Abstract:
A device is placed upon a container that is sealed by a sealing element and filled with a liquid, the device allowing the liquid to be withdrawn. The device is provided with a penetration element with a hollow needle that is held in an unused position on a head section. The penetration element is held by guide elements on the head section so that the element can be pressed against the sealing element in a withdrawal position, in which the hollow needle penetrates the sealing element. At least one aeration channel is provided to equalize the pressure in the container during the withdrawal of the liquid, the channel running preferably along the hollow needle. The air sucked from the atmosphere enters the aeration channel via a filter. This prevents the contamination of the liquid and the latter can be withdrawn without the risk of a reverse flow.

Description:
This is a National Phase Application filed under 35 U.S.C. 371 as a national stage of PCT/EP2011/072716, filed Dec. 14, 2011, and claims priority from European Application No. 10195706.6, filed Dec. 17, 2010, the content of each of which is hereby incorporated by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     The invention relates to a device for withdrawing a liquid from a container according to the preamble of claim  1 . Here, devices for needle-free withdrawal of pharmaceutical substances from a hermetically sealed glass vessel are generally concerned. Here, the liquid can be transferred into an injection syringe, wherein the needle is only fitted subsequently. Of course, devices of this type can also be used in the non-medical field however, for example for chemical analysis purposes in the food processing field, etc. 
     A generically comparable device is known by WO 01/60436, in which a linearly displaceable piercing tip is held in a tubular housing, which is fitted onto the closed container mouth. The piercing tip is fixed in the above idle position by flexible detent catches and has a circumferential toothing, which engages in corresponding lateral tooth segments. In the event of application of a pressure from above in the direction of the container once a syringe has been attached, the piercing tip releases from the latched connection and slides downwardly in the toothing in a manner fixed against rotation until the sealing plug on the container has been pierced. The container content can then be aspirated by means of the injection syringe. 
     A significant disadvantage of known devices lies in the fact that, even once the sealing element has been pierced by the hollow needle, the interior of the container is sealed with respect to the atmosphere when another container, such as an injection syringe, is attached to the penetration element. As the liquid is aspirated from the container, a negative pressure is thus produced, which in extreme cases causes the majority of the liquid to flow back into the container as soon as the pump movement is interrupted. Due to the flexibility of the sealing element, air may flow along the outer face of the hollow needle with a strong negative pressure in the container. This is undesirable however because microbiological impurities can thus infiltrate the container and therefore the liquid. 
     SUMMARY OF THE INVENTION 
     One object of the invention is therefore to create a device of the type mentioned in the introduction, with which the aforementioned disadvantages are avoided and with which a backflow of liquid into the container is avoided, in particular whilst maintaining sterile conditions. The device should also function reliably and should also be easy to operate by individuals not trained specifically for this purpose. In addition, it should be possible to produce the device in a simple and cost-effective manner, since the device is a component of a disposable packaging that has to be disposed of after use. 
     These objects are achieved in accordance with the invention by a device having the features in claim  1 . The at least one aeration channel running preferably along the hollow needle evidently causes the interior of the container to be short-circuited to the atmosphere in the withdrawal position. The build-up of a continuously increasing negative pressure in the container is thus avoided, since as much air flows into the container as liquid is withdrawn. In spite of this, a dirt-free and even germ-free environment in the container is ensured when, in accordance with a further embodiment, the fed air has to pass a filter. Depending on the nature of this filter, the smallest of particles or living beings can also be retained. Of course, it is conceivable to arrange a plurality of aeration channels and for these to extend along the hollow needle linearly or also helically. The arrangement of an aeration channel on an element separate from the hollow needle, for example in the form of a separate aeration needle, would also be conceivable. 
     The aeration channel is particularly advantageously formed however as a groove on the outer face of the hollow needle. There are preferably a plurality of parallel grooves. A component of this type can be easily produced, and, with sufficient groove depth, a sufficiently large passage cross section is kept clear, even if the sealing element consists of very soft and resilient material. 
     The filter can be arranged fundamentally on the penetration element and can be displaced together therewith, or it may be held rigidly on the head piece. It is important in this case that the side of the filter facing towards the aeration channel is a component of a chamber that is delimited in a sterile manner with respect to the atmosphere. The filter may for example be arranged on the penetration element, preferably at the atmosphere-side end of the aeration channel, for example more specifically on a collar that surrounds the hollow needle, is provided with openings and simultaneously supports or carries the filter. This variant arranged close to the aeration channel has the advantage that the area of the filter can be kept relatively small. 
     With an assignment of the filter on the head piece, the arrangement is preferably provided in a region facing towards the sealing element. Here, the filter may be arranged in a mount, which surrounds the penetration element in an annular manner. This arrangement has the advantage that the space to be kept sterile in the idle position can be kept very small. 
     Further advantages can be achieved if the guide means comprise at least one wall portion, which connects the penetration element to the head piece and holds said penetration element in the idle position, wherein the wall portion is deformable in such a way that it guides the penetration element until the withdrawal position is reached. Due to the fixed connection between the head piece and the penetration element, an anti-rotation lock is ensured and good straight-line guidance is also produced as a result of the deformability. An embodiment of this type of the guide means would also be very advantageous on conventional devices without an aeration channel and without a filter. 
     The deformable wall portion may for example be at least one resilient membrane surrounding the penetration element. This membrane may be deformable in such a way that it fixes the penetration element in the withdrawal position under the spring bias. As a result of its spring properties, the dome-like membrane is thus biased both in the idle position and in the withdrawal position. Here, the “clicker” effect of the membrane is utilized. Of course, detent means may also be provided however in order to fix the penetration element in the withdrawal position, such that the spring bias of the membrane is irrelevant for maintaining the withdrawal position. 
     The membrane can be formed rather differently and for example may also consist in the circumferential direction of a plurality of separate segments. 
     Atmospheric air can flow via the gaps between the segments in the withdrawal position. It is also conceivable however for a membrane closed in the idle position to be provided with predetermined breaking points, which rupture when the penetration element is transferred into the withdrawal position. Predetermined breaking points of this type have the advantage that the membrane is relatively dimensionally stable in the idle position and only has increased elasticity once the predetermined tearing lines have ruptured. In addition, air from the atmosphere can also flow here via the ruptured predetermined tearing lines in the withdrawal position. 
     Alternatively, the guide means may also have at least two webs however, which form the aforementioned wall portions and of which each is provided with at least one bending joint in such a way that the webs can be folded together as the penetration element is displaced into the withdrawal position. The webs thus form spider-like legs of the penetration element, which can preferably fold outwardly during the course of the linear movement. 
     Alternative embodiments of the guide means would of course be conceivable. For example, the wall portion could thus also be formed as a bellows, which can be pressed together in the manner of an accordion. A number of interconnected rings or ring segments, which can be pushed together telescopically, would also be conceivable. A considerable advantage is in any case achieved when the guide means are connected in one piece to the head piece and/or to the penetration element. The entire structure can thus be produced in one piece as an injection-molded part in plastic material. In specific cases, it may also be conceivable however due to the fabrication method to produce individual components separately and to then weld or otherwise connect said components to one another. 
     For example, in an embodiment that is possibly likewise to be preferred, the guide means may comprise fastening means, which, in order to connect the guide means to the head piece, can be latched thereto. The latched connection is preferably implemented here in such a way that the two parts are interconnected non-releasably, that is to say are not intended to be released by a user. For example, the fastening means may comprise detent hooks, which engage in corresponding detent recesses on the head piece, where they are then latched. Here, the guide means can be connected for example in one piece to the penetration element or can be connected thereto via further fastening means. Of course, depending on the requirement, other connection types are also conceivable, with which the guide means are connected to the head piece, for example by means of laser welding or ultrasonic welding or also by adhesive bonding however. 
     An embodiment of the penetration element with differently formed head pieces can therefore be used. For example, different head pieces can be matched to different containers, whereas identical penetration elements can be connected to the head pieces by means of the aforementioned fastening means. In addition, different material properties can thus be paired with one another in an optimal manner. Here, materials that can be sterilized by means of different methods (for example that can be sterilized by means of irradiation or steam) without enduring damage during this process are optimal. 
     The head piece may advantageously also be formed in two or more parts, wherein a first part is provided to be coupled to the container and a second part is connected to the penetration element. This results in the advantage that, for example, one embodiment of the second part can be used for different designs of the first part, for example for different containers. The at least two parts are preferably interconnected via latched connections or for example via a welded connection by means of laser or ultrasound or via an adhesive bond. In principle, one-piece embodiments of the head pieces may also be advantageous however. 
     In order to ensure a germ-free and an as air-tight or liquid-tight attachment as possible to the penetration element, said penetration element is provided with a corresponding coupling part. Here, this may be the female taper of a Luer lock for example. Other types of coupling means, such as any snap-fit seals or the like, are also conceivable however. 
     The penetration element may additionally comprise detent means, by means of which it can be latched in the withdrawal position. It is thus ensured that no undesired relative movements occur as the liquid is withdrawn. 
     These detent means are preferably arranged on the penetration element in such a way that they are externally accessible for manipulation by a user. A latched connection can therefore be produced manually as necessary, should this not occur duly automatically for example. In particular, the detent means may be arranged outside the deformable wall portion formed for example as a membrane. The penetration element preferably comprises a fingerplate, which is provided for displacement between an idle position and withdrawal position. Here, the fingerplate forms a support for a user&#39;s finger so as to easily carry out the transition from the idle position into the withdrawal position. The detent means may advantageously be formed on the fingerplate, for example in the form of detent hooks or detent tongues extending towards the head piece. 
     The head piece in this case preferably comprises detent means, which are complementary to the detent means of the penetration element such that the penetration element can be latched by means of its detent means to the head piece. In the withdrawal position, the head piece and penetration element therefore form a well-fixed and robust arrangement. It goes without saying that, in variants, the penetration element can also be latched elsewhere in the withdrawal position, for example directly on the flange of an attached container. A latched connection cannot be controlled as well in this way however, since it is not produced within the device alone. 
     The head piece may carry a centering ring, which additionally guides and centers the hollow needle. The sealing element is thus pierced at a precisely defined point. In addition, undesired transverse movements caused by incorrect handling during the piercing process are avoided. 
     To protect the penetration element in the idle position and also as a security assurance, the penetration element is covered by a releasable protective cap. This protective cap must be sufficiently stable so as to prevent displacement of the penetration element, even under severe impacts and shocks. As a security assurance, the protective cap may comprise a separable guarantee band for example. The protective cap additionally also has the further object of sealing the device in a germ-free manner. This requires the protective cap to be pressed tightly against the sealing element and/or against the container mouth. This can be achieved for example via a sleeve, which is shrunk-fit or pressed on or flange-mounted around the head piece and around the container mouth. With an embodiment of this sleeve for example formed from aluminum or from an aluminum alloy, one end of the sleeve can be cast directly into the head piece during production. Once the container has been filled and sealed, the free end can be pressed on or flange-mounted around the container mouth. 
     The protective cap can particularly advantageously also be provided with a thread and screwed onto the head piece and/or onto the penetration element. The screw cap could be fixed for example via a welded connection. 
     A very advantageous possibility for fastening on a container mouth also lies in snapping the head piece onto the container mouth. With accordingly formed detent means, a relatively high contact pressure can be built up in this case. Comparable snap-fit connections on container mouths are already known for example in the case of seals in the food processing industry. 
     A further very advantageous embodiment lies in the selection of maximally transparent plastics for the individual components. The finished filled and assembled product can therefore be inspected visually for any defects without destruction. 
     It has been found that a plastic having a certain proportion of glass balls or of a glass granulate is particularly advantageous. It has been found that a proportion of 5%-20%, preferably 10%-15%, produces particularly good properties with regard to stability, in particular in the idle position, and also with regard to the fracture or tear behavior of the membrane during the transition into the withdrawal position E. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
       Further advantages and individual features of the invention are presented in the drawings and will be described hereinafter. In the drawings: 
         FIG. 1 : shows a considerably enlarged cross section through a device according to the invention in the idle position, 
         FIG. 2 : shows the device according to  FIG. 1  in the withdrawal position with attached syringe, 
         FIG. 3 : shows a section through the plane I-I according to  FIG. 1 , 
         FIG. 4 : shows a section through the plane II-II according to  FIG. 1 , 
         FIG. 5 : shows a cross section through an alternative exemplary embodiment of a device, 
         FIG. 6 : shows the device according to  FIG. 5  in the withdrawal position, 
         FIG. 7 : shows a further slightly modified exemplary embodiment of the device according to  FIG. 5 , 
         FIG. 8 : shows the device according to  FIG. 7  in the withdrawal position, 
         FIG. 9 : shows a cross section through a device according to the invention with integrated withdrawal valve, and 
         FIG. 10 : shows a cross section through a further exemplary embodiment of a device, 
         FIG. 11 : shows an external oblique view of a further exemplary embodiment of a device in an idle position without head piece, 
         FIG. 12 : shows a further external oblique view of the exemplary embodiment according to  FIG. 11 , 
         FIG. 13 : shows a detailed view of a hollow needle of the exemplary embodiment according to  FIG. 11 , 
         FIG. 14 : shows an external side view of the exemplary embodiment according to  FIG. 11 , 
         FIG. 15 : shows an external side view of a head piece for the device in  FIG. 11 , 
         FIG. 16 : shows a plan view of the head piece according to  FIG. 15 , 
         FIG. 17 : shows a longitudinal section through the head piece according to  FIG. 15 , 
         FIG. 18 : shows a further longitudinal section through the head piece according to  FIG. 15 , 
         FIG. 19 : shows a longitudinal section through a further embodiment of a two-part head piece for a device according to the invention, 
         FIG. 20 : shows an external oblique view of a coupling part of the head piece according to  FIG. 19 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows an arrangement consisting of a device  1  according to the invention, which is fitted onto the container mouth  20  of a container  3 . The container  3  is fabricated for example from glass, is filled with a liquid  2 , and is sealed in an airtight manner by means of a sealing element  4 , for example made of rubber. The liquid  2  may be a pharmaceutical active ingredient, which is intended to be injected by means of an injection syringe either directly into the human or animal body or to be admixed with an infusion system. 
     The device  1  consists substantially of a head piece  5  made of plastic material, which rests tightly via its underside on the outer edge region of the sealing element  4  and which is connected via a membrane  7  curved in a dome-like manner to a central penetration element  6 . The head piece  5  is connected in one piece to a wall portion  22 , which is used as a support for an externally arranged guarantee band  21 . The sealing and interlocked connection of the head piece  5  to the container mouth  20  is achieved via a sleeve  19  made of aluminum, which is cast directly into the head piece  5  and which is pressed at its free end onto the container mouth  20 . In a plane immediately above the sealing element  4 , the head piece carries a centering ring  17 , which has a central opening  30  and which for example can be snapped into place. 
     The preferably rotationally symmetrical penetration element  6  has, in the central portion, a circumferential collar  12 , in which aspiration openings  23  are arranged ( FIG. 3 ). A microbiologically tight filter  11 , which covers all aspiration openings  23 , is arranged beneath the collar. The female taper of a Luer lock  14  is arranged integrally above the collar  12 . Said female taper transitions directly into a hollow needle  9 , which extends downwardly beneath the collar  12  and which opens out into a piercing tip  31  provided with openings. The term “hollow needle” is used here for any element that forms an aspiration channel and that is able to penetrate the sealing element  4 . 
     As can also be seen in particular from  FIG. 4 , the hollow needle  9  has a relatively thick wall, along which aeration channels  10  in the form of grooves are preferably arranged in parallel. These grooves extend until directly below the collar  12 . The entire penetration element  6  is preferably formed in one piece, apart from the filter  11 . It can be welded or snapped into the membrane  7 , or it may likewise even be formed in one piece therewith. The aeration channels can also be formed in cross section in the manner of a dovetail groove. The risk of the resilient material of the sealing element  4  sealing the aeration channels can thus be reduced. 
     The membrane  7  is resilient, such that it biases the penetration element  6  upwardly in the illustrated idle position R. In this idle position, the penetration element is covered by a protective cap  18 , which is connected via a predetermined breaking line  24  to the guarantee band  21 . A ring seal  32  between the wall portion  22  and the protective cap  18  ensures that the entire interior of the protective cap is sealed hermetically and in a sterile manner above the sealing element  4 . The protective cap  18  can be fabricated from plastic material or also from aluminum. In specific cases, it would be conceivable for the Luer lock  14  to be held or centered in the idle position R by the protective cap  18 . 
     The withdrawal of the liquid from the container  3  in the withdrawal position E will be explained hereinafter with reference to  FIG. 2 . Before the withdrawal position is reached, the protective cap  18  has to first be removed such that only the guarantee band  21  still remains on the head piece  5 . Depending on the guarantee system, the guarantee band could also be removed when opening the protective cap. Immediately once the protective cap has been removed, the male taper  26  of a syringe  25  is introduced into the Luer lock  14  and a force is exerted onto the penetration element  6  in the arrow direction k. In so doing, the hollow needle  9  penetrates the sealing element  4 , such that the piercing tip  31  protrudes into the interior of the container  3 . Here, the aeration channels  10  additionally create a connection between the interior of the container  3  and the inner face of the membrane  7 . 
     In the withdrawal position E, the membrane  7  is curved severely in the direction of the sealing element in such a way that the spring bias changes the direction of force and fixes the penetration element in the withdrawal position. The friction between the hollow needle  9  and the sealing element  4  also contributes to the fact that the penetration element remains in this position. 
     The liquid is actually withdrawn by drawing the syringe  25 , not of course in the illustrated position, but with the head arranged upwardly, such that the liquid floods the inner face of the sealing element  4 . By drawing the syringe, the liquid thus flows in the arrow direction f through the hollow needle  9  into the syringe  25 . The negative pressure produced during this process above the liquid level is counterbalanced by air aspirated from the atmosphere, which reaches the container  3  in the arrow direction  1  via the intake openings  23 , through the filter  11  and via the aeration channels  10 . A contamination of the liquid is not possible here, because dirt particles or for example also bacteria are filtered out at the filter  11 . 
     An alternative exemplary embodiment of a device is illustrated in  FIGS. 5 and 6 , wherein identical components are provided with reference signs identical to those used in the exemplary embodiment according to  FIGS. 1 and 2 . The main difference lies on the one hand in the connection between the head piece  5  and the penetration element  6  and on the other hand in the arrangement of the filter  11 . The sealing cap  18  is designed slightly differently and is not provided with a separate guarantee band. Rather, the predetermined breaking line  24  is located directly above the cast-in upper edge of the sleeve  19 . 
     The head piece  5  is connected to the penetration element  6  via four material webs  8 , which are distributed uniformly around the hollow needle  9 . Each material web has at least one bending joint  33 . The material webs  8  thus form spider-leg-like supports, which hold the penetration element  6  in the idle position. The Luer lock  14  is additionally fixed on the base of the sealing cap  18 . 
     In the present exemplary embodiment, the filter  11  is not fixed on the penetration element, but on the head piece  5 . To this end, a separate filter mount  13  is provided, which has a central opening and which surrounds the hollow needle  9  in an annular manner. The inner, hub-like part of the filter mount rests on the sealing element  4 , wherein the central opening  34  however is connected via grooves  35  to the annular hollow chamber  36 , in which the filter  11  is fixed. An inwardly protruding detent ring  16  is arranged on the filter mount  13 . An outwardly protruding detent ring  15  is also arranged on the penetration element  6 . 
     In the withdrawal position according to  FIG. 6 , the material webs  8  are folded about the bending joints  33  and in so doing protrude slightly outwardly. The detent rings or detent lugs  15  and  16  are latched to one another and thus fix the penetration element, of which the hollow needle  9  has pierced the sealing element  4 . Air from the atmosphere passes through the filter  11  via the grooves  35  and the aeration channels  10  into the interior of the container  3 . 
     The exemplary embodiment according to  FIGS. 7 and 8  differs from that according to  FIGS. 5 and 6  merely by the manner in which the filter  11  is fixed. Here, the filter is not fixed by a separate filter mount, but directly by a portion of the head piece  5 . Here, merely an inner ring  37 , which carries the inwardly protruding detent ring  16 , is formed separately. 
     The exemplary embodiment according to  FIG. 9  corresponds largely to that according to  FIG. 1 . A valve denoted by  38  is incorporated in the special coupling part  39  formed by a valve housing  27 . Said valve makes it possible, in the withdrawal position, to withdraw liquid from the container  3  in a number of chronologically separate sequences, wherein a sterile seal is ensured after each withdrawal. A valve body  28  made of a flexible material is mounted in the valve housing  27 . In this valve body, a slit  29  is arranged, which is closed in the idle state such that the valve body  28  acts as a seal. When a syringe is fitted into the Luer lock  39 , the slit  29  is spread open and thus releases the access to the hollow needle  9 . A valve of this type is described for example in WO 03/064907. Due to the greater overall height of the penetration element  6 , the sealing cap  18  must of course also be longer. 
     The exemplary embodiment according to  FIG. 10  indeed has a certain similarity to that according to  FIG. 1 , but differs therefrom by the design of the membrane  7 , the arrangement of the filter  11 , and also the type of fastening on the container mouth  20 . In addition, the penetration element  6  is fixed in the withdrawal position by a detent connection. The membrane  7  curved in a dome-like manner is provided with predetermined breaking points or predetermined breaking lines  40  distributed over the circumference, which extend approximately parallel with respect to the longitudinal center axis from the zenith of the dome as far as the lower edge thereof. These predetermined breaking points can be formed here as weakened lines or may also be perforations. As the penetration element is transferred from the illustrated idle position into the withdrawal position (similarly to  FIG. 2 ), the predetermined breaking points  40  rupture, thus producing slit-like openings. In the withdrawal position, detent blocks  42  arranged on the penetration element latch into the detent hooks  41  on the head piece  5  and thus fix the withdrawal position. The detent blocks can be designed rather differently, and, for example as illustrated in the left-hand half of the image, may be arranged rigidly on the penetration element. An arrangement on the membrane  7 , as illustrated in the right-hand half of the image ( 42 ′), is also conceivable however, wherein each detent block carries out a pivoting movement of approximately 90° until reaching the corresponding detent hooks  41 . 
     The head piece  5  is not fixed here on the container mouth by means of a sleeve, but is snapped thereonto with the aid of a snap-fit collar  43 . This snap-fit collar is dimensioned in such a way that a sealing pressure is exerted onto the sealing element  4  and a removal of the protective cap  18  is also possible without the head piece  5  being lifted accidentally from the container  3 . 
     The filter  11  is assigned here to the head piece  5 , wherein it is fastened directly beneath a carrier plate  44  provided with intake openings  23 . The flowing air thus flows via the opened predetermined breaking points  40 , through the intake openings  23  and the filter  11  and then via the aeration channels  10  into the interior of the container  3 . 
     In the case of the present exemplary embodiment, the protective cap  18  with the predetermined breaking line  24  is also designed in a slightly modified manner. The dome-like membrane  7  transitions at its lower edge into a circumferential support ring  45 , which for example is connected in one piece to the head piece  5  by means of a welded connection. A seal  32 , which hermetically seals the inner face of the protective cap  18  outwardly, is supported on said support ring. The ring seal  32  could also be integrated as a bi-component injection-molded part directly into the protective cap  18 . The material strip beneath the predetermined breaking line  24  is designed as a guarantee band, after the removal of which the protective cap  18  can be lifted from the support ring  45 . 
       FIGS. 11 to 14  show various views of an alternative exemplary embodiment of a penetration element  6  of a device according to the invention and are described together hereinafter. Here, identical components are provided with reference signs identical to those used in the exemplary embodiments according to the previous figures. The exemplary embodiment in  FIGS. 11 and 12  (and also  13  and  14 ) corresponds in large parts to the device illustrated in  FIG. 10 . A significant difference lies in the design of the membrane  7 , which is provided for connection of the penetration element  6  to the head piece  5 , and also in the design of detent elements for latching the penetration element  6  to the head piece  5  in the withdrawal position. 
     The membrane  7  is likewise formed in a dome-like manner and transitions at the edge via a support ring  45  into a fastening ring  56 , which is provided to fasten the membrane  7  on the head piece  5 . To this end, the support ring  45  has four detent hook pairs  54 , which are arranged on the end face and are provided for latching into corresponding recesses  63  of the head piece  5  (see  FIGS. 15-18 ). 
     The membrane  7  has four substantially circular flattened portions  50 , which for example may be defined by a predetermined breaking point. On the inner wall, the membrane  7  has four perforation webs  51 , which are arranged substantially in the longitudinal direction between the circular flattened portions  50 . The perforation webs  51  are stiff and are connected rigidly to the support ring  45  and also to the fastening ring  56 . As the penetration element  6  transitions into the withdrawal position E, the perforation webs  51  tear or perforate the membrane  7 . It is thus ensured that external air can be fed to the aeration channels  10  of the hollow needle  9  of the perforation element  6 . 
     A substantially circular cylindrical neck  52  of the penetration element  6  adjoins the membrane  7  and extends outside the membrane  7  in the longitudinal direction. At the end, the neck  52  transitions into the Luer lock  14 . A fingerplate  53  projects in a flange-like manner between the neck  52  and Luer lock  14 , transversely with respect to the longitudinal direction of the penetration element  6 . Here, an area of the fingerplate  53  is larger than an outline of the membrane  7 , such that, in a plan view in the longitudinal direction, the overall membrane  7  with support ring  45  and fastening ring  56  is covered by the fingerplate  53 . 
     The Luer lock  14  is connected via a fluid channel in the neck  52  to a withdrawal channel  9 . 1  of the hollow needle  9  of the penetration element  6 , said hollow needle being arranged centrally within the membrane  7 . Here, the hollow needle  9  has two aeration channels  10  in the form of V-shaped longitudinal grooves, which are arranged on the outer face of the hollow needle  9  in a mutually opposed manner with respect to the longitudinal axis. Here, the withdrawal channel  9 . 1  of the hollow needle  9  is arranged off-center, such that a piercing tip  31  can be formed solidly for good penetration ability (see also  FIG. 13 ). 
     Two detent tongues  55  arranged in a mutually opposed manner with respect to the longitudinal direction are formed on the fingerplate  53  in a manner extending in the longitudinal direction towards the membrane  7 . Here, the detent tongues  55  are used to latch the penetration element  6  in the withdrawal position E in corresponding recesses  65  on the head piece  5  (see  FIGS. 15 to 18 ). The detent tongues  55  (with respective recesses on the head piece  5 ) therefore perform a similar function to, for example, the detent blocks  42  and  42 ′ and detent hooks  41  in  FIG. 10 . In contrast thereto, the detent tongues  55  are arranged outside the membrane  7  however. This has the advantage inter alia that correct latching of the penetration element  6  on the head piece  5  can also be monitored externally, or, for example should engagement not be achieved correctly, the engagement can be produced manually. 
     The penetration element  6  is preferably injection-molded with the membrane and the other elements illustrated in  FIGS. 11 to 14  as a one-piece molded part made of plastic. Of course multi-part embodiments are also conceivable. 
       FIGS. 15 to 18  show a head piece  5  provided for the penetration element  6  in  FIGS. 11-14  and are described together hereinafter. Here, identical components are provided with reference signs identical to those used in the exemplary embodiments according to the previous figures. 
     The head piece  5  has a largely circular cylindrical form with a receiving region  60  for arrangement of the container mouth  20  of the container  3 . In the receiving region  60 , the snap-fit collar  43  is formed on the inner wall and has four inwardly protruding detent protrusions. In the longitudinal direction, the receiving region  60  is defined with respect to a fastening region  62  for the penetration element  6  via an intermediate wall  61  arranged transversely with respect to the longitudinal direction of the head piece  5 . The intermediate wall  61  has a central opening  30 , which is used for the passage and for the guidance of the hollow needle  9  of the penetration element  6  when said needle is fastened via the membrane  7  to the head piece  5  and is brought into the withdrawal position E. 
     The intermediate wall  61  additionally has detent recesses  63  for the detent hook pairs  54  of the membrane  7 . The recesses  63  are arranged here in an annular manner in an annular receiving indentation  64  for the fastening ring  56  of the membrane  7 . 
     In the fastening region  62 , detent recesses  65 , which are outwardly open in the radial direction, are formed on the lateral surface and are provided for engagement of the detent tongues  55  of the penetration element  6  when said penetration element is located in the withdrawal position E. Since four detent recesses  65  are provided, the penetration element  6  can be inserted in different orientations into the head piece  5 , wherein a latching of the detent tongues  55  in each orientation is ensured. 
     A receiving region  66  for the filter  11  is formed on the intermediate wall  61  on the side of the receiving space. A circumferential sealing edge  67  of the receiving region  66  is formed in such a way that it rests tightly on the sealing element  4  when the head piece  5  is fitted onto the container  3 . The intake openings  23 , which connect the fastening region  62  to the receiving region  60 , are formed in the intermediate wall  61  in the region of the receiving region  66 . If the filter  11  is arranged in the receiving region  66 , external air can be aspirated through the intake openings  23  via the filter  11  and fed through the aeration channels  10  of the hollow needle  9  to the interior of the container  3 . 
       FIGS. 19 and 20  show a further embodiment of the head piece  5  provided for the penetration element  6  in  FIGS. 11 to 14  and are described together hereinafter. Here, identical components are provided with reference signs identical to those used in the exemplary embodiments according to the previous figures. 
     In contrast to the embodiment in  FIGS. 15 to 18 , the head piece  5  in  FIGS. 19 to 20  is formed in two parts, wherein a tubular connection part  71  has a largely circular cylindrical form. An interior of the connection part  71  forms the receiving region  60  for arrangement of the container mouth  20  of the container  3 . Similarly to the embodiments in  FIGS. 15 to 18 , the snap-fit collar  43 , which comprises four inwardly protruding detent protrusions, is formed in the receiving region  60  on the inner wall. 
     The connection part  71  is sealed on one side by a coupling part  70 , which comprises the intermediate wall arranged transversely with respect to the longitudinal direction of the head piece  5 . The coupling part  70  has a circular cylindrical wall  72 , which protrudes outwardly in the longitudinal direction and surrounds the fastening region  62  for the penetration element  6  or the membrane  7 . 
     The coupling part  70  is connected via the intermediate wall  61  to the connection part  71 , said intermediate wall sealing the connection part  71  in the manner of a cover. Here, the intermediate wall  61  can be connected in an interlocked or force-locked manner and/or can be integrally bonded to the connection part  71 . Similarly to the embodiment in  FIGS. 15 to 18 , the intermediate wall  61  comprises the detent recesses  63  for the detent hook pairs  54  of the membrane  7  and also the central opening  30 , which is used for the passage and for the guidance of the hollow needle  9  of the penetration element  6 . 
     The detent recesses  65 , which are provided for engagement of the detent tongues  55  of the penetration element  6 , are formed in the embodiment in  FIGS. 19 and 20  in the circular cylindrical wall  72  of the coupling part  70 . The receiving region  66  for the filter  11  is formed on the intermediate wall  61  on the side of the receiving space. In contrast to the embodiment in  FIGS. 15 to 18 , the sealing edge  67  is distanced radially outwardly from an edge of the recess  66 . The intermediate wall  61  additionally comprises on the side of the receiving space a multiplicity of detent wedges  68 , which are arranged radially and prevent a rotation of the container  3  relative to the detent plate  61  due to engagement into the sealing element  4 , which for example is resilient. It goes without saying that detent wedges of this type may also be provided in all other embodiments of a head piece. 
     The head piece in  FIGS. 19 and 20  is provided in particular for the attachment to containers having a 20 mm flange. 
     For all embodiments according to the invention, PET films or polycarbonate films, which are penetrated by the finest of openings, can advantageously be used for example as a filter besides the conventional microfilter membranes. Instead of separately inserted or adhered filters, these could also be integrated directly during injection molding of the respective bearing constructions. A significant advantage of all variants according to the invention also lies in the fact that these can be used for containers having a flange of 13 mm or 20 mm diameter or for containers having flanges of any diameter. In particular, it goes without saying that each embodiment can be adapted accordingly.