Patent Publication Number: US-2005119609-A1

Title: Syringe mixer and syringe apparatus incorporating the mixer

Description:
BACKGROUND OF THE INVENTION  
      1. The Field of the Invention  
      This invention is in the field of methods and devices for mixing and dispensing compositions. More particularly, this application is directed to methods and devices for mixing and dispensing multi-part medical and dental compositions.  
      2. The Relevant Technology  
      Couplers have been employed in the art in order to couple one syringe in fluid communication with another syringe. Such couplers are typically configured to be positioned between the syringes by coupling one portion of the coupler to one syringe and another portion of the coupler to another syringe. Typical couplers have a passageway therethrough in order to enable material in one syringe to pass through the passageway of the coupler to the opposing syringe. After coupling the coupler between opposing syringes, material from one syringe may be delivered through the coupler into another syringe.  
      A variety of different uses for such so-called “syringe-to-syringe couplers” are available. For example, syringe-to-syringe couplers may be useful for connecting a large reservoir syringe to the small dose syringe so that the material stored in the large reservoir syringe may be transferred to a small dose syringe. Syringe-to-syringe couplers may also be used for back-filling a syringe or for combining materials in different syringes to form a mixture.  
      First and second syringes may also be coupled directly together without the use of a coupler therebetween in order to combine materials disposed within the syringes. The plungers of the syringes are alternatively compressed or actuated in cycles until the materials within the syringes mix.  
      There are many advantages to typical syringe-to-syringe mixing applications, both with respect to applications involving syringes which directly couple in order to combine material and with respect to syringes which couple through the use of a coupler. However, each of such typical syringe-to-syringe mixing applications feature a single, linear pathway which extends from one syringe to another or from one end of a coupler to an opposing end of the coupler.  
      Consequently, material in the distal tip portion of a first syringe is delivered in a substantially linear manner through the linear pathway to the distal tip portion of a second syringe. If the plunger of the second syringe is then pressed, substantially the same material delivered to the tip of the second syringe is delivered back along the same linear pathway in an opposite direction. As a result, substantially the same material originally delivered from the distal tip of the first syringe is returned back to the distal tip of the first syringe.  
      Thus, material located remotely from the tips can remain in such a remote position and fail to mix. Instead, substantially the same material is pushed back and forth along the linear pathway between the tips of the syringes. Overall, this phenomenon can result in inadequate mixing of the components from one syringe to another or can require long mixing times in order to mix the components.  
      In addition, existing couplers are often relatively complex and cumbersome. It would be an improvement to provide a simpler, but effective device for mixing the contents of coupled syringes.  
     BRIEF SUMMARY OF THE PREFERRED EMBODIMENTS  
      In a syringe system for mixing a two-component composition, the present invention relates to a mixer for enabling mixing of the two components. The mixer is configured to be held at least partially within the tip of one of the syringes, where the syringes may be coupled together. The material held in a first syringe is introduced into a second syringe and then the mixture is repeatedly transferred back and forth between the two syringes. The mixer comprises: (i) a main body having a first surface, a second surface, a first end, and a second end; and (ii) a first valve flap and a second valve flap.  
      The first surface of the main body partially defines a first channel when held at least partially within the tip of a syringe. The first channel extends from the second end of the main body to the first end of the main body. The second surface of the main body partially defines a second channel when held at least partially within the tip of a syringe. The second channel extends from the first end of the main body to the second end of the main body.  
      In use, the mixer is held at least partially within the tip of a first syringe, which is coupled to a second syringe. The first and second syringes are coupled tip to tip. When mixing materials from the two syringes, a first flow path flows from the second syringe through the first channel to the first syringe. A second flow path flows from the first syringe through the second channel to the second syringe. Each channel includes a primary opening and a secondary opening. Material in each flow path enters the respective channel at the primary opening, exiting at the secondary opening.  
      In order to selectively open and close the first and second channels, a valve is located at the secondary opening of each channel. Each valve includes a valve seat and a valve flap. In one embodiment, the first valve seat is an inside surface of the barrel of the first syringe, and the second valve seat is an end surface of the tip of the first syringe. The first and second valve flaps extend outwardly from the main body, and are located at the first and second ends of the main body, respectively. Each valve flap may be a cantilevered flexible zone of the main body.  
      The first cantilevered flexible end can be configured to selectively close the secondary opening of the first channel when the end is positioned against the inside surface of the barrel of the first syringe. The second cantilevered flexible end can be configured to selectively close the secondary opening of the second channel when the end is positioned against the end surface of the tip of the first syringe.  
      In order to mix material in different syringes, the practitioner can deliver material back and forth between the syringes until the material is adequately mixed. Because of the configuration of the first and second channels, a substantially circular, asymmetric, non-linear flow pattern can be achieved when material is alternately delivered from a first syringe to a second syringe and vice versa. This allows convenient and efficient mixing of a first material in the first syringe and a second material in the second syringe. This is particularly useful for two-part type dental and medical compositions, such as epoxies, but is also useful in a variety of different applications in which mixing is desired.  
      In light of the bidirectional nature of the first and second channels, the material in the first syringe flows in a substantially different pathway than material flowing from the second syringe, and vice versa, creating the substantially circular flow pattern. Material expressed from each channel preferably exits outwardly into a side portion of a given syringe. This assists in circulating material from substantially different portions of the first and second syringes.  
      Also because of the side or outward exiting nature of the material, the flow path of material is asymmetric and turbulent. The asymmetric, turbulent flow enhances the mixing of the material. Since the flow pattern is asymmetric and substantially circular, the material is mixed in a quicker and more efficient manner.  
      In one embodiment, the mixer is substantially nonmovably affixed within the tip of a male syringe. According to one embodiment, the mixer may be integrally formed with the male syringe.  
      The mixer is configured to be held at least partially within the tip of one of the syringes at the juncture between the two syringes when the syringes are locked end to end directly to each other. A two syringe mixing apparatus of the present invention may thus comprise a first syringe, a second syringe, and a mixer configured to be held at least partially within the tip of the first syringe.  
      These and other advantages and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      To further clarify the above and other advantages and features of the present invention, a more particular description of the invention will be rendered by references to specific embodiments thereof, which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:  
       FIG. 1A  is a perspective view of a mixer of the present invention;  
       FIG. 1B  is a cross sectional view of a mixer of  FIG. 1A  held within the tip of a first syringe and the first syringe coupled to a second syringe;  
       FIG. 2  is an alternative cross sectional view of the mixer, first syringe, and second syringe of  FIG. 1B ;  
       FIG. 3  is a cross-sectional view of a barrel of a first syringe;  
       FIG. 4  is a cross-sectional view of a barrel of a second syringe;  
       FIG. 5A  is a cross sectional view of a system of the present invention comprising the mixer of  FIG. 1A  and the syringe barrels of  FIGS. 3 and 4 . A material flows through a first flow path, while a second flow path is closed;  
       FIG. 5B  is a view as in  FIG. 5A  in which the material flows through a second flow path while the first flow path is closed.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      I. Introduction  
      As used herein, the term “syringe” and “syringes” includes syringes and other delivery means for delivering material, including, but not limited to, pumps, reservoirs, squeeze bottles, fluid bags, pressurized tanks, and other containers.  
      With reference now to  FIGS. 1A, 1B  and  2 , an example of a mixer  100  of the present invention is shown. Mixer  100  is configured for enabling a material to be transferred from a first syringe for delivering material to a second syringe for delivering material and for enabling another material to be transferred from the second syringe to the first syringe.  
      II. An Exemplary Mixer  
      Mixer  100  has (i) a main body  102  having a first end  104 , a second end  106 , a first surface  108 , and a second surface  110 ; and (ii) first and second valve flaps  134  and  138 . When the mixer  100  is held at least partially within the tip of a syringe, the first surface  108  partially defines a first channel  112 , while second surface  110  partially defines a second channel  114 . First channel  112  extends from first end  104  of the main body  102  to second end  106  of main body  102 . Second channel  114  extends from second end  106  of main body  102  to first end  104  of main body  102 . First and second channels  112  and  114  are both closed in  FIG. 2 .  
      A. Main Body  
      In the mixer embodiment illustrated in  FIGS. 1A-5B , the main body includes first and second surfaces  108  and  110  that partially define first and second channels  112  and  114  through the tip of first syringe  116 . The mixer  100  may be integrally formed with the first syringe  116 , or may be separately inserted so as to be frictionally held in place.  
      First channel  112  is defined by a first surface  108  of main body  102  and a first portion of interior surface  120  of the tip of the male first syringe  116 . First channel  112  defines a first flow path  122 . Also in this embodiment, second channel  114  is defined by an opposing second surface  110  of main body  102  and a second portion of interior surface  120  of the tip of the male first syringe  116 . Second channel  114  defines a second flow path  124 .  
      First channel  112  has a primary opening  126  at first end  104  of main body  102  and a secondary opening  128  (shown as being closed in  FIG. 2 ) at second end  106  of main body  102 . Second channel  114  has a primary opening  130  at second end  106  of main body  102  and a secondary opening  132  (shown as being closed in  FIG. 2 ) at first end  104  of main body  102 .  
      B. Valve Flaps  
      Mixer  100  includes a first valve flap  134  which operates in conjunction with first valve seat  136  to selectively close secondary opening  128  of first channel  112 . A second valve flap  138  operates in conjunction with second valve seat  140  to selectively close secondary opening  132  of second channel  114 . Valve seat  136  may comprise an interior surface of the barrel of first syringe  116 , while valve seat  140  may comprise an end surface of the tip of first syringe  116 .  
      Valve flap  134  has an exterior surface  142  and an interior surface  144 . Valve flap  134  moves away from valve seat  136  when material is delivered from a first syringe within first channel  112  along first flow path  122  and against interior surface  144  of valve flap  134 . Valve flap  134  thereby opens secondary opening  128  of first channel  112 .  
      Valve flap  134  seals against valve seat  136  when material is delivered against an exterior surface  142  of valve flap  134 , i.e., when material is delivered against exterior surface  142  of valve flap  134  from a second syringe. Valve flap  134  thereby closes secondary opening  128 . Valve flap  134  preferably extends outwardly from main body  102 , and is located at first end  104 . As illustrated, valve flap  134  may be a cantilevered flexible zone of main body  102  that extends outwardly at about 90° (when in the closed configuration) relative to the central portion of main body  102 .  
      Mixer  100  also includes a valve flap  138  which operates in conjunction with valve seat  140  to selectively close secondary opening  132  of second channel  114 . In the illustrated embodiment, valve seat  140  comprises an end surface of the tip of first syringe  116 .  
      Valve flap  138  has an exterior surface  146  and an interior surface  148 . Valve flap  138  moves away from valve seat  140  when material is delivered from first syringe  116  within second channel  114  along second flow path  124  and against interior surface  148  of valve flap  138 . Valve flap  138  thereby opens secondary opening  132  of second channel  114 .  
      Valve flap  138  seals against valve seat  140  when material is delivered against an exterior surface  146  of valve flap  138 , i.e., when material is delivered against exterior surface  146  of valve flap  138  from second syringe  118 . Valve flap  138  thereby closes secondary opening  132 . Valve flap  138  extends outwardly from main body  102 , and is located at second end  106 . As illustrated, valve flap  138  may be a cantilevered flexible zone of main body  102  that extends outwardly at about 90° (when in the closed configuration) relative to the central portion of main body  102 . As in the illustrated embodiment, the valve flaps  134  and  138  may be integrally formed with the main body  102  as a single piece.  
      According to one embodiment, the mixer  100  also includes flanges  150  and  152 . Flanges  150  and  152  extend from opposing sides of the central portion of main body  102  so as to hold mixer  100  within the tip of the male first syringe  116 .  
      C. Materials  
      Mixer  100  may be comprised of a variety of different materials, although a material is preferred which is flexible enough that valve flaps  134 ,  138  can selectively open when pressure is applied on the interior surface thereof, yet close when pressure is applied on the exterior surfaces thereof. Examples of such materials which may be suitable in the present invention include polyethylene, polypropylene, neoprene, Santoprene, an olefin, such as J-VON, or another thermoplastic elastomer. The materials used in the mixer are preferably injection-molded. However, a variety of different materials and manufacturing methods can be employed, such as thermoset materials.  
      Materials such as polyethylene and polypropylene may be preferred where the materials to be mixed have a relatively low or moderate viscosity. When mixing higher viscosity materials, a harder material, for example acetal, having a durometer hardness of about 70, may be preferable. It is to be understood that the material chosen may be relatively flexible or more rigid, depending on the intended use.  
      III. An Exemplary System and Method of Use  
      With reference now to  FIGS. 3-5B , an example of a system of the present invention comprises (i) a first syringe  116  ( FIG. 3 ); (ii) a second syringe  118  ( FIG. 4 ); and (iii) mixer  100  ( FIG. 1A ) for enabling a practitioner to mix two components when first syringe  116  is coupled to second syringe  118 .  
      In the embodiment of  FIG. 3 , first syringe  116  comprises a syringe barrel  154  and a syringe plunger (not shown in  FIG. 3 ). Syringe barrel  154  has (i) a hollow main body  156  having a proximal end  158  and a distal end  160 ; and (ii) a hollow tip  162  coupled to and in fluid communication with main body  156 .  
      Tip  162  has an interior surface  164 , an exterior surface  166 , an internal circular shoulder  168 , and female grooves  170  intended to mate with male threads of second syringe  118 . As can be seen in  FIG. 5A , upon extending first end  104  of mixer  100  past circular shoulder  168 , first end  104  secures behind shoulder  168  and interior surface  164  of tip  162  frictionally engages flanges  150 ,  152  of mixer  100 . In this manner, mixer  100  is held within the tip  162  of barrel  154 .  
      In the embodiment of  FIG. 4 , second syringe  118  comprises a syringe barrel  172  and a syringe plunger (not shown in  FIG. 4 ). Syringe barrel  172  has (i) a hollow main body  174  having a proximal end  176  and a distal end  178 ; and (ii) a hollow tip  180  coupled to and in fluid communication with main body  174 .  
      Tip  180  has an interior surface  182 , an exterior surface  184 , an internal circular shoulder  186 , and male threads  188  extending from exterior surface  184 . Male threads  188  are configured to selectively mate directly with female grooves  170  of first syringe  116 .  
      As can be seen in  FIG. 5A , upon selectively coupling tip  180  of second syringe  118  to tip  162  of first syringe  116  after mixing apparatus  100  is placed within first syringe tip  162 , the mixing apparatus  100  is frictionally held in place by flanges  150  and  152  contacting the interior surface  164  of first syringe tip  162 . First barrel  154  and second barrel  172  are thus in fluid communication. Upon placing material and plungers within respective barrels  154  and  172 , the material can be readily mixed by pressing against alternating plungers.  
      With continued reference now to  FIG. 5A , first flow path  122  is shown. In operation, material delivered from second syringe  118  enters first channel  112  and travels along first flow path  122 , exiting at secondary opening  128 . As material is delivered along path  122 , valve flap  134  is opened and unseated from valve seat  136 . Flow path  122  extends out of secondary opening  128  past valve flap  134  in an outward manner, i.e., toward the wall of barrel  154 . In the embodiment of  FIG. 5A , material flows from second syringe  118 . Thus, material from second syringe  118  pushes against exterior surface  146 , causing second valve flap  138  to press against second valve seat  140 , sealing secondary opening  132  of second channel  114 .  
      With reference now to  FIG. 5B , second flow path  124  is shown. In operation, material delivered from first syringe  116  enters second channel  114  and travels along second flow path  124 , exiting at secondary opening  132 . As material is delivered along path  124 , valve flap  138  is opened and unseated from valve seat  140 . Flow path  124  extends out of secondary opening  132  past valve flap  138  in an outward manner, i.e., toward the wall of barrel  172 . In the embodiment of  FIG. 5B , material flows from first syringe  116 . Thus, material from first syringe  116  pushes against exterior surface  142 , causing first valve flap  134  to press against first valve seat  136 , sealing secondary opening  128  of first channel  112 .  
      A schematic representation of the first and second flow paths  122  and  124  achieved when plungers in first and second barrels  154  and  172  are alternately compressed or actuated is shown in  FIGS. 5A and 5B . Material flowing across mixer  100  is expressed through secondary openings  128  and  132  in an outward direction, i.e., toward the walls of respective barrels  154  and  172 , aiding in circulation of material. Consequently, the exit pattern of path  122  is substantially remote from the entrance pattern of path  124 , and vice versa, thereby providing for a circulating, mixing motion. Mixer  100  thus enables the circulation of material between syringe barrels in a substantially circular flow pattern, as opposed to movement of material back and forth between tips.  
      A variety of different materials may be mixed through the use of mixer  100 , including liquids and powders and other compositions, such as A/B type compositions used in medicine and dentistry. Examples of A-B type materials which may be mixed with mixer  100  include epoxies, luting agents, powder-liquid combinations, powder-powder combinations, liquid-liquid combinations, two-part bleaching materials, and a variety of other materials known in the art or yet to be produced.  
      The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.