 1 compared to the first heat-sealing block 501, avoiding the problem that the plastic bag sealing position fails to be effectively sealed due to the presence of dust and impurities during the heat-sealing of the first heat-sealing block 501, resulting in a decrease in the airtightness of the plastic bag, and ensuring the thermal press-sealing effect of the thermal press-sealing equipment for biodegradable plastic bags.

[0035] Please refer to Figures 1 to 6, the detection component includes a support frame 701, a detection plate 703 and a floating plate 705. The support frame 701 is installed on the first heat-sealing block 501 and extends above the conveyor belt 3. A floating groove 706 is formed at one end of the support frame 701 extending above the conveyor belt 3. A floating block 704 is slidably connected to the floating groove 706. The detection plate 703 and the floating plate 705 are respectively installed on the upper and lower end faces of the floating block 704. A detection probe 702 is installed on the detection plate 703. The detection probe 702 is electrically connected to the control system 4. The sliding connection surface between the floating groove 706 and the floating block 704 is processed by heat treatment. After processing, the hardness of the sliding connection surface between the floating groove 706 and the floating block 704 is 58HRC. The wear resistance of the sliding connection surface between the floating groove 706 and the floating block 704 is significantly enhanced, and the friction coefficient with the mating parts will also be reduced. During the downward movement of the first heat-sealing block 501, the support frame 701 drives the floating block 704 to move towards the direction of the plastic bag after sealing. When the buffer pad 8 contacts the pressure-receiving surface, the control system 4 controls the detection probe 702 to detect the floating distance of the floating block 704, and transmits the detection result into the control system 4, and determines whether the electromagnetic coil 603 is triggered, avoiding the problems that the surface wear, impurity accumulation, etc. of the first heat-sealing block 501 lead to the decline of the hot-pressing sealing effect, and then other air enters the interior of the plastic bag, affecting the product shelf life, and ensuring the qualification rate of the hot-pressing sealed products in the hot-pressing sealing equipment for biodegradable plastic bags.

[0036] It should be noted that a buffer pad 8 is installed on the lower end face of the floating plate 705. The lower end face of the buffer pad 8 is recessed upward in a spherical shape. The buffer pad 8 is made of rubber material, avoiding the problem that the impact force of the downward sliding of the floating plate 705 is too large, resulting in excessive compression damage to the plastic bag, ensuring the stability of the floating plate 705 when pressing down in the hot-pressing sealing equipment for biodegradable plastic bags, and at the same time, the shape of the lower end face of the buffer pad 8 can also guide and fix the plastic bag.

[0037] It is also worth noting that a detection surface 9 is provided on the lower end face of the buffer pad 8, and a pressure-receiving surface is provided on the upper end face of the plastic bag. The area of the detection surface 9 is larger than that of the pressure-receiving surface, avoiding the problem that when the detection surface 9 presses on the pressure-receiving surface, the detection surface 9 cannot evenly cover the pressure-receiving surface, resulting in the chaotic flow of the gas inside the plastic bag, and then the loss of the accuracy of the detection data of the detection probe 702, and ensuring the accuracy of the detection data of the detection probe 702 in the hot-pressing sealing equipment for biodegradable plastic bags.

[0038] During operation, please refer to Figures 1 to 8, the conveyor belt 3 conveys the mouth of the plastic bag to be sealed to the corresponding sealing position below the heat-sealing block; the control system 4 controls the air cylinder 201 to drive the piston rod 202 to slowly press down towards the mouth of the plastic bag, so that the first heat-sealing block 501 falls at an appropriate speed and contacts the mouth of the plastic bag; when pressed down to a certain extent, the first heat-sealing block 501 applies a pressure of 0.2 MPa to the plastic bag and maintains a hot-pressing time of 3 seconds, and then the control system 4 controls the air cylinder 201 to drive the piston rod 202 to slowly lift away from the mouth of the plastic bag, so that the first heat-sealing block 501 leaves the plastic bag; after the first heat-sealing block 501 seals the plastic bag, the control system 4 controls the conveyor belt 3 to drive the hot-pressed and sealed plastic bag to be conveyed towards the lower part of the floating plate 705. When the hot-pressed and sealed plastic bag is conveyed to the lower part of the floating plate 705, the control system 4 controls the first hot-pressing block to perform the hot-pressing and sealing work on the second plastic bag; during the process of the first heat-sealing block 501 falling, the support frame 701 drives the floating block 704 to move towards the sealed plastic bag. When the buffer pad 8 contacts the pressure-receiving surface, the control system 4 controls the detection probe 702 to detect the floating distance of the floating block 704; when the detection probe 702 detects that the floating distance of the floating block 704 changes, the control system 4 controls the electromagnetic coil 603 to drive the pin 604 to embed into the anti-lock groove 605, restricting the rotational freedom between the active rod 601 and the driven rod 602. When the first heat-sealing block 501 rises, the active rod 601 drives the driven rod 602 to rotate, so that the second heat-sealing block 504 falls and contacts the mouth of the plastic bag; at this time, the second heat-sealing block 504 applies a pressure of 0.2 MPa to the plastic bag and maintains a hot-pressing time of 3 seconds, and then the control system 4 controls the first heat-sealing block 501 to press down, so that the second heat-sealing block 504 leaves the plastic bag, completing the secondary sealing, avoiding problems such as surface wear and impurity accumulation of the first heat-sealing block 501 that lead to a decline in the hot-pressing and sealing effect, and further causing other air to enter the plastic bag, affecting the product shelf life, and ensuring the qualification rate of the hot-pressed and sealed products in the hot-pressing and sealing equipment for biodegradable plastic bags.

[0039] It should be noted that the buffer pad 8 is made of rubber material, avoiding the problem that the impact force of the sliding of the floating plate 705 is too large, resulting in excessive compression and damage of the plastic bag, ensuring the stability of the floating plate 705 when pressing down in the hot-pressing and sealing equipment for biodegradable plastic bags, and at the same time, the shape of the lower end surface of the buffer pad 8 can also guide and fix the plastic bag.

[0040] It is also worth noting that the area of the detection surface 9 is larger than the pressure-receiving surface, avoiding the problem that when the detection surface 9 presses on the pressure-receiving surface, the detection surface 9 cannot evenly cover the pressure-receiving surface, resulting in the chaotic flow of the gas inside the plastic bag, and further causing the loss of the accuracy of the detection data of the detection probe 702, and ensuring the accuracy of the detection data of the detection probe 702 in the hot-pressing and sealing equipment for biodegradable plastic bags.

[0041] The above has described in detail a specific embodiment of the present invention in conjunction with the accompanying drawings, but the present invention is not limited to the described embodiment. For those skilled in the art, without departing from the principles and ideas of the present invention, various changes, modifications, substitutions, and variations made to these embodiments should still fall within the protection scope of the present invention.

Claims

1. A hot-pressing sealing device for biodegradable plastic bags, characterized in that, It includes a frame (1), a cylinder (201), a first heat-sealing block (501) and a conveyor belt (3). The cylinder (201) is installed on the frame (1). A piston rod (202) is coaxially and slidably connected inside the cylinder (201). One end of the piston rod (202) is slidably connected inside the cylinder (201), and the other end is connected to the upper end surface of the first heat-sealing block (501). A slide table (502) is installed on the frame (1). A slide bar (503) is slidably connected to the slide table (502). A second heat-sealing block (504) is installed on the lower end surface of the slide bar (503). A return spring (505) with both ends respectively connected to the upper end surface of the slide table (502) and the upper end surface of the slide bar (503) is sleeved on the slide bar (503). The second heat-sealing block (504) is located below the slide table (502). The first heat-sealing block (501) and the second heat-sealing block (504) are connected by a transmission assembly. A transmission rod (6) is provided on the transmission assembly. The transmission assembly transmits the pressure of the upward movement of the first heat-sealing block (501) to the second heat-sealing block (504) through the transmission rod (6) and drives the second heat-sealing block (504) to move downward. A detection assembly is also installed on the frame (1). A floating block (704) is provided on the detection assembly. The floating block (704) is slidably connected to the first heat-sealing block (501). The detection assembly drives the floating block (704) to perform airtightness detection on the heat-sealed packaging bag by the driving force of the upward and downward movement of the first heat-sealing block (501).

2. A hot pressing and sealing device and sealing method for biodegradable plastic bags according to claim 1, characterized in that: The transmission assembly includes an electromagnetic coil (603) and a pin (604). A control system (4) is installed on the housing. The transmission rod (6) includes a driving rod (601) and a driven rod (602). One end of the driving rod (601) and the driven rod (602) are coaxially hinged to the frame (1), and the other ends are respectively hinged to the first heat-sealing block (501) and the second heat-sealing block (504). A locking groove (605) is formed at the hinged end of the driving rod (601) and the driven rod (602). The locking groove (605) penetrates through both the driving rod (601) and the driven rod (602). The electromagnetic coil (603) is coaxially installed on the locking groove (605). The pin (604) is slidably connected inside the electromagnetic coil (603) and the locking groove (605). The electromagnetic coil (603) is electrically connected to the control system (4).

3. A hot pressing and sealing device and a sealing method for biodegradable plastic bags according to claim 2, characterized in that: The detection component includes a support frame (701), a detection plate (703), and a floating plate (705). The support frame (701) is installed on the first heat-sealing block (501) and extends above the conveyor belt (3). A floating groove (706) is formed at one end of the support frame (701) extending above the conveyor belt (3). The floating block (704) is slidably connected to the floating groove (706). The detection plate (703) and the floating plate (705) are respectively installed on the upper and lower end faces of the floating block (704). A detection probe (702) is installed on the detection plate (703), and the detection probe (702) is in telecommunication connection with the control system (4).

4. A hot pressing and sealing device and a sealing method for a biodegradable plastic bag according to claim 3, characterized in that: The heat-pressing and sealing positions of the second heat-sealing block (504) and the first heat-sealing block (501) on the plastic bag are different. The second heat-sealing block (504) is offset by a set value in a direction away from the machine frame (1) compared to the first heat-sealing block (501).

5. A hot pressing and sealing device and sealing method for biodegradable plastic bags according to claim 3, characterized in that: A buffer pad (8) is installed on the lower end face of the floating plate (705). The lower end face of the buffer pad (8) is recessed upward in a spherical shape, and the buffer pad (8) is made of rubber material.

6. A hot pressing and sealing device and a sealing method for a biodegradable plastic bag according to claim 5, characterized in that: A detection surface (9) is provided on the lower end face of the buffer pad (8), and a pressure-receiving surface is provided on the upper end face of the plastic bag. The area of the detection surface (9) is larger than that of the pressure-receiving surface.

7. A hot pressing and sealing device and a sealing method for biodegradable plastic bags according to claim 6, characterized in that: The sliding connection surface between the floating groove (706) and the floating block (704) is processed by heat treatment. After processing, the hardness of the sliding connection surface between the floating groove (706) and the floating block (704) is between 50 and 60 HRC.

8. A hot pressing and sealing method for biodegradable plastic bags, characterized in that: A heat-pressing and sealing method for a heat-pressing and sealing device for biodegradable plastic bags according to any one of claims 1 to 7 includes the following steps: S1: Place the plastic bag filled with materials: The bag mouth of the plastic bag to be sealed is conveyed to the corresponding sealing position below the heat-sealing block (501) through the conveyor belt (3). S2: Start heat-pressing and sealing: The control system (4) controls the air cylinder (201) to drive the piston rod (202) to slowly press downward toward the bag mouth of the plastic bag, so that the first heat-sealing block (501) drops at an appropriate speed and contacts the bag mouth of the plastic bag; at this time, the first heat-sealing block (501) applies an appropriate pressure to the plastic bag and maintains a set heat-pressing time, and then the control system (4) controls the air cylinder (201) to drive the piston rod (202) to slowly lift away from the bag mouth of the plastic bag, so that the first heat-sealing block (501) leaves the plastic bag. S3: Detect the air tightness of the plastic bag: During the process of the first heat-sealing block (501) dropping, the support frame (701) drives the floating block (704) to move toward the plastic bag after sealing. When the buffer pad (8) contacts the pressure-receiving surface, the control system (4) controls the detection probe (702) to detect the floating distance of the floating block (704). S4: Secondary Sealing: When the detection probe (702) detects a change in the floating distance of the floating block (704), the control system (4) controls the electromagnetic coil (603) to drive the pin (604) to embed into the locking groove (605), restricting the rotational freedom between the active rod (601) and the driven rod (602). When the first heat-sealing block (501) rises, the active rod (601) drives the driven rod (602) to rotate, causing the second heat-sealing block (504) to fall at an appropriate speed and contact the mouth of the plastic bag. At this time, the second heat-sealing block (504) applies an appropriate pressure to the plastic bag and maintains the set hot-pressing time. Then, the control system (4) controls the first heat-sealing block (501) to press down, causing the second heat-sealing block (504) to leave the plastic bag.

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