Patent Application
20060035777
This invention relates generally to valve bags, and more particularly to valve sleeves used in valve bags for granular products, such as animal feed, animal supplements, grains, and fertilizers.
Flexible bags such as paper shipping sacks may include sealable sleeves placed in the filling valves. A sealable sleeve provides a convenient means to securely close the flexible bag to prevent the contents of the bag from leaking or sifting out of the bag. Sleeves may be constructed of polyethylene tubing or of paper, for example.
A typical paper sleeve for a paper shipping sack (such as a pasted valve type multi-wall shipping sack) is made from a rectangular sheet of kraft paper that is rolled into a cylindrical shape and secured in the cylindrical shape by overlapping and gluing opposing edges of the sheet of paper to one another, forming a lapped seam. Such a sleeve is typically mounted to an opening, called a valve or filling aperture, located in a corner of the bag, that is used to allow introduction of the product that is to be held within the bag. This arrangement has been used even in more advanced shipping sacks that include a thermoplastic film liner adhered to the inner surface of the sleeve valve. In order to seal the paper sleeve and therefore the valve or filling aperture after the shipping sack is full, heat is applied to the thermoplastic film liner near an exterior end of the sleeve valve to secure the contents within the shipping sack. Sealing is typically accomplished using conduction heating, pressure, microwave energy, or ultrasonic application.
The trend in manufacturing processes now, however, particularly with extended valve tube bags, is not to provide one sealing apparatus per packing apparatus, since it requires less capital expense to use only one or two sealing apparatus for a packaging line, and the line speed can also be increased if common sealing apparatus are used for all the packing apparatus. The difficulty lies in that the filled, but unclosed and unsealed bags must be transported by conveyer to the sealing apparatus location. The bags may typically be dropped onto a conveyer.
Due to the stiffness of the valve tube material, the valve tube tends to remain open somewhat, as the bag is dropped onto the conveyer, leading to unacceptable spillage and dusting. In addition, the operation of the sealing apparatus may require that the bag be tipped from an upright position, to a position on its side, further leading to the possibility of dusting and spillage.
The foregoing illustrates limitations known to exist in present valve bags. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth-above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.
In one aspect of the present invention, this is accomplished by providing a valve bag comprising: a bag body; a valve passage formed in the bag body; and a sealable valve sleeve secured within the valve passage, an exterior portion of the valve sleeve extending along an adjacent portion of the bag body, the exterior portion of the valve sleeve being unsecured to the adjacent portion of the bag body.
The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing figures.
As shown in
Valve (or valve sleeve) 16 is positioned within the valve passage 18 and is secured (as described below) to the inner and outer flaps 20, 22. Valve 16 consists of a tubular valve liner 24, which is preferably formed from a polymeric material such as polyethylene, with an upper valve support 26 and a lower valve support 28 secured to the valve liner 24. Typically, valve supports 26, 28 are formed from kraft paper and are separate flat pieces of the kraft paper.
An exterior portion 30 of the valve sleeve 16 extends laterally beyond the end of outer flap 22. The exterior portion 30 of valve sleeve 16 is not secured to inner flap 20 (shown at 50). This allows the unsecured exterior portion 30 to be rotated upward after bag 10 is filled so that both sides of this exterior portion 30 are accessible by a sealing device. Depending upon the material used for the valve liner 24, pressure and/or heat is applied to the exterior portion 30 to seal the valve 16 closed. Other means, not shown, can be used to seal the valve closed, such as adhesives, deformable closure systems, similar to those commercially available under the trademark Ziploc®, etc.
Preferably, the inner end 32 of the upper valve support 26 extends interiorly beyond the valve liner inner end 38. Also, preferably, the inner end 34 of the lower valve support extends to the valve liner inner end 38. The interior portion of the valve sleeve 16 is secured to and only partially supported by the inner flap 20. At least a portion (the right most portion shown in
In one embodiment, the valve sleeve 16 has a first or exterior end 30 that remains unsecured to the adjacent portion of the inner flap 20, a middle portion 36 that is secured to the inner flap 20, and a second end portion (the right most portion shown in
During filling, material flows into bag 10 through valve passage 18 in valve sleeve 16. As the material approaches the top 12 of bag 10, the material will fill the area between the inner end 42 of the inner flap and the lower valve support 28 causing the valve sleeve 16 to collapse and close the valve passage 18. This allows temporary handling of the filled bag until the exterior portion 30 of valve 16 can be permanently sealed closed.
