SEAL FOR AN INHALATION DEVICE

Abstract

The invention relates to the field of inhalation devices for liquids. In particular, the invention relates to an improved seal construction for an inhalation device having a nebulizing nozzle and a piston which moves relative to a pumping chamber in order to generate pumping pressure and to an inhalation device comprising such seal.

An inhalation device for medically active liquids (F) for generation of an aerosol comprises a housing (1), an impingement-type nozzle (6) for generating the nebulised aerosol by collision of at least two liquid jets, the nozzle (6) being firmly affixed to the user-facing side of the housing (1) such as to be immobile relative to the housing (1), inside the housing (1) the inhalation device comprises a reservoir (2) for storing a liquid (F), a pumping device with a pumping chamber (3) for generation of a pressure inside said pumping chamber (3), wherein the pumping chamber (3) is fluidically connected with the reservoir (2), a riser pipe (5) which can be received with at least one reservoir-facing, interior end (5A) in said pumping chamber (3), and said nozzle (6) which is connected liquid-tight to an exterior end (5B) of the riser pipe (5), wherein the interior volume of the pumping chamber (3) is changeable by means of relative motion of the pumping chamber to the riser pipe (5) or vice versa.

A gap (10) can be present between an outside of said riser pipe (5) and an inside of said pumping chamber (3), and a seal (9) bridging said gap (10) in order to minimize pressure loss when a pressure is generated inside said pumping chamber (3).

Said seal (9) can be fixed to said outside of said riser pipe (5), and be moveable with respect to said inside of said pumping chamber (3).

Claims

1. An inhalation device for medically active liquids for generation of an aerosol, comprising a housing, an impingement-type nozzle for generating the nebulised aerosol by collision of at least two liquid jets, the nozzle being firmly affixed to a user-facing side of the housing such as to be immobile relative to the housing, inside the housing the inhalation device comprises a reservoir for storing a liquid, a pumping device with a pumping chamber for generation of a pressure inside said pumping chambe, wherein the pumping chamber is fluidically connected with the reservoir, a riser pipe which can be received with at least one reservoir-facing, interior end in said pumping chamber, and said nozzle which is connected liquid-tight to an exterior end of the riser pipe, wherein the interior volume of the pumping chamber is changeable by means of relative motion of the pumping chamber to the riser pipe or vice versa, wherein a gap is present between an outside of said riser pipe and an inside of said pumping chamber, a seal bridging said gap in order to minimize pressure loss when a pressure is generated inside said pumping chamber, characterized in that said seal is fixed to said outside of said riser pipe.

2. An inhalation device for medically active liquids for generation of an aerosol, comprising a housing, an impingement-type nozzle for generating the nebulised aerosol by collision of at least two liquid jets, the nozzle being firmly affixed to a user-facing side of the housing such as to be immobile relative to the housing, inside the housing the inhalation device comprises a reservoir for storing a liquid, a pumping device with a pumping chamber for generation of a pressure inside said pumping chamber which is moveable relative to the housing or to the nozzle, wherein the pumping chamber is fluidically connected with the reservoir, a riser pipe which can be received with at least one reservoir-facing, interior end in said pumping chamber, and said nozzle which is connected liquid-tight to an exterior end of the riser pipe that is immobile and firmly attached to the housing or to the nozzle, wherein the interior volume of the pumping chamber is changeable by means of relative motion of the pumping chamber to the riser pipe, characterized in that a gap is present between an outside of said riser pipe and an inside of said pumping chamber, the gap being bridged by a seal for minimizing pressure loss when a pressure is generated inside said pumping chamber.

3. The inhalation device according to claim 2, wherein said seal is fixed to said outside of said riser pipe.

4. The inhalation device according to claim 3, wherein said outside of said riser pipe exhibits a higher surface roughness than said inside of said pumping chamber.

5. The inhalation device according to claim 3, wherein said riser pipe exhibits a constricted region or an expanded region.

6. The inhalation device according to claim 2, wherein said seal is being fixed to said inside of said pumping chamber and moveable with respect to said outside of said riser pipe.

7. The inhalation device according to claim 6, wherein said outside of said riser pipe exhibits a lower surface roughness than said inside of said pumping chamber.

8. The inhalation device according to claim 6, wherein said inside of said pumping chamber exhibits a recess or a rim.

9. The inhalation device according to claim 2, wherein said seal is an O-ring, a flat ring, a piston ring, or a tube.

10. The inhalation device according to claim 2, wherein said seal is made of an elastomer, Polytetrafluoroethylene, or a metal.

11. The inhalation device according to claim 2, wherein the same comprises at least two of said seals, being arranged serially.

12. The inhalation device according to claim 11, wherein at least two of said seals are spaced apart such as to prevent a tilting of the riser pipe in the pumping chamber.

13. The inhalation device according to claim 4, wherein said riser pipe exhibits a constricted region or an expanded region.

14. The inhalation device according to claim 7, wherein said inside of said pumping chamber exhibits a recess or a rim.

15. The inhalation device according to claim 1, wherein said seal is an O-ring, a flat ring, a piston ring, or a tube.

16. The inhalation device according to claim 1, wherein said seal is made of an elastomer, Polytetrafluoroethylene, or a metal.

17. The inhalation device according to claim 1, wherein the same comprises at least two of said seals, being arranged serially.

18. The inhalation device according to claim 17, wherein at least two of said seals are spaced apart such as to prevent a tilting of the riser pipe in the pumping chamber.

Description

DESCRIPTION OF FIGURES

[0043] FIG. 1 shows schematically a known nebulizer for medically active liquids prior to its first use.

[0044] FIG. 2 shows the embodiment of FIG. 1 before initially filling the pumping chamber.

[0045] FIG. 3 shows the situation during the first activation.

[0046] FIG. 4 shows the situation at the end of the first activation.

[0047] FIG. 5 shows an embodiment of the inhalation device with a seal being fixed to the pumping chamber.

[0048] FIG. 6 shows a detail of another embodiment of an inhalation device with a seal being fixed to the pumping chamber.

[0049] FIG. 7 shows an embodiment of the inhalation device with a seal being fixed to the riser pipe.

[0050] FIG. 8 shows a detail of FIG. 6.

[0051] FIG. 9 shows a detail of FIG. 7.

[0052] FIG. 10 shows a detail of FIG. 8.

[0053] FIG. 11 shows a detail of FIG. 9.

[0054] FIGS. 12-14 show schematic sectional views of different embodiments regarding the arrangement of a seal.

[0055] FIGS. 15-17 show schematic sectional views of different embodiments regarding the shape of a seal.

[0056] In FIGS. 1 to 4, an exemplary inhalation device for medically active liquids as known from co-pending patent application EP17168869.0 is depicted schematically and not-to-scale. FIG. 1 shows the situation prior to first use.

[0057] The inhalation device comprises a housing 1, which is preferably shaped and dimensioned such that it can be held with one hand and can be operated by one finger, e.g. the thumb (not shown). A reservoir 2 for storage of a medically active liquid F is located inside the housing 1. The depicted reservoir 2 is designed to be collapsible; that means that during proceeding emptying, the elastic or at least limp walls buckle, so that the underpressure which is necessary for extraction of a certain amount of liquid is not, or almost not, increased. A similar effect can be achieved when a rigid container has a moveable bottom by means of which the interior volume of the reservoir can also be successively be reduced (not shown).

[0058] Further, the inhalation device comprises a pumping device with a pumping chamber 3 within the housing 1 for generation of the desired pressure which is necessary for emitting liquid F and nebulizing the same. The pumping device can also comprise additional, not depicted components (push button, locking device, etc.).

[0059] Pumping chamber 3 is fluidically connected with reservoir 2 by means of an inlet check valve 4. Check valve 4 serves for allowing inflow of liquid F into the pumping chamber 3, and blocks a back flow of liquid F into reservoir 2 upon release of the not-depicted locking mechanism.

[0060] As a means for the storage of potential energy 7, a spring is provided which is coupled with one (upwards directed) end to the pumping chamber 3 and which is supported at housing 1 (lower part of the figure).

[0061] The inhalation device further comprises a riser pipe 5 with at least one reservoir-facing, interior end 5A which can be received in said pumping chamber 3. In other words, riser pipe 5 can at least partially be pushed into pumping chamber 3, resulting in a decrease of the interior volume of pumping chamber 3. The term “interior volume” describes that volume which extends from the reservoir-facing inlet of the pumping chamber 3 to the place where the interior end 5A of the riser pipe 5 is located. In the depicted situation, riser pipe 5 is almost entirely contained in the pumping chamber 3. As a result, the interior volume, situated between check valve 4 and the interior end 5A of riser pipe 5, is at a minimum.

[0062] Preferably, in the section which serves for the reception of the riser pipe, pumping chamber 3 has section with an circular inner cross section that corresponds to the (then also) circular outside cross section of the according riser pipe section. Of course, other cross section shapes are possible as well.

[0063] In order to minimize leakage and prevent liquid F from leaving pumping chamber 3 in an undesired way, according to one solution known in the art, the surface roughness of both the outside of riser pipe 5 as well as the respective inside surface section of pumping chamber 3 is very low, so that both surfaces virtually touch each other.

[0064] According to the depicted embodiment, check valve 4 is arranged between reservoir 2 and inlet of pumping chamber 3.

[0065] Finally, the inhalation device comprises a nozzle 6 which is connected liquid-tight to an exterior end 5B of riser pipe 5. Nozzle 6 can be any known nozzle which is suitable for nebulizing/atomizing liquid. The nozzle 6 which is depicted as an example uses the principle of nebulization by means of two colliding liquid jets. Preferably, the cross sections of the liquid-containing channels are relatively small, and typically, in the region of microns.

[0066] Also depicted is an optional outlet valve 8 inside riser pipe 5 for avoiding back flow of liquid or air into the exterior end 5B of the same from the outside. Outlet valve 8 is arranged in the interior end 5A of riser pipe 5. Liquid F can pass outlet valve 8 in direction of nozzle 6, but outlet valve 8 blocks any undesired back flow in the opposite direction.

[0067] As can be seen in FIG. 1, in the depicted example, riser pipe 5 is designed immobile and firmly attached to housing 1, indicated by the connection in the region of exterior end 5B with housing 1. Riser pipe 5 is also firmly attached to nozzle 6, which in turn is attached to housing 1 as well. On contrary, pumping chamber 3 is designed to be moveable with respect to housing 1 and nozzle 6. The benefits of this design have already been explained; reference is made to the respective sections above. It is noted that the invention can be used as well in the case of an immobile pumping chamber and a moveable piston.

[0068] FIG. 2 shows the embodiment of FIG. 1 when initially filling pumping chamber 3. Pumping chamber 3 is pulled down, loading the means for the storage of potential energy 7. Outlet valve 8 is closed due to underpressure inside pumping chamber 3, and check valve 4 is open to reservoir 2. In the following, this situation is also referred to as the “low pressure phase”. Increasingly collapsing walls of reservoir 2 allow its inside pressure remain nearly constant, while pressure inside pumping chamber 3 drops because of the downwards motion pulling pumping chamber 3 off riser pipe 5, increasing the interior volume of pumping chamber 3.

[0069] As a result, interior volume of pumping chamber 3 fills with liquid F from the reservoir.

[0070] In FIG. 3, the situation during the first activation of the inhalation device is shown. Means for the storage of potential energy 7 has been released from the loaded position as shown in FIG. 2. It pushes the pumping device comprising pumping chamber 3 onto riser pipe 5, the interior end 5A of which coming closer to check valve 4 now being closed. As a result, the pressure inside pumping chamber 3 rises and keeps valve 4 being closed, but opens outlet valve 8. Liquid F rises inside riser pipe 5 towards its exterior end 5B and nozzle 6. This situation is also referred to as the “high pressure phase” or “emission phase”.

[0071] FIG. 4 shows the situation at the end of the first (or any subsequent) activation. Means for the storage of potential energy 7 is in its most relaxed end position (spring fully extended). Also, pumping chamber 3 has been pushed almost entirely onto riser pipe 5 such that the interior volume of pumping chamber 3 reaches its minimum. Most of liquid F previously contained inside pumping chamber 3 has passed outlet valve 8 into riser pipe 5. Liquid F already contained within riser pipe 5 has been pushed towards, and though, nozzle 6, where the desired nebulization takes place, producing a spray. This situation is also referred to as the “emission phase” which is also part of aforesaid “high pressure phase”.

[0072] In FIG. 5, a schematic detail of another inhalation device known in the art is depicted. This detail shows a riser pipe 5 which is partially inserted in a corresponding bore hole of a pumping chamber 3. A seal 9 is located at the top end of the pumping chamber inside a recess forming a shoulder, the recess being closed by a lid 14, thus forming a groove dimensioned to accommodate the seal. Thus, when moving riser pipe 5 with respect to pumping chamber 3, friction between seal 9 and riser pipe 5 occurs which can result in abrasion of particles (not shown). Further, the depicted construction makes use of a certain number of individual pieces and geometrical features, making it difficult to fabricate.

[0073] Looking at FIGS. 6 and 7, a situation comparable to the one shown in FIG. 4 is depicted, but with the spray being omitted, as well as already introduced reference numerals. However, in addition to the previous figures, a seal 9 is present which is placed at slightly different locations in FIG. 6 and FIG. 7, respectively. Note that, with regard to said location, the situation of the device shown in FIG. 5 is comparable to the situation of the device shown in FIG. 6, i.e. seal 9 is attached to pumping chamber 3 in both cases.

[0074] As can be seen more precisely in FIGS. 8 and 9 which show details of FIGS. 6 and 7, respectively, seal 9 is arranged in a gap 10 which is present between the outside of the riser pipe 5 and the inside of the pumping chamber 3.

[0075] While in the example of FIG. 10, showing a further detailed view of FIG. 8, seal 9 is fixed to the inside of pumping chamber 3, in the device as shown in FIG. 11, showing a further detailed view of FIG. 9, said seal 9 is fixed to the outside of riser pipe 5, and thus moveable with respect to inside of pumping chamber 3.

[0076] In the present examples, seal 9 is respectively arranged in a circumferential groove 13, which in FIG. 11 is arranged in the outside of riser pipe 5, whereas in FIG. 10, groove 13 is arranged in the inside wall of pumping chamber 3.

[0077] An additional advantage achieved with the embodiment of FIG. 9 and FIG. 11 wherein the seal 9 is fixed to the riser pipe 3 is that, during the depicted high pressure and emission phase, particles which may in some cases be formed from the seal 9 by abrasion or friction are not released into the liquid F, as in the case of the embodiments of FIG. 8 and FIG. 10, but into the opposite direction, as indicated by the arrows 11 and 12, respectively.

[0078] Hence, during said phase, liquid F is not contaminated by abrasive particles, which is a significant improvement with respect to the solutions known up to date in the field of inhalation devices.

[0079] Although a certain possibility exists that, during the subsequent low pressure phase which serves for refilling the pumping chamber 3, particles might be drawn back into the pumping chamber through region of the seal 9, the extent of contamination by particles during this phase is significantly lower. Firstly, the significantly lower pressure itself leads to a smaller amount of particle laden liquid F which can pass seal 9 during movement. Secondly, since the pressure which is rather close to ambient pressure (in the low pressure phase, the maximum possible difference is 1 bar, compared to 200 bar and more during the high pressure phase), the mechanical load which leads to friction and thus abrasion is significantly lower as well. Hence, less particles are generated during the low pressure phase, and thus, less particles will be transported into the pumping chamber 3.

[0080] Furthermore, the outside wall quality of riser pipe does not have to be particularly high if the seal is fixed to the riser pipe as shown in FIG. 9 and FIG. 11. Neither moves the outside wall along the seal, thus not resulting in any abrasion caused by such movement, nor must any complex measures be taken in order to make gap 10 as small as possible, because also larger gaps can securely be bridged by an accordingly selected and positioned seal 9.

[0081] In fact, only that section of inside wall of pumping chamber 3 which comes into contact with seal 9 should be of a high quality (low surface roughness, high wear resistance). However, if pumping chamber 3 is fabricated e.g. by injection moulding or the like, only one high quality master must be provided which can then be used for fabrication of a large number of pumping chambers, all providing accordingly high quality inside wall sections. Thus, the solution according to the invention provides also a cost effective solution.

[0082] In FIG. 12, a schematic sectional view of the region with seal 9 is depicted. In this embodiment, seal 9 is located in a groove 13 which is arranged at the outside of riser pipe 5 (only a section thereof is shown). As can be seen, the surface quality of said outside can be rather low, since it does not come in physical contact with the inside wall of pumping chamber 3. Gap 10 is bridged by seal 9. Only the surface quality of the inside wall of pumping chamber should be high. The various surface qualities are indicated by a bumpy and a flat line in the drawing, respectively.

[0083] In FIG. 13, the situation is depicted with seal 9 being fixed to the pumping chamber 3. Again, a groove 13 holds seal 9 in place. Vice-versa to the previous embodiment, now, surface quality of riser pipe 5 should be high, whereas surface quality of pumping chamber 3 can be low.

[0084] In FIG. 14, which shows a basic situation comparable to the one in FIG. 12, seal 9 rests against two shoulders which extend radially from the otherwise flat outside of riser pipe 5. The space between said shoulders is dimensioned so that seal 9 cannot slide along longitudinal axis of riser pipe 5 (dash-dotted vertical line), and again, surface quality of outside of riser pipe 5 can be low.

[0085] FIG. 15 shows a preferred seal arrangement in side view. In this case the seal is an o-ring with round cross section. The o-ring is in contact with the pumping chamber and can be arranged in a grove of the riser pipe.

[0086] FIG. 16 shows an alternative seal arrangement comprosing a pluratity of sealing planes, either arranged due to a plurality of rings, or through the shape of the seal, e.g. by including one or more notches in the seal.

[0087] FIG. 17 shows a further alternative seal arrangement, showing a protruding tip from a broader base of the seal. This arrangement allows for high surface pressure to the inner wall of the pumping chamber.

LIST OF REFERENCES

[0088] 1 housing

[0089] 2 reservoir

[0090] 3 pumping chamber

[0091] 4 check valve

[0092] 5 riser pipe

[0093] 5A interior end

[0094] 5B exterior end

[0095] 6 nozzle

[0096] 7 means for the storage of potential energy

[0097] 8 outlet valve

[0098] 9 seal

[0099] 10 gap

[0100] 11 arrow

[0101] 12 arrow

[0102] 13 groove

[0103] 14 lid

[0104] F liquid