EP2321653A2

EP2321653A2 - Pressure control member, in particular a ventilating valve for ventilating a microdispenser

Info

Publication number: EP2321653A2
Application number: EP09777971A
Authority: EP
Inventors: Christian Wurzel
Original assignee: Scienion GmbH
Current assignee: Scienion GmbH
Priority date: 2008-09-02
Filing date: 2009-08-19
Publication date: 2011-05-18
Also published as: WO2010025826A2; WO2010025826A3; DE102008045423A1

Abstract

Disclosed is a pressure control member (1), in particular a ventilating valve for ventilating a microdispenser, having an inlet for feeding a fluid and an outlet for discharging the fluid, wherein the pressure control member (1) adjusts a specified holding pressure at the outlet, while the holding pressure at the outlet is less than the pressure at the inlet by a specified pressure difference.

Description

DESCRIPTION

Pressure actuator, in particular

Ventilation valve for aeration of a microdispenser

The invention relates to a pressure actuator, in particular a vent valve for venting a microdispenser.

WO 2006/128662 A1 discloses microdispensers which can be used for dispensing microdrops. The dispensing process is effected by a piezoelectric actuator which compresses the sample container and thereby ejects microdrops through a nozzle from the microdispenser. It is important that there is a negative pressure in the sample container of the microdispenser. This prevents the sample liquid from simply escaping through the nozzle from the sample container of the microdispenser, which is why the required underpressure is also referred to as holding pressure. However, the holding pressure in the sample container always decreases with each dispensing operation in accordance with the amount of liquid ejected, whereby the dispensing operation can be hindered. It is therefore desirable to set the holding pressure in the sample container as accurately as possible so that on the one hand the dispensing process is not hindered by too great a negative pressure, but on the other hand the holding pressure is sufficiently low to prevent the sample liquid from flowing out of the sample container.

The invention is therefore an object of the invention to provide a suitable pressure actuator for adjusting the holding pressure in such a microdispenser. This object is achieved by an inventive pressure actuator according to the main claim.

The invention comprises a pressure actuator having an inlet for supplying a fluid (e.g., ambient air) and an outlet for discharging the fluid, the pressure actuator adjusting at the outlet a predetermined holding pressure which is smaller than the pressure at the inlet by a predetermined pressure difference.

When using the pressure actuator according to the invention for the ventilation of a microdispenser, the inlet of the pressure actuator is usually connected to the ambient atmosphere, while the outlet of the pressure actuator opens into the sample container of the microdispenser.

However, the invention is not limited to the use of the pressure actuator as a vent valve in a microdispenser. Rather, the invention also claims protection for the use of the pressure actuator according to the invention in other applications, for example in an inkjet printer, a pump, a dosing system, an analysis system or diagnostic equipment.

Accordingly, the pressure actuator according to the invention is not only suitable for the passage of air, but also allows the passage of other gaseous or liquid fluids.

In a variant of the invention, the pressure actuator is an active valve, in which the valve position is adjustable by an actuator, wherein the actuator is preferably an electromechanical actuator, such as a piezoelectric actuator or a magnetic actuator. The actuator can therefore choose the valve open or close, whereby intermediate positions are possible.

In contrast, in another variant of the invention, the pressure actuator is a passive valve in which the valve position is determined solely by the pressure at the outlet and the pressure at the inlet. Preferably, the valve opens when the holding pressure at the outlet relative to the pressure at the inlet below a predetermined desired value, so that inflowing fluid brings the holding pressure back to the predetermined desired value. The pressure actuator according to the invention can therefore also be designed as a check valve.

In one embodiment of the invention, the pressure actuator has a tube connecting the inlet of the pressure actuator with the outlet of the pressure actuator, wherein in the tube an elastic valve membrane is used, which can be deflected axially between different positions. Preferably, the valve diaphragm is in the neutral position

(i.e., without an axial deflection) closed and opened in a deflected position, wherein the deflection of the valve diaphragm is preferably from the inlet side to the outlet side.

For this purpose, the valve membrane preferably has a breakthrough, wherein the breakthrough in the neutral position of the valve diaphragm closes automatically due to the elasticity of the valve membrane, while the breakthrough opens in the deflected valve position due to the deflection-induced deformation of the valve diaphragm.

For example, the breakthrough in the valve membrane may be slot-shaped or punctiform, but others are also Shapes of breakthroughs in the valve diaphragm possible. The decisive factor is that the opening in the valve diaphragm automatically closes or opens depending on the position of the valve diaphragm.

In a preferred embodiment, the valve membrane is multi-layered and has at least a first layer and a second layer. The first layer is permeable to gas, wherein the breakthrough in the valve membrane does not pass through the first layer. On the other hand, the second layer is gas-tight, with the aperture in the valve membrane passing through the second gas-tight layer.

It has already been mentioned above that the pressure actuator can be a passive valve, the deflection of the valve diaphragm being effected exclusively by the pressure difference between inlet and outlet. Alternatively, however, it is also possible for an actuator (for example a piezoactuator) to be provided for deflecting the valve membrane, which acts radially from the outside on the valve membrane and radially compresses the valve diaphragm and thereby axially deflects it. For example, the tube, in which the valve membrane is inserted, have an elastic wall which is cuff-shaped surrounded by the actuator, so that the actuator presses radially from the outside to the wall of the tube and thus compresses the valve membrane inserted into the tube and thereby axially deflects.

In another embodiment of the invention, the pressure actuator on the other hand, on the outlet side, a pipe piece, in which an elastic shut-off (eg, a unilaterally open hose piece) is inserted. In the closed state, the residual stress of the shut-off seal the pipe piece, so that the inlet side no fluid (eg air) in the pipe section can penetrate. In the open state, however, the shut-off body releases an annular gap between the shut-off body and the inner wall of the pipe section when the pressure at the outlet falls below the holding pressure and / or when an actuator compresses the pipe section.

The shut-off body is preferably a hose which is open at one end and is inserted with its open end into the pipe section, so that the hose, which is open on one side, abuts against the inner wall of the pipe section with its outer jacket surface and thereby seals the pipe section.

However, there is also the alternative possibility that the shut-off body is an elastic rod or an elastic ball, which are inserted into the open pipe piece and depending on the valve position seal the pipe section or release an annular gap.

Preferably, the pipe piece and the shut-off body have a different elasticity, wherein the pipe piece is preferably substantially rigid, while the shut-off body is elastic.

In a variant of this embodiment, both the pipe section and the shut-off body are elastic, but have a different deformation behavior. In this variant, an actuator is provided, which presses radially from the outside on the elastic pipe section and the pipe section and thus the shut-off differently deformed thereby creating a gap between the pipe section and the shut-off, by the fluid (eg ambient air) from the inlet can get to the outlet. In a further embodiment of the invention, however, the pressure actuator on a capillary, which connects the inlet to the outlet and contains a liquid column, wherein the holding pressure at the outlet side is determined by the capillary action of the capillary. Thus, the capillary action pulls the liquid column in the capillary toward the inlet, creating a vacuum on the outlet side.

The capillary can in this case have a coating which influences the capillary action, wherein the coating of the capillary can be designed such that the capillary action increases continuously or in steps over the length of the capillary from the inlet to the outlet or from the outlet to the inlet or decreases.

In addition, the capillary may have an internal cross-section which is substantially constant over the length of the capillary.

Alternatively, there is the possibility that the capillary has an internal cross-section which decreases continuously or in steps over the length of the capillary from the outlet to the inlet or from the inlet to the outlet.

In addition, in this embodiment, there is the possibility that a frit is arranged at the outlet end of the capillary to facilitate tearing of small air bubbles.

It should also be mentioned that the inner diameter of the capillary is preferably in the range of 1 μm to 3 cm, wherein different partial regions are possible within this interval. However, the invention includes not only the pressure actuator according to the invention described above, but also a microdispenser with such a pressure actuator for aerating the Mikrodispensers.

Such a microdispenser is described, for example, in the aforementioned patent application WO 2006/128662 A1, so that the content of this patent application is fully attributable to the present description.

Other advantageous development of the invention are characterized in dependent claims or are described below with the description of preferred embodiments of the invention düng with reference to the figures. Show it:

FIG. 1A shows a plan view and a cross-sectional view of a valve diaphragm of a valve according to the invention in the closed state,

FIG. 1B shows a longitudinal section through the valve according to the invention with the closed valve membrane according to FIG.

FIG. 1C shows the valve membrane from FIGS. 1A and 1B in the opened state,

FIG. 1 shows the longitudinal section from FIG. 1B in the opened state of the valve membrane,

Figure IE is a cross-sectional view of an inventive

Mikrodispensers with the valve according to the figures IA to IE, FIG. 2A shows a modification of the exemplary embodiment from FIGS. 1A to IE with an additional piezoactuator surrounding the tube with the valve membrane in the manner of a sleeve,

FIG. 2B shows the embodiment according to FIG. 2A with radially compressed actuator and deflected valve membrane,

FIG. 3A shows a further exemplary embodiment of a valve according to the invention with a flexible hose piece open on one side as a valve element,

FIG. 3B shows the embodiment according to FIG. 3A with an open valve position,

FIG. 3C shows a microdispenser with a ventilation valve according to FIGS. 3A and 3B,

4A shows a modification of the embodiment according to FIGS. 3A and 3B with an additional piezoactuator for adjusting the valve position, FIG.

FIG. 4B shows the embodiment according to FIG. 4A in the opened state,

Figure 5 shows another embodiment of a Mikrodispensers invention, in which the holding pressure is adjusted by a capillary.

FIG. 6A shows a modification of the embodiment according to FIGS. 1A-1D in the closed state,

FIG. 6B shows the embodiment according to FIG. 6A in the opened state, FIG. 7A shows a modification of the embodiment according to FIGS. 1A-1D in the closed state,

FIG. 7B shows the embodiment according to FIG. 7A in the opened state.

Figures IA to ID show a first embodiment of a ventilation valve 1 according to the invention, which can be used for ventilation of the Mikrodispensers 2 shown in Figure IE.

The ventilation valve 1 essentially consists of a valve membrane 3, which is inserted into a pipe section 4, whereby the pipe section 4 is the wall of a sample reservoir 5 of the microdispenser 2.

The valve membrane 3 in this case has a slot-shaped opening 6, which opens or closes in dependence on the deformation of the valve membrane 3.

Thus, FIGS. 1A and 1B show a neutral position of the valve membrane 3, in which the valve membrane 3 is not axially deflected, so that the slot-shaped opening 6 in the valve membrane 3 automatically closes due to the elasticity of the valve membrane 3.

The figures IC and ID, however, show an axially deflected position of the valve membrane 3, in which the slot-shaped opening 6 opens.

In addition to the representation in FIG. IE, it should be mentioned that the microdispenser 2 largely corresponds to the microdispenser described in the already mentioned patent application WO 2006/128662 A1, so that this patent application is to be fully attributed to the present description.

It should be mentioned at this point only that the microdispenser 2 for ejecting microdroplets 7 has a piezoelectric actuator 8, which surrounds the sample reservoir 5 in the area of a constriction 9 in the manner of a sleeve and thereby in a sample container 10 in the front region of the microdispenser 2 a pressure wave which causes the microdrops 7 to be ejected through a nozzle 11.

The exemplary embodiment according to FIGS. 2A and 2B largely corresponds to the exemplary embodiment described above and illustrated in FIGS. 1A to 1U, so that in order to avoid repetition of the above

Description is made, with the same reference numerals are used for corresponding details below.

A peculiarity of this embodiment is that the pipe section 4 in the area of the valve membrane 3 is surrounded on the outside cuff-shaped by an electromechanical actuator 12 which can radially compress the pipe section 4 depending on its electrical activation, which causes a corresponding axial deflection of the valve membrane 3. acts. In this embodiment, therefore, it is an active valve, in which the valve position is determined not only by the pressure conditions at the inlet and at the outlet of the valve, but by the activation of the actuator 12th

Figures 3A and 3B show another embodiment of a ventilation valve 13 according to the invention, which can be used for ventilation of the microdispenser 2, as shown in Figure 3C can be seen. The ventilation valve 13 again has a rigid pipe section 14 into which an elastic hose section 15 open at one end and closed at one end is inserted with its open end, wherein the outer jacket surface of the hose section 15 on the inner wall of the pipe section 14 due to the inherent elasticity of the hose section 15 is applied and thereby seals this.

On the other hand, FIG. 3B shows the opened state of the venting valve 13, wherein the negative pressure in the pipe section 14 causes the wall of the elastic hose section 15 to lift off the inner wall of the pipe section 14, thereby releasing an annular gap between the hose section 15 and the pipe section 14.

FIGS. 4A and 4B show a modification of the exemplary embodiment according to FIGS. 3A and 3B, this modification being largely identical to the exemplary embodiment described above, so that reference is made to the above description in order to avoid repetition.

A special feature of this embodiment is that the pipe section 14 is surrounded on the outside by an actuator 16, which can compress the pipe section 14 and thus also the hose piece 15. The tube piece 14 and the tube piece 15 in this case have a different deformation behavior, so that a compression of the tube piece 14 by the actuator 16 results in the fact that between the tube piece 15 and the tube piece 14 gas passages form, can pass through the gas.

FIG. 5 shows a further exemplary embodiment of a microdispenser 2 according to the invention, this exemplary embodiment play largely in accordance with the embodiments shown in FIGS. IE and 3C, so that in order to avoid repetition, reference is made to the above description, the same reference numerals being used for corresponding details in the following.

A special feature of this embodiment is that a liquid container 17 is connected to the sample reservoir 5, in which a capillary 18 is arranged, wherein in the capillary 18 is a liquid column. The capillary action in the capillary 18 in this case causes the liquid column in the capillary 18 to be pulled upward, as a result of which a negative pressure is created in the sample reservoir 5.

The exemplary embodiment according to FIGS. 6A and 6B corresponds largely to the exemplary embodiment described above and illustrated in FIGS. 1A to 1U, so that reference is made to the above description to avoid repetition, the same reference numerals being used for corresponding details below.

A special feature of this embodiment is that on the inlet side immediately behind the Ventilmemb- 3 a rigid support plate 19 is arranged, which has an opening in the center. The holding plate 19 holds the valve membrane 3 in the closed state, since the valve membrane 3 then rests on the holding plate 19.

In addition, in the pipe section 4 upstream of the

Holding plate 19 and the valve diaphragm 3, a filter 20 is arranged. The embodiment according to FIGS. 7A and 7B corresponds largely to the exemplary embodiment described above and illustrated in FIGS. 1A to 1U, so that reference is made to the above description to avoid repetition, the same reference numbers being used for corresponding details in the following.

A special feature here is that the hose piece 15 always seals the pipe piece 14, i. regardless of the pressure conditions.

However, located in the wall of the pipe section 14 has a bore 21 through which ambient air in the direction of arrow can enter into the interior of the pipe section 14 when the hose piece 14 - as shown in Figure 7B - due to

Pressure conditions is lifted inward from the inner wall of the pipe section 14 and then the bore 21 releases.

The invention is not limited to the preferred embodiments described above. Rather, a variety of variants and modifications is possible, which also make use of the inventive idea and therefore fall within the scope.

List of reference numbers:

1 ventilation valve

2 microdispensers

3 valve membrane

4 pipe piece

5 sample reservoir

6 breakthrough

7 microdrops

8 piezoelectric actuator

9 bottleneck

10 sample containers

11 nozzle

12 actor

13 ventilation valve

14 pipe section

15 piece of hose

16 actor

17 liquid container

18 capillaries

19 retaining plate

20 filters

21 hole

Claims

A pressure actuator (1; 13), in particular a vent valve for ventilating a microdispenser, having an inlet for supplying a fluid and an outlet for dispensing the fluid, characterized in that the pressure actuator (1; 13) sets a predetermined holding pressure at the outlet, wherein the holding pressure at the outlet is smaller than the pressure at the inlet by a predetermined pressure difference.

2. Pressure actuator (1, 13) according to claim 1, characterized in that a) that the pressure actuator (1, 13) is an active valve, wherein the valve position by an actuator (8;

12; 16), or b) that the pressure actuator (1; 13) is a passive valve in which the valve position is determined solely by the pressure at the outlet and the pressure at the inlet.

3. Pressure actuator (1) according to one of the preceding claims, characterized by a) a tube (4) which connects the inlet of the pressure actuator (1) with the outlet of the pressure actuator (1), and b) an elastic valve membrane (3), which is inserted into the tube (4) and can be deflected between a closed neutral position and an open valve position.

4. Pressure actuator (1) according to claim 3, characterized in that the valve membrane (3) has an opening (6), wherein the opening (6) in the neutral position ment of the valve diaphragm (3) due to the elasticity of the valve diaphragm (3) closes automatically, while the opening (6) opens in the deflected valve position due to the deflection of the valve diaphragm (3).

5. Pressure actuator (1) according to claim 3, characterized in, a) that the valve membrane (3) is two-layered or multi-layered and has at least a first layer and a ne second layer, and b) that the first layer is fluid-permeable, in particular gas-permeable wherein the opening (6) in the valve membrane (3) does not pass through the first layer, and c) that the second layer is fluid-tight, in particular gas-tight, whereby the opening (6) in the valve membrane (3) passes through the second layer goes through it.

6. Pressure actuator (1) according to claim 4 or 5, character- ized in that the opening (6) in the valve diaphragm

(3) is slit-shaped or punctiform.

7. Pressure actuator (1) according to any one of claims 4 to 6, characterized by an actuator (12) which acts radially on the valve diaphragm (3) and the valve diaphragm (3) radially compresses and thereby axially deflects.

8. Pressure actuator (13) according to claim 1 or 2, characterized by a) that the pressure actuator (13) on the outlet side a pipe section (14), b) that the pressure actuator (13) has an elastic shut-off body (15) in the pipe section (14) is inserted, c) that the residual stress of the shut-off (15) the pipe section (14) seals, d) that the shut-off (15) an annular gap between the shut-off (15) and the inner wall of the pipe section (14) releases when the pressure at the outlet of the Holding pressure below and / or if an actuator (12) compresses the pipe section (14).

9. Pressure actuator (13) according to claim 8, characterized in that a) that the shut-off body (15) is a unilaterally open piece of hose, which is inserted with its open end in the pipe section (14), or b) that the shut-off body is a rod c) that the shut-off body is an elastic ball.

10. Pressure actuator (13) according to claim 8 or 9, characterized in that a) that the pipe section (14) and the shut-off body (15) have a different elasticity, and / or b) that the pipe section (14) is substantially rigid, while the shut-off body (15) is elastic.

11. Pressure actuator (13) according to claim 10, characterized in that a) that both the pipe section (14) and the shut-off body (15) are elastic, but have a different deformation behavior, and b) that an actuator (12) is provided the radially from the outside presses on the pipe section (14) and the pipe section (14) and the shut-off (15) thereby deformed differently, whereby a gap between the pipe section (14) and the shut-off body (15) is formed.

12. Pressure actuator according to claim 1 or 2, characterized by a capillary (18) which connects the inlet to the outlet and contains a liquid column, wherein the holding pressure is determined by the capillary action of the capillary (18).

13. Pressure actuator according to claim 12, characterized in that a) that the capillary (18) has a coating which influences the capillary action, and / or b) that the coating of the capillary (18) is formed so that the capillary action over the length the capillary (18) increases or decreases continuously from the inlet to the outlet or from the outlet to the inlet, or in leaps.

14. Pressure actuator according to claim 12 or 13, characterized in that a) that the capillary (18) has an inner cross section which is substantially constant over the length of the capillary (18), or b) that the capillary (18) has an inner cross section which decreases continuously or in steps over the length of the capillary (18) from the outlet to the inlet or from the inlet to the outlet.

15. Pressure actuator according to one of claims 12 to 14, characterized by a frit at the outlet end of the capillary (18) to facilitate tearing small air bubbles.

16. Pressure actuator according to one of claims 12 to 15, characterized in that a) that the inner diameter of the capillary (18) is greater than 1 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 100 μm, 500 μm or 1 mm, and / or b) that the inner diameter of the capillary (18) is less than 3cm, 2cm, learning, 5mm, 2mm, 1mm, 500μm or 200μm.

17. Microdispenser (2) for dispensing a liquid sample, characterized by a pressure actuator (1; 13) according to one of the preceding claims for adjusting the holding pressure in the microdispenser (2).

18. microdispenser (2) according to claim 17, characterized by a) a sample container (10) for receiving the liquid sample, b) a nozzle (11) for dropwise delivery of the in the sample container (10) located sample, c) an integrated sample reservoir (5) in order to be able to deliver a plurality of sample droplets in succession without a refill, d) wherein the pressure actuator (1; 13) adjusts the holding pressure in the sample container (10) and / or in the sample reservoir (5).

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