Patent Publication Number: US-9415925-B2

Title: Metering device

Description:
The invention relates to a metering device for metered dispensing of a fluid, in which a storage container is connected to a metering head, a spindle being guided in the metering head and having a through-channel for the fluid to be transported. 
     Numerous metering devices for metered dispensing of a fluid are known in the state of the art. 
     Thus, e.g. in EP 0 473 892 A2, a fluid dispensing device for a sterile fluid is described, in which a storage container is connected to an actuation button and a piston-cylinder system is provided for transporting the fluid. In the case of such fluid dispensing devices, achieving adequate sealing is thereby problematic. Sealing of such a fluid dispensing device is important in particular for achieving a sterile system for sensitive fluids. Such fluid dispensing devices with a piston-cylinder system also have the disadvantage that the quantity to be conveyed cannot always be determined exactly. Such fluid dispensing devices, as are described in EP 0 473 892 A2, also present difficulties if eye drops are intended to be used as sterile fluid. For this application case, it is in fact important that a so-called “oligodynamic effect” is exploited. Producing such an oligodynamic effect is likewise not simple with piston-cylinder systems. 
     Starting herefrom, it is therefore the object of the present invention to propose a metering device in which, on the one hand, a high degree of sealing is achieved so that sterile administration of the fluid is possible and so that, with this system, an oligodynamic effect can be achieved in addition. 
     This object is achieved by a metering device having a feature combination according to patent claim  1 . The sub-claims reveal advantageous developments. 
     According to the invention, a metering device according to patent claim  1  is hence proposed, in which, in the operating state, a storage container is connected to a metering head, a spindle being guided in the metering head and having a through-channel which connects the outlet- and the inlet valve. 
     As a result of the configuration according to the invention of a spindle system instead of a piston-cylinder system, it has now been shown surprisingly that an extremely high degree of sealing of the system can consequently be achieved. As a result, a sterile and reliable metering of fluids is possible. The configuration according to the invention has the advantage in addition that the outlet valve can be configured in various ways due to the above-described design so that e.g. also a ball valve inter alia can be used. The advantage associated with using a ball valve is that the latter can be configured for example as a silver-coated metal ball so that an oligodynamic effect can hence be exerted. A further advantage of the metering device according to the invention resides in the fact that reliable metering, also precise from the point of view of volume, of the fluid to be administered can be achieved. The metering device according to the invention hence offers a high degree of sterility and operating reliability due to the novel spindle system. 
     Advantageously, the metering device according to the invention is thereby constructed such that the spindle is guided in the metering head and pump housing, the spindle which is configured as a cylindrical component having a central boring which then forms the through-channel. The advantage of such a construction resides in the fact that an optimal connection between the outlet and the inlet valve can consequently be produced. Preferably, the through-channel is thereby constructed then such that it is widened in the direction of the inlet valve. It is consequently achieved that the fluid to be suctioned in can be conveyed optimally into the through-channel in cooperation with the inlet valve. A further substantial element of the device according to the invention resides in the fact that the through-channel in the case of the spindle is then dimensioned in the direction of the outlet valve such that the outlet valve can engage in the through-channel. The through-channel is hence dimensioned and configured on the outlet side such that it cooperates then together with the outlet valve which can be configured in various ways in order to achieve optimum sealing. The through-channel should thereby preferably have a small length in order that a small residual volume can be achieved. 
     In the case of the metering device according to the invention, there can be disposed obviously in the storage container itself, as is already known for example in the state of the art, e.g. bellows or a foil bag. The bellows and the inner- or foil bag strive to return to their original position because of their intrinsic material thickness, as a result of which a suction force is produced which enables further improved sealing. 
     Preferably, the storage container is thereby a cylindrical container and the opening is disposed in a tapered region which is configured as a neck. In particular this embodiment of the storage container is preferred. The configuration of the neck is favourable such that then a locking connection can be disposed on the neck, on the outside, for connection of the metering head to the pump housing. In this embodiment, the locking connection hence connects the storage container to the pump housing and to the metering head. In the metering head, preferably a spring or bellows, preferably with an integrated sealing function, is/are thereby disposed between the inside of the metering head and the locking connection. As springs, preferably springs made of metal can hereby be used. 
     Furthermore, it has proved to be advantageous if the locking connection is connected via a first gasket to the opening of the storage container in order to improve the sealing. This first gasket is thereby disposed preferably on the end-side of the neck and can hence serve for sealing the locking connection to the pump housing. A further improvement can also be achieved if a second gasket, and in fact between the locking connection and the spindle, is provided in the interior of the pump housing. The spindle is then guided through this gasket. 
     As already explained initially, a great advantage of the metering device according to the invention resides in the fact that great variability with respect to the inlet- and outlet valve is possible because of the spindle system. Thus, for example the inlet valve, which is disposed on the pump housing in the interior in the direction of the container, can be configured in the form of a ball valve which is known per se in the state of the art or else a plastic material valve is used as inlet valve. The ball valve is thereby constructed as known per se in the state of the art, i.e. a ball is disposed in a valve seat and is conveyed as a result of the different pressure ratios such that the inlet opening is closed or open. If a ball valve is used, it can thereby be constructed such that it consists of two circular segments and the inner circular segment is lifted out of the circle plane by actuation of the spindle. As a result, opening is effected and in the converse case, also closing. 
     Various embodiments are also possible with respect to the outlet valve. Thus the outlet valve can also be configured in the form of a ball valve. In this case, the valve seat is then configured in the spindle itself. The ball and the spring which cooperate are disposed at the suitable position in the metering device and then cooperate with the valve seat. 
     Another possibility for configuring the outlet valve exists such that, instead of a ball, bellows or a valve piston are/is provided. Bellows-like springs which together with a plastic material cone form the outlet valve can be provided. Finally, the outlet valve can also be formed by a specially configured cone, the cone itself then having an outlet opening. This cone then cooperates, again as known in the case of a valve, with a ball and a spring. 
     In order to produce an oligodynamic effect, the balls which are provided in the valves can of course be coated with silver. Also ceramic balls, steel balls, glass balls or silver-copper balls can be used. In the case of the springs which are in operational connection with the balls, metal springs or even metal springs coated with plastic material or even plastic material springs can be used. 
     In the case of the metering device according to the invention, as already described initially, bellows or a plastic material- or a foil bag can be provided for storing the fluid. The bellows, as known per se from the state of the art, can thereby also have a drag piston. It is also preferred in the case of the metering device according to the invention if the bellows have a contact device at at least one fold which is in contact with the inside of the storage container. As a result, it can be achieved that, with the contact device, optimum sliding of the bellows via the contact device with the inside of the storage container is ensured. Likewise, it is consequently made possible that the bellows or the inner bag maintain/maintains the original position thereof. 
     From the point of view of choice of material, basically all materials which are known to the person skilled in the art can be used both for the bellows and for the foil bag. Preferred materials are polyamide (PA), polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE) and/or polyurethane (PU). In order to improve the oligodynamic effect, the metering head itself can also be selected from the above-mentioned materials, then in addition also an additive, and in fact preferably silver here, can be jointly incorporated. This additive will then come in contact with silver during actuation, i.e. when the fluid passes through the outlet opening, so that an oligodynamic effect can be achieved. 
     The metering device according to the invention can be used in particular for fluid or semi-solid contents, such as e.g. gels, ointments or creams. 
     The metering device according to the invention is described in more detail by means of the subsequent  FIGS. 1 to 6 . 
    
    
     
         FIG. 1  shows a first variant of a metering device according to the invention with bellows. 
         FIG. 2  shows a second variant of a metering device according to the invention with an inner bag. 
         FIG. 3  shows a third variant of a metering device according to the invention with two ball valves and inner bags. 
         FIG. 4  shows a fourth variant of a metering device according to the invention. 
         FIG. 5  shows variants according to the invention of an outlet valve. 
         FIG. 6  shows a further variant of an outlet valve according to the invention. 
         FIG. 7  shows further variants according to the invention of an outlet valve. 
         FIG. 8  shows a further embodiment with bellows in the metering head and a valve piston in the outlet valve. 
     
    
    
     In  FIG. 1 , a first metering device according to the invention is illustrated,  FIG. 1 a    showing the metering device when the metering head is pressed, whilst  FIG. 1 b    shows the metering device in the retracted position, i.e. when relaxing. 
       FIG. 1  shows a metering device  1  which has a storage container  2  with a base  3 . Bellows  11  are disposed in the storage container  2 . An opening  4  into which a metering head  5  is inserted is disposed on the side situated opposite the base. The metering head thereby has a pump housing  6 , an inlet valve  7  which protrudes into the storage container  2  and also an outlet valve  9 . The inlet valve  7  is connected to the outlet valve  9  via a through-channel  10  which is disposed in a spindle  8 . 
     The outlet valve  9  is illustrated in addition in enlarged representation, the metering head  5  having an opening  16  and a ball  17  which serves for closure of the through-channel  10  with the help of a spring  18  being disposed in the inside of the metering head. 
     Likewise, the closing mechanism of the inlet valve  7 , in the form of a plastic material valve, is illustrated in enlarged representation. 
     The metering head  5  is connected to the storage container  2  via a locking connection  12 , sealing being effected here via a first gasket  14  and also a second gasket  15  which is disposed between the spindle  8  and the locking connection  12 . The metering head  5  is thereby connected to the locking connection  12  via a spring  13  which is disposed between the inside of the metering head  5  and the locking connection  12 . 
     When the metering head  5  is pressed, the spindle  8  is moved in the direction of the storage container  2  and produces an increased internal pressure in the interior of the pump housing  6 . Because of the increased internal pressure, the inlet valve  7  is closed, whilst the outlet valve  9  is closed by the ball  17  being pressed against the spring  18  because of the internal pressure. As a result, the solution can escape out of the opening  16 . 
     The process of relaxation is illustrated in  FIG. 1 b   . As a result of escape of the solution, the internal pressure in the interior of the pump housing  6  is reduced. Consequently, the spring  18  returns to its initial state and presses the ball  17  downwards so that the outlet valve  9  is closed. Since the spindle  8  is moved upwards and the outlet valve  9  is closed, the result is a pressure decrease in the interior of the pump housing  6 , as a result of which the inlet valve  7  is opened. Subsequently, a pressure equalisation between the interior of the pump housing  6  and the bellows  11  is effected. At the moment at which the metering head  5  returns to its initial position, the internal pressure in the region of the pump housing  6  is almost equalised and the inlet valve  7  is closed. 
     Upon release of the pump head, an upwards movement of the spindle  8  is effected. As a result, suction is produced in the interior of the pump housing  6  and of the through-channel  10 . This suction causes the inflow of fluid through the inlet valve  7  simultaneously into the interior of the pump housing  6  and of the through-channel  10  and, on the other hand, causes secure suction of the upper valve seal, i.e. of the ball  17  towards the lower outlet opening  22  of the spindle channel. This has the result that the inlet valve  7  and the outlet valve  9  are never opened at the same time. 
     In  FIG. 2 , a metering device  1  which is comparable to  FIG. 1  is illustrated, which, instead of bellows, has an inner bag  30  in the storage container  2 . 
     The metering device is also illustrated here in  FIG. 2 a    when the metering head is pressed, whilst  FIG. 1 b    shows the metering device in the retracted position, i.e. when relaxing. 
     When the metering head  5  is pressed, the spindle  8  is moved in the direction of the storage container  2  and produces an increased internal pressure in the interior of the pump housing  6 . Because of the increased internal pressure, the inlet valve  7  is closed, whilst the outlet valve  9  is closed by the ball  17  being pressed against the spring  18  because of the internal pressure. As a result, the solution can escape out of the opening  16 . 
     The process of relaxation is illustrated in  FIG. 2 b   . As a result of the escape of the solution, the internal pressure in the interior of the pump housing  6  is reduced. Consequently, the spring  18  returns to its initial state and presses the ball  17  downwards so that the outlet valve  9  is closed. Since the spindle  8  is moved upwards and the outlet valve  9  is closed, the result is a pressure decrease in the interior of the pump housing  6 , as a result of which the inlet valve  7  is opened. Subsequently, a pressure equalisation between the interior of the pump housing  6  and the inner bag  30  is effected. At the moment at which the metering head  5  returns to its initial position, the internal pressure in the region of the pump housing  6  is almost equalised and the inlet valve  7  is closed. 
     Upon release of the pump head, an upwards movement of the spindle  8  is effected. As a result, suction is produced in the interior of the pump housing  6  and of the through-channel  10 . This suction causes the inflow of fluid through the inlet valve  7  simultaneously into the interior of the pump housing  6  and of the through-channel  10  and, on the other hand, causes secure suction of the upper valve seal, i.e. of the ball  17 , towards the lower outlet opening  22  of the spindle channel. This has the result that the inlet valve  7  and the outlet valve  9  are never opened at the same time. 
     In  FIG. 3 , a metering device according to the invention which has an inner bag  30  analogous to  FIG. 2  is illustrated. The additional difference of this metering device is that, instead of a plastic material valve as inlet valve  7 , a ball valve with a metallic ball is used. 
     When the metering head  5  is pressed, the spindle  8  is moved in the direction of the storage container  2  and produces an increased internal pressure in the interior of the pump housing  6 . Because of the increased internal pressure, the inlet valve  7  is closed by the ball  20  being pressed downwards because of the internal pressure whilst the outlet valve  9  is closed by the ball  17  being pressed against the spring  18  because of the internal pressure. As a result, the solution can escape out of the opening  16 . 
     The process of relaxation is illustrated in  FIG. 3 b   . Because of the escape of the solution, the internal pressure in the interior of the pump housing  6  is reduced. Consequently, the spring  18  returns to its initial position and presses the ball  17  downwards so that the outlet valve  9  is closed. Since the spindle  8  is moved upwards and the outlet valve  9  is closed, the result is a pressure decrease in the interior of the pump housing  6 , as a result of which the inlet valve  7  is opened. Subsequently, a pressure equalisation between the interior of the pump housing  6  and the inner bag  30  is effected. At the moment at which the metering head  5  returns to its initial position, the internal pressure in the region of the pump housing  6  is almost equalised and the inlet valve  7  is closed. 
     Upon release of the pump head, an upwards movement of the spindle  8  is effected. As a result, suction is produced in the interior of the pump housing  6  and of the through-channel  10 . This suction causes the inflow of fluid through the inlet valve  7  simultaneously into the interior of the pump housing  6  and of the through-channel  10  and, on the other hand, causes secure suction of the upper valve seal, i.e. of the ball  17  towards the lower outlet opening  22  of the spindle channel. This has the result that the inlet valve  7  and the outlet valve  9  are never opened at the same time. 
     In  FIG. 4 , a metering device  1  which is comparable to  FIG. 1  is illustrated and has a cone  23  in addition to a spring  18  in the outlet valve  9 . 
     A cone  23  with outlet opening is mounted moveably between the ball  17  and the spring  18  and forms the upper region of the outlet valve  9 . Upon actuation of the pump, the cone  23  is pressed downwards close to the ball  17  and the ball  17  is pressed towards the lower outlet opening  24  of the spindle channel. 
     At the same time, the fluid volume in the chamber of the outlet valve  9  is displaced practically completely by the cone  23 , which is guided downwards, and escapes through the outlet opening  25  in the cone  23  to the exterior, as a result of which the residual volume in the valve chamber is minimised. Escape of the fluid at the side of the cone  23  is not effected since an outlet opening  25  is present in the cone  23 . After emergence of the fluid, the cone  23  remains pressed downwards by the inner spring  18  so that the ball  17  is pressed securely towards the outlet opening  24  of the spindle channel, i.e. the valve forms a tight seal. 
     Upon release of the pump head, an upward movement of the spindle  8  is effected. As a result, suction is produced in the interior of the pump housing  6  and of the through-channel  10 . This suction causes the inflow of fluid through the inlet valve  7  simultaneously into the interior of the pump housing  6  and of the through-channel  10  and, on the other hand, causes secure suction of the upper valve seal, i.e. the ball  17 , towards the lower outlet opening  24  of the spindle channel. This has the result that the inlet valve  7  and the outlet valve  9  are never opened at the same time. 
     Alternatively, a plastic material valve can also be present instead of the ball  17 . In this case, the cone then also has a flat configuration at the bottom in order to exert as close a contact as possible with the valve seal. 
       FIG. 5  shows various embodiments of the outlet valve  9 . 
     Thus  FIG. 5 a    shows a variant in which bellows  19  are provided instead of a ball. These bellows are pressed upwards when internal pressure is present, whilst, with relaxation, i.e. reduction in the inner pressure in the interior, the bellows are moved in the direction of the outlet opening  24  of the spindle channel and seal this tightly. 
       FIG. 5 b    shows a variant in which bellows  19  are provided with a conically tapering tip  29 . The conically tapering tip is moved here upon relaxation in the direction of the outlet opening  24  of the spindle channel so that the outlet opening  24  is closed and sealed by the tip  29 . 
       FIG. 5 c    shows a variant with a spring  18  which is provided with a plastic material cone  31  in the direction of the outlet opening. The plastic material cone  31  is moved here upon relaxation in the direction of the outlet opening  24  of the spindle channel, is placed on the latter and thus closes the outlet opening  24 . 
       FIG. 6  shows a further embodiment of the outlet valve  9 . It is shown here that bellows  19  can also be used instead of a spring  18  in order to effect the restoring force for the ball  17 . 
       FIG. 7  shows further variants of the outlet valve  9 . 
     In  FIG. 7 a   , a variant with a ball  17 , a cone  23  and a spring  18  is illustrated. A lateral outlet channel  32 , via which the solution can exit, is disposed here. 
       FIG. 7 b    shows a variant with a one-part plastic material cone  23  and a spring  18 . A lateral outlet channel  32  is disposed here also. 
       FIG. 7 c    shows a variant with a one-part plastic material cone  23  and a spring  18 . Escape of the fluid at the side of the cone  23  is not effected here since an outlet opening  25  is present in the cone  23 . 
       FIG. 8  now shows a further embodiment of the metering device according to the invention. In  FIG. 8 a   , again the complete metering device with the metering head  5  and the storage container  2  is thereby illustrated. An essential element of this embodiment is that bellows  41  are disposed in the metering head between the inside of the metering head  5  and the locking connection  12 . The embodiment according to  FIG. 8 a    thereby provides one-part elastic bellows  41  which have in addition an integrated sealing function on both sides. For this purpose, the elastic bellows  41  are connected to sealing elements  43  which then enable optimum sealing of the bellows in the direction of the inside of the metering head. The further construction corresponds to that as described in detail in the preceding Figures. The metering head  5  has another modification with respect to the outlet valve  9  as a further alternative here. The outlet valve  9  is now constructed as a modification of the already described embodiment such that a valve piston  40  is provided here instead of the ball. The valve piston  40  is thereby configured such that it has a semicircular bulge on its side directed towards the opening so that the valve opening  45  can be closed. A further advantage of the embodiment according to  FIG. 8 b    resides in the fact that a lateral valve opening  42  through which then the fluid to be transported is conveyed in the direction of the outlet can be provided. 
     As a crucial advantage of this embodiment, it should be mentioned that the bellows  41  are configured as elastic bellows and, as a result of the integrated sealing function thereof, allow optimum operation of the metering device.