Patent Publication Number: US-2005132669-A1

Title: Vacuum packaging method and mechanism

Description:
FIELD OF THE INVENTION  
      The present invention relates to a vacuum packaging method and mechanism adopted for use for a sealing body which contains a core material and particularly to a direct vacuuming method that is coupled with a special vacuumed apparatus to seal the sealing body that contains the core material in a vacuum condition.  
     BACKGROUND OF THE INVENTION  
      The vacuum packaging technique was first developed in 1940s. Since 1950, with successful developments of polyurethane and polystyrene films, vacuum packaging techniques for merchandise packaging have been developed rapidly. Vacuum package generally is to place goods in an airtight container, and evacuates the air inside the container before sealing the opening of the container. Its main purpose is to prevent oxygen and moisture from entering the container to avoid microbes from breeding in the container or the goods from oxidizing and deteriorating. It also can prevent the container from being expanded or cracked. This happened in the past when package was sealed thermally. Vacuum packaging can be used for a wide variety of goods, such as processed meat and grains, and electronic products that might be degraded by oxidation. The vacuum packaged goods generally have a shelf life as much as three times of the goods not being vacuum-packaged. When the core material are open-cell polystyrene foams, open-cell polyurethane foams, carbon/silica aerogel or the like, the thermal insulation effect of the vacuum insulation panel is three to seven times the conventional blowing PU. Moreover, the vacuum condition of the sealing body can be maintained without degrading when air and moisture permeability is low. Therefore it can be used for a long period of time in refrigerators or other apparatus that need to preserve temperature.  
      Although the conventional direct vacuuming techniques do not have dimensional limitation for the sealing body, and are applicable for packaging versatile of goods in small quantities, during vacuuming the pressure difference between the interior and exterior tends to create creases on the sealing body that contains core material. This not only makes packaging quality difficult to control, using fixtures to anchor the sealing body also tends to damage the structure of the gas deterrent film during thermal sealing operation. To remedy the foregoing problems, U.S. Pat. No. 6,106,449 discloses a vacuum insulated panel and container that coats a leak-proof oil on an evacuation tube and inserts the evacuation tube into an evacuation hole of the sealing body until reaching the core material contained in the sealing body. This prevents creases caused by the pressure difference during the vacuuming operation and block outside air from entering the sealing body. While it can improve the vacuum quality, its production process is complex. The production process takes much more time. The quality is difficult to control. It creates a lot of inconveniences to operators.  
     SUMMARY OF THE INVENTION  
      Therefore the invention aims to resolve the problems mentioned above by providing a vacuum packaging method and mechanism that does not require coated leak-proof oil and does not have dimensional limitations. Further, it should be applicable to products in varying quantities, and also should provide a simplified production process to make quality control easier. The invention can be added modularly according to preference.  
      The vacuum packaging method and mechanism according to the invention includes a vacuuming apparatus that has a front end and a periphery for drawing air respectively, an airtight compression module and a thermal press sealing apparatus. The method includes, first, encasing a core material in a sealing body by thermal sealing that has a reserved opening. Second, inserting the vacuuming apparatus into the reserved opening until in contact with the core material in the sealing body. Third, using the vacuuming apparatus to draw air through the periphery thereof so that the sealing body around the reserved opening is adsorbed smoothly to the vacuuming apparatus, and partly seals the surrounding of the reserved opening. This prevents external air from seeping in. Thereby, the front end of the vacuuming apparatus can draw air to keep the sealing body in a desired vacuum condition. Finally compress and thermally seal the reserved opening to seal the sealing body in the desired vacuum condition and encase the core material in the sealing body.  
      The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a process flow chart of the invention  
       FIG. 2  is a perspective view of the vacuum packaging mechanism of the invention.  
       FIG. 3  is a schematic view of the vacuuming apparatus of the invention with a sealing body adsorbing thereon.  
       FIG. 4  is a schematic view of the sealing body with a reserved opening and the surrounding of the adsorption area.  
       FIG. 5  is a schematic side view of the vacuum packaging mechanism.  
       FIG. 6  is a schematic view of the vacuuming apparatus in a vacuuming condition. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Referring to  FIG. 5 , the vacuum packaging mechanism according to the invention includes a pair of corresponding thermal press sealing apparatus  40 , a pair of corresponding airtight compression modules  20  and a vacuuming apparatus (not being marked in  FIG. 5 ) encased by a sealing body  30 . As shown in  FIG. 5 , the vacuuming apparatus  10  is encased in the sealing body  30  that is clamped between the airtight compression modules  20 , and the airtight compression modules  20  are located between the thermal press sealing apparatus  40 . Also referring to  FIG. 2 , the airtight compression module  20  includes a U-shaped upper plate  21  and a U-shaped lower plate  26  that have respectively a rubber sealing pad  22  and  27 . The upper plate  21  and lower plate  26  may be turned about one side of the plate to clamp the vacuuming apparatus  10  in the center portion thereof. The vacuuming apparatus  10  has a cross section flattened like an eye with two convex sides that is thicker in the middle and has a porous section  12 . In this embodiment, the porous section  12  is a sintered powder metallurgy substance through which the vacuuming apparatus  10  can draw the air while the rest portion is air impermeable. The vacuuming apparatus  10  has a front end forming a flattened reciprocal air suction module  13  which may be located in a rectangular opening  14  of the vacuuming apparatus  10  in an extendable manner.  
      Referring to  FIG. 6 , the sealing body  30  contains a core material  33  and is thermally sealed around the core material except a reserved opening  31  (step  101 ), which is slightly larger than the vacuuming apparatus  10 , to allow the vacuuming apparatus  10  to be moved in and out of the sealing body  30 . The front end of the air suction module  13  can run through the reserved opening  31  of the sealing body  30  and be extended inwards until reaching the core material  33  housed in the sealing body  30  (step  102 ). Then the vacuuming apparatus  10  can be activated to draw air around the porous section  12  of the vacuuming apparatus  10  so that the sealing body  30  is outside the heat seal section  32 . However, abutting the reserved opening  31  will be adsorbed onto the vacuuming apparatus  10  to bond the sealing body  30  to the vacuuming apparatus  10  and prevent producing creases (step  103 ). Then the upper and lower U-shaped plates  21  and  26  of the air tight compression module  20  are moved along the periphery of the vacuuming apparatus  10  and clamp the vacuuming apparatus  10 . The sealing body  30  is adsorbed on the vacuuming apparatus  10  in the center (as shown in  FIG. 4 ), so that the surrounding of the reserved opening  31  of the sealing body  30  forms a local sealing (step  104 ). Thereby, the interiors of the sealing body and the core material are isolated from the exterior, and external air cannot enter the sealing body. Thereafter, air can be drawn through the front end of the reciprocal air suction module  13  until the vacuum condition of the sealing body  30  reaches a desired degree (step  105 ). Then the reciprocal air suction module  13  will retract automatically into the vacuuming apparatus  10 . In order to maintain the sealing body  30  in a desired vacuum condition after being vacuumed, the thermal press packaging apparatus  40  can be used to compress the airtight compression module  20 , to make sure that no air has passed through the reserved opening  31  to the sealing body  30 . Then the reserved opening  31  is thermally sealed. Thus air is completely blocked from entering the sealing body  30  (step  106 ). Referring to  FIG. 5 , after the thermal press packaging apparatus  40  completes the thermal sealing, the pressure to the airtight compression module  20  will be released automatically, and air drawing at the porous section  12  of the vacuuming apparatus  10  will be stopped. Then the packaged sealing body  30  can be removed easily.