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AssigneeThe Dow Chemical Company
InventorsEddie Lee Greenawalt, Lorenzo Dow Geren
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Side gusseted industrial bags are continuously (or intermittently) formed from continuous web materials, and simultaneously filled and sealed in one fast operation by the method and apparatus of this invention. The various features of the invention include a tube former which wraps the web about a shaped filling mandrel most preferably with the assistance of an air bearing, registration and tension controls to accurately maintain the register of the web in relationship to printed blocks or indicia; evacuation steps to neatly gusset the bag with or without mechanical assistance, to tighten the bag firmly about the product, and to continuously wash the inside welding surfaces thereof with a cleansing high velocity air stream to thereby retain such surfaces in a more virgin or noncontaminated welding condition; filling steps that are practiced to provide a free margin of material at the top of the bag to complement the welding and gusseting steps; and hot gas welding and chilling techniques that can provide tough welds or seals with high repeatability, and which are able to withstand the shock or weight of the product load with sufficient immediacy to enable fast production cycles.
In the method generally wherein web material is continuously drawn off a supply roll and converted into a continuously moving tube, simultaneously with the periodic entry of the product into the tube, and the collapsing and transverse sealing of the tube at regular intervals to form therefrom filled bags, the steps to register regularly occurring printed matter on the material with respect to the position of the transverse seals comprising:
In apparatus wherein web material is continuously drawn off a supply roll and converted by a tube forming means into a generally vertical, continuously moving tube, simultaneously with the periodic entry of product into the tube, and the collapsing and transverse sealing of the tube at regular intervals to form therefrom filled bags, the improvement which comprises, means to register regularly occurring printed matter on the material with respect to the position of the transverse seals:
Dependencies are inferred from the claim text.