Hướng dẫn đầy đủ về máy hàn túi

Packaging plays a crucial role in ensuring the safety, quality, and shelf-life of products, especially in the food and pharmaceutical industries. Various types of packaging bags, such as pillow-shaped bags, flat bags, and self-supporting bags, are widely used, each offering distinct advantages in terms of sealing quality, aesthetics, and suitability for specific product types. Among the many methods, vacuum packaging stands out due to its ability to extend product shelf life by slowing oxidation, inhibiting microbial growth, and making storage more efficient. Vacuum packaging machines, particularly single-chamber and double-chamber types, are essential in automating the vacuuming, sealing, and inflation processes, ensuring product integrity and improving overall packaging efficiency.

Packaging bag types

Common plastic film bags are in the following forms:

Pillow-shaped bag. The general seam method is to overlap the longitudinal seam and then seal the two ends, as shown in Figure (1).

Flat bag. It can be divided into three-sided sealed bag Figure (2) and four-sided sealed bag Figure (3).

Stand up bag. Common ones are pointed corner bag Figure (4), triangular bag Figure (5), and cubic column bag Figure (6).

In the bag making process, it is generally sealed longitudinally first and then horizontally. Therefore, within the entire length of the overlapped and butt-jointed sealing seams of the pillow-shaped bag, three or four layers of film overlap at the sealing part, which has a certain impact on the sealing quality. The number of layers of film within the entire length of the sealing seam of the flat three-sided sealed bag is equal, and the sealing quality is better, but the bag shape is asymmetrical and the aesthetics is slightly worse. Four-sided sealing overcomes the shortcomings of the above two situations, but more packaging materials are used, and it is often used for simple sealing machines for small packages. Various self-supporting bags have beautiful appearance and the advantage of being self-supporting, which is convenient for subsequent packaging process and product placement and display. However, they have high requirements for packaging materials and composite packaging materials should be used.

Vacuum packaging machine

Vacuum packaging is to put food into the packaging container, remove the air in the container, reach a certain vacuum degree, and then seal and package it. This is a new packaging method that has developed rapidly in the food and pharmaceutical industries at home and abroad in recent years. It has the following characteristics:
(1) Slow down oxidation and deterioration, inhibit microbial reproduction, and thus extend the shelf life of food. Foods are attached to a certain number of microorganisms, which reproduce in the air and cause food to spoil. After the air is removed, microorganisms inhibit reproduction in the absence of oxygen, and many easily oxidized substances also oxidize slowly due to lack of oxygen.
(2) It is conducive to thermal sterilization operation. If there is a large amount of air in the container containing food, the heat conduction is poor, the food takes a long time to heat up, and the sterilization time is extended; after the air is removed, the food quickly rises to the required temperature. In addition, removing air can also prevent the container from rupturing due to gas expansion during the heating and sterilization process.
(3) After the air is removed, the volume is reduced, which is convenient for storage and transportation.
(4) Since the packaged food needs to maintain a certain amount of moisture and the packaging material also has a certain degree of air permeability, the vacuum packaging cannot achieve complete vacuum, and the highest vacuum degree can reach -0.096~0.099MPa.

Structural principle of single-chamber vacuum packaging machine

The figure shows the structure and working principle of a medium-sized vacuum packaging machine, which is widely used in small and medium-sized food processing plants.

The packaging process of bagged food is: place the package body in the vacuum tank for orientation, place the bag mouth on the heating block, put the vacuum suction nozzle into the bag mouth, and press down the vacuum tank cover. After that, the limit switch and relay will automatically control the vacuuming, hot pressing and sealing, power off cooling, automatic opening and other processes. The vacuuming degree, time, heat sealing time, cooling time, etc. should be tested and adjusted in advance.
The working process of the small vacuum packaging machine is the same as that of the small vacuum packaging machine, except that each process is manually controlled.
The heating method for hot-pressing sealing usually adopts pulse heating. Its heating element adopts low-resistance wire and the voltage is about 10-50V. When a strong current is passed, the wire heating element immediately generates heat and transmits it to the heating block, and then the bag mouth is hot-pressed and sealed. The sealing cooling method can be natural cooling or cooling water circulation to make the bag mouth cool quickly to prevent the plastic film in the sealing area from being overheated.

Structure of double-chamber vacuum inflation packaging machine

Working room. It consists of an upper cover and a lower base (chamber A and chamber B). The upper cover and the lower base are sealed with a rubber ring.
There are two small air chambers on the top of the cover. The small air chambers are equipped with a heating mechanism. A vacuum gauge is installed outside the cover top, and there are also electric heating terminals, small air chamber pipes, and air chamber exhaust pipes. The upper and lower covers are connected by a set of four-bar linkages to ensure smooth rotation.
Heating and sealing mechanism. The heating head and the cover are connected by two copper sheets at both ends. The two fastening copper blocks at both ends of the electric heating belt are fastened with screws to prevent poor contact. The electric heating head and the sealing cap are absolutely insulated to prevent short circuit.
During operation, the small air chamber and the large air chamber are evacuated at the same time. The heating head does not work when the pressure difference at both ends is the same. When the air valve of the small air chamber is connected to the atmosphere to generate a pressure difference, the heating head is pressed down, the seal is pressed and heated at the same time. The heating time and temperature can be adjusted. The heating system is a pressure regulating type, which can be used for different packaging materials. The selection knob is set on the machine control panel. The electric heating belt is an alloy belt. No-load heating is strictly prohibited.
Base. It is divided into two chambers, A and B, with 16 inflation nozzles on both sides. There are heating pads at the corresponding position of the heating head, and a cam switch group for switching between chambers A and B is set underneath.

Phần kết luận

Packaging bag types and vacuum packaging machines are integral to the food and pharmaceutical industries, ensuring product quality and prolonging shelf life. While various bag types are available to suit different materials and aesthetics, vacuum packaging machines enhance the preservation process by removing air, preventing oxidation, and facilitating thermal sterilization. The structure and working principles of both single-chamber and double-chamber vacuum packaging machines play a significant role in streamlining the packaging process, making it more efficient, reliable, and suitable for a variety of products. Understanding these packaging methods is essential for optimizing packaging operations and ensuring that products are well-protected for storage and transportation.

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