EP1817114B1 - Metering device for at least one medium - Google Patents

Description

The invention relates to a metering device for at least one medium, with a medium reservoir and with a pump connected to the medium storage device, wherein the medium reservoir or the pumping device held by spring force in the closed position ventilation valve and wherein the venting valve is associated with a control member such that the control member Ventilation valve opens during a pumping movement of the pumping device.

Under a spring-loaded ventilation valve is both a movable elastic deformation properties and resettable vent valve to understand that at least partially consists of an elastomeric material, as well as a depleted by an external spring arrangement spring force. Such a metering device is used for the metering of liquid, gelatinous, powdered media or combinations thereof. The media can be provided in particular for pharmaceutical or cosmetic applications. The metering device allows the discharge of a predetermined amount of medium, with an exact dosage of the medium may be necessary for pharmaceutical applications.

In the DE 44 38 364 A1 a metering device is described in which a medium storage is closed by a designed as a thrust piston pump device. The pumping device has a filling channel, which is also suitable as a ventilation channel for the medium storage. In order to allow an inflow of ambient air into the medium storage, for example, to compensate for pressure caused by the pumping device medium discharge, designed as an annular seal vent valve is provided. This seal surrounds the pumping device at least partially elastically and thus closes the ventilation channel between the medium reservoir and the environment. When a pressure difference occurs between the medium reservoir and the environment, for example at a negative pressure in the medium reservoir allows the seal an influx of ambient air into the medium storage by an elastic deformation. As soon as the pressure difference falls below a pressure level determined by the elastic properties of the seal, the seal closes the ventilation channel and thus prevents further inflow of ambient air. This process always takes place when there is a pressure difference which can cause an elastic deformation of the seal. This can also be the case independently of an actuation of the metering device.

In particular, for pharmaceutical media in addition to the dosage of an exact amount of medium is also important, which amount of active ingredient is dosed with the appropriate amount of medium. In known metering devices, a creeping change in the concentration of the active ingredient, in particular due to the escape of volatile, evaporated medium components from the medium reservoir through the ventilation channel, can occur. Thus, on the basis of a constant dosage of the medium amount, a change in the metered amount of active ingredient can occur. However, such a change in the dose of active ingredient is undesirable in pharmaceutical media.

From the US 4,153,203 is a discharge device with liquid storage is known in which an actuating handle directed towards an extension direction is arranged, which serves the purpose to open at the end of an actuation operation, a venting valve of the liquid reservoir. A very similar design is also the EP 0689877 A2 refer to.

From the US 4,694,976 In the course of a pumping operation, this piston sleeve is displaced in such a way that on its side remote from a pumping chamber a path opens along which air can pass into a fluid reservoir on which the piston pump is provided ,

The problem underlying the invention is to improve the operation of the generically provided ventilation valve.

This object is achieved by a metering device of the type mentioned, in which the venting valve is designed as a hose cuff which encloses a rotationally symmetrical pump section coaxial with the pump axis, wherein the hose cuff and the control member are provided with mutually corresponding control surfaces, for an opening operation of the venting valve and wherein the control surfaces are oriented inclined relative to the pumping axis such that during a pumping movement a radial motion component is exerted outwardly of the tubing cuff away from the pumping axis.

The vent valve is regularly opened only when an actuation of the pumping device takes place. This can prevent that an uncontrolled Gaus exchange between the trapped in the medium storage volume and the environment takes place. An uncontrolled gas exchange, which takes place in a known from the prior art metering device by thermal expansion or shrinkage of the trapped in the medium storage volume and the associated pressure difference, possibly leading to the undesirable outflow of volatile, evaporated medium components. By controlling the ventilation valve by means of the control member, in particular by a mechanical action of the control member on the vent valve is achieved that the vent valve may have a deviating from the prior art characteristic. In known ventilation valves, a response to a relatively small pressure difference must be ensured. This pressure difference is primarily caused by the discharge of a small amount of medium from the medium reservoir and requires a sensitive response of the ventilation valve, so that the ventilation of the medium reservoir and the dosing of a new dosing is guaranteed. In the controlled by the controller Ventilation valve, however, a valve characteristic can be chosen so that the vent valve without the action of the control element or only responds to very large pressure differences, since the control of the vent valve is ensured in a dosing by the control member. This can be prevented that even at low pressure differences, an outflow of volatile medium components from the medium storage takes place, so that a concentration of active ingredients in the medium remains constant over a long period.

The venting valve and the control member are provided according to the invention with mutually corresponding control surfaces which can be brought into contact with each other for an opening operation of the venting valve. An opening operation of the ventilation valve is effected by a forced control in which a control surface of the control member interacts with a control surface of the ventilation valve and thus positively and / or non-positively causes a deflection of the ventilation valve from a closed position to an open position. The necessary for an actuation of the venting valve actuating force is initiated by the control member via the control surfaces on the Belüf relief valve, so that a characteristic of the venting valve can be adapted to the initiated by an operator on the control member actuating forces. Since the actuation forces can be many times higher than the pressure forces which occur due to the pressure difference after metering a quantity of medium in the medium reservoir, the opening behavior of the venting valve can be designed for a significantly higher pressure level compared to known venting valves. Thus, an undesirable escape of volatile medium components from the medium reservoir at low pressure differences, as may occur in known ventilation valves, can be effectively prevented.

The ventilation valve according to the invention is designed as a hose sleeve which encloses a rotationally symmetrical pump section coaxially with the pump axis. This allows a particularly simple Structure and advantageous reliability of the ventilation valve. A rotationally symmetrical pump section can be produced with high precision by means of a cost-effective production method, such as plastic injection molding. In this case, the pump section in particular represents an outer contour of a functional part of the pumping device. A hose sleeve which can be made to ensure the valve function of an elastic material, in particular an elastomer such as silicone, rubber, polyethylene or thermoplastic elastomer is, with regard to one in the hose cuff occurring power flow particularly advantageous. This applies both to the force flow that is required to produce the elastic bias at rest, as well as for the power flow that occurs in deflection of the hose cuff when opening the vent valve. In both cases occur in the preferably designed as a rotationally symmetrical component hose cuff substantially only forces in the circumferential direction, which can be derived by the tubular contour particularly advantageous and thus ensure a precise function and a long life of the hose cuff. A valve seat, which represents the sealing surface between the hose cuff and the pump section, can be designed as a pump section area in such a construction of the ventilation valve. Due to the flexibility of the hose cuff a tolerance compensation is ensured within wide limits, so that the function of the ventilation valve is ensured even with variations in manufacturing accuracy of hose sleeve and pump section.

According to the invention, said control surfaces are aligned in such an inclined manner with respect to the pump axis that during a pumping movement a radial movement component is exerted on the hose cuff away from the pump axis. As a result, opening of the ventilation valve can be brought about in a particularly simple manner. Due to the inclination of the control surfaces relative to the pump axis, a wedge effect occurs, which leads to a displacement of the hose cuff to the outside. Thus, the hose cuff is lifted from the cylindrical pump section and gives at least one passageway free, can flow through the ambient air into the medium tank. The wedging effect is particularly advantageous when the control surfaces occupy an acute angle with respect to the pump axis.

In an embodiment of the invention, the control member is arranged on a liftable relative to the vent valve actuating part of the pumping device, wherein the vent valve in the unloaded state of the pumping device in a - related to a pump axis - axial distance to the control member is arranged, which is less than an actuating stroke of actuating member. This allows a simple construction of the pumping device and the control member provided thereon. The control member is arranged on the liftable operating part of the pumping means, which is provided for actuation of the pumping means. An introduction of force by a user into the pumping device takes place via the actuating part, so that the force introduced by the user can also be transmitted directly to the control member. An executed by the introduction of force actuating stroke of the pumping device causes in addition to the dosage of the medium and an approximation and the mechanical contact of the control surfaces of the control member and vent valve, so that with the implementation of the actuating stroke and a control of the vent valve is achieved. To ensure this, the distance between the control member and the vent valve in an unloaded rest position of the operating part in an axial direction of the pump device is selected to be lower than the actuating stroke. As soon as a complete operating stroke of the operating part is performed, it is inevitably ensured that the control member interacts with the venting valve and causes the venting valve to open.

In a further embodiment of the invention, the vent valve is arranged axially resilient between a valve opening and a valve closing position, and the control member transfers the vent valve axially in the valve opening position. The axial compliance of the ventilation valve can be done by a complete axial displacement of the vent valve or only by an elastic deformation of at least a portion of the vent valve. An axial movement of the control member, in particular by a pumping movement, leads to the desired valve opening operation.

In a further embodiment of the invention, the ventilation valve is designed to be axially elastically deformable, and the ventilation valve is attributable to the Ventilöffnungsstettung in the valve closing position by its elastic return properties. The control member exerts an axial deformation or compression during its axial movement on the venting valve or on a section of the venting valve until the venting valve is displaced axially so far that a corresponding venting path is released. With a corresponding return stroke and a removal of the control member resulting therefrom, the vent valve returns to its initial position and thus back to its valve closing position. This provision is made by the elastic material properties of the ventilation valve or a corresponding section of the ventilation valve.

In a further embodiment of the invention, the control surfaces are formed by mutually facing wedge ring surfaces on the actuating part of the pump device on the one hand and on the hose sleeve on the other. Thus, a uniform force transmission from the control member can be ensured on the hose cuff, since the wedge ring surfaces lead to an interaction between the control member and hose sleeve over the respective total circumference. As a result, a gentle deformation of the hose cuff and thus reliable operation of the ventilation valve is ensured. The wedge ring surfaces of the hose cuff and the control member may be the same or deviating from each other in terms of a wedge angle relative to the pump axis, wherein the wedge ring surfaces preferably each face with its narrow side.

In a further embodiment of the invention, the control member or the venting valve is associated with a timer for the delayed opening or closing of the venting valve. As a result, it is advantageously possible to influence an opening time and an opening duration of the ventilation valve. In particular, a timing member may be realized by a relatively movable attachment of the control member to the operating member. In this case, a power transmission between the actuating part and the control member is provided for example via a damping device. It can thus be effected that the control member only follows a movement of the actuating part for actuating the pump device with a delay, whereby a control of the venting valve takes place later than in a rigid coupling between the actuating part and control member. The time delay element can also be designed so that, in addition or alternatively, a return stroke of the actuating part after execution of the pump stroke is transmitted to the control member only with a delay, so that the vent valve is temporarily still open, although the actuating member has already moved back in the direction of its rest position , Due to the changed opening time and the changed opening duration, in particular a particularly uniform inflow of ambient gas into the medium container can be achieved. This allows, for example, the use of a filter device which is provided as a germ barrier for the medium container. Such a filter device may possibly only allow a limited volume flow for the ambient air, which would not be sufficient without influencing the opening duration of the ventilation valve in order to bring about a complete pressure equalization by subsequent flow of ambient air through the filter device into the medium reservoir.

Fig. 1

in ebener Schnittdarstellung eine Dosiervorrichtung mit einem Steuerglied und einem Belüftungsventil,

Fig. 2

in ebener Schnittdarstellung eine Ausschnittvergrößerung der Dosiervorrichtung gemäß Fig. 1,

Fig. 3

eine weitere Ausführungsform einer Dosiervorrichtung in einem vergrößerten Ausschnitt, und

Fig. 4

die Ausführung nach Fig. 3 mit geöffnetem Belüftungsventil.

Further advantages and features of the invention will become apparent from the claims and from the following description of a preferred Embodiment of the invention, which is illustrated with reference to the drawings. Showing:

Fig. 1

in a planar sectional view of a metering device with a control member and a vent valve,

Fig. 2

in a planar sectional view of a detail enlargement of the metering device according to Fig. 1 .

Fig. 3

a further embodiment of a metering device in an enlarged section, and

Fig. 4

the execution after Fig. 3 with open vent valve.

The in the Fig. 1 Dosing device 1 shown has a pumping device 2 and a medium storage, not shown. The medium reservoir, which can be made in particular as a container made of plastic or glass, can be attached to an interface 3 of the pump device 2. For a secure connection between the medium reservoir and pumping device 2, a receiving sleeve 4 is provided at the interface 3, which allows a female thread 5 and a flat gasket 6 a positive and tight attachment of a correspondingly shaped neck portion of the medium reservoir. The receiving sleeve 4 is designed in one piece with a rotationally symmetrical guide sleeve 7, in which a lower part 8 of a piston pump 9 is received. A designed as a nose adapter upper part 10 of the piston pump 9 is received relatively movable to the lower part 8 in the guide sleeve 7. The upper part 10 is associated with a handle 11, a piston group 12 and a valve body 13.

The lower part 8 is designed substantially rotationally symmetrical and has an outer sleeve 14, which has a circumferential radial web 15 is connected to a pump section 16. On an end face of the pump section 16 facing the interface 3, an annular holding section 17 is provided which has a wedge geometry 18 at the front side. The holding portion 17 is provided for a positive reception of the flat gasket 6, which rests flat on the end face of the pump section 16. The wedge geometry 18 holds the gasket 6 in the intended position, even if no media storage is mounted. In the front side of the pump section 16, a centrally arranged passage bore 19 is provided, which is provided for receiving a not shown, projecting into the medium reservoir riser. Furthermore, an eccentrically arranged ventilation hole 20 is introduced in the end face of the pump section 16, which allows a receptacle of a filter device 21 and is provided for a communicating connection between the medium container and an environment of the pump device 1. The filter device 21 consists essentially of a rotationally symmetrical filter sleeve 22 having a through bore, and a filter membrane 23 which is received in the filter sleeve 22 so that it closes the through hole. The filter membrane 23 is made of a gas-permeable and liquid-barrier material and thus enables the retention of germs on a surface facing away from the medium storage and leakage of liquid and / or powdered Mediumbestanteilen from the media storage.

The vent hole 20 opens tangentially on an outer surface of the pump section 16 above an annular shoulder 24 in a gap 47 communicating communicates with the environment. The ventilation bore 20 is closed by a hose collar 25 resting on the annular shoulder 24 and elastically applied to the outer surface of the pump section. The hose cuff 25 is rotationally symmetrical, made of an elastic material, For example, an elastomer such as silicone or polyethylene produced and has a substantially L-shaped cross-section. In this case, a shorter leg of the L-shaped cross section is arranged radially and rests with its inner side on the cylindrical outer side of the pump section 16, while a medium storage facing end side of the shorter leg rests flat against the annular shoulder 24. On an inner side of the longer leg of the L-shaped cross section, a radially inwardly directed to the outside of the pump section 16 sealing lip 26 is provided, which also bears against the outside of the pump section 16. The sealing lip 26 has a small contact surface with respect to the pump section, so that even at a low contact force, which is caused by the elastic deformation of the hose sleeve 25, a high surface pressure on the inner surface of the sealing lip 26 is present. Thus, a particularly advantageous sealing effect of the hose sleeve 25 for the ventilation hole 20 can be achieved. In order to enable an advantageous sealing effect of the hose cuff 25, the pump section 16 has a diameter jump 27 approximately at half the height of the hose cuff 25. By the diameter jump 27 ensures that only the sealing lip 26 rests on the outside of the pump section 16 and can develop the desired sealing effect, while the rest of the longer leg of the L-shaped cross-section is free. At a side facing away from the medium storage end side of the hose sleeve 25 is a conical, designed as a wedge ring surface, circumferential control surface 28 is provided, wherein a wedge angle of the control surface 28 relative to a pump axis 29 is designed as an acute angle. The hose cuff 25 forms with the pump section 16 and the venting bore 20 provided therein the venting valve 44 of the metering device 1.

The pump section 16 is designed as a double sleeve in a region remote from the medium reservoir. Thereby limit an inner wall an outer sleeve 30 and an outer wall of an inner sleeve 31 an annular chamber 32, which serves as a cylinder for the piston pump 9. In this case, the outer sleeve 30 projects beyond the inner sleeve 31. The inner sleeve 31 forms the upper, the medium storage remote portion of the passage bore 19 and has in the region of the end face on a conical shape.

The piston group 12 is designed substantially as a one-piece, rotationally symmetrical component and has a piston sleeve 33 and a concentric with the piston sleeve 33 arranged piston punch 34. The piston ram 34 is provided at the end with a conical depression, which causes an increase in the elasticity in this area and allows an advantageous adaptation to the diameter of the through-hole 19. The piston sleeve 33 and the piston plunger 34 define a substantially annular piston chamber 35, which is formed corresponding to the annular chamber 32. In a starting position, as in the Fig. 1 is shown, the piston sleeve 33 protrudes into the outer sleeve 30, while the plunger 34 terminates at least approximately flush with an upper edge of the inner sleeve 31, but this does not touch, so that the passage bore 19 is not closed in the starting position and a connection with the not illustrated riser and thus allows the media storage. At the bottom of the piston chamber 35, an outlet bore 36 is provided eccentrically to the pump axis 29, which opens into a radially extending transverse bore 37. The transverse bore 37 connects to an annular gap 38 which is formed between the piston group 12, the valve body 13 and the upper part 10 and which opens into a nozzle opening 39, which is introduced into the upper part 10 and communicating with the environment. In the starting position of the Fig. 1 the nozzle opening 39 is held closed by the biased with a compression spring 46 valve body 13.

Between the upper part 10 and the lower part 8 designed as a compression spring coil spring 40 is provided which holds the upper part 10 in the starting position. The spiral spring 40 is supported on the shorter leg of the L-shaped hose sleeve 25 on the circumferential annular shoulder 24 of the lower part 8 and at its other end to an intermediate sleeve 41, which is received in the upper part 10 in a form-fitting manner. The intermediate sleeve 41 has a substantially hollow cylindrical cross section and is provided with a radially outwardly directed, circumferential support collar 42, which allows a positive support on an annular shoulder of the upper part 10. At a side facing away from the upper part 10 of the intermediate sleeve 41 is provided with a conical taper at an acute angle to the pump axis 29 running tapered ring surface which is formed as a corresponding control surface 43 to the control surface 28. The intermediate sleeve 41 represents the control member of the pumping device, which is attached to the executed as an operating part upper part 10.

Like in the Fig. 1 shown, a relative mobility of the upper part 10 relative to the lower part 8 is reached in the initial position by a Wegbegrenzung for which a circumferential, radially outwardly directed annular collar 43 is provided on the upper part, which in the initial position in a positive operative connection with a radially inward directed collar of the guide sleeve 7 is and slipping out of the upper part 10 from the lower part 8 is prevented. The piston sleeve 33, which enters into the annular chamber 32 during a pump stroke, limits the relative mobility during the actuation of the metering device. The pump stroke results according to Fig. 1 to L1. In contrast, the distance of the control surface 28 of the hose sleeve 25 relative to the control surface 43 of the intermediate sleeve L2. The distance L1 is greater than the distance L2, so that upon execution of a full pump stroke inevitably an actuation of the vent valve 44 by the designed as a control member intermediate sleeve 41 occurs.

On the upper part 8, the handle 11, which is rotationally symmetrical and has finger support surfaces 45, mounted in a form-fitting manner. The handle 11 slides on the outside of the guide sleeve 7 and thus stabilizes the lifting movement of the upper part 10 relative to the lower part eighth

For an actuation of the dosing device 1, an operator exerts opposite operating forces on the finger support surfaces 45 and on the bottom of the medium storage, not shown. As soon as the operating forces exceed a predetermined by a bias of the coil spring 40 force level, a movement of the upper part 10 and the associated components takes place. In this case, the piston group 12 slides with the piston sleeve 33 and the piston punch 34 in the annular chamber 32 and in the through-hole 19 a. The piston sleeve 33 forms with the annular chamber 32 an outer boundary for a medium volume. The piston plunger 34, which is flush in the starting position with the upper edge of the inner sleeve comes through the movement of the upper part 10 into contact with the provided in the inner sleeve 31 through-hole 19 and closes it, so that the annular chamber 32 and the piston sleeve 33 and the piston plunger 34 formed piston chamber 35 complete the medium volume. The trapped and set by the operating force under pressure medium volume can therefore escape only through the outlet bore 36, the transverse bore 37, the annular gap 38 and the nozzle opening 39. However, since the valve body 13 closes the nozzle opening, the medium volume must be placed under sufficient pressure to exert an opening force on the valve body 13 against the biased compression spring 46. This can be effected by increasing the operating force exerted by the operator, so that the medium volume is pressurized more and more and finally exerts the opening force on the valve body 13, so that an outflow into the environment is possible. This results in a pressure drop in the enclosed volume, which leads to a rapid movement of the piston group 12 in the direction of the medium reservoir. In the course of this movement, the control surface 43 of the intermediate sleeve 41 approaches the control surface 28 of the hose cuff 25. Finally, as in the Fig. 2 shown, a contact of the opposing control surfaces 28 and 43 wherein the longer leg of the L-shaped cross-section of the hose cuff 25 is urged radially outward by the wedge-shaped contour of the opposing control surfaces 28 and 43. As a result, the sealing lip 26 is lifted off the outer surface of the pump section 16 and releases the ventilation bore 20. Thus, an influx of ambient air through the vent hole 20 and the filter device 21 provided therein take place, so that a partial or complete pressure equalization between the environment and the medium storage is made possible. After completion of the medium discharge through the nozzle opening 39, the operator reduces the operating force again, so that the upper part 10 moves due to the deformed during the actuation process coil spring 40 back toward the starting position. In this case, the intermediate sleeve 41 also moves away from the hose cuff 25 so that the control surfaces 28 and 43 are no longer in contact with each other and the hose cuff 25 reseals the ventilation opening 20 due to its elasticity. Thus, no further gas exchange between the trapped in the medium storage volume and the environment take place.

Due to the forced actuation of the ventilation valve 44 via the intermediate sleeve 41, the elasticity of the hose cuff 25 can be selected so that leakage of volatile medium components from the medium reservoir can take place only at a high overpressure. This will ensure that the vent valve is closed under normal conditions of storage and use and thus no change in concentration of stored in the medium storage drug takes place.

In an embodiment, not shown, of the invention, the intermediate sleeve is relatively movably attached to the lower part to realize a time delay element. Opposite in the Fig. 1 and 2 illustrated embodiment, the coil spring for the provision of the upper part in the starting position is not supported on the intermediate sleeve, but directly on the upper part, while the intermediate sleeve is pressed against the upper part via a second, concentric to the coil spring provided compression spring. The compression spring is supported on the hose cuff and on the underside of the support collar. The intermediate sleeve is in deviation of the embodiment of Fig. 1 and 2 displaced relative to the upper part. An operating force exerted on the upper part can be positively introduced via the support collar into the intermediate sleeve. A displacement of the intermediate sleeve is as in the embodiment of Fig. 1 and 2 caused by a movement of the upper part in the direction of the medium storage. The intermediate sleeve can slide on the outside of the pump section to be moved from a starting position into an actuating position for the venting valve. In the actuation position, the control surfaces of the intermediate sleeve and the hose sleeve come into operative connection, wherein the sealing lip is urged radially outwards by the interaction of the wedge ring surfaces and thereby lifted off the surface of the pump portion. If the upper part moves back to the starting position after completion of the discharge process, the intermediate sleeve does not follow this movement immediately because there is no rigid coupling between upper part and intermediate sleeve. Rather, the intermediate sleeve is again pressed back into the starting position only by the spring force of the compression spring, which has been compressed during actuation, wherein this movement is carried out against a defined frictional force between the outside of the pump section and the inside of the intermediate sleeve occurs. The outside of the pump section and / or the inside of the intermediate sleeve are at least partially provided with a damping medium, for example a silicone coating, which slows down a sliding movement of the intermediate sleeve from the actuating position back to the starting position by the occurrence of corresponding frictional forces. This ensures that the intermediate sleeve moves back into the starting position slower than the upper part, so that the ventilation valve can also be opened when the upper part has already returned to the starting position.

The embodiment according to the Figures 3 and 4 essentially corresponds to the previously described embodiment of a metering device. Accordingly, the disclosure of the metering device according to the FIGS. 1 and 2 directed to avoid repetition. Hereinafter, the differences from the embodiment according to the FIGS. 1 and 2 exposed. For better clarity, functionally identical components are provided with the same reference numerals with the addition of the letter "a".

Significant difference in the embodiment according to the Figures 3 and 4 it is that there is not acted upon by the serving as a control member intermediate sleeve 41a, the venting valve in the form of the hose sleeve 25a with an outwardly opening radial component, but is displaced only axially downwards. In Fig. 3 the valve closing position of the hose cuff 25a is shown. In Fig. 4 is the valve opening position represents. There it can be seen that in the valve opening position, the tube sleeve 25a is elastically compressed and deformed, and is thus displaced axially with its sealing lip portion downwards. The corresponding axial load is effected by the impingement of the intermediate sleeve 41 a with its lower end face on a according to plane and relative to the pump axis radially oriented surface of the tube sleeve 25a. Due to the elastic compression of the hose cuff 25 a, a ventilation path B is released, which is closed in the unloaded and erected state of the hose cuff 25 a by its circumferential sealing lip ( Fig. 3 ). The in the Figures 3 and 4 21a designated filter device corresponds to the filter device 21 of the embodiment according to the FIGS. 1 and 2 , so that does not need to be discussed in detail.

Claims (6)

1. A metering device (1) for at least one medium, with a medium storage unit, and with a pumping system (2) connected to the medium storage unit, said medium storage unit or said pumping system comprising a venting valve (44) that is held in the closed position by elastic force, wherein a control member (41) is assigned to the venting valve, and wherein the control member opens the venting valve in the event of a pumping movement of the pumping system,
   characterized in that
   the venting valve is designed as a tubular cuff (25), which, coaxially with respect to the pump axis, encloses a rotationally symmetrical pump section (16), wherein the tubular cuff (25) and the control member are provided with mutually corresponding control surfaces (28, 43) that can be brought into contact with one another for a process of opening of the venting valve, wherein the control surfaces (28, 43) are oriented at an inclination with respect to the pump axis (29) in such a way that, during a pumping movement, a radial movement component directed outward from the pump axis is applied to the tubular cuff (25).
2. The metering device according to claim 1, characterized in that the control member is arranged on an actuating part (10) which belongs to the pumping system and which is movable in a reciprocating motion relative to the venting valve, and in that the venting valve, in the unloaded state of the pumping system, is arranged at an axial distance (L2) from the control member - relative to a pump axis - that is smaller than an actuating stroke of the actuating part (10).
3. The metering device according to claim 2, characterized in that the venting valve (25a) is arranged axially resilient between a valve opening position and a valve closing position, and in that the control member (41 a) moves the venting valve (25a) axially to the valve opening position.
4. The metering device according to claim 3, characterized in that the venting valve (25a) is axially elastically deformable, and in that the venting valve is returnable from the valve opening position to the valve closing position by the elastic restoring characteristics.
5. The metering device according to any one of the preceding claims, characterized in that the control surfaces (28, 43) are formed by mutually facing conical-ring surfaces arranged, on the one hand, on the actuating part (10) of the pumping system and, on the other hand, on the tubular cuff (25).
6. The metering device according to any one of the preceding claims, characterized in that a time control member is assigned to the control member or the venting valve for delayed opening or closing of the venting valve.

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