Dust-free sealer for valve bags

The invention provides for a sealing device for a valve bag. The sealing device has two sections separated by a perforated seam. Each section is secured to one side of the valve channel and has an adhesive surface covered by a protective sheet. The two sections are perforated by the filling tube when the valve bag is filled, once the valve bag is filled the protective sheet is cleaned and removed and the two sections of the sealing device are pressed together and secured by the interaction of their adhesive surfaces.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to valve bags and, more specifically to a mechanism for sealing a valve bag used to contain and transport fine granular products (e.g., rice hull ash) to prevent loss of the products from the valve bag during the handling and shipping of filled valve bags.

2. Description of the Related Art

Plastic valve bags are multi-walled sacks made of a flexible plastic material. Typically, valve bags are formed by cutting and overlapping each layer of plastic along its length. The overlapping region on the long side of the bag is heat sealed, as well as the short sides or ends; provided that a portion of the long side is left unsealed close to one end of the bag to provide a fill hole or valve channel. Alternatively, the valve channel may be configured along the short side of the bag.

Valve bags are filled through a filling tube inserted into the valve channel. Once the valve bag is filled, the bag is upended so that the weight of the filling material closes the valve channel. However, some of the filling material escapes through the unsealed valve channel whenever the valve sack is being handled. For example, the filling material will seep out of the unsealed valve channel during transport so that the filling material is deposited between the layers of bags in a container. When the consumer seeks to remove the filled valve bags from the shipping container, the loose filling material gets into workers' eyes generating a source of eye irritation. To prevent worker health problems and lost time due to eye irritation, a number of attempts have been made to find a suitable sealing mechanism for valve bags to prevent the sieving or leakage of the bag contents back through the valve channel after filling. Typically, these mechanisms have included coating the inner surfaces of the overlapping valve channel with an adhesive or other sealing material, which may be activated by heat or ultrasonic means. Recently, attempts have been made to construct a valve bag sleeve such as described in U.S. Pat. No. 6,164,823 or a self-closing bag such as described in U.S. Pat. No. 6,126,316 to address this problem.

Although some of the sieving problems have been prevented by these various sealing methods, the current sealing mechanisms are not effective in a number of situations or are inapplicable to many mechanical bag-filling systems. Sieving problems are accentuated in the case of filling materials such as rice hull ash.

Harvested paddy rice is subjected to processing operations that remove the rice hulls from the paddy rice. A major use of the separated rice hulls is as a fuel source. Burning rice hulls releases a great deal of energy and renders fine amorphous SiO2or black dust particles called rice hull ash. These dust particles are primarily composed of silica and contain considerable air space within its interstices, thereby producing a remarkably insulative material often used to insulate molten steel.

Typically, rice hull ash is packaged, sold and transported in plastic valve bags. To date there has been no successful mechanism for sealing valve bags containing rice hull ash during their transport. One problem is that once a bag is filled on the fill tube and is removed, the fill tube drags particles of the rice hull ash along with it across the ends of the valve channel contaminating the opposing surfaces, thereby preventing a tight seal when the adhesive on the opposing surfaces is activated. This is a particular problem if the adhesive is to be activated by heat, since the rice hull ash has particularly strong insulative properties.

Thus, there is an existing need to securely seal a valve bag filled with minute particles having insulative properties. Since filling of the valve bag typically contaminates the sides of the valve channel with the particles with which the valve bag is filled, a protection means is needed that will protect the surfaces of the valve channel during the filling of the bag to ensure the secure sealing of the valve channel once the valve bag has been filled and flattened.

SUMMARY OF THE INVENTION

One aspect of the invention provides for a sealing device comprising a sheet of flexible material having a first section and a second section at opposed ends of the sheet, wherein the sheet is sufficiently flexible such that the first section is foldable over the second section; a first adhesive underlying at least one section of the sheet; a second adhesive on an upper surface of at least one section of the sheet; and a removable upper protective sheet covering the second adhesive.

Another aspect of the invention provides for a sealing device comprising two inside sections having a first adhesive coating an inner surface of the inside sections; two outside sections having a second adhesive coating an outer surface of said outer sections; and a removable protective sheet covering the adhesive coating of said outer surface of said outer sections.

Yet another aspect of the invention provides for a valve bag having a tubular body and a valve channel, wherein the improvement includes a sealing device comprising: a sheet of flexible material having a first section and a second section at opposed ends of the sheet, wherein the sheet is sufficiently flexible such that the first section is foldable over the second section; a first adhesive underlying the sheet, such adhesive securing the backside of the first section to an underside of a top side of the valve channel and the backside of the second section to the upper side of the bottom side of the valve channel; a perforated seam located between the first section and the second section of the sheet and substantially centered in the valve channel; a second adhesive overlaying an upper surface of the first and second sections of the sheet; and a removable upper protective sheet covering the second adhesive; whereby when the protective sheet is removed from the second adhesive on the upper surface of the first and second sections, the top side of the first section is folded over the top side of the second section of the sheet and the first and second sections are pressed together such that the valve channel is sealed by the interaction between the second adhesive on the upper surface of the first section with the second adhesive on second section.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to the manufacture, installation and use of a sealing device for sealing a valve channel of a valve bag; particularly a valve bag filled with minute particles having insulative properties that negate the heat sealing of the valve channel.

Referring now to the drawings, and initially toFIG. 1, it is emphasized that the Figures, or drawings, are not intended to be to scale. For example, purely for the sake of greater clarity in the drawings, layer thicknesses and spacings are not dimensioned as they actually exist in the assembled embodiments.

A typical valve bag10has a tubular configuration with long sides11and12and short sides13and14as shown in FIG.1. Valve bags are preferably multi-walled, for example having 2 to 4 layers. For simplicity, however, the valve bag10is depicted in the Figures as being made from only a single layer of plastic. The valve bag10is generally formed by cutting and overlapping a layer of plastic along its length. The overlapping region on the long side of the bag is heat sealed, as well as the short sides13and14; provided that a portion of one side is left unsealed close to one end of the bag to provide a fill hole or side valve channel16.

A side valve channel16is shown in more detail in FIG.2. The valve channel16is defined between the overlapping front flap22and the bottom flap24. The valve channel16is not heat sealed whereas the rest of the seam along the length of the valve bag10has been heat sealed along heat seam26. The valve channel16allows introduction of the product (not shown) that is to be held within the valve bag10. The valve channel is disposed close to the short side13of the valve bag10, but is preferably about 2 to about 6 inches below the intersection of the heat seam26and the short side13.

An alternative configuration of a valve bag200is shown in FIG.18. The valve bag200is typically made of one or more layers of paper or plastic. Typically the short sides204and203of the ends of the valve bag200are folded towards the center of the valve bag200. Then a tubular valve channel206is secured to one of the folded short sides such that one end of the valve channel206is in communication with the interior of the valve bag200and an opposed end of the valve channel206is open to the exterior of the valve bag200. The long sides202and207of the ends are then folded over the short sides204and203and the valve channel206. Finally, a top overlay piece208is added to secure the ends of the valve bag200. Generally the interacting sections of the ends of the valve bag200are heat sealed together, except that the interior of the tubular valve channel206is left open so that a filling tube can be introduced into the exterior end of the valve channel206and introduce product into the interior of the valve bag200.

The present invention provides for a means of securely sealing a valve channel16or206of a valve bag10or200filled with minute insulative particles. The present invention prevents the contamination of the adhesive on the sides of the valve channel16or206with the particles filling the valve bag10or200by protecting at least one adhesive layer of the sealing device during the filling and flattening of the valve bag10or200.

One embodiment of the present invention provides a sealing device having two sections separated by a perforated seam. Each section is secured to one side of the valve channel and has an adhesive surface covered by a protective sheet. The two sections are perforated by the filling tube when the filling tube is inserted into the valve bag10to fill the valve bag. Once the valve bag10is filled and the fill tube removed, the protective sheet, covering the adhesive layer on each section of the sealing device, is cleaned and removed and the two sections of the sealing device are pressed together and secured by the interaction of their adhesive layers.

A preferred embodiment of the valve sealing device of the present invention is designed to fit into existing 6 inch valve channels situated along seam26of double walled 3.5-mil thick plastic valve bags. However, the sealing device may be varied in size and shape to fit into various types of valve bags. The sealing device is typically incorporated into the valve channel16as the plastic film is being formed into the valve bag10as described below, or into the valve channel206as it is being formed. Several embodiments of the sealing device of the present invention are described in the illustrative examples below.

One embodiment of the sealing device of the present invention is illustrated inFIGS. 3A and 4A. The sealing device30, illustrated inFIG. 3A, is made from a piece of soft plastic (preferably polypropylene or polyethylene) or paper approximately 7 inches high and 8 inches wide. The plastic or paper piece is folded in half widthwise and the fold is perforated to tear when pushed against by a fill tube. Then each half is folded outward back on itself to the perforated seam34. The folded sealing device30has two outside sections36aand36band two inside sections38aand38b.

FIG. 3Ais a frontal view of sealing device30as it fits into valve bag10, whereasFIG. 4Ais a backside view of the sealing device30. The back surface of the two inside sections38aand38bwill have an adhesive42applied to them as shown inFIGS. 4A and 4B. Likewise, the front surface of the two outside sections36aand36bwill have an adhesive44applied to them as shown inFIGS. 3A and 3B. To protect the adhesive before its application to the point of desired contact, removable strips of protective material39are placed over the adhesive44on the front surface of the outside sections36aand36bas illustrated in FIG.3B. Similar removable strips of protective material49are optionally placed over the adhesive42on the back surface of the two inside sections38aand38bas shown in FIG.4B. Preferably, the adhesive42is a heat activated adhesive that is activated to adhere to the sides of the valve channel16during the heat sealing of the long side of the valve bag10. If the adhesive42is heat activated, it will not need to be protected with protective material49.

When the sealing device is installed into the valve channel16, the adhesive42of the inside sections38aand38bis contacted with and adhered to the inside surface28of the front flap22and the top surface of the bottom flap24respectively. The adherence of the inside sections to the sides of the valve channel16is accomplished by a variety of means known in the art such as glue or a heat activated adhesive.

Once the inside surfaces38aand38bof the sealing device30have been adhered to the inside surface28of the front flap22and the top surface of the bottom flap24, the perforated seam34is in about the middle of the valve channel16and the front surface of the outside sections36aand36bextends beyond front flap22and bottom flap24respectively. The adhesive44on the front surface of the outside sections36aand36bis protected with removable protective strips39.

When the sealing device30is installed in the valve channel16as described above, the outside sections36aand36bwill abut each other. The adhesive44on the outside sections36aand36bis preferably protected by a single sheet of protective material52, shown inFIG. 5, having a perforated seam54in the middle the protective sheet52. When the fill tube is pushed through the perforated seam54to begin filling the valve bag10, the protective sheet52will either split into two halves or it will stay adjoined at the lower end56. The protective sheet52may be designed to remain a single piece at the lower end56by extending the protective sheet52beyond the length of the valve channel sufficiently to allow the entrance of the fill tube into the valve channel16without splitting the bottom of the protective sheet52. In addition, the lower end56is not perforated to further encourage the protective sheet52not to split at its bottom end when the fill tube is pushed into the valve channel16and through perforation34of the sealing device30to begin filling the valve bag10.

Another embodiment of the protective sheet62, shown inFIG. 6, will be cut at one end to form two strips of protective material64aand64bat its upper, while the lower end66will be a single piece. Thus, the protective sheet62will have a Y-like shape with the strips of protective material64aand64bbeing applied to the outside sections36aand36brespectively. Thus, the protective sheet62is removable in one movement by pulling upward on the bottom end66.

Once the protective sheet52or62is removed from the outside sections36aand36b, the outside sections are folded over each other and pressed together to form a consistent secure seal for the valve channel16. The width of the outside sections36aand36b, as well as the strips of protective material64aand64b, must be sufficient to ensure enough adhesive covered surface area is available to securely seal the valve channel16, even if the outside sections do not exactly align after the valve bag10is filled.

Valve bags10manufactured with the sealing device30in place are easily filled and sealed on the typical assembly line. The valve bags10are filled through a filling tube inserted into the valve channel16. Once the valve bag10is filled, the valve bag10is flattened to remove excess air, particles and dust are blown or wiped from the surface of the protective sheet52or62covering the outside sections36aand36b, the protective sheet52or62is removed, and the outside sections36aand36bare folded over on top of each other and sealed by pressing down on the adhesive layers. Once sealed, the valve channel16will not leak the filling material during handling or transport.

Overlapping Valve Channel Sealing Device

A second embodiment of the present invention is illustrated in FIG.7. The sealing device70is made from a piece of soft plastic (preferably polypropylene or polyethylene) or paper approximately 7 to 8 inches high and 4 to 5 inches wide. The plastic or paper piece is folded in half widthwise and the fold is perforated to tear when pushed against by a fill tube. The perforated seam72may or may not extend the entire length of the sealing device70, although it will extend at least the length of the valve channel16.

A cross-section of sealing device70is shown in FIG.8. The sealing device70comprises a sheet of flexible material82, a first adhesive surface layer89coating the back side of sheet82and a second adhesive surface layer84coating the top side of sheet82. The adhesive layer89on the backside of sealing device70is optionally covered with a removable protective covering87and the adhesive layer84on the frontside of sealing device70is covered with a removable protective covering86. If the adhesive layer89is a heat activated adhesive, it will not need to be protected with protective covering87. The adherence of the adhesive layer89to the sides of the valve channel16is accomplished by a variety of means known in the art such as glue or a heat or sonically activated adhesive.

FIGS. 9 and 10show sealing device70being installed in the valve bag10. The sealing device70has two sections92and94separated by a perforated seam72.FIG. 10shows the sealing device70where the bottom side of section92is applied onto the bottom side of the overlapping front flap22and the bottom side of section94is applied to the top side of bottom flap24. To protect the adhesive layer84that is on the upper surface of sections92and94before its application to the point of desired contact, removable strips of protective covering86are placed over the adhesive layer84.

The sealing device70is installed as the cut plastic film is being formed into the valve bag10. As the plastic film is folded over and heat sealed along seam26, but before the short sides13and14are heat sealed, the overlapping front flap22and the bottom flap24can be separated and laid flat to permit the easy installation of the sealing device70. As shown inFIG. 9, the sealing device70is aligned over the valve channel16and the bottom side of section92is adhered to the bottom side of the overlapping front flap22and the bottom side of section94is adhered to the top side of bottom flap24. After the sealing device70has been installed, the overlapping front flap22is folded back over the bottom flap24and the short sides13and14of the valve bag10are heat sealed, which seals the top and bottom ends of the overlapping front flap22to the bottom flap24.

When the sealing device70is installed in the valve channel16as described above, the topsides of section92and94will be aligned on top of each other. A single sheet of protective covering86having a perforated seam72in the middle the protective covering86protects the adhesive layer84on the top surface of sections92and94as shown inFIGS. 10 and 11. When the fill tube is pushed through the perforated seam72to begin filling the valve bag10, the protective covering86will either split into two halves or it will stay adjoined at the lower end76. Similarly to the protective sheet52shown inFIG. 5, the protective covering86may be designed to remain a single piece at the lower end76by extending the protective covering86beyond the length of the valve channel sufficiently to allow the entrance of the fill tube into the valve channel16without splitting the bottom of the protective covering86. In addition, the lower end76may not be perforated to further encourage the protective covering86not to split at its bottom end76when the fill tube is pushed into the valve channel16to begin filling the valve bag10.

Valve bags10manufactured with the sealing device70in place are easily filled and sealed on the typical assembly line. The valve bags10are filled through a filling tube inserted into the valve channel16. The valve bag10is then flattened to remove excess air. Once the valve bag10has been filled and flattened, the top surface of the protective covering86is cleaned by blowing a stream of air over it, by brushing dust and particles off of it, or by vacuuming it off. When the protective covering86is clean, it is removed as shown inFIG. 12from the top surface of sections92and94. The top surface of sections92and94are then folded over each other and pressed together to form a consistent secure seal for the valve channel16. The width of the sections92and94, as well as the strips of protective covering86, must be sufficient to ensure enough adhesive covered surface area is available to securely seal the valve channel16, even if the outside sections do not exactly align after the valve bag10is filled.

Fold-over Flap Valve Channel Sealing Devices

Alternative embodiments of the sealing device are shown inFIGS. 13 and 15. The sealing device100, shown inFIG. 13, is made from a piece of soft plastic (preferably polypropylene or polyethylene) or paper approximately 7 to 8 inches high and 4 to 5 inches wide. The plastic or paper piece is folded widthwise, generally one side105is made wider than the other side102, and a fold105is created. The fold105is preferably minimally perforated to assist folding of the sealing device100, but to resist tearing of the fold105during handling of the sealed valve bag10. If the fold105is perforated, it is preferably not perforated the entire length of the sealing device100.

A cross-section of the side104of the sealing device.100is shown in FIG.14. The side104comprises a sheet of flexible material106, an adhesive surface layer108on the back side of sheet106and a removable protective covering110on the bottom side of adhesive surface layer108.

FIG. 13is a pan view of sealing device100. The sealing device100has two sections, a smaller section102and a wider section104, separated by the seam105. The section102has an adhesive on its underside.FIG. 13shows the sealing device100where the adhesive layer on the bottom of section102is applied onto the valve bag10on the side of the valve channel16across from the overlapping flap103of the valve channel. The adhesive on the backside of section102may be heat activated or any other type of adhesive known in the art.

The wider section104is wide enough to pass over the overlapping flap103and be secured to the valve bag10on the opposite side of the overlapping flap103from the smaller section102. To protect the adhesive layer108that is on the under side of the wider section104before its application to the point of desired contact, a removable strip of protective covering110is placed over the adhesive layer108.

The sealing device100is installed after the valve bag10has been formed. First, the adhesive on the underside of section102is adhered to valve bag10such that it is aligned with the valve channel16and on the opposite side of the valve bag10from the overlapping flap103.

Once the sealing device100is installed on the valve bag, the valve bag10is ready for filling. The fill tube is inserted into the valve channel16to begin filling the valve bag10. Once the valve bag10has been filled and flattened, the valve bag channel16is closed and the valve bag surface around the valve bag channel is blown, wiped or vacuumed to remove any dust or particulate matter. Once the surfaces have been cleaned the protective sheet110on the bottom side of the section104is removed to expose the adhesive layer108. The adhesive layer108is pressed against the valve bag10to secure the section104to the valve bag on the opposite side of the valve channel16from where the section102is attached to the valve bag10.

The sealing device100can be installed in either direction over the valve channel16as shown inFIGS. 13 and 15. The width of the sections102and104, as well as the strips of adhesive108and protective covering110, must be sufficient to ensure enough adhesive covered surface area is available to securely seal the valve channel16, even if the outside sections do not exactly align after the valve bag10is filled.

Alternatively, another adhesive strip107, protected by a protective sheet, may be applied to the opposite side of the valve bag10from where the smaller section102is applied to the valve bag10. The adhesive strip107is aligned with valve channel16. Once the valve bag is filled and the protective surfaces covering the inner adhesive108of section104and the adhesive strips107are cleaned, the protective sheets are removed, as shown inFIG. 15, and the adhesive layer108is folded over the closed valve channel16and adhered to the adhesive strip107to securely seal the valve channel.

Another embodiment of the sealing device is shown in FIG.16. The sealing device140is typically much longer than the other embodiments of the sealing device described above. Sealing device140is very similar in construction to the sealing device100. The sealing device140is a single long piece that has a fold dividing sealing device140into two sections, a smaller section142and a longer section144. The smaller section142has an adhesive on its underside, but may or may not be covered by a protective sheet; whereas the longer section144will have a protective sheet covering its adhesive layer. A cross-section of the longer section144is shown inFIG. 17, the section144comprises a plastic or paper sheet146, an adhesive layer148and a protective covering149.

The smaller section142is attached to the valve bag10below the valve channel16by adhering it to the valve bag10before the valve bag10is filled. Once the valve bag10is filled and flattened, the valve channel16is folded closed, the surface of the valve bag10around the valve channel16is cleaned of dust and debris, the longer section144of the sealing device140is folded over the length of the valve channel, its protective covering149removed and the adhesive layer148on the under side of the longer section144is secured along the surface of the closed valve channel to ensure that it is securely closed. As with the sealing device100, an alternative adhesive strip145may be used to further ensure a consistent secure seal on the valve channel16.

Sealing Device for Sealing End Valve Tube

FIGS. 18 and 19show a typical valve bag200having an end valve channel or tube206. During assembly of the valve bag200, the short end pieces204and203are folded inward and the bottom side of the valve tube206is placed on top of the end piece204. The long end pieces202and207are then folded over the short end pieces204and203and the valve tube206as illustrated inFIGS. 18 and 19. The folded end pieces and valve tube206are held in place by the overlay208. One end of the valve tube206is open to the interior of the valve bag200and the other end is open to the exterior of the bag so that a fill tube can be inserted to fill the bag.

One embodiment of the sealing device205, shown inFIG. 20, is constructed similar to sealing device70, except that it is preferably annular in construction to fit snuggly within the valve tube206.

The sealing device205is made from a piece of soft plastic (preferably polypropylene or polyethylene) or paper that is folded in half lengthwise and the fold is perforated to tear when pushed against by a fill tube. A cross-section of sealing device205is shown in FIG.21. The sealing device205comprises a soft plastic or paper sheet282, an adhesive surface layer289on the back side of sheet282and an adhesive surface layer284on the top side of sheet282. The adhesive layer289on the backside of sealing device205is optionally covered with a removable protective covering287and the adhesive layer284on the frontside of sealing device205is covered with a removable protective covering286. If the adhesive layer289is a heat activated adhesive, it will not need to be protected with protective covering287. The adherence of the adhesive layer289to the sides of the valve tube206is accomplished by a variety of means known in the art such as glue or a heat or sonically activated adhesive.

FIG. 20shows sealing device205installed in the valve tube206of valve bag200. The sealing device205has two sections292and294separated by a perforated seam272.FIG. 20shows the sealing device205where the bottom side of section292is applied along the surface of the top side of the valve tube206and the bottom side of section294is applied along the surface of the bottom side of the valve tube206. To protect the adhesive layer284that is on the upper surface of sections292and294before its application to the point of desired contact, a removable protective covering286are placed over the adhesive layer284.

The sealing device205is installed before the valve bag200is filled. Once the sealing device205is installed in the valve tube206, the topsides of section292and294will be aligned on top of each other. A single sheet of protective covering286having a perforated seam272in the middle the protective covering286protects the adhesive layer284on the top surface of sections292and294. When the fill tube is pushed through the perforated seam272to begin filling the valve bag200, the protective covering286will basically split into two halves. Similarly to the protective sheet52shown inFIG. 5, the protective covering286may be designed to remain a single piece at its lower end by extending the protective covering286beyond the length of the valve tube206so that it can be more easily removed.

Alternatively the sealing device may be constructed of two sections of material, each section similar the section292of the sealing device205. In this embodiment the two sections of the sealing device may be separate pieces or may be constructed as a single piece300such as shown inFIG. 27in which a central section310separates two end sections302and304. A cross-section of sealing device300is shown in FIG.28. The sealing device300comprises a soft plastic or paper sheet320with an adhesive layer315on its underside. The adhesive layer315may or may not be covered with a protective sheet. The topside of the layer320, corresponding to the two end sections302and304, has adhesive layers316and318respectively. These two adhesive layers302and304are covered with protective sheets322and324respectively.

The sealing device300is installed into the valve tube206as it is being made. The sealing device is secured by adhesive to the inner surface of the valve tube206while it is a linear sheet before it is rolled into a tube. The sealing device300is secured to the valve tube206such that when the valve tube206is in a tubular configuration the end sections302and304are aligned so that one is on top of the other. The protective sheets322and324may be extended in length to ease their removal after the valve bag has been filled.

Valve bags200with the sealing device205or300in place are easily filled and sealed on the typical assembly line. The valve bags200are filled through a filling tube inserted into the valve tube206. Once the valve bag200has been filled, the top surface of the protective coverings286or322and324are cleaned by blowing a stream of air over them, by brushing dust and particles off of them, or by vacuuming them off. When the protective coverings286or322and324are clean, they are removed from the top surface of sections292and294or302and304. The top surface of sections292and294or302and304are then folded over each other and pressed together to form a consistent secure seal for the valve tube206. The width of the sections292and294or302and304, as well as the strips of protective coverings286or322and324, must be sufficient to ensure enough clean adhesive covered surface area is available to securely seal the valve tube206, even if sections292and294or302and304do not exactly align after the valve bag200is filled.

Fold Over Valve Tube Sealing Device

Another embodiment of sealing device250is designed to seal the valve tube206. The sealing device250, shown inFIG. 22is made from a piece of soft plastic (preferably polypropylene or polyethylene) or paper.

A cross-section of sealing device250is shown in FIG.23. The sealing device250comprises a soft plastic or paper layer210, an adhesive layer212on a portion of one end of the back side of layer210and an optional removable protective covering214on the bottom side of adhesive surface layer212. The portion of the layer210that is directly above the adhesive layer212has a smooth non-adhesive surface. At the opposite end of layer210, an adhesive layer216covers a portion of the top side of layer210and a protective sheet218covers the adhesive layer216. The adhesive layers216and214cover opposite ends of the layer210on opposed sides. Generally, the adhesive layers216and214will not cover the same section of the layer210and there may be a section of the layer210where no adhesive is applied to the top surface or the bottom surface of the layer210as illustrated in FIG.23.

The sealing device250is generally installed after the valve bag200has been made as shown inFIGS. 24 and 25. The adhesive layer212on the bottom side of the layer210is applied to the interior lower surface of the valve channel206to securely attach the sealing device to the valve channel206. Once the valve bag200has been filled, the protective sheet218is removed to expose the adhesive layer216. Then the sealing device250is folded over the overlay piece208and adhered to upper side of the overlay208to securely close the end of the valve channel206that opens to the outside. A partial cross-section of the upper end of valve bag200securely closed with sealing device250is shown in FIG.26.

Alternatively, another adhesive strip, protected by a protective sheet, may be applied to the end of the upper side of the overlay208where the sealing device250is folded over. The adhesive strip is aligned with valve channel206. Once the valve bag is filled and the protective surfaces covering the adhesive covering the overlay208and the adhesive layer216of the sealing device250are removed, the adhesive layer216is folded over the closed valve channel206and adhered to the adhesive strip covering that end of the overlay108to securely seal the valve channel.

The sealing device250may also be made a part of the valve bag200. In that case, the end of sealing device250opposite the adhesive layer216would be heat sealed or otherwise secured between the side204and the bottom outside surface of the valve channel206. The end of the sealing device250having the adhesive layer216and the protective sheet218would extend outward from the valve bag200. Once the bag had been filled and flattened, the outwardly extending end of the sealing device250would be folded over the overlay208, the protective sheet218removed, and the adhesive layer216secured to the upper side of the overlay208.

Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made to the described process, the materials used and the sealing system without departing from the spirit and scope of the invention as defined by the appended claims.