Straw production system and straw production method

Abstract

The present invention relates to a straw production system and method. The production system includes an extrusion device, a vacuum forming device, and a crystallization device connected in sequence. The extrusion device is provided with a straw extrusion mold, and the vacuum forming device includes a vacuum water tank and a straw forming mold provided on the vacuum water tank. The production system also includes a suction and blowing device, which includes a valve unit, an in-mold channel, and a blowing device and an exhaust device respectively connected to the in-mold channel, wherein the in-mold channel is provided in the straw extrusion mold. After passing through the straw extrusion mold and the straw forming mold, the material is formed into a tubular structure. The in-mold channel is connected to the tubular structure, and the blowing device can assist in straw forming, or the exhaust device can be used to exhaust air into the tubular structure. Compared with the prior art, the present invention can effectively solve the problems of odor and / or poor heat resistance in the production process of straws using biodegradable materials as raw materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of straw molding, and in particular relates to a straw deodorization and crystallization treatment one-step molding production system and method. Background Art

[0002] As food-grade disposable items, straws have high food safety requirements, including odor and resistance to hot water use. Therefore, during the straw production process, different processing methods must be adopted according to the different raw materials. Currently, polypropylene plastic straws are common on the market. They are easy to process, have good hot water resistance after one-step molding, and have a low odor. They are usually produced by air blowing and cold water cooling. Although these plastic products have excellent performance and low prices, they cause serious pollution to the human living environment. With the increasing awareness of environmental protection, some biodegradable materials have become the focus of research and development and attention of many companies in recent years.

[0003] However, straws made from biodegradable materials can have odor and / or poor heat resistance due to their inherent properties. For example, PLA (polylactic acid) straws have a low odor but low initial crystallinity and a low thermal softening point, making them unusable in hot liquids. Similarly, straws made from PBS (polybutylene succinate) and PGA (polyglycolic acid) have a strong odor and are not resistant to hot water. Summary of the Invention

[0004] The purpose of the present invention is to provide a straw production system and a straw production method, which are used to solve the problem that the product has odor and / or poor heat resistance in the straw preparation process using biodegradable materials as raw materials.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A straw production system includes an extrusion device, a vacuum forming device and a crystallization device connected in sequence; the extrusion device is provided with a straw extrusion die,

[0007] The vacuum forming device includes a vacuum water tank and a straw forming mold arranged on the vacuum water tank;

[0008] The straw production system further includes a blowing and exhausting device, which includes a valve unit, an in-mold channel, and a blowing device and an exhausting device respectively connected to the in-mold channel; the in-mold channel is provided in the straw extrusion die, and the valve unit is used to connect the in-mold channel to the blowing device, or to connect the in-mold channel to the exhausting device;

[0009] During the production process, the material is formed into a tubular structure after passing through a straw extrusion mold and a straw forming mold. The in-mold channel is connected to the tubular structure, so that when the blowing equipment is working, gas is generated in the center of the tubular structure to facilitate the forming of the tubular structure; when the exhaust equipment is working, negative pressure is generated to remove the waste gas generated in the tube during processing; the vacuum water tank can not only remove the waste gas generated outside the tube, but also balance the pressure inside and outside the tubular structure, thereby preventing the straw from shrinking and breaking due to the negative pressure generated by the exhaust equipment.

[0010] Furthermore, the blowing and exhausting device also includes a blowing pipe and an exhaust pipe, the valve unit includes a three-way valve, the in-mold channel, blowing pipe, and exhaust pipe are all connected to the three-way valve, the blowing equipment is connected to the blowing pipe, and the exhaust equipment is connected to the exhaust pipe.

[0011] As an optional technical solution, the valve unit includes two two-way valves, and the in-mold channel, blowing pipe, and exhaust pipe are connected through a three-way joint, and two-way valves are respectively provided on the blowing pipe and the exhaust pipe to control the connectivity between the blowing equipment, the exhaust equipment and the in-mold channel.

[0012] As a preferred technical solution, both the three-way valve and the two-way valve can be ordinary gas valves.

[0013] Furthermore, the air blowing pipeline is provided with a first gas flow meter and a first gas volume control valve, and the air exhaust pipeline is provided with a second gas flow meter and a second gas volume control valve.

[0014] As a preferred technical solution, the air blowing pipe is further provided with a positive pressure gauge, and the air exhaust pipe is further provided with a negative pressure gauge. The range of the positive and negative pressure gauges is preferably 50-100 Pa.

[0015] Furthermore, the vacuum forming apparatus includes a water circulation assembly comprising a return pipe, a water supply device, and a water inlet pipe, which are sequentially connected to the vacuum water tank in a circular manner. The water inlet pipe is provided with a water flow regulating valve. The water circulation assembly is also used to provide a water environment in the vacuum water tank to cool the straw.

[0016] Furthermore, the vacuum forming device also includes a slow flow tube connected to the water supply device, the end of the tube wall of the slow flow tube is in contact with the outer wall of the straw forming mold, and the water outlet of the slow flow tube points to the edge of the material inlet of the straw forming mold. On the one hand, the outflowing water flow can initially cool the straw so that the straw has a certain stiffness and does not deform. On the other hand, the water flow out of the slow flow tube also produces a liquid sealing effect on the gap between the material and the material inlet of the straw forming mold.

[0017] Furthermore, the end of the slow-flow pipe is in a shovel-shaped structure, and the cross-section of the water outlet gradually increases along the direction of the water flow.

[0018] Furthermore, the water outlet of the slow flow pipe is located 0.4 to 0.8 cm above the material inlet of the straw forming mold.

[0019] As an optimal technical solution, the slow-flow pipe is a stainless steel square tube, and the end of the stainless steel square tube is a shovel-shaped structure. The slow-flow pipe is a stainless steel square tube, which is convenient for processing its end to form a shovel-shaped structure.

[0020] Furthermore, the vacuum forming device further comprises a negative pressure assembly, wherein the negative pressure assembly comprises a vacuum pump, a vacuum pipe connecting the vacuum pump and a vacuum water tank, and a liquid seal box connected to the vacuum pump;

[0021] A first pressure gauge is provided above the vacuum water tank, a second pressure gauge is provided on the vacuum pipe, and a third pressure gauge is provided above the liquid seal box.

[0022] Furthermore, the crystallization device includes a crystallization hot water tank, a heating water tank, and a circulation pump that are cyclically connected; the crystallization hot water tank is provided with a material inlet and a material outlet.

[0023] As an optimal technical solution, the crystallization hot water tank and the heating water tank are made of food-grade stainless steel. The crystallization hot water tank and the heating water tank are connected to realize the hot water circulation function. The crystallization hot water tank is provided with a temperature probe to stabilize the overall temperature and an insulation device is installed on the outer layer to save energy.

[0024] A straw production method based on the above system comprises:

[0025] At the start of operation, the blowing device assists the material in forming into a tubular structure;

[0026] During the operation transition phase, the water level of the vacuum water tank is controlled to gradually rise until the tubular structure is submerged in water, and then the vacuum water tank is evacuated;

[0027] During a stable operation phase, air is extracted into the tubular structure through the air extraction device.

[0028] Compared with the prior art, the present invention has the following characteristics:

[0029] 1) The present invention provides an in-mold channel within the straw extrusion mold, and connects both the blowing device and the exhaust device to the in-mold channel, so that when the blowing device is in operation, gas can be generated in the center of the extruded material to facilitate the molding of the tubular structure; when the exhaust device is in operation, negative pressure is generated to remove odors generated by the processed plastic from the inside of the straw, thereby avoiding secondary processing and deodorization of the straw; at the same time, the straw is further cooled and shaped in a vacuum water tank, which can remove waste gas generated outside the tube on the one hand, and balance the pressure inside and outside the tubular structure on the other hand, thereby avoiding shrinkage and breakage of the straw due to the negative pressure generated by the exhaust device.

[0030] 2) The present invention can solve the problem of straws made of various materials that require post-crystallization treatment by providing an extrusion device, a vacuum forming device and a crystallization device connected in sequence, and can achieve hot water resistance by forming the straws in one step.

[0031] 3) The present invention can be applied not only to air blowing molding but also to vacuum molding. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the structure of a straw production system in the embodiment;

[0033] Description of the marks in the figure:

[0034] 1-Straw extrusion die;

[0035] 2- Vacuum forming device,

[0036] 201- vacuum water tank, 202- straw forming mold, 203- return pipe, 204- water supply device, 205- water inlet pipe, 206- slow flow pipe, 207- vacuum pump, 208- vacuum pipeline, 209- liquid seal box;

[0037] 3-Crystallization device,

[0038] 301-crystallization hot water tank, 302-heating water tank, 303-circulation pump;

[0039] 4-Suction and blowing device,

[0040] 401-in-mold channel, 402-blowing equipment, 403-exhaust equipment, 404-blowing pipeline, 405-exhaust pipeline. DETAILED DESCRIPTION

[0041] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are implemented based on the above technical solution of the present invention, and provide detailed implementation methods and specific operating processes, but the protection scope of the present invention is not limited to the following embodiments.

[0042] It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more elements can be interposed therebetween. When an element is described as being "connected to" another element, it can be directly connected to the other element, or one or more elements can be interposed therebetween. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this specification are for illustrative purposes only. The term "and / or" used in this specification includes any and all combinations of one or more of the relevant listed items.

[0043] like Figure 1 The straw production system shown includes an extrusion device, a vacuum forming device 2, and a crystallization device 3 connected in sequence. The extrusion device is provided with a straw extrusion die 1. The vacuum forming device 2 includes a vacuum water tank 201 capable of providing a negative pressure environment, and a straw forming die 202 disposed on the vacuum water tank 201.

[0044] The straw production system further includes a blowing and exhausting device 4, which includes a valve unit, an in-mold channel 401, and a blowing device 402 and an exhaust device 403 respectively connected to the in-mold channel 401. The in-mold channel 401 is disposed in the straw extrusion die 1, and the valve unit is used to connect the in-mold channel 401 with the blowing device 402, or connect the in-mold channel 401 with the exhaust device 403.

[0045] During the production process, the material is formed into a tubular structure after passing through the straw extrusion mold 1 and the straw forming mold 202. The in-mold channel 401 is connected to the tubular structure, so that when the blowing device 402 is working, gas is generated in the center of the extruded material to facilitate the forming of the tubular structure (the starting stage of operation); when the exhaust device 403 is working, negative pressure is generated to remove the waste gas generated in the tube during processing, and the straw is further cooled and shaped in the vacuum water tank 201 (the stable stage of operation); the vacuum water tank 201 can remove the waste gas generated outside the tube on the one hand, and on the other hand, it can balance the pressure inside and outside the tubular structure to avoid the straw shrinking and breaking due to the negative pressure generated by the exhaust device 403.

[0046] In some specific embodiments, the blowing and suction device 4 further includes a blowing pipe 404 and a suction pipe 405 , the blowing device 402 is connected to the blowing pipe 404 , and the suction device 403 is connected to the suction pipe 405 .

[0047] Preferably, the valve unit includes a three-way valve, which connects the in-mold channel 401, the blowing pipe 404, and the exhaust pipe 405. In another embodiment, the in-mold channel 401, the blowing pipe 404, and the exhaust pipe 405 are connected by a three-way joint, and two-way valves are respectively provided on the blowing pipe 404 and the exhaust pipe 405 to control the communication between the blowing pipe 404 and the exhaust pipe 405 and the in-mold channel 401. More specifically, both the three-way valve and the two-way valve can be ordinary air valves.

[0048] In some specific embodiments, the in-mold channel 401 extends from the discharge end of the straw extrusion mold 1, and the extended end is located in the annular extrusion discharge port of the straw extrusion mold 1, so that the in-mold channel 401 is connected to the interior of the tubular structure, and the extension direction of the in-mold channel 401 is consistent with the discharge direction of the tubular structure, so that the airflow direction of the in-mold channel 401 is parallel to the tubular structure.

[0049] In some specific embodiments, the blowing pipe 404 is provided with a first gas flow meter and a first gas volume control valve, and the exhaust pipe 405 is provided with a second gas flow meter and a second gas volume control valve.

[0050] In some specific embodiments, a positive pressure gauge is provided on the air blowing pipe 404, and a negative pressure gauge is provided on the air exhaust pipe 405. The range of the positive pressure gauge and the negative pressure gauge is preferably 50-100 Pa.

[0051] In some specific embodiments, the vacuum forming apparatus 2 further includes a water circulation assembly comprising a return pipe 203, a water supply device 204, and a water inlet pipe 205, all in sequential, circular communication with the vacuum water tank 201. The water inlet pipe 205 is provided with a water flow regulating valve. The water supply device 204 includes a connected circulating water tank and a water pump. When the water pump is running, water from the water inlet pipe 205 enters the vacuum water tank 201, passes through the return pipe 203, and then returns to the circulating water tank. The water level in the vacuum water tank 201 can be adjusted by adjusting the water flow regulating valve on the water inlet pipe 205.

[0052] In some specific embodiments, the vacuum forming device 2 also includes a slow flow tube 206 connected to the water supply device 204, and the end of the tube wall of the slow flow tube 206 fits against the outer wall of the straw forming mold so that the water flows down along the straw forming mold 202; the water outlet of the slow flow tube 206 points to the edge of the material inlet of the straw forming mold 202. On the one hand, the outflowing water flow can preliminarily cool the straw so that the straw has a certain stiffness and does not deform. On the other hand, the water flow out of the slow flow tube 206 also produces a liquid sealing effect on the gap between the material and the material inlet of the straw forming mold 202, thereby playing a liquid sealing role on the vacuum water tank 201, preventing the vacuum water tank from losing pressure and improving the stability of the forming process.

[0053] In some specific embodiments, the slow-flow pipe 206 is connected to the circulating water tank via a connecting pipe, and a valve is provided on the connecting pipe to control the outflow of water from the slow-flow pipe 206 .

[0054] In some specific embodiments, the end of the slow-flow pipe 206 is in a shovel-shaped structure, and the cross-section of the water outlet gradually increases along the direction of the water flow.

[0055] In some specific embodiments, the water outlet of the slow flow tube 206 is located 0.4 to 0.8 cm above the material inlet of the straw forming mold 202, so that the water flow can completely cover the gap between the material and the material inlet of the straw forming mold 202. At the same time, the water flow has almost no impact force on the material, thereby avoiding deformation of the straw.

[0056] Preferably, the slow-flow tube 206 is a stainless steel square tube, and the end of the stainless steel square tube is a shovel-shaped structure. The slow-flow tube is a stainless steel square tube, which facilitates processing of the end thereof to form a shovel-shaped structure.

[0057] In some specific embodiments, the vacuum forming apparatus 2 further includes a negative pressure assembly, which includes a vacuum pump 207, a vacuum pipe 208 connecting the vacuum pump 207 and the vacuum water tank 201, and a liquid seal box connected to the vacuum pump. In actual use, the height of the vacuum pipe 208 extending within the vacuum water tank 201 must be maintained above the liquid level in the vacuum water tank 201.

[0058] In some specific embodiments, the negative pressure assembly further includes a liquid-sealed box 209 connected to the vacuum pump 207. Preferably, a first pressure gauge is located above the vacuum water tank 201, a second pressure gauge is located on the vacuum pipe 208, and a third pressure gauge is located above the liquid-sealed box 209. These three pressure gauges allow real-time monitoring of the pressure within the vacuum water tank 201 and the operation of the negative pressure assembly, ensuring a stable negative pressure within the vacuum water tank 201. It is understood that under normal circumstances, the value on the first pressure gauge equals the value on the second pressure gauge, and the third pressure gauge displays 0. However, when the values on the first and second pressure gauges are unequal, and / or the third pressure gauge indicates positive or negative pressure, an abnormality is present. For example, when the water level within the vacuum water tank 201 is too high and overflows to the location where the first pressure gauge is installed, the values on the first and second pressure gauges will be unequal; when the motor of the vacuum pump 207 rotates in reverse, the third pressure gauge will display negative pressure; and when air enters the vacuum pump 207, the third pressure gauge will display positive pressure.

[0059] In some specific embodiments, the crystallization device 3 is a hot water heating crystallization device, which has heating and temperature control functions to achieve temperature control effects at different temperatures. Specifically, the crystallization device 3 includes a hot water crystallization tank 301, a heating water tank 302, and a circulation pump 303, which are interconnected in a circular manner. The hot water crystallization tank 301 is used to store hot water for crystallization, forming a hot water constant temperature crystallization area. During the passage of the tubular structure, the hot water stored in the hot water crystallization tank 301 is used to crystallize the continuously output tubular structure. The hot water crystallization tank 301 is also provided with a material inlet and a material outlet for the tubular structure to pass through.

[0060] In some specific embodiments, a circulation pipe is provided between the crystallization hot water tank 301 and the heating water tank 302, and the crystallization hot water tank 301, the heating water tank 302, and the circulation pump 303 are sequentially connected in a circulation manner through the circulation pipe. A water heater is provided in the heating water tank 302.

[0061] In some specific embodiments, the circulation pump 303 can be arranged in the heating water tank 302 or the crystallization hot water tank 301 and connected to the circulation pipe; and / or, the crystallization hot water tank 301 and the heating water tank 302 can be integrated into a constant temperature water tank with a built-in heater.

[0062] In some specific embodiments, the crystallization hot water tank 301 and the heating water tank 302 are also provided with thermometers and liquid level gauges to ensure that a constant temperature crystallization area with sufficient hot water of suitable temperature is maintained in the crystallization hot water tank 301, thereby achieving the expected crystallization effect.

[0063] In some specific embodiments, the heating water tank 302 is also connected to a water inlet device. Since the hot water in the crystallization hot water tank 301 will flow out from the material inlet and outlet, in order to keep the water level in the crystallization hot water tank constant, it is necessary to replenish water in the heating water tank 302 in time.

[0064] Preferably, the crystallization hot water tank 301 and the heating water tank 302 are made of food-grade stainless steel, and the outer layers of the crystallization hot water tank 301 and the heating water tank 302 are both equipped with insulation devices to save energy.

[0065] An embodiment of the present invention further provides a straw production method, which is produced using the straw production system described above, comprising:

[0066] S1, at the start of operation, the blowing device assists the material in being formed into a tubular structure.

[0067] Specifically, at the start of operation, the water level of the vacuum water tank 201 is below the material channel. The valve unit is controlled to connect the in-mold channel 401 with the blowing device 402, and the blowing device 402 is controlled to blow air into the in-mold channel 401. The water pump is turned on to pull the material extruded from the straw extrusion die 1 into the straw forming die 202. The material is then formed into a tubular structure by the blowing of the blowing device 402.

[0068] S2, in the operation transition stage, controlling the water level of the vacuum water tank to gradually rise until the tubular structure is submerged in water, and then evacuating the vacuum water tank.

[0069] Specifically, the water level of the vacuum water tank 201 can be gradually increased by adjusting the water flow regulating valve, and when the water level in the vacuum water tank 201 overflows the tubular structure, the vacuum water tank 201 is vacuumed; after the water level in the vacuum water tank 201 reaches the set water level, the blowing device 402 is turned off;

[0070] S4, during a stable operation phase, air is pumped into the tubular structure through the air pumping device.

[0071] During the stable operation stage, after the vacuum degree in the vacuum water tank 201 is stable, the valve unit is controlled to connect the in-mold channel 401 with the exhaust device 403 , and the exhaust device 403 is controlled to exhaust air into the in-mold channel 401 .

[0072] Actual production has proven that straws made from PGA using conventional air-blowing and cold-water cooling methods have an odor level of 4.5-5, while straws produced using the straw production system of the present invention have an odor level of 2-3, meeting the standard odor level of ≤ 4 for typical straws. (Odor levels are: Level 2, odor present but non-disruptive; Level 3, noticeable odor but non-disruptive; Level 4, disruptive odor; Level 4.5, between Levels 4 and 5; Level 5, strong disruptive odor).

[0073] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. A straw production system, characterized in that: The invention comprises an extrusion device, a vacuum forming device (2) and a crystallization device (3) connected in sequence, wherein the extrusion device is provided with a straw extrusion die (1). The vacuum forming device (2) comprises a vacuum water tank (201), a negative pressure component, a water circulation component, and a straw forming mold (202) arranged on the vacuum water tank (201); the negative pressure component comprises a vacuum pump (207), a vacuum pipe (208) connecting the vacuum pump (207) and the vacuum water tank (201), and a liquid seal box (209) connected to the vacuum pump (207); the height of the vacuum pipe (208) extending in the vacuum water tank (201) is located above the liquid level of the water body in the vacuum water tank (201); the water circulation component comprises a return pipe (203) which is cyclically connected to the vacuum water tank (201), a water supply device (204) and a water inlet pipe (205); the water supply device (204) comprises a circulating water tank and a water pump which are connected to each other; after the water pump is running, water in the water inlet pipe (205) enters the vacuum water tank (201) and then returns to the circulating water tank through the return pipe (203); The straw production system further comprises an air blowing device (4), the air blowing device (4) comprising a valve unit, an in-mold channel (401), and an air blowing device (402) and an air suction device (403) respectively connected to the in-mold channel (401), the in-mold channel (401) being arranged in the straw extrusion die (1), and the valve unit being used to connect the in-mold channel (401) with the air blowing device (402), or to connect the in-mold channel (401) with the air suction device (403); During the production process, the material is formed into a tubular structure after passing through the straw extrusion die (1) and the straw forming die (202), and the in-mold channel (401) is connected to the tubular structure.

2. A straw production system according to claim 1, characterized in that: The valve unit includes a three-way valve, and the blowing and exhausting device (4) also includes a blowing pipe (404) and an exhaust pipe (405). The in-mold channel (401), the blowing pipe (404) and the exhaust pipe (405) are all connected to the three-way valve; the blowing device (402) is connected to the blowing pipe (404), and the exhaust device (403) is connected to the exhaust pipe (405).

3. A straw production system according to claim 2, characterized in that: The blowing pipe (404) is provided with a first gas flow meter and a first gas volume control valve, and the exhaust pipe (405) is provided with a second gas flow meter and a second gas volume control valve.

4. A straw production system according to claim 1, characterized in that: The vacuum forming device (2) further comprises a water circulation assembly, wherein the water circulation assembly comprises a return pipe (203), a water supply device (204) and a water inlet pipe (205) which are sequentially connected in a circular manner to the vacuum water tank (201), and a water flow regulating valve is provided on the water inlet pipe (205).

5. A straw production system according to claim 4, characterized in that: The vacuum forming device (2) further comprises a slow flow tube (206) connected to the water supply device (204), the end of the tube wall of the slow flow tube (206) is in contact with the outer wall of the straw forming mold (202), and the water outlet of the slow flow tube (206) points to the material inlet edge of the straw forming mold (202).

6. A straw production system according to claim 5, characterized in that: The end of the slow-flow pipe (206) is in a shovel-shaped structure, and the cross section of its water outlet gradually increases along the direction of the water flow.

7. A straw production system according to claim 6, characterized in that: The water outlet of the slow-flow pipe (206) is located 0.4 to 0.8 cm above the material inlet of the straw forming mold (202).

8. The straw production system according to claim 1, characterized in that: A first pressure gauge is provided above the vacuum water tank (201), a second pressure gauge is provided on the vacuum pipe (208), and a third pressure gauge is provided above the liquid seal box (209).

9. A straw production system according to any one of claims 1 to 8, characterized in that: The crystallization device (3) comprises a crystallization hot water tank (301), a heating water tank (302), and a circulation pump that are circulated and connected; The crystallization hot water tank (301) is provided with a material inlet and a material outlet.

10. A straw production method, characterized in that: Production is carried out using the straw production system according to any one of claims 1 to 9, comprising: At the start of operation, the blowing device (402) assists the material in being formed into a tubular structure; During the operation transition phase, the water level of the vacuum water tank (201) is controlled to gradually rise until the tubular structure is submerged in water, and then the vacuum water tank (201) is evacuated; During the stable operation phase, air is extracted into the tubular structure through the air extraction device (403).

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