JP2005144215A - Liquid mixing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To satisfactorily mix two or more kinds of liquids supplied at a very small flow rate. <P>SOLUTION: When two kinds of liquids A, B are mixed, the liquid A is sent out by a first pump P<SB>A</SB>to a joining point 16 and the liquid B is sent out by a second pump P<SB>B</SB>thereto. The discharge period of each pump is shifted to each other and the liquids A, B are alternatively discharged. After joining, the liquids A, B flow in a direction of a stream while forming layers. The flow rate near the center of a flow path differs from the flow rate near a wall, a contact area between adjacent layers becomes large, mixing proceeds even when the stream is in a laminar flow state and two liquid mixing is efficiently performed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

  When mixing a plurality of types of liquids while feeding them in a single flow path, an apparatus may be used in which a number of wings, for example, flat plates twisted in the flow path, are fixedly arranged. The flowing liquid swirls and agitates the blade, and as a result, a plurality of types of liquids are mixed. An apparatus for rotating and mixing a blade disposed in a flow path is also known. As shown in FIG. 12, there is also known an apparatus in which flow paths are entangled so that the boundary surfaces of a plurality of types of liquids to be mixed (two types in the figure) become large. The flow paths 100 and 102 through which the two types of liquid flow are separated by a wall 104 formed with irregularities, and these walls reach a predetermined position along the flow. After the wall breaks, the boundary between the two types of liquid becomes a shape similar to the unevenness of the wall, and then mixing proceeds along the flow.

  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 an apparatus for stirring by rotating a blade or the like, a flow path for flowing a minute flow rate fluid is narrow, and it is difficult to arrange a rotating structure in the flow path. Further, when the shape of the boundary wall between the two types of liquids is devised to increase the contact area between the two liquids, the overall volume tends to increase, and the liquid remaining in the apparatus increases. There was a problem that the amount of use of wasted.

  The present invention provides a liquid mixing device that is advantageously mixed even at a minute flow rate such that the flow is laminar.

  The liquid mixing apparatus of the present invention has a pump that intermittently discharges these liquids toward a single flow path for each of a plurality of types of liquids to be mixed, and the discharge period of these pumps is They are offset from each other. Therefore, the fluid that has reached the single flow path is laminated so as to form a layer in the flow direction, but as the flow proceeds, the front and back layers are mixed by diffusion and the mixing proceeds.

  It is preferable that the discharge periods of pumps that discharge different types of liquids do not overlap each other. When the discharge periods overlap, that is, when pumps that handle different types of liquids discharge simultaneously, a layer is formed in the left-right direction of the flow at the position where these different types of fluids merge, and this layer is maintained in the case of laminar flow. Mixing does not progress. Therefore, as described above, the mixing is advanced such that the discharge periods do not overlap so that there is no section in which layers are formed in the left-right direction.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a schematic configuration of a liquid mixing apparatus 10 that mixes two types of liquids A and B according to the present embodiment. The first branch flow path 12 through which the liquid A flows and the second branch flow path 14 through which the liquid B flows merge at the junction 16, and a flow path serving as the main flow path 18 through which both the liquids A and B flow is formed downstream. ing. The lower end of the first branch channel 12 in the figure is connected to a tank (not shown) that stores liquid A, and the second branch channel 14 is also connected to a tank tank (not shown) that stores liquid B in the same manner. Yes. Further, the first and second branch channels 12 and 14, the first pump P _A and second pump P _B respectively provided from tank connected to each of the branch flow paths 12 and 14, the corresponding liquid It sends out toward the junction 16.

FIG. 2 is a cross-sectional view showing a schematic structure of the first and second pumps P _A and P _B. These pumps P _A and P _B have the same structure. The first pump P _A, dig into the substrate 20 in the thickness direction, over the opening of the dug-down part by a diaphragm 22, to form a pump chamber 24, are fabricated. Furthermore, two holes 26 and 28 are formed in the substrate 20 corresponding to the bottom of the pump chamber 24 so as to penetrate the front and back of the substrate. One of these holes is a suction port 26 into which the liquid to be handled is sucked, and the other is a discharge port 28 through which the liquid is discharged. The suction port 26 and the discharge port 28 are provided with check valves 30 and 32, respectively, so that the liquid flows in a certain direction. A piezoelectric element 34 is affixed to the diaphragm 22. The piezoelectric element 34 is deformed when power is supplied from a power source (not shown), and the diaphragm 22 is also deformed accordingly, and the volume of the pump chamber 24 is increased or decreased. Due to the volume change of the pump chamber 24, the liquid is sucked into the pump chamber 24 from the suction port 26 and discharged from the pump chamber 24 through the discharge port 28.

The fluid sent out by the first and second pumps P _A and P _B is directed to the junction 16 and flows downstream from the junction 16 through one main flow path 18.

3 and 4 are diagrams showing the timing of the discharge / suction operation of the first and second pumps P _A and P _B and the fluid flow at that time.

Chart shown on in FIG. 3 (a) discharge of the first pump P _A, a timing of the suction operation. The top of the horizontal axis is the discharge side, and the bottom is the suction side. Are those chart shown below is in the second pump P _B, similarly to the first pump P _A, above the discharge side, the lower is the suction side. FIG. 3A shows that the discharge timings of the two pumps P _A and P _B coincide with each other, and FIG. 3B shows the flow at that time. When the discharge timings coincide with each other, the liquids are simultaneously fed from the two pumps at the confluence point 16, and the liquid A and the liquid B are separated to the left and right with respect to the flow direction as shown in the figure to form a layer. When the flow rate is small and the flow state is a laminar flow, the liquids A and B are hardly mixed with each other in the downstream direction with this layer formed. In order to mix two kinds of liquids, in the liquid mixing apparatus 10 of the present embodiment, the discharge periods of the first pump P _A and the second pump P _B are shifted as shown in FIG. 4, for example.

As shown in FIG. 4A, the discharge periods of the first pump P _A and the second pump P _B are shifted, and the discharge timing when the two pumps are combined is shown in the lowermost chart. FIG. 4B shows the flow when the discharge period is shifted. Liquid A and liquid B flow in layers in the direction of flow. When the flow is laminar, the flow near the center of the flow path is fast, the flow near the wall is slow, the boundary between the liquids A and B is curved in an arcuate shape, and the contact surface between the two liquids increases and mixes. Is promoted. As a result, mixing of the two liquids proceeds downstream.

FIG. 5 is a diagram showing an example of a mixing apparatus that handles more types of liquids. In particular, a liquid mixing apparatus 40 that handles four types of liquids A, B, C, and D is shown. Figure 5 (a), the pump P _A for each type of liquid, P _B, P _C, and P _D are provided, each of these pumps, have the same configuration as the pump shown in FIG. 2 doing. Passage merges flow path from each of the pump P _A and the pump P _B is at the merging point 42, a flow path from each of the pump P _C and the pump P _D are joined at the merging point 44. Further, the flow paths from the pumps P _A and P _B and the flow paths from the pumps P _C and P _D join at the junction 46. Four pumps, so as not to overlap the discharge period of each other, the pump P _A, the pump P _B, the pump P _C, is discharged in the order of the pump P _D is performed. After the junction 42, as shown in FIG. 5B, the liquid A and the liquid B form a layer in the flow direction. As described above, the two liquids are actually mixed in the downstream direction, but here, the layers of the liquids are simply shown clearly. Similarly, after the confluence point 44 of the liquid C and the liquid D, two kinds of liquids are layered in the flow direction as shown in FIG. At the junction 46 where the four types of liquids merge, the position upstream of the layer of liquid B (position X1 shown) is located at this junction 46 and the position downstream of the layer of liquid C (shown). When the pumps P _C and P _D are driven when the position Y is located at the confluence 46, the liquid layers are arranged in the order of driving the four pumps as shown in FIG. 5D.

By adjusting the distance from the merging point 42 to the merging point 46 and the distance from the merging point 44 to the merging point 46, another kind of liquid is inserted into one layer of the one kind of liquid once formed. be able to. For example, when the pumps P _C and P _D are driven when a position in the middle of the layer of the liquid B (position X2 in the drawing) is located at the confluence 46, as shown in FIG. Can interrupt the layers of liquids C and D. In this case, the area of the liquid B that contacts other types of liquids A, C, and D increases, and the mixing of the liquids is further promoted. In this way, adjustment is performed not only on the liquid A and B sides but also on the liquid C and D sides, so that the liquid A or liquid B layer is also inserted into the liquid C and liquid D layers. It is possible. Further, the pump drive order is set as P _A , P _C , P _B , P _D, etc., and the pair of P _A , P _{B and} the group of P _C , P _D are driven alternately to each other. One set of layers can be interrupted by one set of layers, which further facilitates mixing.

  As mentioned above, although the apparatus which mixes two types and four types of liquid was described, the apparatus which mixes three types and five or more types of liquid can be comprised similarly.

  In the liquid mixing apparatuses 10 and 40 described above, the pump that drives the diaphragm using the deformation of the piezoelectric element is used. However, a pump that drives the diaphragm using a solenoid coil can be used instead of the piezoelectric element. . If the armature is protruded by energizing the coil, and the armature is pulled in when the energization is stopped, the energization enables pulse driving as in the diaphragm pump described above. Furthermore, a mechanical drive, a fluid drive pump, etc. can be utilized. The pumps used in the liquid mixing apparatuses 10 and 40 are pulse-driven pumps having a very short discharge period, and the discharge periods of the pumps can be easily shifted so that they do not overlap. In the case of a pump driven by a cam, a crank, or the like, the discharge period of each pump is relatively long, and the overlap of the discharge periods of the pumps tends to be long. In order to shift the discharge period of each pump, a lost motion pump can be used.

  FIG. 7 is a diagram illustrating an example of a lost motion mechanism in the fluid pressure pump. The plunger 70 is driven by a crank mechanism 72 and reciprocates in the left-right direction in the drawing. The reciprocating motion of the plunger 70 causes a change in volume of the fluid pressure chamber 74, whereby the flexible tube 76 repeatedly contracts and expands. The operation of the tube 76 causes the volume of the handling fluid chamber 78 to fluctuate, and the handling fluid is sent out. The above operation is common to general fluid pressure pumps.

  The main part of the lost motion mechanism of this example is the structure of the plunger 70 and the sleeve 80. The plunger 70 has a mortar-shaped hole 82 formed at the tip (right side in the figure), and the space in the hole 82 is integrated with the fluid pressure chamber 74. Further, a through hole 84 that communicates with the outer surface of the plunger 70 is provided in the vicinity of the bottom of the mortar-shaped hole 82. The inner peripheral surface of the sleeve 80 has a shape in which a part of a surface in contact with the outer surface of the plunger 70 is formed. That is, the inner peripheral surface of the sleeve 80 that is sandwiched between the broken line orthogonal to the axis of the plunger 70 and the broken line that crosses diagonally is spaced from the outer surface of the plunger 70. Hereinafter, this portion is referred to as a gap portion 86. The gap portion 86 is further connected to the outside by a communication hole 88 communicating with the outer surface of the sleeve.

  As shown in FIG. 8A, when the plunger 70 is on the left side and the through hole 84 is blocked by the inner peripheral surface of the sleeve 80, the movement of the plunger 70 is transferred to the tube 76 via the fluid. Communicated. However, as shown in FIG. 8B, when the plunger 70 moves to the right and the through hole 84 is in contact with the gap portion 86, the fluid pressure chamber 74 has the mortar-shaped hole 82, the through hole 84, and the gap portion 86. It will be in the state which communicated with the exterior via. Therefore, the movement of the plunger 70 is not transmitted to the tube 76. That is, when the through hole 84 is blocked by the inner peripheral surface of the sleeve 80, the movement of the plunger 70 is effectively used, and when the through hole 84 is positioned in the gap portion 86, the movement of the plunger 70 is effective. It is not used and does not cause discharge of the handling fluid.

  Further, the illustrated lost motion mechanism can change the effective stroke amount of the plunger 70. A gear 90 is formed around the plunger 70, and an adjustment shaft 94 having a pinion 92 that meshes with the gear 90 is provided. When the adjustment shaft 94 is rotated, the sleeve 70 is rotated about the axis, and the direction of the gap 86 is changed as shown in FIG. As a result, the intersection of the straight line through which the through hole 84 moves and the boundary line of the gap 86 changes, and the effective stroke amount is changed.

  According to the above-described lost motion mechanism, the handling liquid is discharged at the initial stage of the discharging process in which the plunger 70 moves rightward, and is not discharged when the through hole 84 reaches the gap portion 86. The period during which the handling liquid is discharged, that is, the discharge amount can be changed.

Figure 9 is a diagram showing three pumps P _A having a lost motion mechanism shown in Figure 7, P _B, the P _C, the case where the liquid mixing device, a timing chart according to the discharge amount . The upper side of the shaft is the discharge side and the lower side is the suction side. Each of the pumps P _A , P _B , and P _C discharges at the beginning of the discharge stroke (the hatched portion in the figure). The bottom chart shows the discharge periods of each pump in an overlapping manner, and the discharge periods of two pumps partially overlap. The state of the liquid in the joined pipe part at this time is shown in FIG. In the portion where the discharge periods of each pump overlap, there are portions where layers are formed on the left and right with respect to the direction of flow, but as a whole, layers are formed in the direction of flow. This promotes mixing. In addition, although the boundary of each liquid layer is clearly shown in the figure, in practice, the mixing proceeds downstream and the boundary becomes blurred.

  FIG. 11 is a diagram illustrating an example of a mechanical lost motion mechanism. The basic mechanism is to deform the diaphragm (not shown) by causing the crosshead 54 to reciprocate by an eccentric cam 52 fixed to the drive shaft 50 to cause a volume change in the diaphragm chamber 56 on the left side of the figure. It is. The spring 58 urges the cross head 54 so that the right end of the cross head 54 abuts against the eccentric cam 52. When the cross head 54 moves to the right in the drawing and reaches a predetermined position, it comes into contact with the stopper 60 and then separates from the eccentric cam 52 and stops moving. The eccentric cam 52 continues to rotate, and when the stopped cross head 54 comes into contact with the surface thereof, the cross head 54 is pushed to the left against the urging force of the spring 58. Therefore, of the stroke by the eccentric cam 52, the movement of the eccentric cam becomes invalid during the period in which the cross head 54 comes into contact with the stopper 60 and moves away from the eccentric cam 52, and no discharge is performed. Further, the stopper 60 is provided with a screw 62, and the stroke amount of the cross head 54 can be changed by adjusting the advancement amount of the stopper 60.

It is a figure which shows schematic structure of the liquid mixing apparatus of this embodiment. Pump P _A in FIG. 1 is a diagram showing a structure of a P _B. It is a figure which shows the case where discharge of two pumps is performed simultaneously in the apparatus of FIG. It is a figure which shows the case where discharge of two pumps is shifted in the apparatus of FIG. It is a figure which shows the structure of the apparatus which mixes four types of liquids. It is a figure which shows the mode after the confluence | merging point of the liquid sent out by the apparatus of FIG. It is a figure which shows an example of a hydraulic lost motion mechanism. It is operation | movement explanatory drawing of the mechanism of FIG. It is a chart which shows the discharge timing of each pump of the liquid mixing apparatus comprised with the pump which has a lost motion mechanism. It is a figure which shows the mode of the liquid sent out according to the chart of FIG. It is a figure which shows an example of a mechanical lost motion mechanism. It is a figure which shows an example of the conventional liquid mixing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Liquid mixing apparatus, 12 1st branch flow path, 14 2nd branch flow path, 16 confluence | merging point, 18 flow paths, P _A 1st pump, P _B 2nd pump, A, B liquid.

Claims (3)

A liquid mixing apparatus for mixing a plurality of types of liquids,
It is provided for each type of the liquid, has a pump that intermittently discharges the liquid of the type toward a single flow path, and the discharge periods of the pumps that discharge different types of liquid are shifted,
Liquid mixing device.   The liquid mixing apparatus according to claim 1, wherein the discharge periods of the pumps that discharge the different types of liquids do not overlap each other.   3. The liquid mixing apparatus according to claim 1, wherein the flow of the single flow path is used in a flow velocity region where the flow is a laminar flow. 4.

Images