EP0497958A1 - A valve for a syringe - Google Patents

Abstract

Disposable syringe, consisting of a cylindrical wall (12) extending to a needle sleeve (11). The wall (12) has an internal cylindrical surface (13) which cooperates with a sliding piston in order to form at least part of a chamber (12) with variable volume. A valve assembly (15) is housed in the chamber (14) and it prevents the reuse of the syringe. The valve includes a valve seat (22) which cooperates with a movable valve member (26), which may be spherical in shape. The valve member (26) can move from the side upstream of the valve seat (22) to the side located downstream of this valve, to avoid re-use of the syringe. The piston (269) (piston head) is permanently retained in the cylindrical body (261) in order to avoid its withdrawal and therefore the reuse of the syringe by filling the syringe through the rear opening of the cylindrical body (261) . The syringe can also comprise a porous disc (174) which makes it possible to accommodate a powdered medicament in said syringe and to inject it then, after mixing and dissolution of said medicament in the syringe from which it can only come out during an injection. .

Description

A VALVE FOR A SYRINGE FIELD OF THE INVENTION The present invention relates to valve mechanisms for single use syringes. BACKGROUND OF THE INVENTION

Disposable syringes for which a single use is contemplated are well known as for example syringes for the injection of insulin in diabetics. Nothing, however, prevents these syringes from being reused in a necessarily unsterile state. The result that contamination syringes when used contribute to the spreading of diseases such as AIDS or hepatitis.

Accordingly It is desirable for syringes to be designed for a single use only to inhibit their re-use and therefore the risk of using contaminated syringes.

Frequently a medication is better stored in a powdered state. Normally where such medication is to be delivered via a syringe, the powder needs to be mixed with a solvent and then drawn Into the syringe for delivery.

The above described method of using powdered medication is generally time-consuming and expensive. DISCUSSION OF THE PRIOR ART

Previously known single use syringes usually incorporate a modification of the piston of the syringe so that it is jammed in its fully inserted position adjacent the needle. These previously known devices have the disadvantage that the piston can become inadvertently jammed prior to a liquid being drawn in to the cylinder of the syringe.

Described in British Patent 1,550,310 and French Patent 2,348,708 is a single use syringe. The syringe has a detachable piston which prevents re-use of the syringe. Once the piston has been moved to the minimum volume position, movement of the piston to again draw in a liquid is prohibited since the piston rod becomes detached from the piston head. This syringe suffers from the disadvantage that the piston can become detached from the piston rod and the syringe cannot be operated to test whether the syringe has been correctly inserted. This is usually achieved by pulling back on the piston rod to draw into the syringe a small portion of blood. A similar syringe is disclosed in British Patent 2,015,883 again this particular device shows a detachable piston which suffers from the disadvantages as discussed.

French Patent 2,298,340 discloses a single use syringe, with the piston being provided with a frangible diaphragm. Once the piston has been moved to the minimum volume piston, a bar penetrates the diaphragm preventing re-use of the syringe. British Patent 1,454,540 is of a similar construction, in that the piston is provided with a means of damaging the body of the syringe preventing its re-use. Both the syringes suffer from the disadvantage that they do not enable operation of the syringe to test whether the needle has been correctly located.

US Patent 3,951,146 discloses a single use syringe with employs a ratchet mechanism to prevent withdrawal of the piston. Again this particular type of syringe does not enable testing to determine whether the needle has been correctly located. British Patent 2,184,657 also uses a pawl to engage behind the piston to prevent re-use. It has the same disadvantages. US Patents 3,478,937 and 3,890,971 also employ pawls or detent members which prevent reward movement of the piston. They suffer similar disadvantages. US Patent 4,233,975 discloses a single use syringe with a plunger member which engages within a socket when the piston is moved to the minimum volume piston. The plunger cannot be retracted and prevents re-use of the syringe.

US Patent 4,650,468 1s similar to several of the above discussed patents since it also uses a plunger or piston which is automatically locked in a position preventing re-use.

The above discussed previously known single use syringes suffer from the further disadvantage in that they require the piston to be moved to the minimum volume of position before any action is taken to render the syringe inoperative.

International Application PCT/AU88/00402 discloses a variety of valve mechanisms for a single use syringe. Each of the valve mechanisms has a movable valve member which is generally complex in shape and therefore may be difficult to manufacture. Still further, the movable valve members are at least partly compressed in their stored state, which may reduce the shelf life of the syringe.

In specification PCT/GB87/00728 (WO88/02640) there is disclosed a syringe having a valve mechanism. The valve mechanism is of a "reed" type in that it is provided with a valve seat with which there is associated a "reed" movable valve member. The "reed" member is movable from one side of the valve seat to the other side of the valve seat. However in this regard it should be appreciated that the "reed" member is at all times permanently attached to the valve body and merely pivots from one position to the next. This particular type of mechanism suffers from the disadvantage that sealing is difficult to obtain and the device prone to failure.

Described in Australian Patent Application 28430/84, in the name of Becton Dickinson & Co describes a 2-component medication syringe. The syringe has its main chamber divided by means of a stopper. One of the sub-chambers receives a powder, and the other sub-chamber receives a liqui to dissolve the powder. During operation of the syringe, the stopper is moved to a position allowing the liquid to mix with the powder. This particular syringe is expensive to manufacture since a stopper 1s required as well as means of rendering the stopper inoperative when the liquid is t be mixed with the powder.

OBJECT OF THE INVENTION It is the object of the present invention to overcome or substantially ameliorate the above disadvantages.

DISCLOSURE OF THE INVENTION There is disclosed herein a single use syringe valve, said valve comprising: a hollow valve body having a longitudinal passage providing at least part of a valve chamber through which liquid to be injected passes; an annular lip, extending Inwardly of said passage from said body, providing an opening and dividing said chamber Into a first and a second sub-chamber; a movable valve member captively located in said chamber and having at least a portion initially located in said first sub-chamber but movable to said second sub-chamber via said opening, which movement is in the direction of flow of the liquid during an injection operation; and wherein said lip and valve member co-operate to prevent movement of said valve member portion from said second chamber to said first chamber, and said valve member operatively closes said opening to liquid flow in the opposite direction to the injection direction when said valve member portion is located in said second sub-chamber, to prevent re-use of the syringe.

In a first preferred form, said valve member is of circular transverse cross-section and more preferably is spherical in configuration. In this preferred form, the movable valve member consists solely of said portion.

As a further preferred construction, the movable valve member includes a further portion, with the movable valve portions being connected. The further portion is at all times located in said second chamber. There is also disclosed herein a syringe comprising: an interacting piston and cylinder co-operating to provide a variable volume working chamber; a passage, including said chamber, extending from said cylinder to communicate with said needle; a porous wall extending transversely across said passage and through which a liquid to be injected passes as said volume is reduced by said piston; a soluble powder located in said passage at a position rearward of said wall; and wherein said porous wall prevents the passage of said powder to said needle until the particle size thereof is reduced below a predetermined size or said powder is dissolved.

There is still further disclosed herein a single use syringe comprising: an interacting piston and cylinder co-operating to provide a variable volume working chamber; a passage, including said chamber, extending from said piston to communicate with a needle; and valve means located in said passage through which liquid to be injected must pass and which prevents re-use of the syringe, said valve means including reed means movable from a first position extending transversely across said passage and preventing the flow of liquid in a reverse direction to an injection direction, and an operative position permitting liquid to pass from said chamber to said needle. There is also disclosed herein a syringe comprising: a cylinder body terminating at one end with a needle mounting, said body enclosing a generally cylindrical cavity; a plunger including a plunger head located in said cavity; and means inhibiting withdrawal of the plunger head from within said cavity through the other end of said body.

BRIEF DESCRIPTION OF THE DRAWINGS Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings wherein: Figure 1 is a schematic part sectioned side elevation of a portion of a single use syringe including a valve to inhibit re-use of the syringe;

Figure 2 is a schematic end elevation of the syringe portion of Figure 1;

Figure 3 is a schematic part section side elevation of the syringe portion of Figure 1 in a further operative position;

Figure 4 is a schematic side elevation of a portion of a single use syringe employing a valve to inhibit re-use of the syringe;

Figure 5 1s a schematic end elevation of the syringe portion of Figure 4;

Figure 6 is a schematic side elevation of the syringe portion of Figure 4, in a further operative portion;

Figure 7 is a schematic end elevation of a movable valve member employed in the syringe of Figure 4; Figure 8 1s a schematic side elevation of the valve member of Figure 7;

Figure 9 is a schematic further end elevation of the valve member of Figure 7;

Figure 10 is a schematic sectioned side elevation of a portion of a single use syringe employing a valve arrangement;

Figure 11 is a schematic side elevation of a further syringe portion employing a valve arrangement;

Figure 12 is a schematic part section side elevation of a portion of a single use syringe including a valve to inhibit re-use of the syringe; Figure 13 is a further schematic side elevation of the syringe of Figure 12;

Figure 14 is a schematic part section side elevation of a single use syringe which is a modification of the syringe Illustrated 1n Figure 12; Figure 15 is a schematic part section side elevation of a single use syringe which is a further modification of the syringe illustrated in Figure 12;

Figure 16 is a schematic sectioned side elevation of a portion of a single use syringe employing a valve to inhibit re-use of the syringe; Figure 17 is a schematic sectioned side elevation of a further syringe portion;

Figure 18 is a schematic sectioned side elevation of the portion of Figure 17;

Figure 19 is a schematic sectioned side elevation of a single use syringe, which is a modification of the syringe of Figure 16; Figure 20 is a schematic parts exploded view of the syringe portion of Figure 19;

Figure 21 is a schematic side elevation (A), sectioned side elevation (B) and end elevation (C) of an alternative valve sleeve to that employed in the single use syringe of Figure 16; Figure 22 1s a schematic end elevation <A>, sectioned side elevation (B) and side elevation (C) of the valve sleeve employed in the syringe of Figure 16;

Figure 23 is a schematic end elevation (A), side elevation (B) and sectioned side elevation (C) of the valve sleeve employed in the syringe of Figure 19;

Figure 24 is a schematic side elevation of the cylinder of a syringe;

Figure 25 is a schematic sectioned side elevation of the end portion of the cylinder of Figure 24, sectioned along the line A-A shown in Figure 26;

Figure 26 is a schematic end elevation of the cylinder of Figure 24;

Figure 27 is a schematic side elevation of the cylinder of Figure 24 in an unassembled configuration;

Figure 28 is a schematic sectioned side elevation of the end portion of the cylinder of Figure 27, sectioned along the line B-B of Figure 29;

Figure 29 is a schematic end elevation of the cylinder of Figure 27;

Figure 30 is a schematic sectioned side elevation of the cylinder of Figure 24, sectioned along the line C-C;

Figure 31 is a schematic side elevation of the end portion of a modified cylinder;

Figure 32 is a schematic sectioned side elevation of the cylinder end portion of Figure 1 sectioned along the line A-A as shown 1n Figure 33;

Figure 33 is a schematic end elevation of the cylinder end portion of Figure 31 ; Figure 34 is a schematic sectioned side elevation of the cylinder end portion of Figure 31, sectioned along the line B-B of Figure 33, in an unassembled configuration;

Figure 35 is a schematic end elevation of the cylinder end portion as illustrated in Figure 34; Figure 36 is a schematic side elevation of a further modified cylinder end portion;

Figure 37 is a schematic end elevation of the cylinder end portion of Figure 36, sectioned along the line C-C;

Figure 38 is a schematic sectioned side elevation of the cylinder end portion of Figure 36, sectioned along the line A-A shown in Figure 39;

Figure 39 is a schematic end elevation of the cylinder end portion of Figure 36;

Figure 40 is a schematic sectioned end elevation of the cylinder portion of Figure 41 ; Figure 41 1s a schematic sectioned side elevation of the cylinder en portion of Figure 36, in an "open" configuration;

Figure 42 is a schematic end elevation of the cylinder end portion a illustrated in Figure 41; Figure 43 is a schematic side elevation of a still further modified end portion of a syringe cylinder;

Figure 44 is a schematic sectioned side elevation of the end portion of Figure 43, sectioned along the line A-A as illustrated in Figure 45;

Figure 45 is a schematic end elevation of the cylinder end portion o Figure 43;

Figure 46 is a schematic sectioned side elevation of the end portion of Figure 43, sectioned along the line B-B of Figure 47;

Figure 47 is a schematic end elevation of the end portion as shown in Figure 46; Figure 48 is a schematic side elevation of a plunger assembly to be employed with any of the previously described syringes or cylinders therefor;

Figure 49 is a schematic end elevation of the plunger assembly of Figure 48, sectioned along the line A-A; Figure 50 is a schematic end elevation of the plunger assembly of Figure 48, sectioned along the line B-B;

Figure 51 is a schematic side elevation of the plunger assembly of Figure 48, in an unassembled orientation;

Figure 52 is a schematic side elevation of a syringe; Figure 53 is a schematic end elevation of the syringe of Figure 52; Figure 54 is a schematic side elevation of the syringe of Figure 1, with the cylinder thereof in an assembled orientation;

Figure 55 is a schematic end elevation of the syringe of Figure 54; Figure 56 is a schematic sectioned side elevation of the syringe of Figure 54, sectioned along the line A-A as shown in Figure 57;

Figure 57 is a schematic end elevation of the syringe shown in Figure 56;

Figure 58 is a schematic side elevation of an end portion of a syringe plunger; Figure 59 is a schematic plan view of the plunger portion of Figure

58;

Figure 60 is a schematic side elevation of the plunger of Figure 58; Figure 61 is a schematic end elevation of the plunger of Figure 60; Figure 62 is a schematic plan view of the plunger of Figure 60; Figure 63 1s a schematic end view of the plunger of Figure 62; and Figure 64 is a schematic sectioned side elevation of the end portion of the syringe shown in Figure 56.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In Figures 1 to 3 of the accompanying drawings there is schematically depicted the leading portion 10 of a single use syringe. The portion 10 includes a needle mounting 11 which extends to a cylindrical wall 12. The wall 12 has a cylindrical internal surface 13 which co-operates with a slidable piston to enclose at least part of a variable volume chamber 14. Extending from the piston 1s a piston rod which is actuated by the user. When the piston is drawn back, the liquid to be injected is drawn into the chamber 14. To inject the liquid, the piston is moved forward reducing the volume of the chamber 14 and forcing the liquid out through the needle mounting 11 and the needle associated therewith. Mounted within the chamber 14 is a valve assembly 15 which prevents re-use of the syringe.

The valve assembly 15 includes a hollow valve body 16 having a first body part 17 co-operating with a second body part 18 to provide a passage 19 through which the liquid passes to be injected. Located within the passage 19 is a valve sleeve 20 which provides a valve chamber 21. The sleeve 20 has a resilient annular Up 22 which divides the chamber 21 into a first sub-chamber 23 and a second sub-chamber 24. The lip 22 also defines a valve opening 25.

Captively located within the chamber 21 Is a movable valve member 26 which in this embodiment is a spherical element. The valve member 26 is formed of rigid relatively inflexible material such as glass or stainless steel .

The body portion 17 has an end wall 27 provided with passages 28 permitting liquid to enter the chamber 21. The body portion 18 has an end wall 29 provided with passages 30 permitting communication between the sub-chamber 24 and the passage 31 of the needle mounting 11.

The sleeve 20, and therefore the lip 22, is formed of resilient material to permit the valve member 26 to pass through the valve opening 25 by a resilient deformation of the lip 22. In operation of a single use syringe employing the portion 10 and more particularly the valve assembly 15, the piston of the syringe is initially in a depressed position adjacent the valve assembly 15. The user draws the piston rearward of the syringe drawing a liquid to be injected through the needle and into the chamber 14 via the needle mounting 31. The liquid passes through the passages 30 and through the sub-chamber 24. Fro the sub-chamber 24, the liquid passes through the valve opening 25 and through the sub-chamber 23 to exit via the passages 28. The movable valve member 26 has a clearance around it relative to the walls defining the sub-chamber 23. Thereafter, the user depresses the piston slightly to expel any air. At this time, or when the liquid is being injected, the valve member 26 will move to block the opening 25. However, due to the pressure applied to the liquid being injected by the user, the valve member 26 resiliently deforms the annular sealing lip 26 so as to pass through the expanded opening 25 to be now located in the sub-chamber 24 as best seen in Figure 3. As the piston is further depressed, the liquid will pass through the passages 28, to enter the sub-chamber 23. From sub-chamber 23, the liquid will pass through the opening 25 and through the chamber 24 to exit via the passages 30. Again the movable valve member 26 has a clearance around it relative to the walls defining the sub-chamber 24. Once the injection process has been completed, the syringe is prevented from re-use since withdrawing the piston to draw liquid into the syringe, will result in the movable valve element 26 abutting the sealing lip 32 and therefore closing the valve opening 25. As can be seen, the annular sealing lip 22 has an abutment face 32 which engages the valve members 26 to prevent movement back through the opening 25. In the reverse direction, the sealing lip 22 provides a frusto-conical ramp surface 33 which aids the movable valve member 26 to deform the sealing lip 22 to permit passage of the valve member 26 from the sub-chamber 23 to the sub-chamber 24. It should be appreciated that the sealing lip 22 is formed of resilient material so that as the valve member 26 passes from the sub-chamber 23 to the sub-chamber 24, the sealing lip 22 is merely resiliently deformed and reassumes Its normal configuration once the movable valve member 26 is located in f-e sub-chamber 24. It is ucsirable in some instances to ensure that the needle has been correctly located, by drawing into the syringe a small amount of blood. This can be achieved when the movable valve member 26 is still located in the sub-chamber 23. When air has been expelled, the user can inser,. the needle and draw back on the piston to draw blood into the syringe. Thereafter when the piston is depressed the pressure within the liquid will force the movable valve member into the sub-chamber 24.

In the initial, or storage position the valve element 26 and/or lip 22 is not stressed.

In the above described embodiment the lip 22 deforms as the valve member 26 is rigid relative thereto. However as an alternative the valve member 26 could deform, as the lip 22 is rigid relative thereto. As a still further alternative, both the lip 22 and valve member 26 could deform. In Figures 4 to 9 of the accompanying drawings there is schematically depicted a portion 40 of a single use syringe. The portion 40 includes the forward end of a cylindrical wall 41 which leads to a needle mounting 42. The needle mounting 42 provides a passage 43 through which liquid passes to be injected via the needle. The 'wall 41 has an internal cylindrical surface 44 which slidably receives a piston to vary the volume of the working chamber 45.

Housed within the cylindrical wall 41 is a valve assembly 46. The valve assembly 46 includes a hollow valve body 47 providing a valve chamber 48. Extending inwardly of the chamber 48 1s an annular sealing lip 49 which divides the chamber 48 into a first sub-chamber 50 and a second sub-chamber 51. The lip 49 is formed integrally with the remainder of the body 47, from resilient material. The lip 49 has a frusto-conical ramp surface 52 and an abutment surface 53 extending in a plane generally normal to the longitudinal axis 54.

Located within the chamber 48 1s a movable valve member 55 having a first portion 56 and a second portion 57. The portion 56 is joined to the portion 57 by means of a neck portion 58.

The neck portion 58 passes through the valve opening 59 defined by the sealing lip 49.

The movable valve member 55 is best seen in Figures 6 to 8. The portion 56 includes a generally cylindrical part 60 provided with one or more longitudinally extending grooves 61. Joining the neck portion 58 with the cylindrical part 60 is a frusto-conical surface 62 which aids the portion 56 to deform the lip 49 and pass through the opening 59.

The second portion 57 includes a cylindrical part 63 which has one or more longitudinally extending grooves 64. An end surface 65 is provided with projections 66 which extend longitudinally of the valve member 55 to abut the surface 53. The grooves 61 are spaced from the longitudinal axis 54 so as to be spaced radially further from the longitudinal axis 54 than the inner extremities of the sealing lip 49. The same applies to the longitudinally extending grooves 64.

The movable valve member 55 is formed of generally rigid material relative to the material from which the lip 49 is formed from.

In operation of a single use syringe employing the valve assembly 46, re-use of the syringe is prevented by transfer of the movable valve portion 56 from the sub-chamber 50 to the sub-chamber 51 by resilient deformation of the sealing lip 49.

Initially, the movable valve member 46 is positioned as illustrated in Figure 4. When in this position, the piston of the syringe would be in a depressed position. The user draws the piston rearward drawing into the space 45 the liquid to be injected. The liquid passes through the needle and needle mounting 42 and through the movable valve member 46 via the grooves 61 and 64. The grooves 64 are held from sealing contact with the wall 53 by the projections 66. The user next depresses the piston slightly to expel any air contained in the syringe. If so required, the needle can then be inserted and the piston withdrawn slightly to draw blood into the syringe to ensure that the needle is correctly located. Thereafter the user depressures the piston applying sufficient force so that the pressure within the liquid forces the portion 56 to deform the lip 49 so that the portion 56 passes through the valve opening 59 to be located in the sub-chamber 51 as illustrated in Figure 6. This movement will not be preventable as the grooves 61 will seal against the surface 52. Accordingly if the liquid is to be injected sufficient force must be applied to cause transfer of the portion 56 to the sub-chamber 51. Once in the sub-chamber 51, the liquid can pass via the grooves 61 and 64 to the injection needle. Once the injection process has been completed, the syringe cannot be re-used. If an attempt is made to draw liquid into the syringe, the cylindrical part 56 will abut the wall 53 and close the valve opening 59. In this regard it should be appreciated that the grooves 61 will seal against the surface 53.

The projections 66 may be eliminated by having the grooves 64 extend to a depth so that they clear the radially inner extremities of the valve opening 59.

In the initial or storage portion with the part 56 located in the sub-chamber, the valve member 55 is not stressed.

In Figure 10 of the accompanying drawings there is schematically depicted a portion 70 of a single use syringe. The portion 70 includes a cylindrical wall 70 which has a cylindrical inner surface 72 which slidingly co-operates with a piston to at least partly enclose a variable volume chamber 73. The forward end of the wall 71 is provided with a needle mounting 74 supporting a needle 75. Located within the chamber 73 is a valve assembly 76 including a hollow valve body 77 formed of resiliently deformable material. The valve body 77 provides a valve chamber 78. The body 77 is provided with an inwardly extending sealing lip 79 dividing the chamber 78 into two sub-chambers 80 and 81. The body 77 has a forward generally annular flange 82 which converges radially inwardly toward the mounting 77. The rear of the body 77 has a further flange 83 which is of an annular configuration. Captively located within the chamber 78 1s a movable valve member 84 which is of generally rigid material relative to the material from which the body 77 is formed. The body 77 would be formed of resiliently deformable material.

The valve member 84 has a first annular sealing ridge 85 which co-operates with the flange 83. A further annular ridge 86 is provided to co-operate with the flange 82. Extending from the ridge 86 are projections 87 which prevent the ridge 86 abutting the surface 88 of the lip 79.

The ridge 85 has a diameter greater than the diameter of the valve opening 89 provided by the lip 79. The ridge 86 has also a diameter greater than the valve opening 89.

In a single use syringe employing the portion 70 and more particularly the valve assembly 76, liquid is drawn into the chamber 73 by liquid passing through the needle 73 and chamber 78. In this regard it should be appreciated that the flange 83 is resiliently deflected radially outwardly to clear the annular ridge 85 to permit liquid to pass thereby. When the piston of the syringe is moved towards the needle 75, pressure within the chamber 73 forces the flange 83 into sealing contact with the ridge 85. The pressure within the liquid then forces the movable valve member 84 to move so as to be located entirely within the sub-chamber 81. This is achieved by resilient deformation of the sealing lip 79 as the ridge 85 passes through the valve opening 89.

Air is then expelled from wlthi.n the syringe. The needle 95 is inserted and the piston is moved to expel the liquid from within the syringe. The liquid is permitted to pass through the valve assembly 76 by resilient deformation of the flange 82 away from the ridge 86.

Re-use of the syringe is prevented by sealing contact between the flange 82 and the ridge 86 as well as abutment of the ridge 85 against the sealing lip 79.

In Figure 11 there is schematically depicted a portion 90 of a single use syringe. The portion 90 includes a cylindrical wall 91 providing a cylindrical surface 92 which sealingly co-operates with a piston to at least partly enclose a variable volume working space 93. The forward end of the wall 91 is provided with a needle mounting 94 which receives a needle 95. Located within the chamber 93 is a valve assembly 96. The assembly 96 includes a hollow valve body 97 providing a valve chamber 98. The valv body 87 is formed of two valve body parts 99 and 100. The part 99 has longitudinally extending ribs 101 placed on opposite sides of the chamber 98. The part 99 is also provided with longitudinally extending recesses 102. The part 100 provides an annular sealing lip 103 defining a valve opening 104. The lip 103 has an abutment face 105. Extending rearwardly from the lip 103 is a frusto-conical ram surface 106 radially diverging toward the forward portion of the syringe. The Up 103 divides the chamber 98 into a first sub-chamber 107 and a second sub-chamber 108.

Located within the chamber 98 is a movable valve member 109 which is formed of resilient material, while on the other hand, the body 79 is formed of relatively rigid material. The valve member has a first portion 116 and a second portion 117. The valve member second portion 117 has an annular flange 110 providing an annular sealing ridge 111. The valve member 109 1s also provided with a rearwardly extending annular flange 112 having an annular ridge 113, forming the first portion 116. Both the ridges 111 and 113 have a radially outer diameter greater than the diameter of the valve opening 104. The surface 106 aids 1n deforming the flange 112 and ridge 113.

Located centrally of the valve member 109 are a series of radially extending projections 114 which retain the valve member 109 1n position by preventing movement of the valve member 109 longitudinally into the sub-chamber 107 beyond the position depicted. In operation of a syringe employing the portion 90 and more particularly the valve assembly 96, liquid is drawn into the syringe by moving the piston away from the needle mounting 94. Liquid enters the needle 95 and passes through the chamber 98 via the recesses 102. The annular flange 112 1s deflected so as to remove the annular ridge 113 from sealing contact with the surface 106. Next, the piston is moved towards the needle mounting 94 to apply liquid pressure to the valve member 109. The valve member 109 is moved so as to be located entirely within the sub-chamber 108. This is achieved by the resilient deformation of the flange 112 and the ridge 113. Once located entirely within the sub-chamber 108, liquid can pass from the sub-chamber 107 to the needle 95 by resilient inward deflection of the flange 110 and annular ridge 111. Liquid also passes by the ridge 113 via the recesses 102. Re-use of the syringe is prevented by sealing contact between the annular ridge 111 and the internal wall 115 of the part 99. Still further, re-use is prevented by sealing contact between the annular ridge 113 and the sealing lip 103.

As an alternative to the use of the projections 114, the ribs 101 could abut the annular ridge 111 to prevent longitudinal movement of the valve member 109 toward the sub-chamber 107 beyond the position depicted. In the initial or start configuration with the first portion 116 located in the sub-chamber 107, the valve member 109 is not stressed.

In Figures 12 and 13 there is schematically depicted the leading portion 120 of a single use syringe. The portion 120 includes a needle mounting or hub 121 which supports the needle 122. The hub 121 is hollow so as to have a frusto-conical wall 123 which engages a valve assembly 125. The valve assembly 125 includes a valve sleeve 124 having a forward portion 126 which is also of a frusto-conical configuration so as to matingly engage with the wall 123. The sleeve 124 has a rear portion 127 which is also of a frusto-conical configuration to engage a forward projection 128 of the syringe barrel 129.

The valve assembly 125 includes a valve chamber 130 which receives a movable valve member 131. The chamber 130 is divided into a forward sub-chamber 132 and a rear sub-chamber 133 by an annular Up 134 which provides a valve opening 152. The lip 134 provides a circular sealing surface 135 which is radially extending and co-axial with respect to the longitudinal axis of the sleeve 124. Extending rearwardly from the sealing surface 135 is a frusto-conical ramp surface 137, which extends to a cylindrical surface 138. The sub-chamber 133 communicates with the interior of the syringe barrel 129. The sub-chamber 133 is encompassed by the surfaces 133 and 138. The sub-chamber 132 is encompassed by the cylindrical surface 136.

Secured to or held in position with respect to the forward end of the sleeve 124, is a filter mesh 139. Forward of the filter mesh 139 is a spacer 154 which abuts against a ridge 141 of the hub 121. The movable valve member 131 has a central shaft 140 which is of circular transverse cross-section so as to be of a cylindrical configuration. Forward of the shaft 140 is a catch portion 141 having radial projections 142. Between the projections 142 are passages 143. Extending from the rear of the shaft 140, is a seal portion 144 having an annular seal surface 145.

In the embodiment of Figures 12 and 13, the sleeve 124 is formed of relatively rigid material, while the movable valve member 131 1s formed of flexible resilient material.

In operation of the above described valve assembly 125, initially the movable valve member 131 is the position depicted in Figure 12. In this position, the syringe may be activated to draw a liquid in through the needle 122 and to pass through the valve assembly 125 via the chamber 130 to the barrel 129 of the syringe. More particularly, the liquid passes through the passages 143. The seal portion 144 is dimensioned so that liquid can pass between it and the surface 138.

Air is then expelled from the syringe which air passes between the sealed portion 144 and the surface 138, and through the passages 143 to exit via the needle 122. Once liquid engages the rear of the sealed portion 144, t< .novable valve member 131 is moved along the ramp surface 137 to cause resilient compression of the seal portion 144. Eventually, the seal portion 144 will be deformed so as to pass the Up 134 to be located in the sub-chamber 132. Accordingly, under the influence of a pressure differential existing across the seal portion 144, the seal portion 144 is moved from the sub-chamber 133, to the sub-chamber 132. During movement the valve member 131 is resiliently deformed.

Th_, vable valve member 131 is depicted in Figure 13 as totally located within the sub-chamber 132. In th-« position, liquid can pass between the seal portion 144 and the surface 136 due to the relative dimensions thereof. After pas^c'ιg the seal portion 144, the liquid passes through the passages 143 to exit via the needle 122.

As can be seen from Figure 13, the movable valve member 131 does not extend the full length of the sub-chamber 132. This permits a small amount of blood to be drawn back Into the syringe to check to ensure that the needle 122 has been correctly inserted. Thereafter, the liquid contained in the syringe is expelled through the needle 122.

Re-use of the syringe is not permitted by the valve assembly 125, since the movable valve member 133 is moved rearwardly so that the annular sealing surface 145 sealingly engages the sealing surface 135, effectively closing the valve opening 152.

As can be seen from Figure 12, the projections 142 retain the movable valve member 131 in the correct position prior to use.

Preferably the valve assembly 125 would be provided with a grid or other means which would inhibit tampering with the movable valve member 131 through the rear of the sleeve 124. It is also preferred that the valve assembly 125 once located on the barrel 129, is fixed thereto and cannot be removed.

The surface 137 aids in- deforming of the seal portion 144.

As a modification of the above described valve assembly 125 of Figures 12 and 13, the movable valve member 131 may be constructed of a relatively rigid material, and the sealing lip 134 located of a resilient material. Accordingly movement of the valve member 131 past the lip 134 would be accommodated by a resilient deformation of the lip 134. In Figure 14 there is schematically depicted a modification of the valve assembly 125 of Figures 12 and 13. In this embodiment, the valve assembly 125 has its sleeve 124 formed integral with the barrel 129 of the syringe. Also the spacer 154 is formed integral with the hub 121 and the filter mesh 139 is directly sandwiched between the leading portion of the sleeve 124 and the hub 121.

In this embodiment the seal portion 144 has a real recess 153, to enhance the flexibility of the seal portion 144.

In Figure 15 there 1s schematically depicted a further modification of the valve assembly 125 of Figures 12 and 13. In this embodiment, the hub 121 totally encases the valve assembly 125. More particularly, the hub 121 has a frusto-conical surface or cylindrical surface 146 which matingly engages with the outer surface 147 of the sleeve 124. Still further, the hub 124 has an annular ridge 148 which engages a grid member 149 which inhibits tampering with the valve assembly 125 through the rear of the hub 121. The filter mesh 139 is sandwiched between the end of the sleeve 124 and the forward end of the hub 121.

To permanently secure the hub 121 to the forward portion 128 of the barrel 129, there is provided a plurality of annular barbs 150 which matingly engage with annular recesses 151 formed in the hub 121.

In the preferred embodiment of Figure 15, the sleeve could be an interference fit in the hub 121 so that it is retained in position frictionally, or alternatively, the member 149 could lock the sleeve 124 in position by being a "snap" fit 1n the sleeve. Again, the sleeve 124 is formed of a relatively inflexible rigid material and the movable valve member 131 of a relatively flexible resilient material. As a modification, the sleeve 124 could be formed of the resilient material and the movable valve member 131 of the relatively rigid material . In the embodiments of Figures 12 to 15, the movable valve member 131 and/or lip 134, are not stressed in the initial or storage configuration when the seal portion 144 is located in the sub-chamber 133.

In Figures 16 and 22 there is schematically depicted the leading portion 160 of a single use syringe. The portion 160 includes a needle mounting 161 which extends to a cylindrical wall 162. The wall 162 has a cylindrical internal surface 163 which sealingly co-operates with a slidable piston to at least partly enclose a variable volume working chamber 164. Extending from the piston is a piston rod which is actuated by the user. Means would be provided to prevent the piston being withdraw from within the chamber 164. When the piston is drawn back, liquid to be injected is drawn into the chamber 164. To inject the liquid, the piston is moved forward reducing the volume of the chamber 164 and forcing the liquid out through the needle mounting 11 and the needle associated therewith.

The chamber 164 projects forward from the cylindrical surface 163 and receives a valve assembly 165. The valve assembly 165 prevents re-use of the syringe.

The valve assembly 165 includes a hollow valve body 166 which includes a generally cylindrical portion 167 from which there forwardly projects a generally frusto-conical portion 168. The portion 168 has an inner frusto-conical wall 193 extending to the opening 169. The portion 168 terminates at the valve opening 169. The valve opening 169 communicates with a valve chamber 170 within which there is captively located a movable valve member 171, which in this particular embodiment is cylindrical in configuration. The valve member 171 is captively located within the chamber 170 by means of projections 172 which are part of the cylindrical portion 167. There are three projections 172, which are equally angularly spaced about the longitudinal axis of the cylindrical portion 167. The projections 172 are shaped so that the valve member 171 can be moved there past to be located in the position depicted in Figure 67. This enables assembly of the valve member 171 within the chamber 170. To achieve this, the cylindrical portion 167 and/or valve member 171 are resiliently deformed. The valve assembly 165 is located within the needle mounting 61 by means of an internal step 173 and a porous disc 174 which is snap-engaged within an annular groove 175.

The frusto-conical portion 168 is resiliently defor able and/or the valve member 71 is resiliently deformable to allow the valve member 171 to pass through the valve opening 169 to be located in a forward sub-chamber 176.

The forward end of the needle mounting 161 is provided with longitudinally extending fins- 177 which engage the valve member 171, when located in the sub-chamber 176, to prevent it sealing against the internal lip 178 of the needle mounting 161. The needle mounting 161 is provided with a longitudinally extending passage 179 into which the fins 177 project. Additionally projecting internally of the passage 179 is an abutment 180 which provides for a tortuous path in respect of the passage 179.

In operation of the above-described valve assembly 165, a liquid may be drawn into the syringe by rearward movement of the piston. With the valve member 171 located within the chamber 170, liquid may pass about the valve member 171. When a liquid is to be injected, the piston is moved forward and pressure within the liquid forces the valve member 171 through the opening 169 via resilient deformation of the valve member 171 and/or the frusto-conical portion 168. Once the movable valve member 171 is located in the sub-chamber 176, liquid is permitted to pass the valve member 171 due to its abutment with the fins 177. Re-use of the syringe is prevented since any attempt to move the piston in a rearward direction, and draw a liquid into the syringe, will result in the movable valve member moving back into engagement with a valve seat 181 surrounding the valve opening 169.

The abutment 180, prevents tampering with the valve member 171 by passing rearwardly through the passage 178 an elongated probe to damage or dislodge the valve member 171 when it is located in the sub-chamber 176.

The porous disc 174 permits liquid flow through it. It also inhibits particles passing through to the needle. This is particularly advantageous if the syringe is provided with a powder in the sub-chamber 181. In this particular configuration, a medication in the form of a powder may be stored in the syringe and subsequently injected upon being mixed and dissolved in a liquid drawn into the syringe.

In Figures 17 and 18 there is schematically depicted a modification of the syringe portion 160 of Figures 16 and 17. In this particular embodiment, the porous disc 174 has been eliminated and the valve body 167 is provided with an annular projection 182 which snap engages within an annular recess 183 formed in the needle mounting 161.

In Figure 19 there is schematically depicted a still further modification of the syringe portion 160. In this particular embodiment, the valve body is provided with a rear wall 184 having a slot 185 through which liquid may pass. The slot 185 divides the rear wall 184 into two flaps 186 which are resiliently deformed to permit assembly of the valve member 171 in the chamber 170.

Still further, the needle mounting 161 is divided into a cylindrical hub 187 and a needle mounting adaptor 188. The hub 187 has an annular projection 189 which snap engages within an annular recess 190 formed in the adaptor 188. The adaptor 188 is provided with the step 173 while the wall 162 is also provided with a step 191. The valve body 166 has an annular flange 192 which is sandwiched between the end of the adaptor 188 and the step 191. This particular embodiment facilitates assembly of the valve assembly 165 in the syringe by enabling location of the valve body 166 in the chamber 164 whereafter it is held in position by means of the adaptor 188. In Figure 21 there is schematically depicted a valve member 200 to replace the valve assemblies 165. In this particular embodiment, the valv member 200 consists of a alve body 201 which has a cylindrical portion 202, from which there forwardly projects a conical portion 203. The conical portion 203 has a transverse slit 204 which divides the conical portion 203 into two reeds 205. The reeds 205 act as a reed valve. The reeds 205 permit liquid to flow 1n the injection direction. In this particular embodiment, the syringe would need to be preloaded with a liquid to be injected.

In the above described embodiments, the movable valve member or the lip are resiliently deformable. It is also contemplated that both are resiliently deformable to permit movement of the valve member, or portion thereof through the valve opening.

In Figures 24 to 30 there is schematically depicted a syringe cylinder 210. In Figure 25, the cylinder 210 is depicted so as to captively locate within it the plunger head of a plunger assembly. In Figures 27 and 30, the cylinder 210 is arranged to permit assembly of the plunger with respect to the cylinder 210.

The cylinder 210 includes a generally cylindrical hollow body 211 provided at its forward end with a neecl mounting 212 and a cavity 213 to receive a valve assembly 214. The valve assembly 214 may be the valve assembly shown in Figure 23. The rear end portion of the body 211 is provided with a finger grippable flange 215 which extends laterally on either side of the body 211. There is also formed with the flange 215 a pair of pawls 216. The pawls 216 are movable from a radially outer position, permitting the assembly of a plunger assembly with respect to the cylinder 210, and a radially inner position retaining the plunger head captive within the cylinder body 211. The captive position is illustrated in Figures 24 to 26, while the position permitting assembly is illustrated in Figures 27 to 29. Each pawl 216 is pivotally attached to the flange 215 by means of a narrow web 217 which deforms to permit its associated pawl 216 to move from its outer position to its inner position. Still further, each pawl 216 is provided with a recess 218 and a projecting portion 219. The cylinder body 211 is provided with a pair of apertures 220 which are aligned to receive the pawls 216 and so that portions 221 of the cylinder body 211 snap engage within recesses 218. In the captive position, the projecting portions 219 project internally of the cylinder body 211 and prevent withdrawal of the plunger head. By captively locating the plunger head within the cylinder body 211, tampering with a valve assembly mounted internally of the cylinder body 211 1s inhibited. Still further, it prevents re-use of a syringe employing a one-way valve assembly by merely reloading the syringe from the rear of the cylinder 210 via withdrawal of the plunger head and subsequent insertion thereof once the cylinder body 211 has been recharged. In respect of the above pawls 216, it should be appreciated that they snap engage with the body 211 in such a way that movement to their radially outer positions.

In Figures 31 to 35, there is schematically depicted a modification of the syringe cylinder 210. In this particular embodiments pawls 230 are of a rectangular configuration and are deformed to be located within the apertures 220.

In Figures 36 to 42 there is schematically depicted an alternative means of captively locating the plunger head within the cylinder body. In Figures 36 to 42 there is schematically depicted a cylinder 240 for a syringe. The cylinder 240 has a cylinder body 241 which in its initial configuration, is of a cylindrical configuration as shown in Figure 41. However, once the plunger head has been inserted in the body 241, side portions 242 of the body 241 are plastically deformed so as to project inwardly and prevent withdrawal of the plunger head. In Figures 43 to 47, there is schematically depicted a syringe cylinder 240. The syringe cylinder 240 has a body 241 provided at one extremity with a finger grippable flange 242. In this particular embodiment, there is provided a pair of deformable projections 243, which are movable from a radially outer position, permitting assembly of a plunger with respect to the cylinder 240, and a radially inner position preventing withdrawal of the plunger head. The captive position with respect to the plunger head is illustrated in Figures 44 and 45.

The above described cylinders of Figures 24 to 47, are formed of plastics material with the cylinder bodies and associated pawls and/or projections formed integral therewith together with the finger grippable flanges.

In Figures 49 to 51, there is schematically depicted a plunger assembly 250 to be used in conjunction with any one of the previously described cylinders. The plunger assembly 250 includes a plunger shaft 251 provided at one end with a plunger head 254. The plunger shaft 251 consists of two longitudinally extending shaft portions 252 and 253, which are pivotally attached to the plunger head 254 by narrow webs 255. The shaft portions 252 and 253 are provided at their extremities with flange portions 256 which co-operate to provide a flange to be gripped by the user. The shaft portion 252 1s provided adjacent Its extremity, with a shaped recess 257 which snap engages a complementary shaped projection 258 formed on the portion 253. Accordingly, the plunger 250 in its assembled state has a central longitudinally extending aperture 259. The aperture 259 is intended to co-operate with the pawls described in Figures 24 to 35, and the projections 243 of Figures 43 to 47. Still further, the aperture 259 would co-operate with the deformed portions 242 of Figures 36 to 42. In Figures 52 to 57, there 1s schematically depicted a single use syringe 260. The syringe 260 includes a syringe cylinder 261 provided at its forward end with a needle mounting 262 to receive a syringe needle 263. Provided internally of the cylinder body 264 is a one way valve 265, which may be the one way valve of Figure 22. The needle mounting 261 and the valve 265 are more clearly seen In Figure 64.

The cylinder body 264 1s provided at its rear extremity with a finger grippable flange 266 and a pair of apertures 267. Pivotally mounted on the flange 266 are a pair of pawls 268 which are movable from an outer position (Figure 52) to an inner position (Figure 56). In the position shown in Figure 52, the rear of the cylinder body 254 is open to permit insertion of the plunge head assembly 269. Once the head assembly 269 is located internally of the cylinder body 261, the pawls 268 are pivoted and deformed so as to pass through the apertures 267. Once located in the position shown in Figure 56, the pawls cannot be returned, and prevent withdrawal of the plunger head 269 through the rear of the cylinder body 261. This then prevents re-use of the syringe by withdrawing the plunger head 269 a^d filling the syringe from the rear.

The pawls 268 are each pivotally mounted via shafts 270 supported by the flange 266.

The plunger 271 includes a longitudinally extending plunger shaft 272 provided with longitudinally extending recesses 273 within which the pawls 268 engage. For example, a plunger assembly 280 is shown in Figures 58 to 63. The plunger assembly 280 includes a shaft 281 which has longitudinally extending recesses 282 which would co-operate with the pawls 268 of the previous embodiment. The plunger assembly 280 further includes a plunger head 283 provided with a sealing ring 284 (or washer). The rear end of the shaft 281 is provided with a finger grippable flange 285.

Claims

CLAIMS :

1. A single use syringe valve comprising: a hollow valve body having a longitudinal passage providing at least part of a valve chamber through which liquid to be injected passes; an annular lip, extending inwardly of said passage from said body, providing an opening and dividing said chamber into a first and a second sub-chamber; a movable valve member captively located in said chamber and having at least a portion initially located in said first sub-chamber but movable to said second sub-chamber via said opening, which movement is in the direction of flow of the liquid during an injection operation; and wherein said lip and valve member co-operate to prevent movement of said valve member portion from said second chamber to said first chamber, and said valve member operatlvely -loses said valve to liquid flow in the opposite direction to the injection direction when said valve member portion is located 1n said second sub-chamber, to prevent re-use of the syringe.

2. The valve of claim 1, wherein said movable valve member is initially located entirely in said first sub-chamber, and is entirely located in said second sub-chamber to prevent re-use of the syringe by sealingly engaging said Up.

3. The valve of claim 2, wherein said movable valve member is spherical in configuration, and said opening is of a circular configuration with a diameter smaller than said valve member, with said valve member and/or lip being resiliently deformed to permit movement of said valve member from said first sub-chamber to said second sub-chamber.

4. The valve of claim 3, wherein said valve body is adapted to be received within an outer annular wall of a syringe.

5. The valve of claim 4, wherein both sub-chambers are located within said body.

6. The valve of claim 4, wherein said valve body only encloses said first sub-chamber.

7. The valve of any one of claims 3 to 6, wherein said valve body consists of a hollow cylindrical portion, and a frusto-conical portion extending co-axially forward of the cylindrical portion, and wherein said frusto-conical portion provides said annular lip terminating at said valve opening, said frusto-conical portion having an internal frusto-conical surface which engages the valve member during transfer thereof from said first chamber to said second chamber.

8. The valve of any one of claims 3 to 7, further including means to captively locate said valve member in said first sub-chamber to prevent movement of said valve member in said opposite direction out of said first sub-chamber.

9. The valve of claim 8, wherein the means to captively locate said valve member includes projections on said valve body projecting inwardly of said passage at a position rearward of said valve member.

10. The valve of any one of claims 3 to 9, further including a porous wall at the rear of said first sub-chamber and through which liquid must pass to be injected and wherein said porous wall Inhibits the passage of particles above a pre-determ1ned size passing therethrough.

11. The syringe of claim 9, wherein the means to captively locate said valve member includes a wall which 1s transversely slit so as to divide said wall into at least two resilient flaps which are deformed to permit assembly of the valve member into said first sub-chamber.

12. The valve of claim 10, wherein said porous wall retains said valve body in position in a syringe.

13. The valve of claim 4, wherein said valve body has means to co-operate with said annular wall to retain the valve body in position.

14. A single use syringe comprising: the valve of any one of claims 1 to 13; a needle mounting within which said valve is located; and wherein said needle mounting includes a longitudinal passage into which there projects an abutment to cause the passage of said needle mounting to follow a tortuous path to Inhibit access to said valve member from the forward end of the needle mounting.

15. A single use syringe comprising: the valve of claim 6; a needle mounting within which the valve is located; and wherein said needle mounting co-operates with said valve body to substantially enclose said second sub-chamber.

16. The syringe of claim 15, further including projection means to engage the valve member in said second sub-chamber to prevent said valve member from blocking the flow of liquid in said injection direction.

17. A single use syringe comprising: the valve of any one of claims 1 to 16; a needle mounting within which said valve is located, and wherein said needle mounting includes a mounting hub enclosing the valve, and a needle adaptor attached to the hub and engaging the valve body to retain the valve body within the hub.

18. The valve of any one of claims 3 to 17, wherein said movable valve member is resiliently deformable.

19. The valve of any one of claims 3 to 17, wherein said annular li is resiliently deformable.

20. The valve assembly of claim 1, wherein said movable valve membe consists of a first portion constituting the valve member portion initiall located in said first sub-chamber, and a second portion captively located in said second sub-chamber, and wherein said first portion is moved from said first sub-chamber to said second sub-chamber to prevent re-use of the syringe.

21. The valve of claim 20, wherein said first portion has a leading inclined surface defining an acute angle with respect to the longitudinal axis of the valve, and which engages the lip to aid 1n movement of the first portion to said second sub-chamber.

22. The valve of claim 20, wherein said lip has an inclined surface engaged by said first portion to aid in movement of the first portion from said first sub-chamber to said second sub-chamber.

23. The valve of claim 20, wherein said first portion has a transverse dimension greater than that of said opening, and said first portion and/or said Up is/are deformed to permit movement of said first portion from said first sub-chamber to said second sub-chamber.

24. The valve of claim 23, wherein said first portion sealingly engages said lip when located in said second sub-chamber to close said opening, to thereby prevent re-use of the syringe.

25. The valve of claim 24, wherein said first portion has longitudinally extending passage means which permit liquid to flow past said first portion when said first portion is in said first sub-chamber, which passage means are closed by said lip when said first portion is located in said second sub-chamber.

26. The valve of claim 25, wherein said passage means are longitudinally extending grooves on the periphery of said first portion.

27. The valve of claim 24 or 25, wherein said second portion has longitudinally extending passage means to permit liquid to flow past said second portion.

28. The valve of claim 23 or 24, wherein said lip is resiliently deformable.

29. The valve of claim 23 or 24, wherein said movable valve member is resiliently deformable.

30. The valve of claim 23 or 24, wherein said lip is resiliently deformable, and said valve further includes an annular sealing flange extending longitudinally of said passage from said lip into said first sub-chamber which engages said first portion, and which is resiliently deflectable therefrom to permit liquid to pass through said chamber in said opposite direction.

31. The valve of claim 30, further including a resilient annular sealing flange extending longitudinally of said passage from said lip into said second sub-chamber to sealingly engage said second portion, when said first portion 1s located in said second sub-chamber, to prevent re-use of the syringe but is resiliently deflectable from sealing contact with said second portion when liquid is moved in said injection direction through said chamber.

32. The valve of claim 31, wherein said first portion is provided with an annular ridge to engage the annular flange projecting into said first sub-chamber, and said second portion is provided with an annular ridge to engage the annular flange projecting into said second sub-chamber.

33. The valve of claim 32, further including means to maintain said second portion from sealingly closing said valve opening.

34. The valve of claim 23, wherein said valve member is formed of resilient material, and said body Includes a sealing surface extending longitudinally of said passage from said lip into said first chamber, and wherein said first portion Includes an annular sealing flange engaging said sealing surface when located in said first sub-chamber, and said first portion engages said lip to sealingly enclose said valve opening when said first portion is located in said second sub-chamber.

35. The valve of claim 34, wherein said annular sealing flange is resiliently deformed when passing through said opening.

36. The valve of claim 34, further including means to permit liquid to pass said first portion in said injection direction, when said first portion is located in said second sub-chamber.

37. The valve of claim 35, wherein the means to permit the flow of fluid in said injection direction includes projection means to resiliently deform said annular flange.

38. The valve of claim 23, 34 or 36, wherein said valve member is formed of resilient material and said body includes a sealing surface extending longitudinally of said passage from said lip and located in said second sub-chamber, and said valve member further includes an annular sealing flange to engage the sealing surface within said second chamber when said first portion 1s located in said second sub-chamber, to prevent re-use of the syringe.

39. The valve of claim 38, further including means to permit liquid to pass in said opposite direction past the sealing flange engagable with the sealing surface of said second sub-chamber, when said first portion is located in said first sub-chamber.

40. The valve of claim 20, 23 or 24, further including a first surface extending longitudinally of said passage from said lip into said first sub-chamber, and a second surface extending from said lip into said second sub-chamber, said first and second surfaces being adapted to operatlvely co-operate with said first portion to cause movement of said valve member.

41. The valve of claim 40, wherein said valve member Includes a shaft portion connecting said first and second portions, which shaft portion extends through said opening when said first portion is located in said first sub-chamber.

42. ^τhe valve of claim 41, wherein said first portion is of a generally t cular transverse cross-section and said opening is of a generally circular configuration, with said first portion having a diameter greater than the diameter of said opening.

43. The valve of claim 42, wherein said second portion has a transverse dimension greater than the diameter of said opening to prevent movement of said second portion through said opening Into said first sub-chamber.

44. The valve of claim 39, wherein said movable valve member is formed of resilient material, so that said first portion is deformed to permit movement of said first portion from said first sub-chamber to said second sub-chamber.

45. The valve of claim 44, wherein said second portion includes projections which engage said lip to prevent movement of said second portion from said second sub-chamber to said first sub-chamber.

46. The valve of cla n 45, wherein said first sealing surface deludes a s face portion of frusto-conical configuration tapering in said injection direction to aid in transfer of said first portion from said first sub-chamber to said second sub-chamber.

47. The valve of claim 1 or 20, further including a filter means located in said passage through which said liquid must pass.

48. The valve of claim 39, further Including a filter means located in said passage through which liquid must pass.

49. The valve of claim 45, wherein said first portion has a rear aperture to aid in resilient deformation of said first portion as it passes through said opening.

50. The valve of claim 39 or 43, wherein said first portion sealingly engages said lip when located in said second sub-chamber, to prevent re-use of the syringe.

51. A syringe comprising: an interacting piston and cylinder co-operating to provide a variable volume working chamber; a passage, including said chamber, extending from said cylinder to communicate with said needle; a porous wall extending transversely across said passage and through which a liquid to be injected passes as said volume is reduced by said piston; a soluble powder located in said passage at a position rearward of said wall ; and wherein said porous wall prevents the passage of said powder to said needle until the particle size thereof 1s reduced below a predetermined size or said powder is dissolved.

52. The syringe of claim 51, wherein said wall extends across said chamber at a forward position thereof.

53. The syringe of claim 51 or 52, further including the valve assembly of any one of claims 1 to 50, located in said passage to prevent re-use of the syringe.

54. A single use syringe comprising: an interacting piston and cylinder co-operating to provide a variable volume working chamber; a passage, including said chamber, extending from said piston to communicate with a needle; and valve means located in said passage through which liquid to be injected must pass and which prevents re-use of the syringe, said valve means including reed means movable from a first position extending transversely across said passage and preventing the flow of liquid in a reverse direction to an injection direction, and an operative position permitting liquid to pass from said chamber to said needle.

55. The syringe of claim 54, wherein said valve means comprises a generally cylindrical valve body and a frusto-conical portion extending forwardly of said body, said frusto-conical portion being divided to provide at least two reed members which are resiliently deflectable between the closed position and the operative position.

56. A valve for a single use syringe substantially as hereinbefore described with reference to the accompanying drawings.

57. A syringe comprising: a cylinder body terminating at one end with a needle mounting, said body enclosing a generally cylindrical cavity; a plunger including a plunger head located in said cavity; and means inhibiting withdrawal of the plunger head from within said cavity through the other end of said body.

58. The syringe of claim 57, wherein said syringe is a single-use syringe.

59. The syringe of claim 58, wherein said means includes projection means projecting Internally of said cavity at a position adjacent said other end and positioned to engage said plunger head when said plunger head approaches said other end.

60. The syringe of claim 59, wherein said projection means are pawls which are movable between a first and a second position, with said pawls when in said second position preventing withdrawal of said plunger head.

61. The syringe of claim 60, wherein said pawls when in said first position permit the plunger head to be inserted through said other end to be located in said cavity.

62. The syringe of claim 59, wherein said projection means include portions of said cylinder body deformed so as to project radially inwardly.

63. The syringe of claim 59, wherein said projection means are deformable projections which are movable from a radially outer position permitting said plunger head to be located 1n said cavity through said other end, and a radially inner position preventing withdrawal of said plunger head.

64. A single use syringe, substantially as hereinbefore described with reference to the accompanying drawings.