Abstract:
A valve ( 20 ) comprises a housing body ( 22 ) with a discharge channel ( 34 ), whereby an elastically-deformable membrane ( 24 ) is provided in the housing body which seals off the discharge channel. The membrane is sealed at the front end thereof and is arched to form a dome.

Description:
BACKGROUND OF THE INVENTION 
   The invention relates to a valve for the application of liquid health care products or of health care products dissolved in liquids, in particular of eye drops. 
   Dropper systems for drop application are known as components of medication packagings in a variety of embodiments. It is disadvantageous with the hitherto known dropper systems that, after a first use, contamination of the liquid to be applied cannot be effectively prevented since, when the screw cap has been removed, germs can enter into the health care product supply through the discharge passage. For this reason, preservatives have hitherto been added to the health care product which are intended to prevent the contamination of the health care product over a limited discharge period. Such preservatives can, however, cause allergic reactions in the user such that it is desirable to omit such additives. 
   SUMMARY OF THE INVENTION 
   It is an object of the present invention to provide a simple valve for the application of a health care product which also effectively prevents contamination of the liquid medication after a first use. 
   The possibility is provided with the valve in accordance with the invention to discharge the liquid to be applied through a sealed passage. The valve in accordance with the invention simultaneously consists of only two functional components, namely the take-up body and the membrane. 
   To prevent the access of micro-organisms into the medication supply, the discharge passage, and also an optional aeration passage, can be closed impermeable to germs with the help of the elastically deformable membrane. The discharge passage is only opened by the membrane at the moment of the product removal and the discharge passage is closed impermeable to germs again subsequent to the product removal. 
   In the event that the product quantity propelled out on the removal should be replaced by ambient air in order to avoid underpressure in the container, this air can be subsequently guided in through an aeration passage likewise closed by the elastic membrane. In this process, contamination of the container content is particularly effectively prevented if a sterile filter is provided in front of the orifice of the aeration passage in the take-up body so that the ambient air must first pass through the sterile filter before it can subsequently flow into the container. 
   In accordance with an advantageous embodiment, the front end of the membrane projects out of the take-up body such that the front end of the membrane can be used simultaneously as an elastic, and thus soft, application tip. 
   It is also advantageous for the membrane to be closed and/or arched in dome-shape at its front end. In this manner, a drop release is promoted and injuries in the region of the application area, in particular eye injuries, are precluded. 
   In accordance with a further advantageous embodiment, the membrane and the take-up body contact one another in a sealing manner along a contact section, with the contact section in particular being able to be made as a paraboloid of revolution. Such a shape has proved to be advantageous with respect to a safe opening and closing in the region of the contact section. 
   The membrane is preferably made as a hollow element open at one end such that good elasticity and thus good closing and sealing properties are ensured with a low material effort. 
   In accordance with a further advantageous embodiment, the membrane is rotationally symmetrical, and a support element which pre-stresses the membrane in the axial direction is arranged in the interior of the membrane. Such a support element can contribute to sealingly pressing the membrane against the contact section of the take-up body, with a release of the membrane from the take-up body nevertheless taking place against the pre-stressing force on application of the discharge pressure. 
   An embodiment which can be manufactured particularly easily and so cost-favorably is provided when the valve only consists of three functional components, namely the take-up body, the membrane and the support element. The only components which are still required, apart from the container, are a covering cap and an optional sterile filter. These components are, however, not components of the valve necessary for the function. 
   In a further advantageous embodiment of the invention, a plurality of ring passages are provided in the valve and communicate with one another via overflow passages. For example, a first ring passage can be provided between the support element and the membrane, and a second ring passage can be provided between the take-up body and the membrane, with the ring passages communicating with one another via an overflow passage in the membrane. In this embodiment, the liquid to be discharged is first transported into a ring space between the support element and the membrane and is subsequently transported into a ring space between the membrane and the take-up body. When the discharge pressure is increased, the liquid can then be transported from the second ring passage through the contact section in the direction of an outflow passage at the front end of the membrane or of the take-up body. 
   A particularly easy assembly of the valve is provided when the support element in the interior of the membrane is in engagement with the membrane via a latching means, for example via a peripheral latching lip. In this manner, the membrane only has to be pulled over the support element and latched, whereby these two components are already joined together. A simple assembly of this component pre-assembled in this manner can take place in that the support element is inserted into the take-up body with the membrane placed on and is secured in the take-up body via a further latching means. A fully functional valve is hereby provided with only two assembly steps. 
   The support element preferably extends at its rear end over the total internal cross-section of the take-up body, with a throughflow opening being able to be provided for the liquid to be discharged in this region. A secure holding of the support element and of the membrane is ensured in this manner. 
   The valve in accordance with the invention is also suitable for a container which is elastically deformable at least regionally, for example for a squeezy bottle. However, the possibility generally also exists of using the valve for rigid containers. In this case, the propelling-out pressure must be produced in another manner. 
   The present invention will be described in the following purely by way of example with reference to an advantageous embodiment and to the enclosed drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cross-sectional view of a valve secured in a container; 
       FIG. 2  is an enlarged representation of the valve of  FIG. 1  during a product discharge; and 
       FIG. 3  shows the valve of  FIG. 2  during the pressure compensation. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  shows, in cross-section, a container  10  in the form of a squeezy bottle in whose bottle neck a valve  20  is sealingly inserted via a pressing connection  12 . The valve  20  consists of three functional components, namely of a take-up body  22 , of an elastically deformable membrane  24  and of a support element  26 . 
     FIG. 2  shows an enlarged cross-sectional view of the valve  20 . As can be recognized, the take-up body  22  is rotationally symmetrical and consists of a one-piece plastic component which tapers conically in the upper third. A ring-shaped projection  26  is shaped approximately in the middle of the take-up body  22 , with a ring-shaped groove, into which a sterile filter  28  has been inserted, being provided in the projection  26 . The sterile filter is in communication with the ambient air at its lower end face  30 , at the one end. At the other end, the air flowing through the sterile filter  28  can enter into the interior of the intake body  22  via an aeration passage  32 . Furthermore, a ring-shaped indentation  38  is provided in the region of the aeration passage  32  at the inner periphery of the take-up body  22 . 
   The take-up body  22  is hollow at its interior and, starting from its lower end, has a hollow cylindrical section which tapers in the upper third in accordance with the outer contour of the take-up body. A discharge passage  34 , through which the liquid to be applied can be discharged, is furthermore provided in the region of the front end of the take-up body  22 . 
   The membrane  24  which is inserted into the interior of the take-up body  22  and which is made of an elastomer is a one-piece, rotationally symmetrical component which is elongate, hollow in the interior and closed at its front end. The membrane  24  is arched in a dome-shape to form an approximately semi-spherical dome  36  in the region of the closed front end, with the dome  36  of the membrane  24  projecting out of the take-up body  22 . 
   At its lower end, the membrane  24  is formed in hollow cylindrical manner in the region of the indentation  38  and sealingly covers the indentation  38 . 
   A further indentation  40 , into which a complementary formed latching section of the membrane  24  latchingly engages, is provided above the indentation  38  at the inner periphery of the take-up body  22 . 
   In the normal state (cf.  FIG. 1 ), the membrane  24  in the region of the discharge passage  34  sealingly contacts the internal periphery of the take-up body  22  in the region of a contact section  42 . In the region of this contact section  42 , the inner jacket surface of the discharge passage  34  is designed as a paraboloid of revolution, with the membrane  24  having the same outer contour of a paraboloid of revolution at its outer periphery in this section. A discontinuous transition is provided between the outer contour of a paraboloid of revolution of the membrane  24  and the dome  36  at the upper end of the discharge passage  34  in the region of the dome  36 , whereby a discharge passage  44  is formed. 
   The support body  26 , which is likewise a rotationally symmetrical component made in one piece from plastic, is inserted into the interior of the membrane  24 . The support element  26  serves, on the one hand, to pre-stress the membrane  24  axially in the region of the contact section  42  and, on the other hand, to hold the membrane in the take-up body  22 . For this purpose, the support element is provided at its lower end with a ring-shaped projection  46  which can be latched into a correspondingly desired ring groove in the interior of the take-up body  22 . At its upper end, the support element extends up to and into the base region of the dome  36 . It is there received in a hollow cylindrical recess  48  at the inner front end of the membrane  24 . 
   In the region of the contact section  42 , the support element  26  is made in pin-shape, with the outer contour of the pin-shaped section likewise being made as a paraboloid of revolution. However, as the Figures show, there is a clear spacing between the outer jacket surface of the pin-shaped section of the pin element  26  and the inner peripheral area of the membrane  24  in this section which makes it possible for the membrane to deform inwardly in the direction of the support element  26  (cf.  FIG. 2 ). 
   The support element  26  is provided approximately at the middle at its outer periphery with a peripheral latching lip  50  which latchingly engages into a complementary formed, ring-shaped latching recess at the inner periphery of the membrane  24 . The membrane is hereby lightly tensioned axially between the base of the dome  36  and the latching lip  50 . 
   As  FIG. 1  shows, the membrane  24  with the support element  26  is inserted into the take-up body  22  such that, when the support element  26  is latched and when the membrane  24  is latched, the membrane contacts the inner periphery of the take-up body areally and. sealingly along the contact section  42 . A ring passage  52  ( FIG. 2 ), which is preceded by at least one axial overflow passage  54 , is formed in the take-up body  22  at the inner orifice of the contact section  42 , the overflow passage in turn being preceded by a further ring passage  56 . Both the ring passage  52  as well as the overflow passage  54  and the ring passage  56  are bounded at the outer periphery by the take-up body  22  and at the inner periphery by the membrane  24 . 
   As in particular  FIG. 2  shows, a plurality of axial overflow passages  58  are provided in the membrane  24  and connect the interior of the membrane  24  to the outer side of the membrane. Liquid can hereby flow from the interior of the take-up body  22  into the ring passage  56 . 
   The support element  26  furthermore has a plurality of throughflow openings  60  at its lower side which are distributed over the periphery of the support element  26  and which extend in the axial direction. 
   The function of the valve shown in  FIGS. 1 to 3  is as follows: 
   In the state of rest, the membrane  24  of the valve  20  is in the position shown in  FIG. 1  in which the membrane  24  closes both the discharge passage  34  ( FIG. 2 ) and the aeration passage  32  in an outwardly sealed manner such that no liquid can flow out of the interior of the container  10  and no contaminated air can penetrate into the interior of the container  10 . 
   A desired discharge pressure is applied for the discharge of liquid from the container  10 , for example by squeezing the at least regionally elastically deformable container  10 . Overpressure is hereby produced in the interior of the container  10  which propels out the liquid located in the container  10  through the discharge passage  34  (cf.  FIG. 2 ). In this process, the liquid initially flows into the interior of the take-up body  22 , from there through the throughflow openings  60  into the interior of the membrane  24  and from there through the overflow passages  58  into the ring passage  56 . From there, the liquid enters into the ring passage  52  through the overflow passage  54 , with the pressure exerted on the membrane  24  by the liquid raising the membrane from the take-up body  22  inwardly in the direction of the support element  26  such that a ring gap, as is shown in  FIG. 2 , is created between the membrane  24  and the take-up body  22 . Subsequently, the liquid enters into the outflow passage  44  and collects as drops at the dome  36  such that an application of the drop is possible, for example in the eye of a user. 
     FIG. 3  shows the state of the membrane  24  after the discharge pressure has been reduced. The overpressure in the interior of the container  10  is hereby reduced and the restoring forces of the pre-stressed elastic membrane  24  have the effect that it again firmly contacts the inner jacket surface of the contact region  42  of the take-up body  22  such that the discharge passage  34  is again sealingly closed. 
   The underpressure created in the container  10 , which is produced by the discharge of the liquid, subsequently has the effect that the lower marginal region of the membrane  24 , which has previously sealingly closed the aeration passage  32  or the indentation  38 , rises from the inner periphery of the intake body  22 , as is represented in  FIG. 3 . Ambient air can hereby subsequently flow into the interior of the container  10  via the sterile filter  28  and the aeration passage  32  and the indentation  38  until pressure compensation has been achieved between the ambient pressure and the internal container pressure. The corresponding air flow is indicated by arrows in  FIG. 3 . 
   If the valve is used in a dropper system which does not require any pressure compensation, the aeration passage  32  and the sterile filter  28  can be omitted.