JP4326465B2 - Fluid mixing device - Google Patents

Description

  The present invention relates to an apparatus that mixes a plurality of types of fluids, and more particularly to an apparatus that performs mixing using a fluid flow.

  When mixing multiple types of liquids while sending them in one flow path, a device such as a static mixer that uses a fixed arrangement of several wings, for example, flat plates twisted in the flow path, may be used. is there. The flowing liquid swirls and agitates the blade, and as a result, a plurality of types of liquids are mixed. There is also known an apparatus for rotating and mixing a blade disposed in a flow path. A mixing device using only diffusion as shown in FIG. 14 is also known. In this device, a large number of fine holes are formed in the wall surface 200 of the flow path, and the drug is mixed from these holes. By feeding the sample water in the direction of the arrow 202 and mixing the reagent (shown by the arrow 204) through the fine holes in the wall surface 200, the mixed liquid flows out in the direction of the arrow 206.

  Non-Patent Document 1 below describes an apparatus that performs mixing by alternately sending two types of liquids using two micropumps.

Ajay A. Deshmukh and two others, “CONTINOUS MICROMIXER WITH PULSATILE MICROPUMPS”, [online], University of California, Berkeley, October 31, 2003, Internet <URL: http://www.me.berkeley.edu/~liepmann/assets/deshmukh_HiltonHead.pdf>

  When mixing a small amount of liquid, the flow rate is low, the flow becomes laminar, and mixing between layers does not proceed. Even in the above-described apparatus in which a fixed blade is disposed in the flow path, a laminar flow is formed along the blade, and mixing due to local turbulence does not proceed. In addition, the fluid flowing through the gap between the blade and the flow path wall is not mixed and cannot be mixed efficiently. In a device that stirs by rotating blades, etc., the flow path for flowing a small amount of fluid is narrow, and it is difficult to place a rotating structure in the flow path. It becomes. In addition, in order to mix a liquid from a large number of micropores provided in the walls of the flow path, it is necessary to provide a flow path for flowing the reagent in a layer separate from the flow path of the sample water, and the structure is complicated due to the multilayer structure. Become. In addition, it is necessary to make a large wall surface for providing the fine holes, which increases the size of the apparatus. In addition, the portion provided with the fine holes is wider than the front and rear flow paths, and the flow may stay in a portion where the cross-sectional area of the flow path changes. Further, since the flow path is widened, there is a problem that a large amount of liquid remains in the apparatus when the apparatus is stopped, resulting in a lot of waste. In addition, these devices require a separate means for sending a liquid such as a pump, and there is a problem that the entire device cannot be miniaturized.

  In the mixing apparatus of Non-Patent Document 1, the two pumps are driven alternately to increase the contact area of the two liquids to be mixed, but after that, they are sent in a state where the layers are separated. Therefore, it is necessary to wait for mixing by diffusion, and it is necessary to sufficiently lengthen the flow path downstream from the junction.

  According to the present invention, when a plurality of liquids are mixed, it is advantageous even at a minute flow rate such that the flow becomes a laminar flow.

  The fluid mixing apparatus of the present invention includes a plurality of pumps for each type of a plurality of fluids to be mixed, and fluids are intermittently alternately or sequentially sent from these pumps. The fluid sent out from each pump flows through the branch flow path and joins the main flow path. Then, during a discharge stroke of a certain pump, a part of the fluid discharged from this pump flows into the branch flow path of at least one other pump and backflows. This backflow promotes fluid mixing.

  The above-described pump can be a reciprocating pump provided with a check valve in each flow path on the suction side and the discharge side. The check valve on the discharge side has a structure that allows a certain amount of back flow, so that a part of the fluid discharged from at least one pump other than the pump provided with a certain check valve It backflows into the branch flow path connected to the check valve to promote fluid mixing.

  The structure that allows the check valve to back flow can leave a slight gap even when the valve is closed. More specifically, when the valve body is seated on the valve seat, a slight gap may be formed between them.

  In addition, the check valve may be provided with a drive unit for opening and closing the check valve, and the check valve may be opened during at least a part of the discharge period of other pumps to allow backflow.

  A sub-chamber having a variable volume may be provided in the branch flow path to allow back flow. For example, part of the sub chamber is made of an elastic body, and the elastic body is deformed by the pressure of the fluid, so that the volume changes. Due to the discharge pressure of a pump other than the pump to which a certain subchamber is related, the elastic body of the subchamber is deformed, and a reverse flow of the volume due to this deformation is allowed. Further, a drive unit may be provided on the elastic body of the sub chamber to actively change the volume of the sub chamber.

  Moreover, the pump can be a positive displacement rotary pump capable of reverse operation. During a discharge stroke of a certain pump, at least one other pump is operated in reverse so that a part of the fluid discharged in the certain pump is drawn. Thereby, a backflow is generated and mixing of the fluid is promoted.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a fluid mixing apparatus 10 of the present embodiment. The fluid mixing apparatus 10 includes two micro diaphragm pumps 12A and 12B. These pumps 12A and 12B have the same configuration, and in the case where it is not necessary to distinguish between them, the following description will be made simply using reference numeral 12. In the following description, a subscript A is attached to a configuration belonging to or related to the diaphragm pump 12A, and a subscript B is attached to a configuration belonging to or related to the diaphragm pump 12B. These configurations are also omitted when it is not necessary to distinguish between A and B.

  The pump chambers 13A and 13B of the two diaphragm pumps 12A and 12B are respectively provided with suction side check valves 14A and 14B and discharge side check valves 16A and 16B. Suction side check valves 14A and 14B are connected to suction ports 18A and 18B, respectively. Further, the branch flow paths 20A and 20B extend from the discharge-side check valves 16A and 16B, and they merge at the junction 22. From the merging point 22, there is one main flow path 24 that reaches the discharge port 26. Further, the branch flow paths 20A and 20B are provided with flow meters 21A and 21B, respectively, and the provided flow rates are measured. These flow meters are preferably capable of measuring the flow rate flowing in both the forward and reverse directions. By measuring the flow rate in the reverse direction, the flow rate of each fluid can be grasped even if a reverse flow occurs, so that the accuracy of the fluid mixing ratio can be improved.

  FIG. 2 is a cross-sectional view showing a schematic configuration of the diaphragm pump 12. FIG. 2A is a perspective view showing the shape of the upper surface of the glass substrate 28 to help understanding the cross-sectional view of FIG. The pump chamber 13 is formed by covering the concave portion 30 provided in the glass substrate 28 with a silicon processing plate 32 processed into a predetermined shape. A portion of the processing plate 32 that faces the pump chamber 13 is thinly processed, and this portion functions as a diaphragm 34. A piezoelectric element 36 is joined to the diaphragm 34. When a voltage is applied to the piezoelectric element 36, the piezoelectric element 36 is deformed, and the diaphragm 34 is also deformed accordingly. Due to the deformation of the diaphragm 34, the volume of the pump chamber 13 is expanded or reduced. By controlling the waveform of the voltage applied to the piezoelectric element 36, the deformation amount of the power generating element 36, that is, the discharge flow rate of the pump can be controlled.

  When a biological fluid such as blood is used as a handling fluid, it is necessary to configure the pump with a biocompatible material. Glass has good biocompatibility, and single crystal silicon also has relatively good biocompatibility. When silicon is oxidized to form an oxide film, silicon dioxide is obtained, and biocompatibility is improved as compared with single crystal silicon. Other biocompatible materials include PC (polycarbonate), PMMA (polymetamethyl acrylate), PVC (vinyl chloride), ultra-high molecular weight PE (polyethylene), metals such as titanium, and ceramics such as aluminum oxide. There are materials and jewelry such as diamond, sapphire and ruby. Diamond, sapphire, and the like are used as materials for micromachining technology, and can also be used as part of this embodiment. Further, titanium or the like can form a flow path by metal etching.

  The substrate 28 is formed with a groove-like suction flow path 38 through which a fluid flowing toward the pump chamber 13 flows. The portion protruding into the suction flow path 38 becomes the valve seat 40 of the suction-side check valve 14, and a thinly processed plate-like portion having a hole in the center of the processing plate 32 provided corresponding thereto is the valve. It becomes the body 42. The valve body 42 bends upward in the figure with respect to the flow of fluid toward the pump chamber 13, and this flow is allowed. However, for the reverse flow, the flow causes the valve body 42 to move to the valve seat 40. This acts as a push and prevents this. The discharge side check valve 16 also has substantially the same configuration as the suction side, and is provided corresponding to the valve seat 44 provided so as to protrude from the flow path carved in the substrate 28. A plate-like valve body 46 having a hole in the center is provided. Further, in the discharge side check valve, the valve seat 44 is formed with a groove 48 that forms a gap for allowing a slight flow even when the valve body 46 is seated. The discharge side check valve 16 allows the flow toward the pump chamber 13 slightly by the groove 48. Upper portions of the processed plate 36 where the suction side check valve 14 and the discharge side check valve 16 are formed are covered with glass covers 50 and 52. The reverse flow rate is a range of volume change of the pump chamber 13 and can be controlled by the size, thickness, elastic modulus of the diaphragm, and the voltage applied to the piezoelectric element. The reverse flow rate can be, for example, 10 to 100%, preferably 30 to 100% of the discharge amount.

FIG. 3 is a timing chart showing the operation of the fluid mixing apparatus 10. (A)-(d) is a chart relevant to one pump, for example, diaphragm pump 12A, (e)-(h) is a chart relevant to the other diaphragm pump 12B. (A) and (e) show the flow rate of the fluid sucked from the suction port 18 by the pump and the flow rate sent to the discharge port 26, the positive side (upper side in the figure) shows the discharge flow rate, and the negative side sucks the flow rate. Indicates the flow rate.
(B) and (f) show the displacement of the diaphragm 34, and the pump chamber 13 contracts on the positive side and expands on the negative side. (C), (g) shows the opening / closing operation of the suction side check valve 14, and (d), (h) shows the opening / closing operation of the discharge side check valve 16. Further, (i) shows the discharge amount and the combined discharge amount of each of the two diaphragm pumps 12A and 12B. In (i), the graph indicated by the alternate long and short dash line indicates the flow rate of the diaphragm pump 12B, and the graph indicated by the broken line indicates the flow rate of the diaphragm pump 12B. The operations of the two diaphragm pumps 12A and 12B are exactly the same with respect to other points except that the phases differ by 180 °. The total discharge amount of these two pumps 12A and 12B is indicated by a solid line. As described above, the fluid mixing apparatus 10 can mix two kinds of fluids at a ratio of 1: 1 and send out the mixed fluid at a constant discharge flow rate, that is, without pulsation. Changing the mixing ratio from 1: 1 while maintaining no pulsation can be achieved by changing the discharge periods of the two pumps.

  In the diaphragm pump 12, as shown in FIG. 2, a groove 48 that forms a gap is provided in the discharge-side check valve 16. For this reason, a backflow occurs and the flow rate decreases. 3 (a) and 3 (e) is a flow rate when there is no gap in the valve and no reverse flow occurs, and the actual flow rate is smaller than this as shown by the solid line. As shown in each chart of FIG. 3, during the discharge period of the diaphragm pump 12A, the discharge-side check valve 16B of the other diaphragm pump 12B is basically in a closed state. Therefore, the fluid remaining in the branch flow path 20B is pushed back into the pump chamber 13B. This reduces the efficiency and the flow rate.

  FIG. 4 schematically shows the flow in the vicinity of the confluence 22 when a backflow occurs. The fluid sent out through the branch channel 20A is divided into a main channel 24 and another branch channel 20B. At this time, since the flow path is bent at the junction, a vortex is generated and mixing is promoted. In this way, a part of the fluid discharged from the diaphragm pump flows back to the flow path from the other diaphragm pump and mixed, and then sent out, so that mixing proceeds at an early stage and the length of the main flow path is shortened. Is possible.

  Further, as shown in FIG. 4, the vortex is positively formed by the two branch channels 20 </ b> A and 20 </ b> B intersecting and joining at a predetermined angle θ. The angle θ at which the branch channels intersect is preferably 30 to 180 °.

  Further, as in the example shown in FIG. 15, it is also preferable to provide a narrowed portion of the flow path at the junction 22 or in the vicinity thereof.

  In the fluid mixing device 10, the groove 48 is provided that creates a gap only in the discharge side check valve 16. However, if there is a gap in the suction side check valve 14 and a reverse flow occurs on the suction side, the flow rate is increased. Is even less.

  Further, the configuration for providing the gap is not limited to the groove. For example, by setting the neutral position of the valve body (the position when no external force is applied to the valve body) to a position slightly away from the valve seat, the valve body It takes a long time to sit on the valve seat, and backflow is allowed during this time. In this case, by adjusting the thickness of the valve body, the inner diameter of the hole provided in the center of the valve body, and the distance (gap) from the valve seat at the neutral position of the valve body, The amount can be adjusted. Moreover, a clearance gap can also be formed by roughening the surface roughness of the valve seat.

  The timing chart of FIG. 3 shows an example in which the fluid is alternately discharged from the two diaphragm pumps 13A and 13B, and the fluid is sent toward the discharge port 26 while mixing. However, the period for mixing the fluid and the period for feeding can be provided separately. For example, when only one diaphragm pump is operated, the reverse flow rate is set to 100%, the pumps are operated alternately to mix the fluid, and then the two pumps are operated simultaneously to mix. It is also possible to send out the fluid and repeat this process. Further, even when the reverse flow rate is less than 100%, a period in which the pumps are alternately operated to mainly mix the fluid and a period in which the pumps are simultaneously operated to send the fluid to the discharge port are provided. Also good.

  FIG. 5 is a diagram illustrating another configuration example of the diaphragm pump. The diaphragm pumps 12 </ b> A and 12 </ b> B of the fluid mixing apparatus 10 of FIG. 1 can be replaced with this diaphragm pump 60.

  The diaphragm pump 60 can actively open and close the suction side and discharge side check valves. Hereinafter, the structure will be described. A concave portion 64 is provided in the substrate 62, and the concave portion 64 is covered with a processed plate 66 to form a pump chamber 68 surrounded by these. A portion of the processing plate 66 facing the pump chamber 68 is formed thin and functions as a diaphragm 70. A piezoelectric element 72 is joined to the diaphragm 70 in order to drive it. By applying a voltage to the piezoelectric element 72, the piezoelectric element 72 and the diaphragm 70 are deformed to expand and contract the pump chamber 68.

  A suction side valve 74 and a discharge side valve 76 are provided adjacent to the pump chamber 68. The suction side valve 74 includes a valve seat 78 provided so as to protrude from a portion in which the substrate 62 is carved, and a valve body 80 so as to cover the valve seat 78. The valve body 80 is formed by thinning a part of the processed plate 66, and a piezoelectric element 82 for driving the valve body 80 is joined thereto. The valve seat 78 is provided with a suction side flow path 84, and the valve body 80 can open and close the opening of the flow path. The discharge side valve 76 has the same configuration, and protrudes from the substrate, and has a valve seat 88 having a discharge side flow path 86 therein, and a valve body 90 that faces the valve seat and opens and closes the mouth of the discharge side flow path 86. The piezoelectric element 92 for driving the valve body 90 is provided.

  The suction side valve 74 and the discharge side valve 76 can control the opening and closing of the valves by applying a voltage to the piezoelectric elements 82 and 92. The control timing can be controlled according to the chart shown in FIG. In this case, the voltage applied to the discharge-side piezoelectric element 92 is adjusted to control the lift amount of the valve body 90 and to control the reverse flow rate.

  By using the diaphragm pump 60 provided with the active valve, it becomes possible to change the timing of opening and closing to generate a backflow. FIG. 6 shows an example of a timing chart of opening and closing of the suction side valve 74 and the discharge side valve 76 of the apparatus in which the diaphragm pumps 12A and 12B of the fluid mixing apparatus 10 shown in FIG. 1 are replaced with the diaphragm pumps 60A and 60B. (A) is a figure which shows the flow volume of diaphragm pump 60A, 60B, and is the same as that of FIG. A solid line indicates the pump 60A, and a broken line indicates the pump 60B. (B)-(d) has shown the period when each valve of two pumps is open. From the top of each chart, the opening periods of the suction side valve 74A and the discharge side valve 76A of the diaphragm pump 60A, the suction side valve 74B and the discharge side valve 76B of the diaphragm pump 60B are shown. Moreover, (b) is a case where the backflow does not occur so that the opening periods of the suction side valve and the discharge side valve of the same pump do not overlap. (C) is an example of a case where the suction side valve and the discharge side valve are open during the process of opening and closing the valve, and the back flow rate at this time is relatively small. (D) is a configuration in which the reverse flow rate is increased by actively overlapping the opening periods of the suction side valve and the discharge side valve. The reverse flow rate can be controlled by increasing or decreasing the overlap period. It is also possible to control the reverse flow rate by controlling both the lift amount of the valve body and the opening period. In the case of this chart, the final discharge flow rate is pulsation free.

  The diaphragm pumps 12 and 60 of the fluid mixing apparatus 10 described above can control the deformation amount of the piezoelectric element and the flow rate by controlling the current waveform applied to the piezoelectric elements 36 and 72. In particular, since the amount per discharge can be changed, the discharge amounts of the two pumps can be made different, whereby the mixing ratio of the two types of fluids can be changed.

  Further, when an actively controllable valve such as the diaphragm pump 60 is provided, mixing is performed by repeating the suction / discharge cycle with the suction side valve closed and the discharge side valve opened. Can be promoted more. When the suction side is closed and the discharge side is opened and the two diaphragm pumps 60A and 60B are operated with their phases reversed, fluid reciprocates in the branch flow paths 20A and 20B, thereby promoting mixing. During mixing, the normal control, that is, the valve on the suction side is opened while the volume of the pump chamber is expanding, the valve on the discharge side is closed, and the discharge side is opened while the volume is reduced, Further, the fluid can be sent toward the discharge port by closing the suction side. Further, by actively controlling the opening / closing period of the valve, it is possible to adjust the reverse flow rate, that is, the ratio of the fluid directed to the other pump with respect to the fluid delivered from one pump. When mixing a plurality of fluids that cause a chemical reaction, the fluid mixing device may need to control the reaction rate. Even in such a case, the degree of mixing can be controlled by adjusting the reverse flow rate. In order to slow down the reaction rate, for example, there is a method of setting the phase difference between two pumps to zero. In this way, the laminar flow can be sent without mixing the liquid interface downstream.

  FIG. 7 shows a schematic configuration of a fluid mixing apparatus 100 according to another embodiment of the present invention. The same components as those of the fluid mixing apparatus 10 shown in FIG. The branch channels 20A and 20B of the fluid mixing apparatus 100 are provided with flow meters 102A and 102B and sub chambers 104A and 104B downstream thereof. The sub chambers 104A and 104B are configured such that their volumes change. The discharge side check valves 106A and 106B are general check valves that do not have a structure for allowing a backflow unlike the above-described check valves 16A and 16B.

The sub chamber 104 is formed by constituting a part of the branch channel 20 with a member having elasticity. If a sufficient amount of volume change can be secured, the cross-sectional shape of the flow path can be the same as that of the portion other than the sub chamber 104. However, as will be described later, since the volume change is related to the reverse flow rate, it is preferable to secure a relatively large space in order to increase the volume change. For example, a shallow cylindrical hole can be formed so that the axis of the cylinder is orthogonal to the axis of the branch channel. By covering the cylindrical end surface with an elastic member, the internal volume of the sub chamber 104 changes. Examples of the material of the elastic member include natural or synthetic rubber and silicone resin. By adopting a diaphragm shape as the structure, single crystal silicon, stainless steel (SUS304, SUS316, etc.), titanium, copper and alloys thereof, other metals and alloys thereof, jewelry such as sapphire and diamond, silicon dioxide (SiO) ₂ ), ceramics such as titanium oxide (TiO), zinc oxide (ZnO), manganese oxide (MnO), and hard materials such as polycarbonate and polypropylene can be used as the material of the elastic member. When a diaphragm is employed, a backup member such as a compressible fluid, a gel-like body, or a spring can be disposed on the back surface, that is, on the side opposite to the sub chamber 104 in order to ensure the strength of the diaphragm.

  The elastic member is deformed by the discharge pressure of the pump. When the diaphragm pump 12A is in the discharge stroke, the volume of the sub chamber 104A on this side is increased by the discharge pressure, but the volume of the sub chamber 104B related to the other pump 12B is also increased. The amount of increase in the volume of the sub chamber 104B is the reverse flow rate. At this time, the discharge-side check valve 106B of the diaphragm pump 12B does not allow backflow, so that backflow does not reach upstream from the sub chamber 104B. For this reason, by providing the sub chamber 104, the discharge amount of the diaphragm pump 12 is determined by the displacement of the diaphragm during the discharge period, and it is not necessary to consider the reverse flow rate, so that the discharged flow rate can be reliably grasped. For the same reason, the volumetric efficiency (about 98%) of a general high-precision metering pump can be achieved without reducing the volumetric efficiency of the diaphragm pump.

  It is also possible to measure the flow rate actually discharged by the pump with a flow meter and feed it back to the operation control of the pump. In other words, the voltage waveform applied to the piezoelectric element can be adjusted based on the actual discharge flow rate, and the pump discharge amount can be controlled to be a predetermined value. In this case, the accuracy of the flow rate control is determined by the time delay of the control system and the accuracy of the flow meter, and in fact, when using a metering pump having a high volumetric efficiency rather than performing feedback control, In many cases, the flow rate, mixing ratio, etc. can be controlled with high accuracy.

  FIG. 8 shows a chart of the operation in the case of passively changing in response to the fluid pressure. The flow rate of the diaphragm pump 12A is indicated by a substantially trapezoidal waveform indicated by a solid line, and the flow rate of the pump 12B is indicated by a substantially trapezoidal waveform indicated by a broken line. A value obtained by subtracting the incoming flow rate from the flow rate passing through the sub-chamber 104A, that is, the flow rate exiting from the sub-chamber 104A, is a mountain-shaped waveform indicated by a solid line, and the flow rate passing through the sub-chamber 104B is a broken line. It is shown by the mountain-shaped waveform of the curve shown by. In any waveform, the discharge side flow rate is above the neutral point indicated by the horizontal axis, and the suction side flow rate is below. Also in this case, the final discharge flow rate is pulsation free.

  In order to actively control the volume of the sub chamber 104, a piezoelectric element can be joined to the elastic member of the sub chamber described above, thereby driving the elastic member. 9 and 10 show the configuration of such a subchamber. A part of the branch channel 20 is formed with a substantially cylindrical hole or depression 108. A piezoelectric element 112 is bonded to the elastic member 110, and by applying a voltage to the piezoelectric element 112, the elastic member is deformed like a diaphragm to increase or decrease the volume of the sub chamber 104. Further, by providing or leaving an oxide film on the surface of the silicon substrate in this region instead of providing the depression 108, it is possible to prevent the portion from being bonded to a layer covering this portion from above. Further, in addition to the oxide film on the silicon substrate, it is possible to prevent the bonding with the upper layer by depositing a metal thin film on the surface of the glass substrate, sputtering, or pressing the metal film. In this case, since there is no depression, useless volume can be eliminated.

  FIG. 11 shows a time chart of control in this case. The operations of the diaphragm pumps 12A and 12B are the same as those in the chart of FIG. The control of the sub chambers 104A and 104B is performed when the pump on the opposite side of the pump to which the sub chamber is associated is in the discharge period and operates in the direction of suction, that is, to increase the volume, and the discharge of the pump to which the sub chamber is associated. In the period, it operates in the discharge direction. That is, as shown by the solid line, the control of the sub chamber 104A is a suction period indicated by a single oblique line when the pump 12B on the opposite side is in the discharge period, and two times in the discharge period of the pump 12A on its own side. The discharge period is indicated by heavy diagonal lines. The operation of the sub chamber 104B is a suction period during the discharge period of the pump 12A on the opposite side, and a discharge period during the discharge period of the pump 12B.

  The depression 108 is formed shallowly so that the volume change of the sub chamber does not affect the discharge pressure of the diaphragm pump. That is, the movement of the elastic member 110 is restricted so as not to drop after the elastic member 110 comes into contact with the bottom of the recess 108. There is no displacement limit above.

  Furthermore, a shape memory alloy can be bonded to the elastic member 110 instead of the piezoelectric element 112 shown in FIGS. The shape memory alloy tries to return to its original shape when heated by heating. Also, when heated, the Young's modulus changes and cures, and when cooled and returned to its original temperature, it returns to its original hardness. Utilizing this property, a change in volume is allowed in the discharge period of the pump on the opposite side to allow reverse flow, and a change in volume is suppressed in the discharge period of the pump on its own side so that the pump efficiency does not decrease. To.

  FIG. 12 shows a chart of operations when a shape memory alloy is used. In the discharge period of the related pump in the sub chamber, the shape memory alloy is energized and heated and cured, and in the suction period, the heating is stopped to lower the temperature, and the reverse flow of the fluid discharged from the pump on the opposite side is reduced. Try to allow. In the chart of FIG. 12, the period indicated by double diagonal lines is the period during which the shape memory alloy is cured, and the period indicated by single diagonal lines is the period during which the normal hardness is restored.

  When a shape memory alloy is used, it is also a part of the elastic member, that is, a structure, so that the elastic member can be made thin. Moreover, not only a shape memory alloy but a member which changes in rigidity by some external stimulus can be used.

  FIG. 13 shows a configuration in which gear pumps 120A and 120B, which are rotary displacement pumps, are used instead of a reciprocating pump such as a diaphragm pump. The configuration other than the pump is the same as the configuration of the fluid mixing apparatus 10 shown in FIG. 1, and illustration and description thereof are omitted. The gear pump can reverse the flow by rotating in the opposite direction. Therefore, during the period when one pump (for example, pump 120A) is discharging, the other pump (120B) is reversed, and a part of the fluid discharged by pump 120A is connected to pump 120B. A reverse flow can be generated by pulling it into 20B. The rotary displacement pump such as the gear pump shown in the figure can adjust the discharge amount by the number of rotations thereof, and can ensure quantitativeness.

  As mentioned above, although the pump which makes a discharge flow non-pulsating was described, even when it has a pulsation, it is possible to produce a back flow and to promote mixing.

  Moreover, although the apparatus provided with two pumps and mixed two types of fluid was described, it can also be set as the apparatus which mixes more types of fluids with more pumps. In this case, the branch passages connected to each pump can be merged at one place, and the two branch passages are merged to form a tree-like channel so that the merged channels are further merged. You can also In the case of providing three pumps, the discharge timing can be one by one, or two can be discharged simultaneously.

  As mentioned above, although the apparatus which delivers a fluid with a positive displacement pump was demonstrated, it replaced with a positive displacement pump and the other apparatus which delivers a fluid can be used. For example, a syringe pump can be used, which can be driven intermittently to sequentially send out fluid, and the cylinder can be pulled back to create a backflow. It is also possible to store a fluid in a container or bag having an elastic member such as a rubber bag, contract the volume of the container or the like by the elastic force of the elastic member, and send out the fluid with this contracting force. In this case, an active valve is provided so that the fluid is intermittently sent out by opening / closing control of the valve, and a reverse flow is caused by providing the same configuration as the above-described sub chamber. Furthermore, a drip chamber can be used to send out fluid by a hydrostatic head. As in the case of a container having elasticity, an active valve and a sub chamber are provided to perform intermittent feeding and cause a back flow. In addition, different types of fluid delivery devices can be combined in one device.

  Furthermore, instead of the positive displacement pump, an electromagnetic pump may be used in which a fluid is a magnetosensitive fluid, electricity is applied to the fluid, and a magnetic field is applied to generate a driving force and send out the handling fluid.

  The fluid mixing device described above can be applied to a micro device that handles a minute flow rate. In particular, since the structure is simple and the size can be reduced, it is suitable when it is desired to reduce the amount of fluid to be handled. For example, when blood and GOD (glucose oxidase) are mixed as in blood glucose level measurement, the amount of blood collected and the amount of GOD are better. The blood volume is required to be reduced in order to reduce the burden on the subject. Since GOD is expensive, it is also required to reduce the amount used. In such a case, it is desired that the amount of the sample and reagent to be handled is about microliters or less. However, according to the present apparatus, fluid can be quickly supplied even in an apparatus that handles such a small flow rate. Can be mixed.

  In the case of an apparatus that handles such a small flow rate, the region where the flow tends to be laminar is mainly 0.001 to 1000 μL per discharge of one pump, and even in such a laminar flow region In the apparatus of this embodiment, mixing can be performed satisfactorily.

It is a figure which shows schematic structure of the fluid mixing apparatus 10 of this embodiment. 2 is a cross-sectional view showing an example of a diaphragm pump used in the fluid mixing apparatus 10. FIG. It is a perspective view which shows the shape of the upper surface of the glass substrate 28 of the diaphragm pump of FIG. It is a timing chart which shows an example of operation | movement of the diaphragm pump shown in FIG. It is a figure which shows the mode of the flow of the vicinity of the confluence | merging part of a flow path. 6 is a cross-sectional view showing another example of a diaphragm pump used in the fluid mixing apparatus 10. FIG. It is a chart which shows an example of the operation timing of the diaphragm pump shown in FIG. It is a figure which shows schematic structure of the fluid mixing apparatus 100 of other embodiment. It is a chart which shows an example of the operation timing of the fluid mixing apparatus 100 of FIG. 4 is a cross-sectional view showing a configuration example of a sub chamber 104 of the fluid mixing device 100. FIG. 3 is a perspective view showing a configuration example of a sub chamber 104 of the fluid mixing device 100. FIG. It is a chart which shows another example of the operation timing of the fluid mixing apparatus 100 of FIG. It is a chart which shows another example of the operation timing of the fluid mixing apparatus of FIG. It is a figure which shows the structure using a gear pump. It is a figure which shows an example of the conventional fluid mixing apparatus. It is a figure which shows the example of the shape of the part where a branch flow path merges.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Fluid mixing apparatus, 12 (12A, 12B) Diaphragm pump, 13 (13A, 13B) Pump chamber, 14 (14A, 14B) Suction side check valve, 16 (16A, 16B) Discharge side check valve, 20 (20A , 20B) Branch flow path, 22 confluence, 24 flow paths, 28 substrate, 32 processed plate, 34 diaphragm, 36 piezoelectric element, 40, 44 valve seat, 42, 46 valve body, 48 groove, 60 (60A, 60B) diaphragm Pump, 62 Substrate, 66 Processing plate, 68 Pump chamber, 70 Diaphragm, 72 Piezoelectric element, 74 Suction side valve, 76 Discharge side valve, 78, 88 Valve seat, 80, 90 Valve element, 82, 92 Piezoelectric element, 100 Fluid Mixing device, 102 flow meter, 104 sub chamber, 106 discharge side check valve.

Claims (9)

A fluid mixing device for mixing a plurality of types of fluids,
Provided for each type of fluid, sequentially, a plurality of reciprocating pump having intermittently out feeding of fluid, suction side, the check valve to the flow paths on the discharge side,
A branch flow path connected to each discharge port of each pump;
A main flow path joined by the branch flow paths;
Have
During a discharge stroke of a certain pump, a part or all of the fluid discharged therefrom is caused to flow back into the branch flow path connected to at least one other pump,
A check valve on the discharge side of a certain pump has a part of the fluid discharged into the branch flow channel in the other pump discharge period in which at least one pump other than the pump provided with the check valve discharges the fluid. Allow backflow,
Fluid mixing device. The fluid mixing device according to claim 1,
The discharge-side check valve has a slight gap even when closed, and the backflow is allowed by this gap.
Fluid mixing device. The fluid mixing device according to claim 1,
The discharge-side check valve is a passive valve that opens and closes by the flow of fluid, and has a valve body and a valve seat. When the valve body is seated on the valve seat, a slight gap is formed between them. And the backflow is allowed by this gap,
Fluid mixing device. The fluid mixing device according to claim 1,
The discharge-side check valve is an active valve having a drive unit for opening and closing, and the check valve is opened during at least a part of the discharge period of the other pump, thereby allowing the backflow. The
Fluid mixing device. A fluid mixing device for mixing a plurality of types of fluids,
A plurality of pumps that are provided for each type of fluid, and sequentially and intermittently deliver fluid;
A branch flow path connected to each discharge port of each pump;
A main flow path joined by the branch flow paths;
Have
During a discharge stroke of a certain pump, a part or all of the fluid discharged therefrom is caused to flow back into the branch flow path connected to at least one other pump ,
A sub chamber whose volume changes is provided in the branch flow path.
Fluid mixing device. 6. The fluid mixing apparatus according to claim 5, wherein at least a part of the sub chamber is formed of an elastic body, and the elastic body is deformed by a pressure of an internal fluid to allow back flow. 6. The fluid mixing apparatus according to claim 5, wherein at least a part of the sub chamber is formed of an elastic body, and further includes a drive unit that deforms the elastic body, and the elastic body is deformed to deform the volume of the sub chamber. A fluid mixing device which expands the above to allow the backflow. A fluid mixing device for mixing a plurality of types of fluids,
A plurality of positive displacement rotary pumps that are provided for each type of fluid and that are capable of reverse operation that sequentially and intermittently sends fluid;
A branch flow path connected to each discharge port of each pump;
A main flow path joined by the branch flow paths;
Have
During a discharge stroke of a certain pump, a part or all of the fluid discharged therefrom is caused to flow back into the branch flow path connected to at least one other pump,
During a discharge stroke of a certain pump, at least one other pump is operated in reverse to draw a part of fluid discharged from the certain pump into a branch flow path of the other pump.
Fluid mixing device. A fluid mixing device for mixing a plurality of types of fluids,
A plurality of pumps that are provided for each type of fluid, and sequentially and intermittently deliver fluid;
A branch flow path connected to each discharge port of each pump;
A main flow path joined by the branch flow paths;
Have
During a discharge stroke of a certain pump, a part or all of the fluid discharged therefrom is caused to flow back into the branch flow path connected to at least one other pump ,
The operations of the plurality of pumps include a period controlled to reciprocate a fluid in the branch flow path and a period controlled to send the fluid to the main flow path.
Fluid mixing device.

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