EP2203645A1

EP2203645A1 - Microdosing device for dosing very small amounts of a medium

Info

Publication number: EP2203645A1
Application number: EP08786456A
Authority: EP
Inventors: Ralf Reichenbach
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2007-09-25
Filing date: 2008-07-25
Publication date: 2010-07-07
Also published as: DE102007045637A1; US20100166585A1; WO2009040165A1

Abstract

The invention relates to a microdosing device for dosing very small quantities of a medium, having an inlet device (1), an outlet device (2), a pump device (3) and a media duct (15) which leads from the inlet device (1) to the outlet device (2), wherein the inlet device (1) has an inlet opening (4) and an inlet valve (5) with an inlet valve piston (6), the outlet device (2) has an outlet opening (7) and an outlet valve (8) with an outlet valve piston (9), and the pump device (3) has a pump piston (10). The inlet valve piston (6), the outlet valve piston (9) and the pump piston (10) are arranged on a common diaphragm layer (12). The microdosing device has the advantage that it can be produced in a simple and cost-effective manner.

Description

Microdosing device for dosing small amounts of a medium

State of the art

The invention relates to a microdosing device for dosing small quantities of a medium, comprising an emptying device, an outlet device and a pump device, wherein the inlet device comprises an inlet opening and an inlet valve with an inlet valve piston, the outlet device an outlet opening and an outlet valve with an outlet valve piston and the pumping device Pump piston has.

Microdosing have in various applications, such as in the medical technology field, a great importance and serve z. For continuous insulin administration in a diabetic patient. The smallest amounts of a medium must be precisely dosed and administered.

Various implementations of microdosing devices are known from the prior art. Most of these microdosage devices use silicon bulk micromechanics for structuring silicon or glass wafers, which are then usually joined together by bonding.

A microdosing device is known from DE 197 37 173 A1, which has a micro-diaphragm pump and a free-jet dosing device connected thereto. The micro-membrane pump and the free-jet dispenser are formed according to this construction in a common component, wherein these components are composed of a plurality of semiconductor layers. As an actual pump-active device, the micromembran pump has a pumping membrane which, by means of an actuator, is perpendicular to its initial position. level is deflectable. In this way, can be sucked by a separately trained Emiassventil medium from a reservoir and then passed through a likewise separately trained exhaust valve to the free jet dispenser.

This construction as well as other constructions known from the prior art are thus very complex, namely often have a large number of layers, so that the production is complicated and expensive. Furthermore, it is difficult to ensure the tightness of such Mikrodosiervorrichtungen, both the inlet side and the outlet side.

Disclosure of the invention

The microdosing device according to the invention has the advantage over that it can be produced easily and inexpensively.

According to the invention, this is achieved by a microdosing device for dosing small amounts of a medium, having an inlet device, an outlet device, a pumping device and a media channel leading from the inlet device to the outlet device, the inlet device having an inlet opening and an inlet valve with an inlet valve piston, the outlet device an outlet opening and an outlet valve having an outlet valve piston and the pumping means comprises a pumping piston, characterized in that the inlet valve piston, the outlet valve piston and the pump piston are provided on a common membrane layer.

According to the invention, only a single membrane layer is required, which acts as a membrane for both the inlet valve, the outlet valve and the pumping device. The fact that only one membrane layer is required, the production of the microdosing is much easier and it can be a compact design of the entire unit achieve.

In the case of the use according to the invention of a common membrane layer for the inlet valve, the outlet valve and the pump device, it is preferably provided that the inlet valve piston, the outlet valve piston and the pump piston are each arranged on mutually different regions of the membrane layer. This membrane layer with the devices arranged thereon represents the most stressed part of the microdosing device. This part is preferably produced by means of classical micromechanics from a composite of a substrate with a sacrificial layer and a functional layer. This composite preferably has an SOI wafer, a silicon substrate with SiCV sacrificial layer and an epitaxially grown polycrystalline (epipoly) Si functional layer or a silicon substrate with SiGe sacrificial layer and an epipoly-Si functional layer.

A preferred embodiment of the invention is that above the membrane layer, an upper cover layer and / or below the membrane layer, a lower cover layer

Cover layer is provided, wherein the upper cover layer and the lower cover layer are preferably made of a polymer substrate. In this way, the most heavily loaded part of the microdosing device according to the invention, namely the membrane with its devices, is realized from a mechanically high-quality material, while the upper cover layer, which preferably has the inlet opening and the outlet opening, and the lower cover layer, which are preferably together with the membrane forms the media channel, through which the medium from the inlet to the outlet device is conveyed, are made of substantially cheaper producible materials. Alternatively, structured glass, pyrex, quartz or silicon wafers are also possible for the upper cover layer and the lower cover layer. The

The individual layers are preferably joined by gluing or optionally by suitable wafer bonding processes.

It has previously been said that the inlet opening and the outlet opening are preferably provided on the upper cover layer. In a corresponding construction, it is further preferably provided that the inlet valve piston and the outlet valve piston are arranged between the upper cover layer and the membrane layer, so that the inlet opening and the outlet opening can be sealed by means of a movement of the membrane layer. In order to move the membrane layer accordingly, z. B. a pumping device associated pump actuator may be provided so that on the

Pump piston acts, which allows movement of the membrane in the pumping device perpendicular to its plane of extension upwards or downwards. This is associated with a pumping action, due to which medium can be sucked in through the inlet valve or ejected through the outlet valve, as described in detail below. - A -

It has also been said previously that, according to a preferred embodiment of the invention, a media channel is provided between the membrane layer and the lower cover layer, through which the medium can be requested from the inlet device to the outlet device. In such a construction, it is preferably further provided that the membrane layer in the region of the inlet valve and in the region of the outlet valve in each case has at least one passage opening for the passage of the medium from the region between the upper cover layer and the membrane layer into the media channel. This allows such an operation of the Mikrodosiervorrich- device, in which by a corresponding movement of the pump piston of the pumping device, the membrane layer in the pumping device is raised or depressed, which corresponds to an increase or decrease in the volume of the media channel, whereby at correspondingly open inlet valve or Outlet valve medium is sucked in via the inlet device, passes through the corresponding passage opening in the media channel and exits the media channel in an ejection process through the passage opening in the region of the outlet device, so that it expelled from the Mikrodosiervor- direction with appropriately opened outlet valve via the outlet opening can be.

In principle, the microdosing with all of their previously mentioned

Facilities be designed as a common entity. According to a preferred embodiment of the invention, however, it is provided that the inlet valve piston, the outlet valve piston and the pump piston are provided on the common membrane layer together with the upper cover layer as a removable unit in a housing, which in turn provides the lower cover layer. In other words, the combination unit comprising the inlet valve piston, the outlet valve piston, the pump piston and the common membrane layer can thus be provided as one-way device, which is arranged in a reusable housing which closes the disposable unit downwards by means of the lower cover layer, around the media channel to build. In this case, this housing can be made in different ways. According to a preferred embodiment of the invention, however, it is provided that it is produced by means of a cost-effective injection molding process.

Preferred developments of this housing are also that the housing has a preferably removable media reservoir. In this way, a modular Res system realized in which always only the components must be replaced or renewed, which are exhausted or used up. According to a preferred embodiment of the invention, it is further provided that the housing provides the pump actuator required for the pumping device. Furthermore, according to a preferred further development of the invention, the housing is provided with a preferably removable power supply, such as a battery.

In particular, it is preferred that the media reservoir and the pumping unit are designed as a removable total unit which is replaced as soon as the medium in the reservoir has been used up or expired / expired. Thus, a sterile packaged disposable unit may be provided, e.g. stored in the refrigerator with which the following changes can be made: open the housing, remove the old unit, sterilize and unpack and insert the new unit.

Furthermore, it is preferred that the housing has an electronic circuit with a programmable interface for programming at least one presetting of the microdosing device. In this way, z. B. individually adjustable for each application, which quantities of the medium to be dosed and administered at what times. Finally, according to a preferred embodiment of the invention, it is also provided that the housing has a sensor connection for connection to a sensor, according to the measured value of which the metering of the medium is controlled. This sensor connection can be configured wired or wireless.

For sucking the medium from a medium reservoir, it is generally the case that a negative pressure is generated in the medium channel by the pumping device, which is effected by moving the volume of the medium channel by moving the pump piston together with the membrane layer arranged in the region of the pumping device is increased to the top. In order to achieve a clear separation of the emissive process from the outlet process, which is essential for an accurate dose rate of the medium, it is provided according to a preferred embodiment of the invention that the outlet valve is self-locking in the media channel at a suppression. In addition, it can be provided according to a preferred embodiment of the invention that the inlet valve is self-locking at an overpressure in the media channel. In such an embodiment of the intake valve or the exhaust valve, there is the advantage that neither the inlet valve nor the exhaust valve active, z. By means of an ac- gate must be opened or closed, since the exhaust valve during the suction process, which is connected to a negative pressure in the media channel, is automatically closed and the inlet valve is also closed automatically at an overpressure, which prevails in a discharge operation.

If it has previously been said that there is a negative pressure or an overpressure in the media channel, so it is turned off on the pressure difference with respect to the area on the other side of the intake valve and the exhaust valve, ie z. B. in the media reservoir or in the discharge region of the microdosing.

The microdosing device described above is preferably used in medical technology, for. As in the already mentioned insulin administration, as well as the continuous local administration of analgesics. Further areas of application are in automation technology as pre- and control valves for larger valves. Furthermore, the possible applications in the field of bio / life science, especially in micro-analysis systems, called.

The invention will be described below with reference to preferred embodiments with reference to the drawings in detail. In the drawing show:

Fig. 1 is a schematic cross-sectional view with the three essential

Functional blocks of a microdosing device according to a preferred embodiment of the invention,

2 shows a schematic cross-sectional view of the microdosing device according to the preferred embodiment of the invention during the suction process,

3 is a schematic cross-sectional view of the micro-dosing device according to the preferred embodiment of the invention in the ejection process,

Fig. 4 is a schematic representation of the micro-dosing device according to the preferred embodiment of the invention as a combination of a disposable part in a reusable housing in the closed state and 5 is a schematic representation of the microdosing device according to the preferred embodiment of the invention as a combination of a disposable part in a reusable housing in the open state.

FIGS. 1 to 3 each show a schematic cross-sectional representation of a microdosing device according to a preferred exemplary embodiment of the invention. This microdosing device is used for dosing small quantities of a medium and has an inlet device 1, an outlet device 2 and a pumping device 3, which in FIG. 1, for the sake of clarity, are separated from one another by three

Function blocks are shown. In fact, according to the preferred embodiment of the invention, these three components of the microdosing device are manufactured directly as a coherent system on a common substrate, as will be explained below.

The inlet device 1 has an inlet opening 4 and an inlet valve 5 with an inlet valve piston 6. By analogy with this, the outlet device 2 has an outlet opening 7, an outlet valve 8 and an outlet valve piston 9. Between the inlet device 1 and the outlet device 2, the pumping device 3 is provided, which has a pump piston 10, which is associated with a pump actuator 11. As a pump actuator

11 is provided according to the presently described preferred embodiment of the invention, a piezo stack. However, other principles for the pump actuator 11 are usable, such as magnetic or hydrodynamic. Incidentally, a bending piezo can also be used. If the achievable forces and strokes are sufficient, a piezoelectric thin layer may also be provided for actuating the pump piston 10.

The inlet valve piston 6, the outlet valve piston 9 and the pump piston 10 are provided on a common membrane layer 12, which is formed as Epipoly-Si functional layer. Above this membrane layer 12, an upper cover layer 13 is formed, and below the membrane layer 12, a lower cover layer 14 is formed. According to the presently described preferred embodiment of the invention, the top cover layer 13 and the bottom cover layer 14 are both made of a polymer substrate. The upper cover layer 13 has the inlet opening 4 and the outlet opening 7, while by means of the lower cover layer 14 between the membrane Layer 12 and the lower cover layer 14, a media channel 15 is defined. Through this media channel 15 through the medium to be metered from the inlet device 1 to the outlet 2 is fordable. For this purpose, the membrane layer 12 has passage openings 16 in the region of the inlet device 1 and a passage opening 17 in the region of the outlet device 2. In the outlet valve piston 9 provided above the passage opening 17 in the region of the outlet device 2, a passage opening 31 is furthermore provided.

The supply of the medium takes place via a feed line 18 which leads to the inlet opening 4 of the inlet device 1. Following the outlet opening 7 in the outlet device 2, a discharge line 19 is provided to forward the ejected medium. As a result, the following operation of the microdosing device according to the preferred embodiment of the invention is possible:

As can be seen from Figure 2, by an upward movement of the pump actuator 11 of the

Pump piston 10 moves together with its associated region of the membrane layer 12 upwards, so that increases the volume of the media channel 15. In this way, the pressure in the media channel 15 decreases: Compared to the pressure in the supply line 18 creates a negative pressure. Therefore, the inlet valve 5 opens by the inlet valve piston 6 is moved downward, so that medium from the supply line 18, as indicated in Figure 2 by an arrow, via the through holes 16 and the opening annular gap in the membrane layer 12 in the Media channel can flow. Due to the negative pressure generated in the media channel 15 during the suction process, the outlet valve 8 locks: In the area of the outlet device 2, the membrane layer 12 is pressed against the outlet valve seat 30 provided below the outlet valve piston 9 on the lower cover layer 14 so that no medium escapes from the media channel 15 can.

To initiate the ejection process shown in FIG. 3, after filling the media channel 15 with the medium, the pump actuator 11 is moved downwards, so that the pump piston 10 presses the membrane layer 12 downwards on the upper side of the lower cover layer 14 in the area of the pumping device 3 , As a result of the overpressure generated in the media channel 15, the inlet valve 5 closes automatically and the outlet valve 8 is opened, so that the medium through the in the region of the outlet 2 in the Membrane layer 12 provided Durchgangsöffhung 17 and subsequently discharged through the outlet opening 7 above the outlet valve 8 in the discharge line 19.

According to the presently described preferred embodiment of the invention is now also provided that the upper cover layer 13 are provided together with the Emiassventilkolben 6, the Auslassventilkolben 9 and the pump piston 10 on the common membrane layer 12 as a removable unit 20 in an external housing 21. This is apparent from FIGS. 4 and 5. In this case, the housing 21 can be folded open, so that the removable unit 20 described above can be placed on the lower part 22 of the housing, which in turn thus forms the lower cover layer 14 of the micro-metering device. The removable unit 20 may thus be provided as a disposable part, which can be removed after its use from the reusable housing 21 and replaced with a new one. The sealing of the upper part 23 of the housing 21 relative to the removable unit 20 by means of O-ring seals 32. To open the housing 21, the upper part 23 and the lower part

22 pivotally attached to each other, for. B. by means of a film hinge 35. In the closed state, the upper part 23 and the lower part 22 at their respective end facing away from the film hinge by means of locking means 33, 34 attached to each other.

The upper part 23 of the housing 21 has, according to the presently described preferred first embodiment of the invention, a media reservoir 24 which is connected to the inlet device, so that from the media reservoir 24 medium to Emiasseinrichtung 1 out is feasible. If the medium provided in the media reservoir 24 is used up, the media reservoir 24 can be removed and exchanged for a new one.

Further, in the upper part 23 of the housing 21, a removable power supply 25 is provided in the form of a battery. The thus made available electrical energy is z. B. required for the pump actuator 11, which is also provided in the upper part 23 of the housing 21 and, as described above, acts on the pump piston 11 of the pumping device 3. In addition, in the upper part 23 of the housing 21, an electronic circuit 26 is provided with a programmable interface for programming at least one presetting of the micro-metering device, in the form of a micro-processor. As a result, a microdosing device is provided with the following advantages:

Expensive silicon is only used for the mechanically most important layers. As a result, the expensive processing of silicon is limited: There are only three micromechanical processing steps due, namely twice Trenchen and once the etching of a sacrificial layer.

Due to the cost-reducing use of inexpensive and easy-to-process poly substrates, namely in particular for the upper cover layer 13 and under cover layer 14, the entire device is very inexpensive and thus very competitive.

The size of the structures in conjunction with the planar technology also brings with it the possibility of using the thick-film technology, namely for applying z. B. special non-stick or sealing layers by screen printing in the pump and valve seat area.

Claims

claims

1. Microdosing device for dosing small quantities of a medium, with an emitter device (1), an outlet device (2), a pump device (3) and one of the inlet device (1) to the outlet device (2) leading media channel (15), wherein the inlet device (1) an inlet port (4) and an inlet valve (5) with an inlet valve piston (6), the outlet device (2) an outlet port (7) and an outlet valve (8) with an outlet valve piston (9) and the pumping device (3) Pump piston (10), characterized in that the inlet valve piston (6), the outlet valve piston (9) and the pump piston (10) on a common membrane layer (12) are provided.

2. microdosing device according to claim 1, characterized in that the membrane layer (12) is formed as a silicon functional layer.

3. microdosing device according to claim 1 or 2, characterized in that above the membrane layer (12) an upper cover layer (13) and / or below the membrane layer (12) a lower cover layer (14) is provided, wherein the upper cover layer (13) or the lower cover layer (14) is preferably made of a polymer substrate.

4. microdosing device according to claim 3, characterized in that between the lower cover layer (14) and the membrane layer (12) of the media channel (15) is formed.

5. microdosing device according to claim 3 or 4, characterized in that the inlet opening (4) and the outlet (7) in the upper cover layer (13) are provided and the inlet valve piston (6) and the outlet valve piston (9) between the upper cover layer (13 ) and the membrane layer (12) are arranged, so that the inlet opening (4) and the outlet opening (7) by means of a movement of the membrane layer (12) are sealable.

6. Mikrodosiervorrichtung according to any one of claims 3 to 5, characterized in that the membrane layer (12) in the region of the inlet valve (5) and in the region of the outlet valve (8) each have at least one Durchgangsöffhung (16, 17) for the passage of the medium from the area between the upper cover layer (13) and the

Membrane layer (12) in the media channel (15).

7. microdosing device according to one of claims 3 to 6, characterized in that the inlet valve piston (6), the outlet valve piston (9) and the pump piston (10) on the common membrane layer (12) together with the upper cover layer (13) as removable unit (20) are provided in a preferably produced by an injection molding process housing (21), which provides the lower cover layer (14).

8. microdosing device according to claim 7, characterized in that the

Housing (21) a preferably removable media reservoir (24) and / or a pump actuator (11) and / or a preferably removable power supply (25) and / or an electronic circuit (26) with a programmable interface for programming at least one default setting and / or a sensor connection for connection fertil with a sensor, according to the measured value, the dosage is controllable.

9. microdosing device according to claim 8, characterized in that the media reservoir (24) and the pumping unit (20) are formed as a removable total unit.

10. microdosing device according to one of claims 1 to 9, characterized in that the inlet valve (5) and / or the outlet valve (8) each have a sealing layer to improve the seal, wherein the sealing layer is preferably a soft and flexible material, such as a parylene or a silicone.