fig1 of the drawings shows an injection device 10 for injecting a solution which is generated by blending of a liquid solvent 14 and a solid solute 16 which have been loaded into the injection device 10 . the injection device 10 is disposed to hold the liquid solvent 14 and the solid solute 16 apart until the moment of injection , and to intermix or blend within the injection device 10 the liquid solvent 14 and the solid solute 16 , thereby generating the solution which is to be injected . the injection device 10 may comprise a barrel 12 which is intended to contain the liquid solvent 14 and the solid solute 16 . referring also to fig2 , the barrel 12 may comprise a lateral wall 18 having an interior surface 20 , a plunger end 22 , and an opposed delivery end 24 . a chamber 26 is defined within the interior surface 20 between the plunger end 22 and the delivery end 24 . a hollow needle 28 may be coupled to the barrel 12 at the delivery end 24 of the barrel 12 . the hollow needle 28 may have a pointed discharge end 30 adapted for example to penetrate the skin of a person for injecting medicaments , an opposed entry end 32 , and a bore 34 extending from the entry end 30 to the pointed discharge end 30 . the entry end 32 of the hollow needle 28 may be embedded in the constituent material of the delivery end 24 of the barrel 12 or otherwise sturdily coupled thereto . a fluid pathway 36 formed in the barrel 12 communicates between the chamber 26 and the bore 34 of the hollow needle 28 , thereby establishing a continuous path for liquids to traverse when being injected , although the actual path available to solution being injected is longer and less direct than suggested by fig2 . returning to fig1 , the chamber 26 contains components which for better understanding have been shown isolated from the barrel 12 in fig3 and 4 . as seen in fig1 , these components include a plunger 38 , which may incorporate an o - ring 40 for preventing escape of pressurized solution past the plunger 38 . the plunger 38 may be slideably engaged with the interior surface 20 of the barrel at the plunger end 22 of the barrel 12 . a barrier which may be of aluminum foil 41 may be disposed within the chamber 26 , being interposed between the plunger 38 and two additional components which may combine to establish a flow path for solution which is more intricate and effective in promoting blending of the solid solute 16 in the liquid solvent 14 than would be the case of the open chamber 26 as depicted in fig2 . one of these members is a flow path member 42 , the purpose of which is to establish a flow path along which the solution generated by blending of the liquid solvent 14 and the solid solute 16 may flow responsively to urging of the plunger 38 towards the hollow needle 28 . the plunger 38 may be generally conventional in construction and purpose , being provided to transfer manual force to liquids being injected by the injection device 10 . the flow path member 42 may be disposed between , on one hand , the liquid solvent 14 and the solid solute 16 , and on the other hand , the hollow needle 28 . the nature of the flow path member 42 is best described with reference to fig5 . the flow path member 42 may comprise an axially expansible , flexible helical member . when this flexible helical member is viewed in cross section , it may display a generally rectangular perimeter 46 which further comprises a forward axial surface 48 and a rear axial surface 50 . the forward axial surface 48 may bear a groove 52 . the flow path member 42 may be formed from a somewhat elastic member , such as a synthetic resin , so that it can be manually grasped and axially expanded , as depicted in fig5 . in the expanded condition , the flow path member may resemble a coil spring ( not shown ). it is not the expanded condition that is central to the invention , but rather the compressed condition seen in fig1 and 3 . referring particularly to fig3 , the flow path member 42 is compressible to form a cylindrical member or configuration , having a continuous cylindrical outer surface 54 , a forward axial surface 56 , and a rear axial surface 58 . in the compressed configuration of fig1 and 3 , the groove assumes a helical configuration which tracks or mirrors the helical configuration of the flow path member 42 . however , compression of the flow path member 42 causes abutment of the forward axial surface 56 and the rear axial surface 58 of adjacent turns of the helix formed by the flow path member 42 . this closes access of the groove 52 to the exterior of the flow path member 42 along the continuous cylindrical outer surface 54 . the groove 52 , which now defines a helical flow path by virtue of being closed to the exterior of the flow path member 42 , is exposed to the exterior of the cylindrical flow path member 42 only at the forward axial surface 56 and at the rear axial surface 58 of the cylindrical flow path member 42 when the latter is compressed . in the compressed state , the flow path member 42 may form an annular member having the continuous cylindrical outer surface 54 , and also a cylindrical inner surface 60 . the cylindrical inner surface 60 may be said to define a void at the center of the compressed flow path member 42 between the forward axial surface 56 and the rear axial surface 58 . a core member 44 may be provided which cooperates closely with the compressed flow path member 42 . the core member 44 may reinforce the flow path member 42 to better maintain the annular configuration shown in fig3 . the core member 44 may also contribute to the flow path available to the solution , as will be described hereinafter . again referring to fig1 , the barrier provided by the aluminum foil 41 separates the liquid solvent 14 from the solid solute 16 until the time of injection . at that time , manual pressure exerted on the plunger 38 from the right thereof in the depiction of fig1 in the direction of the hollow needle 28 will act to open the barrier so as to enable fluid communication between the liquid solvent 14 and the solid solute 16 , and subsequent mixing or blending of the two to generate the solution . blending and propulsion of the liquid solvent 14 towards the hollow needle 28 , and of the solution which the liquid solvent 14 becomes as it negotiates the flow path established by the groove 52 are both consequences of the manual pressure imposed on the plunger 38 . the solution is constrained against escape from the flow path by close fit of the components of the injection device 10 , and by o - rings such as the o - ring 40 of the plunger 38 and an o - ring 62 which may be placed on the core member 44 . while sealing arising from any of the various o - rings featured herein contributes to preventing loss of solution such as past the plunger 38 , sealing especially constrains the solution against bypassing the flow path member 42 , thus assuring effective blending . the barrier separating the liquid solvent 14 from the solid solute 16 may be opened or breached in any of several ways . notably , the barrier may be a frangible barrier which is ruptured , it may be deflected to open or expose a flow path , or it may be deformed to open or expose a flow path . the first option , that of breaking a frangible barrier , is illustrated in fig1 and 6 . fig1 shows an initial position of the plunger 38 , wherein injection has not yet been initiated . injection and blending are initiated by urging the plunger 38 to the left , as depicted in fig1 . in fig6 , the plunger 38 has been moved such that it has ruptured the aluminum foil 41 and has propelled the liquid solvent 14 past the solid solute 16 , through the flow path member 42 , through the fluid pathway 36 ( see fig2 ), and out through the bore 34 of the hollow needle 28 . the direction of flow is indicated by an arrow 66 in fig6 . the aluminum foil 41 has been ruptured by a pointed finger 64 , best seen in fig4 , and is not shown in fig6 . the barrier provided by the aluminum foil 41 may in other forms be opened so as to enable fluid communication between the liquid solvent 14 and the solid solute 16 may comprises a finger , such as the pointed finger 66 , which is disposed to establish actuating contact with the barrier in ways other than by rupturing the barrier . whereas in fig1 the barrier is frangible and the finger 66 pierces the barrier to open the barrier , a finger may displace a valve to open the barrier . an exemplary valve assembly 70 which may be finger operated is seen in fig7 . the valve assembly 70 may comprise a housing 72 bearing a valve flow path 74 . the valve flow path 74 may comprise an initial section 76 , a second section 78 , and a final section 80 . a valve 82 may take the form of a sphere , such as a plastic ball 82 . the plastic ball 82 may initially occupy the initial section 76 , being retained against loss by an o - ring 84 . turning now to fig8 , there is shown an injection device 110 which is generally the structural and functional equivalent of the injection device 10 of fig1 , apart from the nature of the barrier . the valve assembly 70 described with reference to fig7 serves as the barrier in the injection device 110 . the injection device 110 may have a barrel 112 , a hollow needle 128 , a flow path member 142 , and a core member 144 , all of which may be the structural and functional respective equivalents of the barrel 12 , the hollow needle 28 , the flow path member 142 , and the core member 144 . a plunger 138 may have a blunt ended finger 164 , but in other ways may be the structural and functional equivalent of the plunger 38 . a liquid solvent 14 and a solid solute 16 are stored within and on opposing sides of the barrel 112 . in fig8 , the finger 164 is approaching the point of contact with the plastic ball 82 . as the finger 164 continues to advance to the left , as seen in fig9 , the liquid solvent 14 is propelled through the valve flow path 74 into blending contact with the solid solute 16 . the liquid solvent 14 and the solid solute 16 are then propelled through the flow path member 142 , where dissolution is furthered prior to discharge of solution through the hollow needle 128 . in summary , the barrier comprises the valve assembly 70 the plastic ball 82 of which is displaced non - axially by the finger 164 to open the barrier . fig1 and 11 illustrate a valve assembly 270 wherein the valve 282 is axially shiftable to expose a flow path 274 when the valve 282 is axially shifted to open the barrier provided by the valve assembly 270 . the valve assembly 270 may be substituted in an injection device according to at least one aspect of the invention , such as the injection device 110 . in this example , the valve assembly 70 may be omitted , with the valve assembly 270 installed thereinstead . it should be noted that in the injection devices 10 and 110 , and also with reference to the valve 270 , the barrier provided respectively by the aluminum foil 41 , the valve 70 , or the valve 270 may be operated by fluid pressure developed by the associated plungers 38 or 138 when the latter are moved as described priorly with respect to mechanical action . fig1 and 13 show a further type of barrier . in fig1 , a barrier is established by a flexible rubbery member 370 , which may be arranged to close the internal passage 374 if the rubbery member 370 is not acted on by an external element . such an external element may be provided by a suitably configured finger 364 which may be part of an associated plunger ( not shown in its entirety ), such as the plunger 38 or 138 . the finger 364 may have structure such as a wing 365 for spreading open the rubbery member 370 to open the barrier established thereby to fluid communication enabling a liquid solvent such as the liquid solvent 14 to pass and blend with a solid solute such as the solid solute 16 , as occurs with the injection devices 10 and 110 . fig1 shows a flow path member 142 which performs the same function as the flow path member 42 of fig5 . the difference is that the flow path member 142 has no groove such as the groove 52 of fig5 . the flow path member 142 is nonetheless operable because pressure imposed on fluid of the solution being injected slightly spreads apart adjacent coils of the flow path member , thereby establishing a flow path between adjacent coils which corresponds to the flow path which occupies the groove 52 of fig5 . the nature of the flow path member 42 is best described with reference to fig5 . the flow path member 42 may comprise an axially expansible , flexible helical member . when this flexible helical member is viewed in cross section , it may display a generally rectangular perimeter 46 which further comprises a forward axial surface 48 and a rear axial surface 50 . the forward axial surface 48 may bear a groove 52 . the flow path member 42 may be formed from a somewhat elastic member , such as a synthetic resin , so that it can be manually grasped and axially expanded , as depicted in fig5 . in the expanded condition , the flow path member may resemble a coil spring ( not shown ). it is not the expanded condition that is central to the invention , but rather the compressed condition seen in fig1 and 3 . referring particularly to fig3 , the flow path member 42 is compressible to form a cylindrical member or configuration , having a continuous cylindrical outer surface 54 , a forward axial surface 56 , and a rear axial surface 58 . in the compressed configuration of fig1 and 3 , the groove assumes a helical configuration which tracks or mirrors the helical configuration of the flow path member 42 . however , compression of the flow path member 42 causes abutment of the forward axial surface 56 and the rear axial surface 58 of adjacent turns of the helix formed by the flow path member 42 . this closes access of the groove 52 to the exterior of the flow path member 42 along the continuous cylindrical outer surface 54 . the groove 52 , which now defines a helical flow path by virtue of being closed to the exterior of the flow path member 42 , is exposed to the exterior of the cylindrical flow path member 42 only at the forward axial surface 56 and at the rear axial surface 58 of the cylindrical flow path member 42 when the latter is compressed . in the compressed state , the flow path member 42 may form an annular member having the continuous cylindrical outer surface 54 , and also a cylindrical inner surface 60 . the cylindrical inner surface 60 may be said to define a void at the center of the compressed flow path member 42 between the forward axial surface 56 and the rear axial surface 58 . the invention may be thought of as an injection device , such as the injection devices 10 and 110 , or alternatively , as a flow path member for establishing a flow path along which a solution generated by blending of a liquid solvent and a solid solute may flow , such as the flow path member 42 or 142 . the inventive injection device may be thought of as incorporating a barrier which is opened by rupturing the barrier , as seen in the injection device 10 . alternatively , the barrier may be deflected to open , as seen with the valves 70 and 270 . in a further variation , the barrier may be deformed to open , as seen with the rubbery member 370 . the present invention is susceptible to modifications and variations which may be introduced thereto without departing from the inventive concepts . for example , although the invention has been described with respect to a syringe , the novel principles apply equally to other devices , such as injection devices known as autoinjectors . it would be possible to provide a helical flow path member such as the flow path member 42 which has no central void , or alternatively to permit the flow path member to function on its own in the absence of a core reinforcing member such as the core member 44 . location of a point such as that seen on the pointed finger 66 of fig4 may be relocated . for example , the core member 44 may be provided with a corresponding point to pierce a frangible barrier such as the aluminum foil 41 . while the present invention has been described in connection with what is considered the most practical and preferred embodiment , it is to be understood that the present invention is not to be limited to the disclosed arrangements , but is intended to cover various arrangements which are included within the spirit and scope of the broadest possible interpretation of the appended claims so as to encompass all modifications and equivalent arrangements which are possible .
an injection device such as a syringe , which has a helical flow path for a solution in which the solvent and solute have been introduced . the helical flow path is formed by a helically configured member which has general overall configuration of a helical coil spring . individual coils may be formed to have a groove located along the length of the helix . when compressed , the novel member effectively takes on a cylindrical outer configuration . because the groove is covered and sealed by the surface of the next turn of the helix when compressed , an enclosed helical flow path is formed in the compressed member . the invention may be an injection device using the novel flow path forming member or alternatively , the flow path forming member itself .