Abstract:
A plastic film fluid storage bag and dispensing spike assembly and method wherein the spike punctures the film and forms a fluid tight seal with the film surrounding a hole formed by the puncture. The film has no separate port structure for dispensing its contents. The spike may include a bulbous body with a sharpened tip at one end, an enlarged central portion, and a reduced diameter portion at its opposite end, adjacent a radially extending skirt. When seated, a seal is created around the smaller diameter portion of the body and against the skirt. The spike may alternatively include a cylindrical body with a slightly rounded point at one end and a radially extending skirt intermediate its ends. Finally, the cylindrical body spike may be used without a skirt. In all cases, a fluid passage extends through the body.

Description:
RELATED APPLICATION 
     This application is a continuation-in-part of application Ser. No. 09/188,764, filed Nov. 9, 1998, for a FLUID STORAGE CONTAINER AND DISPENSER, AND METHOD OF DISPENSING. 
    
    
     BACKGROUND OF THE INVENTION 
     Bags made of flexible material have been used since antiquity for the storage and dispensing of fluids. Wine and water storage bags made from animal skins are still in use, just as they were in antiquity. Latex rubber bags with attached hoses and probes found early use administering enemas in the medical field. All such bags have openings formed in them during manufacture for manually filling the bag with liquid, as well as for dispensing it. 
     In 1969 Baxter Laboratories introduced the first intravenous formula storage and dispensing bag. This bag differed from conventional bags in that the fluid was introduced in the manufacturing process and the bag was then sealed and sterilized for shipment to the customer. The bag offered a number of advantages over glass bottles previously used for this purpose. It was lighter, stronger and more compact, making it easier to ship and store. Because it was collapsible, it did not require a separate venting mechanism to allow air to enter as it was emptied. Elimination of the vent simplified the emptying process. No vent was needed in the administration set bag connector, either, and inadvertent administration of air to the patient was prevented. 
     The liquid formula in these prior art intravenous formula bags was normally dispensed with a dispensing spike which was forced through a dispensing port structure on the bag. The port structure was sealed into the bag during manufacture by laminating it between the two sheets of plastic film from which the bag was constructed. The port structure normally comprised a rigid plastic tube having an internal lumen obstructed by a thin, molded plastic septum. The spike, which was molded of rigid plastic, was used to puncture the septum. Fluid could then flow out of the bag through the spike. The spike was held in place by a friction fit in the lumen. 
     Generally, such a spike would be a component of an administration set designed to deliver the fluid to a patient or to some other container, or location, for use. In its most common form, the spike is connected to a length of plastic tubing. The tubing normally terminates with a connector designed to facilitate final delivery. In the case of an intravenous solution, the administration set connector is usually designed to be connected to a needle. 
     Incorporating a port in a bag in the aforedescribed manner remains the most common method of fabrication today. The method is effective, but relatively costly because of the need for a separate port structure and a secondary fabrication operation to seal the port structure between the two film layers of the bag. In addition, the seal area around the port structure has a tendency to leak. 
     Attempts have been made to improve dispensing systems for sealed bags by gluing a port structure to the outer surface of a bag. Such a system is illustrated in the Kuhn et al. U.S. Pat. Nos. Des. 361,838 and 338,726. In this system, the port structure has no internal septum, i.e., the bag wall is punctured by a dispensing spike. This greatly simplifies the fabrication of the bag because no port structure need be incorporated during fabrication. The elimination of a port structure which must be assembled with the bag is especially important with modern bag manufacturing technology where bags are formed, filled and sealed in a continuous, high speed process. By gluing the port structure onto the bag surface after forming, filling and sealing, manufacturing problems are greatly reduced. However, this system still requires a separate port structure, and an additional operation is needed to attach it to the bag by gluing, for example. 
     In the aforedescribed prior art systems the dispensing spikes are similar. They each have a sharp, piercing tip on one end of an elongated spike body containing a fluid passage. There is a very slight taper from the tip to a flange surrounding the body, and spaced from the tip, which serves as a stop. Retention, and a tight, non-leaking fit, are obtained by the friction fit of the spike body in the port structure. In one case, the spike pierces the bag wall itself. In the other case, the spike pierces a septum in the port structure. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a new and improved plastic film storage bag and dispenser for dispensing fluid from the bag. 
     Another object is to provide a new and improved plastic film storage bag and dispenser for dispensing fluid from the bag wherein the bag does not require a separate port structure which is integral with, or fastened to, the bag. 
     Still another object is to provide a new and improved plastic film storage bag and dispenser for dispensing fluid from the bag wherein the plastic film forms a fluid tight seal with the dispenser when the film is punctured by the dispenser. 
     A further object is to provide a new and improved plastic film storage bag and dispenser for dispensing fluid from the bag wherein the dispenser is a plastic dispensing spike which cooperates with the plastic film to form a fluid tight seal when the spike pierces the film and is seated. 
     Yet a further object is to provide a new and improved dispensing spike for plastic film storage bags. 
     Another object is to provide a new and improved method of dispensing fluid from plastic film storage bags. 
     The foregoing and other objects are realized in accord with the present invention by providing a plastic film storage bag and dispenser for dispensing fluid from the bag. The dispenser comprises a dispensing spike which penetrates the wall of the bag but does not require a separate port structure. 
     In a first embodiment of the invention, the spike includes a tear drop shaped body which terminates in a sharp point. The body pierces the film wall of the bag, point first. The body progressively stretches the film to form a hole of increasing diameter. After the largest diameter portion of the body passes through the film, the film around the hole progressively contracts elastically, following a bulbous face of the body until it reaches a reduced diameter end of the body, opposite the point. A skirt extends radially outwardly adjacent this reduced diameter end. The plastic film of the bag contracted around the hole grips the reduced diameter end of the spike between the bulbous face of the body and the skirt adjacent it. 
     With the spike inserted into the bag in this manner, the contracted film around the hole in the film forms a fluid tight seal with the reduced diameter circumference of the body between the bulbous face of the body and the skirt. The pressure exerted by the fluid in the bag is normally effective to press the film tightly against the skirt and increase the effectiveness of the seal while retaining the puncture spike even more securely in the bag. At the same time, the fluid pressure in the bag acting on the bulbous face of the body, where it faces the skirt, is normally effective to balance pressure acting on inwardly facing surfaces of the body and, accordingly, oppose the forces which would otherwise tend to expel the spike from the bag. 
     In one variation of the first embodiment, a fluid outlet passage extends longitudinally through the entire spike, opening through a flattened side of a conical tip on the body. In this variation of the invention, the conical tip is inclined to the longitudinal axis of the spike. 
     In another variation of the first embodiment, the fluid outlet passage is tee-shaped. The cross-passage of the tee opens through both sides of a conical tip which is concentric with the longitudinal axis. 
     In a modification of the spike embodying features of either of the aforedescribed variations of the invention, a circular strip of adhesive is placed on the flange, adjacent the reduced diameter end of the bulbous body. The inner diameter of the circular strip corresponds to the outer diameter of the bulbous body at its maximum diameter. The outer diameter of the strip is slightly less than the outside diameter of the flange. When the dispensing spike pierces the bag in the aforedescribed manner, the adhesive adheres to the outer surface of the bag to further enhance the sealing relationship between the flange and the bag. 
     In a second embodiment of the invention, the spike includes a straight cylindrical body which is joined to a conical tip by a curved profile transition section. The tip has a slightly rounded point at its free end. A fluid outlet passage in the spike is tee-shaped. A cross-passage of the tee opens through both sides of the transition section, immediately adjacent the cylindrical body. A skirt encircles the body a short distance from the transition section. 
     In a third embodiment of the invention the spike is substantially identical to the second embodiment, except that the skirt is eliminated. This embodiment of the invention finds particularly advantageous application as a built-in dispensing spike in a fluid dispenser unit. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention, including its construction and method of operation, is illustrated more or less diagrammatically in the accompanying drawings, in which: 
     FIG. 1 is a perspective view of a fluid storage bag assembled with a dispensing spike comprising a first embodiment of the invention; 
     FIG. 2 is enlarged sectional view through the plastic film from which the dispensing bag seen in FIG. 1 is fabricated; 
     FIG. 3 is a top plan view of the dispensing spike comprising a first embodiment of the invention; 
     FIG. 4 is a side elevational view of the spike shown in FIG. 3; 
     FIG. 5 is an end view of the spike shown in FIG. 3; 
     FIG. 6 is a longitudinal sectional view through the spike shown in FIG. 3; 
     FIG. 7 is an enlarged sectional view through one end of the bag and spike assembly illustrated in FIG. 1, with the spike shown in FIGS. 3-6 partially inserted; 
     FIG. 8 is a further enlarged sectional view of the bag and spike assembly shown in FIG. 7, with the spike fully inserted; 
     FIG. 9 is an enlarged view of the bag and spike assembly shown in FIG. 8; 
     FIG. 10 is a top plan view, similar to FIG. 3, showing a dispensing spike comprising a second embodiment of the invention; 
     FIG. 11 is a side elevational view of the spike shown in FIG. 10; 
     FIG. 12 is an end view of the spike shown in FIG. 10; 
     FIG. 13 is a longitudinal sectional view through the spike shown in FIG. 10; 
     FIG. 14 is a view similar to FIG. 11 showing an added seal feature of the invention on the dispensing spike of FIGS. 10-13; 
     FIG. 15 is an end view of the spike and seal feature shown in FIG. 14, ready for use; 
     FIG. 16 is an end view similar to FIG. 15 showing a protective element used on the seal feature prior to use; 
     FIG. 17 is a top plan view, similar to FIGS. 3 and 10, showing a dispensing spike comprising a third embodiment of the invention; 
     FIG. 18 is a side elevational view of the spike shown in FIG. 17; 
     FIG. 19 is a longitudinal sectional view through the spike shown in FIG. 18; 
     FIG. 20 is a top plan view, similar to FIGS. 3,  10  and  17 , showing a dispensing spike comprising a fourth embodiment of the invention; 
     FIG. 21 is a longitudinal sectional view through the spike shown in FIG. 20; and 
     FIG. 22 is a top plan view of the spike of FIGS. 20 and 21 combined in a dispenser according to the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings, and particularly to FIG. 1, a food formula bag and dispensing spike assembly embodying features of the present invention is seen generally at  10 . The assembly  10  includes a bag  11  formed of plastic film and a dispensing spike  12  molded of plastic. The bag  11  is filled with a liquid food formula F. The assembly  10  is shown in FIG. 1, immediately after the spike  12  has been inserted in the bag  11  but prior to food formula being dispensed. The dispensing spike  12  has a conventional dispensing tube  13  attached. 
     The bag  11  shown here is used as a container for food formulas where relatively long term storage is contemplated and where it is important to prevent admission of moisture or gas (normally oxygen) over such a term. To this end, the bag  11  is fabricated from a multi-layer plastic film  20 . 
     Referring to FIG. 2, the film  20  comprises a central layer  21  of ethylvinylacetate (EVA) which is 0.001 inches thick. This layer  21  has very high moisture and gas transmission resistance. Opposite sides of the central layer  21  are coated with thin layers  22  of Surlyn (a product of E. I. Dupont Nemours) which functions as an adhesive. Outside of the Surlyn adhesive layer  22 , on each side of the film  20 , is a low density polyethylene layer  23  which is approximately 0.0015 inches thick. The film  20  is, accordingly, 0.0045 inches thick. 
     The bag  11  is formed and filled in a conventional manner by what is known as a “vertical form, fill and seal” machine. In such a machine, a continuous sheet of the film  20  which is approximately twice the width of a bag  11  is fed (from a roll) through a hydrogen peroxide bath to sterilize it. Residual hydrogen peroxide is removed from the sheet. The sheet is then folded in half, lengthwise, so as to bring the two free side edges together. A continuous seal is made by impulse heating sealing along the two mating side edges. This fastens the edges together in fluid tight relationship and forms a tube. 
     A continuous seal is then also made across the tube at a predetermined location to form a fluid tight bottom in a bag created above this seal. A predetermined amount of formula is introduced into the tube from the open, upper end of the tube. The tube is then sealed above the liquid by impulse heat sealing it, in a manner previously described, across the folded sheet. The tube is cut through the middle of the top seal, leaving a filled, sealed bag below and the bottom seal of a new bag in the tube above. The process is then repeated with the new bag formed above. 
     The filled bag  11  is formed without an access port in it, according to the invention. When formula F is to be dispensed, the dispensing spike  12  is used to puncture the bag  11 , in a manner hereinafter discussed, creating the bag and spike assembly  10  seen in FIG.  1 . 
     Referring now to FIGS. 3-6, the dispensing spike  12  comprising features of a first embodiment of the invention is shown separately. The spike  12  is molded in one piece from plastic. The plastic is, in the present illustration, a polyamide, and the spike is relatively rigid when molded in a conventional manner. 
     The spike  12  shown here is 1.598 inches long. It consists of a tear drop shaped body  33  at one end and a dispensing pipe  34  at the other end, with a radially extending skirt  35  between them. The body  33  is 0.542 inches long, the pipe  34  is 1.000 inches long and the intervening skirt  36  is 0.056 inches thick. The diameter of the skirt  35  is 0.750 inches. 
     A fluid passage  37  extends longitudinally through the spike  12 , from an inlet  38  in the body  33  to an outlet  39  in the dispensing pipe. The inside diameter of the passage  37  is 0.114 inches. The outside diameter of the pipe  34  is 0.166 inches, making the wall of the pipe 0.052 inches thick. 
     The skirt  35  has a flat inner face  40  immediately adjacent the body  33  of the spike  12 . A bulbous face  41  of the body  33 , immediately adjacent and opposing the face  40 , is substantially semi-spherical in shape, with a radius of 0.143 inches. The face  41  curves inwardly from a maximum diameter of 0.286 inches at the outermost circumference  42  of the body  33  to a minimum diameter of 0.166 inches at an inner circumference  43  of the body  33  where it meets the face  40  of the skirt  35 . It will thus be seen that the body  33  is bulbous in shape and substantially larger in outside diameter than the pipe  34 . 
     Opposite the bulbous face  41  on the body  33  is a conical piercing tip  46 . The conical piercing tip  46  terminates in a sharp point  47 . The tip  46  is inclined slightly to the longitudinal axis of the spike  12  and has a flat face  48  on one side at an angle of 27° to the axis. This produces the somewhat elliptically shaped inlet  38  in the face  48 . The face  48  is 0.046 inches long, from one end at the point  47  on the tip  46  to the opposite end at  49 . The tip is 0.426 inches long between the point  47  and the outermost circumference  42  of the body  33 . 
     Referring now to FIGS. 7-9, the bag and spike assembly  10  and the method of inserting the spike  12  according to the invention are illustrated. As seen in FIG. 7, the spike  12 , with a dispensing tube  13  connected (to the pipe  34 ) and closed with a suitable clip (not shown), is pressed into the bag  11 , near the bottom of the bag. The sharp point  47  of the spike body  33  pierces the multilayer plastic film  20 . A hole  60  is formed in the film  20 , and that hole expands elastically as the spike body  33  penetrates. 
     When the spike body  33  has penetrated to the point where its maximum diameter has passed through the hole  60 , the elasticity of the film  20  causes the hole to contract and the film  20  around it to maintain a fluid tight seal  61   a  with the semi-spherical face  41  of the spike body  33 . The spike body  33  continues to penetrate until stopped by the face  40  of the skirt  35 , while the film  20  around the hole  60  continues to contract until then. At that point, the film  20  around the hole  60  is elastically gripping the spike body  33  at the circumference line  43  where the body  33  and skirt  35  meet to form a fluid tight seal  61   b  there. 
     As seen in FIG. 9, fluid pressure forces act on the body  33  when the spike  12  is in properly seated position. Fluid pressure forces acting on the film  20  are also illustrated in the same manner. The effect of fluid pressure forces A tending to expel the spike  12  are opposed by the forces B acting on the semi-spherical face  41  of the body  33  and tending to oppose expulsion. 
     It has been found that the effect of the elastic film  20  contracted around the hole  60  against the spike body  33  to form seal  61   b  normally is sufficient to prevent fluid leakage from around the spike  12 . This sealing is, however, enhanced by an additional seal  61   c  formed between film  20  and the face  40  of the skirt  35 . Fluid pressure forces C acting on the film  20  opposite this face  40  create this additional seal. The outer annular edge  62  of the face  40  is rounded off to prevent damage to the film  20  where it crosses this edge. 
     Referring now to FIGS. 11-13, a dispensing spike  112  comprising features of a second embodiment of the invention is shown independently. The spike  112  is again molded in one piece from plastic, preferably a polyamide plastic. 
     In this form of the invention, the spike  112  illustrated is also 1.598 inches long. It consists of a tear drop shaped body  133  at one end and a dispensing pipe  134  at the other end, with a radially extending skirt  135  between them. The body  133  is 0.542 inches long, the pipe  134  is 1.000 inches long and the intervening skirt  136  is 0.056 inches thick. 
     A tee-shaped fluid passage  136  extends through the spike  112 , from a transversely extending passage  138  in the body  133  to an outlet  139  in the longitudinal passage  137  through the dispensing pipe  134 . The inside diameter of the passage  137  and the passage  138  is 0.114 inches. 
     The outside diameter of the pipe  134  is 0.166 inches, making the wall of the pipe 0.052 inches thick. The diameter of the skirt  135  is 0.750 inches. 
     The skirt  135  has a flat inner face  140  immediately adjacent the body  133  of the spike  112 . A bulbous face  141  of the body  133 , immediately adjacent and opposing the face  140 , is substantially semi-spherical in shape, with a radius of 0.143 inches. The face  141  curves inwardly from a maximum diameter of 0.286 inches at the outermost circumference  142  of the body  33  to a minimum diameter of 0.166 inches at an inner circumference  143  of the body  133  where it meets the face  140  on the skirt  135 . 
     Opposite the bulbous face  141  on the body  133  is its conical piercing tip  146 . The piercing tip  146  terminates at a sharp point  147 . The transverse inlets  138  open to opposite sides of the conical piercing tip  146 , immediately in front of the outermost circumference  142  of the tip. The conical tip is 0.426 inches long between the point  147  and the circumference  142 . 
     The spike  112  is employed in exactly the same manner as the spike  12  previously discussed to penetrate a bag  11  and create a bag and spike assembly  10 . The only difference noticeable is a reduction in the amount of fluid leakage which takes place as the hole made by the tip in the bag film passes over the inlet ports to the passage  138 . This leakage, which is already minimal with the first embodiment of the invention (because the body  33  of the spike  12  pierces the film so rapidly), is reduced even further because the longitudinal dimension of each inlet port to the passage  138  is less than that of the inlet  38  in the first form of the invention. 
     Turning now to FIGS. 14-16 a modification of the spike  112  is illustrated. In this modification, a circular strip  181  of adhesive is laid on the face  140  of the skirt  135 . The adhesive strip  181  may be a preformed, double-side adhesive strip or it may be applied to the face  140  in liquid form, for example. In either case, a circular strip of wax paper  182 , which adheres only loosely to the adhesive, is laid over the adhesive strip  181  to protect it. 
     The wax paper strip  182  is split at  183 , and includes a pull tab at  184 . The inner diameter of the strip  182  is the same as that of the adhesive strip  181 , and corresponds exactly to the outside diameter of the spike body  133 . 
     The protective strip  182  is placed on the adhesive strip  181  immediately after the adhesive is applied. It is removed immediately prior to using the spike  112  to penetrate the bag  11 . 
     When a spike  112  which carries an adhesive strip  181  is driven into a bag  11 , the plastic film around the hole  60  created seats against the adhesive and creates an even more effective seal. This occurs only after the film has contracted around the face  141  of the body  133  to the inner circumference  143  as the spike  112  penetrates, however. 
     Referring now to FIGS. 17-19, a dispensing spike  212  comprising features of a third embodiment of the invention is shown independently. The spike  212  is also molded in one piece of a polyamide plastic. 
     In this form of the invention, the spike  212  illustrated is 1.825 inches long. It consists of a bullet shaped body  233  at one end and a dispensing pipe  234  at the other end, with a radially extending skirt  235  between them. The body  233  is 0.778 inches long, the pipe  234  is 0.972 inches long and the intervening skirt  235  is 0.075 inches thick. 
     A tee-shaped fluid passage  236  extends through the spike  212  from a transversely extending cross-passage  238  in the body  233  to an outlet  239  in the longitudinal passage  237  through the dispensing pipe  234 . The inside diameter of the passage  237  is 0.188 inches. The inside diameter of the cross-passage  238  is 0.134 inches. Thus, the cross-sectional area of the cross-passage  238  is one-half that of the passage  237 . With two branches, the cross-passage  238  has the same flow capacity as the passage  237  but, because their diameters are reduced, the potential for leakage during insertion is reduced. 
     The outside diameter of the pipe  234  is 0.288 inches, making the wall of the pipe 0.050 inches thick. The diameter of the skirt  235  is 0.750 inches. 
     The skirt  235  has a flat inner face  240  immediately adjacent the body  233  of the spike  212 . At the opposite end of the body  233 , a piercing tip  246  is formed. The tip  246  terminates in a rounded, i.e., segmentally spherical, point  247  having a radius of 0.025 inches. 
     The outer surface  241  of the front segment or tip  246  in the body  233  is conical in shape, as it extends rearwardly from the rounded point  247 , until it is 0.210 inches behind the point. This outer surface  241  of the front segment tapers outwardly at an angle of 15° to the axis of the spike  212 . 
     At an annular line on the outer surface  241  which is 0.210 inches behind the rounded point  247 , the surface of the intermediate segment in the body  233  begins curving inwardly until, at 0.655 inches behind the point, the surface  241  of the rear segment in the body  233  becomes circular cylindrical. The diameter of the tip in this circular cylindrical rear segment is 0.288 inches. 
     As best seen in FIG. 19, the cross-passage  238  opens through the outer surface  241  in the curved intermediate segment of the surface, i.e., just before the surface becomes circular cylindrical. This relationship of cross-passage  238  to the maximum diameter of the body  233  minimizes leakage during insertion. 
     Referring now to FIGS. 20-22, a dispensing spike  312  comprising features of a fourth embodiment of the invention is shown. In FIG. 22 the spike  312  is shown in combination with the base  335  of a dispenser cabinet (only partially shown) in which it is assembled. 
     The spike  312  is identical in configuration to the spike  212  previously described except, unlike the spike  212  it is machined from a steel rod. Since it is identical, corresponding reference numerals plus 100 digits are applied to corresponding components and no further description is included. The spike  312  is suited to repeated re-use without recognizable wear because it is fabricated of steel and not plastic. 
     In the spike  312  and dispenser base  335  assembly, the base takes the place of the skirt  235  in the third embodiment, for example. To utilize the assembly, a dispensing bag (not shown) is simply dropped into the dispenser, onto the spike  312 . The spike  312  pierces the bag and the dispenser is ready for use. 
     While preferred embodiments of the invention have been described, it should be understood that the invention is not so limited, and modifications may be made without departing from the invention. The scope of the invention is defined by the appended claims, and all devices that come within the meaning of the claims, either literally or by equivalence, are intended to be embraced therein.