Abstract:
The object of the invention is to provide a method and a dispenser in which, compared with known dispensers, the fluid path design is simplified. The dispenser has a medium reservoir ( 19 ) containing a medium to be discharge during one discharge stroke of the dispenser ( 11 ). For this purpose a feed fluid flows through the medium reservoir and discharges the medium through a reservoir discharge opening. For producing a discharge stroke, the dispenser has an actuator ( 25 ), whose actuation at least indirectly leads to an impact spike ( 29 ) penetrating from the outside into the medium reservoir ( 19 ), so as to produce a connection between a pump ( 40 ) for a feed fluid and the medium reservoir. As a result of the pressure of the feed fluid flowing into the medium reservoir, at a point in the medium reservoir ( 19 ) differing from the entry point of the impact spike ( 29 ), an opening is formed.

Description:
BACKGROUND OF THE INVENTION 
   The invention relates to a method and to a dispenser for mixing and discharging a medium mixture mixed from two media. 
   DE 19817417 A (corresponding to U.S. Ser. No. 09/554031) discloses a dispenser, in which a medium to be discharged, e.g. a powder, is received in a blister ring. The user operates an air pump cylinder and presses the blister ring against a hollow impact spike, which perforates a cover foil of a blister chamber. Through said opening, air enters the blister chamber and discharges the medium through the hollow impact spike. Thus, the air enters the medium chamber alongside or through the impact spike and passes out from the same again. This limits the line cross-section and the flow guidance for a good mixing. 
   OBJECT OF THE INVENTION 
   An object of the invention is to provide a method and dispenser simplifying the guidance of the media, which reduces the requirement for easy miscibility of the media and which improves the mixing process. 
   SUMMARY OF THE INVENTION 
   As defined in claim  1 , the invention provides a method in which a first medium, e.g. a feed or delivery fluid, is delivered from a first chamber on operating the dispenser into an initially closed, second chamber on opening the latter, e.g. through an impact spike. Thus, the pressurized first medium enters the second chamber and places the same under media pressure, which brings about the opening of the second chamber. This can take place by the bursting of a wall of the second chamber, e.g. the cover foil of a blister, whose body is pierced from below by the impact spike. Said wall part can be prepared by material weakening, e.g. in the form of a predetermined breaking point. However, it is also possible for the discharge closure element of the second chamber to also be pierced in order to assist the opening under media pressure. The second chamber can also have a displaceable wall part, e.g. a plug, which is perforated, blown off or obviated by a bypass, if media pressure from the second chamber acts thereon. 
   In all cases the media path is simplified, because the flow through the second chamber can take place without any significant deflection, i.e. a straight passage is created. Nevertheless the mixing of the two media is good, because the feed fluid enters in planned manner and as a result of the pressure build-up in the second chamber a certain mixing time is also available and this can contribute to the second medium dissolving in the first medium, e.g. a powder in a liquid. 
   The second medium can be in liquid or solid form, particularly as a powder. It can then be mixed with the first medium, which can be mainly gaseous (air) or liquid and as a result all possible mixture forms or dispersions between the same can form, particularly aerosols with liquid or solid particles, emulsions, solutions or suspensions, as well as foams. In the pharmaceutical sector this is particularly important, e.g. for lyophilizates. Many pharmaceutical substances, which usually form the second medium, are not stable in the liquid or pulverulent administration form, so that they can only be mixed or dissolved just prior to administration. The pharmaceutical substances are often lyophilized powders. However, pharmaceutical substances are often absorbable or surface-active via the nasal mucosa. The feed fluid (first medium) can also contain pharmaceutical substances or can react chemically or physically with the second medium for forming the ultimate pharmaceutical substance. 
   If the discharge closure element is constituted by a foil, the material thickness in the region of the weakening can be minimized to approximately 9 to 12 μm and is therefore smaller than the wall thickness of the remaining foil. Use is more particularly made of metal foils, e.g. aluminium foils. As such weakened points contain no definition of the start of the breaking point, when designing the foil it must be ensured that there is a continuous, propagating tearing open of the foil starting at a specific point in order to e.g. avoid a detonation effect. This could e.g. be brought about by a laser perforation of the material, which can also be guided along the entire predetermined breaking point. Perforation is performed in such a way that also in this area the material remains tight with respect to fluids and gas exchange. 
   Additionally or alternatively to material weakening, in the vicinity of the surface portion to be broken open, the impact spike can pierce or perforate the medium reservoir and this precisely defines the position of the start of tearing open. 
   Advantageously, the second chamber (medium reservoir) can at least be zonally deformable. As a result even in the case of changing external pressures, there is scarcely a pressure difference between atmosphere and the interior of, in particular, the second chamber, which keeps limited the fusion and gas exchange with the atmosphere. As a result, the material thicknesses of the medium reservoir wall can be kept small. 
   In the advantageous use of a blister, the latter usually comprises a moulding, which is e.g. cup or bowl-shaped with an edge and which is closed by a foil material. The latter can be a metal foil, a metal vapour-deposited plastic foil or film or a multilayer foil or film formed from laminates. The choice of the foil material determines the “damming” i.e. the size of the pressure build-up prior to the pressure-caused opening of the discharge closure element. This must be made sufficiently high to ensure that the outflowing media mixture has or can reach the desired use form. In the case of a discharge in the form of a spray through a spraying nozzle, a relatively high initial pressure should be present. 
   According to another embodiment, the medium reservoir has a plug axially displaceably arranged about a movement path. As a result of the axial displacement, the fluid path between the medium reservoir and the discharge opening is freed and this takes place under the pressure rise in the second chamber. 
   The second chamber can be replaceable. Thus, a dispenser can be reloaded for repeated use. It is also possible through manual operation to place the feed fluid in the first chamber initially under a pressure without initiating the overflow into the first chamber. Then, at high speed and corresponding advantages for the mixing process, it passes into the second chamber. In addition, the feed fluid need only be compressed just prior to its discharge and need not be stored for a long time in a pressure-tight reservoir, although this is also possible. 
   These and further features can be gathered from the claims, description and drawings and the individual features, both singly or in the form of subcombinations, can be implemented in an embodiment of the invention and in other fields and can represent advantageous, independently protectable constructions for which protection is claimed here. The subdivision of the application into individual sections and the subheadings in no way limit the general nature of the statements made thereunder. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the invention are shown in the attached drawings, wherein show: 
       FIG. 1  A diagrammatic longitudinal section through a dispenser for performing the method according to the invention. 
       FIGS. 2 &amp; 3  Medium reservoirs (second chambers) in two successive method stages. 
       FIG. 4  A longitudinal section through a further dispenser for performing the method. 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1  shows a dispenser  11  with a base body  12 , which has laterally projecting shoulders  13  on which are placed two fingers of a user. Onto the base body  12  can be engaged or screwed an elongated adaptor  14 , also known as a nose olive and which has at its rounded end a discharge opening  15 . The latter is shown as a relatively large, open hole, but when constructing the dispenser as an atomizer, it can also contain an atomizing nozzle. 
   The base body  12  contains a first chamber  16 , which has a cylindrical section  17  constructed as a pump cylinder and a section  18  connected thereto. At the end thereof is interchangeably inserted a second chamber  19  and is held there by the adaptor. The second chamber comprises a blister with a hemispherical, bowl-shaped plastic moulding  20  and an edge  21 , onto which is sealed a discharge closure element  22  in the form of a metal foil or plastic film tightly sealing the second chamber. The blister is fixed at the edge  21  in tight manner between an upper end face of the base part and the adaptor. 
   The cylinder  17  of the base part  12  is surrounded by a slightly expandable jacket  23 . In the intermediately formed annular clearance  24  is guided an actuator  25  having cylindrical or web-like guide parts  26 . Between the latter, the actuator contains a piston  27 , which runs by means of an inserted or also shaped-on seal  28  in the cylinder  17 . On the piston head is placed or shaped an impact spike  29 , which by a ribbed structure, e.g. a cruciform cross-section, forms overflow channels  30  in the manner to be described hereinafter. 
   At their ends the guide parts or arms  26  of the actuator  25  have detents  31 , which run in guide slots  32  of the jacket  23  and prevent the actuator  25  from detaching itself from the base part  12  following initial snapping in. 
   A restoring spring  33  is located in the cylinder  17  and embraces the impact spike  29 , being supported on shoulders  35  surrounding the connecting opening  34  between cylinder  17  and the following section  18 . It can be a steel helical spring or a plastic spring optionally pointed on the piston  27 . In this case all the parts of the dispenser would be made from plastic, which permits type-pure recycling. 
   The first chamber contains a first medium  36 , which is a feed or delivery fluid, e.g. a liquid or gas such as air. The second chamber (blister  19 ) forms a medium reservoir for a second medium  37 , e.g. pulverulent pharmaceutical substances. 
   The dispenser is used for performing the following method: 
   In preparation for administration, a user places a blister  19  in the dispenser by removing or unscrewing the adaptor  14 , places the blister on the end face  38  of base part  12  and refits the adaptor. The cylinder  17  is then filled with air, which in this case forms the feed fluid  36 . If the user now places two fingers on the shoulders  13  and presses with the thumb on the actuating surface  39  on actuator  25 , he can press the latter upwards and therefore compress the air in the pump  40  formed by cylinder  17  and piston  27 . This takes place until the impact spike  29  strikes against the moulding  20  of the blister  19  and perforates the same (cf. FIG.  3 ). 
     FIG. 3  shows in a perspective sectional representation that the bottom of the moulding of the blister has been perforated by an overflow closure element  41 . As a result of the cruciform structure of the impact spike  29 , in the vicinity of the overflow channels  30  an opening  60  is formed through which the now compressed air enters the blister and places the latter under pressure. 
     FIG. 2  shows that the blister has material weakenings  42  on its sealed-on foil forming the discharge closure element  22  and said weakenings are e.g. in the form of a scoring, embossing or non-continuous laser perforation, which in the example shown is in the form of a rounded off H. Under the media pressure in the blister the foil is therefore torn open along said material weakening and is e.g. folded out into two lateral tongues  43  or into four tongues in the case of an X-shaped material weakening. Thus, the foil is burst by the internal pressure, the feed fluid  36  flows under its pressure through the blister, carries with it the second medium  37  by mixing therewith in order to form a solid aerosol. Through the space  44  formed in the adaptor, the mixture flows to the discharge opening  15  and at the desired point where it has been placed by the user it is e.g. applied to a nostril. 
   In place of the planned material weakening at certain points, these can also be provided in the form of lines or points, this being carried out by the foil manufacturer prior to blister processing. There is also a formation of a mechanical preweakening, which gives rise to a predetermined breaking point. This contributes to allowing the blister to “explode” so as to bring about a sudden whirling up of the substance in the second chamber, but it is necessary to avoid a detonation, which might frighten the user, by a clearly defined tearing open direction, i.e. a more pronounced material weakening at one point and a following reduced “propagating” weakening. 
   It is also possible to constructionally combine the blister with the adaptor  14 , so that said unit can be replaced for further actuation. This ensures that there is also a replacement of the adaptor part possibly coming into contact with body fluid. 
   It is also pointed out that prior to the start of actuation the actuator must overcome a pressure point, which would be formed by the web  45  in slot  32 . The web can be located in fixed manner, so that the detent  31  with its bevel and the widening of the jacket, which can optionally be made elastic by elongated slots, produces the pressure point. The webs  45  can also be break-off webs provided with predetermined breaking points, which produce a precisely predetermined resistance. Thus, even before the start of use, a slight force expenditure is demanded of the user and ensures that actuation is not too timorous and therefore not particularly effective. However, due to the fact that the opening of the overflow closure element  41  (blister bottom) only takes place after producing the pressure in the first chamber, from then on an automatic control is created ensuring a reliable discharge. Even following the perforation of the blister bottom, the piston can optionally be forced further in the discharge direction and can thereby score a foil forming the discharge closure element  22  for the case that the foil has not been torn open solely by air pressure. It then tears open suddenly and in large-area form, so that its opening and therefore the discharge of the second medium takes place through a very large opening. 
   The operation of the pump has tensioned the restoring spring  33  and returns the actuator  25  and therefore the pump piston  27  to the initial position sucking air into the pump. By removing the adaptor  14  and replacing the blister  19  by an unused blister, the dispenser is again ready for use. In the case where it is a disposable dispenser, there is no need for the spring  33 . 
   The relationship of the pump stroke volume to a dead volume in section  18 , including the volume of the second chamber  19 , determines the pressure, which should exceed the predetermined bursting pressure of the discharge closure element  22 . 
     FIG. 4  shows a dispenser, whose base body  12  with shoulders  13  receives an e.g. glass cylinder  19   a , which forms the second chamber and contains the second medium  37 . The cylinder  19   a  is bilaterally closed by, in each case, a piston plug, whereof the lower plug in  FIG. 4  forms the overflow closure element  41  and the upper plug forms the discharge closure element  22 . The piston plugs have an H-shaped longitudinal section with a thinner, central bar  46 , which can form a perforating membrane, particularly in the case of the overflow closure element  41 . They run with sealing lips on the cylinder inner face of the second chamber  19   a . In the vicinity of the discharge closure element  22  it has an overflow channel or bypass  48 , which in the represented inoperative state is closed towards the second chamber by the discharge closure element  22 . 
   The base body  12  guides a sleeve-like actuator  25   a  forming in its interior the first chamber  16  and containing the first medium  36 . The first chamber is bounded by a piston  49 , in whose centre is inserted, by means of a bushing, an impact spike  29  in the form of a hollow needle. 
   The adaptor  14  also present in this embodiment is screwed onto the upper end of the base part  12  and fixes in an upper flange  50  of the first chamber  19  and presses it into a conical receptacle  51  in the base part. 
   The method of operation is similar to that described hereinbefore: 
   When pressure is exerted on the actuating face  39  of actuator  25   a , the latter is moved into the base part  12 . The impact spike  29  perforates the web  46  of the overflow closure element  41  and opens the same. The lower end face  52  of the second chamber  19   a  strikes the piston  49  and presses it downwards, so that the feed fluid  36  flows through the hollow needle  29  into the second chamber  19   a  and mixes with the second medium  37 . If the pressure in said chamber is sufficiently high for the upper piston forming the discharge closure element  22  to be displaced further upwards, the discharge closure is opened, namely by the bypass  48 . Here again the internal pressure in the second chamber  19   a  brings about the opening of the discharge closure. The resulting mixture then flows in a substantially linear manner through the second chamber  19   a  to the discharge opening  15 . In this construction the first chamber  16  is open to the atmosphere. If the feed fluid  36  is air, this does not represent a problem.