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DISPENSING CARTRIDGE FOR FLOWABLE
BACKGROUND OF THE INVENTION
The field of the invention relates generally to dispensing devices for delivering flowable materials such as liquids, solutions, dispersions, suspensions, gels, pastes and other fluids. More particularly, the field of the invention relates to a dispensing system for delivering multiple doses of flowable materials and for preventing the influx of external 10 contaminants during and between deliveries.
The dispensing of flowable materials in a contaminationsafe manner, especially over prolonged periods of time or in a repetitive manner, e.g., in multiple doses, presents many difficulties. The main problems relate to precise flow control and prevention of back flow or reflux. In fact, external contaminants easily can enter a container with the back flow at the end of the delivery cycle.
Most collapsible containers for flowable materials have a 2Q discharge port such as a hole, nozzle, spout or other type of opening. The contents such as pastes, liquids or other fluids exit through the discharge port propelled by internal pressure.
This method of dispensing the flowable material is fre- 25 quently inaccurate and does not prevent the entry of external contaminants into the container. Hence, additional pouring or dispensing devices are surmounted on the discharge port when precise control of the dispensing characteristics is desired. These devices must be simple, effective and low- 30 cost, especially if intended for widespread commercial and domestic use.
Typically, a dispensing apparatus has a valve mechanism to ensure precise delivery. In U.S. Pat. No. 5,033,655 Brown teaches how to dispense fluid products from a non- 35 collapsible container by employing a system with a slit valve. The system admits air to prevent the collapse of the container as fluid is delivered to the user. Thus, external contaminants borne by air are forced into the solution remaining in the container. Clearly, such dispensing appa- 40 ratus is not suitable for contamination-safe dispensing from collapsible containers.
A simple solution in the form of a squeeze valve with augmented sealing is presented by Vorhis in U.S. Pat. No. 5,265,847. This apparatus is adapted for containers whose 45 contents are expelled under the force of gravity. In U.S. Pat. No. 5,099,885 Nilsson discloses a flapper valve, which delivers viscous fluids by means of a pump. This solution is not applicable to all types of liquids and fluids. Likewise, in U.S. Pat. No. 5,346,108 Pasinski discloses a gauged dis- 50 pensing apparatus to deliver a predetermined amount of generally viscous fluid. The apparatus has a flexure with a bi-stable orientation, concave to convex. Airborne contaminants can enter the apparatus as the flexure returns to its original position. In addition to the shortcomings already 55 mentioned, the above conventional solutions to the problem of preventing airborne contaminants from entering a flowable medium are not specifically designed to prevent back flow. Haviv teaches in his U.S. Pat. No. 5,080,138 a valve assembly relying on a sleeve valve and consisting of mul- 60 tiple components. Back flow is thwarted by a sheath which permits the flowable to flow out of the valve but prevents any back flow into the container. Unfortunately, this device is complicated, costly to manufacture and difficult to assemble. 65
Asimple discharge nozzle is presented by Latham in U.S. Pat. No. 5,398,853. The nozzle is adapted for the delivery of
pastes, e.g., toothpaste. Although Latham does attempt to eliminate the transfer of germs between the discharge opening and the secondary surface where the paste is applied, his nozzle will not arrest the influx of bacteria. For example, bacteria can enter when the nozzle is immersed in a solution.
More effective methods of contamination-free dispensing are disclosed in U.S. Pat. Nos. 5,305,786 and 5,092,855 issued to Debush and Pardes respectively. Debush discloses a modification to the applicant's prior U.S. Pat. No. Re. 34,243 relying on an expandable elastomeric sleeve tightly fitted about a valve body with entry and exit ports. Debush's improvement is aimed at simplifying the assembly. Unfortunately, his solution requires more material to manufacture the valve. In addition, it is difficult to produce a discoid-shaped valve for this invention and adapt the apparatus to collapsible containers. Pardes discloses a rigid enclosing sleeve to retain the elastomeric sheath against the valve body, thus providing a seal between the sheath and the valve body. This is closely related to the applicant's teaching in U.S. Pat. No. Re. 34,243. Pardes'valve operates through two sets of ports within a valve body, thus rendering the device unnecessarily complex.
None of the known conventional dispensing devices are low-cost, simple in construction and capable of delivering a flowable material ranging from low to high viscosity. Furthermore, conventional devices can not be easily adapted to collapsible containers, i.e., containers which do not produce an internal vacuum when their contents are expelled.
In view of the above discussion, what is needed is a contamination-safe multiple-dose dispensing cartridge for dispensing a flowable material from a collapsible container.
Furthermore, the dispensing cartridge of the invention should thwart the back flow or reflux of the flowable material. This will prevent external contaminants from entering the container through the dispensing cartridge during and after delivery of the flowable material.
What is also needed is a dispensing system which provides a contamination-safe cartridge that is simple in construction and easy to mount on various types of collapsible containers. Further aspects and advantages of the invention will be elucidated in the detailed description.
SUMMARY OF THE INVENTION
A multiple-dose dispensing cartridge is designed to dispense a flowable material from a collapsible container, i.e., from a container of the type which does not produce an internal vacuum as the flowable material is dispensed. The cartridge prevents external contaminants from entering the container by virtue of its construction. In particular, the cartridge has a housing and an attaching mechanism for attaching the housing to the delivery port of the container in an air-tight manner. A delivery block located inside the housing has an input port for receiving the flowable material exiting the container through the delivery port. An internal channel commencing at the input port and terminating in at least one output port runs through the delivery block. A flexible sheath envelops the delivery block such that a portion of the sheath covers the output port or ports to thus produce one or more sleeve valves permitting only the outflow of the flowable material from the output port or ports.
In a preferred embodiment the cartridge has an outlet valve formed by an end of the flexible sheath downstream of the one or more sleeve valves. The outlet valve also permits only the outflow of the flowable material. Typically, the outlet valve formed by the end of the sheath is a duck bill
valve, a slit valve or a flapper valve. In another embodiment the outlet is formed by the end of the flexible sheath without creating an actual valve.
Finally, the cartridge of the invention has a dispensing port in the housing for dispensing the flowable material 5 exiting from the outlet valve or outlet created by the flexible sheath.
The cartridge of the invention can be mounted on collapsible containers such as tubes, bags, infusion containers, syringes, pouches, collapsible reservoirs, bellows-type con- 1° tainers and the like. The attachment mechanism will depend on the type of container and may generally be constituted by an adhesive seal, a screw-on neck, a press-fit neck, a bonding seal, a heat seal or other joining material or element.
The housing is preferably made of a moldable material 15 and is rigid. This is necessary to arrest the expansion of the flexible sheath and prevent abrasion of the sheath as the flowable material is being dispensed. The flexible sheath is preferably made of a moldable thermoplastic elastomer. Exemplary materials which can be utilized in making the 20 sheath include styrene-butadiene styrene, silicone, urethane, rubber and the like. Furthermore, the sheath is affixed on the delivery block to prevent slip-off and ensure proper operation of the sleeve valve or valves. This can be accomplished with an O-ring and a corresponding groove formed in the 25 delivery block or a protrusion in the sheath for fitting into an analogous groove in the delivery block. Alternatively, the sheath is pinched between the delivery block and the housing. In all cases, however, the inner diameter of the sheath in undistended state is smaller than the outer diameter of the 30 delivery block. By virtue of this provision the sheath will fit tightly around the delivery block. The preferred range of inner diameters is 0.5 to 0.8 times the outer diameter of the delivery block.
The cartridge of the invention is effective in preventing 35 the entry of air and its constituents, oxygen, nitrogen, water vapor and other atmospheric gases as well as other air-borne contaminants including smoke, dust, pollen and microorganisms. Thus, the contents of the collapsible container is protected from degradation due to these types of external 40 contaminants. In a particularly advantageous embodiment of the invention, the dispensing cartridge can be permanently bonded to the container, e.g., by the manufacturer such that the container and cartridge constitute an integrated dispensing system. 45
The invention will now be explained in more detail with reference to the attached drawing figures.
DESCRIPTION OF THE FIGURES
FIG. 1 is a three dimensional sectional view of a dispens- 50 ing cartridge according to the invention.
FIG. 2 is a cross sectional view of the dispensing cartridge of FIG. 1 before delivery.
FIG. 2A is an enlargement of a portion of FIG. 2 as shown. 55
FIG. 3 is a cross sectional view of the dispensing cartridge of FIG. 1 during delivery.
FIG. 3A is an enlargement of a portion of FIG. 3.
FIG. 4 is a three dimensional view of the tip portion of the g0 cartridge of FIG. 1.
FIG. 5 is a three dimensional view of a portion of the outlet valve.
FIG. 6 is a three dimensional view of a delivery block for the cartridge of the invention. 65
FIG. 7 is a plan sectional view of a dispensing cartridge according to the invention mounted on a tube.
FIG. 8 is a plan sectional view of a dispensing cartridge according to the invention mounted on a syringe.
FIG. 9 is a cross sectional view of a dispensing cartridge according to the invention without an outlet valve.
FIG. 10 is a cross sectional view of another dispensing cartridge without an outlet valve.
FIG. 11 is a cross sectional view of yet another dispensing cartridge according to the invention mounted on a bellowstype container.
A preferred embodiment of a dispensing cartridge 10 assembled in a housing 12 is shown in FIG. 1. Conveniently, housing 12 is made of a moldable material which is rigid and inert. In this case cartridge 10 is mounted on a collapsible container 14, of which only the top portion is shown. It should be noted that in the figure cartridge 10 is much larger than a neck 16 of container 14. In practice it will be oftentimes desirable to considerably reduce the dimensions of cartridge 10, e.g., to constitute a small extension of neck 16 or protrude into or be embedded in neck 16. In the embodiment shown neck 16 has a neck threading 18 which cooperates with a cartridge threading 20 on the lower portion of housing 12. Thus, cartridge 10 is mounted on container 14 in an air-tight manner by screwing housing 12 onto neck 16.
A flowable material 22 is stored in container 14. Typically, material 22 is a liquid or fluid which requires careful dispensing and protection from external contaminants 26. These contaminants 26 can be broken down into particulates or other matter 28 such as air and its constituents, oxygen, nitrogen, water vapor and other atmospheric gases as well as other airborne contaminants including smoke, dust, pollen and microorganisms. The last group consists of yeasts, molds, bacteria, protozoa and diverse viruses. Many flowable products, such as medicines, chemicals, health-care materials, personal hygiene materials, edibles and other flowable goods require protection from at least one of the above-listed contaminants 26. These products are encountered in domestic, commercial and industrial settings.
Neck 16 terminates in an opening or delivery port 24. Flowable material 22 exits container 14 through port 24 to enter dispensing cartridge 10. In particular, cartridge 10 has a delivery block 30 whose lower portion exhibits an input port 32 for receiving material 22. Delivery port 24 is pressed firmly and tightly against the bottom of delivery block 30 when cartridge 10 is mounted on container 14. In this way delivery port 24 feeds directly into input port 32.
Delivery block 30 has an internal channel 34 commencing at input port 32 and terminating in two output ports 36 and 38. In fact, channel 34 splits into two branches 40 and 42 leading to output ports 36 and 38 respectively. In this embodiment output ports 36 and 38 are arranged on diametrically opposite faces of delivery block 30. This geometrical placement of ports 36 and 38 is preferred because it is easily manufactured and ensures their largest circumferential separation.
A flexible sheath 44 stretches over or envelops delivery block 30. Preferably, the material of flexible sheath 44 is a moldable thermoplastic elastomer. Although a person with average skill in the art will be able to find other suitable elastics, the most preferred ones include styrene-butadiene styrene, silicone, urethane and rubber.
To ensure that sheath 44 fits tightly around delivery block 30, it is important that in the undistended state the inner
diameter of sheath 44 be smaller than the outer diameters of block 30. This way, once sheath 44 is slipped over delivery block 30, it will stretch to tightly envelop delivery block 30. In fact, it has been determined that the inner diameter of sheath 44 in the undistended state should most preferably 5 range from 0.5 to 0.8 times the outer diameter of delivery block 30. The taut fit around block 30 achieved at this diameter differential will ensure good operation of sleeve valves 46 and 48 described below.
Another provision for securing sheath 44 in place over 1° delivery block 30 includes an inward bulge or protrusion 50 extending circumferentially around delivery block 30. Correspondingly, delivery block 30 has a groove 52 for receiving protrusion 50. Sheath 44 is securely fixed when protrusion 50 is lodged or seated in groove 52 along the :5 circumference of delivery block 30. In other words, protrusion 50 serves the role of an attaching means for affixing sheath 44 to delivery block 30 below output ports 36 and 38.
When properly mounted, sheath 44 extends over the sides of delivery block 30 thus covering both output ports 36 and 20 38. This produces two sleeve valves 46 and 48 at the locations where ports 36 and 38 are covered. By their nature, sleeve valves 46 and 48 are one-way and operate when forced open by pressure at ports 36 and 38.
Downstream of sleeve valves 46 and 48 and generally above delivery block 30 sheath 44 constricts and terminates with an end 54. In fact, in the preferred embodiment illustrated in FIG. 1 end 54 of sheath 44 forms an outlet valve 56. The elastic material of sheath 44 narrows down to 3Q a thin neck, which is normally closed as the elastic material adheres to itself As a consequence, outlet valve 56 is a one-way, normally closed valve. In other words, outlet valve 56 will only permit the outflow of flowable material 22 when pressure causes the adhering walls at end 54 to open up 3J outlet valve 56. A person with average skill in the art will appreciate that the exact geometry and parameters of outlet valve 56 can vary depending on the way the material of sheath 44 comes together. In general, this type of one-way valve is well known and encompasses three particular types: 4Q a duck bill valve, a slit valve and a flapper valve. Any one of these can be used as outlet valve 56.
Housing 12 has a dispensing port 58 in the form of a circular opening at the point of exit of outlet valve 56. Depending on the application, dispensing port may surround 45 outlet valve 56 and protect end 54 of sheath 44 from contact with external objects. It is also possible for end 54 to protrude beyond the walls of dispensing port 58. This may be desirable if periodic cleaning of outlet valve 56 is anticipated. 50
The general shape of housing 12 is such as to conform to the shape of sheath 44 when delivering flowable material 22. That is because one of the functions of housing 12, besides general protection of the elements of cartridge 10 from the external environmental hazards, is to arrest the expansion of 55 sheath 44. This is necessary to prevent sheath 44 from rupturing and to ensure proper flow delivery characteristics of flowable material 22.
The inner diameter of housing 12 is chosen to be greater than the outer diameter of delivery block 30 by an amount 60 which depends on the desired rate of delivery of flowable material 22 from outlet valve 56. This choice will also take into consideration the viscosity of flowable material 22 and the elasticity and rupture point of sheath 44. Adequate doses of flowable material 22 are possible with expansion in the 65 diameter of sheath 44 of as little as 500 fim. It will be obvious to one skilled in the art that smaller or larger
expansions in the diameter of sheath 44 may be chosen in specific instances.
Additionally, housing 12 also protects sheath 44 from abrasion which could occur if housing 12 were absent as well as when flowable material 22 is being delivered. For this purpose, the internal walls of housing 12 are smooth.
The operation of dispensing cartridge 10 is best explained by FIGS. 2 and 3. In FIG. 2 cartridge 10 is disabled, although flowable material 22 is present in internal channel 34 and branches 40 and 42. In fact, as indicated by arrow A, flowable material 22 has passed through neck 16 and delivery port 24 into internal channel 34 through input port 32. Sleeve valves 46 and 48 at ports 36 and 38 are closed as sheath 44 tightly envelops delivery block 30. The magnified view of sleeve valve 46 shows flowable material 22 wetting sheath 44. Due to insufficient pressure, flowable material 22 is unable to open sleeve valve 46 or 48. Meanwhile, outlet valve 56 remains closed and there is no flowable material 22 downstream of outlet valve 56.
To activate cartridge 10, as shown in FIG. 3, pressure is exerted either on container 14 or on flowable material 22. The former can be accomplished by compressing container 14 by manual or mechanical means including a peristaltic pump and the latter by pumping or other internal means of pressure delivery. Under this pressure both sleeve valves 46 and 48 are forced open by flowable material 22. Sheath 44 expands as flowable material 22 fills the space downstream of sleeve valves 46 and 48. Meanwhile, housing 12 prevents excessive expansion of sheath 44 and its rupture or abrasion.
Next, the pressure of flowable material 22 trapped under sheath 44 opens outlet valve 56. Thus, flowable material 22 is dispensed as indicated by arrow B. As soon as the pressure of flowable material 22 drops below the minimum pressure necessary to keep open sleeve valves 46 and 48, the remaining flowable material 22 will be expelled through outlet valve 56. This will occur due to the pressure exercised by sheath 44 as it contracts back to snugly envelop delivery block 30.
This arrangement of sleeve valves 46 and 48 with outlet valve 56 in tandem is clearly advantageous. There is no back flow of flowable material 22 through either sleeve valve 46 or 48. All flowable material 22 remaining under sheath 44 is expelled through outlet valve 56. Thus, there is no back flow through outlet valve 56 either. As a result, the operation of dispensing cartridge 10 is contamination-safe. No particles 28 of external contaminants 26 can enter through outlet valve 56 and sleeve valves 46 or 48 to end up inside container 22.
The operation of dispensing cartridge 10 is the same during subsequent cycles, since all flowable material 22 trapped downstream of sleeve valves 46 and 48 will always be expelled through outlet valve 56. Dispensing cartridge 10 is thus fit for delivering multiple-doses.
Depending on the application, dispensing cartridge 10 can be mounted on container 14 by the manufacturer or consumer. For example, when flowable material 22 is a paste, medicinal fluid or edible substance intended for the general consumer market, cartridge 10 is conveniently factoryinstalled. Otherwise, the end user can decide when cartridge 10 is required to dispense a particular liquid or fluid.
The construction of dispensing cartridge 10 ensures its operation with materials spanning a wide range of viscosities. Consequently, dispensing cartridge 10 is highly effective and universal. Its contamination-safe operation renders it useful in preserving the purity of virtually any flowable material which is delivered from a container that does not produce an internal vacuum when its contents are expelled.