the package shown in these drawings essentially comprises a container 1 , namely in this instance a bottle of polyethylene having elastically terminating in a plug 3 at the end nearest the container 1 and in a delivery nozzle 18 at the other end is inserted in the neck 2 of said container in an axial sliding movement . a cap 26 which covers the unit is screwed on the exterior of the neck 2 . the lock - chamber 4 is constituted by a tubular body 7 of revolution , the crenellated base 31 of which is provided internally with an annular peripheral bearing shoulder 10 for a first filter element or upstream filter element 8 which may be constituted by a perforated membrane , a woven fabric element or a sintered plate , as well as a snap - action engagement groove 11a for the plug 3 . the plug 3 has the same external diameter as the tubular body 7 and forms an extension of this latter . its end face is full whilst its opposite face , namely the face located opposite to the first filter element 8 , has an annular peripheral edge 12 located opposite to the annular shoulder 10 of the body 7 . radial channels 13 cut in said peripheral edge open externally opposite to the crenellated recesses 31 of the body 7 and internally into a set - back axial face studded with villosities 22 . intercommunicating channels 24 formed between said villosities ensure that the liquid flows freely beneath the first filter element from or towards the radial channels 13 . the crenellated edge 12 of the plug has an external diameter which is slightly smaller than the internal diameter of the crenellated recesses 31 so as to form a peripheral collector duct 34 of the channels 13 . the periphery of the first filter element 8 is thus maintained applied in fluid - tight manner against the annular shoulder 10 of the body 7 by means of the peripheral edge 12 of the plug 3 which is snap - actingly engaged by means of a lateral peripheral rib 11b in the groove 11a at the end of the body 7 . moreover , the entire remaining portion of its surface on the side nearest the container 1 is held in position by the villosities 22 of the plug 3 . at the end remote from the plug 3 , the body 7 terminates internally in a flared - out portion 14 and externally in an annular flange 15 , the external radial face 16 of which forms a fluid - tight annular support for the periphery of a second filter element or downstream filter element 5 which may be constituted by a microporous membrane or a bacteriological filter . the external lateral face of the annular flange 15 has a circular groove 17a which cooperates with an internal peripheral rib 17b of the pipe of the delivery nozzle 18 in order to ensure snap - on engagement of this latter . the nozzle 18 has an axial delivery duct 21 , one end of which opens to the exterior and the other end of which has its opening at the center of a face studded with villosities 23 between which are formed interconnecting channels 20 . said face is surrounded by a peripheral annular shoulder 19 forming a fluid - tight annular support for the periphery of the second filter element 5 located opposite to the external radial face 16 of the body 7 . the second filter element 5 is thus maintained in fluid - tight manner , by means of its periphery , between the body 7 and the nozzle 18 which are snap - fastened to each other . in addition , said element is supported by the villosities 23 over the remainder of its surface and the liquid can flow freely through the element from or towards the delivery duct 21 . between the first filter element 8 , the second filter element 5 and the internal wall of the body 7 , there is delimited an enclosure forming a lock - chamber 4 which may be filled either partially or completely with a soluble or insoluble substance for modifying the liquid 32 to be delivered . the substance considered may be a salt or a lyophilizate or a purifying substance . fluid - tightness of the unit consisting of lock - chamber 4 and plug 3 within the neck is ensured at each end of neck 2 in the storage position ( fig1 b ) by means of peripheral annular ribs 9a of the plug 3 and 9c of the body 7 and in the position of use ( fig2 ) by means of peripheral annular ribs 9b and 9d of the body 7 . the length of the unit consisting of lock - chamber 4 and plug 3 is such that , in the storage position ( fig1 b ), the base of the plug 3 practically does not project beyond the inner edge of the neck 2 within the container 1 whereas in the position of use ( fig2 ), the plug 3 penetrates into the interior of the container 1 to a sufficient depth to ensure that the channels 13 open freely beneath the inner edge of the neck 2 whereas the bottom radial edge of the annular flange 15 is abuttingly applied on the outer edge 25 of the container neck 2 . in a position of use ( fig2 ), the peripheral edge of the nozzle 18 is applied against the outer edge 25 of the container neck without any interruption of continuity , which thus prevents any possibility of gripping and inopportunely returning the lock - chamber / plug unit to the storage position ( fig1 b ). by way of alternative , the edge of the nozzle could be fitted in an annular recess in the edge of the neck . the cap 26 is screwed onto the threaded outer edge of the neck 2 of the container 1 . its internally threaded skirt has an extension in the form of a breakable guarantee ring 29 which can readily be torn - off for initial use of the package . during storage , said guarantee ring 29 is normally in abutment with the neck base 33 of the container ( fig1 b ) in order to prevent any untimely screwing towards the position of use ( fig2 ). an axial stud 27 seals off the delivery duct 21 of the nozzle 18 whilst an internal annular extension 28 bears on the external face of the nozzle 18 . when the guarantee ring 29 has been torn - off , the cap 26 is screwed - down by hand and produces the downward displacement of the unit consisting of nozzle 18 , lock - chamber 4 and plug 3 until the annular flange 15 abuts against the edge 25 of the neck , thus determining the position of use ( fig2 ) whilst the delivery duct 21 remains closed by the stud 27 . it is then possible to unscrew and remove the cap 26 from the package without displacing the unit consisting of nozzle 18 , lock - chamber 4 and plug 3 . the liquid 32 within the container 1 can then be delivered by pressing the walls in order to force it through the lock - chamber 4 and its filter elements 8 and 5 and in order to deliver it through the duct 21 of the nozzle 18 . in the event of fractional deliveries of liquid , the cap 26 is replaced in position , thus isolating the lock - chamber 4 and consequently the container 1 from the exterior . the air sucked - in by elastic return of the container walls is filtered by the filter elements 5 and 8 and also by the substance 6 which may be enclosed within the lock - chamber , and protects the remaining liquid 32 from any pollution , as well as the interior of the lock - chamber . the alternative embodiments shown in fig8 and 9 relate to a package primarily intended for applications in which it is desired that the interior of the lock - chamber 4 should be isolated from the interior of the container 1 between different periods of use irrespective of the position in which the package is stored . the figures illustrating these alternative embodiments are schematic and the filter elements are not shown in these figures for reasons of clarity . the package of fig8 comprises a lock - chamber 4 associated with a closure device with axial translational motion within the smooth - walled neck 2 of a container 1 . at its outer end , the lock - chamber 4 is covered by a welded , bonded or screwed conical end - piece 35 terminating in an axial nozzle 36 which can be sealed - off at will by means of a conventional cap 37 , said end - piece being such as to constitute gripping means enabling a user to impart a movement of translation to the unit consisting of lock - chamber 4 and plug 38 . the inner end of the lock - chamber 4 constituted by the plug 38 is slidably mounted in a blind end - piece 39 snap - fastened in an internal annular flange 40 derived from the neck base of the container 1 and provided with lateral openings 41 in the vicinity of the blind end - wall . the plug 38 is provided at its outer end with an externally - fitted frusto - conical annular flange 38a whilst the blind - end wall of the end - piece 39 is provided internally with a conicity which is complementary to that of the flange 38a of the plug 38 . the respective dimensions of the plug 38 within the blind end - piece 39 and their displacement are such that , when the unit consisting of end - piece 35 , lock - chamber 4 and plug 38 is moved downwards to the full extent within the blind end - piece 39 and the base of the end - piece 35 is abuttingly applied against the end of the neck 2 , the plug 38 shuts - off the openings 41 and isolates the interior of the container 1 from the lock - chamber 4 and from the exterior , as shown in the right - hand half - view of fig8 . on the other hand , when the end - piece assembly 35 is pulled outwards and the plug 38 is abuttingly applied against the base of the neck 2 , the openings 41 are freed , the interior of the container communicates freely with the lock - chamber 4 and the nozzle 36 opens to the exterior after removal of the cap 37 , as shown in the left - hand half - view of fig8 . fig9 illustrates another alternative embodiment of the package in accordance with the invention and of the obturator in which a lock - chamber 4 is associated with a rotational closure device within the inverted neck 42 of a container 1 . the lock - chamber 4 is limited by a body 43 closed by a snap - fastened conical end - piece 44 terminating in an axial delivery nozzle 45 which can be closed at will by means of a conventional cap 46 . the plug 47 is provided with open portions and with an internal annular shoulder 48 on which is applied the peripheral edge of an upstream filter element , the bottom central face of which is thus freed from the end - wall of the plug 47 . an axial stud 49 extending from the plug 47 is latched in rotation in a wall 50 which partly shuts - off the inner end of the inverted neck 42 . the wall 50 and the plug 47 of the body 43 are provided with identical openings 51 , 52 respectively in circular arcs of less than 180 degrees ( 90 degrees , for example ) which can be moved at will by rotation of the body 43 , either opposite to each other so as to cause the interior of the container 1 to communicate with the lock - chamber 4 and with the exterior via the nozzle 45 after removing the cap 46 , or each and respectively opposite to the plug 47 of the body 43 and to the wall 50 of the inverted neck 42 in order to isolate the interior of the container 1 from the lock - chamber 4 and from the exterior , as shown in fig9 . irrespective of the mode of utilization of the lock - chambers 4 , it is imperative to ensure that the assemblies have seals such that the liquid cannot flow in any direction other than through the lock - chamber . this can be achieved in accordance with conventional practice by means of ribbed lips , beaded edges or elastic seals . fig1 illustrates a preferred embodiment of the package in accordance with the invention in which the unit consisting of lock - chamber 4 and plug 3 is formed in a single piece by a tubular body 7 . the plug 3 constituting that end of the body 7 which is intended to communicate with the interior of the container 1 has a chamber 53 for receiving a product to be mixed with the liquid within the container 1 during initial setting of the package in the position of use . this chamber 53 has a first lateral opening 54 in the periphery of the body 7 at the level of the plug 3 between two peripheral annular ribs 9a , 9b of the body 7 , the rib 9a being applied in fluid - tight manner against the internal periphery of the neck 2 of the container 1 in the storage position of the unit consisting of lock - chamber 4 and plug 3 and the rib 9b being applied in fluid - tight manner against the internal periphery of the neck 2 , irrespective of the position of the unit comprising lock - chamber 4 and plug 3 . an additional peripheral annular rib 9d of the body 7 is provided for perfecting fluid - tightness in the position of use and for ensuring that fluid - tightness is achieved irrespective of the position of use or of storage , by means of two ribs . a second opening 55 of the chamber 53 provides an access to the lock - chamber 4 opposite to an upstream filter element 8 . once the product contained in the chamber 53 has been mixed with the liquid , this second opening serves to establish a communication between the interior of the container 1 and the lock - chamber 4 by means of the chamber 53 which accordingly performs the function of the channels 13 of the embodiment shown in fig1 a , 1b to 5 . the package illustrated in fig1 is also provided with a nozzle 18 having an axial delivery duct 21 , one end of which opens to the exterior whilst the other end has its opening at the center of a face studded with villosities 23 forming intercommunicating channels 20 . said face is surrounded by a peripheral annular shoulder 19 which forms a fluid - tight annular support for the periphery of a downstream filter element 5 opposite to the external radial face 16 of the body 7 . the separation between the lock - chamber 4 and the plug 3 is constituted by a fluid - tight annular shoulder 10 which supports the upstream filter element 8 at the periphery and which forms the opening 55 . a cap which is similar to that described with reference to fig1 a , 1b to 5 and which performs the same function is provided for covering the entire assembly . all the elements of the package can be readily formed by molding identical or different plastic materials or else can be made of various machined materials . the invention is naturally not limited in any sense to the particular features specified in the foregoing or to the details of the particular embodiment which has been chosen in order to illustrate the invention . consideration can be given to all kinds of variants of the particular embodiment which has been described by way of example and of its constituent elements without thereby departing from the scope of the invention . this invention accordingly includes all the means constituting technical equivalents of the means described as well as their combinations .
a package for a liquid which is purified includes a neck with a lock - chamber slidable therein . the lock - chamber includes a purifying substance through which the liquid passes when dispensed . at one end of the lock chamber , a plug is positioned to block passage of the liquid through the lock - chamber when the lock - chamber is projected from the neck and to allow passage of the liquid when the lock - chamber is pushed down into the neck .