ES2229829A1 - High pressure microfluidic valve, has electrostatic actuator provided between pressure control units, chamber connected with pressure control units through inlet, and intermediate wafer and lower wafer formed with chamber - Google Patents

Abstract

The valve has a lower wafer (1), an intermediate wafer (2) and a top wafer (3) formed with a deep recess (4) that is protruded into a deformable stopper membrane (5). A fluid inlet hole (10) and a fluid outlet hole (11) are formed in the top wafer. The intermediate wafer and the lower wafer are formed with a chamber (6) that is connected with pressure control units through an inlet (7). An electrostatic actuator (9) is provided between the pressure control units.

Description

Microfluidic valve for high pressure.

Object of the invention

The present invention relates to a valve which is especially suitable for control and regulation of the flow of a liquid on a microscopic scale.

More specifically the valve that is recommended It has been specially designed to control liquids at high pressure and is structured in order to achieve great ease of maneuver in the opening and closing of the same, with an optimal functionality and minimal energy consumption.

The valve is of special application in microfluidic devices such as biological chips, reactors chemicals, genetic analysis, etc.

Background of the invention

In the field of practical application previously mentioned there are microfluidic valves with different types of action and with different geometries. In this sense there are valves with magnetic, electrostatic actuation, pneumatic, thermal or other types, and even valves with mixed performances.

These micro valves or microfluidic valves they are functionally correct when the pressure differences between the fluid inlet and outlet are relatively low, but when such differences are from various atmospheres they are not able to overcome them and, in most cases, the performance of the valve is aggressive with the workflow, especially when the means of action are electric.

Description of the invention

The microfluidic valve that the invention proposes, which can be placed in the field of valves with means of combined action, resolves fully satisfactorily the problem described above, allowing a correct valve operation with high pressures and without the valve is aggressive with the working fluid.

For this and more specifically the valve that it is recommended it is structured by three wafers, which can be obtained in different materials, as you will see more ahead, and that are mechanized or attacked with different reagents to give them the appropriate form, in accordance with their philosophy functional.

Specifically the bottom wafer meets the support function of the set, the intermediate forms the body of valve, including the shutter or mobile actuator, and the upper one contains the entrance and exit holes of the fluid, so that the flow rate of the fluid flow depends on the position of the membrane or shutter defined in the wafer intermediate.

Essentially it is expected that between the wafer bottom and the intermediate wafer shutter set a watertight chamber, equipped with a pressurized gas inlet hole, so that through this hole it can be supplied to the said chamber a pressure close to and slightly higher than the fluid inlet pressure to be controlled, so that the effort to perform by the actuator means is minimal, to meet those mentioned pressures close to the compensation situation.

In this way an easy drive is achieved of the membrane or plug, regardless of the pressure of the fluid to control and no matter how high, with a consumption minimum energy by said actuator.

The valve can be single or multiple, so that in the latter case a single lower wafer with a plurality of cameras properly interconnected with each other and to a source of single pressure, acts simultaneously on the membranes or shutters of the different valves.

Description of the drawings

To complement the description that is being performing and in order to help a better understanding of the characteristics of the invention, according to a preferred example of practical realization of it, is accompanied as part member of that description, a set of drawings where with illustrative and non-limiting nature, what has been represented next:

Figure 1.- Shows a representation schematic side elevation and section of a valve microfluidic for high pressure performed according to the object of the present invention.

Figure 2.- Shows, according to a representation similar to that of figure 1, a variant embodiment in which The valve is multiple.

Preferred Embodiment of the Invention

In view of the figures outlined and especially from figure 1, it can be seen as the valve that It is recommended to be constituted by three wafers (1), (2) and (3), rigid and tightly joined together by any procedure conventional suitable, such as by anodic bonding, chemical soldier, gaskets or any other means that I guarantee this tightness.

The intermediate wafer (2) is affected on your face faced with the intermediate wafer (1) by a wide recess (4), which in the practical example of the aforementioned figure 1 adopts a conical trunk configuration, but that can adopt any other appropriate configuration without affecting the essence of the invention, depth reduction in it for that at the bottom a membrane (5) thick is established small enough to be easily deformable

This recess (4) can be obtained by means of a doping operation, complemented by an anisotropic attack by its other side, which reduces the wafer thickness of this area until the ideal dimensions, of only a few microns, compared to hundreds of microns that said membrane or obturator (5) can present in diameter.

The recess (4) of the intermediate wafer (2) has as a complementary purpose to establish between these two wafers a chamber (6), communicated with the outside through a hole (7), to supply said chamber (6) with a predetermined pressure, which in turn it will be supplied to the membrane or obturator (5).

In addition, it is expected that the wafer lower (1) present in its zone of confrontation with the recess (4) a protuberance (8) in which the actuator means (9) is established, such as an electrode, in order for it to be close enough to the membrane (5), to act easily on it.

As a complement to the structure described, the upper wafer (3) will have at least one inlet hole (10) for the fluid to be controlled, and one or more outlet holes (11) for said fluid, so that the membrane (5) closes all these holes in valve closure situation, when pressed against the internal face of the wafer (3), and puts them in communication when undergoes a deformation when dragged by the actuator mechanism (9).

The bottom wafer (3), in support functions for the valve as a whole, it will be obtained based on a rigid material such as metal, silicon or other, the intermediate wafer (2) may be of the same nature, and the upper wafer (3), also of a rigid nature may be glass, silicon or other Similar performance material.

According to this structuring, the Valve operation is as follows:

Taking into account that the fluid to be controlled supplies the inlet port (10) with a pressure P1, to the chamber (6) and through its entrance hole (7) a pressure P2 greater than the mentioned pressure P1 so that the valve is will keep permanently closed, regardless of tension that is applied to the actuator element (9) that will be insufficient to overcome the difference between pressures P2 and P1. However, if the chamber (6) applies a pressure P2 slightly higher than the P1 pressure of the fluid to be controlled, the force produced by the actuator (9), for example an electrostatic actuator, will be enough to vary the position of the membrane (5), opening the valve.

However, the electrostatic force of actuator (9) must only overcome the force due to the difference in pressures, so that the power of said actuator is minimal, and also minimizes its energy consumption, despite the fact that the valve is working with very high P1 pressures, of the order of tens of atmospheres

This valve structuring allows, in addition, use chamber pressure (6) as safety means to close the valve instantly, with independence of the control voltage, in case this is necessary.

The valve basically has two states of balance, completely open and completely closed, but can also be used to regulate the flow rate through succession adequate opening and closing intervals.

In either of the two resting states the The energy consumption of the valve is theoretically zero, the consumption occurring only during switching, which equivalent to the normal operation of the valve consumption Total of it is very small, as already noted with anteriority.

Finally and in accordance with the representation of Figure 2, it is feasible to make a multiple valve, specifically a double valve in the example of said figure, in which on a lower wafer (1 ') several chambers are established (6), (6 ') ..., corresponding to respective valve units, with identical structuring as in the previous case, but in this case with the proviso that the different cameras (6), (6 ') will be related to each other through pipes communication (12) that allow to establish the same pressure in all the cameras (6), (6 ') from a power supply only.

Claims (4)

1. Microfluidic valve for high pressure, characterized by being constituted by three rigid wafers and tightly joined together, a lower wafer (1) depending on the support of the assembly, an intermediate wafer (2) equipped with a deep recess (4) determining of a membrane or obturator (5) of reduced thickness, and an upper wafer (3) which, in a situation of confrontation with the membrane (5), incorporates at least one orifice (10) of fluid inlet to be controlled and one or more exit holes (11) for said fluid, it being provided that between the intermediate wafer (2) and the lower wafer (1) a chamber (6) is provided with at least one pressurization hole (7), in order to the pressure P2 in said chamber (6) is substantially close to the high pressure P1 in the inlet port (10) of the fluid to be controlled. 2. Microfluidic valve for high pressure, according to claim 1, characterized in that the lower wafer (1) has, in its area of recess (4) of the intermediate wafer (2), a protuberance (8) on which it is located the valve actuator means (9), in order that it is substantially close to the membrane or plug (5). 3. Microfluidic valve for high pressure, according to previous claims, characterized in that the wafers (1), (2) and (3) are made of a rigid material, such as metal, silicon, glass or other. 4. Microfluidic valve for high pressure, according to previous claims, characterized in that on the same lower wafer (1), with a repetitive structure, several intermediate wafers (2) and upper wafers (3) are established to configure a multiple valve, in the that the pressure chambers (6), (6 '), ..., are communicated with each other to act simultaneously on all of them.