Abstract:
A filling system for filling plastic bags and containers in an expedited and relatively dust-free manner. The filling system includes a coaxial tube having a supply passage for supplying a material and a return passage for drawing dust from the container during filling. The coaxial tube includes at least one aperture within the sidewall that extends into the return passage that forms a vacuum suction force against a wall of film surrounding the coaxial tube during filling of a container.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     I hereby claim benefit under Title 35, United States Code, Section 119(e) of U.S. provisional patent application Ser. No. 60/720,329 filed Sep. 22, 2005. The 60/720,329 application is currently pending. The 60/720,329 application is hereby incorporated by reference into this application. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not applicable to this application.  
       BACKGROUND OF THE INVENTION  
       [0003]     1. Field of the Invention  
         [0004]     This invention relates to filling systems for plastic valve bags and other types of containers typically used for filling flowable materials such as concrete products, pet foods, foodstuffs and other bulk products. It may also be used for other types of products that may not be considered flowable such as any number of hard and soft goods like briquettes, medical devices, and so on. More specifically, this invention relates to filling these plastic bags and containers in a unique method that provides a dust-control filling environment and may speed up the filling process.  
         [0005]     2. Description of the Related Art  
         [0006]     Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.  
         [0007]     Presently there are many types of heavy duty bags and containers and several methods in which they are filled. These bags and methods include paper and plastic valve bags filled on nozzles, stitched bags, top load and seal, bags that are top filled and glued closed, and an assortment of rigid containers that may accept a fill nozzle type of system. Generally speaking, these bags are put up in larger sizes to handle loads from a few pounds up to as many as 100 pounds. Various forms of bags and containers may be substantially more.  
         [0008]     Most bags used with cement and concrete products and other heavy flowable contents are paper valve bags like those commonly seen palletized in home improvement centers throughout the U.S. and contain products sold to consumers for use in home garden and yard applications, such as 60# mortar and concrete mix and 94# cement and concrete mix. The chief reason paper valve bags are used for these applications is primarily due to per unit cost and productivity factors. Paper valve bags cost more than standard, top-loading plastic bags but the paper valve bags are faster to fill thus they substantially improve productivity and output. There has been some limited use of plastic valve bags made from a woven polypropylene—especially in Europe—with similar productivity. In the U.S. and other countries where paper is still relatively inexpensive, the polypropylene valve bags cost 20% to 30% more than paper. Another form of plastic valve bag is that cited in my pending patent application US20040184680, which costs less than both the paper and polypropylene valve bags and have many advantages over the two. Various forms of containers may include commonly used cardboard cartons, rigid plastic containers and even forms of bottles, buckets and so on.  
         [0009]     One significant problem associated with the filling of flowable contents with the aforementioned bag and container types and the aforementioned systems is the amount of dust that is generated during the filling process. In any top loading system fugitive dust tends to drift upwards, then float away and settle nearby. The most commonly used valve bag filling system used today is that of placing a valve bag on a nozzle whereas the valve is in a horizontal disposition as illustrated in U.S. Pat. No. 4,589,454, which uses a conventional valve bag such as that of U.S. Pat. No. 4,759,641. When a valve bag is filled according to this methodology, fugitive dust escapes from the bag and filling system in three ways. First, during the fill process, it escapes from vent holes in the bags. Since current filling methods use injected air or are air assisted, they require bags to have vent holes in order to allow the injected air to escape. The injected air (which may also be referred to as trapped air in the case of a gravity feed system) contains the fugitive dust. This dust is emitted directly into the environment where the bag filling operator works. Second, once the bag has been filled to the designated weight, the bag is ejected from the nozzle and a “puff of fugitive dust” is emitted from the nozzle. Obviously this puff of dust drifts outward, and again, into the environment where the operator works. Third, after the bag is filled and ejected from the nozzle, the valves on prior art paper and plastic bags tends to remain partially open and during its drop to the conveyor belt system below and transportation away from the fill station additional fugitive dust is emitted. The exception to this rule is the valve bag of the US &#39;680 application that provides a relatively leak proof seal once the bag has been filled with its contents.  
         [0010]     In addition, fugitive dust leaks out of prior art paper and polypropylene valve bags and stitched bags after they are filled. During the palletizing process and through subsequent handling, dust continues to escape from the leaky valves, vent holes, and through the porous paper material. All told, bag packing facilities using existing bag filling technologies are notoriously dusty environments. This stray dust is also a problem for distributors and retailers, as may be seen at any home improvement center selling concrete products.  
         [0011]     Perhaps what is of most concern with the fugitive dust associated with materials such as concrete is its toxicity. The dust associated with concrete products contains lime and federal law requires companies to print warning labels on bags. Other toxins in other forms of flowable filling applications may include herbicides, fungicides, carbon black, drug-related chemicals and so on. Due to this inherent danger, most bag packaging facilities (and state or federal laws), require employees operating the filling systems to wear dust-control masks to help screen out the fine particles. Presently this relatively dusty filling environment is considered the best available technology otherwise it would probably be illegal to subject employees to such a large volume of potentially harmful toxins.  
         [0012]     The only system that partially addresses the serious issues previously described is that of U.S. Pat. No. 4,471,820, Lepisto, and its related issued patents. It discloses a means of using blasts of high and low pressure air and subsequently a vacuum to remove dribblings that may be suspended in a valve sleeve. However, it does not prevent the overall loss of fugitive dust through vent holes or leaky valves during or after the fill process. Furthermore the system of the &#39;820 patent negatively affects productivity as additional time is required to clear the nozzle with the blast of high pressure air then a second blast of low pressure air to suspend the dust particulate (suspended dribblings) and subsequently, the employment of a vacuum in order to remove the suspended dribblings. Another problem with this rather elaborate system would be the cost to replace the fill nozzle. Since they commonly wear out rather quickly, in a matter of weeks even, the expense to replace the sophisticated fill nozzles would be virtually cost-prohibitive, thus allowing cheaper competition to thrive.  
         [0013]     When filling rigid containers similar dust control problems are generated. Whether the rigid container is a 55-gallon drum, a cardboard carton or some form of plastic container, the emission of dust can be a troubling problem. This type of problem is evident in medical clean room operations and any number of chemical plant operations.  
         [0014]     A filling system that can reduce or eliminate the fugitive dust during the filling process would be desirable. Furthermore, if the system also had a means to control the air and its fugitive dust after it was filled, it too would be highly desirable. Ideally, the system would not have a negative effect on productivity. Such a system may also eliminate the need for vent holes in bags and allow the use of the more desirable valve bag as described in the US &#39;680 application. It would also allow for the use of rigid containers that would be constructed with similar air tight qualities.  
       BRIEF SUMMARY OF THE INVENTION  
       [0015]     The dust control problems associated with prior art are substantially reduced and may be eliminated with the present invention. The solution to dust control is through containment. The filling system of the present invention accomplishes that by using a method to mount a valve bag onto a fill nozzle that has a second internal chamber suitable to neutralize any air that may be injected during the fill process. It may also be accomplished by inserting the nozzle into a bag or container. Thus, once a bag is mounted or a nozzle is inserted into a container, the neutralized air with its inherent dust content may be extracted and disposed of as desired. The result of such a system may eliminate the requirement for vent holes and may also eliminate the “puff of dust” that is emitted from the nozzle after filling.  
         [0016]     In the present invention, we accomplish these objectives by using a fill nozzle that allows a valve bag or other form of aperture to firmly affix itself. The fill nozzle also uses a narrowed tip to allow for easier mounting of a bag valve or insertion of the nozzle. Last it may incorporate an air control system that in combination with the other attributes to be revealed, creates not only a dust free filling environment, but uses both negative and positive air to control the resident air and its inherent fugitive dust, and direct it elsewhere for future use.  
         [0017]     The objectives of the present invention include: 1) a method of preventing fugitive dust from escaping into the work environment during the bag or container filling process; 2) a method of handling resident air that contains potential fugitive dust that is inherent to filling a bag or container with flowable contents; 3) a method of capturing the fugitive dust contained in the resident air; 4) a method of storing the fugitive dust for later use and applications; 5) a method of using air control to maintain a valve bag in position while being filled on a nozzle; 6) a method of releasing the valve bag after it has been filled; 7) a nozzle that helps prevents fugitive air from escaping; 8) a nozzle and system that provides for escape and/or control of resident air and fugitive dust; 9) a nozzle with replaceable inner feed tubes; 10) a nozzle with replaceable outer sleeves; 11) a method of controlling the displacement of air that may otherwise be captured inside a bag or container; 12) a method to recapture the dust contained in the “puff of dust” emitted during the fill process, and; 13) a method of utilizing positive and negative air in the bag or container filling process.  
         [0018]     Other objects and advantages of the present invention will become obvious to the reader and it is intended that these objects and advantages are within the scope of the present invention.  
         [0019]     To the accomplishment of the above and related objects, this invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that changes may be made in the specific construction illustrated and described within the scope of the appended claims.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]     Various other objects, features and attendant advantages of the present invention will become fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein:  
         [0021]      FIG. 1  is a perspective view of a fill nozzle and system of the present invention.  
         [0022]      FIG. 2  is a perspective view of a valve bag as described in my pending US &#39;680 application.  
         [0023]      FIG. 3  is a perspective view of the bag in  FIG. 2  mounted on the fill nozzle and system of  FIG. 1  whereby positive and negative air is being used to control air, dust, retention and release of the bag.  
         [0024]      FIG. 4  is a perspective view of a valve bag being released from the present invention.  
         [0025]      FIG. 5  is a perspective view of a nozzle of the present invention being used to fill a rigid container.  
         [0026]      FIG. 6  is a vertical cross-sectional view of the nozzle of the present invention cut in half and illustrating the replaceable outer sleeve and replaceable inner feed tube.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0027]     In  FIG. 1  fill system  10  consists of fill nozzle  12 , which has an internal hollow feed tube  14  where a flowable material (not shown) may enter at rear entry point  16  and be fed into the bag or container out of the forward most point  18  as illustrated in  FIG. 3 . Nozzle  12  has an outer sleeve  20  with its forward most point  22  being a generally pointed tip and is smaller than rear portion  24 , thereby forward most point  22  is suitable for insertion into a valve or container (or having a bag or container mounted thereon). Between hollow feed tube  14  and outer sleeve  20  is air space  26  whereas air flow will be utilized to control various aspects of the present invention, to be described later. In sleeve  20  in a generally forward location that would be placed inside a bag or its valve (once the nozzle is inserted as in  FIG. 3 ) or inside the fill aperture of a container ( FIG. 5 ) are communication apertures  28   a,    28   b,    28   c  and  28   d  (not shown) allowing for air flow between air space  26  and the inside of the bag or container or at times vacuum suction against a wall of film. Air space  26  flows into manifold  30 , which is located rearward and has an exit port  32 . Downstream from exit port  32  in pipe assembly  33  is valve  34  where positive air P may enter and a second valve  36  where negative air N may exit as illustrated by the corresponding arrows indicating the directional flow). The feed tube  14  on this type of nozzle would typically be anywhere from 1″-3.5″ ID depending on whether it is filling a small quantity of finer granules or bulkier items such as charcoal briquettes or even larger, bulkier items. The outer sleeve  20  would be a suitable dimension larger than inner feed tube  14  sufficient to create air space  26 . The intention of the present invention is not to restrict the size or type of contents being filled, but to control the air flow and resident dust. Air space  26  may also be suitable for use of controlling other forms of gases in addition to air containing dust, for example gases used in food processing or other applications using gas for preservation or moisture control purposes, but not limited to these. Fill nozzles, sleeves and feed tubes are usually made of steal, but may be made of other types of material such as plastic or aluminum that can be formed into the desired tubular shape, round or otherwise. Likewise, the outer sleeve and the inner fill tube may be made so that they are easily replaceable in any number of existing methodologies, such as being secured by screws, using a keyed twist and turn locking means, affixing them in place with a collar, and so on. There is no requirement that the fill nozzle is tapered or which portion may be tapered, only that it is preferable to have it tapered along a front, mid or rear portion in order to effect a snug fit. The tapered nozzle provides a simple method to achieve an air tight seal between the fill system and the valve or container being filled, however, this may also be accomplished with a non-tapered fill nozzle system and with a valve that is tapered instead. Likewise, both the nozzle and the valve may be tapered to improve the air tight seal. There is also no requirement that the outer sleeve and inner feed tube be two separate components, they may be manufactured or assembled to be one and the same, with a built-in air space that communicates with the rest of the system. In such a system, it would function substantially the same as described herein.  
         [0028]     In  FIG. 2  prior art valve bag  40  has a top  42 , a bottom  44 , left and right side gussets  46  and  46 ′ respectively, with left and right side center gusset creases  48  and  48 ′ respectively. Both bag top  42  and bottom  44  are sealed. Extending inwards from left side center gusset crease  48  are internal flaps  50  and  52  (not shown as it lies directly underneath internal flaps  50 ). Internal lap sealed portion  54  (shaded line) is a narrow sealed strip that lies adjacent left side center gusset crease  48  and runs continuously from bag bottom  44  upward then turns inward at point  56  and stopping at point  57 . Valve opening  58  is the unsealed portion that lies along left side center gusset crease  48  in between point  56  and bag top  42 , and is suitable to allow entry of the fill nozzle described in  FIG. 1 . Typically, internal flap portions  50  and  52  extend inward, inside bag  40  about 2″ to 3″ from center gusset crease  48 , depending upon bag size, but could certainly be more or less. Seal portion  60  begins at point  56  and runs approximately horizontal, but may taper upward slightly upward into internal flap portions  50  and  52 . The area between horizontal seal  60  and sealed bag top  42  forms a tapered valve sleeve  62 , which sleeve along with valve opening  58  will fit snugly about a nozzle such as that of sleeve  20  of fill nozzle  12  in  FIG. 1 . This tapered fit helps keep air and its accompanying flowable material dust particles from escaping, such as that which accompanies cement and concrete byproducts. A tapered valve as described herein works best in combination with the tapered fill nozzle of  FIG. 1 , as it will seat itself along the entire valve surface to the tapered nozzle surface however, it is not absolutely essential. This is one form of bag that may be used on the fill system of the present invention albeit there are other types of prior art valve bags suitable for use on the system as well.  
         [0029]     In  FIG. 3  the system described in  FIG. 1  is in operation. The nozzle  12  has been inserted into bag valve opening  58  of bag  40  and seating valve sleeve  56  firmly against and around nozzle sleeve  20 . Flowable material F (the many pellets illustrated) was processed through feed tube  14  as it entered feed tube  14  at rear entry point  16  and exited at forward most point  18 , thereby being delivered into bag  40 . This process may come from any number of methods, for example a auger feed, gravity feed, air assisted and so on. It is noted that bag  40  is being retained firmly in position on nozzle  12  by the a vacuum created at communication apertures  28   a  and  28   b,  a result of the negative air flow inside air space  26  and throughout the system of the present invention. This negative air flow was created by the use of positive air entering valve  34  and exiting from valve  36  as previously described. The suction at communication apertures  28   a  and  28   b  against film wall surfaces  29   a  and  29   b  which lie generally above and adjacent said apertures, affixing and retaining bag  40  firmly on nozzle  12  while it is being filled with contents. Apertures  28   a  and  28   b  may also be placed further rearward so that the lie under valve sleeve  56  with substantially the same effect of retaining the bag on the fill nozzle. The ease of mounting a bag and having it be rapidly affixed on a nozzle also saves valuable time, improving output and productivity. It makes an easy task for an operator to quickly slip a bag on a nozzle having the suction promptly retain it to the nozzle and then quickly move to the next nozzle in line and mount a valve bag on it. As previously described in  FIG. 1  and herein in  FIG. 3 , additional resident air accompanies the flowable contents filling the bag either by being an inherent part of the contents thereof or being a part of an air-assist or air-injection filling process. This resident air enters at point  16  of feed tube  14  and exits into the bag at point  18 . During this filling process, the excess resident air that accompanies the flowable contents or is being injected along with it, is being neutralized by the negative air system as it enters communication apertures  28   c  and  28   d  (not shown), then moves rearward through air space  26  into manifold  30  and last, exits out exit port  32  and past valve  36 . Excess air, with its dust content, is extracted in the direction indicated of arrow N (negative air flow) and sent to another station (not shown) for further processing. By properly neutralizing the amount of resident air in the contents during the fill process, bag  40  does not balloon up, nor are any vent holes in the bag required to allow the excess resident air to escape. The amount of negative air pressure in the system of present invention is directly related to the amount of excess resident air in the contents being filled or being injected. Thus, the filling process may be relatively air tight with excess resident air and its inherent dust being transferred out of exit port  32 , through tube  37  and subsequently contained or recycled. This containment may be in the form of a bag house, fill hopper, silo and so on. It may also be fed directly back into the fill system itself. The simplicity of the system of the present invention provides high volume productivity since the negative air adjustment may be easily adjusted or even automated through any number of existing mechanical, computer, microcontroller methodologies, and so on.  
         [0030]     In  FIG. 4  the present invention is communicating with a means (not shown) of releasing or dispensing the filled bag from the nozzle by providing temporary stoppage of the negative air flow, thereby ceasing the vacuum at communication apertures  28   a  and  28   b,  which allows bag  40  to slide off, or removed from, nozzle  72 . In this example nozzle  72  is tilted downward at a 15 degree angle as illustrated and upon cessation of the negative air flow, gravity causes bag  40  to simply slide off. Upon release from nozzle  72 , valve sleeve  56  of bag  40  flattens out, thus closing off the valve opening. As the case may be, it may be advantageous to mount nozzle  12  slightly downward at a 12 degree to 18 degree angle or, the release process may be effectuated by manual removal from a horizontally mounted nozzle or by a mechanical tilting downward of a horizontally mounted nozzle. Even if the nozzle were to be inserted into a valve bag directly downward, cessation of the negative air and releasing a valve from a nozzle may be accomplished in much the same manner. Regardless of the methodology used, regardless of the angle, or lack of angle of a fill nozzle, the effect is substantially the same. The stoppage of negative air may be effected by an number of means such as mechanical, computer, microcontroller methodologies and so on. Any number of events may trigger the release of a bag, but the most common one would be initiation by a bag reaching a predetermined weight.  
         [0031]     In  FIG. 5  rigid container  60  has four sides  62   a,    62   b,    62   c  (not shown) and  62   d  (not shown), a top  64 , a bottom  66  (not shown) and a receiving aperture  68 . Nozzle  82  is shown inserted into receiving aperture  68  whereas the filling process is much like that of the preceding bags. Upon filling the container with its contents, nozzle  82  will be extracted, receiving aperture  68  will close, much like that in the preceding bag, and container  60  will be further processed for shipping.  
         [0032]     In the cross-sectional view in  FIG. 6 , which cuts vertically down the middle of nozzle  92  thereby cutting the nozzle in half lengthwise, outer sleeve  100  is attached by screws  140  and  140 ′ to manifold  130  at flange  138 , thus making outer sleeve  100  replaceable. Inner feed tube  94  is also made replaceable by a key-lock method inserting groove  142  into locking pin  144  and twisting clockwise until secured in place. The method of securing a replaceable outer sleeve or inner feed tube to the system may be accomplished in any number of ways and the present invention is not intended to be restricted to only those shown herein. Likewise, the out sleeve and inner feed tube may be one and the same and together they may be replaceable as well.  
         [0033]     As to a further discussion of the manner of usage and operation of the present invention, the same should be apparent from the above description. Accordingly, no further discussion relating to the manner of usage and operation will be provided.  
         [0034]     With respect to the above descriptions then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.  
         [0035]     Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.  
         [0036]     What has been described and illustrated herein is a preferred embodiment of the invention along with some of its variations. The terms, descriptions and figures used herein are set forth by way of illustration only and are not meant as limitations. Those skilled in the art will recognize that many variations are possible within the spirit and scope of the invention, which is intended to be defined by the following claims (and their equivalents) in which all terms are meant in their broadest reasonable sense unless otherwise indicated. Any headings utilized within the description are for convenience only and have no legal or limiting effect.