Plungerless syringe

Abstract: A hollow, molded, disposable, plastic syringe (10) is provided with an air trap chamber (22) in fluid communication with a collapsible container portion (12). An umbilical passage (40) connects the container (12) to the chamber (22). With the air trap chamber (22) extending upwardly from the container portion (12), air is trapped in the chamber (22). The chamber (22) is then removeable by sealing the umbilical passage (40) shut and severing the passage (40) between the seal (43) and the chamber (22). Alternatively, air in the chamber (22) may be retained within the chamber (22) by collapsing of a rear wall (12a) of the container (12) against a forward wall (12b) of the container (12). The syringe (10) is then useable without any air contained in the container (12). The container (12) is shaped to facilitate ejection of an accurate dose without injecting too little or too much of the contained liquid.

Description: BACKGROUND OF THE INVENTION Every day large numbers of syringes are utilized in dispensing fluids. Still the primary device utilized for these injectors is a small cylindrical container or tube, and a plunger piston manually moved within the tube to eject liquid through an outlet at one end of the tube that is connected to a cannula or tubular needle. Some of such syringes are reutilized with proper sterilization in between uses. A variation of the foregoing, which is in widespread use, is to position a sealed cartridge into a syringe-like holder, and a piston rod or actuator carried by the holder depresses a piston in the cartridge to eject fluid out of a needle attached to the cartridge. The tube and the needle are conveniently disposable; however, it is somewhat cumbersome to remove the cartridges and there is a risk of the operator being stuck with the needle during the removal process. The following patents reflect the state of the art of which applicant is aware and are included herewith to discharge applicant's acknowledged duty to disclose relevant prior art. It is stipulated, however, that none of these references teach singly nor render obvious when considered in any conceivable combination the nexus of the instant invention as disclosed in greater detail hereinafter and as particularly claimed. INVENTOR PATENT NO. ISSUE DATE Viviez 470,700 (French) April 7, 1914 Tokita 1,762,430 August 31, 1929 Wirth GB557,400 November 18, 1943 Barrett, et al. 2,744,528 May 8, 1956 Moeck 2,748,770 June 5, 1956 Marchand 2,768,623 October 30, 1956 Elinger 2,911,972 November, 10, 1959 Dunmire 3,089,489 May 14, 1963 Strazdins, et al. 3,335,914 August 15, 1967 Bane 3,340,869 September 12, 1967 Swartz 3,557,788 March 8, 1968 Kline 3,712,295 January 23, 1973 Szabo 3,736,933 June 5, 1973 McAleer, et al. 4,018,222 April 19, 1977 Van Eck 4,130,117 December 19, 1978 Sneider 4,168,032 September 18, 1979 af Ekenstam, et al. 4,282,986 August 11, 1981 Cornett, III 4,411,656 October 25, 1983 Lary 4,548,601 October 22, 1985 Peters 4,753,638 June 28, 1988 The prior art listed above shows the state of the art of which applicant is aware. Each reference is distinguishable from the applicant's invention as claimed. For example US Patent 4,411,656 discloses a compressible plungerless syringe that does not provide a means to trap any air present in the syringe. SUMMARY OF THE INVENTION The present invention satisfies the above-expressed need by providing an inexpensive, blow-molded, collapsible container having a separate chamber which is in communication with the container that traps the air in the chamber. In actuality a blow-fill-seal device such as can be manufactured by Rommelag-Alp machines or perhaps others is contemplated. The chamber is positioned on one side of the container in a location that is generally perpendicular to the direction that the container is squeezed to collapse it. By positioning the syringe with the chamber extending upwardly, the liquid in the chamber will flow by gravity into the container displacing any air in the container into the chamber. Once the air is in the chamber, an umbilical passage between the chamber and the container can be sealed preventing fluid flow therethrough. The umbilical passage is then severable between the point of sealing and the chamber, permanently removing gas from the container regardless of its orientation. The container is provided with an outlet portion that is conveniently attached to a needle. The needle can be attached to the container during its manufacturing process, however, it is preferable that the liquid outlet for the container be sealed by a suitable plug wich is removed and replaced by the needle when the syringe is to be utilized. The container has a rear wall and a forward wall of similar shape and joined together by a cylindrical band. The rear wall has a surface area greater than the area projected by the cylindrical band. The rear wall is deformable and can be pushed toward the forward wall to eject liquid from the container through the outlet portion. When the rear wall is forced through the cylindrical band, the force necessary to continue is decreased until the rear wall impacts the forward wall, at which time the rear wall is stopped and the ejection of liquid ceases. The container is formed of material allowing it to snap somewhat into a position with the rear wall adjacent to the forward wall. This snapping action aids a user in knowing when the proper amount of fluid has been ejected. OBJECTS OF THE INVENTION Accordingly, it is a primary object of the present invention to provide a syringe adjustable to exclude all gas from within, thereby approximating a 100% liquid environment. Viewed from a first vantage point it is an object of this invention to provide a plungerless syringe comprising a hollow, collapsible container made of material which is sufficiently stiff to maintain its shape, but is sufficiently flexible to be manually collapsed by the fingers of the user, said container having an outlet through which liquid in the container is ejected upon collapsing the container; and an air trap in the form of a small chamber which is in fluid communication with said container, said chamber being physically connected to the container in a manner and location such that when the container and the chamber are oriented so that air or other gas in the container is displaced upwardly into the chamber , the air will be trapped in the chamber when the container is collapsed to eject the liquid, wherein said container has a bellows disk shape somewhat like one section of a bellows including a forward wall with said outlet therein, a rear wall and an annular peripheral wall, and wherein said chamber is connected by a passage opening to said peripheral wall, said container being collapsible by pressing said rear wall toward said forward wall. Viewed from a second vantage point it is an object of this invention to provide a dispenser for ejecting liquid housed within said dispenser and excluding gas from said dispenser, comprising a container having a liquid outlet and a gas outlet, said liquid outlet spaced from said gas outlet, said gas outlet communicating with a chamber through communication means to exclude gas from within said container, and said container having a dispensing means capable of ejecting liquid from within. Viewed from a third vantage point it is an object of this invention to provide a plungerless syringe comprising a hollow, collapsible container made of material which is sufficiently stiff to maintain its shape, but is sufficiently flexible to be manually collapsed by fingers of a user, said container having an outlet through which liquid in said container is ejected upon collapsing said container; and a gas trap in the form of a small chamber which is in fluid communication with said container, said chamber being physically connected to said container in a manner and location such that when said container and said chamber are oriented so that gas in said container is displaced into said chamber, the gas will be trapped in said chamber prior to and when said container is collapsed to eject the liquid. Viewed from a fourth vantage point it is an object of this invention to provide a plungerless syringe wherein said container has a bellows disk shape somewhat like one section of a bellows including a forward wall with said outlet therein, a rear wall and an annular peripheral wall, and wherein said chamber is connected by a passage opening to said peripheral wall, said container being collapsible by pressing said rear wall toward said forward wall. Viewed from a fifth vantage point it is an object of this invention to provide a dispenser for ejecting liquid housed within said dispenser while retaining gas residing within said dispenser, comprising a container having a liquid outlet and a gas outlet, said liquid outlet spaced from said gas outlet, said gas outlet communicating with a chamber to store the gas therewithin, said container formed with at least one wall which moves from a first position to a second position, said first position defining a liquid retaining position whereupon the liquid remains stored within said container, and said second position defining a liquid ejected position whereupon the liquid has been expelled from said dispenser and said one wall occludes said gas outlet from said liquid outlet by collapsing said container and covering said gas outlet. Viewed from a sixth vantage point it is an object of this invention to provide a dispenser wherein said communication means includes sealing means for sealing said communication means shut, whereby gas or liquid is prohibited from passing through said communication means when said sealing means is utilized. Viewed from a seventh vantage point it is an object of this invention to provide a dispenser wherein said communication means is an umbilical passage having a hollow interior interfacing with both said container and said chamber on opposite ends thereof, wherein a chamber separation means is provided capable of separating said chamber from fluid communication with said container through severance of said umbilical passage between said sealing means and said chamber. Viewed from an eighth vantage point it is an object of this invention to provide a dispenser wherein said sealing means is a tongue fixedly attached to one side of an interior wall of said umbilical passage spanning the width of said umbilical passage and oriented non-parallel to an axis penetrating said ends of said umbilical passage; and a groove complemental to said tongue and formed to a second side of said interior wall of said umbilical passage opposite said tongue, whereby when compressive force is applied to said umbilical passage said tongue locks into said groove prohibiting fluid or gas from passing therebeyond. Viewed from a ninth vantage point it is an object of this invention to provide a plungerless syringe comprising a hollow, collapsible container made of a material which is sufficiently stiff to maintain its shape but is sufficiently flexible to be manually collapsed by fingers of a user, said container having an outlet through which liquid in said container is ejected upon collapsing said container; and a severable air trap in the form of a small chamber which is in temporary fluid communication with said container through a communication means, said chamber being physically connected to said container in a manner and location such that all air or other gas in said container is displaced into said container; whereby gas is separated from the liquid and prevented from passing through said outlet, wherein said communication means is an umbilical passage having a hollow interior interfacing with both said container and said chamber on opposite ends thereof, wherein said umbilical passage includes sealing means and severance means between said sealing means and said chamber; whereby said umbilical passage can be blocked and said chamber can be removed from said syringe, leaving said container of said syringe without any gas therein. Viewed from a tenth vantage point it is an object of this invention to provide a method for ejecting liquid from a liquid dispenser while preventing gas within the liquid dispenser from being dispensed with the liquid, the steps including: forming the dispenser with a container having a liquid outlet and a chamber communicating with the container by means of a gas outlet spaced from the liquid outlet, orienting a container and associated chamber to allow gas within the container to move into the associated chamber through the gas outlet, sealing the passage to prevent the gas from reentering the container upon reorienting of the container and associated chamber, positioning the dispenser with the liquid outlet outlet to the container located in a region desired for liquid dispensing, and compressing the wall of the container causing the liquid within the container to be expelled through the liquid outlet, wherein severing of the gas outlet occurs between a sealing location and a location of the chamber after said sealing step and before said comprissing step, whereby the chamber and included gas are removed from the dispenser. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view showing the exterior of the syringe of the invention, with the user's fingers shown in phantom lines. Figure 2 is a cross-sectional view of the syringe of figure 1. Figure 3 is a cross-sectional view of the syringe of figure 2 with the outlet closure removed and replaced by a needle. Figure 4 is a cross-sectional view similar to figure 3 but with the container collapsed. Figure 5A is a plan view showing another embodiment of the syringe. Figure 5B is a cut-away plan view showing inner details of the syringe of figure 5A. Figure 6A is a cross-sectional view taken along line 6-6 of figure 5A. Figure 6B is a cross-sectional view taken along line 6-6 of figure 5A, showing an alternative embodiment of the syringe. Figure 7 is a plan view of the syringe of figure 5A with a portion removed. Figure 8A is a plan view of a cap for the syringe. Figure 8B is a plan view of the syringe with the cap superimposed thereon in phantom. Figure 8C is a plan view of the syringe being dispensed. Figure 9A is an isometric view of a cap for the syringe. Figure 9B is an isometric view of the syringe after having dispensed fluid. Figure 10 is a graph expressing force and displacement relationships of the syringe. DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawings wherein like reference numerals represent like parts throughout, reference numeral 10 refers to a plungerless syringe. The syringe 10 includes a container 12, a chamber 22 and an outlet portion 18 spaced from the chamber 22. In essence, the container 12 is a hollow construct having inner and outer surfaces. A forward portion of the container 12 has a central opening 12c which leads into the outlet portion 18 of the syringe 10. The chamber 22 connects to a side of the container 12 through an umbilical passage 40 interposed therebetween. The umbilical passage 40 allows the chamber 22 and the container 12 to be in fluid communication with each other. The outlet portion 18 is connectable to a needle 34, as shown in figures 1 through 4 and figures 8B, 8C and 9B or to a cannula as shown in figure 7 for injection of the liquids contained therein into a patient. More specifically, and referring to figures 1 through 9B, the container 12 is formed from a rear wall 12a, an annulas peripheral wall 12d, a central cylindrical band 12e, and a forward wall 12b. The annulas peripheral wall 12d and forward wall 12b are frusto-conical in shape with ends of lesser diameter opposite each other, and ends of greater diameter facing each other. Each greater diameter end of the annular peripheral wall 12d and forward wall 12b is connected to opposite ends of the cylindrical band 12e. The rear wall 12a encloses the lesser diameter end of the annular peripheral wall 12d. The lesser diameter end of the forward wall 12b remains open creating the central opening 12c. A neck 14 is attached to the forward wall 12b surrounding the central opening 12c and leads toward the outlet portion 18 of the syringe 10. Circumscribing the neck 14 and the outlet portion 18 is a finger engaging portion 16, shown in figures 1 through 4 and figures 8B and 9B. The finger engaging portion 16 allows the user to more efficiently utilize the syringe 10. A cap 17, shown in figures 8A, 8B and 9A, is provided to cover the needle 34 and keep the outlet 18 in a sterile environment. The cap 17 is a cylindrical hollow construct having a flat end wall 17b enclosing one end and a circular opening 17a on an opposite end. The circular opening 17a is sized to snap over the finger engaging portion 16 securing the cap 17 to the syringe 10. The chamber 22 is a substantially spherical hollow construct. A portion of the chamber 22 opens into the umbilical passage 40. The umbilical passage 40 has an inside surface 41 (figures 6A and 6B) which is adjacent to the interior of the container 12 and the chamber 22. Liquids and gases within the container 12 may freely pass along the inside surface 41 of the umbilical passage 40 into the chamber 22 and vice versa. According to a preferred embodiment shown in figure 6B a seal 43 is formed along the inside surface 41 of the umbilical passage 40. The seal 43 is one of a variety of connectors capable of sealing off the container 12 from fluid communication with the chamber 22. One seal 43, shown in figure 6A, involves having smooth adjacent inside surfaces 41 of the umbilical passage 40. These surfaces can be connected by application of a welding device on the exterior of the umbilical passage 40. Another alternative method for connection of the inside surfaces 41 of the umbilical passage, shown in figure 6A, is to apply adhesive material "A" to the adjacent inside surfaces 41 and compressing the umbilical passage 40 to connect the two inside surfaces 41 together forming the seal 43. The seal 43 can also be formed, as shown in figure 6B, through addition of a tongue 46 on one inside surface 41 and a groove 48 adjacent to the tongue 46 on the opposite inside surface 41. The tongue 46 is sized to fit within the groove 48 such that when compressive forces are applied to the outside of the umbilical passage 40 the seal 43 is formed. Before utilization of the syringe 10 the outlet portion 18 is fitted with a removeable closure 20, shown in figures 1 and 2. The closure 20 is removed before use when a needle 34 or cannula 26 may be connected to the outlet portion 18. The needle 34 and cannula 26 are formed of a shape similar to those existing in other similar devices readily available in the art. The needle 34 or cannula 26 are connectable to the outlet portion 18 of the syringe 10 in a manner allowing liquids within the container 12 to be ejected through the needle 34 or cannula 26. A closure 20, formed from a fiber 20a and a gripper 20b, is inserted into the tip 18a to keep the interior of the syringe 10 clean before the needle 34 or cannula 26 is connected to the outlet portion 18 (figures 1 and 2). As shown in figure 7, the cannula 26 can connect into another apparatus for injection of the liquid into the patient. The annular peripheral wall 12d and rear wall 12a are joined together by a linear seam 80, shown in figure 9B, which strategycally passes linearly from one side of the cylindrical band 12e along a diameter to an opposite side of the cylindrical band 12e. Typically, the seam 80 occurs in the molding process. The area projected by the cylindrical band 12e when viewed from the rear is less than the total surface area of the rear wall 12a plus the annular peripheral wall 12d. The container 12 is formed from a material having sufficient flexibility to allow the total surface area of the rear wall 12a and the annular peripheral wall 12d to be compressed so that the total surface area of the rear wall 12a and the annular peripheral wall 12d is less than the cylindrical band 12e, allowing the rear wall 12a to pass through the cylindrical band 12e when a sufficient force F is applied to the rear wall 12a and toward the forward wall 12b. The seam 80 facilitates buckling of the rear wall 12a and the annular peripheral wall 12d to allow the rear wall 12a to pass through the cylindrical band 12e and continue forward until the annular peripheral wall 12d comes into contact with the forward wall 12b and the rear wall 12a rests over the central opening 12c, as shown in figures 4, 8C and 9B. Referring now to figure 10, the container 12 including the seam 80 is designed to require that an increasing amount of force (from the initial force required, F i ) be required to deflect the rear wall 12a more greatly (from the point of no deflection, D i ) toward the central opening 12c. This increasing force requirement abruptly changes (when the applied force equals F m , the maximum force required for injection) after the rear wall 12a passes through the cylindrical band 12e as the rear wall 12a and annular peripheral wall 12d are allowed to expand to their original area on the side of the cylindrical band 12e closer to the central opening 12c. This drop in required force is exhibited until the annular peripheral wall 12d collapses against the forward wall 12b (when rear wall 12a displacement equals D f , the final displacement of the rear wall 12a). The force required to further displace the rear wall 12a then increases sharply because the rear wall 12a is restricted from passing farther into the central opening 12c due to its attachment to the annular peripheral wall 12d which is abutting against forward wall 12b. The characteristics of this force versus displacement curve of figure 10 show that the syringe 10 allows a user to provide a dose to a patient in a fairly predictable amount. An initial force F i is enough to prohibit the user from accidentally discharging some of the liquid within the container 12 by inadvertently pushing the rear wall 12a slightly. Once the maximum force required F m is reached, at the point where the rear wall 12a is substantially coplanar with a plane surrounded by the cylindrical band 12e, the force required then drops off rapidly allowing the user to apply only a small force to finish ejecting the remaining liquid. Once the annular peripheral wall 12d impacts the forward wall 12b the position D f is reached at which point a greater force is required to further depress the rear wall 12a. The user is then signaled by the extra force required for further displacement that the total amount of liquid has been ejected and no further force need be applied to the rear wall 12a of the container 12. In use and operation, the syringe 10 is to be evacuated of any air contained within the container 12 through the following preferred process. First, the container 12 is oriented with the chamber 22 above the container 12 in elevation. Any air within the container 12 then floats to the top as gravity draws liquid within the chamber 22 and container 12 downward. Vibration (tapping) may assist this stage. Once all of the gas has passed upward through the umbilical passage 40 into the chamber 22, the umbilical passage 40 may then be sealed using the seal 43. The chamber 22 may then be severed from the container 12 by either cutting the umbilical passage 40 between the seal 43 and the chamber 22 with a cutting tool or by tearing the umbilical passage 40 along a score line S formed around the umbilical passage 40 providing a guide for manual tearing away of the chamber 22. The device also lends itself to air (or gas) sequestration at the site of fabrication and fluid introduction using an automated process. Once the chamber 22 has been removed from the container 12, as shown in figures 7 through 9, the syringe 10 is ready for use on a patient without risk that air will be injected therefrom. In an alternative embodiment, air may be prohibited from exiting through the outlet portion 18 in the following manner. First, the container 12 is oriented with the chamber 22 above the container 12 in elevation. Any air within the container 12 then floats to the top as gravity draws liquid within the chamber 22 and container 12 downward. Once all of the gas has passed upward through the umbilical passage 40 into the chamber 22, the syringe 10 is prepared for use. With the chamber 22 above the container 12, the user depresses the rear wall 12a. As the rear wall 12a moves forward liquid is ejected out of the outlet portion 18. When the rear wall 12a contacts the neck 14 surrounding the opening 12c all air within the chamber 22 is sealed off from entering the outlet portion 18 by contact between the annular peripheral wall 12d and the forward wall 12b. Moreover, having thus described the invention, it should be apparent that numerous structural modifications and adaptations may be resorted to without departing from the scope of the instant invention as set forth hereinabove and as described hereinbelow by the claims.

Claims: A plungerless syringe (10) for ejecting liquid housed within said syringe (10) comprising a container (12) having a liquid outlet (18) and said container (12) having a dispensing means capable of ejecting liquid from within characterized in that the container comprises a gas outlet, said liquid outlet (18) being spaced from said gas outlet, said gas outlet communicating with a chamber (22) through communication means to exclude gas from within said container (12). A plungerless syringe according to claim 1 wherein the container (12) is a hollow, collapsible container (12) made of material which is sufficiently stiff to maintain its shape, but is sufficiently flexible to be manually collapsed by fingers of a user. A plungerless syringe according to claim 2 wherein the chamber (22) is physically connected to said container (12) in a manner and location such that when said container (12) and said chamber (22) are oriented so that gas in said container (12) is displaced upwardly into said chamber (22), the gas will be trapped in said container (22) prior to and when said container (12) is collapsed to eject the liquid. A plungerless syringe according to claim 3 wherein said container (12) has a bellows disk shape somewhat like one section of a bellows including a forward wall (12b) with said outlet (18) therein, a rear wall (12a) and an annular peripheral wall (12d), and wherein said chamber (22) is connected by a passage (40) opening to said peripheral wall (12d), said container (12) being collapsible by pressing said rear wall (12a) toward said forward wall (12b). A plungerless syringe according to any preceding claims wherein the communication means includes sealing means (43) to permanently exclude gas from within said container (12). A plungerless syringe according to claim 5 wherein the communication means is an umbilical passage (40) having a hollow interior interfacing with both said container (12) and said chamber (22) on opposite ends thereof, and wherein a chamber separation means is provided capable of separating said chamber (22) from fluid communication with said container (12) through severance of said umbilical passage (40) between said sealing means (43) and said chamber (22). A plungerless syringe according to claim 6 wherein said sealing means (43) is a tongue (46) fixedly attached to one side of an interior wall (41) of said umbilical passage (40) spanning the width of said umbilical passage (40); and oriented non-parallel to an axis penetrating said ends of said umbilical passage (40); and a groove (48) complemental to said tongue (46) and formed to a second side of said interior wall (41) of said umbilical passage (40) opposite said tongue (46), whereby when compressive force is applied to said umbilical passage (40) said tongue (46) locks into said groove (48) prohibiting fluid or gas from passing therebeyond. A plungerless syringe according to claims 1 or 2 wherein said container (12) is formed with at least one wall which moves from a first position to a second position, said first position defining a liquid retaining position whereupon the liquid remains stored within said container (12), and said second position defining a liquid ejected position whereupon the liquid has been expelled from said syringe (10) and said one wall occludes said gas outlet (18) by collapsing said container (12) and covering said gas outlet. A plungerless syringe according to claim 5 wherein the sealing means (43) involves having smooth adjacent inside surfaces (41) of the umbilical passage (40) which can be connected by application of a welding device on the exterior of the umbilical passage (40) A plungerless syringe according to any preceding claims wherein the gas is air. A method for ejecting liquid from a syringe (10) while preventing gas within the syringe (10) from being dispensed with the liquid, said method being not a method for treatment of the human body or animal body, the steps of the method including forming the syringe (10) with a container (12) having a liquid outlet (18) and a chamber (22) communicating with the container (12) by means of a gas outlet spaced from the liquid outlet (18), orienting the container (12) and associated chamber (22) to allow gas within the container (12) to move into the associated chamber (22) through the gas outlet, sealing the passage to prevent the gas from reentering the container (12) upon reorienting of the container (12) and associated chamber (22), positioning the syringe (10) with the liquid outlet (18) to the container (12) upon reorienting of the container (12) and the associated chamber (22), positioning the syringe (10) with the liquid outlet (18) to the container (12) located in a region desired for liquid dispensing, and compressing the wall of the container (12) causing the liquid within the container (12) to be expelled through the liquid outlet (18); and wherein severing of the gas outlet occurs between a sealing location and a chamber (22) location after said sealing step and before said compressing step.

Inventors: FARRIS BARRY, FARRIS, BARRY
Applicants: FARRIS BARRY, FARRIS, BARRY
Application year: 1991
Main classification: A61M5
IPC codes: A61M5