CN113266702A - Apparatus and method for controlling fluid - Google Patents

Abstract

The invention provides a device for controlling a fluid, comprising a fluid channel and at least one first piston means and at least one second piston means. The invention also provides a method for controlling the flow of fluid in a miniature and micro-fluidic device, wherein the miniature and micro-fluidic device is provided with the fluid control device. The device and the method provided by the invention can accurately and simply control the flow or storage of the fluid and the flow direction/flow rate in a micro or small flow channel system.

Description

Apparatus and method for controlling fluid

The present application claims priority from the following chinese patent applications: the invention entitled "apparatus and method for controlling fluid" filed on 14.2.2020, application No. 202010092879.2, is hereby incorporated by reference in its entirety.

Technical Field

The invention relates to the field of biotechnology and equipment application, in particular to a device for controlling fluid in a micro or small flow channel system and application thereof.

Background

Micro or small flow channel systems are widely used in chemical, biological, medical and other fields. The control of the fluid of a micro or small channel system is the basis for realizing the application of microfluid, and has very important significance.

Two major problems in the field of fluid control for micro or mini channel systems today include power source and valve issues. The power source provides power for movement of the microfluid within a carrier (e.g., chip, conduit, etc.). The currently commonly used modes include injection, centrifugal, pneumatic, etc. The valve can then control the movement behavior of the microfluid within the carrier. Due to the small dimensions of microfluidics, it is difficult to construct valves inside their carriers with sufficient precision, in sufficient numbers and to facilitate switching. For laboratories that study microfluidics, syringe pumps are the most common power source. The fluid is sucked into an injector, the injector is connected with an inlet of a micro-fluid carrier (hereinafter referred to as carrier), and the injector is pushed by a high-precision injection pump so as to realize the sample injection of the micro-fluid into the carrier. However, such operation steps are many, the switching of fluid samples is difficult, and the automatic sample injection of microfluid is difficult to realize.

Accordingly, there remains a need in the art for more convenient, less costly and more efficient methods and apparatus for controlling the flow of micro or mini-channel systems.

Disclosure of Invention

The present invention provides a fluid control device, comprising:

a fluid channel;

the first piston mechanism and the second piston mechanism are respectively provided with a first cavity and a second cavity which are communicated with the fluid channel, a first piston is arranged in the first cavity, a second piston is arranged in the second cavity, the first piston does a first motion relative to the first cavity, and the second piston does a second motion relative to the second cavity. The first and second cavities are in fluid communication, e.g., may be in communication through the fluid passage. In one aspect of the invention, the fluid control device is configured such that the first and second movements cause the first and second pistons to effect the same volume change in the first and second chambers but with opposite effects. The opposite effect on the volume change caused in the chamber means that, for example, a first movement causes the volume of the first piston caused in the first chamber to become larger, and a second movement causes the volume of the second piston caused in the second chamber to become smaller.

In one aspect of the present invention, the first piston mechanism and the second piston mechanism in the fluid control device are provided such that the pistons thereof are movable to a position blocking the fluid passage. For example, the cavity of the piston mechanism is perpendicular to the fluid passage, and the piston can move to the bottom of the fluid passage to block the fluid passage.

In one aspect of the present invention, the fluid control device may be configured such that one or both of the first piston mechanism and the second piston mechanism has a valve therebetween and the fluid passage. Fluid communication of the first piston means or the second piston means with the fluid passage is controlled by the valve. The valve may block or partially block fluid communication between the first or second piston means and the fluid passage.

In yet another aspect of the invention, the valve is a piston valve mechanism having a valve chamber in communication with the fluid passage and a valve piston within the valve chamber, movement of the valve piston within the valve chamber controlling fluid communication between the fluid passage and the first piston mechanism or the second piston mechanism controlled by the piston valve mechanism. For example, the piston valve mechanism is arranged such that the valve chamber is perpendicular to the fluid passage and the valve piston is movable to the bottom of the fluid passage to block the fluid passage.

In yet another aspect of the present invention, the piston valve mechanism is in fluid communication with the fluid passage and the first or second piston mechanism it controls through the valve flow passage. In one aspect of the invention, the valve flow passage is part of the fluid channel. The valve piston can move downwards to the bottom of the valve flow passage, namely the fluid passage, so that the flow passage is closed. In another aspect of the invention, the opening in the valve chamber of one or both of the valve flow passage communicating with the fluid passage or with the first piston means or the second piston means is located in the wall of the valve chamber, i.e. the opening is located higher than the fluid passage; the valve piston is movable (downwards) to a position blocking the opening, effecting closure of the flow passage.

In one aspect of the present invention, in the fluid control device, the piston mechanism or the piston valve mechanism has a piston that is controlled by a mechanical transmission or a pneumatic transmission.

In one aspect of the present invention, the fluid control device wherein the cross-section of the fluid channel has a width of about 0.1mm to about 5mm, preferably about 0.2mm to about 2 mm.

In one aspect of the present invention, the cross-section (e.g., circular) of the piston in the piston mechanism or piston valve mechanism has a diameter of about 1mm to 30mm, preferably 5 to 20 mm.

In one aspect of the present invention, in the fluid control device, the fluid passage includes a main flow passage and a branch flow passage. The at least one first piston mechanism and the at least one second piston mechanism may independently communicate with the main flow passage through the branch flow passages, respectively, or directly communicate with the main flow passage.

In one aspect of the invention, the fluid control device (e.g. the fluid passage thereof and/or the cavity of the piston mechanism) is adapted to contain a liquid material, a gaseous material, an emulsion material, a slurry material, a fluid material in which a solid material is dissolved, and a fluid material in which solid particles are suspended.

In another aspect of the present invention, there is provided a method for controlling the flow of fluid in a miniature and micro fluidic device having the aforementioned fluid control apparatus therein, the fluid control apparatus comprising:

a fluid channel;

the fluid control device is arranged to enable the first movement and the second movement to enable volume changes caused by the first piston and the second piston in the first cavity and the second cavity to be the same but opposite in action effect,

the method comprises the steps of: the at least one first piston mechanism and the at least one second piston mechanism work simultaneously, the first piston and the second piston are controlled to move simultaneously through a mechanical transmission or a pneumatic transmission mode, the volume change caused in the first cavity or the second cavity is the same, but the action effect is opposite, so that the fluid flows between the first cavity and the second cavity, and the flowing direction and/or the flowing quantity of the fluid are controlled through the moving speed and the moving distance of the pistons.

In another aspect of the invention, there is provided a microfluidic device comprising the aforementioned fluid control apparatus. The microfluidic device has a flow channel with a cross-sectional width of about 0.05-0.5 mm. In yet another aspect of the invention, the microfluidic device of the invention may be used for infection source identification, genetic disease, cancer detection, or genetic variation detection.

In another aspect of the invention, a kit is provided having a housing, a sample inlet, and the aforementioned fluid control device. In yet another aspect of the invention, the kit has a flow channel with a cross-sectional width of about 0.05-0.5 mm. In yet another aspect of the invention, the kit of the invention can be used for infection source identification, genetic disease, cancer detection or gene variation detection. In one aspect of the invention, the kit can be used to detect a biologically active substance, such as a nucleic acid or protein, in a sample. The kit has a holding space for holding a sample or various reaction reagents or performing various reactions, and the sample or various reaction reagents can flow in a fluid form between the respective holding spaces. The reaction includes the lysis of tissue or cells in a sample, the enrichment or extraction of a nucleic acid or protein sample, the amplification reaction of nucleic acids, the detection of nucleic acids or their amplification products or signals carried by them, and the like.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural diagram and a schematic work flow diagram of an exemplary fluid control device provided by the present invention. Fig. 1(a) - (f) show a schematic structural diagram and a work flow of a fluid control device provided by the present invention.

Fig. 2 is a schematic structural diagram and a schematic operational diagram of another exemplary fluid control device provided by the present disclosure. Fig. 2(a) - (i) show a schematic structural diagram and a work flow of the fluid control device provided by the invention.

Fig. 3 is a schematic diagram illustrating a mixing operation of liquids in a microchannel by the fluid control device according to the present invention. FIGS. 3(a) - (b) show the flow of the mixing operation of the fluid in the micro flow channel by the fluid control device of the present invention.

Fig. 4 is a schematic three-dimensional structure of an exemplary fluid control device of the present invention having a fluid storage and output unit. Fig. 4(a) shows an exemplary fluid control device of the present invention having a fluid storage and output unit. Fig. 4(b) shows another exemplary fluid control device of the present invention having a fluid storage and output unit.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of the present invention.

Example 1

Fig. 1 is a schematic structural diagram and a schematic operational diagram of an exemplary fluid control device provided by the present invention. As shown in fig. 1(a), the fluid control device provided by the present invention has a fluid channel 2, and the material of the wall (including the channel side wall and bottom 1) of the fluid channel 2 includes, but is not limited to, silica, silicon, quartz, glass or polymeric material (e.g., PDMS, plastic, etc.). The fluid control device provided by the invention is suitable for small-sized and micro-sized fluid equipment, is used for containing and transferring fluid materials such as liquid, and has a flow channel with the size of millimeter and micron, for example, about 0.05-5 mm. When the fluid control device is used in a microfluidic system, the flow channel dimensions are on the order of microns, for example the cross-sectional width of the flow channel is about 0.05-0.5 mm. In one aspect of the invention, the cross-section of the flow channel has a width of about 0.05 to 0.5mm, preferably about 0.05 to 0.2 mm. When the fluid control device is used in a small fluidic system such as a cartridge or the like, the flow channel dimensions are on the order of millimeters, e.g., the cross-sectional width of the flow channel is about 0.1-5 mm. The cross-section of the flow channel of the fluid channel may be various shapes including oval, rectangular, square, circular, etc. In one aspect of the invention, the cross-section of the flow channel has a width of about 0.1 to 5mm, preferably about 0.2 to 2 mm.

The present invention provides fluid control devices that employ two or more piston mechanisms to control the flow (static or moving), and the direction and/or amount of flow, of a fluid. In the exemplary fluid control device of the present invention of fig. 1, a piston mechanism 3 and a piston mechanism 4 are provided, which respectively have a chamber 31 and a chamber 41 communicating with the flow passage 2, the chamber 31 having a piston 32 therein, and the chamber 41 having a piston 42 therein. The device for controlling fluid provided by the invention can comprise two or more piston mechanisms. For example, in the device for controlling fluid provided by the exemplary invention of fig. 1, a piston mechanism 5 is further included, which has a chamber 51 communicating with the fluid passage 2 and a piston 52 therein. The piston means 5 may form the double piston means with the piston means 3 or the piston means 4.

In the present invention, the walls forming the chamber of the piston means are generally of the same material as the walls of the fluid passage. The piston of the piston mechanism can be made of materials such as rubber and polymers, has certain deformation capacity, can be tightly attached to the wall of the cavity of the piston mechanism to form a closed space through which liquid cannot pass, and meanwhile keeps good mobility of the piston in the cavity. The piston has a shape and size that cooperate with the cavity to limit the freedom of movement of the piston. In one aspect of the invention, the piston is circular and has a diameter of about 1mm to 30mm, preferably 5 to 20 mm.

In the exemplary present invention of FIG. 1, a fluid control device is provided in which the movement of the piston is controlled by a mechanical transmission. For example, the piston 32 is fixedly connected to the connecting rod 33, and the position of the piston 32 in the cavity 31 can be controlled by pushing and pulling the connecting rod. In other embodiments of the invention, the movement of the piston may also be controlled by other means, such as pneumatic transmission or the like.

In the device for controlling fluid provided by the present invention in fig. 1, the piston 32, 42, 52 may push to the bottom of the fluid channel 2, blocking the fluid channel.

In one aspect of the invention, in operation of the fluid control device, the two piston mechanisms operate simultaneously, wherein the two pistons move simultaneously but in opposite directions, causing the same volume change in the respective chambers, but in opposite directions, i.e. the volume in the chamber in one of the piston mechanisms increases and the volume in the chamber in the other piston mechanism decreases. In one aspect of the invention, the two or more piston mechanisms have the same piston cross section, so that when the two piston mechanisms work simultaneously, the speeds of the respective pistons are controlled to be the same, namely, the volume changes caused by the pistons in the corresponding cavities are the same but the effects are opposite.

In the invention, when the fluid control device works, the fluid flow in the fluid channel can be controlled by controlling the movement of the piston in the cavity.

The fluid control device provided by the invention can realize the sample injection or storage of the fluid and control the flow direction/flow rate of the fluid by controlling the movement of the piston, and the working process is shown in figures 1(a) to 1 (f).

In fig. 1(a), all pistons (32, 42 and 52) in the device are pushed to the bottom of the flow channel 2, i.e. all are in a closed state, and there is no flow of liquid in the flow channel 2. Liquid 7 is added to the inlet flow channel 6. When it is desired to control the amount of liquid to be removed or stored, a specified amount of liquid 7 may be added (e.g. a metered amount of solution reagent as desired), or by controlling the movement of the piston (i.e. the volume of the chamber).

The piston 32 is pulled up, so that a negative pressure is created in the space of the chamber 31 below the piston. The liquid at the inlet will pass through the flow channel 21 into the negative pressure region of the chamber 31. As shown in fig. 1(b) and 1 (c).

The piston 32 is then pushed down, pulling the piston 42 up at the same speed, and the liquid will pass through the flow passage 22 into the negative pressure region of the chamber 41. As shown in fig. 1(d) and 1 (f).

Pistons 42 and 52 may then be similarly controlled by pushing piston 42 downward while pulling piston 52 upward at the same rate, causing fluid to move from chamber 41 through flow passage 23 to chamber 51. As shown in fig. 1 (f).

Wherein the cavity 31 or 41 or 51 can be used for storing and releasing the liquid flowing through. The chamber 31 or 41 or 51 may be connected to or part of other flow channels. For example, the chamber has passage openings connected to other flow passages, which can be closed and opened. Fluid entering the cavity may be stored within the cavity or flow through the channel to other flow passages.

The inventors have unexpectedly found that as fluid moves from chamber 31 to chamber 41, fluid only moves from chamber 31 to chamber 41 and is not pushed back into inlet flow passage 6, nor is gas drawn from the inlet into the negative pressure region of the chamber, because the negative pressure provided by the upward movement of piston 42 is complementary to the positive pressure created by the downward movement of piston 32. When the piston mechanism 3 sucks in liquid from the inlet, the liquid at the inlet does not need to be completely sucked into the chamber 31, but can be sucked in according to the required amount. When the sectional areas of the pistons 32 and 42 are the same, the moving speed and the moving distance of the control piston 42 are the same as those of the piston 32, and the moving direction is opposite, so that the solution in the chamber 31 can be sucked into the chamber 41 without more liquid being sucked from the inlet flow channel 6.

When the flow channel of the fluid control device provided by the invention is provided with a plurality of piston mechanisms, the flow of the fluid in any two piston mechanisms can be controlled by the movement of the pistons of the two piston mechanisms, so that the transfer of the fluid between different cavities is realized. For example, in the exemplary fluid management device of the present invention of fig. 1, the controllable piston 42 remains stationary in the chamber above the flow path, and fluid is transferred between chambers 31 and 51 by controlling the movement of pistons 32 and 52. When the chamber 31 or 51 is connected to other flow channels, the movement of the fluid in the flow channel connected to the chamber 31 or 51 can be realized.

Example 2

Fig. 2 is a schematic structural diagram and a schematic operational diagram of another exemplary fluid control device provided by the present disclosure.

In the exemplary fluid control device of the present invention of fig. 2, the piston mechanism 3 and the piston mechanism 4 are provided, respectively, with a cavity 31 and a cavity 41 communicating with the flow channel 2, the cavity 31 having a piston 32 therein, and the cavity 41 having a piston 42 therein.

In this embodiment, the piston means further comprises a valve between one or both of the piston means and the fluid passage. Fluid communication with the fluid passage is controlled by the valve control piston mechanism. For example, the valve may block or partially block fluid communication between the piston mechanism and the fluid passage.

In the apparatus for controlling fluid provided by the present invention as exemplified in fig. 2, the valve is a piston mechanism. As shown, upstream of the piston mechanism 3, a piston valve mechanism 8 is provided having a valve chamber 81 with a valve piston 82 therein. The valve chamber 81 communicates with the chamber 31 through the valve flow passage 211. The opening 84 of the flow channel 211 in the valve chamber 81 is located in the wall of the chamber, i.e. the opening is located higher than the fluid channel 2. The arrangement of the valve flow channel opening in the valve chamber on the wall of the valve chamber, i.e. the valve flow channel is not part of the fluid channel, but rather is higher than the fluid channel, makes the closing of the valve flow channel more effective. The valve piston 82 may push to the bottom of the fluid passage 2, blocking the fluid passage. Additionally, the thickness of the valve piston 82 is greater than the width of the opening 84; the valve piston 82 thereby blocks the opening 84 sufficiently to close the flow path between the valve chamber 81 and the chamber 31.

In the device for controlling a fluid according to the present invention as exemplified in fig. 2, a piston valve mechanism 9 having a valve chamber 91 with a valve piston 92 therein is provided downstream of the piston mechanism 4. The valve chamber 91 communicates with the outlet flow passage 10 via the valve flow passage 231. The opening 94 of the valve flow channel 231 in the valve cavity 91 is located on the wall of the cavity above the flow channel base. The valve piston 92 and the opening 94 are arranged such that when the valve piston 92 is depressed, the opening 94 is completely blocked, closing off the flow passage.

In the exemplary fluid-handling device of the present invention of fig. 2, the movement of the piston is controlled by a pneumatic transmission mechanism.

The work flow is shown in fig. 2(a) -2 (i).

In fig. 2(a), all the pistons (31, 41, 81 and 91) in the device are pushed to the bottom of the flow channel 2, i.e. all are in a closed state, and there is no flow of liquid in the flow channel 2. Liquid 7 is added to the inlet flow channel 6. When it is desired to control the amount of liquid added, a specified amount of liquid 7 may be added (e.g., a metered amount of solution reagent may be added as desired), or it may be controlled by controlling the movement of the plunger (i.e., the volume of the chamber).

The negative pressure is generated in the space above the piston 82 by the pneumatic device, causing the piston 82 to rise, thereby creating a negative pressure in the space of the chamber 81 below the piston. Liquid at the inlet will pass through the flow channel 21 into the negative pressure region of the chamber 81. As shown in fig. 2 (b).

Then, negative pressure is generated in the space of the cavity 31 above the piston 32 by the pneumatic device, so that the piston 32 moves upward, thereby forming negative pressure in the space of the cavity 31 below the piston. The liquid passes through the flow passage 211 into the negative pressure region of the chamber 31. As shown in fig. 2 (c).

A positive pressure is generated in the space above the piston 82 by the pneumatic device, so that the piston 82 descends to the bottom of the flow passage. The chamber 31 is closed off from the flow path between the inlet flow channel 6 and the chamber 81. As shown in fig. 2 (d).

Moving the piston 32 downwards and at the same time moving the piston 42 upwards at the same speed, the liquid will pass through the flow passage 22 into the negative pressure region of the chamber 41. As shown in fig. 2(e) and 2 (f). Because the piston valve mechanisms 8 and 9 are both in the closed state, when the piston 32 moves downward, the space above the piston 42 can be kept at normal pressure (i.e. communicated with the atmosphere), and the piston 42 is also pushed upward by the hydraulic pressure generated by the downward movement of the piston 32, so that the liquid is transferred from the cavity 31 to the cavity 41.

Then, a negative pressure may be generated in the space above the piston 92 by the pneumatic device, so that the piston 92 is lifted, thereby communicating the flow passage 23 and the flow passage 231. As shown in fig. 2 (g). Then, the piston 42 is lowered by generating positive pressure in the space above the piston 42 by the air pressure, and the liquid in the chamber 41 enters the chamber 91 through the flow passage 23 and further enters the downstream flow passage through the flow passage 231. As shown in fig. 2 (h).

Finally, the piston 92 may be moved downward and the liquid remaining in the chamber 91 may pass through the flow channel 231 into the downstream flow channel. As shown in fig. 2 (i).

By providing a valve upstream or downstream of the piston mechanism of the device of the present invention, it is possible to more effectively prevent the occurrence of a phenomenon such as a reverse flow of fluid. The valve is realized by a piston mechanism, so that the operation mode and the system of the equipment can be unified. The flow channel opening in the piston valve mechanism is arranged on the wall of the valve cavity body higher than the flow channel base, so that the phenomena of backflow and the like of fluid can be effectively prevented.

Example 3

Mixing of liquids in micro or small flow channel systems such as microfluidic devices or kits is very difficult. This is because the smaller the characteristic size of the liquid, the smaller the reynolds number, the more and more dominant the viscous force will be compared to the inertial force, and thus the mass transfer efficiency of the microfluid becomes extremely low.

The fluid control device provided by the invention is provided with two or more piston mechanisms, and can effectively mix liquid for the combined operation of any two or more piston mechanisms. Fig. 3 is a schematic view of a mixing operation of liquids in a micro flow channel using the fluid control device of the present invention as described in example 2.

As shown in fig. 3(a), different liquids or different fractions of the same liquid (liquid 71 and liquid 72) are present in the chamber 31 and the chamber 41 of the two communicating piston mechanisms 3 and 4, respectively.

As shown in fig. 3(b), mixing of the liquids 71 and 72 can be achieved by controlling the pistons 32 and 42 to move at the same speed and in different directions. It is worth mentioning that, because the piston valve mechanisms 8 and 9 are provided upstream and downstream, there is no liquid leakage from the flow passage 21 or 23 as long as the piston valve mechanisms 8 and 9 remain closed, thereby reducing the requirement for accuracy in controlling the movement of the pistons 32 and 42.

Thus, the chambers of two or more piston mechanisms in the fluid control device provided by the invention can be used as reaction chambers of micro or small flow channel systems such as microfluidic devices or kits, and liquid operations such as mixing and reaction can be carried out in the reaction chambers.

Example 4

In the application of micro or small flow channel systems such as microfluidic devices or kits, a certain fluid needs to be temporarily stopped (stored) in a certain area inside the system and then sent out to participate in a reaction when needed.

The fluid control device provided by the invention is provided with two or more piston mechanisms, and the combined operation of the piston mechanisms can control the staying and outputting of the fluid in the system to form a fluid storage and output unit.

FIG. 4 is a schematic three-dimensional view of an exemplary fluid control device having a fluid storage and output unit.

Fig. 4(a) shows a fluid control device having a housing 100 and a flow channel 200, wherein the flow channel 200 includes a main flow channel 201 and a branch flow channel 202. The fluid control device comprises three piston mechanisms 300, 400 and 500, wherein the piston mechanisms 300 and 500 are positioned on the main flow passage 201, and the piston mechanism 400 is positioned at the tail end of the branch flow passage 202. In this exemplary fluid control device, similarly to the method of controlling the movement of the piston to perform the injection or storage of the fluid in embodiment 1, the liquid can be introduced from the piston mechanism 300 through the main flow passage 201 and the branch flow passage 202 into the chamber 401 of the piston mechanism 400. For example, by simultaneously depressing the piston 302 of the piston mechanism 300 and pulling up the piston 402 of the piston mechanism 400, so that the liquid to be stored flows from the chamber 301 of the piston mechanism 300 through the main flow passage 201 and through the branch flow passage 202 into the cavity 401 of the piston mechanism 400, the volume of the stored liquid can be adjusted by the distance the piston 402 is pulled up as required. In one aspect of the present invention, the liquid to be stored is directly introduced from the input port through the main flow channel 201 and through the branch flow channel 202 into the cavity 401 of the piston mechanism 400 by pulling up the piston 402 of the piston mechanism 400, while the piston 302 of the piston mechanism 300 remains stationary and does not obstruct the flow communication of the main flow channel.

Thereafter, the primary flow passage 201 may still be used to transfer other fluids, keeping the piston 402 stationary. When the stored liquid is needed, the piston 402 is pushed downwards, so that the liquid stored in the piston can be pushed out through the branch flow passage 202, and the using amount of the liquid can be controlled by controlling the distance of the downward pushing of the piston 402. When there is liquid present in the piston mechanism 400, the pressure in the closed cavity of the piston mechanism 400 remains constant as long as the piston 402 remains stationary. At this time, the liquid remaining in the piston mechanism 400 does not leak out through the branch flow passage 202 regardless of whether or not the remaining liquid flows in the main flow passage 201.

Similarly, fluid may be moved or stopped between the chamber 401 of the piston mechanism 400 and the chamber 501 or flow channel of the piston mechanism 500 by operation of the pistons 402 and 502.

Fig. 4(b) shows an example fluid control device in which, in addition to the example fluid control device of fig. 4(a), a piston valve mechanism 600 is provided in the branch flow passage 202, i.e., between the piston mechanism 400 and the main flow passage 201. The piston valve mechanism 600 has a valve chamber 601 with a valve piston 602 therein. The valve piston 602 may push to the bottom of the bypass channel 202, blocking the fluid path. Similar to examples 2 and 3, the application of the piston valve mechanism reduces the control accuracy requirements on the piston of the piston mechanism during fluid transfer, and enhances the stability of the system. In the example fluid control device shown in fig. 4(b), the branch flow path 202 connected to the main flow path 201 is located on the wall of the valve chamber 601 at the opening thereof (i.e., a valve flow path communicating with the flow path is formed by the piston valve mechanism 600). In other embodiments of the present invention, the branch flow channel 202 connected to the main flow channel 201 and/or the branch flow channel 202 connected to the piston valve mechanism 600 is located on the wall of the valve chamber 601 at the opening thereof.

Therefore, the chambers of the two or more piston mechanisms in the fluid control device provided by the invention can be used as a fluid storage chamber of a micro or small flow channel system such as a microfluidic device or a kit, and used for controlling the stay and output of the fluid in the system, and a fluid storage and output unit is formed in the application of the micro or small flow channel system such as the microfluidic device or the kit.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims (10)

1. A fluid control device, comprising:

a fluid channel;

at least one first piston mechanism and at least one second piston mechanism, the first piston mechanism and the second piston mechanism respectively having a first cavity and a second cavity communicated with the fluid passage, the first cavity having a first piston therein, the second cavity having a second piston therein, the first piston making a first movement relative to the first cavity and the second piston making a second movement relative to the second cavity,

wherein the fluid control device is arranged such that the first and second movements cause the same volume change in the first and second chambers as the first and second pistons, but with opposite effects.

2. A fluid control device as claimed in claim 1 wherein the first and second piston means are arranged such that their pistons are movable to a position blocking the fluid passage, for example with their chambers perpendicular to the fluid passage, the pistons being movable to the bottom of the fluid passage to block the fluid passage.

3. The fluid control device according to claim 1, wherein one or both of the first and second piston mechanisms has a valve therebetween and the fluid passage.

4. The apparatus of claim 3, wherein the valve is a piston valve mechanism having a valve chamber in communication with the fluid passage and a valve piston within the valve chamber, the piston valve mechanism being in fluid communication with the fluid passage and the first or second piston mechanism it controls through the valve passage.

5. A fluid control device as claimed in claim 4 wherein one or both of the valve flow passages communicating with the fluid passage or with the first or second piston means is provided with an opening in the valve chamber in a wall of the valve chamber and the valve piston is movable to a position in which it blocks said opening to effect closure of the flow passage.

6. A fluid control device as claimed in any of claims 1 to 5 wherein the pistons in the piston means or piston valve means are each independently controlled by mechanical or pneumatic transmission.

7. The fluid control device according to any one of claims 1-6, wherein the cross-section of the fluid channel has a width of about 0.1mm-5mm, preferably about 0.2mm-2 mm.

8. A fluid control device according to any of claims 1-7, characterized in that the diameter of the cross-section of the piston in the piston means or piston valve means is about 1-30 mm, preferably 5-20 mm.

9. The fluid control device according to any one of claims 1-8, wherein the fluid passage comprises a main flow passage and a branch flow passage, and the at least one first piston means and the at least one second piston means are independently communicable with the main flow passage via the branch flow passages, respectively, or directly communicable with the main flow passage.

10. A method of controlling the flow of fluid in a miniature and micro fluidic device having a fluid control device according to any of claims 1-9 therein, the fluid control device comprising:

a fluid channel;

the fluid control device is arranged to enable the first movement and the second movement to enable volume changes caused by the first piston and the second piston in the first cavity and the second cavity to be the same but opposite in action effect,

the method comprises the steps of: the at least one first piston mechanism and the at least one second piston mechanism work simultaneously, the first piston and the second piston are controlled to move simultaneously through a mechanical transmission or a pneumatic transmission mode, the volume change caused in the first cavity or the second cavity is the same, but the action effect is opposite, so that the fluid flows between the first cavity and the second cavity, and the flowing direction and/or the flowing quantity of the fluid are controlled through the moving speed and the moving distance of the pistons.

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