Apparatus and method of packaging large items

摘要

This invention discloses a packaging apparatus and method for large size products such as subprimals of meat. The products to be packaged are characterized as often having irregular surfaces and voids which make sealing of the film without wrinkles very difficult, particularly after bringing to a condition of reduced pressure. There is shown apparatus for forming a drape of film from two rolls of film and into this drape of film is advanced the product to be packaged. This drape is formed into a tubular film around the product and with this tube open at both ends. Into these open ends of the tube are moved spreader probes or bars which operate as pairs and are moved away from one another by a pneumatic cylinder which is actuated by appropriate apparatus so that the spreader probes as they move apart cause the film in these ends to be brought to a narrow opening and under a slight stretch. This elongated opening is substantially equally spaced from a theoretical center line of the tubular film. With the probes moved to a condition for stretching the film, the encased product and film are brought in way of a film heater and then are moved to a vacuum chamber whereat the spreader probes are withdrawn from the ends of the package. While and when in this chamber the interior and product are brought to a condition of reduced pressure. While still in the chamber and under the influence of reduced pressure, the elongated ends of the tubular film are heated and sealed so that these ends of film are substantially free of wrinkles. After sealing and with the ends still clamped, the chamber is opened to the atmosphere to allow the film ends to tightly enclose the product. The package is then removed from the vacuum chamber. Large products when packaged by skin packaging apparatus tend to have the film overstretched. This occurs when the product is used to shape and mold a heated film. With the product pushed into the draped film and a tube formed by closing and sealing the rear of the drape, overstretching of the film is eliminated or minimized to tolerable levels so that the resulting package is absent weak portions of film.