Manually operable dosing device for a medium

The invention relates to a manually operable dosing device for a medium with an applicator housing, which has at least one discharge opening for dispensing the medium, with a pumping means, which has a pumping chamber arranged in the applicator housing, and with an elastically flexible membrane, which forms a wall portion of the pumping chamber and is arranged in an elastically movable manner in the applicator housing for changing a chamber volume of the pumping chamber and which is assigned on an outer side facing away from the pumping chamber an actuating surface for a manual pumping movement.

Many different designs of dosing devices for a medium are known. Such dosing devices have manually operable pumping means. Each pumping means is in connection with a medium reservoir. The flow path between the medium reservoir and the pumping chamber can be closed by an inlet valve. To make it possible for the pumping means to perform a discharging operation, the pumping chamber is in operative connection with the discharge opening of the dosing device via an outlet valve. The discharge opening is provided in an applicator housing of the dosing device, the discharge opening serving for the dosing or dispensing of the medium to the surroundings. For actuating the pumping means, a manually operable actuating element is provided. The pumping means may be designed as a thrust piston pump or in some other way.

It is also known to provide bellows pumps, in which the pumping chamber is at least partially formed by an elastic flexible membrane. The compression of the pumping chamber, and accordingly the discharge operation, takes place in a simple way by manually exerting pressure on the flexible membrane, whereby the latter is deformed and inevitably reduces the size of a volume of the pumping chamber. The elastic flexibility of the pumping chamber is designed in such a way that, once the exerted pressure is removed, the membrane automatically reverts to the starting position in which no pressure is exerted, in order to suck the medium that is to be delivered into the dosing chamber.

The object of the invention is to provide a dosing device of the type mentioned at the beginning which makes it possible by simple means for medium to be discharged by manual operation.

This object is achieved by the applicator housing having a flow path from the pumping chamber to the discharge opening, and by the membrane forming an outlet valve of the pumping chamber. By the solution according to the invention, the membrane assumes a multiple function. On the one hand, it forms a wall portion of the pumping chamber. On the other hand, it serves as an application surface for manual operation of the pumping means, and finally it is designed in such a way that it protrudes into the flow path between the pumping chamber and the discharge opening in such a way that it forms the outlet valve of the pumping chamber. Consequently, a number of functional segments of the dosing device are achieved by means of a single component, namely the elastically flexible membrane. The solution according to the invention is suitable for dispensing flowable media or liquids of high or low viscosity, in particular for cosmetic or pharmaceutical purposes.

In an embodiment of the invention, the applicator housing has a ventilating channel, leading to a medium reservoir, and the membrane forms a ventilating valve for the ventilating channel. The ventilating channel makes the dosing device suitable for multiple dosing, since after each dispensing operation the volume of liquid dispensed can be made up by air from the surroundings. The fact that the membrane also forms the ventilating valve for the ventilating channel provides a further function which is integrated in the membrane.

In a further embodiment, the applicator housing is provided with a spray nozzle as the discharge opening. This embodiment is particularly advantageous for dispensing liquids as a spray mist and is suitable in particular for liquids for cosmetic purposes.

In a further embodiment of the invention, the applicator housing is provided with a discharge opening designed for a medium of high viscosity. This allows gels, ointments, creams and the like to be dispensed in particular.

In a further embodiment of the invention, the actuating surface of the membrane is arranged in a clearance of the applicator housing and, in the state of rest in which no pressure is exerted, is aligned in particular such that it is flush with an outer contour of the applicator housing. As a result, the actuating surface can be integrated into the outer contour of the dosing device, and in particular of the applicator housing, in a visually attractive way.

The actuating surface, which is part of the membrane, may either be formed directly as a finger rest, or serves as an application surface for an actuating element which establishes the operative connection between the manual exertion of pressure by an operator and the membrane.

In a further embodiment of the invention, the membrane is produced from an elastomer material as a one-piece, bell-shaped component. The membrane is preferably integrated in an end region of the applicator housing and is aligned at least largely such that it is coaxial with a central longitudinal axis of the applicator housing in the applicator housing.

In a further embodiment of the invention, the applicator housing is of a two-part design, and the membrane is restrained coaxially between an inner part and an outer part of the applicator housing. The membrane is preferably radially prestressed in the mounted position. The clearance is preferably provided on an end region of the outer part of the applicator housing, so that the actuating surface of the membrane can be operated from an end face of the outer part. The outer part and the inner part of the applicator housing are preferably connected to each other positively or non-positively in the axial direction—with respect to the central longitudinal axis of the applicator housing. In the mounted end position of the outer part and the inner part with each other, the membrane is inevitably also fixed along with them in its installation position and is preferably radially prestressed. As a result, a particularly quickly acting valve function is achieved.

In a further embodiment of the invention, the actuating surface of the membrane is provided on the outside of a restraining region of the membrane in the applicator housing and a lip portion forming the outlet valve is provided within the restraining region, and the restraining region of the membrane is designed in particular as a solid joint. When pressure is manually exerted on the membrane, preferably quick opening of the lip portion is brought about, by the chamber that is filled with medium being put under pressure. The increase in pressure leads to opening of the outlet valve. This is a particularly preferred embodiment, since it is ensured that deformation of the membrane inevitably also causes opening of the outlet valve.

In a further embodiment of the invention, a sealing portion of the membrane that is provided in the region of the clearance of the applicator housing is provided as a ventilating valve for the ventilating path, which closes the latter when no pressure is exerted on the membrane and opens it when the membrane is manually compressed. In an analogous way, deformation of the membrane inevitably causes the ventilating path to be opened. The membrane is preferably designed in such a way that, when there is appropriate deformation of the membrane, at the same time both the outlet valve for the pumping chamber and the ventilating valve for ventilating the medium reservoir are opened.

In a further embodiment of the invention, the membrane is produced in one piece from an elastomer material and has a bellows region, on which at least one peripheral or helical groove is formed. The design of the membrane in the form of bellows allows a particularly favorable ratio between a volume that is enclosed in the state of rest of the membrane and a volume that is still enclosed by the membrane at the end of the discharge operation. That is to say that, with the membrane designed in such a way, a greater volume of medium can be delivered, so that the discharge device equipped in this way can be used for a wider range of applications. Moreover, a particularly advantageous deformation behavior of the membrane is achieved by the at least one peripheral or helical groove, since the membrane is deformed at least substantially only in the region that is in the form of bellows. By contrast, an outwardly facing cover plate of the membrane, provided for example as a finger resting surface, is virtually undeformed and consequently makes a favorable force transmission and an advantageous pressure buildup posssible for the dosing means. The bellows region may be formed in particular by an axial arrangement of at least two rings in the form of portions of a cone, respectively oriented conversely and connected to each other in one piece. As a result, at least one peripheral groove is formed and the bellows has a substantially V-shaped or U-shaped cross section, preferably of constant thickness, or a multiple recurrence of such a cross section. The bellows region may also have a geometry that is helical, i.e. similar to a screw thread, it being possible in particular for multi-start constructions, as are known from the area of multi-start screw threads, to be used for the bellows region. As a result, particularly favorable flexibility of the membrane is ensured and flexible materials with different characteristics can be used.

In a further embodiment of the invention, the membrane has, in a preferably annular transitional region between the bellows region and a lip portion forming the outlet valve, at least one groove, running at least partly around the periphery, to isolate the movement between the bellows region and the outlet valve. The groove which runs at least partly around the periphery, which may in particular be provided in those sectors of the transitional region that are coupled with the lip portions acting as outlet valves, achieves the effect that, when the membrane is actuated and deformation of the bellows region occurs as a result, there is no influence on the lip portion, or only little influence. This allows the lip portion to perform its function as an outlet valve without being influenced by the deformation of the bellows region.

In a further embodiment of the invention, at least two lip portions, which have different geometries, are provided on the membrane. The geometries of the lip portions may differ in particular with regard to the wall thickness of the lip portions and/or the length of the lip portions. This offers the possibility of realizing at least two different valve characteristics for the dosing means in a single membrane. Depending on the application, one of the at least two lip portions can be inserted into the dosing device in such a way that the outlet valve is formed by this lip portion. When a somewhat longer lip portion is used, for example, this outlet valve is suitable for dosing media of high viscosity, such as gel for example, and has a soft valve opening characteristic. By contrast, a shorter valve lip has a harder valve characteristic, as is preferably used for dosing media of low viscosity, for example aqueous media.

In a further embodiment of the invention, at least one sealing element is provided on the applicator housing to separate an annular gap portion, provided for guiding the medium, from an annular gap portion that is free of the medium. This ensures reliable separation of the medium from the surroundings, in particular makes it possible to ensure that the medium does not get into the ventilating channel.

Further advantages and features of the invention will become evident from the claims and from the following description of preferred exemplary embodiments of the invention in which reference is made to the drawings.

FIG. 1 shows an embodiment of a dosing device according to the invention for a liquid,

FIG. 2 shows a further embodiment of a dosing device according to the invention, which is designed with a discharge opening for gels, ointments or creams,

FIG. 3 shows a further embodiment of a dosing device according to the invention that is similar to FIG. 1,

FIG. 4 shows the dosing device as shown in FIG. 3 in a perspective and sectional exploded representation,

FIG. 5 shows the dosing device as shown in FIGS. 3 and 4 in a sectional exploded representation,

FIG. 6 shows a detail of the dosing device as shown in FIG. 5 in the region of a spray nozzle in an enlarged representation,

FIG. 7 shows a detail of the dosing device as shown in FIG. 3 in the region of the outlet valve in an enlarged sectional representation,

FIG. 8 shows the sectional representation according to FIG. 7, but with the outlet valve opened,

FIG. 9 shows a further embodiment of a dosing device according to the invention with a membrane in the form of bellows, in a sectional representation,

FIG. 10 shows a further embodiment of a dosing device according to the invention with a membrane in the form of bellows, in a sectional exploded representation,

FIG. 11 shows the inner housing part with sealing ribs in a plan view.

A dosing device 1 as shown in FIG. 1 has a medium reservoir 2, of which only a neck region is represented for reasons of overall clarity. Fitted onto the neck region of the medium reservoir 2 is an applicator housing 3 to 5. In the applicator housing 3 to 5, an elastically flexible membrane 6 is integrated in the way described in more detail below. The membrane 6 is designed like a dome or bell and forms a one-part component of an elastomer material, in particular of silicone, of rubber or of similar material. It is also possible to produce the membrane 6 from a thermoplastic elastomer.

The membrane 6 is restrained between two housing parts of the applicator housing 3 to 5. The membrane 6 is arranged on the end of the applicator housing and is designed at least largely such that it is coaxial with a central longitudinal axis M of the applicator housing 3 to 5. Together with an inner part 5, the membrane 6 forms a pumping chamber 7 of a pumping means of the dosing device 1. The inner housing part 5 of the applicator housing 3 to 5 is supported axially downward on a closure part 3 of the applicator housing 3 to 5. The closure part 3 is screwed by means of a corresponding internal thread onto an external thread of the neck region of the medium reservoir 2. In order to prevent sealing of the neck region 2 and securement against unintentional detachment of the closure part 3 from the neck region, a sealing ring 11, which in particular is elastically compressible, is inserted axially between an end edge of the neck region 2 and an annular shoulder of the closure part 3.

The inner housing part 5 has a connection piece, which protrudes through the sealing ring coaxially with the central longitudinal axis M, protrudes into the neck region of the medium reservoir 2 and is provided with a suction tube not designated any more specifically. To make it possible for the medium reservoir to be ventilated, there is an annular space between the outer casing of the inlet connector of the inner housing part 5 and an inner circumference of the sealing ring 11, even in the pressed state of the sealing ring 11.

The membrane 6 and the inner housing part 5 are fixed in their installation position by the outer housing part 4. The cup-like, outer housing part 4 is pressed axially from above onto the closure part 3, the outer housing part 4 engaging over the sleeve-like closure part 3 over its entire height. The press fit of the outer housing part 4 on the closure part 3 can be seen well from the sectional representation of FIG. 1.

With its dome-like inner contour, the membrane 6 forms the pumping chamber 7 together with the inner housing part 5. The inlet connector of the inner housing part 5 opens out into the pumping chamber 7. The inlet region of the inlet connector can be closed by an inlet valve 8, which is designed as a plunger-type piston valve. A valve stem 10 of the inlet valve 8 is guided axially movably within the inlet region of the inlet connector. Guiding webs 9 serve at the same time as axial securement for a clapper-like end region 10 of the inlet valve 8 facing the medium reservoir. An axial movement in the direction of the pumping chamber 7 consequently allows the inlet valve 8 to be transferred from the closed position, represented in FIG. 1, into its open position.

The outer housing part 4 has in its upper end region a circular clearance, into which the membrane 6 protrudes in such a way that an outer actuating surface 12 of the membrane 6 terminates at least largely flush with the end outer contour of the outer housing part 4. The clearance in the outer housing part 4 is slightly larger than the circular disk-shaped actuating surface 12 of the membrane 6. Following the actuating surface 12, the membrane 6 goes over in the axial direction into an edge region, which widens conically downward with a peripheral sealing portion 14. In the state of rest of the membrane 6 in which no pressure is exerted, this sealing portion 14 terminates in a sealed manner with a peripheral sealing edge 15 at an axially lower end of the clearance of the outer housing part 4. As soon as the membrane 6 is compressed from above by manual pressure of an operator's finger, the sealing portion 14 and the sealing edge 15 come at least partly away from their position of contact and open a ventilating path into the interior of the medium reservoir as long as the membrane 6 is deformed. To make a ventilating path possible from the surroundings into the interior of the medium reservoir, the membrane 6 is provided with at least one passage 16. On the inside of the membrane 6, the inner housing part 5 is also provided with at least one passage 19, so that the ambient air coming from outside when there is deformation of the membrane 7 can pass via the passage 16, the passage 19 and the annular space between the inlet connector and the sealing ring 11 into the medium reservoir.

The outer housing part 4 is provided in the region of a discharge opening with a spray nozzle 18, which is integrated in one piece in the outer housing part 4. In the inner housing part 5 on the one hand and the outer housing part 4 on the other hand, a flow path 17 to the spray nozzle 18 is also formed and is closed by a lip portion 13 of the membrane 6 when no pressure is exerted on the membrane 6. The restraint of the membrane 6 is chosen such that, in the mounted state, the lip portion 13 lies against the inner housing part 5 in a radially prestressed manner. The lip portion 13 of the membrane 6 serves as an outlet valve for the pumping chamber 7. The flow path 17 is formed by corresponding profilings in the inner housing part 5 and in the outer housing part 4, the profilings in each case being integrated in one piece in the respective housing part 4, 5. The lip portion 13 forms a downwardly protruding leg portion of the membrane 6 axially under a restraining region at which the membrane 6 is clamped in a sealed manner annularly between an annular shoulder of the outer housing part 4, delimiting the clearance, and a bottom portion of the inner housing part 5, a remaining bottom surface of the housing part 5 forming the pumping chamber 7 together with the inner contour of the membrane 6. The restraining region forms a solid joint of the membrane 6 for the lip portion 13. As soon as the membrane 6 is subjected to pressure axially from its position of rest, represented in FIG. 1, it is deformed downward by substantially axial movement of the actuating surface 12. In the restraining region, this inevitably brings about a torque, which has the effect when pressure is exerted of a radially downward movement of the lip portion 13, which is relatively thin-walled in comparison with the portion of the membrane 6 surrounding the pumping chamber 7. The flow pressure of the medium caused by actuation of the membrane makes the elastically radially prestressed lip portion open in a way corresponding to its valve function. As a result, together with the pressure increase within the pumping chamber 7 brought about by the compression, the flow path 17 for the medium to be dispensed is opened, whereby the medium, namely the corresponding liquid, can be dispensed through the spray nozzle 18 into the surroundings. As long as pressure is exerted axially on the membrane 6, the ventilating path via the ventilating valve 14, 15 into the medium reservoir is opened, so that a negative pressure in the medium reservoir can be equalized. After relieving the membrane 6 of pressure, it inevitably reverts to the starting position, represented in FIG. 1, on account of its elasticity. As a result of the increase in volume of the pumping chamber 7, a negative pressure is inevitably produced in it, leading to upward opening of the inlet valve 8 and renewed filling of the pumping chamber 7. A renewed discharge operation is brought about by exerting pressure from above on the actuating surface 12 of the membrane 6. The pumping chamber 7 is compressed axially downward. If the membrane 6 is pressed to the bottom of the pumping chamber 7, the inlet valve 8 is also inevitably pressed back into its closed position by this manual compressive movement. At the same time, renewed ventilation of the medium reservoir takes place via the ventilating valve 14, 15, and the medium located in the pumping chamber 7 is once again discharged via the flow path 17 and the spray nozzle 18. This pumping operation can be repeated at will, until a suction tube of the pumping means can no longer suck in any liquid in the medium reservoir.

The embodiment represented by the sectional representation of FIG. 2 corresponds substantially to the embodiment described in detail above with reference to FIG. 1. The dosing device 1a represented in FIG. 2 is therefore merely described with respect to its differences. Components that differ are provided with the same reference numerals but with the addition of the letter a. All other components correspond to the dosing device as shown in FIG. 1, so that either the same reference numerals are used or, to improve overall clarity, the reference numerals have been omitted. With respect to use of the reference numerals, reference is made to this extent to the representation as shown in FIG. 1. The dosing device 1a as shown in FIG. 2 serves preferably for dispensing media of high viscosity, such as gels, creams or ointments. For this purpose, the outer housing part 4a is provided with a modified discharge opening 18a. The flow paths 17a for the medium are also modified with respect to the embodiment as shown in FIG. 1. More details can be seen well from the sectional representation as shown in FIG. 2. The nose-shaped outlet opening 18a is also integrated in one piece in the outer housing part 4a.

In the case of both embodiments, both the closure part 3 and also the inner housing part 5 and the outer housing part 4a are in each case produced from a thermoplastic material. The inlet valve 8 preferably likewise consists of a thermoplastic material.

The embodiment as shown in FIGS. 3 to 8 corresponds substantially to the dosing device 1 as shown in FIG. 1. To avoid repetition, reference is therefore additionally made to the disclosure of the dosing device as shown in FIG. 1. Insofar as details that are also included in the dosing device 1 as shown in FIG. 1 are described in respect of the embodiment as shown in FIGS. 3 to 8, the following disclosure also applies as a description of the embodiment as shown in FIG. 1. The embodiment as shown in FIGS. 3 to 8 is identical to the dosing device 1 as shown in FIG. 1 apart from a minor modification of the nozzle outlet. For the sake of better overall clarity, the same reference numerals have been used for the embodiment as shown in FIGS. 3 to 8 as in the embodiment as shown in FIG. 1. With respect to modified parts, the letter “b” has been added to the respective reference numeral. With regard to the disclosure that is essential for the invention, reference is hereby additionally made expressly to the disclosure content of the drawings according to FIGS. 3 to 8.

As can be seen well from FIGS. 5 to 8, the flow paths 17b in the outer housing part 4b are of a slightly modified design in comparison with the embodiment as shown in FIG. 1. The detailed configuration of the flow paths 17b integrally formed in the outer housing part 4 can be seen well in particular from FIGS. 6 to 8.

The lip portion 13 of the membrane 6 is fitted onto the conical region of the inner housing part 5 under elastic radial prestress and is fixed in this radially prestressed position by the already described pressing between the outer housing part 4b and the inner housing part 5 or closure part 3.

As soon as the pumping chamber 7 is compressed by pressure being exerted on the membrane 6, on the actuating surface 12, the increased pressure of the medium inevitably leads to an elastic opening of the lip portion 13 corresponding to FIG. 8, serving as an outlet valve. When the exertion of pressure on the membrane 6 is removed, the pumping chamber 7 increases in size again. The negative pressure that is produced has the effect of closing the outlet valve in the form of the lip portion 13 and opening the inlet valve 8, in order to allow a corresponding replenishing flow of medium.

In order to avoid correctly aligned mounting of the inner housing part 5 in relation to the closure part 3 and in particular undesired twisting of the inner housing part 5 in relation to the closure part 3 in the mounted operating state of the dosing device 1b, mutually corresponding insertion profilings 20, 21 are provided on the inner housing part 5 and on the closure part 3, respectively, making it possible for the housing part 5 and the closure part 3 to be inserted axially one into the other and, in the fitted-together state, subsequently forming a means of preventing the inner housing part from being twisted in relation to the closure part 3.

The embodiments as shown in FIGS. 9 and 10 correspond substantially to the dosing device 1 as shown in FIG. 1. To avoid repetition, reference is therefore additionally made to the disclosure of the dosing device as shown in FIG. 1. The embodiments as shown in FIGS. 9 and 10 differ from the embodiment according to FIG. 1 substantially with regard to the membrane. For the sake of better overall clarity, the same reference numerals have been used for the embodiments as shown in FIGS. 9 and 10 as in the embodiment as shown in FIG. 1, respectively supplemented by the letters “c” and “d”.

Coinciding with the dosing device 1 as it is known from FIG. 1, the dosing device 1c that is represented in FIG. 9 also has an applicator housing 3c, which can be screwed onto a medium reservoir (not represented) and onto which a closure part 4c is pressed with positive engagement. Fitted onto the applicator housing 3c is an inner housing part 5c, which together with a membrane 6c forms a pumping chamber 7c. The membrane 6c is in this case substantially formed by an end plate 22c, which has a thick wall thickness, and a bellows region 23c, adjoining it in one piece. The bellows region 23c has a thin wall thickness and has a substantially V-shaped cross section. Adjoining the bellows region 23c is a transitional region 24c, which is designed substantially as a planar ring and is formed in one piece with a slightly conically shaped, peripheral lip portion 13c. The bellows region 23c has two helical grooves, which are offset by 180°, are arranged in the manner of a two-start screw thread and, as a result, ensure the particularly advantageous flexibility of the bellows region 23c. The end plate 22c, provided with a greater wall thickness, has a radially outer, peripheral sealing collar 24c. The sealing collar 24c lies flat against an inner end face of the closure part 4c and thereby closes the passage 16c, which is designed substantially identically to the dosing device 1 according to FIG. 1, as long as the membrane is in the rest position, as represented in FIG. 9.

As a departure from the dosing device 1 according to FIG. 1, in the embodiment according to FIG. 9 an inlet valve 8c, designed as a ball check valve, is provided, the valve ball, which is not designated any more specifically, being restricted in an opening stroke by three holding lugs arranged in a circular manner. In the rest position represented in FIG. 9, the valve ball rests in a sealing manner in a substantially conical valve seat. Coinciding with the dosing device known from FIG. 1, a flow path 17c and a discharge opening 18c are provided. The discharge opening 18c is provided for delivery of the medium that is enclosed in the pumping chamber 7c and can be subjected to pressure when the membrane is actuated, and is designed as a discharge opening for media of high viscosity, in particular gel-like media.

The dosing device id represented in FIG. 10 differs from the dosing device 1c according to FIG. 9 merely by the membrane 6c being fitted differently on the inner housing part 5c. Furthermore, a different closure part 4c is provided, equipped with a spray nozzle 18c for the discharge of media of low viscosity, in particular aqueous media. In the representation of FIG. 10 it is evident that the membrane 6c has two differently shaped lip portions, of which a first lip portion 13.1 is made shorter than a second lip portion 13.2. As a result, different valve characteristics are obtained in conjunction with the inner housing part 5d. In this case, the shorter lip portion 13.1 is intended for a higher pressure buildup in the pumping chamber 7c, and is therefore suitable in particular for aqueous media of low viscosity, which are to be discharged in a finely atomized form. By contrast, the longer lip portion 13.2 is designed for the outlet valve to open already under low pressure, and is therefore suitable in particular for media of high viscosity, in particular gels.

In the embodiment represented in FIG. 10, the closure part 4d is equipped with a spray nozzle 18d for media of low viscosity. Correspondingly, the membrane 6c is mounted on the inner housing part 5c in such a way that the spray valve is formed by the inner housing part 5c and the short lip portion 13.1. In an embodiment of the dosing device which is not represented but is suitable in particular for media of high viscosity, such as gels, the inner housing part is in operative connection with the longer lip portion and forms the spray valve. In the case of the membranes 6c and 6d, as they are represented in FIGS. 9 and 10, provided on an end face of the transitional region 26c that is facing the inner housing part 5c or 5d is a relief groove 25c or 25d, respectively, running at least partly around the periphery and intended for creating a mechanical isolation between the bellows region 23c or 23d and the lip portions 13c or 13.1 and 13.2, respectively.

To actuate the dosing devices 1c or 1d, only the embodiment of which according to FIG. 9 is referred to below by way of example, the user must exert an operating force on the actuating surface 12c. The actuating force has the effect of putting the medium that is enclosed in the pumping chamber 7c under pressure. When an adequate pressure level is reached, the lip portion 13c is deflected from the rest position, represented in FIG. 9, into an opening position, so that the medium can flow along the flow path 17c and past the lip portion 13c into the discharge opening 18c and from there away into the surroundings. The flowing away of the medium has the effect of reducing the volume that is enclosed in the pumping chamber 7c and of causing an elastic deformation of the membrane 6c. With continued application of the actuating force and the associated discharge of medium, the membrane 6c comes to lie with the end plate 22c on the inner housing part 5c. In this situation, the sealing collar 24c has also come away from the inner end face of the closure part 4c and consequently opens the passage 16c to the medium reservoir (not represented). When the end plate 22c impinges on the inner housing part 5c, the discharge operation ends and the user reduces the actuating force on the membrane 6c. This allows a return stroke of the membrane 6c and re-filling of the pumping chamber 7c with medium from the medium reservoir to begin.

Since the membrane 6c is designed in the manner of a multi-start helical spring, it has the tendency to be deformed back again into the starting position according to FIG. 9. The recovery causes a negative pressure to be produced in the pumping chamber 7c. The negative pressure brings about opening of the inlet valve 8c and consequently a replenishing flow of medium from the medium reservoir (not represented), since the lip portion 13c seals off the flow path 17c and consequently prevents ambient air from flowing into the pumping chamber 7c. In the meantime, ambient air can flow through the opened passage 16c into the medium container to make up the difference and equalize the pressure there. As soon as the sealing collar 24c resumes contact with the inner surface of the closure part 4c, and consequently prevents further movement of the end plate 21c, the passage 16c is closed and the return stroke is completed by re-filling of the pumping chamber 7c.

According to FIG. 11, the applicator housing 5c is provided with two sealing ribs 27c, which extend in the axial direction on the conical outer surface of the applicator housing 5c and are made to continue from there onto the planar, annular region of the applicator housing 5c. The sealing ribs 27c perform the task of separating the annular gap that is formed between the applicator housing 5c and the membrane and can be exposed to medium via the flow path from an annular gap portion facing away from it. In addition, the sealing ribs 27c also seal the membrane off at the end. This prevents medium from penetrating into the annular gap portion arranged alongside the ventilating channel before, during and after the discharge operation. The sealing ribs locally widen the lip portions, formed as a conically peripheral skirt, in such a way that there is a press fit between the applicator housing 5c and the membrane, whereby the desired sealing effect is achieved. This makes it possible to prevent medium from collecting in the ventilating channel and possibly leading to contamination of the ambient air flowing into the medium reservoir. Provided on the applicator housing 5c is a coding surface 28c, which is intended to enable the applicator housing 5c to be installed in the closure part 4c in the correct position, so that incorrect mounting is virtually ruled out. Use of the applicator housing 5c described in FIG. 11 is not restricted to the embodiment of FIG. 9, but can be applied to all the dosing devices described above.

Manually operable dosing device for a medium

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CPC

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