CN211875267U

CN211875267U - Low-threshold constant-flow micro valve

Info

Publication number: CN211875267U
Application number: CN201922267810.4U
Authority: CN
Inventors: 张晨; 张鑫杰; 张文龙
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-12-17
Filing date: 2019-12-17
Publication date: 2020-11-06
Anticipated expiration: 2029-12-17

Abstract

The utility model discloses a low threshold value constant flow microvalve, including valve body, entry hydraulic reservoir, film, overflow hole, flow control chamber and fluid outlet. The inlet liquid storage tank is separated from the flow regulating cavity by a film and is communicated with the flow regulating cavity through an overflow hole; the thin film is a high-elasticity deformable film and can elastically deform towards the direction of the flow regulating cavity under the action of fluid pressure; the inner surface of the flow regulating cavity is a smooth curved surface, and the bottom of the flow regulating cavity is communicated with the fluid outlet. The utility model provides a low threshold value constant flow microvalve's flow regulation and control principle produces elastic deformation for utilizing the film to receive fluid pressure effect to act on, and the intracavity fluid is transferred in the extrusion, changes the flow resistance and the real-time compensation entry fluid pressure fluctuation of microvalve to realize the constant flow regulation and control. The micro valve has extremely low threshold pressure, so that the micro valve can be integrated with most micro-fluidic chips, and the application field of the micro valve is greatly expanded.

Description

Low-threshold constant-flow micro valve

Technical Field

The utility model relates to a micro-fluidic chip field, concretely relates to can be used to automatic accurate low threshold value constant flow microvalve of regulating and control microfluid flow.

Background

With the development of micro-nano manufacturing technology, the micro-fluidic valve has played an important role as a micro-scale control element in the fields of structure and chemistry and biology, gene sequencing, single cell analysis and the like. The micro-fluidic flow regulating valve can accurately regulate and control the flow, meets the requirement of precise micro-fluidic control, and has wide application requirements in the fields of precise drug delivery systems, nucleic acid detection, cell sorting and the like.

The existing micro-fluidic flow regulating valve is mainly divided into an active flow regulating valve and a passive flow regulating valve. The active flow regulating valve mainly regulates the flow by an additional control element, and has the advantages of high response speed of flow regulation and control and capability of realizing complex fluid control. However, since the valve needs to be operated by an external element, it consumes additional energy and is not easy to be miniaturized. Compared with an active flow regulating valve, the flow regulating principle of the passive flow regulating valve is simpler, the passive flow regulating valve does not need external control excitation, can automatically regulate the flow only by depending on the change of the structure of the passive flow regulating valve along with an external driving source, and does not consume extra energy, so the passive flow regulating valve has more advantages in the application of an integrated miniaturized system. The passive flow regulating valves reported at present can be divided into single-membrane valves and double-membrane valves according to the structure. The single-membrane valve realizes flow regulation by changing the flow resistance of a flow channel of the single-membrane valve through the deformation of one layer of elastic membrane by fluid pressure, has higher threshold pressure (more than 50kPa) required by reaching constant flow control, and is not easy to integrate with a micro-power driving device (such as a micropump) with low pressure. The double membrane valve has two layers of elastic membranes, the threshold pressure required to achieve constant flow regulation is only 25 kPa. However, because the source pressure of most micropower-driven devices is within 20kPa, it is difficult for a double membrane valve to meet the general requirements of integration with micropower-driven devices. Therefore, there is a need to develop a microfluidic passive flow control valve with low threshold pressure to achieve its effective integration with micropower driving device, and ultimately provide technical support for making low cost, portable drug delivery systems, microchip laboratories and point-of-care instrumentation.

SUMMERY OF THE UTILITY MODEL

Utility model purpose: in order to overcome the defects existing in the prior art, the utility model provides a low threshold value constant flow micro valve. The valve body has the advantages of small volume, easy integration, low threshold pressure and wide flow regulation range, and can meet the integration requirements of most micro-fluidic chips.

In order to achieve the above object, the utility model adopts the following technical scheme:

a low-threshold constant-flow micro valve comprises a valve body, an inlet liquid storage pool, a film, an overflow hole, a flow regulating cavity and a fluid outlet;

an inlet liquid storage pool, a film, a flow regulating cavity and a fluid outlet are arranged in the valve body, the film is provided with a plurality of overflow holes, and the inner surface of the flow regulating cavity is a smooth curved surface which is concave downwards; the inlet liquid storage tank and the flow regulating cavity are separated by a film and are communicated with the flow regulating cavity through overflow holes, and the bottom of the flow regulating cavity is communicated with the fluid outlet.

All the structures of the micro valve are micron-sized, the threshold pressure required for implementing constant flow regulation is not higher than 6kPa, and the flow range which can be output based on the micro valve structure optimization is 1 nL/min-10 mL/min.

Preferably, the thin film is a high-elasticity deformable film and can gradually adhere to the inner surface of the flow regulating cavity under the action of fluid pressure so as to achieve the purpose of flow limitation.

Preferably, the positions of the overflow holes are distributed on the outer side of the film, and when the film is attached to the inner surface of the flow regulating cavity, the positions of the overflow holes do not intersect with the positions of the fluid outlets.

Preferably, the material of the film is one of elastic materials such as polydimethylsiloxane, silica gel, polyurethane rubber polymer, shape memory alloy and the like.

Preferably, the inner surface of the flow regulating cavity can be one of smooth curved surfaces such as a spherical surface, an ellipsoid, an arc surface and the like.

Preferably, the diameter of the fluid outlet is much smaller than the diameter of the flow regulating cavity.

The process of using the micro valve comprises the following steps:

fluid flows into the valve body from the inlet liquid storage pool, sequentially passes through the overflow hole and the flow regulating cavity and flows out from the fluid outlet; the fluid in the cavity of the inlet liquid storage pool is acted by the fluid pressure source outside the valve body, so that the fluid in the cavity applies pressure to the upper surface of the film, the film is forced to generate downward elastic deformation and extrude the fluid in the flow regulating cavity, the flow resistance of the flow regulating cavity is changed, and the real-time regulation of the flow of the fluid outlet is realized; when the fluid pressure in the inlet liquid storage pool exceeds a certain threshold value, the film is infinitely attached to the inner surface of the flow regulating cavity, the change of the flow resistance of the flow regulating cavity can compensate the change of the fluid pressure in real time, and finally the micro valve realizes constant flow regulation.

The flow, the fluid pressure and the flow resistance have the following mathematical relations:

wherein Q is the flow of the fluid outlet, P is the fluid pressure of the inlet, R is the flow resistance of the flow regulating cavity, Δ P is the increment of the fluid pressure, and Δ R is the increment of the flow resistance. From the above mathematical relationship, the flow rate Q is directly related to the ratio of the fluid pressure P to the flow resistance R. Due to the existence of the membrane in the micro valve, the fluid pressure is increased, and the flow resistance of the flow regulating cavity is also increased. When the inlet pressure P exceeds a certain threshold value, the increment of the flow resistance delta R can completely compensate the increment of the fluid pressure delta P, namely the ratio of the fluid pressure P + delta P to the flow resistance R + delta R is always kept unchanged, and finally the micro valve outputs constant flow.

Has the advantages that: the utility model provides a low threshold value constant flow microvalve and flow regulation and control method compares prior art, has following beneficial effect:

the utility model provides a low threshold value constant flow microvalve is equipped with entry cistern, film, flow regulating chamber and fluid outlet, is equipped with the overflow hole on the film, and the internal surface in flow regulating chamber is smooth curved surface. The film can generate elastic deformation under the action of fluid pressure to extrude the fluid in the flow regulating cavity and change the flow resistance of the flow regulating cavity. When the deformed film is infinitely close to the inner surface of the flow regulating cavity, the flow resistance change of the flow regulating cavity can compensate the fluid pressure change of the inlet liquid storage pool, so that the automatic and accurate regulation and control of the micro-fluid flow are realized. Compared with the traditional micro valve, the cross section of the flow regulating cavity of the traditional micro valve is rectangular, and a dead zone exists between the thin film and the wall surface of the flow channel when the thin film is deformed under pressure, so that the threshold pressure for implementing constant flow regulation of the micro valve is higher (more than or equal to 25 kPa). The utility model provides a flow regulating intracavity surface of micro-valve is the cambered surface, can infinitely laminate flow regulating intracavity surface when the film warp to the influence in blind spot has been eliminated, makes the threshold pressure greatly reduced (less than or equal to 6kPa) of micro-valve. The micro valve has extremely low threshold pressure, so that the micro valve can be integrated with most micro-fluidic chips, and the application field of the micro valve is greatly expanded. The device has wide application value in the fields of medicine injection, integrated microchip laboratories, portable instant detection instruments and the like in the aspect of the requirement of providing constant flow supply.

Drawings

FIG. 1 is a schematic cross-sectional view of a low threshold constant flow microvalve;

FIG. 2 is a top view of a low threshold constant flow microvalve;

FIG. 3 is a schematic diagram of the operation of a low threshold constant flow microvalve to implement flow regulation;

FIG. 4 is a schematic diagram of a software simulation of a low-threshold constant-flow microvalve for flow regulation;

fig. 5 is a graph of experimental data from flow testing of a low threshold constant flow microvalve.

Wherein, 1 is a valve body, 2 is an inlet liquid storage pool, 3 is a film, 4 is an overflow hole, 5 is a flow regulating cavity, 51 is the inner surface of the flow regulating cavity, and 6 is a fluid outlet.

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are presented herein only to illustrate and explain the present invention, and not to limit the present invention.

A low-threshold constant-flow micro valve is shown in figures 1-3 and comprises a valve body 1, an inlet liquid storage pool 2, a film 3, an overflow hole 4, a flow regulating cavity 5 and a fluid outlet 6;

an inlet liquid storage tank 2, a film 3, a flow regulating cavity 5 and a fluid outlet 6 are arranged in the valve body 1, the film 3 is provided with two overflow holes 4 which are symmetrically arranged, and the inner surface 51 of the flow regulating cavity 5 is a smooth ellipsoid; the inlet liquid storage tank 2 is separated from the flow regulating cavity 5 by a film 3 and is communicated with the flow regulating cavity 5 through an overflow hole 4, and the bottom of the flow regulating cavity 5 is communicated with a fluid outlet 6; the thin film 3 is a high-elasticity deformable film made of polydimethylsiloxane, and can gradually adhere to the inner surface of the flow regulating cavity under the action of fluid pressure so as to achieve the purpose of flow limitation.

In this embodiment the inlet reservoir 2 has a diameter of 1500 μm and a depth of 1000 μm, the membrane 3 has a thickness of 50 μm, the two overflow apertures 4 have a diameter of 200 μm and a centre-to-centre distance of 1000 μm, the inner surface 51 of the flow-regulating chamber 5 has a diameter of 1500 μm and a height of 150 μm, the fluid outlet 6 has a diameter of 600 μm, and the valve body 1 has an outer diameter and a height of 5 mm. In order to theoretically study the flow control characteristics of the micro valve, finite element simulation software is adopted to carry out fluid-solid coupling modeling on the micro valve, the process of carrying out flow control on the micro valve is calculated, and the simulation result is shown in fig. 4. As shown, fluid flows from the inlet reservoir 2 through the overflow aperture 4 and the surge chamber 5 and out the fluid outlet 6, and fluid within the chamber of the inlet reservoir 2 is subjected to a fluid pressure source, causing the fluid within the chamber to press against the upper surface of the membrane 3, forcing the membrane 3 to resiliently deform downwardly and compress the fluid within the surge chamber 5. At this time, the volume of the flow regulating cavity 5 is reduced to increase the flow resistance, and the high flow resistance area is mainly concentrated on the edges of the overflow holes 3 at the two sides, the middle area of the film 3 and the flow regulating cavity 5 and the fluid outlet 6.

In order to further verify the constant-flow regulation and control capability of the micro valve, the micro valve sample piece with the size parameters is manufactured, and a flow test experiment is carried out. In the experiment, the inlet liquid pressure of the setting micro valve was gradually increased from 1kPa to 15kPa in sequence, and the flow rate of the micro valve was tested at the corresponding liquid pressure, and the pressure-flow rate curve was recorded as shown in FIG. 5. As can be seen from the flow curve, the outlet flow of the microvalve initially increases gradually as the inlet fluid pressure increases. When the inlet liquid pressure exceeds the threshold pressure by 6kPa, the microvalve flow rate tends to substantially stabilize. The average flow rate of the liquid pressure between 6kPa and 12kPa is calculated, and the flow rate is always kept at 4.03 +/-0.17 mL/min, and the fluctuation deviation of the flow rate is only 4.22%, and the micro valve shows good constant flow effect. When the liquid pressure exceeds 12kPa, the microvalve flow begins to slowly increase, gradually deviating from the mean flow value for the steady flow phase. In order to further verify the flow regulation and control characteristics of the micro valve, a film in the micro valve is removed, a straight-through flow channel device is manufactured, the flow data of the device is tested, and the flow data is compared with the flow data of the micro valve. As can be seen from the flow data of the flow-through device in the figure, the flow of the flow-through device increases almost always linearly with the increase in the inlet liquid pressure. Therefore, the micro valve in the embodiment has the remarkable constant flow self-regulation characteristic, and when the fluid pressure is between 6kPa and 12kPa, the micro valve can continuously output the almost constant flow.

The above description is only a preferred embodiment of the present invention, and it should be noted that: for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be considered as the protection scope of the present invention.

Claims

1. A low threshold constant flow microvalve characterized by: comprises a valve body (1), an inlet liquid storage pool (2), a film (3), an overflow hole (4), a flow regulating cavity (5) and a fluid outlet (6);

an inlet liquid storage pool (2), a film (3), a flow regulating cavity (5) and a fluid outlet (6) are arranged in the valve body (1), the film (3) is provided with a plurality of overflow holes (4), and the inner surface (51) of the flow regulating cavity (5) is a smooth curved surface which is concave downwards; the inlet liquid storage pool (2) is separated from the flow regulating cavity (5) by a film (3) and is communicated with the flow regulating cavity (5) through an overflow hole (4), and the bottom of the flow regulating cavity (5) is communicated with the fluid outlet (6).

2. A low threshold constant flow microvalve according to claim 1, wherein: the film (3) is a high-elasticity deformable film and can gradually attach to the inner surface (51) of the flow regulating cavity under the action of fluid pressure so as to achieve the purpose of flow limitation.

3. A low threshold constant flow microvalve according to claim 2, wherein: the positions of the overflow holes (4) are distributed on the outer side of the thin film (3), and when the thin film (3) is attached to the inner surface (51) of the flow regulating cavity (5), the positions of the overflow holes (4) are not crossed with the position of the fluid outlet (6).

4. A low threshold constant flow microvalve according to claim 2, wherein: the material of the film (3) is one of elastic materials such as polydimethylsiloxane, silica gel, polyurethane rubber polymer, shape memory alloy and the like.

5. A low threshold constant flow microvalve according to claim 1, wherein: the inner surface (51) of the flow regulating cavity (5) is one of a spherical surface, an ellipsoid and a cambered surface.

6. A low threshold constant flow microvalve according to claim 1, wherein: the diameter of the fluid outlet (6) is smaller than that of the flow regulating cavity (5).

7. A low threshold constant flow microvalve according to claim 1, wherein: the threshold pressure required by constant flow regulation of the low-threshold constant micro valve is not higher than 6kPa, and the outputtable flow range is 1 nL/min-10 mL/min based on micro valve structure optimization.