MICROFLUIDIC FLOW RATE CONTROL DEVICE AND METHOD

Abstract

A microfluidic flow rate control device for controlling a flow rate of a fluid flowing through a microfluidic conduit includes an inlet terminal for fluid input and an outlet terminal for fluid output, and a microfluidic conduit communicating the inlet terminal with the outlet terminal. The control device also includes; pumps for pumping the fluid through the conduit at a particular flow rate, valves for adjusting the flow rate of the fluid modifying their passageways, and a flow sensor for measuring the flow rate within the conduit and a controller for receiving the measured flow rate, comparing it with a predefined flow rate and instructing the pumps and/or the valves to modify their pumping powers and passageways of the valves, respectively, based on the result of the comparison. The microfluidic conduit, the pumps, the flow sensor and the valves may be arranged inside the protective housing.

Claims

1. A microfluidic flow rate control device for controlling a flow rate of a fluid flowing through a microfluidic conduit, characterized in that the control device comprises: an inlet terminal for fluid input and an outlet terminal for fluid output; the microfluidic conduit that fluidly connects the inlet terminal with the outlet terminal; at least one pump arranged in the microfluidic conduit for pumping the fluid through the microfluidic conduit at a flow rate; at least one valve arranged in the microfluidic conduit, the valves being configured to adjust the flow rate of the fluid by modifying their passageways; a flow sensor arranged in the microfluidic conduit, the flow sensor being configured to measure the flow rate within the microfluidic conduit; and a controller that is configured to receive the flow rate measured by the flow sensor, compare the measured flow rate with a predefined flow rate and instruct at least one of the at least one pump and the at least one valve to modify a pumping power of the pumps and the passageway of the valves, respectively, based on the result of the comparison.

2. The microfluidic flow rate control device according to claim 1, comprising a plurality of valves connected in series to each other along a portion of the microfluidic conduit.

3. The microfluidic flow rate control device according to claim 1, wherein the valves are pneumatic valves and the microfluidic flow rate control device comprises a respective pneumatic pump fluidly connected to each one of the pneumatic valves, the pneumatic pumps being configured to modify the passageway of the corresponding pneumatic valves based on the result of the comparison.

4. The microfluidic flow rate control device according to claim 1, comprising a plurality of micropumps connected in series for pumping the fluid through the microfluidic conduit.

5. The microfluidic flow rate control device according to claim 1, wherein the at least one valve is arranged in the microfluidic conduit between the flow sensor and the outlet terminal.

6. The microfluidic flow rate control device according to claim 1, comprising a main body at least partially housing the microfluidic conduit and wherein the at least one pump, the flow sensor, the controller and the at least one valve are removably coupled to the main body.

7. The microfluidic flow rate control device according to claim 1, wherein the pumps are piezoelectric micropumps and the valves are piezoelectric valves.

8. The microfluidic flow rate control device according to claim 1, comprising a flow resistance device arranged in the microfluidic conduit that is configured to introduce a constant pressure drop in the fluid flow flowing through the microfluidic conduit.

9. The microfluidic flow rate control device according to claim 1, comprising a pressure sensor arranged in the microfluidic conduit, the pressure sensor being configured to measure a pressure of the fluid flowing through the microfluidic conduit.

10. The microfluidic flow rate control device according to claim 1, comprising a temperature sensor arranged in the microfluidic conduit, the temperature sensor being configured to measure a temperature of the fluid flowing through the microfluidic conduit.

11. The microfluidic flow rate control device according to claim 1, comprising a graphical user interface communicatively coupled to at least one sensor of the microfluidic flow rate control device such that the graphical user interface is configured to display at least one of a flow rate, a pressure and a temperature of the fluid flowing through the microfluidic conduit measured by the at least one sensor.

12. A closed fluid circuit comprising a microfluidic flow rate control device according to claim 1.

13. An open fluid circuit comprising a microfluidic flow rate control device according to claim 1.

14. A method for controlling a flow rate of a fluid flowing through a microfluidic conduit that makes use of the microfluidic flow rate control device according to claim 1, the method including the following steps: pumping, by the at least one pump, the fluid through the microfluidic conduit at a flow rate, measuring, by the fluid sensor, the flow rate of the fluid within the microfluidic conduit, comparing, by the controller, the measured flow rate with a predefined flow rate, and instructing, by the controller, at least one of the at least one pump and the at least one valve to modify a pumping power of the pumps and a passageway of the valves, respectively, based on the result of the comparison.

15. The method for controlling a flow rate of a fluid flowing through a microfluidic conduit according to claim 14, wherein instructing the at least one valve to modify its passageway based on the result of the comparison comprises instructing the corresponding pneumatic pumps to adjust the passageway of the pneumatic valves based on the result of the comparison.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] To complete the description and in order to provide for a better understanding of the disclosure, a set of drawings is provided. Said drawings form an integral part of the description and illustrate an embodiment of the disclosure, which should not be interpreted as restricting the scope of the disclosure, but just as an example of how the disclosure can be carried out.

[0048] The drawings comprise the following figures:

[0049] FIG. 1 shows an exploded front perspective view of a microfluidic flow rate control device, according to a particular embodiment of the disclosure.

[0050] FIG. 2 shows the microfluidic flow rate control device of FIG. 1 with the pump, compressor and flowmeter being removably coupled to the main body.

[0051] FIG. 3 shows a rear perspective view of the microfluidic flow rate control device of FIG. 1 showing the flowmeter and how it is fluidly connected to the main body.

[0052] FIG. 4 shows another rear perspective view of the microfluidic flow rate control device of FIG. 1 showing the compressor and how it is fluidly connected to the main body.

[0053] FIGS. 5A and 5B show a front view and a side view, respectively, of the microfluidic flow rate control device of FIG. 1 including part of the microfluidic conduit that is marked with dotted lines.

[0054] FIG. 6 shows a block diagram of the microfluidic flow rate control device including the electronic subsystem, according to a particular embodiment of the disclosure.

[0055] FIG. 7 shows a flow diagram of the method for controlling a flow rate of a fluid flowing through a microfluidic conduit, according to an embodiment of the disclosure.

[0056] FIG. 8 shows a block diagram of a particular implementation of how the controller may determine instructing the valves and/or the pumps to modify their respective outlet flows based on the results of the comparison.

DETAILED DESCRIPTION OF THE DRAWINGS

[0057] FIG. 1 shows an exploded front perspective view of a microfluidic flow rate control device 100, according to a particular embodiment of the disclosure. FIG. 2 shows the microfluidic flow rate control device 100 of FIG. 1 with the pump 104, compressor 106 and flowmeter 105 being removably coupled to its main body 101. It should be understood that the control device 100 of FIGS. 1 and 2 may include additional components and that some of the components described herein may be removed and/or modified without departing from a scope of the described control device 100. Additionally, implementation of the control device 100 is not limited to such embodiment.

[0058] The microfluidic flow rate control device 100 comprises the main body 101 that partially houses the microfluidic conduit and to which the rest of the components of the microfluidic flow rate control device 100 are removably coupled. The main body 101 has an inlet terminal 102 through which a fluid, e.g., water, enters to the microfluidic conduit and an outlet terminal 103 through which the fluid leaves the microfluidic conduit at the corresponding regulated flow rate.

[0059] The microfluidic flow rate control device 100 further comprises a fluid pump 104, partially housed in an recess 119 of the main body 101, to pump the fluid through the microfluidic conduit, a flowmeter 105 to measure the flow rate at that point of the microfluidic conduit, two valves (not shown in this figure) arranged in the microfluidic conduit and located at the outlet terminal 103 and a compressor 106 to actuate the valves. The pump 104 comprises a respective inlet port 107 fluidly connected to the inlet terminal 102 of the microfluidic flow rate control device 100 via an interconnection pipe 108, and an outlet port 109 that is fluidly connected to an intermediate inlet port 110 of the main body 101 via an interconnection pipe 111. The pump 104 further comprises an electrical connector 104a to which an electrical wire is communicatively coupled to receive the instructions from the controller to modify the pumping power delivered by the pump 104 to the fluid. In particular, the inlet port 107 of the pump 104 and the interconnection pipe 111 are fluidly connected to the inlet terminal 102 by interposition of the intermediate port 120 and a conduit (not show in this figure) located in the main body 101 that interconnects the inlet terminal 102 to the intermediate port 120.

[0060] The flowmeter 105 comprises an inlet port 112 and an outlet port 113 which are fluidly and removably coupled to the respective flowmeter outlet port 114 and flowmeter inlet port 115, respectively, of the main body 101 by interposition of respective interconnection pipes 116a-b. In turn, the air compressor 106 is removably and fluidly coupled to a compressor inlet port 117 of the main body 101 by interposition of another interconnection pipe 118. The compressor 106 has four ports, two of them for sucking air and another two for delivering the compressed air. Since in this embodiment only one port of the compressor 106 is to deliver compressed air for actuating the valves, one of the inlet ports and one of the outlet ports of the compressor 106 are interconnected by means of a compressor interconnection pipe 121.

[0061] In such embodiment, the microfluidic conduit is formed by the conduits (not shown in this figure) within the main body 101, the conduits (not shown in this figure) within the pump 104, the conduits (not shown in this figure) within the flowmeter 105 and the interconnection pipes 108,111,116a-b that removably and fluidly communicate the pump 104 and the flowmeter 105 with the main body 101. The interconnection pipe 118 through which compressed air flows from the compressor 106 to the valves is not part of the microfluidic conduit.

[0062] While the microfluidic flow rate control device 100 of FIGS. 1 and 2 depicts one single pump, in some other embodiments there may be more than one pump connected in series to each other. Besides, although the microfluidic flow rate control device 100 of FIGS. 1 and 2 has one single compressor to actuate the two valves that it integrates, there may be more than one compressor that may actuate each one of the valves. In some other solutions, the valves may be piezoelectric valves fed by an electrical connection instead of by compressed air from a compressor. While the microfluidic flow rate control device 100 of FIGS. 1 and 2 shows this particular design, geometry and shape, the microfluidic flow rate control device 100 may have different geometries, designs and shapes depending on the particular uses it may have or the particular systems in which it may be installed.

[0063] In some other implementations of the microfluidic flow rate control device 100 of FIGS. 1 and 2, the pump, the valve, the compressor and the flowmeter may be integral parts of the main body or may be non-removable fixed to the main body.

[0064] FIG. 3 shows a rear perspective view of the microfluidic flow rate control device 100 of FIG. 1 showing the flowmeter 105 and how it is fluidly connected to the main body 101. The flowmeter inlet port 112 and the flow meter outlet port 113 are cylindrical ports whose diameter is greater than the diameter of the interconnection pipes 116a-b, such that the interconnection pipes 116a-b are introduced into said ports 112,113 and fluidly coupled to the flowmeter 105. The flowmeter 105 further comprises a connector 122 to which an electric wire is communicatively coupled to send the values of the measured flow rates to the controller. The measures may be periodically gathered by the flowmeter 105 or may be gathered only when the controller instructs the flowmeter 105 to do so. For example, the flowmeter 105 may measure the flow rate of the fluid flowing inside it every 5 ms.

[0065] FIG. 3 also shows the passing holes 123 in the support of the main body 101 that are used to fix the microfluidic flow rate control device 100 to a surface or to a component of the equipment it may be mounted on.

[0066] FIG. 4 shows another rear perspective view of the microfluidic flow rate control device 100 of FIG. 1 showing the compressor 106 and how it is fluidly connected to the main body 101. The compressor 106 is attached to the main body 101 by means of screws (not shown in this figure). The compressor 106 comprises two air inlet ports 124a and 125b and two air outlet ports 125a y 124b. In such embodiment, the air inlet port 125b and the air outlet port 124b are interconnected by means of the compressor interconnection pipe 121 to keep port 124a as the only air inlet port and port 125a as the only air outlet port that delivers the compressed air to the valves located inside the main body 101. The compressor 106 also incorporates a connector 106a (shown in FIG. 1), located in correspondence with its lower portion, to which an electrical wire is communicatively coupled to receive the instructions from the controller to modify the passageways of the valves in the microfluidic conduit to which it is fluidly connected.

[0067] FIGS. 5A and 5B show a front view and a side view, respectively, of the microfluidic flow rate control device 100 of FIG. 1 including the microfluidic conduit 125 that is housed inside the main body 101 and that is marked with dotted lines. The portions of the microfluidic conduit that are housed inside the pump 104, the flowmeter 105 and the interconnection pipes 108, 111 and 116a-b are not shown in these figures.

[0068] The microfluidic conduit 125 comprises: the inlet terminal 102, a first portion 125a corresponding to a first inner duct of the main body 101 connecting the inlet terminal 102 with the first intermediate port 120, a second portion corresponding to the interconnection pipe 108 (not shown in this figure) that fluidly connects the first intermediate port 120 to the inlet port 107 of the pump 104 (not shown in this figure), a third portion corresponding to the inner ducts of the pump 104 (not shown in this figure), a fourth portion corresponding to the interconnection pipe 111 (not shown in this figure) that fluidly connects the outlet port 108 of the pump 104 (not shown in this figure) to a second intermediate port 110, a fifth portion 125b corresponding to a second inner duct of the main body 101 that fluidly connects the second intermediate port 110 to the inlet opening of the flow resistance device, in particular, a serpentine circuit 125c, a sixth portion 125d corresponding to a third inner duct of the main body 101 that fluidly connects the outlet opening of the serpentine circuit 125c to the flowmeter outlet port 114, the flowmeter outlet port 114, the flowmeter inlet port 115, the respective interconnection pipes 116a-b (not shown in this figure) fluidly connecting the flowmeter outlet port 114 and the flowmeter inlet port 115 to the flowmeter 105 (not shown in this figure), the inner ducts of the flowmeter 105 (not shown in this figure), a seventh portion 125e corresponding to a fourth inner duct of the main body 101 that fluidly connects the flowmeter inlet port 115 to two valves 126, the inner ducts of the valves 126, a eighth portion 125f corresponding to a fifth inner duct of the main body 101 that fluidly connects the valves 126 to the outlet terminal 103 and the outlet terminal 103. The compressor inlet port 117, the interconnection pipe 118 (not shown in this figure) and the duct 127 fluidly connecting the compressor inlet port 117 to the valves 126 are not part of the microfluidic conduit 125. FIGS. 5A and 5B also shows the support elements 128 on which the compressor 106 is screwed to the main body 101.

[0069] While FIGS. 1 to 5 depict a microfluidic flow rate control device 100 having this particular disposition of the microfluidic conduit 125, valves 126, pump 104, flow resistance device 125c, flowmeter 105 and compressor 106 in the main body 101, other implementations of the microfluidic flow rate control device 100 may have a different design with different dispositions of the elements forming the microfluidic flow rate control device 100.

[0070] FIG. 6 shows a block diagram of the microfluidic flow rate control device 200 including its hydraulic subsystem 201 and its electronic subsystem 202, according to a particular embodiment of the disclosure. It should be understood that the control device 200 of FIG. 6 may include additional components and that some of the components described herein may be removed and/or modified without departing from a scope of the described control device 200. Additionally, implementation of the control device 200 is not limited to such embodiment.

[0071] The hydraulic subsystem 201 comprises all the components of the microfluidic flow rate control device 200 that mechanically impulse, monitor and regulate the flow of fluid that travels through the microfluidic flow rate control device 200. These components are those shown and described in FIGS. 1 to 5. For simplicity reasons only the pump 203, the valve 204 that is arranged in the microfluidic conduit 206 at the outlet of the pump 203 and the flowmeter 205 located at the outlet of the valve 204 are shown. Said hydraulic subsystem 201 and the electronic subsystem 202 are housed within a protective housing 207 that may be made of plastic or metallic material, among other materials, with enough structural rigidity to house and protect all the components of the microfluidic flow rate control device 200.

[0072] The electronic subsystem 202 comprises a controller 208, that may be a programmable PLC with its corresponding electronic circuitry, a screen 209, a keypad 210 and a memory 211. The controller 208 may fetch, decode, and execute instructions stored on memory 211 to perform the functionalities of the microfluidic flow rate control device described herein. The memory 211 may be any electronic, magnetic, optical, or other physical storage apparatus to contain or store information such as executable instructions, data, and the like. For example, any memory described herein may be any of Random Access Memory (RAM), volatile memory, non-volatile memory, flash memory, a storage drive (e.g., a hard drive), a solid state drive, any type of storage disc (e.g., a compact disc, a DVD, etc.), and the like, or a combination thereof.

[0073] The screen 209 is communicatively coupled with the controller 208 and is configured to display, via a graphical user interface, the parameters measured by the flowmeter or other sensors the control device 200 may integrate. The screen 209 is further configured to display a configuration settings menu of the control device 200. The keypad 210 is also communicatively coupled to the controller 208 and allows a user to select the operating parameters, such as the predefined flow rate value for the fluid flowing through the microfluidic conduit, the initial pumping power of the pumps, and the passageway of the valves, among others, of the microfluidic flow rate control device 200.

[0074] FIG. 7 shows a flow diagram of the method 300 for controlling a flow rate of a fluid flowing through a microfluidic conduit, according to an embodiment of the disclosure. Although the method 300 of FIG. 7 makes reference to the microfluidic flow rate control device 100 of FIGS. 1 to 5, it may refer to other control devices, such as the control device 200 of FIG. 6, according to the set of claims.

[0075] At step 301 of the method 300, the pump 104 of the microfluidic flow rate control device 100 pumps the fluid, e.g., water, entering via the inlet terminal 102 through the microfluidic conduit 125 at a particular flow rate. For example, this particular flow rate may range between 2000 and 500 microlitres per minute.

[0076] At step 302 of the method 300, the flowmeter 105 measures the flow rate of the fluid within the microfluidic conduit 125.

[0077] At step 303 of the method 300, the controller receives the flow rate measure by the flowmeter 105 and compares it with a predefined flow rate. From said comparison, the controller may determine whether there is a difference between both flow rates that should be corrected.

[0078] At step 304 of the method 300, the controller instructs at least one of the at least one pump 104 and the at least one valve 126 to modify their pumping powers and passageways, respectively, based on the result of the comparison, to minimize the difference between the measured flow rate and the predefined flow rate.

[0079] Instructing the at least one valve 126 to modify its passageway based on the result of the comparison comprises instructing the corresponding pneumatic pumps or compressors 106 to adjust the passageways of the pneumatic valves 126 based on the result of the comparison.

[0080] Preferably, the controller will instruct both, the valves 126 and the pumps 104 to adjust their passageways and pumping powers to adjust the fluid rate of the fluid flowing through the microfluidic conduit so that the predefined flow rate at the outlet terminal 103 of the microfluidic flow rate control device 100 is reached in the shortest period of time.

[0081] FIG. 8 shows a block diagram 400 of a particular implementation of how the controller may determine instructing the valves and/or the pumps to modify their passageways and pumping powers, respectively, based on the results of the comparison. The controller may incorporate fuzzy logic to make decisions on whether and to what extent valves and/or pumps will adjust their output flows.

[0082] As used herein, fuzzy logic has been described as many-valued logic as opposed to binary logic. Binary logic systems return a single truth value, or an answer that either matches the variable or does not. Rules including numerical values, for example, tend to be binary. Fuzzy logic, however, permits multiple matches to the logic and permits more contextually useful information. For example, it can indicate whether a certain operating parameter is high, low, or acceptablethat is, fuzzy logic can yield an answer that is actually a degree of truth rather than a crisp indication of truth. The fuzzy logic unit 401 of the present disclosure includes input variables, output variables, membership functions defined over the variables' ranges, and fuzzy rules or propositions relating inputs to outputs through the membership functions. The aggregation of all rules is the basis for the fuzzy logic inference process. The rules are applied to the input variables using an inference engine in light of the membership function and results in the output variable.

[0083] To do so, the fuzzy logic unit 401 receives the measures from the different sensors 402 the system 403 (the system refers to a global representation of the whole system, including the electrical, electronic and hydraulic elements of the control device) may integrate and together with the flow setpoints known from the functioning of the system 403, execute the pump and valve control actions to instructs the pump regulator drivers 404 and/or the valve regulator drivers 405 whether they should act on the respective pumps and/or valves of the system 403 and to what extent. In other words, the fuzzy logic unit 401 determines how much the pump regulator driver 404 and the valve regulator driver 405 are going to adjust their respective actions in order to minimize the difference between the measured flow rate and the predefined flow rate in the shortest lapse of time. Then, the pump regulator driver 404 and the valve regulator driver 405 will be varying their calculations for the pumping powers and/or passageways values for the pumps and valves, respectively, with the parameters the fuzzy logic has determined them to do until reaching the predefined flow rate at the microfluidic conduit. This fuzzy logic may be also applied to other parameters of the fluid such as the temperature, density, pressure that may be received from the sensors 402.

[0084] Therefore, the controller, by means of fuzzy logic, will instruct the pumps to continuously modify or adjust the pumping power they are applying and the valves to simultaneously and continuously modify or adjust their passageways so the difference between the predefined flow rate and the measured flow rate at the flow meter is minimized in the shortest lapse of time.

[0085] In this text, the term comprises and its derivations (such as comprising, etc.) should not be understood in an excluding sense, that is, these terms should not be interpreted as excluding the possibility that what is described and defined may include further elements, steps, etc. The term another, as used herein, is defined as at least a second or more. The term coupled, as used herein, is defined as connected, whether directly without any intervening elements or indirectly with at least one intervening elements, unless otherwise indicated. Two elements can be coupled mechanically, electrically, or communicatively linked through a communication channel, pathway, network, or system.

[0086] The disclosure is obviously not limited to the specific embodiments described herein, but also encompasses any variations that may be considered by any person skilled in the art (for example, as regards the choice of materials, dimensions, components, configuration, etc.), within the general scope of the disclosure as defined in the claims.